512 research outputs found

    ZnSe Nanoparticles for Thermoelectrics: Impact of Cu-Doping

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    The present study investigates the impact of copper doping on the thermoelectric properties of zinc selenide (ZnSe) nanoparticles synthesized by the hydrothermal method. Nanoparticle samples with varying copper concentrations were prepared and their thermoelectric performances were evaluated by measuring the electrical transport properties, the Seebeck coefficient, and extracting the power factor. The results demonstrate that the thermoelectric properties of Cu-doped ZnSe nanoparticles are significantly enhanced by doping, mainly as an effect of an improved electrical conductivity, providing a promising avenue for energy applications of these nanomaterials. To gain further insights into the fundamental mechanisms underlying the observed improvements in thermoelectric performance of the samples, the morphological, structural, and vibrational properties were characterized using a combination of scanning electron microscopy, X-ray diffraction, and Raman spectroscopy

    Growing Season Air mass Equivalent Temperature (T\u3csub\u3eE\u3c/sub\u3e) in the East Central USA

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    Equivalent temperature (TE), which incorporates both dry (surface air temperature, T) and moist heat content associated with atmospheric moisture, is a better indicator of overall atmospheric heat content compared to T alone. This paper investigates the impacts of different types of air masses on TE during the growing season (April–September). The study used data from the Kentucky Mesonet for this purpose. The growing season was divided into early (April–May), mid (June–July), and late (August–September). Analysis suggests that TE for moist tropical (MT) air mass was as high as 61 and 81 °C for the early and mid-growing season, respectively. Further analysis suggests that TE for different parts of the growing seasons were statistically significantly different from each other. In addition, TE for different air masses was also statistically significantly different from each other. The difference between TE and T (i.e. TE-T) is smaller under dry atmospheric conditions but larger under moist conditions. For example, in Barren County, the lowest difference (20–10 °C) was 10 °C. It was reported on 18 April 2010, a dry weather day. On the other hand, the highest difference for this site was 48 °C and was reported on 11 August 2010, a humid day

    A comprehensive study of chronic diabetes complications in streptozotocin-induced diabetic rat

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    Objective: The purpose of this study was to provide a reference of chronic diabetes complications by investigating the prolonged hyperglycemia effects on hematological, biochemical and histopathological changes (liver, kidney, spleen, cardiac muscle, adrenal gland, and endocrine pancreas) in diabetic rats induced by streptozotocin. Methods: Ten adult female Sprague-Dawley of uniform age were divided into two Groups. Group 1 was made diabetic by single intraperitoneal injection of streptozotocin (60 mg/kg/bw) whereas Group 2 served as control. After six months, the rats were anesthetized using pentobarbital. Cardiac puncture was performed to get 3 ml of the blood sample; following 12 hours of an overnight fast. Serum chemistry test and complete blood analysis for lipid profile and blood glucose test; liver and renal functions were performed. Tissue specimens of liver, kidney, spleen, cardiac muscle, adrenal gland, and endocrine pancreas were fixed in 10% formal saline and processed for histological study. Results: There were severe histopathological changes in the affected organs; and the presence of a significant abnormality of lipid profile, liver, and renal functions. Conclusions: The presence of histopathological changes with abnormal biochemical changes is related to the chronic absence of insulin production in the destroyed β –cells which reflect the diabetic complications in a human being

    Depression, sleeping pattern, and suicidal ideation among medical students in Bangladesh: a cross-sectional pilot study

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    © 2020, Springer-Verlag GmbH Germany, part of Springer Nature. Background: Depression is a major morbidity and the most common mental disorder among the medical students in medical schools globally. Undergraduate students suffer stress more due to their academic curriculum than the students of other faculties. In low-resource settings like Bangladesh, there is a dearth in research on the mental health of undergraduate medical students. This pilot study was conducted to add to the existing limited evidence by reporting the prevalence of depression and describing sleeping pattern and suicidal tendencies among medical students. Relevantly, we have investigated the overall mental health status among the medical students in Bangladesh. Methods: This cross-sectional study was conducted in two medical colleges of Dhaka between July 2013 and December 2013, among 221 Bangladeshi medical students from first to fifth year. By the convenience sampling technique, data were collected by a pretested, structured, self-administered questionnaire and analysis was done by SPSS version 18.0. Depression was assessed by the validated Patient Health Questionnaire-9 (PHQ-9) tool among the respondents. Goldberg’s General Health Questionnaire (GHQ-28) was used for assessing overall mental health status. Results: Depression was found in 38.9% of participants, with 3.6%, 14.5%, and 20.8% being severe, moderate, and mild depression, respectively. 17.6% of medical students had suicidal tendency or attempted suicide at least once after attending medical school. The sleeping hours were inadequate and altered after starting this stressful academic course. 33.5% of medical students had poor mental health status. There was a statistically significant association between poor mental health status in the age group less than 22 years old and initial academic study year (1st to 3rd of MBBS). Conclusion: The findings are suggestive of a higher prevalence of depression among early-year medical students and marginal predominance in males. Suicidal tendency is also higher. This calls for further investigation with situation analysis, qualitative explorations, and surveys to explore the burden of such disorders in Bangladesh

