Elucidating the Mechanism of Copper-Induced Photoluminescence Quenching in 2-Phenylbenzimidazole-5-Sulfonic Acid.

To explore the possible impact of 2-Phenylbenzimidazole-5-sulfonic acid (PBSA) on the function of a sunscreen, in this work we investigate the binding of copper metal ions (Cu2+) to PBSA. Due to the existence of an intrinsic interaction phenomenon between Cu2+ ions and PBSA molecules, the photoluminescence (PL) quenching arises owing to the charge transfer from PBSA to Cu2+ ions. The mechanism of fluorescence quenching is probed experimentally following excitation at 306 nm by evaluating various quenching parameters with the help of the Stern-Volmer plot. Through the assessment of the values of the Stern-Volmer constant ( K SV = 45.2 M - 1 ) and bimolecular quenching rate constant ( k q = 0.77 × 10 10 M - 1 . s - 1 ), it is deduced that the dynamic mode of PL quenching is operative between PBSA and Cu2+ ions. We evaluate the number of binding sites (n = 1) that advocate the presence of a single binding site in PBSA for Cu2+ ions. The numerical value of standard Gibbs free energy change, Δ G o ~ -27.485 kJ.mol-1 implies the spontaneous binding between Cu2+ ions and PBSA molecules. The results obtained give an insight into the mechanism of metal-induced PL quenching of water soluble PBSA sunscreen.

Protective and Flame-Retardant Bifunctional Epoxy-Based Nanocomposite Coating by Intercomponent Synergy between Modified CaAl-LDH and rGO.

Extensive utilization in various settings poses extra requirements of coatings beyond just anticorrosion properties. Herein, 8-hydroxyquinoline (8-HQ) intercalated CaAl-based layered double hydroxide (CaAl-8HQ-LDH) was loaded on reduced GO (rGO) through a one-pot hydrothermal reaction, which was employed as the nanofiller endowing the epoxy (EP/CaAl-8HQ LDH@rGO) with excellent flame-retardancy while ensuring efficient protection for mild steel. Results of electrochemical impedance spectroscopy (EIS) demonstrated the durability of the EP/CaAl-8HQ LDH@rGO-coated specimen, with the impedance at the lowest frequency (|Z|0.01Hz) maintained as 1.84 × 1010 Ω cm2 after 120 days of immersion in a 3.5 wt % NaCl solution. Even for the scratched EP/CaAl-8HQ LDH@rGO system, only a slight decline in |Z|0.01Hz was observed during 180 h of exposure to the NaCl solution, indicating a self-healing feature supported by salt spray tests. UL-94 burning tests revealed the V-0 rating for EP/CaAl-8HQ LDH@rGO with improved thermostability. Strong physical barrier from two-dimensional rGO and the release of 8-HQ from LDH interlayers accounted for the anticorrosive and self-healing properties. However, O2-concentration dilution and charring-layer promotion governed the flame-retardant behavior of the nanocomposite coating. The intercomponent synergy of nanofillers achieved in this work may provide a useful reference for designing multifunctional coatings.

Effect of surface ligands on the photoinduced electron transfer rate and efficiency in ZnO quantum dots and graphene oxide assemblies.

Apart from biocompatibility, ZnO quantum dots (QDs) are considered to be an efficient luminescence material due to their low cost and high redox potential. Here, we report the synthesis of ZnO QDs by using five different functionalizing ligands like mercaptoacetic acid (MAA), 3-mercaptopropionic acid (MPA), octadecene (ODE), ethylene glycol (EG), and oleyl amine (OLA) and fabricate their assemblies with graphene oxide (GO). We investigate the role of functionalizing ligands as a surface modifier of ZnO QDs for their attachment to GO. The steady-state photoluminescence (SSPL) and time-resolved photoluminescence (TRPL) analyses demonstrate the photoluminescence (PL) quenching of ZnO QDs in ZnO QDs-GO assembly. The highest reduction in PL intensity is observed with ZnO QDs-GO assembly with EG as a surface functionalizing ligand. Cyclic voltammetry (CV) analysis confirms the feasibility of charge transfer from ZnO QDs to the GO. The maximum (79.43%) charge transfer efficiency (ECT ) is observed in the case of ZnO-MAA-GO as compared to other assemblies. This means the thiol group-containing ligands facilitate charge transfer as compared to hydroxyl and amine group ligands. This leads to the conclusion that charge transfer in ZnO QDs-GO assemblies depends strongly on the nature of surface ligands.

