A systematic first-principles investigation of the structural, electronic, mechanical, optical, and thermodynamic properties of Half-Heusler ANiX (ASc, Ti, Y, Zr, Hf; XBi, Sn) for spintronics and optoelectronics applications.

This paper is the first to look at the structural, electronic, mechanical, optical, and thermodynamic properties of the ANiX (ASc, Ti, Y, Zr, Hf; XBi, Sn) half-Heusler (HH) using DFT based first principles method. The lattice parameters that we have calculated are very similar to those obtained in prior investigations with theoretical and experimental data. The positive phonon dispersion curve confirm the dynamical stability of ANiX (ASc, Ti, Y, Zr, Hf; XBi, Sn). The electronic band structure and DOS confirmed that the studied materials ANiX (ASc, Ti, Y, Zr, Hf; XBi, Sn) are direct band gap semiconductors. The investigation also determined significant constants, including dielectric function, absorption, conductivity, reflectivity, refractive index, and loss function. These optical observations unveiled our compounds potential utilization in various electronic and optoelectronic device applications. The elastic constants were used to fulfill the Born criteria, confirming the mechanical stability and ductility of the solids ANiX (ASc, Ti, Y, Zr, Hf; XBi, Sn). The calculated elastic modulus revealed that our studied compounds are elastically anisotropic. Moreover, ANiX (ASc, Ti, Y, Zr, Hf; XBi, Sn) has a very low minimum thermal conductivity (Kmin), and a low Debye temperature (θD), which indicating their appropriateness for utilization in thermal barrier coating (TBC) applications. The Helmholtz free energy (F), internal energy (E), entropy (S), and specific heat capacity (Cv) are determined by calculations derived from the phonon density of states.

Point-of-use chlorine residuals and disinfection byproduct occurrences in rural households served by public water utilities in Appalachian Virginia.

We characterized concentrations of trihalomethanes (THMs), a measure of disinfection byproducts (DBPs), in tap water samples collected from households with utility-supplied water in two rural counties in Appalachian Virginia, and assessed associations with pH, free chlorine, and metal ions which can impact THM formation. Free chlorine concentrations in all samples (n = 27 homes) complied with EPA drinking water guidelines, though 7% (n = 2) of first draw samples and 11% (n = 3) of 5-min flushed-tap water samples exceeded the US Safe Drinking Water Act (SDWA) maximum contaminant level (MCL) for THM (80 ppb). Regression analyses showed that free chlorine and pH were positively associated with the formation of THM levels above SDWA MCLs (OR = 1.04, p = 0.97 and OR = 1.74, p = 0.79, respectively), while temperature was negatively associated (OR = 0.78, p = 0.38). Of the eight utilities serving study households, samples from water served by three different utilities exceeded the EPA MCL for THM. Overall, these findings do not indicate substantial exposures to DBPs for rural households with utility-supplied water in this region of southwest Virginia. However, given the observed variability in THM concentrations between and across utilities, and established adverse health impacts associated with chronic and acute DBP exposure, more research on DBPs in rural Central Appalachia is warranted.

Drinking water sources, quality, and associated health outcomes in Appalachian Virginia: A risk characterization study in two counties.

OBJECTIVES: In the US, violations of drinking water regulations are highest in lower-income rural areas overall, and particularly in Central Appalachia. However, data on drinking water use, quality, and associated health outcomes in rural Appalachia are limited. We sought to assess public and private drinking water sources and associated risk factors for waterborne pathogen exposures for individuals living in rural regions of Appalachian Virginia. METHODS: We administered surveys and collected tap water, bottled water, and saliva samples in lower-income households in two adjacent rural counties in southwest Virginia (bordering Kentucky and Tennessee). Water samples were tested for pH, temperature, conductivity, total coliforms, E. coli, free chlorine, nitrate, fluoride, heavy metals, and specific pathogen targets. Saliva samples were analyzed for antibody responses to potentially waterborne infections. We also shared water analysis results with households. RESULTS: We enrolled 33 households (83 individuals), 82% (n = 27) with utility-supplied water and 18% with private wells (n = 3) or springs (n = 3). 58% (n = 19) reported household incomes of <$20,000/year. Total coliforms were detected in water samples from 33% (n = 11) of homes, E. coli in 12%, all with wells or springs (n = 4), and Aeromonas, Campylobacter, and Enterobacter in 9%, all spring water (n = 3). Diarrhea was reported for 10% of individuals (n = 8), but was not associated with E. coli detection. 34% (n = 15) of saliva samples had detectable antibody responses for Cryptosporidium spp., C. jejuni, and Hepatitis E. After controlling for covariates and clustering, individuals in households with septic systems and straight pipes had significantly higher likelihoods of antibody detection (risk ratios = 3.28, 95%CI = 1.01-10.65). CONCLUSIONS: To our knowledge, this is the first study to collect and analyze drinking water samples, saliva samples, and reported health outcome data from low-income households in Central Appalachia. Our findings indicate that utility-supplied water in this region was generally safe, and individuals in low-income households without utility-supplied water or sewerage have higher exposures to waterborne pathogens.

