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Menace of Substance Abuse in Today’s Society: Psychosocial Support to Addicts and Those with Substance Use Disorder

DOI: 10.31038/IJNM.2023421

Abstract

Substance abuse among youths has been a problem to society in General. The continuous use of psychoactive substances among adolescents and youths has become a public concern worldwide because it potentially causes deliberate or unintended harm or injury. The consequences of drug abuse are not only on the individual user but also on his or her offspring, family and the society. This seminar topic discussed some drugs that are commonly abused by adolescents and youths such as cannabis, cocaine, amphetamine, heroin, codeine, cough syrup and tramadol. It also discussed the sources where abusers obtained drugs as well possible effects in terms of physical, psychological and social terms. The risk factors and the reason for substance abuse was discussed, how substance abuse interrupt the brain, which also tells us the ways of cubbing the menace of substance abuse by creating awareness about drug abuse and their adverse consequences through the aid of appropriate mass media tools. This write-up also discussed method of delivering customized information suitable to the target audience such as family, schools, workers, religious organization, homes in a sensitive manner. Also discussed is the strategies to use in collaboration with international agencies to monitor the sale of over-the-counter drugs and enforcing stricter penalties for individuals who are involved in trade of illicit drugs and many more. Recommendation are made where call on all categories of people including government ,family, community and National Agency for Food and Drug Administration and Control (NAFDAC) to contribute to preventing the menace of substance abuse. If the Nigerian youths should stop drug abuse, they will be useful to themselves, their families and the society in general.

Keywords

Substance abuse, Psychoactive substance, Society

Introduction

Substance abuse has been a cause of many debilitating conditions such as schizophrenia and psychosis, leading to psychiatric admissions. Substance abuse is emerging as a global public health issue. The recent world drug report-2019 of the United Nations Office on Drugs and Crime (UNODC) estimated that 271 million (5.5%) of the global population (aged between 15 and 64 years) had used drugs in the previous year. Also, it has been projected that 35 million individuals will be experiencing drug use disorders. Furthermore, the Global Burden of disease Study (2017), estimated that there were 585,000 deaths due to drug use, globally. The burden of drug abuse (usage, abuse, and trafficking) has also been related to the four areas of international concern, viz. organized crime, illicit financial flows, corruption, and terrorism or insurgency. Therefore, global interventions for preventing drug abuse including its impact on health, governance, and security, requires a wide spread understanding of the prevalence, frequently implicated drugs, commonly involved population, sources of the drugs and risk factors associated with the drug abuse. In Nigeria, the burden of drug abuse is on the rise and becoming a public health concern. Nigeria, which is the most populous country in Africa, has developed a reputation as a center for drug trafficking and usage mostly among the youth population, in which the menace is giving birth to a generation of drug addicts. Oftentimes, young men are seen with bottles of carbonated drinks (soft drinks), but laced with all kinds of intoxicating content. They move about with the soft drink bottles and sip slowly for hours while unsuspecting members of the public would easily believe that it is mere harmless soft drink.

According to Ladipo, a consultant psychiatrist at the Lagos University Teaching Hospital (LUTH), said that he had handled lot of mental cases in his career as fallouts of drug abuse, which often lead to mental disorder. He also stated that the effects of drug abuse and wrong use do not only take a toll on the individuals and their families but on society at large. According to UNODC, report on Drug use in Nigeria (the first large-scale, nationwide national drug use survey in Nigeria), one in seven persons (aged 15-64 years) had used a drug in the past year. Also, one in five individuals who had used drug in the past year is suffering from drug related disorders. Drug abuse has been a cause of many criminal offences such as theft, burglary, sex work, and shoplifting. A prevalence of 20-40% and 20.9% of drug abuse was reported among students and youths, respectively. Commonly abused drugs include cannabis, cocaine, amphetamine, heroin, diazepam, codeine, cough syrup and tramadol. Sources where abusers obtained drugs, were pharmacies/patent medicine shops, open drug markets, drug hawkers, fellow drug abusers, friends, and drug pushers. Drug abuse was common among undergraduates and secondary school students, youths, commercial bus drivers, farmers, and sex workers. Reasons stated for use include but not limited to increase physical performance, stress and to derive pleasure. Poor socioeconomic factors and low educational background were the common risk factors associated with drug abuse [1-10].

Objectives of the Seminar

To identify the reasons and perceived benefits for substance abuse
To identify psychological and social effects of substance abuse.
To examine psychosocial supports rendered to substance users and addicts.
To stimulate further discussions and research thoughts in an attempts to finding solutions to the menace

Clarification of Concepts

i. A Drug

It is any substance other than food that influences motor, sensory, cognitive or other bodily processes (APA, 2022).

ii. Drug Misuse

It is the use of a substance for a purpose not consistent with legal or medical guidelines (WHO, 2006).

iii. Psycho-Active Substance

Are substances that, when taken in or administered into the system, affect mental process, e.g., perception, consciousness, cognition or mood and emotions (WHO,2022).

iv. Substance Abuse

This, according to International Classification of Diseases (ICD10), is a pattern of psychoactive substance use that is capable of causing damage to physical or mental health. According to Diagnostic and statistical manual of mental disorders (DSM IV), it is a maladaptive pattern of substance use leading to significant clinical/social/legal/occupational distress or mental ill-health in the last 12 months.

Substance abuse can also be defined as;

Use of drugs without physician’s prescription.
Use of illicit drugs or legally banned drugs.

v. Addiction

This is a compulsive, chronic, physiological or psychological need for a habit forming substance, behaviour or activity having harmful effects and typically causing well defined symptoms such as irritability, anxiety, tremors upon withdrawal (NIH, 2019).

vi. Psychosocial

This are structured psychological or social interventions used to address substance-related problems (APA, 2022).

Literature Review

According to International Classification of Diseases ICD10 (2022), substance abuse as a pattern of psychoactive substance uses that is capable of causing damage due to physical or mental ill health. Substance abuse is emerging as a global public health issue, which is needed to be addressed. The effect of drug is due to the organism taking them and these drugs could be beneficial or harmful physically, psychological or physiologically. When the effects of drugs are beneficial, the drug is said to be serving its purpose but if otherwise, then a problem exists According to Abiodun et al. 1 in 7 persons aged 15-64 years in Nigeria had used a drug (other than tobacco and alcohol) in the past year. The past year prevalence of any drug use is estimated at 14.4% (range 14.0% -14.8%), corresponding to 14.3 million people aged 15-64 years who had used at least one psychoactive substance in the past year for non-medical purposes. Among every 4 drug users in Nigeria, 1 is a woman. More men (annual prevalence of 21.8% or 10.8 million men) than women (annual prevalence of 7.0% or 3.4 million women) reported past-year drug use in Nigeria. The highest levels of any past-year drug use were among those aged 25-39 years. 1 in 5 persons who had used drugs in the past year is suffering from drug user disorders. Cannabis is the most commonly used drug. An estimated 10.8% of the population or 10.6 million people had used cannabis in the past year. The average age of initiation of cannabis use among the general population was 19 years. Geographically, the highest past-year prevalence of drug use was found in the southern geopolitical zones (past year prevalence ranging between 13.8 percent and 22.4 percent) compared to the northern geopolitical zones (past year prevalence ranging between 10 percent and 13.6 percent). Two-thirds of people who used drugs reported having serious problems as result of their drug use, such as missing school or work, doing a poor job at work/school or neglecting their family or children.

Classification of Substance of Abuse

Classification of Substance of Abuse is given in Table 1.

Table 1: Classification according to Diagnostic Systematic Manual IV and International Classification of Diseases 10.

S/N	DSM(IV)	ICD10
1.	Alcohol	Alcohol
2.	Stimulants (cocaine, amphetamines)	Other substances including caffeine
3.	Caffeine	____
4.	Cannabis	Cannabinoids
5.	Hallucinogens (lysergic acid, ecstasy, ketamine)	Hallucinogen
6.	Inhalants (fumes from petrol, glue, adhesive)	Volatile solvents
7.	Tobacco	Tobacco
8.	Opioid (morphine, pentazocine, pethidine, tramadol)	Opioid
9.	CNS depressants (sedatives, hypnotics, anxiolytics)	Sedatives, hypnotics
10.	Unknown substance/others (fecal, cow dump)	Unknown substances/others

Substance Abuse Stages

In discussing substance abuse, it is generally agreed that substance is not a one-stage process. According to Brookdale, there are seven stages of substance abuse, namely:

Stage 1: Initiation
Stage 2: Experimentation
Stage 3: Occasional user
Stage 4: Regular user
Stage 5: Risky user
Stage 6: Dependent
Stage 7: Addiction

1. Initiation Stage

This is the first stage during which time the individual tries a substance for the first time. This can happen at almost any time in a person’s life, but according to National Institute on Drug Abuse, the majority of people with an addiction tried their drug of choice before 18 and had a substance use disorder by 20. The reasons a teenager experiments with drugs can vary widely, but two common reasons are because of either curiosity or peer pressure. This latter choice is made with intent of trying to fit in better with that particular group of peers. Another reason that teenagers are more likely to try a new drug than most age groups is due to how the prefrontal cortex in their brain is not yet completely developed. This affects their decision-making process, and as a result many teenagers make their choice without effectively considering the long-term consequences of their actions.

2. Experimental Stage

At the experimentation stage, the user has moved past simply trying the drug on its own and is now taking the drug in different contexts to see how it impacts their life. Generally, in this stage, the drug is connected to social actions, such as experiencing pleasure or relaxing after a long day. For teenagers, it is used to enhance party atmospheres or manage stress from schoolwork. Adults mainly enter experimentation either for pleasure or to combat stress. In this stage, there are little to no cravings for the drug and the individual will still be making a conscious choice of whether to use or not. They may use it impulsively or in a controlled manner, and the frequency of both options mainly depends on a person’s nature and reason for using the drug. There is no dependency at this point, and the individual can still quit the drug easily if they decide to. Some youths repulsed by first unpleasant experiment never to use it again. Others, however assured by the more seasoned users become occasional users

3. Occasional User Stage

The new user seems to be passive accepting drugs if and when offered rather than seeking it out himself, such person believes he or she can handle the situation.

4. Regular User Stage

As a person continues to experiment with a substance, its use becomes normalized and grows from periodic to regular use. This does not mean that they use it every day, but rather that there is some sort of pattern associated with it. The pattern varies based on the person, but a few instances could be that they are taking it every weekend or during periods of emotional unrest like loneliness, boredom or stress. At this point, social users may begin taking their chosen drug alone, in turn taking the social element out of their decision. The drug’s use can also become problematic at this point and have a negative impact on the person’s life. For example, the individual might begin showing up to work hung-over or high after a night of drinking alcohol or smoking marijuana. There is still no addiction at this point, but the individual is likely to think of their chosen substance more often and may have begun developing a mental reliance on it. When this happens, quitting becomes harder, but still a manageable goal without outside help. At this stage, users actually seek after the drugs and maintain their own supply; they show high motivation to get on drugs

5. Risky User Stage

The individual’s regular use has continued to grow and is now frequently having a negative impact on their life. While a periodic hangover at work or an event is acceptable for Stage 3, at Stage 4 instances like that become a regular occurrence and its effects become noticeable. Many drinkers are arrested for a DUI (Driving Under the influence) at this point, and all users will likely see their work or school performance suffer notably. The frequent use may also lead to financial difficulties where there were none before. Although the user may not personally realize it, people on the outside will almost certainly notice a shift in their behavior at this point. Some of the common changes to watch out for in a drug user include:

Borrowing or stealing money
Neglecting responsibilities such as work or family
Attempting to hide their drug use
Hiding drugs in easily accessible places (like mint tins)
Changing peer groups

6. Dependent Stage

This stage, the person’s drug use is no longer recreational or medical, but rather is due to becoming reliant on the substance of choice. This is sometimes viewed as a broad stage that includes forming a tolerance and dependence, but by now, the individual should already have developed a tolerance. As a result, this stage should only be marked by a dependence, which can be physical, psychological, or both.

For a physical dependence, the individual has abused their chosen drug long enough that their body has adapted to its presence and learned to rely on it. If use abruptly stops, the body will react by entering withdrawal. This is characterized by a negative rebound filled with uncomfortable and sometimes dangerous symptoms, that should be managed by medical professionals. In most cases, individuals choose to continue their use, rather than seeking help, because it is the easiest and quickest way to escape withdrawal.

7. Addictive Stage

At this stage, the drug becomes a major part of the user’s life. The user become obsessed with drugs obtaining them at all cost without consideration for food, job, family etc. Individuals at this stage feel as though they can no longer deal with life without access to their chosen drug, and as a result, lose complete control of their choices and actions. The behavioral shifts that began during Stage 4 will grow to extremes, with the user likely giving up their old hobbies and actively avoiding friends and family. They may compulsively lie about their drug use when questioned and are quickly agitated if their lifestyle is threatened in any way. Users, at this point, can also be so out of touch with their old life that they do not recognize how their behaviors are detrimental and the effects that it has had on their relationships.

8. Crisis/Treatment Stage

The final stage of addiction is the breaking point in a person’s life. Once here, the individual’s addiction has grown far out of their control and now presents a serious danger to their well–being. It is sometimes referred to as the crisis stage, because at this point the addict is at the highest risk of suffering a fatal overdose or another dramatic life event.

Of course, while crisis is the worst-case scenario for this stage, there is also a positive alternative that fits here instead. Either on their own or as a result of a crisis, this is when many individuals first find help from a rehab center to begin receiving treatment. As a result, this stage can mark the end of their addiction, as well as the start of new life without drugs and alcohol, that is filled with hope for the future

Drug/Substance Dependence

According to DSM IV (2018), it is defined as a maladaptive pattern of substance use leading to clinically significant impairment or distress occurring at any time in the same 12 months period as manifested by 3 or more of the following;

1. Tolerance

The individual needs a higher dose of the substance to achieve the usual initial satisfactory effect or the current dose doesn’t give the usual initial satisfactory effect.

2. Primacy

The substance of abuse becomes the priority in the abuser’s hierarchy of needs.

3. Withdrawal

This occurs once an abuser stops ingesting the substance the body begins to react to it negatively e.g. an individual abusing Valium (Diazepam) and stopped suddenly such person can experience seizures, insomnia.

Opioid withdrawal symptoms include; excessive yawning, tearing, diarrhea, diaphoresis, joint pain, vomiting

4. Harmful Use

Regardless of the negative effect the abuser continually engage in, the abuse even with the knowledge of its detrimental effects.

5. Inability to Cut Down

An individual who voluntarily stopped abusing substances finds himself/herself engaging in it.

6. Excessive Craving

The individual finds the substance pleasurable and ensure to find it at all cost.

Risk Factors Associated With Substance Abuse

Age (15-24 yrs)
Male Gender
Siblings or parental exposure
Parental deprivation (divorce, separation, death of spouse)
Exposure to high-risk job (breweries, bar, tobacco companies)
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Poor economic status
Experiment/curiosity: Experimental Curiosity: Curiosity to experiment the unknown facts about drugs thus motivates adolescents into drug use. The first experience in drug abuse produces a state of arousal such as happiness and pleasure which in turn motivate them to continue.
Peer pressure: Peer Group Influence: Peer pressure plays a major role in influencing many adolescents into drug abuse. This is because peer pressure is a fact of teenage and youth life. As they try to depend less on parents, they show more dependency on their friends.
Lack of parental supervision: Many parents have no time to supervise their sons and daughters. Some parents have little or no interaction with family members, while others put pressure on their children to pass exams or perform better in their studies. These phenomena initialize and increases drug abuse.
Personality Problems due to socio-economic Conditions: Adolescents with personality problems arising from social conditions have been found to abuse drugs. The social and economic status of most Nigerians is below average. Poverty is widespread, broken homes and unemployment is on the increase, therefore our youths roam the streets looking for employment or resort to begging. These situations have been aggravated by lack of skills, opportunities for training and re-training and lack of committed action to promote job creation by private and community entrepreneurs. Frustration arising from these problems lead to recourse in drug abuse for temporarily removing the tension and problems arising from it.
The Need for Energy to Work for Long Hours: The increasing economic deterioration that leads to poverty and disempowerment of the people has driven many parents to send their children out in search of a means of earning something for contribution to family income.These children engage in hawking, bus conducting, head loading, scavenging, serving in food canteens etc. and are prone to drug taking so as to gain more energy to work for long hours.
Availability of the Drugs: In many countries, drugs have dropped in prices as supplies have increased.

Theories of Drug Addiction

There are several theories that model addiction which are genetic theories, exposure theories (both biological and conditioning), and adaptation theories.

1. Genetic Theory

According to Danielle, stated that Genetic influences affect substance use and substance use disorders but largely are not specific to substance use outcomes.The genetic theory of addiction, known as addictive inheritance, attempts to separate the genetic and environmental factors of addictive behavior. Numerous large-scale twin studies have documented the importance of genetic influences on how much people use substances (alcohol, tobacco, other drugs) and the likelihood that users will develop problems. However, twin studies also robustly demonstrate that genetic influences affect multiple forms of substance use (alcohol, illicit drugs) as well as externalizing behaviors such as adult antisocial behavior and childhood conduct disorder. Accordling to stated that the majority of genetic influence on substance use outcomes appears to be through a general predisposition that broadly influences a variety of externalizing disorders and is likely related to behavioral undercontrol and impulsivity, which is a heterogeneous construct in itself.

2a. Exposure Theories: Biological Models

The exposure model is based on the assumption that the introduction of a substance into the body on a regular basis will inevitably lead to addiction. These theories suggest that brain chemistry, brain structure, and genetic abnormalities cause human behavior. The biological, as opposed to the conditioning models, believe that this is a consequence of biology. Underlying the exposure model is the assumption that the introduction of a narcotic into the body causes metabolic adjustments requiring continued and increasing dosages of the drug in order to avoid withdrawal. Although changes in cell metabolism have been demonstrated, as of yet they have not been linked with addiction. Some theorize that those drugs that mimic endorphins (naturally occurring pain killers), if used on a regular basis, will reduce the body’s natural endorphin production and bring about a reliance on the external chemical agent for ordinary pain relief. The neurological basis of substance abuse is an example of the biological models, as shown below (Figure 1).

Figure 1: Neuro-Biological Basis of Drug Dependence

Dependence results from complex interaction of psychological effects of substance in brain area associated with motivation and emotion, combined with learning. Some area in the brain are responsible for pleasure which causes release of dopamine, for example dopamine level increases after sexual intercourse and intake of favorite meal, but for drug abusers, drugs became substituted for the activities that increases the level of dopamine, the brain learns to reinforce the pleasure by stimulating more of eating. The brain learns to substitute natural substances with natural activities and it increases dopamine level which causes increase pleasurable effect which is desired.

Anatomical Areas Involved in Drug Dependence

Nucleus accumbiens
Mesolimbic pathway in mid brain
Central tegmental

2b. Exposure Theories: Conditioning Models

The basis of conditioning theories is that addiction is the cumulative result of the reinforcement of drug administration. The substance acts as a powerful reinforcer and gains control over the user’s behavior. In contrast to the biological models of the exposure theories, these conditioning models suggest that anyone can be driven to exhibit addictive behavior given the necessary reinforcements, regardless of their biology. The advantage of this theory is that it offers the potential for considering all excessive activities along with drug abuse within a single framework: those of highly rewarding behavior. There are many reinforcement models that have been defined including the opponent- process model of motivation and the well-known classical conditioning model. Both of these models define addiction as a behavior that is refined because of the pleasure associated with its reinforcement.

3. Adaptation Theories

The adaptation theories include the psychological, environmental and social factors that influence addiction. Advocates of these theories have analyzed how expectations and beliefs about what a drug will do for the user influence the rewards and behaviors associated with its use. They recognize that any number of factors, including internal and external cues, as well as subjective emotional experiences, will contribute to addictive potential. They support the views that addiction involves cognitive and emotional regulation to which past conditioning contributes.

The adaptation theory has also broadened the scope of addiction into psychological realms. Investigators have noted that drug users rely on drugs to adapt to internal needs and external pressures.

Common Signs of Drug Abuse

According to Williams, the common signs include:

A. Physical Warning Signs of Substance Abuse

These include

Bloodshot eyes, pupils larger or smaller than usual.
Changes in appetite or sleep patterns.
Sudden weight loss or gain.
Deterioration of physical appearance, personal grooming habits.
Unusual smells on breath, body, or clothing.
Tremors, slurred speech, or impaired coordination.

B. Behavioral Signs Of Substance Abuse

These include:

Drop in attendance and performance at work or school.
Unexplained need for money or financial problems. May borrow or steal to get it.
Engaging in secretive or suspicious behaviors.
Sudden change in friends, favorite hangouts, and hobbies.
Frequently getting into trouble (fights, accidents, illegal activities).

C. Psychological Warning Signs Of Substance Abuse

These include:

Unexplained change in personality or attitude.
Sudden mood swings, irritability, or angry outbursts.
Periods of unusual hyperactivity, agitation, or giddiness.
Lack of motivation; appears lethargic
Appears fearful, anxious, or paranoid, with no reason.

Reasons for Substance Abuse in Nigeria

The commonly reported reasons include the following:

To increase physical performance
To derive pleasure
Desire to relax/sleep
To keep awake
To relieve stress
To relieve anxiety
Unemployment
Frustration
Easy access

Effects of Substance Abuse

The implications of substance abuse to the life of an individual are enormous and can be categorized as Physical, social and Psychological.

A. Physical Impact

There are also a number of issues affecting the physical health of the individual who is abusing drugs over a sustained period of time. According to the National Institute on Drug Abuse (2019), long-term drug abuse can affect:

The Kidneys. The human kidney can be damaged both directly and indirectly by habitual drug use over a period of many years. Abusing certain substances can cause dehydration, muscle breakdown, and increased body temperature—all of which contribute to kidney damage over time. Examples are, heroin, cocaine, marijuana.
The Liver. Liver failure is a well-known consequence of alcoholism, but it also can occur with individuals using opioids, steroids, inhalants, or habitually over many years. The liver is important for clearing toxins from the bloodstream, and chronic substance abuse can overwork this vital organ, leading to damage from chronic inflammation, scarring, tissue necrosis, and even cancer, in some instances. The liver may be even more at risk when multiple substances are used in combination.
The Heart. Many drugs have the potential to cause cardiovascular issues, which can range from increased heart rate and blood pressure to aberrant cardiac rhythms and myocardial infarction (i.e., heart attack). Injection drug users are also at risk of collapsed veins and bacterial infections in the bloodstream or heart.
The Lungs. The respiratory system can suffer damage related to smoking or inhaling drugs, such as marijuana and crack cocaine. In addition to this kind of direct damage, drugs that slow a person’s breathing, such as heroin or prescription opioids, can cause serious complications for the user.

Physical Signs Include

Insomnia
Tremor
Thought disturbance
Drowsiness
Weakness
Coma
Respiratory depression (depression of the central nervous system)
Sexually transmitted diseases(e.g. HIV/AIDS, hepatitis)
Death

B. Social Impact

Addiction creates social issues and public health concerns that extend beyond the home, school, and workplace to negatively impact larger groups of individuals.

Substance Abuse and the Home: Unfortunately, families all throughout society know the impact of addiction. If a person’s spouse or parent is abusing drugs, the results can be life-altering. It can result in financial hardships (due to job loss or money being diverted to fuel the habit). It may also cause reckless behavior that puts the family at risk. Addiction affects the entire family unit when one member is suffering.

Many cases of domestic violence within relationships are related to substance abuse. Addiction can happen on both sides of the conflict, not only by the abuser but also by the victim who uses drugs to cope. Drug use in the family is not limited to spouses or parents. Adolescents, especially during times of transition, may find themselves struggling with substance use. Children may experience maltreatment (including physical and sexual abuse and neglect), which may require the involvement of child welfare. Watching their parents suffer from substance use disorders may result in long-term mental and emotional disorders and delayed development. Children whose parents abuse drugs are more likely to end up using drugs or alcohol, as well.

