ABSTRACT
Device-level implementation of soft materials for energy conversion and thermal management demands a comprehensive understanding of their thermal conductivity and elastic modulus to mitigate thermo-mechanical challenges and ensure long-term stability. Thermal conductivity and elastic modulus are usually positively correlated in soft materials, such as amorphous macromolecules, which poses a challenge to discover materials that are either soft and thermally conductive or hard and thermally insulative. Here, we show anomalous correlations of thermal conductivity and elastic modulus in two-dimensional (2D) hybrid organic-inorganic perovskites (HOIP) by engineering the molecular interactions between organic cations. By replacing conventional alkyl-alkyl and aryl-aryl type organic interactions with mixed alkyl-aryl interactions, we observe an enhancement in elastic modulus with a reduction in thermal conductivity. This anomalous dependence provides a route to engineer thermal conductivity and elastic modulus independently and a guideline to search for better thermal management materials. Further, introducing chirality into the organic cation induces a molecular packing that leads to the same thermal conductivity and elastic modulus regardless of the composition across all half-chiral 2D HOIPs. This finding provides substantial leeway for further investigations in chiral 2D HOIPs to tune optoelectronic properties without compromising thermal and mechanical stability.
ABSTRACT
A novel hyper cross-linked polymer of 2-Aminobenzoic acid (HCP-AA) is synthesized for the adsorption of Cr3+ and CO2. The Brunauer-Emmett-Teller surface area of HCP-AA is 615 m2 g-1. HCP-AA of particle size 0.5 nm showed maximum adsorption of Cr3+ for lab prepared wastewater (93%) while it was 88% for real industrial wastewater. It is might be due to electrostatic interactions, cation-π interactions, lone pair interactions and cation exchange at pH 7; contact time of 8 min; adsorbent dose 0.8 g. The adsorption capacity was calculated 52.63 mg g-1 for chromium metal ions at optimum conditions. Freundlich isotherm studies R2 = 0.9273 value is the best fit and follows pseudo second order kinetic model (R2 = 0.979). The adsorption is found non-spontaneous and exothermic through thermodynamic calculations like Gibbs free energy (ΔG), enthalpy change (ΔH) and entropy change (ΔS) were 6.58 kJ mol-1, - 60.91 kJ mol-1 and - 45.79 kJ mol-1 K-1, respectively. The CO2 adsorption capacity of HCP-AA is 1.39 mmol/g with quantity of 31.1 cm3/g (6.1 wt%) at 273Kwhile at 298 K adsorption capacity is 1.12 mmol/g with quantity 25.2 cm3/g (5 wt%). Overall, study suggests that carboxyl (-COOH) and amino (-NH2) groups may be actively enhancing the adsorption capacity of HCP-AA for Cr3+ and CO2.
ABSTRACT
Individuals working in diverse fields are consistently exposed to work-related pollutants that can impact their overall health. The current study investigated the presence of pollutants in seven different occupational groups and their impact on human health. Biochemical and genetic approaches were employed. Heavy metals were determined by ICP-MS technique. Oxidative stress biochemical markers and molecular analysis of the glutathione transferases gene SNPs (GSTT1, GSTM1, GSTP1), catalase (CAT, rs7943316), and superoxide dismutase (SOD, rs17880487) was carried out. The results revealed a significantly higher quantity of Cd among five occupational groups. Catalase, malonaldehyde, and glutathione was significantly dysregulated. Molecular analysis of the gene SNPs suggests a probable relationship between the antioxidants and the phenotypic expression of the CAT, GSTP1, GSTT1, and GSTM1 SNPs. It is concluded that chronic exposure to occupational contaminants like Cd affects human health through oxidative stress in association with some of their gene SNPs.