Correlation of Fasting Blood Sugar and Glycated Hemoglobin (HbA1c) With Thiamine Levels in Diabetic Patients.

Introduction It has been discovered that low levels of thiamine reserves in the body are related to diabetes mellitus (DM) because thiamine directly influences carbohydrate metabolism. Therefore, the purpose of this study was to assess several metabolic variables and blood thiamine levels in patients with type 1 and type 2 DM and compare them with those in a control group of healthy individuals. Methods This case-control study was conducted at multiple diabetic outpatient centers in Karachi. A total of 90 participants, who were divided into three groups, each containing 30 individuals, were chosen using a convenient non-probability sampling technique. Group A served as the control group and consisted of healthy, non-diabetic individuals. Groups B and C contained subjects with type 1 and type 2 DM, respectively. Descriptive analysis was reported as mean standard deviation, whereas gender and comorbidities were expressed as frequencies and percentages. The chi-square test and Pearson's correlation coefficient were used to determine the associations of the variables with type 1 DM, type 2 DM, and controls. Results The study results revealed statistically significant differences between controls, type 1 and type 2 DM, in the means of blood glucose levels and all lipid profiles, such as glycated hemoglobin (HbA1c), fasting blood sugar (FBS), random blood sugar (RBS), serum thiamine, triglycerides (p < 0.001), high-density lipoprotein (HDL) (p = 0.014), and total cholesterol (p = 0.013). Furthermore, it was shown that among the control group, type 1 and type 2 DM, HbA1c, and FBS were insignificantly correlated with thiamine levels, whereas the HbA1c and FBS of the combined diabetic groups were significantly correlated with the thiamine level (r = 0.465, p < 0.001) and (r = 0.360, p = 0.005), respectively, where 'r' is the Pearson correlation coefficient. Additionally, HbA1c and FBS in the combined three groups were significantly correlated with the thiamine level (r = -0.626, p < 0.001) and (r = -0.561, p < 0.001), respectively. Conclusion This study concluded that patients with type 1 and type 2 DM had significantly higher levels of FBS, RBS, HbA1c, triglycerides, and total cholesterol than controls. Furthermore, both type 1 and type 2 DM patients' serum thiamine and HDL levels were observed to be considerably lower than those of controls. Additionally, among both types of DM and controls, there was a strong correlation between FBS and HbA1c. Therefore, we recommend that serum thiamine levels be routinely monitored in diabetic patients, and thiamine supplementation should be considered to avoid complications, especially vascular complications of DM.

Efficacy of cell-free DNA as a diagnostic biomarker in breast cancer patients.

Breast cancer is the most prevalent and leading cause of mortality worldwide among women. Cell-free DNA (cfDNA) analysis is an alternative quantitative approach to conventional methods for cancer diagnosis. The current research project aimed to determine the efficacy of cfDNA as a diagnostic biomarker in breast cancer patients in Pakistan. Eighty-four female breast cancer patients were selected as cases, and 152 healthy females as controls. Immunohistochemistry was performed to identify tumor biomarkers along with clinical profiling. cfDNA was extracted from serum using the phenol-chloroform method. The cfDNA level in the serum was estimated using Agarose Gel Electrophoresis and Nanodrop. SPPS version 25.0 was used to perform statistical analyses. The results showed that the cancer biomarkers were significantly associated with breast cancer. The changes in hematological parameters were insignificant, whereas the biochemical parameter variations between the cases and controls were statistically significant. A significant association of cfDNA level with breast cancer was observed. Further cfDNA levels and cancer biomarkers were not statistically significant. A significant correlation was observed between cfDNA and biochemical parameters, except for creatinine, whereas hematological parameters showed no significant correlation.ROC analysis declared cfDNA as an authentic diagnostic marker for breast cancer. It was concluded that the level of cfDNA is significantly increased in breast cancer patients and can be utilized as a diagnostic biomarker.

Neurological Features and Their Association With Gender in Diabetes Mellitus Patients.