Substance Abuse and the Workplace: Drug abuse social issues occur in the workplace, the substance use of employees can cause problems. An individual’s drug use will likely impact their work performance. Or, it may even stop them from going to work entirely. Substance abuse can lead to:
Decreased work productivity
Increased lateness and absences
Inappropriate behaviors at work, such as selling drugs to co-workers

These could lead to disciplinary actions and dismissal. Further, drug and alcohol abuse can lead to impaired judgment, alertness, and motor coordination, creating unsafe workplace conditions especially in an environment with heavy machinery.

Social Vices

One of the social effects of drug abuse on society is its direct link on criminal acts, murders etc. that affects the society at large.

D. Psychological Impacts

Substance abuse and mental health are linked because the psychological effects of drug addiction, including alcohol, cause changes in body and brain. A careful balance of chemicals keeps the cogs turning inside the body, and even the smallest change can cause one to experience negative symptoms.

Anxiety . There are a lot of similarities between anxiety and the effects of stimulants such as cocaine and methamphetamine. Conversely, using central nervous system depressants can also increase the risk of a person developing anxiety. A person could have a long-standing pattern of drug abuse and consequently develop anxiety problems. Many substances, particularly stimulants like cocaine, can cause anxiety as a dose-dependent side effects. Other drugs, like benzodiazepines, can bring about increased anxiety as part of their withdrawal syndromes.

Anxiety is best described as a disorder of the fight-or-flight response, where someone perceives danger that isn’t there. It includes the following physical and mental symptoms:

Rapid heart rate
Excessive worrying
Sweating
An impending sense of doom
Mood swings
Restlessness and agitation
Tension
Insomnia

Additionally, many addicts experience anxiety around trying to hide their habits from other people. In a lot of cases, it’s difficult to tell whether anxious people are more likely to abuse substances or if drugs and alcohol cause anxiety.

Depression. There is a clear association between substance abuse and depression. This relationship could be attributed to preexisting depression that led to drug abuse or it could be that substance use caused changes in the brain that increased depressive symptoms. Some people use drugs to self-medicate symptoms of depression, but this only alleviates the symptoms while the user is high. It may even make depression symptoms worse when the user is working through withdrawal. Many drugs have a withdrawal syndrome that includes depression or other mood disturbances, which can complicate recovery. The main symptoms associated with depression are:
Hopelessness
Lack of motivation
Dysregulated emotion
Loss of interest
Sleep disturbances
Irritability
Weight gain or loss
Suicidal ideation
Paranoia. Some drugs, like cocaine and marijuana, can cause feelings of paranoia that may amplify with long-term abuse. On top of this, people struggling with addiction may feel that they need to hide or lie about their substance use, indicating a fear of being caught. The fact that many substances of abuse are illegal can also contribute to mounting feelings of paranoia among long-term substance users.
Shame and Guilt. There is a stigma attached to addiction in society, and there’s a lot of guilt and shame for the individuals who struggle with the condition. Often, this is adding fuel to a fire that was already burning strong. People with substance use disorders tend to evaluate themselves negatively on a regular basis, which is a habit that has its roots in childhood experiences. Continual negative self-talk adds to feelings of shame and guilt. When you constantly feel as if you’ve done something wrong, it’s tempting to try to cover up these challenging emotions with drugs and alcohol. These unhelpful emotions contribute to the negative feedback loop that sends people spiraling into addiction.
A Negative Feedback Loop. From an outside perspective, someone with an addiction looks like they’re repeatedly making bad choices and ignoring reason. However, the truth is far more complicated and nuanced so much so that it can be very difficult for people to overcome a substance use disorder without inpatient or outpatient treatment. This is partly due to a negative feedback loop that occurs in the mind. When someone is addicted to drugs or alcohol, they feel a sense of comfort they haven’t been able to get elsewhere. Inevitably, this feeling is replaced by guilt and shame. They sober up and face the consequences of their actions. However, the weight of these feelings forces them to seek comfort in substances.
Loss of Interest. Loss of interest in activities you used to enjoy is a key symptom of both addiction and depression, but overcoming the former makes it much easier to gain control over the latter. It’s such a destructive symptom because of how demotivating it is to feel there’s no joy in the world. Everyone has passions and interests, but getting back to finding them isn’t easy for someone with these conditions [11-20].

Management of Substance Abuse

According to APA (2018), The management includes:

Pharmacologic Management

Pharmacologic management in substance abuse has two main purposes:

To permit safe withdrawal from substance of abuse and
To prevent relapse.

The drugs that consist the pharmcological intervention include:

alcohol withdrawal is usually managed with benzodiazepine-anxiolytic agent, which is used to suppress the symptoms of abstinence.
Disulfiram (antabuse). This may be prescribed to help deter clients from drinking.
Acamprosate (campral). This may be prescribed for clients recovering from alcohol abuse or dependence to help reduce cravings for alcohol and decrease the physical and emotional discomfort that occurs especially in the first few months of recovery.
It is a potent synthetic opiate used as a substitute for heroine in some maintenance programs.
it is a narcotic analgesic whose only purpose is the treatment of opiate dependence.
Naltrexone: It is an opioid antagonist often used in the treatment of overdose

1. Public Health approach: This Includes

Primary Level Management/Prevention

Creating awareness about substance abuse and their adverse consequences through aid of appropriate mass media tools delivering customized information suitable to the target audience such as family, schools, workers, religious organization, homes in a sensitive manner, Owing to the impact on all age groups of the society.
Provision of recreational activities for youths in urban areas.
Moral realignment for a derailed person.
Educational approaches targeting parents improving family lifestyle.
Drug education as part of school curriculum.
Screening ( drug screening for undergraduates)

Secondary Level Management

Laboratory tests such as
Blood test
Mean corpuscular volume
Urine drop test
Urinalysis
Detoxification
Treatment of associated mental and physical disorder
Psychotherapy
Cognitive behavioral therapy(CBT)
Family therapy
Maintenance of drug-free behavior such as use of anti-craving drugs

Tertiary Level Management

Occupational rehabilitation
Educational rehabilitation and counseling
Social rehabilitation
Provision of legal aid for abuser in legal dilemma
Social support

2. Psychosocial Supports To Substance Use Disorders

Psychosocial interventions are structured psychological or social interventions used to address substance-related problems. (APA,2022)..They can be used at different stages of drug treatment to identify the problem, treat it, and assist with social reintegration.The psychological aspects of development refer to an individual’s thoughts, emotions, behaviors, memories, perceptions, and understanding. The social aspects of development refer to the interaction and relationships among the individual, family, peers, and community (UNRWA, 2017). Psychosocial interventions can be used in a variety of treatment settings either as stand-alone treatments or in combination with pharmacological intervention. They can be implemented individually or in groups and delivered by a range of health workers. It is also considered to be the foundation of drug and alcohol treatment, especially for substances where pharmacological treatments have not been sufficiently evaluated. It involves the following

Psychological Supports for Substance Abuse Disorders and Addicts

A. Individual Therapy Interventions. The effectiveness of this interventions has been established primarily for alcohol use problems, although they have been applied to patients using other substances as well. The aim of the intervention is to help the patient understand that their substance use is putting them at risk and to encourage them to reduce or give up their substance use. It can range from 5 min of brief advice to 15-30 min of brief counseling. Intensive counseling is especially effective and there is a strong dose-response relation between counseling intensity and quitting success. In general, more the intense the treatment intervention greater is the rate of abstinence.

B. Motivation Interviewing. Motivational interviewing is a collaborative conversation style for strengthening a person’s own motivation and commitment to change. It is used to help people with different types of drug problems. Frequently, individuals are not fully aware of their drug problems or they can be ambivalent about their problems. It is often referred to as a conversation about change and it is used to help assist drug users to identify their need for change which is characterized by an emphatic approach in which the therapist helps to motivate the patient by asking about the pros and cons of specific behaviors, exploring the patient’s goals and associated ambivalence about reaching those goals, and listening reflectively to the patient’s response.

It seeks to address an individual’s ambivalence about their drug problems, as this is considered the main barrier to change.

It follows five stages:

Expressing empathy for the client
Helping the client to identify discrepancies between their behavior and their goals
Avoiding arguments with the patient about their motivations and behaviors
Rolling with the resistance of the patient to talk about some issues
Supporting the patient s sense of self-efficacy

C. Cognitive Bhavioural Therapy. Cognitive behavioral therapy (CBT) is a umbrella term that encompasses cognitive therapy on its own and in conjunction with different behavioral strategies. Cognitive therapy is based on the principle that the way individuals perceive and process reality influences the way they feel and behave. As part of drug treatment, cognitive therapy helps clients to build self-confidence and address the thoughts that are believed to be at the root of their problems. Clients are helped to recognize the triggers for substance use and learn strategies to handle those triggers. Treatment providers work to help patients to identify alternative thoughts to those that lead to their drug use, and thus facilitate their recovery. Generally, cognitive therapy is provided after a client has been diagnosed as having drug dependence problems.

CBT treatment usually involves efforts to change thinking patterns. These strategies might include:

Learning to recognize one’s distortions in thinking that are creating problems, and then to reevaluate them in light of reality.
Gaining a better understanding of the behavior and motivation of others.
Learning to develop a greater sense of confidence in one’s own abilities.
Using role playing to prepare for potentially problematic interactions with others.
Learning to calm one’s mind and relax one’s body.

D. Contingency Management. Contingency management refers to a set of interventions involving concrete rewards for clients who achieve target behaviors. This approach is based around recognizing and controlling the relationship between behaviors and their consequences. It can be applied to drug users with different types of problems in a variety of settings. It has been used, for example, with opioid and cocaine users, and with homeless clients. Contingency management is used to maintain abstinence by reinforcing and rewarding alternative behaviors to drug use with the aim of making abstinence a more positive experience. Contingency management programs can, for example, be used during drug treatment to reward a user remaining abstinent or to incentivize a user’s presence at work in a social reintegration programme.

Social Skills Therapy. Social skills are defined as the ability to express positive & negative feelings in the interpersonal context without suffering loss of interpersonal reinforcement. Social skills training (SST) is a type of behavioral therapyused to improve social skills in people with mental disorders or developmental disabilities. Social skills can be taught, practiced and learned.The main purpose of social skills training is teaching persons who may or may not have emotional problems about the verbal as well as nonverbal behaviors involved in social interactions.

Another goal of social skills training is improving a patient’s ability to function in everyday social situations.

SST Techniques

Behavioral Rehearsal. Role play which involves practicing new skills during therapy in simulated situations
Corrective Feedback. Used to help improve social skills during practice
The educational component of SST that involves the modeling of appropriate social behaviors
Positive Reinforcement. used to reward improvements in social skills
Weekly Homework Assignments. Provide the chance to practice new social skills outside of therapy

E. Family Behavior Therapy (FBT). FBT focuses on how the behaviors of the person with the SUD affect the family as a whole and works to change those behaviors with the involvement of the entire family.Goals of family therapy include obtaining information about the patients and his factors which contribute to substance abuse. These include the patient’s attitude toward substance abuse, treatment adherence, social and vocational adjustment, level of contact with substance using peers, and degree of abstinence. Family support for abstinence, maintaining marital and family relationships are encouraged.Even the brief involvement of family members in the treatment program can enhance treatment engagement and retention.

F. Self Help Groups. Self-help groups are voluntary not-for-profit organizations where people meet to discuss and address shared problems, such as alcohol, drug or other addictions. Participants seek to provide support for each other, with senior members often mentoring or sponsoring new ones. Prominent examples include Alcoholics Anonymous and Narcotics Anonymous, and there is a range of other groups with similar purposes. As well as helping drug users, some self-help groups exist to support the family members of people with alcohol- and drug-related problems. Self-help groups can be used to help people to recognize their drug-related problems and can be a support during drug treatment, and they can help users to maintain abstinence and prevent relapse.

The groups aim to create a drug-free supportive network around the individual during the recovery process and provide opportunities to share experiences and feelings.

H. Therapeutic Communities. Residential rehabilitation programs (sometimes called therapeutic communities) are usually long-term programs where people live and work in a community of other substance users, ex-users and professional staff. Programs can last anywhere between 1 and 24 months (or more). The aim of residential rehabilitation programs is to help people develop the skills and attitudes to make long-term changes toward an alcohol- and drug-free life-style. Programs usually include activities such as employment, education and skills training, life skills training (such as budgeting and cooking), counseling, group work.

Implications

Nursing Education and Practice

Advocacy to focus on strengthening family support system, self help and peer group optimizations.
Creating awareness about substance abuse and their adverse consequences through aid of appropriate mass media tools delivering customized information suitable to the target audience such as family, schools, workers, religious organization, homes in a sensitive manner, Owing to the impact on all age groups of the society.
It is of prime importance to design and formulate an effective community based and a holistic strategy to address the needs of the drug abuser and their family comprehensively. Multiple measures such as identifying the psychosocial determinants that may determine the use of illicit drug, developing family prevention programs in the form of multi-dimensional family therapy and individual cognitive behavioral therapy
Sensitizing clinicians to identify patients at risk for nonprescription drug abuse, strengthening preclinical assessment to predict substance abuse liability, encouraging exercises as a potential treatment for drug abuse and building mechanisms for tracking and monitoring prescription drug abuse.
Formulating strategies in collaboration with international agencies to monitor the sale of over-the-counter drugs and enforcing stricter penalties for individuals who are involved in trade of illicit drugs.
Also, an important role to play in screening the adolescent, youths for drug use during routine medical checkup.

Nursing Research

Collaborate with other health personnel in research study relating to substance abuse thus providing new information in the Psychological care of clients with substance abuse [21-28].

Conclusion

Substance abuse is still a menace and has grown to become global subculture whose effects is cataclysmic and cuts across every society, creed, or race. However, no individual is born an abuser, but the multifarious human activities have through learning, interaction, and curiosity made man to develop this habit. It is empirical that substance abuse is more common amongst the youth especially in Nigeria. The habit develops as an attempt for instance to justify a curiosity in the daily interactions as man is a gregarious animal.

To the individual, its effects can be physiological and psychological, which gradually penetrates the society and affects all productive endeavors both socially and economically. As a menace, substance abuse has habitually become a means to an end which calls for individuals, families, groups, communities, societies and the Nigerian government to collaboratively join hands in curbing the menace. Psychosocial support is presented here as a way out of the menace. Mental health nurses are central to providing the support.

Recommendations

In an attempt to proffer some meaningful solutions to curb the menace of substance abuse, the following recommendations are presented to both government and the society at large.

(a) Government policies targeted at developing the society are more often than not mere paper work. Thus, the government should ensure that through its policies, jobs are created, social services are rendered, and above all, its policies should be feasible and capable of implementation.

(b) Hospitals and clinics should be well stocked with genuine drugs and trained physicians put in place to ensure proper prescription of drugs while monitoring how the patients take such drugs to avoid over or under dosage tendencies which will lead to drug abuse.

(c) There should be a proper scrutiny and licensing of patent medicine stores, and such should be operated by well-trained Pharmacists. Alongside this, street drug hawking should be discouraged since this can promote accessibility to drug abusers.

(d) Individuals, families, communities, and the entire society should ensure that moral values are inculcated in the youths, by joining the government’s fight against the menace.

(e) Implementing a policy of asking patients about their needs an wishes concerning psychosocial supports, as well routinely assessing their levels of psychosocial which may bring about meaningful progress for psychosocial care.

(f) Rehabilitation centers such as therapeutic and penal institutions should be equipped, employ trained staff as well as involve in proper guidance and counseling.

(g) Institutions like the National Drugs Law Enforcement Agency (NDLEA) and the National Agency for Food and Drug Administration and Control (NAFDAC) should be empowered to squarely deal with “Drug Barons” as well their traffickers, peddlers, and conduits. This is because at times, their performances are undermined by the threats they get as well as the purported connections such barons and the traffickers have with people in higher authority.

(h) Government should encourage even development at all levels by providing the required skills, social services and recreational facilities to reduce Rural-Urban migration, as it was also found that so many youths migrate from rural areas to urban areas to search for the greener pastures and facilities lacking in the rural areas.

(i) Non-Governmental Organizations (NGOs) and Community Based Organizations (CBOs) should encourage the sensitization campaigns against drug abuse as well as engage in rehabilitation programs.

(j) Educational Institutions at all levels whether public or private should organize workshops, lectures/ symposiums to enlighten the people on the dangers of drugs and substance abuse.

References

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Numerical Simulation of Surface and Internal Wave Excitation due to an Air Pressure Wave

1 Reply

DOI: 10.31038/GEMS.2023533

Abstract

The excitation of surface and internal water waves by an air pressure wave has been numerically simulated in several model cases, using a nonlinear shallow water model of velocity potential. Water waves were excited when the air pressure wave speed was close to the water wave speed in the surface mode or internal mode. The surface mode waves traveling as free waves after being excited by an air pressure wave were also amplified by the shallowing on a sloping seabed. When the air pressure wave with a speed close to that of the internal mode stopped, free surface waves in the internal mode hardly appeared, unlike the free internal waves.

Keywords

Surface wave, Internal wave, Air pressure wave, Proudman resonance, Nonlinear shallow water

Introduction

Internal waves in various waters, such as the East China Sea, e.g., [1,2], and Lake Biwa, e.g., [3,4], may gain large wave heights because the density ratio in water is not as large as that of surface waves. Although various sources of internal waves—tidal currents [5], wind- driven near-inertial waves [6], etc.—have been revealed, the causes of internal waves are unknown in many actual waters.

In the present study, we consider surface/internal wave excitation due to an air pressure wave. Regarding surface waves, air pressure waves of a few hectopascals often generate meteotsunamis around the world, e.g., [7,8,9]. For example, at the west coasts of Kyushu, Japan, meteotsunamis called “Abiki” are observed, e.g., [10,11]. Conversely, internal waves are also generated and amplified by air pressure waves due to meteorological factors including typhoons [12,13]. The excitation mechanism underlying these phenomena is the Proudman resonance [14], which is also known as the cause of other transient waves, e.g., [15,16,17,18,19]. Moreover, the resonance triggered by air pressure waves from a volcanic eruption may generate global tsunamis, e.g., [20,21]. Artificial waves can also be created by the resonance when an airplane moves on a very large floating airport [22].

In this basic research, numerical simulations of surface and internal wave excitations due to an air pressure wave have been generated in several model cases, using a nonlinear shallow water model of velocity potential. Although the wave dispersion and Coriolis force are not considered, the proposed simple model will provide an easy-to-use tool for predicting long-wave excitations from air pressure changes estimated in weather forecasts. We consider the cases in which the air pressure wave speed is close to the surface or internal mode speed.

Method

We consider the irrotational motion of inviscid and incompressible fluids in two layers, as illustrated in Figure 1.

Figure 1: Two-layer water

The still water depths of the upper and lower layers are h₁(x) and h₂(x), respectively, and h(x) = h₁(x) + h₂(x). We assume that the densities of the upper and lower layers, ρ₁ and ρ₂, respectively, are uniform and constant, and that the fluids do not mix even in motion. The water surface displacement, interface displacement, and seabed position are denoted by ζ(x, t), η(x, t), and b(x), respectively. Friction is ignored everywhere for simplicity. The velocity potentials of the upper and lower layers are ϕ₁(x, t) and ϕ₂(x, t), respectively.

The nonlinear shallow water equations of velocity potential considering the pressure on the water surface, p₀(x, t), are

Upper Layer

∂η/∂t = ∂ζ/∂t + ∇[(ζ – η) ∇ϕ₁], (1)

∂ϕ₁/∂t = – [gζ + p₀/ρ₁ + (∇ϕ₁)²/2], (2)

Lower Layer

∂η/∂t = –∇ [(η – b) ∇ϕ₂], (3)

∂ϕ₂ /∂t = – [gη + (p₁ + P₂ )/ρ₂ + (∇ϕ₂ )²/2], (4)

where ∇ = (∂/∂x, ∂/∂y) is a horizontal partial differential operator. The gravitational acceleration g is 9.8 m/s², p₁(x, t) is the pressure at the interface, and P₂ = (ρ₂ – ρ₁)gh₁. Equations (1)–(4) can be derived by reducing the nonlinear equations based on the variational principle [23].

Substituting Equation (3) into Equation (1), we obtain

∂ζ/∂t = – {∇ [(ζ – η) ∇ϕ₁] + ∇ [(η – b) ∇ϕ₂]}. (5)

In the upper layer, reversing the direction of the integration with respect to z gives the following auxiliary equation as

∂ϕ₁/∂t + gη + p₁/ρ₁ + (∇ϕ₁)²/2 = 0, (6)

which corresponds to the Bernoulli equation on z = η.

By substituting Equation (2) into Equation (6), we obtain

p₁ = p₀ + ρ₁ g(ζ – η), (7)

which expresses the hydrostatic pressure distribution. By substituting Equation (7) into Equation (4), we obtain

∂ϕ₂/∂t = – [gη + p₀/ρ₂ + r^-1g(ζ – η) + (1 – r^-1)gh₁ + (∇ϕ₂)²/2], (8)

where r = ρ₂/ρ₁ > 1.

By eliminating p1 from Equations (4) and (6), we obtain

∂ϕ₁/∂t – r∂ϕ₂ /∂t = (r – 1)g(η + h₁) – [(∇ϕ₁ )² – r(∇ϕ₂)²]/2. (9)

We explicitly solve the above equations using a finite difference method with the central difference in space and the forward difference in time. When the pressure at the water surface, p₀, is known and the water surface displacement ζ is unknown, the procedure shown in

Figure 2 is repeated, starting from the initial still water state, to obtain new time-step values one after another.

Figure 2: Procedure for obtaining the surface displacement ζ，interface displacement η, and velocity potentials in the upper and lower layers, ϕ₁ and ϕ₂, respectively, when the pressure at the water surface, p₀, is given.

Conversely, when the pressure at the water surface, p₀, is unknown and the water surface displacement ζ is known, we adopt the procedure shown in Figure 3, which was not used in the present calculations.

Figure 3: Procedure for obtaining the interface displacement η and velocity potentials in the upper and lower layers, ϕ₁ and ϕ₂, respectively, when the surface displacement ζ is given.

Conditions

Focusing on one-dimensional wave propagation in the x-axis direction, we assumed that a steady air pressure wave W, as sketched in Figure 4, traveled in the positive direction of the x-axis with a constant speed v_P. The waveform of the air pressure wave was an isosceles triangle, where the length of its base, i.e., the wavelength λ, was 10 km or 20 km. The maximum and minimum pressures p_m of positive and negative air pressure waves, respectively, were 2hPa and −2 hPa, respectively, referring the values in the meteotsunami and eruption cases [11,21]. The position of the air pressure wave center at the initial time, i.e., t = 0 s, was x₀ = 50 km.

Figure 4: Waveform of the steady air pressure wave W at the initial time, i.e., t = 0 s. The air pressure wave traveled in the positive direction of the x-axis with constant speed v_p.

The densities of the upper and lower layers were ρ₁ = 1000 kg/m³ and ρ₂ = 1025 kg/m³, respectively. Both the initial velocity potentials ϕ₁(x, 0 s) and ϕ₂(x, 0 s) were 0 m²/s. The grid width Δx was 250 m and the time step interval Δt was 1 s.

Excitation of the Surface Mode

In Figure 4, the wavelength λ and the maximum pressure p_m of the air pressure wave were 10 km and 2 h Pa, respectively. In the initial still water state, the total water depth h was 5000 m and the upper layer depth h₁ was 1000 m, in Figure 1. For linear shallow water waves, the phase velocity of the surface mode, C_s, is √(gh) ≃ 220 m/s. When the traveling velocity of the air pressure wave, v_p, is 207 m/s, which is close to C_s, the time variations of the air pressure distribution and both the surface and interface profiles are depicted in Figure 5, in which the results for 100 s ≤ t ≤ 1000 s are displayed every 100 s.