Subject(s)
Catalase , Glutathione S-Transferase pi , Glutathione Transferase , Metals, Heavy , Occupational Exposure , Oxidative Stress , Polymorphism, Single Nucleotide , Superoxide Dismutase , Humans , Glutathione Transferase/genetics , Catalase/genetics , Glutathione S-Transferase pi/genetics , Metals, Heavy/toxicity , Superoxide Dismutase/genetics , Adult , Male , Antioxidants/metabolism , Malondialdehyde , Glutathione/metabolismABSTRACT
For heat conduction along polymer chains, a decrease in the axial thermal conductivity often occurs when the polymer structure changes from one-dimensional (1D) to three-dimensional (3D). For example, a single extended aliphatic chain (e.g., polyethylene or poly(dimethylsiloxane)) usually has a higher axial thermal conductivity than its double-chain or crystal counterparts because coupling between chains induces strong interchain anharmonic scatterings. Intuitively, for chains with an aromatic backbone, the even stronger π-π stacking, once formed between chains, should enhance thermal transport across chains and suppress the thermal conductivity along the chains. However, we show that this trend is the opposite in poly(p-phenylene) (PPP), a typical chain with an aromatic backbone. Using molecular dynamics simulations, we found that the axial thermal conductivity of PPP chains shows an anomalous dimensionality dependence where the thermal conductivity of double-chain and 3D crystal structures is higher than that of a 1D single chain. We analyzed the probability distribution of dihedral angles and found that π-π stacking between phenyl rings restricts the free rotation of phenyl rings and forms a long-range order along the chain, thus enhancing thermal transport along the chain direction. Though possessing a stronger bonding strength and stabilizing the multiple-chain structure, π-π stacking does not lead to a higher interchain thermal conductance between phenyl rings compared with that between aliphatic chains. Our simulation results on the effects of π-π stacking provide insights to engineer thermal transport in polymers at the molecular level.
ABSTRACT
Chronic exposure to electronic waste (e-waste) is becoming a serious concern for health among individuals exposed to it. E-waste has been reported to contain heavy metals, trace elements, and persistent organic pollutants which can trigger health issues through different biological pathways. The liver is a major metabolic and detoxifying organ in the body. Glutathione S-transferase (GST) is a liver enzyme for phase II detoxification that catalyzes glutathione (GSH) conjugation with environmental pollutants. This research aimed to investigate the liver toxicity caused by long-term exposure to e-wastes, exploring the potential association with null variants of GSTT1 and GSTMI, as well as GSTP1. The study was designed as a cross-sectional investigation, in which 256 adult males who were chronically exposed to e-waste and 200 non-exposed control participants, matched for age and gender, were recruited randomly. Standard colorimetric and enzymatic methods were used to analyze biochemical parameters such as serum alkaline phosphatase (ALP), alanine transaminase (ALT), total bilirubin (T. Bil), albumin, and reduced glutathione. Genotypic analysis of the null variant GSTM1, GSTT1, and GSTP1 genes was conducted by standard molecular methods. The study findings indicated a notable surge in ALP, ALT, and albumin levels while T. Bil and GSH levels showed a reduction, suggesting a potential risk of liver toxicity. Additionally, analysis of GSTM1, GSTT1, and GSTP1 genotypes revealed a possible association with GSH levels and the hepatotoxicity risk. The study concluded that the individuals exposed to e-waste exhibited dysregulation of liver enzymes that results in liver toxicity. Moreover, analysis of GSTM1, GSTT1, and GSTP1 at a molecular level revealed that these genes could potentially serve as risk factors for liver toxicity in e-waste chronic exposure.
Subject(s)
Electronic Waste , Male , Adult , Humans , Polymorphism, Genetic , Cross-Sectional Studies , Genetic Predisposition to Disease , Glutathione Transferase/genetics , Glutathione S-Transferase pi/genetics , Genotype , Risk Factors , Liver , Case-Control StudiesABSTRACT
Liquid heliums are intriguing substance. Superfluid states below certain critical temperatures, notably liquid helium-4 and helium-3 exhibit ultra-high thermal conductivity ( TC) in the superfluid phase. However, the microscopic origin of the TC of liquid heliums in the normal phase remains unclear. In this work, we employ the thermal resistance network model to calculate the thermal conductivities of normal liquid helium-4 (He I) and helium-3. Predicted values are not only in good agreement with the measurements but also reproduce the experimental trend of TC increasing with temperature and pressure.