Introduction Understanding the wide range of clinical signs and symptoms associated with diabetes mellitus (DM) is crucial because people with DM are frequently misdiagnosed, given incorrect care, or poorly controlled. Therefore, the purpose of this study was to evaluate the neurological symptoms associated with type 1 and type 2 DM patients with respect to patient gender. Methods This was a cross-sectional multicenter study that was conducted at different hospitals using a non-probability sampling method. The duration of the study was eight months, from January 2022 to August 2022. The study involved 525 type 1 and type 2 DM patients with an age range from 35 to 70 years. Demographic details such as age, gender, socioeconomic status, past medical history, presence of comorbidities, type, and duration of DM, and neurological features were recorded as frequencies and percentages. A Chi-square test was used to determine the association between neurological symptoms associated with type 1 and type 2 DM and gender. Results The study findings showed that of 525 diabetic patients, 210 (40.0%) were females and 315 (60.0%) were males. The mean male and female mean ages were 57.36±14.99 and 50.52±14.8 years, respectively, with a significant difference with respect to gender (p<0.001). The prevalence of neurological manifestations showed that irritability or mood swings were reported by most of the male 216 (68.6%) and 163 (77.6%) female diabetic patients, with a significant association noticed (p=0.022). Moreover, a significant association was observed between both genders in terms of swelling of feet, ankles, hands, and eyes (p=0.042), confusion or difficulty in concentration (p=0.040), burning pain in feet or legs (p=0.012), and muscular pain or cramps in legs or feet (p=0.016).  Conclusion This study concluded that the prevalence of neurological manifestations was high among diabetic patients. Most of the neurological symptoms were significantly more pronounced in female diabetic patients. Moreover, most of the neurological symptoms were associated with the type (type 2 DM) and duration of DM. The presence of hypertension, dyslipidemia, and smoking also influenced some neurological manifestations.

Sinovac COVID-19 Side Effects in Hypertensive Patients: An Observational Study From Pakistan.

Background The most important factor in combating the coronavirus disease 2019 (COVID-19) pandemic was the provision of safe and effective vaccines. The acceptance of vaccines is impacted by several variables, including beliefs about the vaccine's safety and adverse effects. Vaccine side effects can vary depending on the type, but they are often moderate, localized, transient, and self-limiting. Therefore, this study aimed to assess the prevalence of side effects experienced after receiving the Sinovac vaccine by participants hypertensive and non-hypertensive participants. Methodology This was a cross-sectional, multicenter study that was performed using non-probability sampling. The study duration was six months from May 1, 2022, to October 31, 2022. The study involved 600 individuals who had either received the first or second dose of the Sinovac vaccine. For categorical data, frequencies and percentages were documented. The chi-square test was applied to determine the association between local and systemic side effects among hypertensive and non-hypertensive participants. Results The study findings showed that out of 600 participants, there were 187 (62.3%) males and 113 (37.7%) females with hypertension, and 222 (74.0%) males and 78 (26.0%) females without hypertension, with a significant association (p = 0.002). Following the first dose of the Sinovac vaccine, fever was the most commonly reported side effect in 153 (51.0%) hypertensive participants and 62 (20.7%) non-hypertensive participants, with a significant association (p < 0.001). Similarly, following the second dose of the Sinovac vaccine, fever was the most commonly reported side effect in 108 (36.0%) hypertensive participants and 57 (19.0%) non-hypertensive participants, with a significant association (p < 0.001). Conclusions This study concluded that the presence of hypertension significantly increased the manifestations of local and systemic side effects compared with non-hypertensive participants. Moreover, fever, pain, and swelling at the injection site were the most commonly reported side effects after receiving the first and second doses of the Sinovac vaccine.

Quantifying irrigation water demand and supply gap using remote sensing and GIS in Multan, Pakistan.