Figure 5: Time variations of the air pressure distribution, surface profile, and interface profile every 100 s. The still water depth h was 5000 m and the still water depth ratio h₁/h was 0.2. The wavelength λ, maximum pressure p_m, and speed v_p of the air pressure wave were 10 km, 2 hPa, and 207 m/s, respectively.

Figure 5 indicates that the crests and troughs in the surface mode were excited by the Proudman resonance not only at the surface but also at the interface, because the positions of the surface and interface were relatively close. When t = 100 s, the water wave crests have been generated at the air pressure rise, whereas the water wave troughs at the air pressure fall. The length of the water wave crests and troughs was approximately half the wavelength of the air pressure wave. Thereafter, the water wave crests gradually led away from the air pressure wave because the surface mode speed was greater than the air pressure wave speed. When t = 1000 s, the water wave crests were propagating as free waves, whereas the water wave troughs have been constrained by the air pressure wave, and the wavelength of each crest and trough was approximately the same as that of the air pressure wave.

When the seabed is partially sloping, Figure 6 depicts the numerical results for the same conditions as in the case above, except for the topography, where the seabed position b is described as

b = −5000 m for 0 ≤ x < 150 km,

b = −3500 m − 1500 m × cos π (x/150 km – 1) for 150 km ≤ x ≤ 300 km. (10)

Figure 6: Time variations of the air pressure distribution, surface profile, and interface profile every 100 s. The seabed profile is also depicted, where the seabed position b is described by Equation (10). The initial water depth in the upper layer, h₁ was 1000 m. The wavelength λ, maximum pressure p_m, and speed v_p of the air pressure wave were 10 km, 2 hPa, and 207 m/s, respectively.

As indicated in Figure 6, the second peaks of water wave crests were generated when the air pressure wave speed approached the surface mode speed on the slope. Moreover, both the water wave crests and troughs were amplified by shallowing on the slope after they moved away from the air pressure wave. It should be noted that the shallowing effect requires water waves that are traveling as free waves apart from the air pressure waves that excited the water waves. When an eruption creates air pressure waves with different speeds, as in the case of the 2022 Hunga Tonga–Hunga Ha`apai volcanic eruption, the air pressure waves excite tsunamis at water depths corresponding to the air pressure wave speeds [24], and each tsunami traveling apart from the air pressure wave that excited it can be amplified by shallowing on a ridge, shelf slope, continental shelf, etc. Tsunamis traveling as free waves after being excited by air pressure waves may also be amplified by being passed by subsequent air pressure waves over topography [21], as indicated in the water wave crests at t = 1000 s in Figure 6. Moreover, bay oscillations, currents, and horizontally two-dimensional changes in topography may amplify tsunamis, similar to submarine earthquake tsunamis.

Excitation of the Internal Mode

The wavelength λ and the maximum pressure p_m of the air pressure wave were 10 km and 2 hPa, respectively, in Figure 4. The still water depth h was uniformly 5000 m, and the still water depth ratio h₁/h was 0.2, in Figure 1. The internal mode speed for linear shallow water waves without surface waves is

so C_i ≃ 14 m/s in the present case. We assumed that while 0 s ≤ t < 1000 s, the air pressure wave speed v_p was 14 m/s, which was almost equal to C_i, whereafter the air pressure wave stopped at t = 1000 s, and the air pressure distribution was stagnated for t ≥ 1000 s. The time variations of the air pressure distribution and both the surface and interface profiles are depicted in Figure 7, in which the results for 200 s ≤ t ≤ 2000 s are displayed every 200 s.

Figure 7: Time variations of the air pressure distribution, surface profile, and interface profile every 200 s. The still water depth h was 5000 m and the still water depth ratio h₁/h was 0.2. The wavelength λ, maximum pressure p_m, and speed v_p of the air pressure wave were 10 km, 2 hPa, and 14 m/s, respectively.

Based on Figure 7, the internal waves in the internal mode were excited by the Proudman resonance, and especially the crest was amplified remarkably. Conversely, free surface waves in the internal mode hardly appeared because the surface wave crest was constrained by the stagnant air pressure distribution.

When the wavelength λ and the minimum pressure p_m of the air pressure wave are 20 km and −2 hPa, respectively, Figure 8 presents the numerical results for the same other conditions as in the above case.

Figure 8: Time variations of the air pressure distribution, surface profile, and interface profile every 200 s. The still water depth h was 5000 m and the still water depth ratio h₁/h was 0.2. The wavelength λ, minimum pressure p_m, and speed v_p of the air pressure wave were 20 km, −2 hPa, and 14 m/s, respectively.

In Figure 8, the waveform of the generated internal waves propagating as free waves is different from the vertically inverted waveform of the above-mentioned internal waves due to the air pressure wave of positive pressure, disregarding the difference in wavelength. Therefore, future work is required to investigate the stability of the upward and downward convex internal waves due to an air pressure wave, considering higher-order terms of the velocity potential.

Conclusion

The excitation of surface and internal water waves by an air pressure wave was numerically simulated using the nonlinear shallow water model of velocity potential. The water waves were excited when the air pressure wave speed was close to the water wave speed in each mode. The surface mode waves traveling as free waves after being excited by an air pressure wave were also amplified by the shallowing on the sloping seabed. When the air pressure wave, the speed of which was close to the internal mode speed, stopped, free surface waves in the internal mode hardly appeared, unlike the free internal waves.

In the present model, wave dispersion is ignored, so in the future, the excitation of relatively shorter water waves by air pressure waves should be investigated using a numerical model with higher-order terms of velocity potential.

Conflicts of Interest

The author declares no conflict of interest.

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Double Cote’s Spiral in M83 Galaxies, NGC 1566 and Cyclone in the South Georgia and South Sandwich Islands

8 Replies

DOI: 10.31038/GEMS.2023532

One comparative analysis of the shape of spiral galaxies and the subtropical cyclone that formed north of Georgia Island and passed north of the South Sandwich Islands, in the South Atlantic Ocean. Subtropical cyclones with double spirals appear to be common in these areas of the South Atlantic. A subtropical cyclone is a weather system that has some characteristics of a tropical cyclone and some characteristics of an extratropical cyclone. They can form between the equator and the 50th parallel. In mathematics, a spiral is a curve, which emanates from a point, moving farther away as it revolves around the point. The characteristic shape of hurricanes, cyclones, typhoons is a spiral. The characteristic equation of which spiral the Extratropical Cyclone (EC) Its double spiral shape, whose mathematical equation has already been deﬁned as Cote’s spiral, Gobato et al. (2022) and similarly Lindblad (1964) show shape of double spiral galaxies, already studied among others is discussed here [44].

The South Georgia Group lies about 1,390 km (860 mi; 750 mi) east-southeast of the Falkland Islands, at 54°-55°S, 36°-38°W. It comprises South Georgia Island itself by far the largest island in the territory, and the islands that immediately surround it and some remote and isolated islets to the west and east-southeast. It has a total land area of 3,756 square kilometers (1,450 sq. mi), including satellite islands, but excluding the South Sandwich Islands, which form a separate island group [53,56]. A cyclone is a large air mass that rotates around a strong center of low atmospheric pressure, counterclockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere as viewed from above (opposite to an anticyclone) [1–4,27,29]. A subtropical cyclone is a weather system that has some characteristics of a tropical cyclone and some characteristics of an extratropical cyclone. They can form between the equator and the 50th parallel [1–9,26,27].

These storms usually have a radius of maximum winds that is larger than what is observed in purely tropical systems, and their maximum sustained winds have not been observed to exceed about 32 m/s (64 knots). Subtropical cyclones sometimes become true tropical cyclones, and likewise, tropical cyclones occasionally become subtropical storms. Subtropical cyclones in the Atlantic basin are classiﬁed by their maximum sustained surface winds: Subtropical depressions have surface winds less than 18 m/s (35 knots), while subtropical storms have surface winds greater than or equal to 18 m/s [9–21,26,27,29].

In mathematics, a spiral is a curve, which emanates from a point, moving farther away as it revolves around the point [23–25]. The characteristic shape of hurricanes, cyclones, typhoons is a spiral [26,27,29,34–41]. There are several types of turns, and determining the characteristic equation of which spiral the cyclone bomb (CB) [28] ﬁts into is the goal of the work. Spiral galaxies form a class of galaxy originally described by Edwin Hubble in his 1936 work The Realm of the Nebulae and, as such, form part of the Hubble sequence. Most spiral galaxies consist of a ﬂat, rotating disk containing stars, gas and dust, and a central concentration of stars known as the bulge. These are often surrounded by a much fainter halo of stars, many of which reside in globular clusters [54].

The core of cyclone presents the form of a double spiral, Figure 1, in the same way the study of the spiral of the galaxies of Lindblad, (1964) [32]. This spiral is denoted from Cotes Spiral Gobato et al. (2000) [7–11,18–20,22–25,44].

Figure 1: Image of Georgia, scale 1:200, on April 11, 2003, PM, and nucleus at the coordinates given in the image [46] [Authors].

The very ﬁne image quality of this camera, coupled with the huge light-collecting power of the VLT, reveals vast numbers of stars within the galaxy. The images were taken in three different parts of the infrared spectrum and the total exposure time was eight and a half hours, split into more than ﬁve hundred exposures of one minute each. The ﬁeld of view is about 13 arcminutes across [49,55].

The Figure 2 show Hubble image captures hundreds of thousands of individual stars, thousands of star clusters and hundreds of supernova remnants in the spiral galaxy M83. Also known as the Southern Pinwheel, this galaxy is located 15 million light-years away from Earth in the constellation Hydra. It was discovered in 1752 by the French astronomer Nicolas Louis de Lacaille. With an apparent magnitude of 7.5, M83 is one of the brightest spiral galaxies in the night sky. It can be observed using a pair of binoculars most easily in May [49,50].

Figure 2: Spectacular spiral galaxies using the impressive power of the HAWK-I [49,50]

NGC 1566, sometimes known as the Spanish Dancer, is an intermediate spiral galaxy in the constellation Dorado, positioned about 3.5° to the south of the star Gamma Doradus (Figure 3). It was discovered on May 28, 1826 by Scottish astronomer James Dunlop. At 10th magnitude, it requires a telescope to view. The distance to this galaxy remains elusive, with measurements ranging from 6 Mpc up to 21 Mpc [50,51]. The small but extremely bright nucleus of NGC 1566 is clearly visible in this image, a telltale sign of its membership of the Seyfert class of galaxies. The centers of such galaxies are very active and luminous emitting strong bursts of radiation and potentially harboring supermassive black holes that are many millions of times the mass of the sun [50,51].

Figure 3: Hubble image shows NGC 1566, a beautiful galaxy located approximately 40 million light-years away in the constellation of Dorado (The Dolphinﬁsh). NGC 1566 is an intermediate spiral galaxy, meaning that while it does not have a well-deﬁned bar-shaped region of stars at its center like barred spirals it is not quite an unbarred spiral either [50,51].

NGC 1566 is not just any Seyfert galaxy; it is the second brightest Seyfert galaxy known. It is also the brightest and most dominant member of the Dorado Group, a loose concentration of galaxies that together comprise one of the richest galaxy groups of the southern hemisphere. This image highlights the beauty and awe-inspiring nature of this unique galaxy group, with NGC 1566 glittering and glowing, its bright nucleus framed by swirling and symmetrical lavender arms [50,51].

NGC 1566 is an intermediate spiral galaxy, meaning that while it does not have a well-deﬁned bar-shaped region of stars at its center like barred spirals it is not quite an unbarred spiral either [50,51]. The Figure 1 show the image of Georgia, scale 1:200, on April 11, 2003, PM, and nucleus at the coordinates given in the image. The Georgia, on April 11, 2003, PM and nucleus at the coordinates given in the image. The of Georgia, in an atmospheric pressure gradient model generated by the Zoom Earth system, on April 11, 2003, 12:30, with 951 mbar, and whose core was located at approximate coordinates of image. The image of Georgia, in surface wind model generated by the Zoom Earth system, on April 11, 2003, 12:00, with 5 km/h WSW, and nucleus at the coordinates given in the image.

The model of wind currents for the displacement of air masses observed in the images is consistent with that observed which presents a great turbulence in the vortex. The highlighted cyclone vortex still in turbulent formation presents two linear containment barriers, in an L shape. The subtropical cyclone that formed northwest of South Georgia and South Sandwich Island is here called Georgia. It moved 237 km in 12 h towards the West, when it was 589 km from South Georgia Island, to 809 km from the center of the coast of the South Georgia Island. During this time interval, it maintained an atmospheric pressure at sea level at its vortex close to 951 hPa. It presented rotational winds of 5 km/h approximately 8 km from the central vortex (Figure 4).

Figure 4: Image of Georgia, scale 1:100, in surface wind model generated by the Zoom Earth system, on April 11, 2003, 12:00, with 5 km/h WSW, and nucleus at the coordinates given in the image.

The analogous shape of Georgia and the galaxies Messier 83 and NGC 1566, studied here, is clear. These present a double spiral, as studied by Lindblad [47], but with the Cote’s spiral form, Gobato et al. (2022) [8,9,11] (Table 1).

Table 1: Subtropical Cyclone Georgia: Location/Pressure

April 11, 2023	Coordinates	Pressure (hPa)
AM	53◦13’09”S 27◦45’05”W	951
PM	53◦16’42”S 24◦00’38”W	951

The subtropical cyclone that formed northwest of South Georgia & South Sandwich Island is here called Georgia. It moved 237 km in 12 h towards the West, when it was 589 km from South Georgia Island, to 809 km from the center of the coast of the South Georgia Island. During this time interval, it maintained an atmospheric pressure at sea level at its vortex close to 951 hPa. It presented rotational winds of 5 km/h approximately 8 km from the central vortex. With an approximate dimension of 1,000,000 km², and an area of direct inﬂuence of 3,500,000 km², the subtropical cyclone Georgia moved at an average speed of 19.75 km/h.

The mathematical model for the atmospheric pressure gradient used by ZoomEarth [43] matches the correct way to scale the atmospheric pressure, as can be seen in the comparison of the satellite images. The model of wind currents for the displacement of air masses observed in the images is consistent with that observed in which presents a great turbulence in the vortex. The image of Georgia, scale 1:20, on April 11, 2003, PM and nucleus at the coordinates given in the image. The image of Georgia, on a 1:100 scale, in an atmospheric pressure gradient model generated by the Zoom Earth system, on April 11, 2003, 12:30, with 951 mbar, and whose core was located at approximate coordinates of image, and image of Georgia, scale 1:100, in surface wind model generated by the Zoom Earth system, on April 11, 2003, 12:00, with 5 km/h WSW, and nucleus at the coordinates given in the image. The highlighted cyclone vortex still in turbulent formation presents two linear containment barriers, in an L shape. The have Georgia’s double spiral Cote’s shape. The analogous shape of Georgia and the galaxies Messier 83 and NGC 1566, studied here, is clear. These present a double spiral, as studied by Lindblad (1964) [47], but with the Cote’s spiral form, Gobato et al. (2022) [8,9,11,44].

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Significant of Molecular Genotyping Over Serological Phenotyping Techniques in Determination of Blood Group Systems among Multiple Transfused Patients and Blood Donors to Prevent Alloimmunization: A Review Article

6 Replies

DOI: 10.31038/CST.2023821

Summary

Erythrocyte serological phenotyping is very important in determining the identity of suspected alloantibodies and also to facilitate the identification of antibodies that may be formed in the future. Serological phenotyping is a conventional method which is based on the presence of visible haemagglutination or haemolysis. This technique has some limitations in successful determination of blood group due to presence of donor red blood cell in the circulation of recent multiple transfused patients, taking certain medications or some diseases condition which may alter the erythrocyte composition, this make accurate determination of blood group of such patients to be time consuming and difficult to interpret. It is often more complicated to determine the blood group if direct antiglobulin test of such patients were positive and there is no direct agglutinating antibody. Molecular Genotyping of blood group systems led to the understanding of the molecular basis of many blood group antigens, many blood group polymorphisms are associated with a single point mutation in the gene encoding of protein carrying the blood group antigen. This knowledge allows the use of molecular testing to predict the blood group antigen profile of an individual and to overcome the limitations of conventional serological blood group phenotyping. Determination of blood group polymorphism at the genomic level facilitates the resolution of clinical problems that cannot be addressed by serological techniques. Applications of blood group genotyping for red cell blood group antigens affecting several areas of medicine which includes identification of fetuses at risk for haemolytic disease of the newborn and candidates for Rh-immune-globulin, to determine antigen types for which currently available antibodies are weakly reactive, to determine blood group of patients who had recent multiple transfusion, to increase the reliability of repositories of antigen negative RBCs for transfusion, to select appropriate donor for bone marrow transplantation, to provide transfusion support for highly alloimmunized patients, to resolve ABO and Rh discrepancies, to conﬁrm sub group of A₂ status of kidney donors, to provide comprehensive typing for patients with haematological diseases requiring chronic transfusion and oncology patients receiving monoclonal antibody therapies that interfere with pretransfusion testing.

Keywords

Molecular, Serological, Red cell antigens, Alloantibodies and transfusion

Introduction

Blood group systems are characterized by the presence or absence of antigens on the surface of erythrocytes, the specificity of antigens is controlled by a series of genes which can be allelic or linked very closely on the same chromosome which persist throughout life and serve as identity markers. Presently, International Society of Blood Transfusion (ISBT) has acknowledged about 36 blood group systems and more than 420 blood group antigens have been discovered on the surface of the human red cell (Storry et al., 2016). The clinical importance of RBC antigens is associated with their ability to induce alloantibodies that are capable of reacting at 37⁰C (body temperature), these antibodies have ability to cause destruction of erythrocytes. The major clinically significant antibodies include ABO, Rh, Kell, Kidd and Duffy antigens (Karafin et al., 2018). ABO antibodies are naturally occurring antibodies, while Rh and Kell antibodies are immunogenic in nature. The immune system produces alloantibodies when it is exposed to foreign antigens (incompatible erythrocyte) these antibodies form a complex with donor cells causing haemolytic transfusion reactions. Patients with Rh and Kell alloantibodies should be transfused with blood that is lacking the antigens because these antibodies are capable of causing severe haemolytic anaemia and haemolytic disease of the newborns (Singhal et al., 2017). Hence, it is important to transfused females of child-bearing age with compatible blood in order to reduce or minimize the possibility of sensitizing their immune system with clinically important antigens (Guelsin et al., 2015). Unexpected incompatibility reactions are the major risks of blood and blood products transfusion apart from transfusion transmissible infections, clinically significant alloantibodies play a critical role in transfusion medicine by causing either acute or delayed haemolytic transfusion reactions (HTRs) and haemolytic disease of the fetus and newborn (HDFN) ranging from mild to severe grades. The degree of production of alloantibodies that is capable of destroy foreign or donor red cells is higher amongst multi-transfused patients compared with general population (Karafin et al., 2017). Serological phenotyping of blood group system is a classical and conventional method of detecting erythrocyte antigen by haemagglutination or haemolysis, accurate phenotyping of blood group system among multi-transfused patients is a very complex process due to the presence of donor’s blood cells in the patient’s circulation except serological phenotyping of blood group system is performed before the initiation of transfusion. Blood group genotyping has recently been developed to determine the blood group antigen profile of an individual, with the goal of reducing risk or identifying a fetus at the risk of haemolytic disease of the newborn (HDN). Blood group genotyping improve the accuracy of blood typing where serology alone is unable to resolve red cell serological phenotyping especially in individuals with weak antigen expression due to presence of genetic variants or in case of rare phenotype where antisera are unavailable or in the case of recent multiple blood or blood products transfusion, or in patients whose RBCs are coated with immunoglobulin (Ye et al., 2016). Genotyping technique also help to determine which phenotypically antigen-negative patients can receive antigen-positive RBCs, to type donors for antibody identification panels, to type patients who have an antigen that is expressed weakly on RBCs, to determine Rh D zygosity, to mass screen for antigen-negative donors, ability to routinely select donor units antigen matched to recipients apart from ABO and Rh D which reduce complications in blood and blood products transfusion (Guelsin et al., 2010). The growth of whole-genome sequencing in chronic disease and for general health will provide patients’ comprehensive extended blood group proﬁle as part of their medical record to be used to inform selection of the optimal transfusion therapy (Connie and Westhoff, 2019). DNA-based genotyping is being used as an alternative to serological antibody-based methods to determine blood groups for matching donor to recipient because most antigenic polymorphisms are due to single nucleotide polymorphism changes in the respective genes. Importantly, the ability to test for antigens by genetic technique where there are no serologic reagents is a major medical advance and breakthrough to identify antibodies and ﬁnd compatible donor units, which can be lifesaving. The molecular genotyping of blood group antigens is an important aspect and is being introduced successfully in transfusion medicine. Genotyping has been shown to be effective and advantageous in relation to phenotype from genomic DNA with a high degree of precision (da Costa et al., 2013) A notable advantage of molecular testing is its ability to identify variant alleles associated with antigens that are expressed weakly or have missing or altered epitopes, thus helping to resolve discrepant or incomplete blood group phenotyping. The disadvantages of molecular testing are mainly the longer turnaround time and higher cost, compared with serologic typing (Marilia et al., 2019). The molecular basis for most erythrocyte antigens is known and numerous DNA analysis methodologies have been developed, all based on PCR which can detect several alleles simultaneously as long as the alleles studies have products of different sizes (Swati et al., 2018). The detection of blood group antigens is essential in transfusion practice in order to prevent alloimmunization, especially in multiple transfused patients. Erythrocyte antibodies that are clinically significant in transfusion medicine can lead to acute or delayed blood transfusion reactions and haemolytic disease of the fetus and newborn which increases the morbidity and mortality rate of the patients. In addition, alloimmunization may delay the localization of a compatible blood bag. The probability of an individual producing one or more anti-erythrocyte antibodies is approximately 1% per unit of blood transfused and in chronically multiple transfused patients, the alloimmunization rate may reach 50%. Both the blood donors and recipients can be genetically typed for all the clinically significant blood group antigens and antigen-matched blood can be provided to the recipient (Guelsin et al., 2010). This approach could significantly reduce the rate of alloimmunization.

Serological Phenotyping

Knowledge of the role of blood groups with their antigens and variants in alloimmunization was pivotal for the development of transfusion practices and medical interventions that require blood transfusion such as trauma, organ transplantation, cancer treatment, haematological diseases (like sickle cell disease, thalassaemia, and aplastic anemia). Serology has been considered the gold standard technique for blood group typing for a long time (Yazdanbakhsh et al., 2014). Serological methods detect the antigen expressed on the red cell using specific antibodies and can be carried out manually or by automated platforms. Typing blood group antigens using this method is easy, fast, reliable, and accurate for most of the antigens. However, serology has limitations, some of which cannot be overcome when it is used as a standalone testing platform (Das et al., 2020). Scarcity of serological reagents for some blood group systems for which there is no monoclonal antibody available is a major limitation to serological technique. In addition, human serum samples from different donors vary in reactivity, which is an issue when a nearly exhausted batch of reagent needs to be replaced. This is especially problematic when an alloantibody for that antigen is suspected to be causing adverse events after transfusion. In those circumstances, molecular methods can be used as an alternative or as a complementary test for identification of genes associated with the blood group antigens expression and prediction of antigenic profile.