ABSTRACT
Forecasting household assets provides a better opportunity to plan their socioeconomic activities for the future. Fractional mathematical models offer to model the asset-holding data into a piece of scientific evidence in addition to forecasting their future value. This research focuses on the development of a new fractional mathematical model based on the wealth index quintile (WIQ) data. To accomplish the objective, we used the system of coupled fractional differential equations by defining the fractional term with the Caputo derivative and verified it with the stability tests considering the steady-state solution. A numerical solution of the model was obtained using the Adams-Bashforth-Moulton method. To validate the model, we used real-time data obtained from the household series of surveys in Punjab, Pakistan. Different case studies that elucidate the effect of quintiles on the population are also presented. The accuracy of results between real-world and simulated data was compared using absolute and relative errors. The synchronization between the simulated results and real-time data verifies the formulation of the fractional WIQ model. This fractional model can be utilized to predict the approximation of the asset-holding of the households. Due to its relative nature, the model also provides the opportunity for the researchers to use the WIQs of their respective regions to forecast the households' socioeconomic conditions.
Subject(s)
Family Characteristics , Projection , Models, Theoretical , Data Collection , PakistanABSTRACT
BACKGROUND: The advent of the pandemic COVID-19 has resulted in a global crisis that resulted in the closure of universities and educational institutions worldwide. This study aims to explore the determinants of students' intention towards e-library services usage amid the challenging time of the COVID-19 pandemic. This paper reviews the technology-oriented individual attitude based on four dimensions of the technology readiness 2.0 index factors, which affect medical students' perspectives. MATERIALS AND METHODS: The authors provided a self-administered questionnaire to medical students to investigate their e-library adoption attitude during the COVID-19 crisis. The authors distributed 542 questionnaires, received 361 complete responses and analyzed the data through path modeling/partial least squares structural equations modeling technique (PLS-SEM) with the smart PLS software version 3.3.3. The structural equation-modelling tool permits the estimation of results. RESULTS: The main finding revealed that medical students have a positive and explicit approach to use the services available at the e-library. Technology use and online services helped students continue their educational needs in the advent of the current pandemic COVID-19. Attitude and subjective norms have significant influence and are strong predictors of intention. However, due to inadequate support for the government side, the perceived behavioural control has an insignificant impact on intention. This paper indicated one of the pioneers investigating the determinants of e-library adoption among medical students based on technology-oriented personality traits, employing the four dimensions of the technology readiness 2.0 index during the challenges of the COVID-19 outbreak. CONCLUSION: The study's findings provide useful insight that offers valuable insights to implement specific strategies from the government officials to address medical students' uncertainties and increase the technology adoption amid the COVID-19 pandemic in medical education for developing nations.
ABSTRACT
Better socioeconomic status and well-being in households decrease malnutrition and health risks in children. The objective of the present study is to assess the current nutritional status of pre-school children and to correlate the prevalence of malnutrition with Household Deprivation Status (HDS) in one of the deprived districts of the Punjab province in Pakistan. Using primary data collected from 384 households through a proportional purposive random sampling technique, this study calculates the z-scores of weight-for-age (WAZ), weight-for-height (WHZ), and height-for-age (HAZ). The study has used a cut-off point which is -2 standard deviations below the median of the WHO/NCHS reference population for each anthropometric indicator. The results indicate that the underweight, stunting, and wasting prevalence rates are 46.1%, 34.83%, and 15.49% respectively in district Rahimyar Khan. Also, the expected tendency of malnutrition is worst for HDS-1 and HDS-2 which are the most deprived segments of the population. As the household shifts from HDS-1 to HDS-2 and further to HDS-3, the rates of stunting (HAZ) and underweight (WAZ) decreases but wasting (WHZ) does not. The study concludes that the high prevalence of malnutrition in the district is correlated with overall socio-economic deprivation.