Human interventions and rapid changes in land use adversely affect the adequate distribution of water resources. A research study was conducted to quantify the gap between demand and supply for irrigation water in Multan, Pakistan, which may lead to sustainable water management. Two remotely sensed images (Landsat 8 OLI and Landsat 5 TM) were downloaded for the years 2010 and 2020, and supervised classification method was performed for the selected land use land cover (LULC) classes and basic framework. During the evaluation, the kappa coefficient was found in the ranges of 0.83-0.85, and overall accuracy was found to be more than 80% which indicated a substantial agreement between the classified maps and the ground truth data for both years and seasons. The LULC maps showed that urbanization has increased by 49% during the last decade (2010-2020). Reduction in planting areas for wheat (9%), cotton (24%), and orchards (46%) was observed. An increase in planting areas for rice (92%) and sugarcane (63%) was observed. The changing LULC pattern may be related to variation in water demand and supply for irrigation. The irrigation water demand has decreased by 370.2 Mm3 from 2010 to 2020, due to the reduction in agricultural land and an increase in urbanization. Available irrigation water supply (canals/rainfall) was estimated as 2432 Mm3 for the year 2020 which was 26% less than that of total irrigation water demand (3281 Mm3). The findings also provide the database for sustainable water management and equitable distribution of water in the region.

The Common Systemic and Local Adverse Effects of the Sinovac COVID-19 Vaccine: An Observational Study From Pakistan.

Background Vaccination acts by boosting the capacity of a person's immune system to identify and effectively resist infection-causing bacteria and viruses, as it stimulates the immune system to respond to the vaccine's antigens. The immunological response may include local and systemic symptoms, including pain at the injection site and fever, respectively. The Sinovac vaccine is an inactivated virus vaccine made in China and is one of the most widely used vaccines in many countries; however, the side effects of the Sinovac vaccine have not been well-studied in our population. Therefore, this study assessed the prevalence of side effects experienced by participants after receiving the Sinovac vaccine. Methodology This multicenter, cross-sectional study was conducted using a non-probability sampling method. The duration of the study was six months from May 1, 2022, to October 31, 2022. A total of 800 participants who were completely vaccinated with the Sinovac vaccine were included in the study. For categorical data, frequencies and percentages were documented, while for continuous data, such as age, height, weight, and the duration of comorbidities, means and standard deviations were evaluated. Results The study findings showed that out of 800 participants, 534 (66.8%) were males and 266 (33.3%) were females, with a mean age of 41.20 ± 13.70 years. Among them, 162 (20.3%) had hypertension, and 104 (13.0%) had diabetes. Following the first dose of the Sinovac vaccine, fever was the most commonly reported side effect in 350 (43.8%) participants. Additionally, pain at the injection site in 238 (29.8%) participants, followed by swelling at the injection site in 228 (28.5%) recipients, were among other common side effects. Following the second dose of the Sinovac vaccine, fever was the most commonly reported side effect in 262 (32.8%) participants. Conclusions This study concluded that fever was the most frequent systemic side effect, whereas pain and swelling at the injection site were the most frequent local side effects following the administration of the first and second doses of the Sinovac vaccine. Both dosages of Sinovac were well-tolerated, and the majority of the adverse effects were minor and self-limiting.

Probing the Förster Resonance Energy Transfer Dynamics in Colloidal Donor-Acceptor Quantum Dots Assemblies.

In this article, we report the synthesis of graphene quantum dots (GQDs) by hydrothermal method and surface modified CdS quantum dots (QDs) via the colloidal method and the fabrication of their dyad. The CdS QDs functionalized by mercaptoacetic acid (MAA) attach to the GQDs via electrostatic interactions. Spectral overlapping between the emission spectrum of GQDs and the absorption spectrum of CdS QDs allows efficient Förster resonance energy transfer (FRET) from GQDs to the CdS QDs in the GQDs-CdS QDs dyads. The magnitude of FRET efficiency (E) and the rate of energy transfer (kE) assessed by the photoluminescence (PL) decay kinetics are ~61.84% and ⁓3.8 × 108 s- 1, respectively. These high values of FRET efficiency and energy transfer rate can be assigned to the existence of strong electrostatic interactions between GQDs and CdS QDs, which arise due to the presence of polar functionalities on the surface of both GQDs and CdS QDs. The understanding of energy transfer in the luminescent donor-acceptor FRET system is of significant importance and the practical implications of such FRET systems could overall improve the efficiency of photovoltaics, sensing, imaging and optoelectronic devices.

Enhancing the FRET by tuning the bandgap of acceptor ternary ZnCdS quantum dots.