Molecular Genotyping

The identification of genes that encode proteins carrying blood group antigens and the molecular polymorphisms that result in distinct antigenicity of these proteins is possible using molecular typing methods, which facilitate blood typing resolution in complex cases and overcome limitations of serological techniques when dealing with allo-immunized and multi-transfused patients (da Costa et al., 2013). In addition, molecular techniques have allowed identification of genes encoding clinically relevant antigens where serological reagents are not available. In those instances, genotyping is critical to resolve clinical challenges. Blood group genotyping is performed to predict blood group antigens by identifying specific polymorphisms associated with the expression of an antigen (Connie and Westhoff, 2019). Most variations in the blood group antigens are linked to point mutations, but for some, other molecular mechanisms are responsible, such as deletion or insertion of a gene, an exon or a nucleotide sequence (for example ABO, RH, and DO blood group systems), sequence duplication, (for example RHD gene and GE blood group system), nonsense mutation (for example RHD gene), and hybrid genes (for example RH, MNS, ABO, and CH/RG blood group systems) (Bakanay et al., 2013). In contrast to serological technique, molecular genotyping tests are performed on DNA obtained from nucleated cells and are not affected by the presence of donor’s red cells in patient’s sample, which is a common occurrence in samples of patients with recent multiple blood and blood products transfusions. Thus, erythrocyte genotyping can resolve blood group typing discrepancies in multi-transfused patients presenting with mixed field reactions, alloantibodies, or autoantibodies. Also, blood group genotyping can substantially help patients who were not previously phenotyped and need regular transfusions by facilitating management of these patients and preventing alloimmunization (Guelsin et al., 2015). Studies comparing serology and genotyping in multi-transfused population such as patients with thalassaemia and sickle cell disease have shown that genotyping is superior to serology for resolving discrepancies. Use of genotyped matched units has been shown to decrease alloimmunization rates, increase haemoglobin levels and in vivo erythrocyte survival, and diminish frequency of transfusions.

Erythrocyte Antigen Disparity and its significant in Transfusion Medicine

Patients who develop alloantibodies might have been received significantly multiple transfusions, or due to pregnancy making alloimmunization a particular problem for such patients especially those requiring chronic RBC transfusion support as a result of haematological diseases (Ngoma et al., 2016). Incidence of alloimmunization is highly variable between individual patients’ health condition, rate of exposure to a foreign antigen, ethnicity and geographical area. However, Knowledge of the genotypes of both patients and donors has led to a greater understanding of potential mechanisms for persistent alloimmunization despite serologic antigen matching for transfusion, also extended matching to include the Duffy, Kidd, and MNS systems has been shown to reduce the rate of alloimmunization (Jenna and Meghan, 2018). It is therefore clear that serologic phenotyping is inadequate to capture allelic diversity in minority populations. Without accurate characterization of the patient and donor genotypes, true antigen matching to prevent alloimmunization is not possible (Chou et al., 2013). In addition, there is still an inadequate understanding of the risk of alloimmunization with specific blood group gene haplotypes, particularly for RHD. Large, multi-institutional studies with genotyping of both patient and donor and better characterization of the specificity of antibodies formed are needed to clarify the clinical significance and immunogenic risks of variant alleles (Putzulu et al., 2017).

Blood Transfusion and Risk of Erythrocyte Alloimmunization

Erythrocyte alloimmunization is a serious adverse event of blood and blood products transfusions which can cause further clinical problems in the recipient patients including worsening of anaemia, development of autoantibodies, acute or delayed haemolytic transfusion reactions, bystander haemolysis, organ failure, and cause serious complications during pregnancies (Singhal et al., 2017). Frequent transfusions can lead to the production of multiple alloantibodies, which is often associated with autoantibodies requiring extensive serological workups and additional transfusions for proper treatment, increasing time and resources to find compatible RBC units (Yazdanbakhsh et al., 2014). Reported erythrocyte alloimmunization rates have considerable variations depending on the population and disease studied. The rates are estimated between 1 and 3% in patients that receive episodic transfusions, while for patients who receive chronic blood transfusions like patients with sickle cell disease, rates vary between 8 and 76% (Chou et al., 2013). The development of RBC antibodies is influenced by many factors including recipient’s gender, age, and underlying disease. The diversity of the blood group antigen expression among the donor and patient populations contributes substantially to the high alloimmunization rates (Ryder et al., 2014). Studies in sickle cell disease patients have reported that inflammation is associated with higher likelihood of alloimmunization, and it is suggested that the extent of the alloimmune response is higher when RBCs are transfused in the presence of an inflammatory signal. Several studies have suggested that genetic variation in immune-related genes and human leukocyte antigens might be associated with susceptibility to or protection from alloimmunization (Zimring and Hendrickson, 2008).

Consequences of Alloimmunization in Transfusion Medicine

Depending on the antigen and clinical significance of the antibody formed, patients can suffer morbidity and mortality due to an acute or delayed hemolytic transfusion reaction if incompatible blood or blood products are transfused (Jenna and Meghan, 2018). A rare but life-threatening consequence of recurrent transfusions is a hyperhaemolytic reaction which occurs in patients with hemoglobinopathies especially in sickle cell disease patients, the mechanism of hyperhaemolytic reaction in SCD could be a complication of alloimmunization, with possible contribution of an underlying genetic predisposition (Putzulu et al., 2017). The development of RBC alloantibodies also impacts patient care by increasing the cost and time required to find compatible RBC units. Once an RBC antibody is identified, all subsequent transfusions must be negative for that antigen to prevent a delay haemolytic transfusion reaction from a robust secondary immune response (Ngoma et al., 2016). An additional risk for previously sensitized patients is the inability to detect evanesced RBC antibodies at future transfusion events, failure to identify pre-existing antibodies is a significant contributor to haemolytic transfusion reaction. Minority patients may be at greater risk of complications from alloimmunization because the presence of antibodies may not be accurately characterized. One reason is that they are more likely to be negative for high-prevalence antigens (Jenna and Meghan, 2018). Antibodies to high-prevalence RBC antigens will react with all reagent RBCs. This is further complicated if the patient also has a positive direct antiglobulin test (DAT), as patients with SCD frequently do; the antibody to a high-prevalence antigen can then easily be confused with a warm autoantibody (Jain et al., 2016). In addition, because most reagent RBCs are not from minority populations, there is a risk that immunogenic Rh variants and other low-prevalence antigens are not expressed on the reagent RBCs, rendering antibody detection tests false-negative. Genotyping can be particularly useful to clarify antibody specificity, identify if there is a lack of a high-prevalence antigen, and identify appropriate donors.

Prevention of Alloimmunization and Improvement of Transfusion Therapy

Prevention of alloimmunization is desirable for any blood and blood products transfusion. Hence, patients not previously transfused or only having episodic blood transfusions, matching for all clinically significant antigens is not of great concern, but can result in alloimmunization against non-matched antigens (Agrawal et al., 2016). Patients previously transfused, particularly transfusion-dependent patients, the alloimmunization risk is higher and management of alloimmunized patients is of greater concern. Their alloimmunization status, including antigens of low clinical significance, is a critical part of their clinical history that may enable health care providers to take measures to prevent further alloimmunization (Singhal et al., 2017). Antigens have variable immunogenicity and not all blood group antigens are involved with the production of clinically significant antibodies after blood transfusion or pregnancy. Ideally, every blood transfusion should be compatible with the most clinically significant antigens to prevent alloimmunization (Swati et al., 2018). However, the standard pre-transfusion cross-matching is only performed for ABO blood group and the Rh (D) antigen; ABO matching is performed to avoid acute haemolytic transfusion reactions caused by natural IgM antibodies against ABO antigens, and Rh (D) matching is performed because of the high immunogenicity of the Rh (D), which is implicated in delay haemolytic transfusion reaction and haemolytic disease of foetus and newborn (Chou et al., 2013). Currently, recommendations for partial and extended donor unit or patient matching are limited to specific groups including patients on long-term transfusion protocol (sickle cell disease, thalassaemia, and aplastic anemia), patients who have developed alloantibodies and patients with warm autoimmune haemolytic anaemia (Kulkarni et al., 2018). Verification of compatibility for Rh (D, E, C, c, e) and K, which are the most frequent antigens involved in alloimmunization, is considered partial matching. Extended matching should include at least RH (D, C, E, c, e), KEL (K), FY (Fya, Fyb), JK (Jka, Jkb), MNS (S, s) and, if available, additional antigens (Osman et al., 2017). Prevention of an initial alloimmunization event may be even more important than previously appreciated to prevent the development of subsequent antibodies. For patients with a tendency toward forming RBC antibodies, and also having a RBC phenotype with either multiple negative antigens and/or lacking high-prevalence antigens, compatible units may become so rare as to make transfusion support virtually impossible (Wilkinson et al., 2012)

Screening for Clinically Significant Alloantibodies

Alloantibodies are antibodies produced in a patient as a result of exposure to foreign red cell antigen through transfusion of blood or blood products, pregnancy or transplantation (Agrawal et al., 2016). In countries such as Nigeria, there are multiple ethnic groups and racial or genetic heterogeneity among the population. This can often be associated with a wide variation of alloantibodies. Other common factors that facilitate alloantibody formation in the recipient include: the immune competence, the dose of the antigen the recipient is exposed to, the route of exposure and how immunogenic the foreign antigen is (Erhabor et al., 2015). Development of alloantibodies can lead to difficulty in finding compatible blood for transfusion or it can result in severe delayed haemolytic transfusion reaction if the antibody titre is low, undetected, missed and if antigen positive units is transfused. Evidenced-based best practice in the developing world requires that alloantibody testing is carried out as part of pre-transfusion testing of patients who require a red cell transfusion as well as pregnant women presenting to antenatal clinic at booking (Guelsin et al., 2015). The purpose of this test is to detect the presence of unexpected red cell antibody in the patient’s serum. Once these antibodies are detected during the alloantibody screening, every effort must be made to identify the specificity of the alloantibody by doing a panel test. The aim of identifying the specificity of the alloantibody in a patient that requires a red cell transfusion is to enable the Medical Laboratory or Biomedical Scientist to select antigen negative donor unit for appropriate crossmatch (indirect antiglobulin test) for such patient (Agrawal et al., 2016). Panel test in the case of a pregnant women coming for antenatal booking is to identify the alloantibody, determine whether the antibody can potentially cause HDFN and to allow the monitoring of the titre or quantification of the antibody every 4 weeks from booking until 28 weeks’ gestation and every 2 weeks thereafter until delivery. This information is important to determine the extent of developing foetus is affected by HDFN, decide whether to monitor the baby for anaemia using Doppler ultrasound, determine whether the baby will require intrauterine transfusion and to make an informed decision to possibly deliver the baby earlier. These evidence-based best practices are not being implemented in many settings in Nigeria (Erhabor et al., 2015). Testing of donor units for other clinically relevant red cell antigens other than ABO and Rh D is not routinely carried out (Singhal et al., 2017). This is a complete failure in stewardship by the Nigerian government and can compromise the transfusion service delivery to pregnant women and patients that require red cell transfusion. Settings and implement a policy to routinely test all group O donor units for haemolysins in other to identify group O donors with high titre of IgG anti A and/or anti B whose blood should be reserved only for transfusion to group O recipient while those that test negative can be transfused to A, B or AB individual as a way to maximizing the use of our limited allogeneic stock (Obisesan et al., 2015).

Applications of Molecular Genotyping Over Serological Phenotyping in Transfusion Medicine

Multiply-transfused Patients

The ability to determine a patient antigen profile by DNA analysis when haemagglutination tests cannot be used is a useful adjunct to a serologic investigation. Blood group genotyping in the transfusion setting is recommended for multiply transfused patients such as sickle cell disease (SCD), as part of antibody identification process (Castilho et al., 2018). Determination of a patient’s blood type by analysis of DNA is particularly useful when a patient, who is transfusion-dependent, has produced alloantibodies. This will help in the selection of antigen-negative RBCs for transfusion. It also assists in selection of compatible units for patients with discrepancies between genotype and phenotype, leading to increased cell survival and a reduction of the transfusion frequency (Bakanay et al., 2013). In addition to its contribution to the general accuracy of identification of red blood cell antigens, genotyping of transfusion dependent SCD patients allows assessment of the risk of alloimmunization against antigens

Patients Whose RBCs are Coated with IgG

Patients with autoimmune haemolytic anaemia (AIHA), whose RBCs are coated with IgG cannot be accurately typed for RBC antigens, particularly when directly agglutinating antibodies are not available, or IgG removal by chemical treatment of RBCs is insufficient. Blood group genotyping is very important for determination of the true blood group antigens of these patients (Jain et al., 2016). Patients received antigen-matched RBCs typed by blood group genotyping increases erythrocytes in vivo survival, as assessed by rises in haemoglobin levels and diminished frequency of transfusions.

Blood Donors

DNA-based typing can also be used to antigen-type blood donors both for transfusion and for antibody identification reagent panels. This is particularly useful when antibodies are not available or are weakly reactive (Huang et al., 2019). The molecular analysis of a variant gene can also assist in resolving a serologic investigation.

Resolution of Weak A, B, and D Typing Discrepancies

A proportion of blood donors and patients who historically have been typed as group O are now being recognized as group A or group B with the use of monoclonal antibodies capable of detecting small amounts of the immuno-dominant carbohydrate responsible for A or B specificity (Das et al., 2020). A typing result that differs from the historical record often results in time-consuming analyses. Since the bases of many of the weak subgroups of A and B are associated with altered transferase genes, PCR-based assays can be used to define the transferase gene and thus the ABO group (Nair et al., 2019). Similarly with the D antigen of the Rh blood group system, a proportion of blood donors that historically have been typed as D-negative are now reclassified as D-positive, due to monoclonal reagents that detect small and specific parts of the D antigen. The molecular basis of numerous D variants can be used to identify the genes encoding altered Rh D protein in these individuals (Huang et al., 2019).

Applications to Maternal-fetal Medicine

Alloimmunization against the Rh D antigen during pregnancy is the most frequent cause of haemolytic disease of the newborn (HDN). Immunization occurs when fetal cells, carrying antigens inherited from the father, enter the mother’s circulation following fetal-maternal bleeding. The mother, when not expressing the same antigen(s), may produce IgG antibodies towards the fetal antigen and these antibodies can pass through the placenta causing a diversity of symptoms, ranging from mild anaemia to death of the foetus (Erhabor et al., 2015). Apart from antibodies to the Rh D blood group antigen, other specificities within the Rh system and several other blood group antigens can give rise to HDN, but Rh D is by far the most immunogenic. Prenatal determination of fetal Rh D status is desirable in pregnancies to prevent sensitization and possible hydrops foetalis in foetuses of Rh D negative mothers with Rh D positive fathers. Fetal DNA has been detected in amniotic cells, chorionic villus samples, and as recently reported, in maternal plasma. It is now well accepted that a minute number of copies (as low as 35 copies/mL) of cell-free fetal RHD DNA in the maternal plasma can be utilized as a target for non-invasive genotyping of the foetus (Swati et al., 2018). Unlike fetal DNA isolated from the cellular fraction of maternal blood samples, free fetal DNA isolated from maternal plasma has been shown to be specific for the current foetus and is completely cleared from the mother’s circulation by postpartum. It has been reported that fetal RHD can be determined by PCR in DNA extracted from maternal plasma of pregnant women with Rh D positive foetuses, in a non-invasive procedure. PCR amplification of RHD in maternal plasma may be useful for the management of Rh D negative mothers of Rh D positive foetuses and for the study of foetus-maternal cell trafficking (Legler et al., 1999).

Conclusions

Determination of blood group polymorphism at the genomic level facilitates the resolution of clinical problems that cannot be addressed by serological technique. They are useful to determine antigen types for which currently available antibodies are weakly reactive; to type patients who have been recently transfused; to identify fetuses at risk for haemolytic disease of the newborn and to increase the reliability of repositories of antigen negative RBCs for transfusion. Mass scale genotyping, if applied to routine blood group of patients and blood donors, would significantly change the management of blood provision. Better matching of donor blood to patient would be the most significant benefit. This is primarily because a large numbers of low frequency antigens (or absence of high frequency antigen) are not routinely tested for, and donor-patient mismatches are only detected by serological cross-matching (only if an antibody has been generated) immediately prior to transfusion. This review overviews the current situation in this area and attempts to predict how blood group genotyping will evolve in the future.

Limitations

It is important to note that PCR based assays are prone to different types of errors than those observed with serological assays. For instance, contamination with amplified products may lead to false positive test results. In addition, the identification of a particular genotype does not necessarily mean that the antigen will be expressed on the RBC membrane.

Recommendation

As a word of caution, we should emphasize that the interpretation of molecular blood group genotyping results must take into account that potential contamination of PCR-based amplification assays and the observation that the presence of a particular genotype antigen does not guarantee expression of this antigen on the RBC membrane. The possibility to have an alternative to serological tests to determine the patient’s antigen profile should be considered for multiply transfused patients and for patients with autoimmune haemolytic anaemia (AIHA) by allowing the determination of the true blood group genotype and by assisting in the identification of suspected alloantibodies and in selection of antigen-negative RBCs for transfusion. This ensures a more accurate selection of compatible donor units and is likely to prevent alloimmunization and reduce the potential for haemolytic reactions. As automated procedures attain higher and faster throughput at lower cost, blood group genotyping is likely to become more widespread. We believe that the PCR technology may be used in a transfusion service in the next few years to overcome the limitations of serological technique.

References

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Climate Summit and the Egyptian Vision

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DOI: 10.31038/GEMS.2023531

“We are meeting today and the environmental clock is ticking, marking the end of the planet if we do not do our best to preserve it”.

“Although not responsible for the climate crisis, the African continent faces the most negative consequences of the phenomenon and its economic, social, security and political implications. However, the continent is a model of serious climate action as far as its capabilities and available support allow”. With these words, the British Prime Minister, Boris Johnson and His Excellency President Abdel Fattah El-Sisi began their speeches before the Climate Summit in Glasgow, Scotland, which began on Sunday, October 31, 2021 under the auspices of the United Nations – known as the twenty-sixth Conference of the Parties to the Framework Convention on Climate Change – in the Scottish city of Glasgow and will continue until November 12 within the ceiling of high expectations in dealing with the problems of climate change besetting our planet. The event is abbreviated as “26COP”, which will last for two weeks and is an acronym for the words “26th Conference of the Parties to the Framework Convention on Climate Change,” For the first time, delegations representing 200 countries participated in the summit to discuss ways to reduce emissions by 2030 and help improve life on the planet.

The summit was honored by the honorable presence of the Arab Republic of Egypt with an official delegation headed by His Excellency President Abdel Fattah El-Sisi, President of the Republic, who gave an important speech at the summit, which is attended by world leaders as evidence that we are a large country with its position at the level of the continent and the whole world. Earth’s climate depends mainly on the sun, with about 30 percent of sunlight scattered back into space, some of it absorbed by the atmosphere and the rest absorbed by the Earth’s surface. The Earth’s surface also reflects part of the sunlight in the form of animated energy called infrared radiation. What is happening is that infrared radiation is delayed by “greenhouse gases” such as water vapor, carbon dioxide, ozone and methane, which cause infrared radiation to bounce back, raising the temperature of the lower atmosphere and the Earth’s surface.

Although greenhouse gases make up only one percent of the atmosphere, they form a blanket around the ground or a glass roof, which traps heat and keeps the Earth’s temperature at 30 degrees higher than otherwise. However, human activities contribute to making this cover “thicker” because natural levels of these gases are supported by carbon dioxide emissions from the combustion of coal, oil and natural gas, through the emission of more methane and nitrous oxide produced from agricultural activities and landuse changes, and through long-lived industrial gases that are not produced naturally. People usually use the terms global warming and climate change interchange, assuming they say the same thing. But there is a difference between the two: global warming refers to rising average temperatures near the Earth’s surface, while climate change refers to changes in atmospheric layers such as temperature, rainfall and other changes measured over decades or longer periods.

What is Climate Change?

Climate change refers to long-term shifts in temperature and weather patterns. These shifts may be natural – for example, through changes in the density of the Sun, slow changes in the Earth’s rotation around the Sun, or natural processes within the climate system (such as changes in the water cycle in the oceans), but since the nineteenth century, human activities have become the main cause of climate change on the planet. This is mainly due to the burning of fossil fuels, such as coal, oil and gas as a result of various industries and human activities such as the use of fuel in cars, deforestation, reforestation, urbanization, desertification, etc., where the burning of fossil fuels produces the emission of gases that act as a cover that wraps around the globe, especially carbon nan gas and methane, which leads to the capture of the sun’s heat and raising the earth’s temperatures. This releases carbon dioxide and landfills are a major source of methane emissions. Energy production and consumption, industry, transport, buildings, agriculture and land use are the main sources of emissions. Recent studies have shown that concentrations of these gases are now at their highest levels in two million years. Emissions continue to rise as a result of their continued sources. As a result, the globe is now 1.1 degrees Celsius warmer than it was in the late nineteenth century.

What are the Expected Effects of Climate Change?

The phenomenon of climate change is distinguished from most other environmental problems in nature by being global in nature, as it transcends the borders of countries to pose a danger to the whole world. The steady increase in surface air temperatures on the globe as a whole has been confirmed, with the global average increasing at a rate of 0.3 to 0.6 degrees over the past 100 years. Studies by the Intergovernmental Panel on Climate Change (IPCC) have indicated that the continuous rise in the global average temperature will lead to many serious problems such as sea level rise threatening to submerge some areas in the world, as well as the impact on water resources and crop production, in addition to the spread of some diseases. Climate change is sure to affect our health and our ability to farm, live, safety and work as the consequences of climate change include severe drought, water scarcity, severe fires, rising sea levels, saltwater infiltration of adjacent lands, floods, melting polar ice and degradation of biodiversity. In a 2018 United Nations report, scientists acknowledged that limiting global warming to no more than 1.5°C would help us avoid the worst climate impacts and maintain a livable climate. Conversely, the current trajectory of carbon dioxide emissions could increase global temperatures by up to 4.4°C by the end of the century.

Everyone Asks: Can We Stop the Phenomenon of Climate Change?

The honest scientific answer: It is only possible to slow the pace of global warming, not stop it completely, thus delaying the scale of the damage and reducing it until the end of the current century in the hope that we can coexist as a human race with the variables that we have caused. Climate change poses a great challenge to humanity, so do we have solutions to this phenomenon? The countries of the world have become aware of the danger of silence on the phenomenon of climate change and the need to confront it effectively, as the effects of climate change have existed for a while, but some countries of the world were not dealing with this crisis effectively and adequately, especially the industrialized countries that cause climate change and are negligent in the right of developing countries, where they do not take measures that protect the world from climate change and do not provide adequate funding. Despite this, there are some measures that can be taken to reduce this phenomenon and its catastrophic effects, the most important of which are:

Emission Reduction

This can be done by shifting existing energy systems from fossil fuels to new and renewable energy sources, such as solar or wind, thereby reducing climate-changing emissions. Here, a growing coalition of countries is committed to bringing emissions to net zero by 2050. However, current emissions must be cut by about half by 2030 to keep global warming below 1.5°C, and fossil fuel production must be reduced by about 6 percent per year during the decade 2020-2030.

Adaptation to Climate Impacts

Humanity must also adapt to the potential future consequences of climate change. Priority must be given to the most vulnerable people with the least resources to face climate risks, especially in developing countries that are least involved in and most affected by the phenomenon.

Financing the required amendments and procedures. Climate adaptation and coping with its effects require significant financial investments, but inaction on climate action comes at a high price. An important step is the fulfillment by industrialized countries and the main cause of the phenomenon of their commitment to provide financial allocations to developing countries so that they can adjust and move towards greener economies.

Is July 2021 really the hottest month in recorded history?

One of the parties says that July 2021 is the hottest month in the history recorded on the surface of the earth.

What is the Truth of That?

This was shown in a report by one of the US federal agencies concerned with monitoring the atmosphere and oceans in August 2021, where it announced that July 2021 was the hottest month in history since the start of the world’s temperature recording system on the planet 142 years ago. The recorded data reveal that the average temperature during this month over the earth, and the oceans together, increased by about 0.93 degrees Celsius, from the average temperature in the twentieth century, which is 15.8 degrees Celsius, and scientists believe that this is due to the long-term effects of the phenomenon of climate change. Has the number of days of extreme heat really doubled globally since the eighties of the last century?

Research conducted by the BBC found that the number of very hot days in which temperatures exceed 50°C, which are witnessed in different parts of the world annually, has doubled since the eighties of the last century. The total number of days when temperatures exceeded 50°C has increased in each of the past four decades. Between 1980 and 2009, temperatures exceeded 50°C for just 14 days, while the number rose to 26 days between 2010 and 2019. This has happened in increasing areas of our globe, which presents humanity with new challenges, especially in terms of health and livelihood aspects in general.

