323 research outputs found

    Thermodynamic efficiency limits of classical and bifacial multi-junction tandem solar cells: An analytical approach

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    Bifacial tandem cells promise to reduce three fundamental losses (i.e., above-bandgap, below bandgap, and the uncollected light between panels) inherent in classical single junction photovoltaic (PV) systems. The successive filtering of light through the bandgapcascade and the requirement of current continuity make optimization of tandem cellsdifficult and accessible only to numerical solution through computer modeling. The challenge is even more complicated for bifacial design. In this paper, we use an elegantly simple analytical approach to show that the essential physics of optimization is intuitively obvious, and deeply insightful results can be obtained with a few lines of algebra. This powerful approach reproduces, as special cases, all of the known results of conventional and bifacial tandem cells and highlights the asymptotic efficiency gain of these technologies

    Antioxidant, antimicrobial and cytotoxic activities of Corypha taliera Roxb

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    The methanol extract of Corypha taliera fruits as well as its n-hexane, carbon tetrachloride, dichloromethane and aqueous soluble fractions were subjected to screening for antioxidant, antimicrobial and cytotoxic activities. The methanolic crude extract exhibited the highest antioxidant activity (IC50 19.33 μg/ml as compared to 9.5 μg/ml for the standard agent, BHT). The crude methanol extract and its carbon tetrachloride, dichloromethane and aqueous soluble fractions showed mild to moderate inhibition of microbial growth against some of the tested organisms. All the extractives exhibited strong cytotoxic properties, among which the methanol extract revealed the strongest cytotixicity (LC50 = 0.43 μg/ml).Colegio de Farmacéuticos de la Provincia de Buenos Aire

    Antioxidant, antimicrobial and cytotoxic activities of Corypha taliera Roxb

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    The methanol extract of Corypha taliera fruits as well as its n-hexane, carbon tetrachloride, dichloromethane and aqueous soluble fractions were subjected to screening for antioxidant, antimicrobial and cytotoxic activities. The methanolic crude extract exhibited the highest antioxidant activity (IC50 19.33 μg/ml as compared to 9.5 μg/ml for the standard agent, BHT). The crude methanol extract and its carbon tetrachloride, dichloromethane and aqueous soluble fractions showed mild to moderate inhibition of microbial growth against some of the tested organisms. All the extractives exhibited strong cytotoxic properties, among which the methanol extract revealed the strongest cytotixicity (LC50 = 0.43 μg/ml).Colegio de Farmacéuticos de la Provincia de Buenos Aire

    Factors Associated with Depression among University Students in Malaysia: A Cross-sectional Study

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    Depression is a recurrent mental health problem among younger demographics, and university students are particularly susceptible owing to stress, workload and independent living, amongst other factors.  This study explores the prevalence of depression and the factors influencing depression among university students in Malaysia. This cross-sectional study involved 1,023 university students (response rate 90.4%). Depression was assessed using the Centre for Epidemiological Studies Short Depression Scale (CESD -10). Binary logistic regression was used to determine predictors of depression based on sociodemographic, physiological, lifestyle, and health characteristics. Approximately 30% of respondents experienced depression, and 4.4% of this category suffered severe depression. This study demonstrates that instances of depression were 2.52 times higher (95% CI: 1.71-3.71) in second year students compared to first year students, and 1.63 times higher (95% CI: 1.08-2.45) in students staying outside campus compared to students staying inside campus. Students from poor, not well-off, and quite well-off family background had 15.26 (95% CI: 2.77-84.88), 4.85 (95% CI: 1.01-23.34) and 5.62 times (95% CI: 1.16-27.25) higher chance for depression than wealthier students, respectively. Students with mild, moderate, and severe sleeping problems were 2.50 times (95% CI: 1.61-3.88), 3.34 times (95% CI: 2.18-5.11), and 3.66 times (95% CI: 1. 93 -6. 94) more likely to be depressed than those without sleeping problem, respectively. Students with post-traumatic stress disorder (PTSD) were 1.42 times higher (95% CI: 1.07-2.56) to suffer from depression. This study concludes that higher education institutions need to pay special attention to the mental health of those students especially those in their second year, living off campus, from lower economic backgrounds, with sleeping problem, or suffering PTSD