In this article, we report the band gap tuning of ternary ZnCdS quantum dots (QDs) by varying the concentration of the capping ligand, mercaptoacetic acid (MAA). The functionalization of QDs leads to the control of their size and band gap due to the quantum confinement effect, causing blue shift in the absorption and photoluminescence (PL) spectra with a gradual change in the concentration of the capping ligand from 0.5 to 2.5 M. Ensulizole (2-phenylbenzimidazole-5-sulfonic acid) is an important organic ultraviolet (UV) filter that is frequently used in sunscreen cosmetics. An effective overlapping of the PL spectrum of ensulizole and the absorption spectrum of QDs with 2.5 M MAA is achieved. A formidable decrease in the PL intensity and the PL lifetime of ensulizole promotes an efficient Förster resonance energy transfer (FRET) from sunscreen ensulizole to the QDs. The magnitude of the FRET efficiency (E) is ∼70%. This very high value of E is the signature of the existence of a very fast energy transfer process from ensulizole to the MAA functionalized ZnCdS QDs. The dyad system consisting of ZnCdS QDs and ensulizole sunscreen can serve as a prototype model to develop a better understanding of the photochemistry of ensulizole and consequently the formulation of more efficient sunscreen cosmetics.

Tuning charge transfer efficiency by functionalizing ligands in FAPbBr3 nanocrystals and graphene heterostructures.

The combination of halide perovskite NCs with graphene to design heterostructures has proven to be a promising candidate for energy applications, optoelectronics, and photocatalysis. Efficient light energy absorption in perovskite NC-graphene heterostructures is of fundamental importance owing to their optoelectronic applications. A detailed understanding of the important process for device action, particularly interfacial charge transfer (CT), has thus far lingered subtly. This study describes the influence of the different surface functionalities of graphene on the CT dynamics in FAPbBr3 NCs attached to functionalized graphene heterostructures. Functionalized graphenes i.e., graphene oxide (GO) and amino acids (alanine (Ala), tyrosine (Tyr) and cysteine (Cys)) functionalized GO, were synthesized. By assembling the heterostructures of functionalized graphene with NCs, the quenching of photoluminescence (PL) of the FAPbBr3 NCs was observed. The photo-generated hole transfer from FAPbBr3 to functionalized graphene is responsible for PL quenching, which is supported by time-resolved photoluminescence (TRPL) and cyclic voltammetry (CV) analysis. Our study revealed that the rate of CT and charge transfer efficiency (ECT) strongly depend on the nature of the functionalizing moieties. The highest hole transfer efficiency for NC-functionalized graphene heterostructures was observed in the case of cysteine-functionalized GO (88.84%) and the lowest with GO (38.15%). This suggests that cysteine-functionalized graphene is the best hole acceptor amongst all functionalized graphenes. This study offers a method to regulate energetics and investigate the extent of hole transfer in perovskite NCs and functionalized graphene heterostructures. These findings tend to draw new directions to stimulate advance research regarding the fundamental understanding of hole transfer in surface-modified donor-acceptor heterostructures for light harvesting assemblies, especially solar cells.

Green buildings model: Impact of rigid polyurethane foam on indoor environment and sustainable development in energy sector.

The construction and building industry in the modern world heavily relies on advanced techniques and materials such as polymers. However, with the world's population alarmingly increasing, contributing to the greenhouse effect, and severe weather conditions amplifying, it has become crucial to reduce the heat effects in both new and old buildings. To achieve this, 50-70% more energy is necessary, which highlights the importance of energy-efficient construction practices and materials. Consequently, a comprehensive study was conducted to evaluate the efficacy of Polyurethane in indoor environments and energy conservation. Current study was performed due to an innovative application of insulation materials as to reduce the heat and energy costs in construction works. Thermal conductivity at mean temperature 35 °C was found 0.0272 (W/m K) with maximum in burnt clay brick (1.43 W/m K) by using hotplate apparatus. Specific heat was also found less 0.85 (KJ/Kg K) at density 32 kg/m3 while results were at par in reinforcement cement concrete and burnt clay brick 0.91, 0.91 (KJ/Kg K) respectively. Similarly, heat transmittance values of different roof sections by using polyurethane insulation showing satisfaction the ECBC in Buildings deviating standard U-value 1.20% to 0.418 (W/m2 K) with its excellent performance. Polyurethane treatments have been found to exert a significant impact on the computation of thermal resistance and overall heat transfer coefficients. In contrast, non-insulated treatments yielded inconclusive results with little to no significance. This highlights the importance of insulation materials in energy-efficient construction practices. Energy consumption in winter and summer also has shown the significant impact by using polyurethane application with cumulative saving of 60-62% electricity. Economic Benefit of polyurethane in RCC and Conventional buildings describes positive and highly significant impact in present study. Application of polyurethane in new and old buildings ultimate enhanced the better quality of life and living standards from people of applied countries and is strongly recommended for future prospects and endeavors as Eco-friendly and energy efficient for sustainable development.