Subject(s)
Child Nutrition Disorders , Malnutrition , Child , Child Nutrition Disorders/epidemiology , Child, Preschool , Growth Disorders/epidemiology , Humans , Infant , Malnutrition/epidemiology , Nutritional Status , Pakistan/epidemiology , Poverty , Prevalence , Thinness/epidemiologyABSTRACT
Maternal nutritional awareness might reduce the risk of malnutrition in children. This study assesses the impact of mothers' nutritional and health awareness (MNHA) on the nutritional status of pre-school children in rural South Punjab. Using a proportionate purposive simple random sampling technique we collect data with the help of a self-administered questionnaire on height, age, the weight of children, and socio-economic profile from 384 rural households in one of the marginalized districts of Punjab. The study applied the binary logistic regression model to compute the probability of malnutrition. The results indicate that malnutrition was high in the district (the prevalence rate for underweight is 46.1%, for stunting 34.83%, and for wasting is 15.49%). Around 91.84% of malnourished children belonged to the low MNHA category compared to medium (5.61%) and high (2.55%) MNHA categories. The results further show that the prevalence of moderate and severe stunting, wasting, and underweight in low MNHA categories was much higher with large differences compared to both medium and high MNHA categories. The binary logistic regression results depict that, across the household deprivation index (HDS), the odds of a child becoming malnourished were lower in households HDS-2 category (OR = 0.02, 95% CI: 0.01-0.89), and odds were also lower in households HDS-3 category (OR = 0.001, 95% CI: 0.001-0.16). Similarly, across the scores of MNHA index, the odds of malnutrition were lower among the children of those mothers who had medium MNHA (OR = 0.04, 95% CI: 0.002-1.24), and also the probability of child malnutrition was lower among the children of mothers who had high MNHA (OR = 0.008, 95% CI: 0.002-0.29). The study urges that well-resourced, targeted, and coordinated health and nutritional education and awareness programs are required to tackle malnutrition.
Subject(s)
Child Nutrition Disorders , Malnutrition , Child , Child Nutrition Disorders/epidemiology , Child, Preschool , Female , Growth Disorders/epidemiology , Humans , Malnutrition/epidemiology , Mothers , Nutritional Status , Pakistan/epidemiology , Rural Population , Thinness/epidemiologyABSTRACT
The present study aimed to investigate the effects of fear of COVID-19 and situational depression on the quality of life (QOL) of Pakistani citizens. An online cross-sectional survey was conducted on Pakistani citizens via the snowball sampling technique. A total of 377 respondents (256 males and 121 females) participated in this study from August to October 2020. Adapted scales were validated using confirmatory factor analysis, and partial least squares structural equation modelling (PLS-SEM) was applied to the data to test the hypothesised model. The study's findings showed a negative relationship between fear of COVID-19 and QOL. Likewise, a reciprocal relationship was found between situational depression and quality of life. The results indicate that fear of COVID-19 and situational depression during the pandemic have affected the lives of Pakistani citizens. The findings are particularly relevant for improving the QOL by limiting the information received from media and social networks. There is a need to control these mediums and promote community-based interventions to provide accurate knowledge regarding COVID-19. Fear of COVID-19 and situational depression may be reduced in this way. Based on the current findings, psychotherapy and counselling programmes must be planned to minimise the adverse effects of fear of COVID-19 and depression on the QOL of citizens due to the ongoing progression of the pandemic.
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This study emphasized the relationship between the Chinese companies' product market competition and organizational performance. This article explored the mediating effect of capital structure and the moderating impact of firm size in achieving better performance of Chinese companies. This study employed a sample of 2,502 Chinese firm observations and identified that market competition positively influenced firm performance. Additionally, capital structure partly mediated the relationship between product market competition and firm performance. Similarly, the present study also tested the moderating effect of firm size (both small and large) on the association between product market competition and firm performance. The results showed that moderating large businesses affects the nexus between product market competition and firm performance. Conversely, small firms' moderating role revealed a substantial adverse impact on the association between product market competition and firm performance. These findings contribute to the literature on the complex implications of market competition on business firms' performance. The results provide insightful and practical implications for future research directions.