What are the Groups Most Affected by the Phenomenon of Climate Change?

Although all groups are affected by the results of the phenomenon of negative climate change, children bear the brunt of its effects, although they are the least responsible group for the occurrence of the phenomenon, as climate change poses a direct threat to the child’s ability to survive, develop and prosper.

In terms of:

The severity of weather phenomena such as hurricanes and heat waves threaten children’s lives and destroy infrastructure vital to their well-being.
Floods cause the destruction and damage of water and sanitation facilities, leading to the spread of various diseases,
which represent an imminent danger to humans in general and children in particular.
Drought and global change in rainfall lead to disruption in crop productivity and increased food prices, which means food insecurity and food deprivation for poor people, including of course children.

Children are the most vulnerable group to diseases that will become more prevalent as a result of climate change and drought, such as malaria, fever and pneumonia, which alone kills 2,400 children a day globally and is closely linked to under nutrition, lack of safe drinking water and air pollution, symptoms exacerbated by climate change.

The frightening and terrifying effects of climate change: In a report broadcast by the agency “AFP”, on the impact of climate change on humanity, it is clear that: Some 166 million people in Africa and Central America needed assistance between 2015 and 2019 due to food emergencies linked to climate change. Between 15 and 75 million people are at risk of famine by 2050. Some 1.4 million children will be severely stunted in Africa due to climate change in 2050. Agricultural yields have declined by 4-10% globally over the past 30 years.

Catches in the tropics have declined by 40-70%, with rising emissions.

As for the impact of climate change on internal migration, between 2020 and 2050, the rate will increase to 6 times the current rate.
Global warming will also have terrifying effects on “water stress”, with 122 million people in Central America, 28 million in Brazil, and 31 million in the rest of South America affected by a shortage of water allocations.

Climate change in Egypt and its negative effects Egypt is one of the countries most affected by the negative effects of climate change, and these effects are summarized as follows:

Impact on food security
Impact on water resources
Impact on the ecosystem
Impact on public health
Impact on urban areas
Impact on energy
Impact on the economy

What about the Egyptian Strategy to Confront Climate Change?

The phenomenon of climate change is distinguished from most other environmental problems as it is global in nature, as it transcends the borders of countries to pose a danger to the whole world, as President Abdel Fattah El-Sisi participated in the Climate Change Summit under the auspices of the United Nations – known as the Twenty-sixth Conference of the Parties to the Framework Convention on Climate Change – in the Scottish city of Glasgow, which began on Sunday, October 31 and continued until November 12. During the closing session of the Glasgow Conference “COP 26”, it was announced that Egypt was chosen to host the 27th session of the COP27 conference on November 7 and 8 in Sharm El Sheikh, making Egypt the first country at the level of Africa to host the next climate summit, so the entire black continent will be represented in the conference, and therefore the whole world will see the efforts of Egypt and the African continent in confronting climate change.

The Egyptian strategy to confront climate change is represented in many points, the most important of which are:

Establishing the National Council for Climate Change to formulate the state’s general policies regarding dealing with climate change, and work to develop and update sectoral strategies and plans for climate change, in light of international agreements and national interests, and link these plans to the sustainable development strategy 2030.
Egypt protects its coasts on the White and Red Sea from the impact of sea level rise through clear plans carried out in cooperation between ministries and concerned scientific authorities.
Research bodies in Egypt are working to develop drought resistant agricultural crops and crops that reduce emissions.
Egypt is working to protect the agricultural area adjacent to the beaches from deterioration through mega projects.
Provide climate finance for the implementation of the adaptation component of the NDCs.
Egypt is implementing a huge desalination program (Ain Sokhna desalination plant at a cost of 2.3 billion pounds) and tertiary treatment of wastewater (Bahr Al-Baqar water treatment plant at a cost of 20 billion pounds) and Egypt is updating its strategy for low-emission development and implementing a huge renewable energy program (wind power generation project on the west coast of the Gulf of Suez at a cost of 4.3 billion pounds,)
Implementation of huge projects in the villages of the Egyptian countryside, such as the Decent Life project at a cost of 700 billion pounds.
Implementation of projects to preserve available water resources, such as the project of lining canals at a cost of 6 billion pounds. Egypt is the first country in the region to issue $750 million worth of green bonds last year.
Expansion of projects to establish greenhouses with the aim of adapting to climate change (the target during the next five years is about one million greenhouses.)
Expanding sustainable transport projects, developing the transport and communications network (at a total cost of 377 billion pounds until 2024), converting cars to work with electricity or natural gas, and operating trains with electricity to eliminate pollution.
Expanding health initiatives to maintain the health of citizens from various diseases.
Production of new varieties and hybrids of rice, such as short-lived varieties, which reduces methane emissions.

Facile Synthesis Process, Characterization Study and Determination of Thermoluminescence Kinetic Parameters of Combustion-Synthesized Nano Phosphor for Dosimetry and Long Persistent Applications

4 Replies

DOI: 10.31038/NAMS.2023634

Abstract

In this section, we describe the facile urea-assisted combustion synthesis technique that was used to synthesis of the Dy³⁺activated Ca₂MgSi₂O₇ phosphor at the already maintained muffle furnace temperature 600°C. In addition, the characterization studies of the synthesized powder samples are well reported on the basis of their structural, morphological, elemental, and thermal analysis. The synthesized Ca₂MgSi₂O₇:Dy³⁺ nanophosphor was further characterized by using XRD, FESEM, EDX, and, TL analysis. The obtained XRD pattern indicates tetragonal crystal structures that are compatible with JCPDS card number #79-2425 and recognizes the formation of the desired Ca₂MgSi₂O₇ host without any traces of impurity for confirmation of phase purity. The average crystallite size was estimated using Debye-Scherer’s formula, and was found to be in the range of ~27 nm. It performed a FESEM study to demonstrate exterior morphology. EDX spectra have been employed to establish the sintered phosphor’s elemental composition. The acquired TL glow curve have used to determine the thermal characteristics of the as-synthesized phosphor. Dy³⁺ doped samples have exposed for 15 min to UV exposure show optimum TL intensity at 112.21°C. With alterations to UV exposure time, it also becomes apparent that the ambient temperature corresponding to the TL peak remains constant. In order to conduct further research on characteristics including activation energy, order of kinetics, and frequency factor, samples with 4 mol% of Dy³⁺ exposed for varied UV exposure times were chosen. All of these parameters were assessed using the peak shape method. The aforementioned results suggest that an alternative preference for thermoluminescence dosimetry (TLD) and long-lasting applications is the combustion-synthesized Dy³⁺-doped Ca₂MgSi₂O₇ nanophosphor.

Keywords

Combustion, XRD, FESEM, EDX, Tetragonal, Thermoluminescence (TL), Ca₂MgSi₂O₇:Dy³⁺

Introduction

Researchers and material scientists have lately been paying special attention to compounds of nanosized luminescent materials of the melilite group doped with rare earth (RE) ions. Alkaline earth silicate phosphors have excellent qualities like high quantum efficiency, abundance, resistance to weathering, affordability, and environmental features. Silicates were also thought to be one of the best host materials for luminescence centers due to their chemical and thermal stability and long persistence times [1]. The reduction of particle size can result in remarkable modifications of some of their bulk properties, nanosized phosphors usually exhibit novel capabilities, such as higher luminescent efficiency [2], and remarkable application potential. The melilites are a large group of compounds characterized by the general formula , where M is a large monovalent or divalent cation, T¹ is a small divalent or trivalent cation in tetrahedral, T² is also a small cation in the other tetrahedral and X is an anion. Afterglow in melilite has already been well documented [3]. In the field of luminescence, the potential utility of lanthanide ions as activators has recently become widely recognized [4]. The afterglow properties of phosphors can be tailored to last for a few seconds to several hours using various activators [5]. Dy³⁺ is a very effective luminescent centre when utilized as an activator, according to several experimental results of luminescence in some inorganic systems. Furthermore, Dy³⁺ doped Ca₂MgSi₂O₇phosphor has been extensively explored for its thermoluminescence properties as a long-lasting phosphor. The persistent emission appears stronger when Dy³⁺ is added to the host because it is very likely that these ions are involved in electron trapping. With regard to the ability of two Dy³⁺ ions to substitute for the three ions of the host, it’s possible that the Dy³⁺ ions will play a role in the creation of defects that act as oxygen vacancies or electron traps [6,7]. Properties like linearity, dose range, energy response, repeatability, stability of stored information, and isotropy are taken into consideration while evaluating the performance of TLD [8]. The preparation of TLDs had good chemical and moisture stability as a result of the addition of SiO₂.xH₂O and the prudent choice of the chemical form of activators. To analyze the trap centers and trap level in an insulator or semiconductor driven by any radiation-source, TL is one of the most effective techniques [9]. Traps produced by the lattice imperfections play a significant role in the TL characteristics of the phosphors [10].

Accordingly, traps play an essential role in TL research. Understanding the composition of charge carriers’ trapping states is also important. The trapped electrons release energy when heated because they move back to their normal, lower-energy positions. By comprehensively analyzing the TL glow curve, one can learn regarding the trap states and recombination centers [11]. Nowadays, TL materials are widely studied as an effective tool for various applications in the fields of material characterization, archaeological and geological dating, radiation dosimetry, biological applications, age determination, geology or solid-state defect structure analysis, personnel and environmental monitoring etc., being done. Therefore, we suggest that the sintered Dy³⁺ doped Ca₂MgSi₂O₇ phosphor is a preferable long-persistent phosphor and novel TL material because rare earth dysprosium [Dy³⁺] ions mainly act as trap centers. In our present investigation, the TL intensity is highly dependent on the concentration of dopants (Dy³⁺) ions. The maximum intensity of Dy³⁺ ions was 4 mol% and TL intensity optimum for 15 min UV exposure radiation time and then TL intensity decreases with further UV exposure.

In this article, we have described the synthesis-characterization and thermoluminescence characteristics of prepared the calcium magnesium silicate phosphor (Ca₂MgSi₂O₇:Dy³⁺) by combustion synthesis utilizing urea (NH₂CONH₂) as fuel and boric acid (H₃BO₃) used as flux. Equipped phosphors were characterized and investigated by using X-ray diffractometer (XRD), field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDX) analysis and Thermoluminescence (TL) analysis in order to structural, morphological, elemental composition, and thermal properties of synthesized powder samples. The aim of this paper is to present the kinetic parameters of the main glow peak (385.21 K) of Ca₂MgSi₂O₇:Dy³⁺, which have important aspects in the general description of physical characteristics of TL materials, using peak shape (PS) method, namely the order of kinetics (b), symmetry factor (µ_g), activation energy E (in eV), the frequency factor S (in s⁻¹).

Experimental Analysis

Combustion Synthesis

In order to meet the demands of Material Science and Engineering to create inorganic materials with the appropriate composition, structure, and property, combustion synthesis (CS) has been developed as a standard approach. To sustain a self-propagating high reaction temperature, CS employs extremely exothermic (∆H ≤ 170 kJ/mol) redox (reduction-oxidation) chemicals and combinations, as well as explosive reactions. Metal nitrates serve as the oxidant while urea serves as the fuel in the combustion process. Additionally, this method has the ability to enhance materials, save energy, and protect the environment [12]. The combustion process’ key benefits include rapid heating rates, better processing times, energy efficiency, and the capacity to yield superfine, homogenous, nanocrystalline powders from the combustion products. A vital component of the simple method without a requirement for an expensive high-temperature furnace is the implementation of the enthalpy of combustion to produce and crystallize powders at low calcination temperatures [13]. This technology can effectively replace time-consuming traditional solid-state reaction and sol-gel processing techniques [14]. Numerous refractory materials, such as borides, nitrides, oxides, silicides, intermetallic, and ceramics, have been prepared using this technique.

Powder Sample Preparation

Combustion technique (Figure 1) was successfully employed for the preparation of M₂MgSi₂O₇: Dy³⁺ (M=Ca) nanophosphor. The starting materials used for the preparation were of Analar grade with high- purity (i.e. 99.99%) and include calcium nitrate [Ca (NO₃)₂.6H₂O], magnesium nitrate [Mg (NO₃)₂.6H₂O], dysprosium nitrate [Dy (NO₃)₃.5H₂O], and fumed silica (SiO₂.xH₂O). All metal nitrates were considered as sources of oxidizers, boric acid [H₃BO₃] as flux, and urea [NH₂-CO-NH₂] was used as fuel. The stoichiometric quantities of the mixture were stirred thoroughly using a magnetic stirrer to obtain a clear solution. The resulting solution was placed in a preheated muffle furnace maintained at 600°C for 5 min. Initially, the solution was thermally dehydrated and later ignited with the liberation of large amount of gases (N₂, O₂, etc.). Once ignited, the combustion propagates on its own without the need of any external heat. The silicate in a foamy form was obtained finally.

Figure 1: Synthesization of Ca₂MgSi₂O₇: Dy³⁺ nanometer powder using combustion synthesis technique

After the completion of the process, the product was grinded well using agate mortar pastel to convert into a fine powder form. Further, the sample was post-annealed at 900°C for 2 h under an air atmosphere. In order to obtain white powder, the sample was then despondent cooled to room temperature. The resulting sample was put back together in an airtight bottle for additional characterization investigations such XRD, FESEM, EDX, and TL analysis. Assuming total combustion of the redox mixture for the synthesis of Ca₂MgSi₂O₇ could be written as:

Ca (NO₃)₂.6H₂O + Mg (NO₃)₂.6H₂O + SiO₂.xH₂O + NH₂CONH₂+ H₃BO₃→ Ca₂MgSi₂O₇+ H₂O (↑) + CO₂ (↑) + N₂ (↑) (1)

Ca (NO₃)₂.6H₂O + Mg (NO₃)₂.6H₂O + SiO₂.xH₂O + Dy (NO₃)₃.5H₂O + NH₂CONH₂+ H₃BO₃→ Ca₂ MgSi₂O₇: Dy³⁺ + H₂O (↑) + CO₂ (↑) + N₂ (↑) (2)

Powder Sample Characterization

Phase structure and composition of the synthesized samples remained categorized by X-ray diffraction arrangement using Bruker D8 advance X-ray diffractometer with Cu-K_α radiation having wavelength 1.5405 Å at 40 kV, and 40 mA. The XRD data were measured over a scattering angle range of 10° to 80°. The surface morphology and EDX analysis performed with the help of FESEM (ZEISS EVO Series EVO 18 microscope) fitted with EDX spectra. Thermoluminescence (TL) glow curves of the UV-irradiated (254 nm) samples were plotted between emitted TL intensity and the corresponding temperature using routine TL set-up Nucleonix TLD reader (1009I) with constant heating rate 5°Cs^-1.

Fuel and Oxidizers

Fuel and oxidizers must be utilized during the combustion synthesis process. All metal nitrates are employed as oxidizers, together with boric acid (H₃BO₃) as a flux and urea (NH₂CONH₂) as a fuel for combustion. The stoichiometric proportions of all metal nitrates and fuel are calculated using the propellant’s chemistry. With the calculation of oxidizer to fuel ratio, the elements were assigned formal valences as follows: Ca=+2, Mg=+2, Dy=+3, Si=+4, B=+3, C=+4, H=+1, O=-2, and N=0 [15].

Oxidizer and Fuel Ratio

Determining the oxidant to fuel ratio is the most important phase since it is the deciding factor that affects the characteristics of the nanomaterials that will be created. The oxidizer to fuel ratio is termed as “Ψ”, which is defined as following relation [16].

This ratio is very crucial in determining parameters such as reaction temperature and numerous characteristics of nanosized materials such as electrochemical, crystallinity, phase purity and morphology. Additionally, it has been also observed that the particle size of nanomaterial is influenced by the oxidant-fuel ratio. Hence, the oxygen/fuel ratio at which the heat generated by combustion is maximum is 1 [17].

Effect of Fluxes

Some unique fluxes, including Li₂CO₃ (lithium carbonate), NH₄F (ammonium fluoride), NH₄Cl (ammonium chloride), BaF₂ (barium fluoride), YF₃ (Yttrium Fluoride), AlF₃ (aluminum fluoride), H₃BO₃ (boric acid) [18], KCl (potassium chloride), LiF (lithium fluoride), CaCl₂ (calcium chloride) [19] etc. are additionally included with the initial precursors to enhance the creation of crystal structures and the properties of the materials, speed up the reaction, and decrease the reaction temperature. The morphological properties of silicate materials are influenced by flux, which additionally enhances the luminous efficiency of powders. The potential benefits and rate of the reaction are influenced by the reactants’ structural characteristics and the reaction circumstances. Any nano- and micro-phosphors’ crystal structure development depends significantly on fluxes. Any formation moves along more quickly because to these fluxes. The final outcome is the synthesis of phosphors with actual chemical structures [20].

Results and Discussion

Powder X-Ray Diffraction Analysis (XRD)

An efficient, necessary, analytical, and nondestructive method for material characterization is powder X-ray diffraction analysis [21]. Diffraction is an X-ray-based technique that provides information on a unit cell’s chemical composition, phase structure, and crystallinity, as well as its microstructure, crystallinity, and stress analysis. It also provides data on its percentage phase composition, inter-planar spacing, and lattice parameters. Figure 1 shows the crystal phase of the phosphor. Comparison of the recorded XRD patterns with the standard JCPDS card number #79-2425 showed good agreement [22]. Akermanite-type structure describes the crystalline structures of synthesized phosphor, which is a member of the tetragonal crystal system with the cell parameters a=b=7.8071 Å, c=4.9821 Å; and α=90°, β=90°, γ=90°, as well as space group is P¯42₁m (113 space number and D³_2d space group) and point group is -42 m. Ca₂MgSi₂O₇ crystal structure has a cell volume of 303.663 Å³ and a molar density of 2.944 gm/cm³ [7,23]. The XRD pattern (Figure 2) shows that the sample is single phased, which is consistent with JCPDS file no. 79-2425.

Figure 2: XRD patterns of host & Dy³⁺activated Ca₂MgSi₂O₇phosphor

Estimation of Crystallite Size (D)

The XRD measurement displays a slight shift towards the larger angle in contrast to the standard reference data. From the XRD diffraction peaks, the crystallite size was determined with the help of the Debye-Scherrer empirical formula [24,25].

Debye-Scherrer numerical expression as follows:

where k is the Scherrer constant, D is the crystallite size for the (hkl) plane, 𝜆 is the wavelength of the incident X-ray radiation [Cu-K_α (1.5405 Å)], β is the full width at half maximum (FWHM) in radiations, and 𝜃 is the corresponding angle of Bragg diffraction. Based on the Debye-Scherrer’s formula, the average particle size obtained from the XRD measurement is ~27 nm, which displays in nano form.

Analysis of Surface Morphology (FESEM) Micrographs

The combustion-synthesized phosphor’s morphology at a 2-micron scale can be seen in the FESEM micrograph (Figure 3), which suggests that the synthesized crystal is in nano form. The particles’ highly agglomerated crystallite shape gives them a frothy appearance. The precursor particles had a spherical shape and were microscopic in size. It also shows aggregated grains, which might be a result of the powder’s extended stay within a combustion furnace. Throughout the combustion reaction process, the particles cluster and get larger. In present case, we have determined the mean value of particle size by Image J software about 20.492 nm.

Figure 3: FESEM morphological Image of Dy³⁺activated Ca₂MgSi₂O₇Phosphor with 20.00 K X magnification

Despite the fact that a sample containing stoichiometric proportions of redox mixture boils, goes through dehydration, and then decomposes, creating combustible gases which involves oxides of N₂, H₂O, and nascent oxygen when heated fast to 600°C. The doped phosphor lattice is able to develop in the ideal environment, which forms when the volatile combustible gases ignite, burn with a flame, and ignite. In addition, this procedure makes it possible to uniformly (homogeneously) dope rare-earth impurity ions in one step. We also anticipate that the particle surface shape may have an impact on the thermal characteristics of these phosphor materials.

Figure 4 shows the electron Image of the synthesized Ca₂MgSi₂O₇: Dy³⁺ phosphor. It is clearly evident from the picture that the dysprosium ions are well deep trapped in the host crystal lattice sites. That is, they are indicating deeper traps. Dy³⁺ ions served as hole traps (Dy³⁺ + hole → Dy⁴⁺). Between the lower energy state (ground) and higher energy state (excited) state, Dy³⁺ ions serve as deep hole trap levels. Dy³⁺ ions may trap holes or electrons or just to create/modify defects as a result of charge compensation. The deeper traps are highly responsible for the persistent luminescence.

Figure 4: Electron image of synthesized Ca₂MgSi₂O₇: Dy³⁺ phosphor

Analysis of Energy Dispersive X-ray (EDX) Spectroscopy

Using EDX spectra, the chemical constituents of the powder sample has been determined. Identification and measurement of the elemental composition of sample areas as small as a few nanometers are conventional procedures [26]. In EDX spectra, the presence of Ca, Mg, Si, O and Dy intense peak are present which preliminary indicates the formation of Ca₂MgSi₂O₇: Dy³⁺ phosphor in Figure 5.

Figure 5: EDX Spectrum of Dy³⁺ activated Ca₂MgSi₂O₇ phosphor

As well as the existence of dysprosium is clear in their corresponding EDX spectra. Their appeared no other emission apart from calcium (Ca), magnesium (Mg), silicon (Si), oxygen (O), and dysprosium (Dy) in Ca₂MgSi₂O₇: Dy³⁺ EDX spectra of the phosphor. The elements present in the Weight% and Atomic% also determined which is represented in Table 1.

Table 1: Chemical composition of synthesized Ca₂MgSi₂O₇: Dy³⁺ phosphor

Sr.	Element	Weight%	Atomic%
1.	O K	54.98	71.64
2.	Mg K	6.57	5.63
3.	Si K	13.98	10.38
4.	Ca K	23.50	12.22
5.	Dy L	0.97	0.12
6.	Totals	100.00	100.00

Thermoluminescence (TL) Analysis

TL Spectra

When some of the energy needed to irradiate a material is used to move electrons to traps, a phenomenon referred to as thermoluminescence (TL). This energy, which was trapped as trapped electrons, is released when the material’s temperature rises, turning the luminescence that results into TL emission [27]. The thermo luminescence dosimetry (TLD) of ionizing radiation, thermo luminescence dosimetry (TLD) for dating applications, and also provides insights on the trap levels are all extensively employed features of the TL technique [28]. The basic goal of TL experiments is to acquire data from an experimental glow curve, or from a series of experimental glow curves, and to analyze that data in order to determine values for all of the parameters with regard to the relevant luminescence mechanisms.The single and strong TL glow curve of UV-irradiated Dy³⁺ (4 mol%) activated Ca₂MgSi₂O₇with constant heating rate (5°C/sec) at different UV radiation times (i.e. 5 min, 10 min, 15 min, 25 min, 25 min) is shown in Figure 6. Since the population of trapped electrons in a metastable state reaches a maximum value at a specific time, the TL intensity in this case increases with increasing irradiation time up to 15 min, then decreases with time. From the TL glow curve of Ca₂MgSi₂O₇:Dy³⁺ it was observed that single broad fitted peak are centered at 112.21°C. The corresponding depth of the trap at 112.21°C should be deeper (high temperature). Deeper traps are highly helpful for increasing the long persistent duration and afterglow process [7]. Therefore, TL data reveal the presence of single trapping levels in Ca₂MgSi₂O₇:Dy³⁺phosphor.