    Curcumin: Synthesis optimization and in silico interaction with cyclin dependent kinase

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    Curcumin is a natural product with enormous biological potential. In this study, curcumin synthesis was revisited using different reaction solvents, a catalyst (n-butylamine) and a water scavenger [(n-BuO)3B], to develop the optimal procedure for its rapid acquisition. During synthesis, solvent choice was found to be an important parameter for better curcumin yield and high purity. In a typical reaction, acetyl acetone was treated with boron trioxide, followed by condensation with vanillin in the presence of tri-n-butyl borate as water scavenger and n-butylamine as catalyst at 80 °C in ethyl acetate to afford curcumin. Moreover, curcumin was also extracted from turmeric powder and spectroscopic properties such as IR, MS, 1H NMR and 13C NMR with synthetic curcumin were established to identify any impurity. The purity of synthetic and extracted curcumin was also checked by TLC and HPLC-DAD. To computationally assess its therapeutic potential against cyclin dependent kinases (CDKs), curcumin was docked in different isoforms of CDKs. It was observed that it did not dock at the active sites of CDK2 and CDK6. However, it could enter into weak interactions with CDK4 protein

    Pollution Characteristics of Particulate Matter (PM2.5 and PM10) and Constituent Carbonaceous Aerosols in a South Asian Future Megacity

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    The future megacity of Faisalabad is of prime interest when considering environmental health because of its bulky population and abundant industrial and anthropogenic sources of coarse particles (PM10) and fine airborne particulate matter (PM2.5). The current study was aimed to investigate the concentration level of PM2.5 and PM10, also the characterization of carbonaceous aerosols including organic carbon (OC), elemental carbon (EC) and total carbon (TC) in PM2.5 and PM10 samples collected from five different sectors (residential, health, commercial, industrial, and vehicular zone). The data presented here are the first of their kind in this sprawling city having industries and agricultural activities side by side. Results of the study revealed that the mass concentration of PM2.5 and PM10 is at an elevated level throughout Faisalabad, with ambient PM2.5 and PM10 points that constantly exceeded the 24-h standards of US-EPA, and National Environment Quality Standards (NEQS) which poses harmful effects on the quality of air and health. The total carbon concentration varied between 21.33 and 206.84 µg/m3, and 26.08 and 211.15 µg/m3 with an average of 119.16 ± 64.91 µg/m3 and 124.71 ± 64.38 µg/m3 for PM2.5 in summer and winter seasons, respectively. For PM10, the concentration of TC varied from 34.52 to 289.21 µg/m3 with an average of 181.50 ± 87.38 µg/m3 (for summer season) and it ranged between 44.04 and 300.02 µg/m3 with an average of 191.04 ± 87.98 µg/m3 (winter season), respectively. No significant difference between particulate concentration and weather parameters was observed. Similarly, results of air quality index (AQI) and pollution index (PI) stated that the air quality of Faisalabad ranges from poor to severely pollute. In terms of AQI, moderate pollution was recorded on sampling sites in the following order; Ittehad Welfare Dispensary > Saleemi Chowk > Kashmir Road > Pepsi Factory, while at Nazria Pakistan Square and Allied Hospital, higher AQI values were recorded. The analysis and results presented in this study can be used by policy-makers to apply rigorous strategies that decrease air pollution and the associated health effects in Faisalabad.This research was funded through HEC-NRPU, grant number 5635 and the data presented here are a part of a Ph.D. thesis at GCUF. The authors further acknowledge the financial support provided by IERI-GIST project

    Enhanced hydrogen evolution reaction performance of anatase–rutile TiO2 heterojunction via charge transfer from rutile to anatase