    Creek`s Aquaculture Techniques in Rangamati Hill Tracts of Bangladesh

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    An experiment was conducted in nine suitable (average .10±2 ha) creeks of Rangamati hill tracts Bangladesh viz., of Langadu, Naniarchar and Sadar Upazila for evaluating growth, survival and production performance of Indian major carps (Labeo rohita, Catla catla, Cirrhinus mrigala) in a completely randomized design into three different treatments with three replications for a period of one year. Stocking density, growth, survival was checked periodically and total yield calculated from stocking and harvesting data. A significant spatial variation in specific growth rate (SGR) and yields was found despite uniform stocking densities, attributable to variation in environmental parameters. Among the results rohu was found to have comparatively higher SGR of 1.51±0.55 in Naniarchar where as langadu creek was reported with higher SGR of 1.46±0.94, 1.57±0.41 and 1.46 ±.64 for rohu catla, and mrigal. Rangamati sadar Upazilla creek was found to be conducive to Catla with a SGR of 1.55±.78. In general, higher gross and net productions were reported from Sadar Upazilla, Langadu and Naniarchar creeks, suggestive of its suitability for developing creeks aquaculture technology. However research findings will help the community of Chittagong hill tracts by giving appropriate technology for sustainable fish production in creeks

    Effect of a randomised exclusive breastfeeding counselling intervention nested into the MINIMat prenatal nutrition trial in Bangladesh.

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    AIM: It is unknown whether maternal malnutrition reduces the effect of counselling on exclusive breastfeeding. This study evaluated the effect of breastfeeding counselling on the duration of exclusive breastfeeding, and whether the timing of prenatal food and different micronutrient supplements further prolonged this duration. METHODS: Pregnant women in Matlab, Bangladesh, were randomised to receive daily food supplements of 600 kcal at nine weeks of gestation or at the standard 20 weeks. They also were allocated to either 30 mg of iron and 400 μg folic acid, or the standard programme 60 mg of iron and folic acid or multiple micronutrients. At 30 weeks of gestation, 3188 women were randomised to receive either eight breastfeeding counselling sessions or the usual health messages. RESULTS: The median duration of exclusive breastfeeding was 135 days in the counselling group and 75 days in the usual health message group (p < 0.001). Prenatal supplements did not modify the effects of counselling. Women in the usual health message group who were randomised to multiple micronutrients exclusively breastfed for 12 days longer than mothers receiving the standard iron-folate combination (p = 0.003). CONCLUSION: Breastfeeding counselling increased the duration of exclusive breastfeeding by 60 days. This duration was not influenced by the supplements

    A practical guide to single-cell RNA- sequencing for biomedical research and clinical applications

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    RNA sequencing (RNA-seq) is a genomic approach for the detection and quantitative analysis of messenger RNA molecules in a biological sample and is useful for studying cellular responses. RNA-seq has fueled much discovery and innovation in medicine over recent years. For practical reasons, the technique is usually conducted on samples comprising thousands to millions of cells. However, this has hindered direct assessment of the fundamental unit of biology—the cell. Since the first single-cell RNA-sequencing (scRNA-seq) study was published in 2009, many more have been conducted, mostly by specialist laboratories with unique skills in wet-lab single-cell genomics, bioinformatics, and computation. However, with the increasing commercial availability of scRNA-seq platforms, and the rapid ongoing maturation of bioinformatics approaches, a point has been reached where any biomedical researcher or clinician can use scRNA-seq to make exciting discoveries. In this review, we present a practical guide to help researchers design their first scRNA-seq studies, including introductory information on experimental hardware, protocol choice, quality control, data analysis and biological interpretation.  </div

    Early Invitation to Food And/Or Multiple Micronutrient Supplementation in Pregnancy Does Not Affect Body Composition in Offspring at 54 Months: Follow-Up of the MINImat Randomized Trial, Bangladesh

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    Growth patterns in early life are associated with later health.The effect of nutrition duringin uterodevelopmenton later body composition is unclear. We evaluated whether prenatal early invitation to food and/or multiplemicronutrient supplementation (MMS) in pregnancy has an effect on offspring body composition at 54 monthsof age. In Maternal and Infant Nutrition Interventions in Matlab trial (ISRCTN16581394) in Bangladesh, 4436pregnant women were randomised into six equally sized groups: double-masked supplementation with capsulesof either 30 mg Fe and 400mg folic acid, or 60 mg Fe and 400mg folic acid, or MMS (15 micronutrients), wascombined with a randomised early invitation (around 9 weeks) or a usual invitation (around 20 weeks) to startfood supplementation (608 kcal 6 days per week). At 54 months, the body composition of the offspring wasassessed by leg-to-leg bioelectrical impedance analysis. Of the 3267 live singletons with birth anthropometry,2290 children were measured at 54 months,representing 70% of the live births.There was no interaction betweenthe food and micronutrient supplementation on body composition outcomes. There were no significant differ-ences in a range of anthropometric and body composition measurements, including weight, height, mid-upperarm circumference, head circumference, skinfold thickness, and fat mass and fat-free mass between the differentprenatal food and micronutrient groups using an intention-to-treat analysis. This analysis shows that earlyinvitation to food supplementation and MMS provided to rural Bangladeshi women during pregnancy did notaffect offspring body composition at 54 months of age
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