Figure 6: TL glow curve of synthesized Ca₂MgSi₂O₇:Dy³⁺ phosphor

Concentration Effect of Dy³⁺ ions

It is obvious that the TL intensity rises with rising Dy³⁺ concentration, reaches a maximum value at 4 mol%, and then falls with increasing Dy³⁺ ion concentration. The distance between the activators ions decreases as the activator concentration rises. The ions get involved more frequently, and energy is transferred. On the other hand, the energy that the ions store decreases as the activator concentration rises [7,26]. Consequently, there is an optimum concentration of the activator ions. As is seen from figure the favorable concentration of Dy³⁺ in Ca₂MgSi₂O₇ nanophosphor is about 4 mole % (relative to Ca²⁺). The ionic radii of Ca²⁺, Mg²⁺, Si⁴⁺ and Dy³⁺ are 1.12 Å, 0.58 Å, 0.26 Å, and 0.97 Å, respectively [29]. When Dy³⁺ ions doped into Ca₂MgSi₂O₇ host lattice, they may prefer to occupy the Ca²⁺ crystallographic site rather than Dy³⁺ site, because the radius of the Dy³⁺ is very closer to that of the Ca²⁺ lattice site [30]. A positive centre (hole) is formed when a trivalent metallic ion (such as Dy³⁺) substitutes a divalent metallic ion in a host lattice. So, Dy³⁺ ions hardly incorporate into tetrahedral [MgO₄] and [SiO₄] and only incorporate into [CaO₈] anions complexes in host lattice [31]. The traps are released when the phosphor is heated, and the intensity of the thermoluminescence is raised by radiative recombination at the Dy³⁺ ions.

Peak Shape Method

The most significant glow curve peak’s kinetic parameters are found using the peak shape approach (Figure 7), also referred to as Chen’s empirical method [32]. The kinetic/trapping parameters such as the trap depth or activation energy (E), the order of the kinetics (b), and the frequency factor (s) have a significant impact on the TL characteristics. The area under the curve, the heating rate, the form of the glow curve, and other analytical techniques have all been developed to get TL parameters. The next sections provide a brief overview of the peak shape approach and the findings it produced for the current investigation.

Figure 7: An illustration of a typical thermoluminescent light curve utilizing the peak shape approach

Calculation of Kinetic/Trapping Parameters

[a] Order of kinetics (b)

Recombination of de-trapped charge carriers with their counterparts is referred to as the order of kinetics (b), and the order of kinetics depends on the TL peak shape approach. The TL glow peak of the Ca₂MgSi₂O₇:Dy³⁺phosphor TL glow curves was calculated using Chen’s empirical formula.

The geometrical factor μ_g was calculated as:

Here, T_m is the temperature corresponding of high peak intensity, whereas T₁ and T₂ is the ascending and descending part of peak correspond to the full-width at half maxima (FWHM). The TL glow peak divided between first and second order of kinetics of geometric factor defined, first order kinetics (μ_g)=0.39-0.42, (μ_g)=0.49-0.52 is the second order kinetics and (μ_g)=0.43-0.48 is the mixed order of kinetics [33].

The calculated symmetry factor (g) for the single peak was 0.47-0.51, which is close to the value for the second-order kinetics. This demonstrates that the single band’s peaks are of second order. The outcome shows that, in compared to the first-order example, the chance of retrapping carriers is higher after the carriers from the traps corresponding to the single bands were freed [34].

[b] Activation energy (E)

We used the following equation to estimate the depth of the traps, (E). It is calculated by the general formula, which is valid for any kinetics. It is given by,

For general order kinetics c_α and b_α (α=τ, δ, ω) are calculated by following expression,

[c] Frequency factor (S)

After being exposed to ionizing radiation, the frequency factor is a probability that indicates the escape of electrons from the traps. After determining the kinetics order (b) and activation energy (E), the frequency factor (s) has been determined from the following equation and the values of b and E were substituted.

Here, β is heating rate, k is Boltzmann constant, and b is the order of the kinetics, which is 2 in this case. The TL glow curves were recorded by TLD reader (Nucleonix Model 1009I)) with a linear heating rate of 5°C s⁻¹ [35].

Table 2 shows the effects of various UV exposure times, such as 5, 10, 15, 20, and 25 minutes, on the Ca₂MgSi₂O₇:Dy³⁺phosphor and several TL kinetic parameters, such as trap energy, symmetry factor, and frequency factor.

Table 2: Values of different Kinetic parameters of the main TL glow peak curves of Ca₂MgSi₂O₇:Dy³⁺phosphor calculated from using peak shape method.

UV Radiation Time	(^oC)	(^oC)	(^oC)					E (eV)	Frequency Factor
5 min	86.43	112.21	139.36	25.78	27.15	52.93	0.51	0.72	1.2 × 10⁷
10 min	87.33	112.21	136.10	24.88	23.89	48.77	0.49	0.77	2.87 × 10⁷
15 min	87.33	112.21	136.10	24.88	23.89	48.77	0.49	0.77	2.87 × 10⁷
20 min	85.69	112.21	139.36	26.52	27.15	53.67	0.51	0.71	1.2 × 10⁷
25 min	85.69	112.21	136.10	26.52	23.89	50.41	0.47	0.66	1.1 × 10⁷

This method was applied to the cleaned main peak determined by means of trap energy (E), frequency factor (s) and symmetry factor (μ_g) were calculated using Eqs. (5) and (6). Symmetry factor (μ_g), average trap energy and frequency factor were found between in the range of 0.47-0.51, 0.66-0.77 eV and 1.1 × 10⁷ to 2.87 × 10⁷ s⁻¹, respectively. Thus, in our case, we obtained the maximum thermo-luminescence [TL] in 15 min UV exposures time. In our case, symmetry factor (μ_g) is lies between 0.47-0.51, which signs that it is a case of second order kinetics, responsible for deeper trap depth. According to Sakai’s and Mashangva report, he is also reported that a trap depth between 0.65-0.75 eV is very appropriate for long afterglow properties [36,37].

It is obvious that the dysprosium ion, because of its inherent nature, is more to responsible for the hole trap level. That is, the dysprosium ion’s inherent properties enable it to produce a hole trap level as soon as it reaches the host crystal lattice. In a host lattice site, these hole trap levels are trapped extremely deeply. The material has long-lasting properties as a result of these deeper traps.

Conclusion

Tetragonal samples of Ca₂MgSi₂O₇ with 4 mol% dopant concentration of Dy³⁺ ions have been successfully synthesized by combustion synthesis technique method at 600°C, which appears to be the most feasible method for their production. For better understanding its spectroscopic and luminescent characteristics, several characterization approaches were investigated. Amorphous structure and nanoscale particle size were determined using XRD and FESEM analyses. The crystallite particle size has been calculated as 27 nm and 20.492 nm. The size of the crystallites has been achieved in the nano order and nano range with considerably greater uniformity. The surface morphology of the particles is shown by the FESEM data to have a flake-like structure, a uniform, homogenous, superfine crystal structure, and to have aggregated firmly. The EDX spectra confirmed the presence of Ca, Mg, Si, O and Dy elements in Ca₂MgSi₂O₇:Dy³⁺ phosphor. The TL glow curves are centered at 112.21°C for 15 min UV exposure time, which displays optimum UV exposure time. TL study shows that the optimum Dy³⁺ concentration was found for 4 mol%. The probability of recapturing released charge carriers before recombination is supported by the second order kinetics. The long after glow process is being enhanced considerably by Dy³⁺ ions. The activation energy of Ca₂MgSi₂O₇:Dy³⁺ was found to be 0.66-0.77 eV. On the basis of the value of the activation energy, we have suggested that the Combustion-synthesized Ca₂MgSi₂O₇:Eu²⁺, Dy³⁺ phosphor is an excellent thermoluminescent material and a more efficient long persistent material. It may highly applicable for TL dosimetry and long persistent applications.

Future Scope of This Work

The advancement of energy-efficient transmission, storage, and generating technologies using nanomaterials has significantly enhanced the effectiveness of both conventional and renewable energy sources. The thermoluminescence properties of nanomaterials have highly applicable in archeological dating, forensic science, geology, medical dosimetry, environmental radiation, oncology radiation, biological science, radiation physics, medicine, neutron-dosimetry, UV radiation monitoring, high-level photon dosimetry radiation. Radiation therapy or radio-therapy have used in a cancer disease treatment and kill cancer cells. As-synthesized Ca₂MgSi₂O₇: Dy³⁺ phosphor is an excellent thermoluminescent material and a more efficient long persistent material.

It is highly applicable in TL radiation dosimetry applications for personnel and environmental monitoring. The luminescent features of biomaterials have prospective applications in different areas such as DNA transplantation of tumor in the field of biological science, signal processing or image recognition in the field of computer science and information technology, drug delivery in the field of pharmaceutical science, and in the field of nutrition therapy, chemotherapy, as well as in the field of tissue engineering and bone-tissue engineering.

Acknowledgement

We gratefully acknowledge the kind support for the facility of XRD, FESEM, and EDX analysis Dept. of Metallurgical Engineering, NIT Raipur (C.G.). Authors are also thankful to Dept of physics, Pt. Ravishankar Shukla University, Raipur (C.G.) for providing us the facility of thermoluminescence (TL) analysis. We are also heartily grateful to Dept. of physics, Dr. Radha Bai, Govt. Navin Girls College Mathpara Raipur (C.G.), providing the facility of muffle furnace and other essential research instruments

Competing Interests

Authors have declared that no competing interests exist in this present research investigation.

Authors Contribution

Both authors contributed to the completion of this work. Author Dr. Shashank Sharma undertakes the manuscript designed and conducted the entire experiments and characterization studies, collected and analyzed the research data, and prepared the entire manuscript draft as well as supervised the results-discussion. Similarly, author Dr. Sanjay Kumar Dubey has properly checked the spelling mistake, punctuation, grammatical error, conceptualization, writing, review, editing and helped in sample preparation. Both authors read and approved the final manuscript.

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Synthesis of Nano-Gold Particles for Multi-functional Finishing of Cotton Fabrics

1 Reply

DOI: 10.31038/NAMS.2023633

Abstract

Gold nanoparticles (AuNPs) were synthesized in situ on cotton, one of the most popular cellulose materials, to achieve functionalization. The localized surface plasmon resonance of the AuNPs imparted the cotton fabric with colors, showing good colorfastness to washing and rubbing. Characterization of the surface morphology and chemical composition of the modified cotton fabric confirmed synthesis and coating of the AuNPs on cotton fibers. The relationship between the morphology of the AuNPs and the optical properties of the cotton fabric was analyzed. Acid condition enabled in situ synthesis of AuNPs on cotton. Cotton with AuNPs exhibited significant catalytic activity for reduction of 4-nitrophenol by sodium borohydride, and could be reused in this reaction. Treatment with AuNPs substantially improved the ultraviolet (UV)-blocking ability of the fabric and resulted in cotton with remarkable antibacterial activity. Traditional reactive dyes were applied to the cotton with AuNPs to enhance its color features. The catalytic properties of the AuNPs on the fabric were not influenced by dyeing with traditional dyes. AuNP-treated cotton fabric used as a flexible active substrate showed improved Raman signals of dyes on the fabric.

Keywords

Gold nanoparticles, Cotton, Coloration, Catalysis, Surface-enhanced Raman Scattering, Antibacterial

Introduction

Modification of cellulose fibers, in particular cotton products, using functional nanomaterials has attracted extensive attention, with the aim of imparting properties such as antibacterial, flame retardancy, and hydrophobic properties [1-7]. Many strategies have been developed to obtain such combinations of fabric and nanoparticles, including plasma treatment, electrostatic assembly, chelation by active groups, and in situ synthesis [8-12]. Anisotropic silver nanoparticles (AgNPs) have been assembled on cotton fabric via electrostatic interaction between nanoparticles and cotton fibers, endowing the textile with bright colors due to their unique optical property, i.e., localized surface plasmon resonance (LSPR) [13]. Cotton fabric with AgNPs was also modified, followed by treatment with fluorinated decyl polyhedral oligomeric silsesquioxane (FPOSS), to fabricate colored fabric with durable antibacterial and self-healing superhydrophobic properties. AgNPs have been combined with cotton under the binding effect of branched poly(ethylenimine) (PEI) [13]. Poly-butylacrylategrafted carbon nanotubes has been applied to cotton fabric using a common dipping–drying–curing finishing procedure [14]. The modified cotton showed various functions, such as enhanced mechanical properties and extraordinary flame retardancy. Core–shell-structured silica dioxide@zinc oxide (SiO2@ZnO) nanoparticles have been prepared and adhered to cotton fabric with the assistance of (3-Aminopropyl)triethoxysilane (APTES) or vinyltriethoxysilane (VTES) [15], resulting in textiles with antibacterial activity, UVprotection properties, and high durability. Titanium dioxide (TiO2) nanoparticles have also been used for functionalization of cotton to obtain fabric with selfcleaning and UV-blocking properties [16,17]. Among functional nanoparticles, gold nanoparticles (AuNPs) have received considerable attention from researchers, owing to their promising optical, electronic, magnetic, catalytic, and biomedical applications [18,19]. As the most stable metal nanoparticles, AuNPs can be prepared using straightforward routes and are resistant to oxidation, facilitating diverse applications. AuNPs present significant catalytic activity in various reaction systems. They exhibit unique optoelectronic features and possess excellent biocompatibility with appropriate ligands as well as high surface-to-volume ratio. The properties of AuNPs including the LSPR optical effect can be readily tuned by controlling their size, shape, and surroundings. Moreover, AuNPs have been widely used as effective active substrate materials for surface-enhanced Raman scattering (SERS) analysis. The Raman signals of molecules adsorbed on AuNPs can be extremely enhanced. Modification of textile materials with AuNPs can transfer some of these important properties to the resulting textile products. Cotton is the most widely used natural fibrous material for textile and clothing production. Modification of cotton is driven by growing consumer demand for enhanced functions of conventional textile products. In situ synthesis of nanoparticles on fabric/fibers is a simple and effective route to achieve functional modification of textile materials; For example, A hydrophobic hierarchical structure has been fabricated on cotton fabric by in situ growth of silica nanoparticles [20,21]. AgNPshas been synthesized in situ on cotton fabric by adjusting the pH value at room temperature. The as-synthesized AgNPs imparted vivid colors and strong antibacterial properties to the treated fabric. TiO2 nanoparticles have been synthesized with anatase structure using ultrasonic irradiation at low temperature and loaded them onto cotton fabric [22]. The TiO2-loaded cotton fabric exhibited UV-protection and self-cleaning features. ZnO nanoparticles have been synthesized in situ in the cellulosic pores of cotton fabric by reacting zinc nitrate and sodium hydroxide to obtain fabric with antibacterial and UV-protection properties [23]. In the previous research, AuNPs were synthesized in situ on silk fabric by heat treatment [24]. This silk fabric treated with AuNPs showed not only vivid colors but also enhanced Raman signals for use as an active SERS substrate for detection of trace analytes [25]. These results inspired us to develop cotton functionalized with AuNPs by in situ synthesis. In this study, cotton fabric was modified by AuNPs synthesized in situ through heat treatment. The optical properties of the resulting colorful fabric treated with AuNPs were analyzed based on color strength (K/S) curves and ultraviolet–visible (UV–Vis) diffuse reflectance absorption spectroscopy. The surface morphology of the cotton fabric before and after modification with AuNPs was investigated by scanning electron microscopy (SEM). The influence of pH on the in situ synthesis of the AuNPs was investigated. The catalytic activity and antibacterial features of the AuNP-treated cotton fabric were evaluated. Complex coloration of cotton fabric using both AuNPs and traditional dyes was also explored. Furthermore, cotton fabric with AuNPs was used as a flexible active substrate to enhance the Raman signals of dyes on the fabric.

Technical Details

The following chemicals were used
Tetrachloroauric(III) acid trihydrate, acetic acid, sodium hydroxide, 4-nitrophenol, and sodium borohydride, Cellulose powder, CI Reactive Red 3 and CI Reactive Red 195
The textile material used was Knitted cotton fabric
The instruments used for measurement are as follows
SEM
Plasma atomic emission spectrometer
Raman microscope system
Color i7 spectrophotometer
Liquor to fabric ratio was 50: 1
The following have been followed
Colorfastness to washing
Colorfastness to rubbing
Catalytic activity
Antibacterial testing against Gram negative bacterium (Figure 1)

Figure 1: Modification of cellulose fibers

Preparation and Characterization of Gold Nano-particles

Figure 2 shows a photograph of the treated cotton fabric samples. The cotton fabric treated in 0.025 mM HAuCl4 solution (Cot-Au-1) was light red, implying presence of AuNPs on the cotton fibers. The color of the cotton fabric with AuNPs changed from light red to red to dark red as the initial concentration of HAuCl4 was increased from 0.025 mM to 0.125 mM. Based on ICP-AES, the gold content of the cotton fabric with AuNPs was measured to be 0.386, 0.725, 0.921, 1.638, and 1.849 mg g^-1 for Cot-Au-1, Cot-Au-2, Cot-Au-3, Cot-Au-4, and Cot-Au-5, respectively.

Figure 2: Treated cotton fabrics

The gold content of the samples increased as the concentration of HAuCl4 was increased. K/S curves were obtained to analyze the color changes. The peak of the K/ S curves for the treated cotton fabric remained unchanged, being located at 540 nm, with increasing gold content. However, the maximum value of the treated cotton fabric increased as the gold content was increased, consistent with its deepening color. UV– Vis diffuse reflectance absorption spectra of cotton fabric treated with AuNPs were measured. As shown in Figure 1c, a single absorption band located at 534 nm appeared in the UV–Vis absorption spectrum of CotAu-1, assigned to the characteristic LSPR mode of AuNPs. The LSPR band of cotton fabric treated with AuNPs red-shifted from 534 nm to 547 nm as the initial concentration of HAuCl4 was increased from 0.025 mM to 0.125 mM, along with an increase in the absorption band intensity. These changes in the color and LSPR property of the AuNP-treated cotton fabric may be related to the gold content, and the morphology and density of AuNPs on the cotton. SEM was employed to observe the surface morphology of the treated cotton fabric (Figure 3).

Figure 3: SEM images of a Cot-Au-1, b Cot-Au-2, c Cot-Au-3, d Cot-Au-4, and e Cot-Au-5

A number of nanoparticles were seen over the surface of fibers (Figure 2), demonstrating that AuNPs were synthesized in situ on the cotton. The size of the AuNPs on cotton was measured to be 8.7 ± 1.2, 8.6 ± 1.3, 14.1 ± 3.0, 17.4 ± 3.0, and 20.5 ± 3.8 nm for Cot-Au-1 to CotAu-5, respectively. Although the sizes for Cot-Au-1 and Cot-Au-2 were similar, Cot-Au-2 with higher LSPR intensity had higher density of AuNPs on fiber surfaces in comparison with Cot-Au-1. The size of AuNPs increased as the gold content of the samples increased as the Au ion concentration was changed from 0.05 mM to 0.125 mM. It was found that nearly all the nanoparticles on the cotton fibers were spherical for low gold content (Cot-Au-1, Cot-Au-2, and CotAu-3), whereas a few anisotropic AuNPs, such as triangular nanoplates, appeared when the gold content was increased to high level (Cot-Au-4 and Cot-Au-5). The anisotropy of the AuNPs led to the red-shift of the LSPR band observed in the UV– Vis diffuse reflectance absorption spectra of the AuNPtreated cotton fabric. As seen from the SEM images, the density of AuNPs reduced when the Au ion concentration was changed from 0.075 to 0.10 and 0.125 mM, due to generation of larger and anisotropic AuNPs. All these effects on the morphology (shape and size) and density of the AuNPs on cotton led to the changes in the LSPR property of the different samples. XPS was used to analyze the cotton fabric treated with AuNPs. XPS peaks assigned to O 1s and C 1s as the normal components of cellulose were seen in the XPS spectrum of Pri-Cot fabric. XPS peaks ascribed to Au element appeared in the XPS spectra after the cotton fabric was treated. The XPS spectrum for Cot-Au-4 displayed two principal bands at 82.2 and 85.8 eV, attributed to binding energies of 4f7/2 and 4f5/2 of metallic Au, respectively [26]. These XPS results indicate that AuNPs were successfully synthesized on the cotton fabric.