A novel investigation of pressure-induced semiconducting to metallic transition of lead free novel Ba3SbI3 perovskite with exceptional optoelectronic properties.

The structural, electronic, mechanical, and optical characteristics of barium-based halide perovskite Ba3SbI3 under the influence of pressures ranging from 0 to 10 GPa have been analyzed using first-principles calculations for the first time. The new perovskite Ba3SbI3 material was shown to be a direct band gap semiconductor at 0 GPa, but the band gap diminished when the applied pressure increased from 0 to 10 GPa. So the Ba3SbI3 material undergoes a transition from semiconductor to metallic due to high pressure at 10 GPa. The Ba3SbI3 material also exhibits an increase in optical absorption and conductivity with applied pressure due to the change in band gap, which is more suitable for solar absorbers, surgical instruments, and optoelectronic devices. The charge density maps confirm the presence of both ionic and covalent bonding characteristics. Exploration into the mechanical characteristics indicates that the Ba3SbI3 perovskite is mechanically stable. Additionally, the Ba3SbI3 compound becomes strongly anisotropic at high pressure. The insightful results of our simulations will all be helpful for the experimental structure of a new effective Ba3SbI3-based inorganic perovskite solar cell in the near future.

Spatial distribution of heavy metal abundance at distance gradients of roadside agricultural soil from the busiest highway in Bangladesh: A multi-index integration approach.

Bangladesh is currently experiencing significant infrastructural development in road networking system through the construction or reconstruction of multiple roads and highways. Consequently, there is a rise in traffic intensity on roads and highways, along with a significant contamination of adjacent agricultural soils with heavy metals. The purpose of this study was to evaluate the ecological risk, health risk and the abundance of seven heavy metals (Cu, Mn, Pb, Cd, Cr, As, and Ni) in three distance gradients (0, 300, and 500 m) of agricultural soil along the Dhaka-Chattogram highway. The concentration of heavy metals was measured with an Atomic Absorption Spectrophotometer (AAS) on a total of 36 soil samples that were taken from 12 different sampling sites. Based on the findings, Cd had a high contamination factor for all distance gradients, whereas Cr had a moderate contamination factor in 67% of the study areas. According to the Pollution Load Index (PLI), Cd, Cr, and Pb were the predominant pollutants. Principal component analysis (PCA) result shows these metals mainly came from anthropogenic sources. The considerable positive correlations between Cu-Pb, Cu-Cd, Pb-Cd, and Cr-Ni all pointed to shared anthropogenic origins. As per Potential Ecological Risk Assessment (PERI) analysis, Pb, Cd, Cr, and Ni each contribute significantly and pose a moderate threat. The Target Hazard Quotient (THQ) values for all pathways of exposure to Pb and Cr in soils were more than 1, which would pose a significant risk to human health in the following order: THQadult female > THQadult male > THQchildren. This study will help to evaluate the human health risk and develop a better understanding of the heavy metal abundance scenario in the agricultural fields adjacent to this highway.

Assessment of marketing mix associated with consumer's purchase intention of dairy products in Bangladesh: Application of an extended theory of planned behavior.

Despite persistent challenges, Bangladesh's dairy sector has been noticeable for a few decades. Although agriculture is the major contributor to GDP, dairy farming may play a crucial role in the economy by creating jobs, ensuring food security, and boosting the protein content of people's diets. This research aims to identify the direct and indirect factors influencing dairy product purchase intention amongst Bangladeshi consumers. Data were collected online using Google forms, and the convenience sampling technique was used to reach the consumers. The total sample size was 310. The collected data were analyzed using descriptive and multivariate techniques. Structural Equation Modeling results reveal that marketing mix and attitude are statistically significant with the intention to purchase dairy products. Also, the marketing mix influences the consumers' attitudes, subjective norms, and perceived behavioral control. However, there is no significant association between perceived behavioral control and subjective norm on intention to purchase. The findings suggest developing better products, ensuring reasonable pricing, performing promotional strategies, and proper placement to attract and increase consumers' intention to purchase dairy products.