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The study stipulates phases to observe the proposed mechanism in formulating the travel and leisure industry's recovery strategies. The present pandemic COVID-19 has resulted in global challenges, economic and healthcare crises, and posed spillover impacts on the global industries, including tourism and travel that the major contributor to the service industry worldwide. The tourism and leisure industry has faced the COVID-19 tourism impacts hardest-hit and lies among the most damaged global industries. The leisure and internal tourism indicated a steep decline amounting to 2.86 trillion US dollars, which quantified more than 50% revenue losses. In the first step, the study explores the consequences and settings of the COVID-19 pandemic and how innovation and change can contribute to the tourism industry's revival to the next normal. Thus, the study determines that tourism enterprises and scholars must consider and change the basic principles, main assumptions, and organizational situations related to research and practice framework through rebuilding and establishing the tourism sector. In the second step, the study discusses direct COVID-19 tourism impacts, attitudes, and practices in gaining the leisure industry's boom and recovery. In the third phase, the study proposes to observe the characteristics and COVID-19 tourism consequences on the travel and tourism research. The findings provide insights in regaining the tourism industry's operational activities and offer helpful suggestions to government officials, scholars, and tourism firms to reinvest in the tourism industry to set it back to a normal position.
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Organophosphates (OP) are a major agrochemical. The application of OP pesticides is expected to increase multifold in the coming decades. The etiology of diabetic diseases is attributed to multiple factors including OP pesticide exposure. The present study investigates pancreatic dysregulation with respect to exocrine enzymes and diabesity in groups of Pakistani and Cameroonian people exposed to a mixture of OP pesticides. Nine hundred and four OP exposed individuals were enrolled for this cross-sectional study after due consent and approval from an ethical review committee. Pesticides' residues were measured by GC-MS spectrometry. Cholinergic enzymes were measured by Elman's method. Serum glucose, insulin, serum amylase, lipase, and triglyceride were measured by spectrophotometry and ELISA; HOMA-IR was determined in OP exposed and non-exposed participants. Stata 15 and R 3.2.0 software were used for statistical analysis of the data. Malathion, chlorpyrifos, and parathion residues were evident in plasma samples. RBC-acetylcholinesterase was significantly depressed in OP exposed groups. In both population samples, investigated pancreatic functions were found to be statistically significantly more dysregulated than non-exposed. OP exposure indicated risk of diabetes and insulin, glycaemia, adiponectin, triglycerides, and TNF-α dysregulations. The study concludes that both OP exposed population groups exhibited a mixture of OP residues and pancreatic dysregulation, although the effect was more pronounced in the Cameroonian population. In addition, serum lipase has a positive correlation with OP exposure and diabetes and may be suggested as an alternate/additional diagnostic marker for diabesity under OP exposure. However, screening of other environmental co-factors with OP for pancreatic dysregulation is suggested.
Subject(s)
Chlorpyrifos , Insecticides , Pesticides , Cross-Sectional Studies , Humans , Organophosphorus Compounds , Pesticides/toxicityABSTRACT
The detrimental effects of organophosphates (OPs) on human health are thought to be of systemic, i.e., irreversible inhibition of acetylcholinesterase (AChE) at nerve synapses. However, several studies have shown that AChE inhibition alone cannot explain all the toxicological manifestations in prolonged exposure to OPs. The present study aimed to assess the status of antioxidants malondialdehyde (MDA), superoxide dismutase (SOD), glutathione (GSH) (reduced), catalase, and ferric reducing antioxidant power (FRAP) in chronic OP-exposed groups from Cameroon and Pakistan. Molecular analysis of genetic polymorphisms (SNPs) of glutathione transferases (GSTM1, GSTP1, GSTT1), catalase gene (CAT, rs7943316), sirtuin 1 gene (SIRT1, rs10823108), acetylcholinesterase gene (ACHE, rs2571598), and butyrylcholinesterase gene (BCHE, rs3495) were screened in the OP-exposed individuals to find the possible causative association with oxidative stress and toxicity. Cholinesterase and antioxidant activities were measured by colorimetric methods using a spectrophotometer. Salting-out method was employed for DNA extraction from blood followed by restriction fragment length polymorphism (RFLP) for molecular analysis. Cholinergic enzymes were significantly decreased in OP-exposed groups. Catalase and SOD were decreased and MDA and FRAP were increased in OP-exposed groups compared to unexposed groups in both groups. GSH was decreased only in Pakistani OPs-exposed group. Molecular analysis of ACHE, BCHE, Catalase, GSTP1, and GSTM1 SNPs revealed a tentative association with their phenotypic expression that is level of antioxidant and cholinergic enzymes. The study concludes that chronic OPs exposure induces oxidative stress which is associated with the related SNP polymorphism. The toxicogenetics of understudied SNPs were examined for the first time to our understanding. The findings may lead to a newer area of investigation on OPs induced health issues and toxicogenetics.