Influence of pH Value

We investigated the influence of the pH value on the in situ synthesis of AuNPs on the cotton fabric. The original pH value of the HAuCl4 aqueous solutions at 0.025–0.125 mM was around 4. The pH value of the reaction systems was adjusted by addition of acetic acid or NaOH aqueous solutions. The K/S curves and UV–Vis diffuse reflectance absorption spectra of cotton fabric treated has been obtained with 0.10 mM HAuCl4 solution at different pH values (3–6). As can be seen, the cotton fabric treated at pH 3 showed the highest K/S value of 1.71 among the different cotton samples. The K/S value of the AuNP-treated cotton fabric decreased as the pH value of the reaction system was increased. The maximum K/S decreased to 0.28 when the pH value was increased to 6. Vivid cotton fabric was obtained when using 0.10 mM HAuCl4 in the pH range of 3–6, although the cotton fabric changed slightly in color after heat treatment in HAuCl4 solution (0.10 mM) at pH 7 or above, implying that nearly no AuNPs were produced. The UV–Vis diffuse reflectance absorption bands of the cotton fabric treated with AuNPs at different pH values were centeredaround 540 nm. The intensity of the absorption bands decreased with increase in the pH value, consistent with the change trend of the K/S values. It can be inferred that acid condition facilitated in situ synthesis of AuNPs on cotton fabric, similar to the case of in situ preparation of AuNPs on ramie fibers [27]. It is well documented in literature that the pH value of the reaction system plays a vital role in formation of AuNPs through reduction of HAuCl4 [28-33]. Au ion complexes with chloride and/or hydroxide as ligands were suggested to be AuCl4 – (pH 3.3), AuCl3(OH)- (pH 6.2), AuCl2(OH)2 – (pH 7.1), AuCl(OH)3 – (pH 8.1), and Au(OH)4 – (pH 12.9) ions, corresponding to different ranges of pH [34,35]. The reduction potential of Au ion complexes depends remarkably on the pH value, with decreased reactivity as the pH is increased, in the order AuCl4 -[AuCl3(OH)-[AuCl2(OH)2 -[AuCl(OH)3 – [Au(OH)4 -. In the present study, AuNPs were synthesized in presence of cotton under acid condition, whereas Au ions were not reduced to form AuNPs in neutral or basic solution. The present results are consistent with previous analyses of the influence of pH on the formation of AuNPs. Mechanism of in situ synthesis of AuNPs It is well known that cellulose is the dominant component of cotton, consisting of long chains of Dglucose units [36]. In situ synthesis of AuNPs on cotton fabric in this study could result from reduction of Au ions by cellulose. Pure cellulose powder has been employed to reduce Au ions according to the same experimental procedure with cotton fabric. As shown in Figure S3, purplish red and grayish purple cellulose powders were produced after heat treatment in HAuCl4 solution, implying synthesis of AuNPs by cellulose. This result indicates that the reducing effect of cellulose in cotton led to in situ formation of AuNPs. Cellulose materials have been reported to act as reducing agents to synthesize AuNPs and AgNPs, owing to their abundant hydroxyl groups [37,38]. It is suggested that hydroxyl groups of cellulose play a pivotal role in the in situ formation of metal nanoparticles. The primary hydroxyl groups with higher reactivity in cellulose could be oxidized by Au ions during in situ synthesis of AuNPs. The reducing ends of cellulose in cotton could also contribute to reduction of Au ions to form AuNPs [39]. As proposed in previous research, oxygen-containing groups on the surface of cotton, including carboxylate and hydroxyl groups, can serve as active sites that might combine with AuNPs through complexing or electrostatic interaction [40]. Zeta potential measurements in our previous work indicated that cotton powder carries negative charge. It is suggested that a complexing or electrostatic interaction could lead to effective combination of synthesized AuNPs with cotton fabric in the present study. Cotton acted as a reducing agent and a stabilizing agent to prepare AuNPs on the fiber surface. Assessment of colorfastness is one of the important parameters to assess the properties and performance of textile products. The colorfastness to washing of the cotton fabric treated with AuNPs was tested by washing in presence of ECE reference detergent at 50^oC for 45 min in each washing cycle. The DE values of the treated fabric before and after washing have been determined. After the first washing cycle, the DE values were measured to be 0.7 and 2.6 for Cot-Au-4 and Cot Au-5, respectively, revealing that color fading occurred for the cotton fabric treated with AuNPs during washing. However, the DE of the treated fabric increased slightly after the third washing cycle. These results demonstrate that the cotton fabric colored with AuNPs exhibited reasonably good colorfastness to washing. In addition, the colorfastness to rubbing of the treated cotton fabric was tested. The gray scale rating for the DE values of Cot-Au-2, Cot-Au-4, and Cot-Au-5 under dry and wet rubbing conditions was assessed. The dry rubbing colorfastness was rated as 5, 4–5, and 4–5 for Cot-Au-2, Cot-Au-4, and Cot-Au-5, respectively. The rating of the wet colorfastness of Cot-Au-2, Cot-Au-4, and Cot-Au-5 was estimated to be 4–5, 4, and 4, respectively. These results show that the cotton fabric treated with AuNPs exhibited good colorfastness to dry or wet rubbing. Investigation of catalytic activity AuNPs have been widely used as catalysts for various reactions [41-43]. In the present research, AuNPs were bound to cotton fibers after in situ synthesis. As the cotton fabric acts as a support for the nanoparticles (Scheme 1), they can be readily separated from the reaction system, enabling reuse of the catalyst. Reduction of 4-NP has been commonly used as a model catalytic reaction to evaluate the catalytic activity of metal nanoparticles [44]. The catalytic activity of the cotton fabric treated with AuNPs was assessed by monitoring the UV–Vis absorption spectra of aqueous solution during reduction of 4-NP using NaBH4. The color of the 4-NP solution changed from light yellow to green–yellow after addition of NaBH4. Nitro compounds are inert to NaBH4 in absence of catalyst, whereas metal nanoparticles can act as an electronic relay agent for electron transfer from NaBH4 to nitro compounds to accelerate the reduction reaction [45]. A new UV–Vis absorption peak for 4-NP solution appeared at 400 nm after NaBH4 was added, due to formation of 4-nitrophenolate ions. The evolution of the UV–Vis absorption spectra of 4-NP solution after mixture with NaBH4 in presence of pristine cotton fabric was recorded. The intensity of the absorption peak at 400 nm for 4-NP decreased only slightly, revealing that pristine cotton fabric showed no catalytic activity. Time-resolved UV–Vis absorption spectra of 4-NP solution with NaBH4 in presence of AuNP-treated cotton fabric have been obtained (Cot-Au-1 to Cot-Au-5). The absorption peak at 400 nm of 4-NP solution decreased distinctly in intensity after addition of NaBH4 in presence of all the fabric samples treated with AuNPs. Meanwhile, a new absorption peak arose at 300 nm due to the reduction process of 4-NP, implying formation of 4-AP [46,47]. The intensity of the absorption peak at 400 nm was plotted as a function of time to determine the reduction rate of 4-NP. The rapid intensity decrease of the peak at 400 nm indicates that the cotton fabric treated with AuNPs exhibited notable catalytic activity. It was found that the reduction system with Cot-Au-4 exhibited the highest reaction rate among the AuNPtreated cotton fabric samples. Reduction of 4-NP is generally considered to be a pseudo-first-order kinetic reaction on account of excess NaBH4 [48,49]. Plots of ln(At/A0) versus time have been obtained, where At and A0 denote the absorption intensity at 400 nm at time t and the initial stage, respectively. The linear correlation between ln(At/A0) and time confirms this pseudo-first-order hypothesis. The apparent rate constant (Kapp) of the catalytic reaction can be estimated from the linear slope of ln(At/A0) versus time. The Kapp value of the reduction reaction was found to be 1.89 9 10-2, 1.76 9 10-2, 2.29 9 10-2, 4.32 9 10-2, and 2.55 9 10-2 min-1 with Cot-Au-1, Cot-Au-2, CotAu-3, Cot-Au-4, and Cot-Au-5, respectively. The Kapp values obtained in this study are comparable to related literature results for AuNPs [50,51]. Comparing these Kapp values for the AuNP cotton fabric samples, CotAu-4 with the largest Kapp value showed the highest catalytic activity, although the gold content of CotAu-4 was lower than that of Cot-Au-5. The catalytic properties of the treated cotton fabric depend on the AuNPs on the surface of cotton fibers. It is believed that the catalytic activity is related to the shape, size, and density of AuNPs on the fabric. To evaluate the reusability of the catalyst, treated cotton fabric (CotAu-4) was separated from the reaction system and reused in repeated reduction reactions of 4-NP. The peak intensity at 400 nm versus reaction time for each complete conversion is plotted in Figure 6h. The treated fabric still exhibited strong catalytic activity even after seven cycles, indicating that the treated cotton fabric exhibited durable catalytic effect. UV-protection and antibacterial properties Treatment with AuNPs endowed the cotton fabric with additional functions. The UV transmittance and UV protection factor (UPF) values of the different fabric samples have been determined. Coating with AuNPs reduced the average transmittance values of the cotton fabric. Transmittance values in both the UVA (315–400 nm) and UVB (280–315 nm) regions showed a decreasing trend with increasing gold content on the cotton fabric. The UPF value of pristine cotton fabric was measured to be 65.1, while in situ synthesis of AuNPs on the cotton fabric increased the UPF value to 109.3, suggesting that the AuNPs improved the UV-blocking ability of the cotton fabric. The antibacterial properties of AuNPs have attracted great interest, and various potential antibacterial applications have been explored [52-54]. The antibacterial activity of cotton fabric treated with AuNPs was evaluated against Gram-negative bacterium E. Coli. The bacteria on the pristine cotton fabric and treated cotton fabric have been studied (CotAu-4). A full lawn of bacteria was seen on the plates corresponding to the pristine cotton fabric, whereas no bacteria colonies were found on the agar medium of the AuNP-treated cotton fabric, revealing that presence of AuNPs on the fabric inhibited growth of bacteria. These results demonstrate that the cotton fabric with AuNPs possessed significant antibacterial activity. Dyeing of AuNP-treated cotton fabric with traditional dyes to improve the color range and saturation of the fabric, traditional dyes including R3 and R195 were used to dye the AuNP-treated cotton fabric. Dyeing with traditional dyes imparted deeper color to the cotton fabric than that achieved based on the LSPR optical effect of the AuNPs. The K/S values of the cotton fabric observably increased after dyeing with R3 and R195. Due to the light color of AuNPs at low gold content (0.386 mg g-1), the K/ S curves of Cot-R3 were almost the same as for CotAu-R3-1. The K/S curves of Cot-R195 and Cot-Au-R195-1 were also the same. However, coating with more AuNPs gave rise to higher K/S values for the cotton fabric colored with AuNPs and traditional dyes (R3 and R195). The AuNPs and dyes played a combined role in the color of the cotton fabric, even though the traditional dyes dominated the optical properties of the colored cotton fabric. Coloration using traditional dyes did not influence the catalytic properties of the cotton fabric with AuNPs. The UV–Vis adsorption spectra of 4-NP solution with Cot-R195 changed very little after addition of NaBH4, demonstrating no evident catalytic activity of Cot-R195, consistent with the case of PriCot. The intensity of the UV–Vis absorption band at 400 nm of 4-NP solution in presence of Cot-Au-R195-4 decreased sharply after NaBH4 addition, revealing that the cotton fabric after complex coloration with AuNPs and traditional dyes retained strong catalytic activity. Moreover, the cotton fabric with AuNPs and R195 could be reused in the catalytic reaction, showing significant catalytic activity after seven cycles. These results attest that the catalytic properties of AuNPs on cotton fabric are retained after coloration with traditional dyes. SERS enhancement by AuNP-treated cotton fabric AuNPs have been widely used as active substrates for enhancing Raman signals due to their LSPR effect. Raman scattering spectra were obtained to investigate the SERS enhancement effect of the AuNP-treated cotton fabric. No distinct bands were seen in the Raman scattering spectrum of pristine cotton fabric. However, visible bands were found in the Raman scattering spectra after AuNPs were coated on the cotton fabric. Evident vibrational bands were seen at 1604, 1378, 1121, 1096, 519, 457, 435, 380, and 257 cm-1 in the Raman scattering spectra of the AuNP-treated cotton fabric, being characteristic Raman bands of cotton fibers [55,56]. Some of these bands are assigned to vibrations of b-1,4-glycosidic ring linkages between D-glucose units in cellulose. It was found that CotAu-5 exhibited the strongest Raman signal of cellulose among the AuNP-treated cotton fabric samples, which may be due to the optimal morphology and corresponding LSPR effect of the nanoparticles. Noble-metal nanoparticles on textiles can enhance the Raman signals of dyes used for coloration of fibers, leading to promising applications of SERS in the field of identification of cultural heritage, forensic analysis, and textile dyeing [57-61]. In the present study, we investigated the SERS enhancement of R3 on the AuNP-treated cotton fabric. The cotton fabric dyed with R3 without AuNPs showed unclear Raman bands from cellulose units and dye on the fabric. However, enhanced Raman bands were obtained from R3-dyed cotton fabric treated with AuNPs. The R3-dyed cotton fabric with higher gold content (Cot-Au-R3-4 and Cot-Au-R3-5) showed unambiguous enhanced Raman bands. The Raman scattering spectrum of pure R3 powder has been determined. Compared with the normal Raman scattering spectrum of R3, the SERS bands from Cot-Au-R3-4 and Cot-Au-R3-5 at 284, 385, 478, 1000, 1032, 1123, 1274, 1473, and 1589 cm-1 can be ascribed to R3 dye on the AuNP-treated cotton fabric, although tiny wavenumber shifts occurred due to interactions of the dye and cotton fibers as well as AuNPs. The AuNPs on the fabric enhanced the Raman signal of the dye on the fibers, facilitating nondestructive analysis of dyes on textiles and providing insights into the dyeing mechanism of fibers.

Conclusions

Cotton fabric was functionalized by AuNPs synthesized in situ by a heating method. The fabric was colored by the AuNPs by virtue of their LSPR optical effect. The intensity of the LSPR band of AuNPtreated fabric increased with increasing gold content in the cotton samples. The treated fabric showed good colorfastness to washing and rubbing. SEM and XPS investigations confirmed the synthesis and combination of AuNPs on cotton. The mechanism for in situ synthesis of AuNPs on cotton was investigated. The fabric with AuNPs exhibited notable catalytic activity, as shown by monitoring reduction of 4-NP to 4-AP. The cotton fabric with AuNPs showed improved UVprotection and excellent antibacterial properties. Traditional dyes were combined with the AuNP-treated cotton, revealing improved color properties. The fabric with such complex coloration still exhibited prominent catalytic activity. Cotton fabric with AuNPs can also act as a SERS substrate for analysis of dyes on the fabric.

References

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On the Modelling of Heat Conduction in Crystals via Higher-grade Terms

3 Replies

DOI: 10.31038/NAMS.2023632

Abstract

The paper investigates models expressed by equations with higher-grade spatial derivatives which are devised for describing transport phenomena in nanosystems. Particular attention is addressed to the Guyer-Krumhansl equation as a prototype of equations with higher-grade terms. First the thermodynamic consistency of the equation is investigated and conclusions are found for appropriate properties of the coefficients. Next a rather new approach is developed in that evolution equations are not given from the outset but are determined by applying a representation formula that makes the consequences of the second law directly operative. In this approach the free energy, the entropy flux, and the entropy production are considered as constitutive functions that eventually generate the desired evolution equation. Some equations derived in this way prove to be highly non-linear. The approach though leads also to simple models such as the one expressedby the well-known Maxwell-Cattaneo equation.

Keywords

Heat conduction in nanosystems, Higher-grade derivatives, Non-local equations, Guyer-Krumhansl equation

Introduction

In nanoscale systems the heat carrier mean free path may result comparable with the geometric dimensions. While equilibrium properties are well established within statistical mechanics [1], the order of dimensions explains why the literature shows a deep attention to heat transport equations of non-local character at the macroscopic level (see, e.g. [2-4]). Among the approaches involved in the derivation of macroscopic equations it is worth mentioning the recourse to the Boltzmann equation [5], phonon hydrodynamics models [6] or arguments within non-equilibrium thermodynamics [7]. The thermal properties of crystals at low temperatures is often modelled by the Guyer-Krumhansl equations for heat conduction [8]. For definiteness, in the uncoupled harmonic limit the equation for the heat flux reads

where the superposed dot is the time derivative and ∇ is the gradient operator. Within continuum physics, eq. (1) can be viewed as a rate equation for q where q˙ depends linearly on q itself, a source field r and the second-grade gradients ∇∇q. Owing to the derivation within the kinetic theory and the associated approximations, it is natural to inquire about the thermodynamic consistency within continuum physics. Further, we may look for generalizations suggested by the continuum context. For instance, we may view λ, ν, ζ as constants but even more generally as temperature dependent parameters. Thermodynamically the analysis of (1) is of interest within the so called rational thermodynamics [9] also because so far investigations have been mainly performed through other approaches (see, e.g., [10]). Further, we observe that, in general, the thermodynamic restrictions involve inner products and leave the transverse (orthogonal) parts of vectors or tensors fully undetermined. The application of an appropriate representation formula allows us to look for the general structure of thermodynamically-consistent constitutive equations.This paper has a twofold purpose. First, to examine the validity of the thermodynamic consistency of rate equations like (1) with temperature dependent coefficients. Secondly, to apply the representation formula for the rate q˙ so that a generalization is given of eq.(1) and higher-grade terms, compatible with thermodynamics, are determined.

Representation Formula

The body under consideration occupies the region Ω in the three- dimensional space. Given an origin O, with any point of the body is associated a vector position x. We denote by ∇ = ∂_x the gradient operator. For any vector, say f , we define the norm |f | by |f | = (f · f )^1/2. The symbol Skw denotes the set of skew-symmetric tensors.

Let w, f be two vectors. Letting we have

2 above

If w is subject to

w · f = g (2)

then

then kinda

If the transverse part w_⊥ is undetermined then we can represent it in the form

thenkinda

where u is an arbitrary vector. Hence, in view of (2) we can represent w in the form

A number of applications of this representation formula, and of the analogous one for tensors, are developed in refs [11,12].

Thermodynamic Consistency of the Rate Equation

Let ε be the internal energy density, per unit mass, and ρ the mass density. The assumption that the body is rigid makes ρa constant. The balance of energy can be written in the form

where q is the heat flux, r is the energy supply, and the superposed dot denotes the time derivative.

Let θ be the absolute temperature and η the entropy density. The balance of entropy is expressed by

4 kinda

where k is the extra-entropy flux and is the entropy production. Substitution of ρr – ∇.q from the balance of energy (4) and using the free energy

be the set of variables. We then assume η , k, ϒ , q˙ are continuous functions of r and continuously differentiable. Indeed we first let q˙ be given by (1) and allow λ, ν, ζ depend on the temperature θ. Compute ψ and substitute in (5) to obtain

To avoid lengthy calculations we observe that replacing q˙ through (1) leads to

as far as the dependence on ∇∇θ and ∇∇∇θ is concerned. The arbitrariness and symmetry of ∇∇θ and ∇∇∇θ imply , in that

and the like for . Though not necessary we put

Thus it follows . Moreover the arbitrariness of and implies

Hence eq. (6) simplifies to

which is a restriction on the functions and λ, ν, ζ For definiteness we let

789

and is constant. Hence which is consistent with the condition Incidentally, in stationary and uniform conditions , eq. (1) reduces to the Fourier form

In light of the results (9) we infer

infer after

thus showing that the heat conductivity is required to be positive. In addition, the entropy production is

and then

Since is the specific heat, we guarantee the condition by letting

In summary, we have considered the rate equation for q, as given from the outset in the form (1), and have determined conditions for the thermodynamic admissibility. Instead, we now start with the Clausius-Duhem inequality (5) and look for possibly more general thermodynamically-consistent rate equations for q.

Generalized Rate Equations

Rate equations are now derived by appealing to the Clausius-Duhem inequality (5) and the representation formula (3). We continue to let be the set of variables and assume Hence eq. (6) reads

F 1

Since ψ, k, and ϒ are independent of then the arbitrariness of implies again the classical relation

For definiteness we keep assuming

Hence it follows that

We then apply the representation formula (3) with the identifications

Hence the general representation of q˙ is

where u is an arbitrary vector-valued function of

Models with k = 0

If k = 0 then (11) simplifies to

If also u = 0 then we can write

In one-dimensional settings (x-direction) we have

More interestingly, let Equation (12) becomes

The particular case results in

that is the Maxwell-Cattaneo equation [13,14] with relaxation time and heat conductivity

Models with K ≠ O

First we let u = 0 and observe that, by (11), in a non-linear form.

By analogy with eq. (1) we assume

where is the second-order tensor with components . Hence eq. (11) can be written in the form

Notice that

where the prime 0 means differentiation with respect to temperature.

Hence we obtain

after notice 2

If, rather, we let be constants then results in the addition of a term proportional to but also a term in the expression of q˙ . This shows the qualitative role of u in the formulation of constitutive equations. As an aside, observe that the flux is given in [15]; here the whole value of k is established by (9) subject to the constancy of

Conclusions

Models of nanosystems within continuum physics are often established by using highergrade spatial derivatives so as to account for the mean free path of particles comparable with the geometric dimensions. This paper addresses attention to the Guyer-Krumhansl equation (1) as a prototype of equations with higher-grade terms. Owing to the kinetic derivation of (1) it is natural to contrast the equation with the basic requirements of continuum physics. Here this is performed in relation to the thermodynamic consistency namely the compatibility with the second law via the Clausius-Duhem inequality. Definite conclusions are shown to follow if attention is confined to appropriate coefficients constant along with the requirements (9)).

Next a rather new approach is developed in that evolution equations are determined by applying a representation formula that makes the consequences of the second law directly operative. In this approach we consider the free energy, the entropy flux, and the entropy production as constitutive functions that eventually generate the desired evolution equation. Some equations derived in this way prove to be highly non-linear.

It seems then that this way is profitable in establishing involved higher-grade equations within continuum physics. The approach though leads also to simple models such as the one expressed by the well-known Maxwell-Cattaneo equation.

Acknowledgments

The research leading to this work has been developed under the auspices of INDAM-GNFM.

References

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Collecting Evidence and Testimonies of Severe Human Rights Violations – The Importance of the Mind

4 Replies

DOI: 10.31038/AWHC.2023621

Abstract

Especially since the recent atrocities in Ukraine and Iran, but also in Syria and China, the close interaction between psychological recovery of survivors, and efforts to investigate and prosecute severe human rights violations has become an issue of concern. Investigations and the collection of evidence, especially witness statements, are conducted by national and international authorities, including international courts, but also by NGOs and journalists. While preservation of evidence, that should be guided by the relevant UN/WMA standard, the “Istanbul Protocol” and witness statements, are an important and necessary part of such investigations, the protection of already psychologically distressed or even traumatized victims against suffering and traumatizing interviews or re-traumatization has become a concern in international, such as EU, standards, and is also mentioned in the Istanbul Protocol as reference standard, but without giving sufficient concrete guidance. Mental health is an important part in this process, as outlined in this article. An interdisciplinary working group of the World Psychiatric Association Scientific Section on Psychological Consequences of Persecution and Torture has developed and tested a new standard protocol that is recommended to be used when interviewing survivors of extreme human rights violations to address this concerns, especially in the context of the important global efforts to involve direct and indirect victims such as family members in collecting evidence as important first step in identifying, documenting, investigating and prosecuting such crimes.

Keywords

Human rights, Torture, Genocide, War, Therapeutic justice, Psychology, Victims

Human rights violations, and especially those usual described as “extreme violations” such as torture, war crimes, or genocidal actions, are not only destructive to societies, but also have been demonstrated to have severe, often lifelong impact on the mental health of individuals and communities, including transgenerational trauma transmission [1] and epigenetic sequels [2-4]. They must be seen as the probably at present most severe challenges to public mental health [5,6]. New and usually interdisciplinary strategies and interventions targeting not only individuals but communities and societies at large, might have to be developed and implemented, usually in the context of the general mental health and psychosocial services (MHPSS) approach [7,8] recommended by the UN and WHO. In spite of the development of a number of international legal and humanitarian treaty systems and instruments in humanitarian and human rights law, and of monitoring institutions such as the office of the UN High Commissioner for Human Rights, of International Criminal courts, and of offices of the UN special rapporteurs on subjects like torture, on the rights of women and children, and on genocide, the impunity of perpetrators is still a major challenge so far not sufficiently addressed in an effective way in national or international courts, except in a few exceptional cases. This means not only that the risk of future violations by the same or other perpetrators or countries must be expected to increase, but also that the suffering of victims will continue or even increase [9,10]. New strategies like the application of the legal principle of Universal Jurisdiction [11], that permits countries to prosecute, arrest and put on trial perpetrators of such extreme violations like torture or other crimes under international law, have been implemented in countries such as Germany, Austria, and France, yielding first results and conviction of some perpetrators. This must be seen as an important tool in the unfortunately common situation, that an efficient investigation and fair legal process is not possible in the country of origin of the victims who are escaping to safer third countries such as EU countries or the United States. Evidence is a strong element necessary in this process [12].

One of the key areas identified in this context, is that of an interdisciplinary approach in the collection of evidence and in the psychological support off survivors and witnesses, who must be expected to suffer by re confrontation with highly traumatic memories during witness statements, medical examination [13], and during the court hearings.

Medical evidence, including especially also psychological evidence, can play an important role in this context, and international standards such as the Minnesota protocol [14] and the recently updated Istanbul protocol (Manual on Effective Investigation and Documentation of Torture and Other Cruel, Inhuman or Degrading Treatment or Punishment) [15,16] have been developed and are supported by the United Nations and other international bodies and organisations to ensure proper procedures in examining victims and survivors. The Istanbul protocol also underlines the importance of protecting survivors during examination and during and after the witnessing and investigation process against undue distress and secondary victimisation or re-traumatization by the necessary legal interventions. In a similar way, standards by the European Union (mostly framework directives influencing the legal process in all EU countries), such as the reception guidelines for refugees or the “minimum standards on the rights, support and protection of victims of crime”, have initiated a paradigm shift to underline the importance of such psychological support and protection against secondary trauma in the necessary legal procedures besides legal recommendations.

The EU … states in article 9 of the “crime victims” directive that:

“victims of crime should be protected from secondary and repeat victimisation, from intimidation and from retaliation, should receive appropriate support to facilitate their recovery and should be provided with sufficient access to justice”.

In this context, a number of projects have demonstrated, that giving testimony about human rights violations in an adequate setting can be as or even more important than established medical treatment models or that giving testimony can improve their impact. A probably first example was the “testimony therapy” approach developed in Latin America [17,18] when a legal fight against impunity was impossible during total social control by local dictatorships. Creating a testimony or witness statement against perpetrators of torture by survivors became a key element of this special form of psychotherapy and has inspired also other new treatment approaches [19]. This is an insight that is also used on the level of communities and societies as part of a transitional justice process, for example in so-called truth and reconciliation commissions in South Africa or Rwanda [20-23], though results appear to be not always satisfactory. The discussion compares here the concepts of “restorative” vs. “punitive” justice, but in any case, impunity of perpetrators must be seen as a major challenge to survivors’ psychological health and wellbeing in whatever setting [9]. The EU Network for investigation and prosecution of genocide, crimes against humanity and war crimes (The Genocide Network), Eurojust and the Office of the Prosecutor of the International Criminal Court published on 21 September 2023 guidelines for civil society organisations, which seek to collect and preserve information to contribute to investigations and prosecutions at national level or before the ICC on “Documenting international crimes and human rights violations for accountability purposes”.

A necessary conclusion in this context is, that giving witness statements and evidence for example in proper medical examination and court testimony can be an important part of recovery and healing for survivors and witnesses [21], in addition to supporting the legal process.

Unfortunately, neither the before mentioned standard examination protocols, nor the support of survivors of extreme violence are sufficiently covered by most medical curricula.