Microbiological and chemical drinking water contaminants and associated health outcomes in rural Appalachia, USA: A systematic review and meta-analysis.

In rural areas of the United States, an estimated ~1.8 million people lack reliable access to safe drinking water. Considering the relative dearth of information on water contamination and health outcomes in Appalachia, we conducted a systematic review of studies of microbiological and chemical drinking water contamination and associated health outcomes in rural Appalachia. We pre-registered our protocols, limiting eligibility to primary data studies published from 2000 to 2019, and searched four databases (PubMed, EMBASE, Web of Science, and the Cochrane Library). We used qualitative syntheses, meta-analyses, risk of bias analysis, and meta-regression to assess reported findings, with reference to US EPA drinking water standards. Of the 3452 records identified for screening, 85 met our eligibility criteria. 93 % of eligible studies (n = 79) used cross-sectional designs. Most studies were conducted in Northern (32 %, n = 27) and North Central (24 %, n = 20) Appalachia, and only 6 % (n = 5) were conducted exclusively in Central Appalachia. Across studies, E. coli were detected in 10.6 % of samples (sample-size-weighted mean percentage from 4671 samples, 14 publications). Among chemical contaminants, sample-size-weighted mean concentrations for arsenic were 0.010 mg/L (n = 21,262 samples, 6 publications), and 0.009 mg/L for lead (n = 23,259, 5 publications). 32 % (n = 27) of studies assessed health outcomes, but only 4.7 % (n = 4) used case-control or cohort designs (all others were cross-sectional). The most commonly reported outcomes were detection of PFAS in blood serum (n = 13), gastrointestinal illness (n = 5), and cardiovascular-related outcomes (n = 4). Of the 27 studies that assessed health outcomes, 62.9 % (n = 17) appeared to be associated with water contamination events that had received national media attention. Overall, based on the number and quality of eligible studies identified, we could not reach clear conclusions about the state of water quality, or its impacts on health, in any of Appalachia's subregions. More epidemiologic research is needed to understand contaminated water sources, exposures, and potentially associated health outcomes in Appalachia.

Perovskite-structure TlBO3 (B = Cr, Mn) for thermomechanical and optoelectronic applications: an investigation via a DFT scheme.

First-principles-based DFT calculations have been carried out to analyze the structural, mechanical, elastic anisotropic, Vickers hardness, electronic, optical, and thermodynamic properties of TlBO3 (B = Cr, Mn) for the first time. We determined the lattice parameters, which are in good agreement with the previous results. The Born criteria was ensured by the elastic constants, which also confirms the ductility of the solid. The elastic constants were also used to evaluate and analyze some related physical properties. The values of Vickers hardness were calculated to determine the hardness and relative application of both TlCrO3 and TlMnO3. Though the metallic characteristics were evaluated via the investigation of the electronic band structure and density of states, both TlCrO3 and TlMnO3 reveal semiconducting behavior under spin-orbit polarization with up-spin and down-spin configurations. Significant constants such as absorption, conductivity, reflectivity, dielectric, loss function, and refractive index were also considered and determined without spin and with spin. As a result, various possible electronic, optical, and optoelectronic applications were predicted. TlBO3 (B = Cr, Mn) was also found to be reliable for thermal barrier coating (TBC) as indicated by the evaluated values of thermal conductivity and Debye temperature.

Bottled and Well Water Quality in a Small Central Appalachian Community: Household-Level Analysis of Enteric Pathogens, Inorganic Chemicals, and Health Outcomes in Rural Southwest Virginia.