Impacts of COVID-19 pandemic on environment, society, and food security.

Coronavirus disease (COVID)-19 is a viral and transferable disease caused by severe respiratory syndrome-coronavirus-2. It can spread through breathing droplets in human beings. It caused 5.32 million deaths around the world at the end of 2021. COVID-19 has caused several positive impacts as well, such as a reduction in air, water, and noise pollution. However, its negative impacts are by far critical such as increased death rate, increased release of microcontaminants (pesticides, biocides, pharmaceuticals, surfactants, polycyclic aromatic hydrocarbons (PAHs), flame retardants, and heavy metals), increased biomedical waste generation due to excessive use of safety equipment and its disposal, and municipal solid waste generation. Environmental pollution was significantly reduced due to lockdown during the COVID-19 period. Therefore, the quality of air and water improved. COVID-19 affected all sections of the population, particularly the most vulnerable members of society, and thus pushed more people into poverty. At the world level, it increased risks to food safety by increasing prices and lowering revenues, forcing households to reduce their food consumption in terms of quantity and quality. COVID-19 also upset various exercises e.g., horticulture, fisheries, domesticated animals, and agribusiness hence prohibiting the development of merchandise for poor-country ranchers. Most of the patients can self-recover from COVID-19 if they do not have any other diseases like high blood pressure, diabetes, and heart problems. Predictably, the appropriate execution of the proposed approaches (vaccination, wearing face masks, social distancing, sustainable industrialization) is helpful for worldwide environmental sustainability.

Understanding the dynamics of capital structure, corporate governance, and corporate social responsibility in high- and low-leveraged US and Chinese firms.

Corporate social responsibility turned into a global sensation from the inception of the twenty-first century in the corporate world and grabbed immense engrossment from all stakeholders in their decision-making process. Capital structure and corporate governance practices are the well-mellowed facets of corporate finance literature. In this study, the moderating role of corporate social responsibility (CSR) between corporate governance and leverage of the US and Chinese listed firms has been established, with a further extension of analyzing the moderating role of CSR between corporate governance and leverage in high vs low leveraged firms and high CSR vs low CSR firms as the novelty of this study and has never been examined in both economies and globally. The data of 1989 Chinese-listed firms from 28 sectors of the economy and 6640 US-listed firms from 27 sectors of the economy has been taken from 2001 to 2019 and analyzed through fixed effect regression and system generalized method of moment (GMM). Results of the study reveal that CSR and corporate governance are negatively associated with the leverage of both Chinese and US firms. Moreover, the moderating role of CSR has established between corporate governance and leverage negative relationship. The moderating role of CSR in the relationship of leverage and corporate governance is established only in low-leveraged firms whereas it is insignificant in high-leveraged firms. System GMM confirms the signs and significance of the regression results; that is why regression results are robust and reliable, and there is no endogeneity problem in our model. The study also gives an insight for future research on high- and low-leveraged firms and firms with more CSR score than less CSR score with other dimensions such as firm performance and firm value variables.

Assessment of land use/land cover changes and its effect on land surface temperature using remote sensing techniques in Southern Punjab, Pakistan.