Subject(s)
Environmental Exposure/analysis , Gene-Environment Interaction , Organophosphorus Compounds/adverse effects , Oxidative Stress/genetics , Polymorphism, Single Nucleotide , Acetylcholinesterase/genetics , Adolescent , Adult , Butyrylcholinesterase/genetics , Cameroon , Catalase/genetics , Environmental Exposure/adverse effects , Female , GPI-Linked Proteins/genetics , Glutathione , Glutathione S-Transferase pi/genetics , Glutathione Transferase/genetics , Humans , Male , Malondialdehyde , Middle Aged , Pakistan , Sirtuin 1/genetics , Young AdultABSTRACT
Group A rotaviruses (RVA) are one of the major causes of acute gastroenteritis (AGE) in young children worldwide. Owing to lack of proper surveillance programs and health facilities, developing countries of Asia and Africa carry a disproportionately heavy share of the RVA disease burden. The aim of this hospital-based study was to investigate the circulation of RVA genotypes in Rawalpindi and Islamabad, Pakistan in 2015 and 2016, prior to the implementation of RVA vaccine. 639 faecal samples collected from children under 10 years of age hospitalized with AGE were tested for RVA antigen by ELISA. Among 171 ELISA positive samples, 143 were successfully screened for RT-PCR and sequencing. The prevalence of RVA was found to be 26.8% with the highest frequency (34.9%) found among children of age group 6-11 months. The most predominant circulating genotypes were G3P[8] (22.4%) followed by G12P[6] (20.3%), G2P[4] (12.6%), G1P[8] (11.9%), G9P[6] (11.9%), G3P[4] (9.1%), G1P[6] (4.2%), G9P[8] (4.2%), and G3P[6] (0.7%). A single mixed genotype G1G3P[8] was also detected. The findings of this study provide baseline data, that will help to assess if future vaccination campaigns using currently available RVA vaccine will reduce RVA disease burden and instigate evolutionary changes in the overall RVA biology. The high prevalence of RVA infections in Pakistan require to improve and strengthen the surveillance and monitoring system for RVA. This will provide useful information for health authorities in planning public health care strategies to mitigate the disease burden caused by RVA.
Subject(s)
Gastroenteritis/virology , Rotavirus Infections/epidemiology , Rotavirus/classification , Sequence Analysis, DNA/methods , Antigens, Viral/metabolism , Child , Child, Preschool , Feces/virology , Female , Gastroenteritis/immunology , Genotype , Humans , Infant , Infant, Newborn , Male , Pakistan/epidemiology , Phylogeny , Prevalence , Rotavirus/genetics , Rotavirus/immunology , Rotavirus Infections/immunology , Rotavirus Infections/virologyABSTRACT
OBJECTIVE: To examine the risk and preventive factors of working in a cement plant. METHODS: The cross-sectional study was conducted from July to September, 2016, at a leading cement manufacturing plant in the Khyber Pakhtunkhwa province of Pakistan. An interviewer-administered questionnaire was used to collect data about the characteristics of exposed and unexposed subjects. The characteristics and occupational illnesses were compared between exposed and unexposed workers. Logistic regression was applied to estimate the odds ratio for risk and preventive factors associated with pulmonary illnesses linked with the profession. RESULTS: Of the 550 workers contacted, 260(47.3%) agreed to participate. The mean age of the sample was 30.48}6.13 years. Of the total, 80(31%) were exposed and 180(69%) were unexposed. Overall, 96(37%) workers had medical coverage facility, while 114(63%) reported very good health. All socioeconomic and working characteristics were highly significant between exposed and unexposed workers (p<0.05). There were 67(25.7%) workers with pulmonary illnesses and the difference between the exposed and unexposed groups were significant (p<0.05). CONCLUSIONS: Pulmonary health among workers could be improved by implementing occupational health improving strategies..