The interdisciplinary team of the World Psychiatric Association Scientific Section on Psychological Consequences of Persecution and Torture have therefore developed a training programme and protocol to improve the psychological aspects of evidence collection and to protect witnesses and survivors during the legal process or investigation.

The protocol was applied, tested, and modified as part of a project supported by the UN Voluntary Fund for the Victims of Torture, with survivors of human rights violations from Syria and to Ukraine, in collaboration with legal NGOs active in this process and with the WPA section since 2018.

We developed a protocol focusing on the specific steps of the medical accompaniment and required psycho-social support in the context of collecting evidence and testimonies of international crimes and severe human rights violations based on our work experiences and research. In the following part of this article, we want to present this protocol for discussion and dissemination in the international medical and legal communities, considering especially the possible use in the recently started process of universal jurisdiction, International Criminal courts and the collection of evidence for example in Syria and the Ukraine. The protocol also underlines and is referring to the afore- mentioned Istanbul protocol of the United Nations and the World Medical Association, [15,16,24] and is to be seen as supporting, and not replacing this important standard, focusing on the psychological and mental health aspects of examination, witnessing and witness support.

This last aspect is important, but often neglected in forensic settings in the interaction with survivors and witnesses, who can be seen also as indirect victims, probably due to the historical focus of the forensic sciences either on the bodies, or in forensic mental health on evaluation of perpetrators, or on the evaluation of competence.

We see a psychological and/or psychiatric examination as an integral and important part of the above legal process, keeping in mind that this has to consider the stigma against mental health and the possible distress by survivors during re confrontation with traumatic memories, as also culture specific issues such as cultural idioms of distress, that can be part of the evidence [25-27]. We have summarized the key points on the importance of mental health assessment in Table 1.

Table 1: Summary: Relevance of mental health in the examination of witnesses of crimes

tab 1

Guideline and Protocol

The WPA section therefore recommends the following steps:

(Note: For the following process, we recommend an interdisciplinary approach, and installation of a well experienced and trained team)

Preparation of the case. All evidence available should be collected, and translated by lawyers, and for medical findings by the medical team (Medteam). The Medteam will analyse medical data to identify issues as mentioned in attachment I (note: here: Table 1) and familiarize team members with history and experience of the survivor/witness, in order to better prepare for testimony and examination and avoid repetition of details in the examination, to consult with experts knowledgeable of the situation and of transcultural issues, to identify experts or translators to be added to the process. The team leaders will offer legal and psychological training of the legal and medical team, including in the Istanbul Protocol.
Preparatory contact with witness, to present the team, build trust and confidence and the approach in the protocol, identify further issues as in table/attachment, agree on procedures with client, reduce stigma anxiety, provide support to locate and bring medical and other documentation, answer questions in regard to treatment and legal framework
Conduct “Welcome” meeting with support team on arrival for court hearing, psychological preparation and further rapport and trust building, if necessary or adequate in the process, medical or diagnostic interventions.
Offer support during hearings by legal, medical and psychological team members, and if necessary, organize immediate crisis intervention and medical treatment, including interventions to reduce distress. If required they will also provide advice or specific expertise to the court.
Debriefing and measures for stress reduction and relieve immediately after testimony will be offered
Follow up support including psychosocial support (following the Interagency Standing Committee (IASC) mental health and psychosocial services (MHPSS) model [28,29], provision or organization of medical support, and of further expertise as required by court, team or survivor/witness, including contact with local specialized service institutions.

Summary

Providing for mental health aspects in interacting with witnesses of human rights violations is important not only for supporting evidence collection and aiding investigation and prosecution by lawyers, but also addresses the necessary protection of often psychologically severely traumatized, vulnerable and suffering survivors and witnesses. The guideline/protocol offers concrete advice in protecting witnesses during necessary interviews and examinations, as outlined by the UN Istanbul Protocol. This approach has become even more important in the context of present wide spread violations of international humanitarian and human rights laws in Ukraine, Syria and other countries.

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Developer Goals for e-Commerce Startups: Applying AI-enhanced Mind Genomics to Thinking about Everyday Issues

5 Replies

DOI: 10.31038/PSYJ.2023553

Abstract

Mind Genomics explored responses for an e-commerce website, focusing on a website with ‘deep knowledge’ of the user’s preferences. To understand the application of Mind Genomics in a real-world setting, the timing of the setup and the fielding were limited to a total of 120 minutes. The data were collected in Spring, 2019. Four years later, newly developed AI analysis further interpreted the results. The initial analysis in 2019 deconstructed the ratings assigned by the respondents to vignettes, combinations of messages, describing the website. The respondents used an anchored 5-point scale, with the anchors ‘buy’ and ‘not buy’, respectively. The deconstruction by OLS regression revealed the contribution of each element to the ‘buy’ rating. Clustering the 46 respondents using the 16 coefficients uncovered three Mind-Sets: MS1-Help the client grow, MS2-Client Consulting, and MS3-Generate Leads. Four years later AI was applied to each group in the population, using six standard AI queries applied to all positive elements which were deemed to be strong drivers of ‘buy.’ This paper shows the possibility of rapid and insightful learning on new topics. Learning is promoted through experimental design coupled with human validation, and AI interpretation.

Introduction

The computer, the Internet, the Internet of Things, and the focus on real-time optimization continue to empower our modern age. You can’t go a single day without encountering a constant stream of ads and requests to buy. These advertisements often feature items that have already been purchased or viewed, as well as items left in a shopping cart. They are based on microsecond analyses of the shopping behavior of consumers. The analytic abilities are now so powerful that big data looks antiquated when compared to the small data generated constantly.

This paper explores what could be considered an important issue, the need to improve the flow of information between the customer and the online retailer. Online retailers function best with a large amount of data about their customers.

For roughly a decade, brands and retailers have been promoting their strategies for being “consumer centric” This means that they want to put the customer at the heart of all the work they do. In effect, this puts the consumer into the driver’s seat, with consumers ‘telling the brands’ what brand experience to create for them. When it comes to analyzing consumer behavior and preferences, retail analysts are tasked with interpreting data from consumers – such as sales figures, consumer trends and satisfaction ratings to develop insights for managing the retail enterprise profitably.

Retailers, the brands they carry, and internet service providers are increasingly criticized by privacy advocates and regulators for using data collected from consumers to develop detailed profiles on each one to tailor the commercial experience and to precisely target their messages. In response, most data collectors now offer opt-out methods to limit the data collection, its uses, and sharing with third parties, but doing so is not obvious. There is a widespread growing belief or, at the very least, a loudly expressed recognition, that data created by an individual belongs to them and should be controlled by them, similar to the requirements set forth in the EU’s 2018 General Data Protection Regulation [1].

Our world is inundated with data. As the speed and volume of data increase, our ability to form scientific questions, track trends, or subject the rapid pace of life to scientific inquiry is lost. Amidst massive amounts of data and massive optimization opportunities, it becomes increasingly hard to ‘think slow’.

We are accustomed to the slow, majestic, ingrained, now entrenched system of hypothetico-deductive reasoning [2]. It is a basic concept that scientists, or even individuals, can ‘advance,’ when they form a hypothesis and test it rigorously, trying to falsify the hypothesis. As technology speeds up the production of data and its acquisition, it is also necessary to accelerate knowledge and thought. In the harder sciences like biology and chemistry it may take exceptional creativity to produce knowledge, but in the human-centered sciences this may not be a major problem. With the advancements in computer technology, some paradigm shifts may already be possible [3].

Recurring Issues in the World of More Knowledgeable Websites

With the increasing excitement and, occasionally, almost manic positive responses about websites ‘knowing people’ comes the issue of privacy at the most obvious, but more deeply the morality of machines which have been programmed to learn about people The topic of this paper is the desire of respondents for websites (viz., provider technology) to ‘know them’, or perhaps the opposite, the fear that the machine may know too much, and the consequent loss of privacy. Some of this issue is one’s own desire for privacy, but some of it is the ‘morality’ of machine knowledge about facts relevant to individuals, and the implications of the wide availability of such knowledge. The issue is not ‘all or not’ either, for with knowledge by websites of people comes the smoother operation of interactions, the reduction of annoying, and occasionally harmful friction.

Mind Genomics: The Promise and Vision for the Future

Mind Genomics is a new, emerging science which traces back to three disciplines [4-8]. These are:

Experimental psychology which searches for the causes of human behavior. The specific area of experimental psychology giving rise to Mind Genomics is psychophysics, the discipline which searches for lawful patterns in between what is presented and what we perceive For Mind Genomics that relation is between the words describing a situation and the judgment we say we would make.
Statistics, The respondent reads combinations of elements, messages, describing this ordinary situation, and rates the feeling on a scale provided by the researcher.
Consumer research, which examines how consumers make decisions in everyday life, in which we live, work, succeed or fail. The goal is not to develop a new theory or to disprove an existing one, though these noble endeavors are possible. The only goal is to make sense of these patterns.

It is important now to keep in mind that the effort is more in the world of ‘hypothesis-generating’ than in the world of ‘hypothesis-testing.’ Quite often researchers really have no hypotheses to test but are constrained to do the study as if it were guided by a hypothesis. Mind Genomics does not care about that. It is simply a tool to discover patterns that may be interesting regarding how people think.

The process of Mind Genomics is a simple one, beginning with the question of what do people do about the information they receive as they are instructed to make a decision? Typically, the respondent is presented with the situation, using a simple story, even a single sentence. It is the goal to find regularities and relations within nature. Such discoveries generate the raw material for understanding how people think. When these discoveries are amalgamated from well-done experiments and when they reach critical mass, they form a coherent database, and in turn these coherent databases become the foundation of technology and science.

This study forms part of a new initiative in Mind Genomics which aims to massively accelerate the acquisition of information and insights for everyday life, including topics such as subjective feelings toward e-retailing, including ‘smart websites.’Another motivation is to show, through a research program integrating artificial intelligence and systematized human testing, if the two can be used to reveal aspects of everyday life or even weak signals about changing attitudes.

This study was done in 2019 before the massive expansion of AI into the world of everyday consumer research analytics. The original study was done without any focus on what AI could add to the research effort, but rather focused on what people would want for a system in which they would give up their privacy. The actual data analysis reflects what people were thinking in 2019. The subsequent AI analysis, in turn, was done in the third week, of May 2024, with a view to what the data might mean for a business issue.

The project itself in each phase ran on an accelerated schedule. For the first part of the project, the actual research, the total time involved was less than three hours from start of the project (create the experiment) to the acquisition of analyzed data. For the second part of the project, the AI analysis of the results obtain four years before, the analysis took 30 minutes, consisting of an automated AI-driven reanalysis of the data tables The actual study itself with people came shortly after the first experience integrating AI and Mind Genomic by hand, with AI providing the raw information first, that information transformed into the test stimuli [9]. The effort presented here moves the process in the opposite direction, with AI providing a second, deep analysis of results already obtained.

The First Part of the Project – The Creation and Execution of the Survey with the Respondents

Mind Genomics is now scripted. It follows a templated process which reduces the “angst” of doing experiments as well as the time and effort required to collect data. Experience over a half century has shown that individuals are anxious when asked to “do science.

Mind Genomics scripts are designed to make sure that researchers can present the information in the correct format. In the actual experiment, relevant messages about a subject (called “elements”) are combined into short, easily readable vignettes. A vignette consists of 2-4 messages. People then rate the combinations using a scale. Each respondent ends up rating 24 different vignettes. The vignettes are different for each respondent, but all the elements remain the same [10].

Mind Genomics’ studies have been scripted to allow them to be run on a computer, smartphone, or tablet, with results available in a very short time. The information in Table comes from the study, text taken from the actual input by the researcher, and put together in the report to document the study. The information in Table 1 is available within five minutes after the end of the study, as is the basic analysis. The AI summarization requires an extra 20-30 minutes after the end of the field work. (Table 1)

Table 1: Key information about the study provided by the Excel report.

The setup begins with naming the study and the instructions to provide four questions relevant to the topic of study. Researchers are asked to structure four questions in a way that they “tell a story,” and then provide four answers to each question. Figure 1 shows the template. In 2019, it took several hours to create the four questions for each question and four answers.

Figure 1: The templated request of four questions (left panel) and four answers as used by respondent to manually provide questions and answers.

Since Mind Genomics became available to the public more than 10 years ago as a DIY (do it yourself) technology, there have been many instances where researchers felt overwhelmed with the task of creating the elements.

It is now possible to use artificial intelligence to generate questions. The researcher only needs to write a paragraph into the Idea Coach box in the Mind Genomics template and the AI will return 30 different questions. The Idea Coach technology, which was launched in 2022, was three years after this study was conducted.

Figure 2 shows three additional set up screen shots from BimiLeap. These include the orientation page (left panel), the rating scale (middle panel), and the researcher’s file information about the rationale for the experiment as well as key words for a later search (right panel).

Figure 2: Three setup screen shots for BimiLeap. These are the orientation page (left panel), the rating scale (middle panel) and the file information (right panel).

The researcher can select the respondents’ source using the screen in Figure 3 following the study’s launch. This is done quickly within the BimiLeap software. Respondents are ‘sourced from’ a panel provider that specializes in online surveys. There are a number of panel providers around the world. These panel providers maintain lists of respondents with their qualifications. They are individuals who have agreed, in exchange for a reward from the supplier, to take part in similar studies. The researcher does not need to know about the agreement. The panel provider only needs to find the right respondent.

Figure 3: Sources of respondents selected by the researcher at the end of the project.

Mind Genomics research can include elements (questions, answers, etc.) in many different languages and alphabets. However, the instructions on how to set up the study as it is done by the researchers are only available in a limited number of languages.

The actual experiment with the subject lasted about 3 minutes. The experiment starts with a brief orientation. The respondent then answers a few self-profiling questionnaires (Figure 4, bottom panel). Finally, the BimiLeap program presents 24 different vignettes that have been systematically created. The vignettes contain 2-4 elements, at most one answer to a single question but often no answer to one or two of the questions (see Figure 4, top panel).. It will be this very incompleteness of the combinations which allows the analysis by OLS (ordinary least-squares), and the estimate of absolute values for the coefficients.

Figure 4: Sample four-element vignette (top), and self-profiling classification (bottom).

The experimental design allows for the analysis of each individual’s ratings, respondent by respondent, as well as analysis of groups comprised of any set of 46 respondents who participate in this study. The vignettes have been set up in a way that each person evaluates 24 unique vignettes. This design structure allows the researcher to explore different aspects of a problem without having to select which combination of elements gives the best chance for discovery.

Database Structure, Analysis, and Reports – Total Panel

It is easy to analyze the data because the experiment design has been preselected in a way that all the 24 combinations of different sets are isomorphs. The vignettes are different, but the mathematical structure is identical. The researcher will have a powerful analytical tool that allows them to explore a large part of the “design space” (the combinations). More respondents, and therefore more people, means that more design space will be covered.

A simple database makes it possible to perform the analysis. The database is divided into 24 rows, each of which corresponds with one of the vignettes that a respondent has tested. The database for the study contains 1104 rows, or 46×24, of data. Each respondent contributes 24 rows to the database, one row for each of the 24 vignettes evaluated by that respondent. The Columns are allocated for bookkeeping (row number, how the respondent profiles herself or himself), a column for the order of rating of the 24 vignettes (1-24), then 16 columns to show absence or presence (value 0 or 1) of an element, and finally the assigned rating and the response time. The response time is the number of seconds between the appearance of a vignette and the answer.

The program then creates two binary variables: TOP (ratings 5, 4 transformed into 100) and BOT (ratings 1, 2 and 4 transformed into 100). BimiLeap adds a vanishingly small number of random numbers for each BOT or TOP value to create needed This prophylactic measure ensures the required variability, even if the respondent rates all the vignettes as either 5 or 4 (all transformed TOP become 100) or 1 or 2 (all transformed BOT become 100).

Table 2 shows the parameters of the equation, expressed as: TOP = k0 + k1A1 + k2A2 .. k16D4 . This equation can be estimated accurately because the OLS regression does not have any correlation issues between variables. The coefficients emerging from the OLS are absolute values, so a 5 has half of the value as a 10 It is crucial to understand this necessary property, which allows Mind Genomics to create a science. The researcher can quickly grasp the dynamics in the data revealed by the experiment when the coefficients show the real magnitude of the effects.

Table 2: Elements for the Total Panel which drive TOP (Sounds interesting). Only elements with coefficients > 1 are shown.

As a side note, this vision of absolute coefficients is often counter-intuitive to ‘experts’ who believe that the respondent needs all the information from the different questions to make a decision. Admirable as that point of view is, which ends up presenting complete vignettes to each respondent, the results data is almost impossible to understand, because the absolute coefficients have no meaning. It is only differences which have meaning. There is no possibility of databasing the results unless the entire study is replicated. Only then do the coefficients have meaning.

Table 2 shows the results from the Total Panel, of 46 respondents, each rating a unique set of 24 vignettes. The Table shows us places for the 16 coefficients, along with the additive constant.

This constant indicates the likelihood of respondents saying ‘buy’ in the absence of any element in the vignette. The vignettes are all designed with a minimum of two and maximum four elements. The additive constant can be thought of as a statistical correction factor. On the other hand, we can use this as a base, or a tendency for respondents to respond “buy”. This will help us gain this insight. Table 2 indicates that 45% of the responses will be 5 or 5, when they know what the system is, even when there are no specific elements to qualify the product. We could have measured this change over the years if we had done the same type of experiment.

In the interests of revealing patterns, the convention in this paper and others is to show only positive coefficients of value 2 or higher. Coefficients of 1, 0 and negative are of no interest. The low coefficients indicate that an element’s presence in a vignette “doesn’t add”. This does not necessarily mean the element detracts or is insignificant.

Eight out of 16 elements have coefficients greater than 1. All the rest generate coefficients that are 0 or negative. . However, only one element is really successful, “create amazing ads” with a coefficient of 6. Subgroups are likely to be hiding strong performers, as we shall soon see.

We now move to the AI interpretation of these results from the total panel. AI analysis should only be viewed as a set of tentative observations by a heuristic. AI can provide a quick answer before taking the time to analyze the entire dataset. The BimiLeap report has been upgraded to provide AI responses to the following six queries, using the coefficients for the key subgroup being summarized.

The following are the six queries.

Interested in

Create a label for this segment:

Describe this segment:

Describe the attractiveness of this segment as a target audience:

Explain why this segment might not be attractive as a target audience

Which messages will interest this segment

These queries primarily consider moderate or high performing elements with coefficients greater than +5. The elements with coefficients below 4 are considered, but not relied upon.

The AI summarization of the data, based on the six queries appears in Table 3.

Table 3: AI first scan and interpretation of the strong performing elements for the Total Panel.

Results from Self-profiling Questionnaire

The BimiLeap program instructed respondents to put themselves into one of four groups, based upon how they feel about an outside website having deep knowledge of oneself. Table 4 shows the pattern of coefficients generated by the two polar opposite groups, the first very excited and positive about the situation, the second bothered. As one might expect, the additive constants are higher for the positive group, and much lower for the negative group. Furthermore, there are more strong-performing elements in the positive group. Table 4 shows the coefficients of the elements. Table 5 shows the AI analysis of the patterns.

Table 4: Elements which drive TOP (Buy) for the two key segments emerging from the self-profiling question: How important is it that the website know my mind to give me offers?

Table 5: Elements which drive TOP (Buy) for the three Mind-Sets, emerging from k-means clustering of all the element coefficients from the 46 respondents.

Dividing Respondents According to Mind-Sets Using the Coefficients

The final analysis of the data will be focused on creating Mind-Sets. These are groups of respondents that have been created by using the K-means Clustering Program based upon the similarity of the patterns made by their coefficients. We use the 16 coefficients whether they are positive or negative for clustering. The additive constant is not used in clustering [11].

BimiLeap. It generates two Mind-Sets at first, then three Mind-Sets. The Mind-Sets encompass all respondents. A person belongs to only one mind-set for the two mind-set solution, and again to only one mind-set for the three mind-set solution. The clustering results in meaningful groups that can be interpreted, despite the fact that the process is mechanical and mathematical.

Table 6 lists the elements that make up the successful performance of the Three-Mind-Solution. In order to save space, the two-mind solution is not included. The AI results are shown in Table 7, emerging after applying the six AI queries to the Mind-Sets.

Table 6: AI interpretation of the strong performing elements) by AI for the three-Mind-Set solution.

Table 7: The IDT, Index of Diverged Thought, showing the performance of the elements, and thus the strength of the thinking behind the specific Mind Genomics study.

Understanding Performance Using an Index Number (IDT, Index of Divergent Thought)

Researchers in many fields ask the same question: “How did we perform?” With Mind Genomics and AI still at an early stage, but available worldwide at the touch of a button, it becomes a matter of whether the research produced anything valuable. It is important to note that the notion of “value” does not refer to personal worth of data for the researcher or to reproducibility of science. Instead, for Mind Genomics we ask whether or not the study produced any high-performing elements. When we find strong elements, there’s a link between the element and rating questions. In these studies, the researchers are looking for this link. In those elements, the issue at hand can be better understood.

We present IDT Index of Divergent Thought as part of our effort to “systematize” the use of Mind Genomics, in an era of simple-to-use AI-powered techniques. IDT’s objective is to determine the effect of elements. IDT produces a simple, indexed result. This is shown in Table 8. When we divide the study into six groups, each sum of positive coefficients for that group is weighted by the relative number of respondents for that group. The six groups are Total, Mind-Sets 1 & 2 for the 2-Mind-Set solution, and Mind Sets 1, 2, & 3 for the 3-Mind-Set solution. The IDT is the weighted sum of positive coefficients. The weight is the ratio between the respondents per group and the total of 138.

The IDT by itself is simply an index number about how well the elements performed. With continuing use of the IDT as a metric, it may become possible to measure the degree to which a person grows in the ability to think creatively. One could imagine charting the IDT value for a person or group of people as they are challenged to think through various problems. The IDT gives us a way of measuring the ‘strength’ of alternative efforts to deal with the same issue, with different issues, after teaching interventions, and so forth. The alternatives may be the same researcher over time, the performance of studies done by individuals vs. those done by collaborating groups, and so forth. The IDT is objective, a simple index quickly calculated as part of the report to the researcher.

Discussion and Conclusions

The Mind Genomics method has been used to investigate the decision-making process for the world of the ‘everyday.’ Rather than focusing on topics of deep significance and with a long history of investigation, the researcher using Mind Genomics investigates simpler problems, such as what does a person want from a website which ‘knows’ the user. It is within that world view that the current study was done.

What emerges from Mind Genomics is far more than a simple snapshot of human decision making at the level of the concrete issue. One can sense from the use of commonplace features as elements that behind these everyday statements lay an entire universe of motivations, a universe that might totally disappear or at least lose its vitality if the statement were couched in the general, rather than in the specific. It is the richness in the meaning of everyday experience which provides deep learning. In other words, Mind Genomics provides emotion-rich, philosophically rich metaphors that ordinary, academic language cannot.

Armed with that point of view the paper no longer talks only about websites which know the person. Rather, the paper talks to the issue of emotional responses to different ways of weighting information to decide. different ways of responding to recommendations from a ‘machine’ and the concern with the nature and trustworthiness of machines which know the person. The issues lose a bit in the translation when they are stated in the form of generalities, but create immediate, palpable internal sensations when they are described by daily, identifiable events, viz., by realistic metaphors.

Beyond the actual data from the Mind Genomics exercise, however, lies the second layer of AI analysis. The AI process was told to look at the elements in general, especially those with coefficients of +6 or higher, along with the additive constant, and summarize the results through six queries. The objective of the exercise was to publicly present the data, and then the AI interpretation of the data, untouched by human hands. No attempt was made to structure the output of the AI, this effort being among the first to attempt a machine-level summarization. It is likely that we will see significant advances in ‘insights and languages, as the ever-evolving AI amplifies the structured outputs of Mind Genomics experiments.

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