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    This is the final version. Available on open access from the Royal Society of Chemistry via the DOI in this recordIn light of recent doubts surrounding the industrial viability of photo(electro)catalysis technology for sustainable hydrogen production, it becomes imperative to align materials development with rationalized synthesis protocols. In this study, we present an innovative technique utilizing atmospheric-pressure chemical vapor deposition (APCVD) to rapidly produce TiO2 in just 5 minutes using pure TiCl4 as the sole reagent. The resulting photoanode exhibits exceptional photoelectrochemical (PEC) water-splitting performance, achieving a photocurrent density of 2.06 mA cm−2 at 1.23 V RHE. Moreover, the photoanode demonstrates sustained operation for 16 hours, leading to the successful collection of 138 μmol of H2 and 62 μmol of O2. These remarkable results are attributed to the controlled formation of an anatase–rutile phase-junction, the presence of well-balanced oxygen vacancies, and the bifrustum nanoparticle–nanoflake structure with a unique light trapping effect and large surface area. Density functional theory calculations confirm that the water-splitting reaction primarily occurs at undercoordinated Ti and O atoms in both anatase and rutile TiO2. Notably, the calculated Gibbs free energy values for the hydrogen evolution reaction (HER) differ significantly between rutile (−0.86 eV) and anatase TiO2 (0.22 eV). In the heterojunction, charge transfer enhances the HER performance through shared electronic density, resulting in a synergistic effect that surpasses the capabilities of individual surfaces and underscores the importance of electronic interactions within the junction.Universiti Kebangsaan MalaysiaCenter of Excellence for Innovation in ChemistryProgram Management Unit for Human Resources & Institutional Development, Research and InnovationHuman Resource Development in Science Project Science Achievement Scholarship of Thailand (SAST

    Search for the Decay Υ(1S)γη\Upsilon(1S)\to \gamma\eta^{'}

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    We report on a search for the radiative decay U(1S) -> gamma + eta' in 61.3 pb^-1 of data taken with the CLEO II detector at the Cornell Electron Storage Ring. Three decay chains were investigated, all involving eta' -> pi+ pi- + eta, followed by eta -> gamma + gamma, eta -> pi0 + pi0 + pi0, or eta -> pi+ + pi- + pi0. We find no candidate events in any of the three cases and set a combined upper limit of 1.6 x 10^-5 at 90% C.L., significantly smaller than the previous limit. We compare our result to other radiative U(1S) decays, to radiative J/psi decays, and to theoretical predictions.Comment: 9 pages postscript, also available through http://w4.lns.cornell.edu/public/CLNS, submitted to PR

    Systems-Level Modeling of Cancer-Fibroblast Interaction

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    Cancer cells interact with surrounding stromal fibroblasts during tumorigenesis, but the complex molecular rules that govern these interactions remain poorly understood thus hindering the development of therapeutic strategies to target cancer stroma. We have taken a mathematical approach to begin defining these rules by performing the first large-scale quantitative analysis of fibroblast effects on cancer cell proliferation across more than four hundred heterotypic cell line pairings. Systems-level modeling of this complex dataset using singular value decomposition revealed that normal tissue fibroblasts variably express at least two functionally distinct activities, one which reflects transcriptional programs associated with activated mesenchymal cells, that act either coordinately or at cross-purposes to modulate cancer cell proliferation. These findings suggest that quantitative approaches may prove useful for identifying organizational principles that govern complex heterotypic cell-cell interactions in cancer and other contexts

    Gender differences in self reported long term outcomes following moderate to severe traumatic brain injury

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    <p>Abstract</p> <p>Background</p> <p>The majority of research on health outcomes after a traumatic brain injury is focused on male participants. Information examining gender differences in health outcomes post traumatic brain injury is limited. The purpose of this study was to investigate gender differences in symptoms reported after a traumatic brain injury and to examine the degree to which these symptoms are problematic in daily functioning.</p> <p>Methods</p> <p>This is a secondary data analysis of a retrospective cohort study of 306 individuals who sustained a moderate to severe traumatic brain injury 8 to 24 years ago. Data were collected using the Problem Checklist (PCL) from the Head Injury Family Interview (HIFI). Using Bonferroni correction, group differences between women and men were explored using Chi-square and Wilcoxon analysis.</p> <p>Results</p> <p>Chi-square analysis by gender revealed that significantly more men reported difficulty setting realistic goals and restlessness whereas significantly more women reported headaches, dizziness and loss of confidence. Wilcoxon analysis by gender revealed that men reported sensitivity to noise and sleep disturbances as significantly more problematic than women, whereas for women, lack of initiative and needing supervision were significantly more problematic in daily functioning.</p> <p>Conclusion</p> <p>This study provides insight into gender differences on outcomes after traumatic brain injury. There are significant differences between problems reported by men compared to women. This insight may facilitate health service planners and clinicians when developing programs for individuals with brain injury.</p
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