Land surface temperature (LST) is defined as a phenomenon which shows that microclimate of an urban system gets heated much faster than its surrounding rural climates. The expansion of buildings has a noteworthy influence on land use/land cover (LULC) due to conversion of vegetation land into commercial and residential areas and their associated infrastructure by which LST is accelerated. The objective of the research was to study the impact of changes in LULC on LST of Southern Punjab (Pakistan) through remote sensing (RS) data. Landsat images of 30-year duration (1987, 1997, 2007 and 2017) were employed for identifying vegetation indices and LST in the study region. These images also helped to work out normalized difference water index (NDWI) and normalized difference built-up index (NDBI) maps. There was an increase from 29620 (3.63 %) to 88038 ha (10.8 %) in built-up area over the 30 years. LST values were found in the range 12-42 °C, 11-44 °C, 11-45 °C and 11-47 °C in the years 1987, 1997, 2007 and 2017, respectively. Regression coefficients (R2) 0.81, 0.78, 0.84 and 0.76 were observed between NDVI and LST in the corresponding years respectively. Our study showed that NDVI and NDWI were negatively correlated with less LST; however, NDBI showed positive correlation with high LST. Our study gives critical information of LULC and LST and will be a helpful tool for policy makers for developing effective policies in managing land resources.

Using space-time scan statistic for studying the effects of COVID-19 in Punjab, Pakistan: a guideline for policy measures in regional agriculture.

Pakistan is included in top 50 countries which are estimated to face serious agriculture and food deficiency related challenges due to the worldwide pandemic coronavirus 2019 (COVID-19). The aim of this study was to evaluate the effects of COVID-19 on food supply chain and agriculture in Punjab, Pakistan, by using space-time scan statistic (STSS). A survey was conducted at 720 points in different districts of the province. The STSS detected "active" and emerging clusters that are current at the end of our study area-particularly, 17 clusters were formed while adding the updated case data. Software ArcGIS 10.3 was used to find relative risk (RR) values; the maximum RR value was found to be 42.19 and maximum observed cases 53,265 during June 15-July 1, 2020. It was not always necessary that if the number of active cases in Punjab increased, there should be higher relative risk for more number of districts and vice versa. Due to the highest number of cases of COVID-19 and RR values during July, mostly farmers faced many difficulties during the cultivation of cotton and rice. Mostly farmers (72%) observed increase in prices of inputs (fertilizers and pesticides) during lockdown. If the supply chain of agriculture related inputs is disturbed, farmers may find it quite difficult to access markets, which could result in a decline in production and sales of crops and livestock in study area. It is suggested that to protect the food security and to decrease the effect of the lockdown, Punjab government needs to review food policy and analyse how market forces will respond to the imbalanced storage facilities and capacity, supply and demand and price control of products. The findings of this study can also help policy-makers to formulate an effective food security and agriculture adaptation strategy.

Cu-Enhanced Efficient Förster Resonance Energy Transfer in PBSA Sunscreen-Associated Ternary Cu x Cd1-x S Quantum Dots.

Quantum dots (QDs) are semiconducting nanocrystals that exhibit size- and composition-dependent optical and electronic properties. Recently, Cu-based II-VI ternary Cu x Cd1-x S (CCS) QDs have emerged as a promising class of QDs as compared to their binary counterparts (CuS and CdS). Herein, a series of ternary CCS QDs are synthesized by changing the molar concentration of Cu2+ ions only keeping the 1:1 ratio of the stoichiometric mixture of Cd2+ and S2-. These CCS QDs are attached to 2-phenylbenzimidazole-5-sulfonic acid (PBSA), an eminent UV-B filter widely used in many commercial sunscreen products to avoid skin erythema and DNA mutagenic photolesions. The photoinduced Förster resonance energy transfer (FRET) is investigated from PBSA to CCS QDs as a function of Cu concentration in CCS QDs using the steady-state photoluminescence and time-resolved photoluminescence measurements. A 2-fold increase in the magnitude of non-radiative energy transfer rate (K T(r)) is observed as the molar concentration of Cu in CCS QDs increases from 2 to 10 mM. Our findings suggest that in PBSA-CCS QD dyads, the FRET occurrence from PBSA to QDs is dictated by the dynamic mode of photoluminescence (PL) quenching. The bimolecular PL quenching rate constants (k q) estimated by Stern-Volmer's plots for PBSA-CCS QD dyads are of the order of 1010 M-1 s-1, which signifies that in the PBSA-CCS QD dyad FRET system, the process of PL quenching is entirely diffusion-controlled.