Consumption of unsafe drinking water is associated with a substantial burden of disease globally. In the US, ~1.8 million people in rural areas lack reliable access to safe drinking water. Our objective was to characterize and assess household-level water sources, water quality, and associated health outcomes in Central Appalachia. We collected survey data and water samples (tap, source, and bottled water) from consenting households in a small rural community without utility-supplied water in southwest Virginia. Water samples were analyzed for physicochemical parameters, total coliforms, E. coli, nitrate, sulfate, metals (e.g., arsenic, cadmium, lead), and 30+ enteric pathogens. Among the 69% (n = 9) of households that participated, all had piped well water, though 67% (n = 6) used bottled water as their primary drinking water source. Total coliforms were detected in water samples from 44.4% (n = 4) of homes, E. coli in one home, and enteric pathogens (Aeromonas, Campylobacter, Enterobacter) in 33% (n = 3) of homes. Tap water samples from 11% (n = 1) of homes exceeded the EPA MCL for nitrate, and 33% (n = 3) exceeded the EPA SMCL for iron. Among the 19 individuals residing in study households, reported diarrhea was 25% more likely in homes with measured E. coli and/or specific pathogens (risk ratio = 1.25, cluster-robust standard error = 1.64, p = 0.865). Although our sample size was small, our findings suggest that a considerable number of lower-income residents without utility-supplied water in rural areas of southwest Virginia may be exposed to microbiological and/or chemical contaminants in their water, and many, if not most, rely on bottled water as their primary source of drinking water.

Global and local mutations in Bangladeshi SARS-CoV-2 genomes.

Coronavirus Disease 2019 (COVID-19) warrants comprehensive investigations of publicly available Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) genomes to gain new insight about their epidemiology, mutations, and pathogenesis. Nearly 0.4 million mutations have been identified so far among the ∼60,000 SARS-CoV-2 genomic sequences. In this study, we compared a total of 371 SARS-CoV-2 published whole genomes reported from different parts of Bangladesh with 467 sequences reported globally to understand the origin of viruses, possible patterns of mutations, and availability of unique mutations. Phylogenetic analyses indicated that SARS-CoV-2 viruses might have transmitted through infected travelers from European countries, and the GR clade was found as predominant in Bangladesh. Our analyses revealed 4604 mutations at the RNA level including 2862 missense mutations, 1192 synonymous mutations, 25 insertions and deletions and 525 other types of mutation. In line with the global trend, D614G mutation in spike glycoprotein was predominantly high (98 %) in Bangladeshi isolates. Interestingly, we found the average number of mutations in ORF1ab, S, ORF3a, M, and N were significantly higher (p < 0.001) for sequences containing the G614 variant compared to those having D614. Previously reported frequent mutations, such as R203K, D614G, G204R, P4715L and I300F at protein levels were also prevalent in Bangladeshi isolates. Additionally, 34 unique amino acid changes were revealed and categorized as originating from different cities. These analyses may increase our understanding of variations in SARS-CoV-2 virus genomes, circulating in Bangladesh and elsewhere.

Exploring the genomic and proteomic variations of SARS-CoV-2 spike glycoprotein: A computational biology approach.

The newly identified SARS-CoV-2 has now been reported from around 185 countries with more than a million confirmed human cases including more than 120,000 deaths. The genomes of SARS-COV-2 strains isolated from different parts of the world are now available and the unique features of constituent genes and proteins need to be explored to understand the biology of the virus. Spike glycoprotein is one of the major targets to be explored because of its role during the entry of coronaviruses into host cells. We analyzed 320 whole-genome sequences and 320 spike protein sequences of SARS-CoV-2 using multiple sequence alignment. In this study, 483 unique variations have been identified among the genomes of SARS-CoV-2 including 25 nonsynonymous mutations and one deletion in the spike (S) protein. Among the 26 variations detected in S, 12 variations were located at the N-terminal domain (NTD) and 6 variations at the receptor-binding domain (RBD) which might alter the interaction of S protein with the host receptor angiotensin-converting enzyme 2 (ACE2). Besides, 22 amino acid insertions were identified in the spike protein of SARS-CoV-2 in comparison with that of SARS-CoV. Phylogenetic analyses of spike protein revealed that Bat coronavirus have a close evolutionary relationship with circulating SARS-CoV-2. The genetic variation analysis data presented in this study can help a better understanding of SARS-CoV-2 pathogenesis. Based on results reported herein, potential inhibitors against S protein can be designed by considering these variations and their impact on protein structure.

Required water temperature in hotel plumbing to control Legionella growth.

Legionella spp. occurring in hotel hot water systems, in particular Legionella pneumophila, are causing serious pneumonic infections, and water temperature is a key factor to control their occurrence in plumbing systems. We performed a systematic review and meta-analyses of the available evidence on the association between water temperature and Legionella colonization to identify the water temperature in hotel hot water systems required for control of Legionella. Qualitative synthesis and quantitative analysis were performed on 13 studies that met our inclusion criteria to identify the effect of temperature. The Receiver Operating Characteristic (ROC) curve identified 55 °C as a cutoff point for hotel hot water temperature with an Area Under the Curve (AUC) value of 0.914. The odds ratios (OR) for detecting Legionella at temperatures >55 °C compared to lower temperatures from a meta-analysis of three studies was 0.17 [95% CI: 0.11, 0.25], which indicates a strong negative association between temperature and Legionella colonization. A logistic regression on results from multiple studies using both molecular and culture methods found a temperature of 59 °C associated with an 8% probability of detectable Legionella. Only two studies reported sufficiently detailed data to allow a model of concentration vs. temperature to be fit, and this model was not statistically significant. Additional research or more detailed reporting of existing datasets is required to assess if Legionella growth can be limited below particular concentration targets at different temperatures.

Temporal dynamics of land use/land cover change and its prediction using CA-ANN model for southwestern coastal Bangladesh.

Change analysis of land use and land cover (LULC) is a technique to study the environmental degradation and to control the unplanned development. Analysis of the past changing trend of LULC along with modeling future LULC provides a combined opportunity to evaluate and guide the present and future land use policy. The southwest coastal region of Bangladesh, especially Assasuni Upazila of Satkhira District, is the most vulnerable to natural disasters and has faced notable changes in its LULC due to the combined effects of natural and anthropogenic causes. The objectives of this study are to illustrate the temporal dynamics of LULC change in Assasuni Upazila over the last 27 years (i.e., between 1989 and 2015) and also to predict future land use change using CA-ANN (cellular automata and artificial neural network) model for the year 2028. Temporal dynamics of LULC change was analyzed, employing supervised classification of multi-temporal Landsat images. Then, prediction of future LULC was carried out by CA-ANN model using MOLUSCE plugin of QGIS. The analysis of LULC change revealed that the LULC of Assasuni had changed notably during 1989 to 2015. "Bare lands" decreased by 21% being occupied by other land uses, especially by "shrimp farms." Shrimp farm area increased by 25.9% during this period, indicating a major occupational transformation from agriculture to shrimp aquaculture in the study area during the period under study. Reduction in "settlement" area revealed the trend of migration from the Upazila. The predicted LULC for the year 2028 showed that reduction in bare land area would continue and 1595.97 ha bare land would transform into shrimp farm during 2015 to 2028. Also, the impacts of the changing LULC on the livelihood of local people and migration status of the Upazila were analyzed from the data collected through focus group discussions and questionnaire surveys. The analysis revealed that the changing LULC and the occupational shift from paddy cultivation to shrimp farming were related to each other. Around 31.3% of the total respondents stated that at least one of their family members had migrated. Climate-driven southwestern coastal people usually migrate from the vulnerable rural areas towards the nearest relatively safe city due to adverse effects of natural disasters. To control the unplanned development and reduce the internal migration in Assasuni and other coastal areas, a comprehensive land use management plan was suggested that would accommodate the diversified uses of coastal lands and eventually lessen the threats to the life and livelihood of the local people.

Rapid identification of enterovirulent Escherichia coli strains using polymerase chain reaction from shrimp farms.

Although, Escherichia coli is widely distributed in the environment, only a small percentage is pathogenic to humans. The most commonly encountered are those belonging to the Enterotoxigenic (ETEC), Enteroinvasive (EIEC), Enterohaemorrhagic (EHEC) and Enteropathogenic (EPEC) subtypes. Aquaculture premises specially shrimp farm in tropical and subtropical countries largely susceptive to different types of E. coli strains. With the PCR system, an attempt was taken to identify the virulent E. coli in a rapid basis from water, sediment and live shrimp from different shrimp farms established in the shrimp production areas of southwest part of Bangladesh. The target genes chosen for this investigation included the PhoA, a housekeeping gene in all E. coli and thereafter the virulent genes LT1, LT1 and ST1 of ETEC, the VT of EHEC and EAE of EPEC, which were amplified with the primers designed for their specific genes. The restriction enzyme conformation and the gel electrophoresis bands showed the presence of E. coli, among which ETEC and EPEC groups were present in the environmental and biological samples of shrimp farms, brings up into the human health concern. The sanitation conditions amid farm were also investigated to find the link of pathogenic E. coli, which came into the result of less infection if the farm maintains improved sanitation. This study has clearly urged the exigency of periodical quick check of virulent E. coli with the versatile PCR system from brood management to post-harvest handling of shrimp.