837 research outputs found

    Design, development, and characterization of low distortion advanced semitransparent photovoltaic glass for buildings applications

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    Aesthetic appearance of building-integrated photovoltaic (BIPV) products, such as semi-transparent PV (STPV) glass, is crucial for their widespread adoption and contribution to the net-zero energy building (NZEB) goal. However, the visual distortion significantly limits the aesthetics of STPV glass. In this study, we investigate the distortion effect of transparent periodic-micropattern-based thin-film PV (PMPV) panels available in the market. To minimize the visual distortion of such PMPV glass panel types, we design and develop an aperiodic micropattern-based PV (APMP) glass that significantly reduces visual distortion. The developed APMP glass demonstrates a haze ratio of 3.7% compared to the 10.7% of PMPV glass. Furthermore, the developed AMPV glass shows an average visible transmittance (AVT) of 58.3% which is around 1.3 times higher than that of AMPV glass (43.8%). Finally, the measured CIELAB values (L* = 43.2, a* = −1.55, b* = −2.86.) indicate that our developed AMPV glass possesses excellent color neutrality, which makes them suitable for commercial applications. Based on the characterization results, this study will have a significant impact on the areas of smart window glasses that can play a vital role in developing a sustainable environment and enhancing the aesthetical appearance of net-zero energy buildings (NZEB)

    Delamination-and electromigration-related failures in solar panels—a review

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    The reliability of photovoltaic (PV) modules operating under various weather conditions attracts the manufacturer’s concern since several studies reveal a degradation rate higher than 0.8% per year for the silicon-based technology and reached up to 2.76% per year in a harsh climate. The lifetime of the PV modules is decreased because of numerous degradation modes. Electromigration and delamination are two failure modes that play a significant role in PV modules’ output power losses. The correlations of these two phenomena are not sufficiently explained and understood like other failures such as corrosion and potential-induced degradation. Therefore, in this review, we attempt to elaborate on the correlation and the influence of delamination and electromigration on PV module components such as metallization and organic materials to ensure the reliability of the PV modules. Moreover, the effects, causes, and the sites that tend to face these failures, particularly the silicon solar cells, are explained in detail. Elsewhere, the factors of aging vary as the temperature and humidity change from one country to another. Hence, accelerated tests and the standards used to perform the aging test for PV modules have been covered in this review

    Green training and development revolutionizing organizational performance : the moderating role of green employee involvement in the Bangladeshi pharmaceutical industry

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    Green Human Resource Management (GHRM) has been found to positively affect job satisfaction (JS) and job performance as employees are more engaged and motivated to improve organizational performance (OP). However, few studies have investigated this phenomenon, and none have examined green employee involvement (GEI) within the Bangladeshi context. Therefore, this study examines the moderating role of GEI and the mediating role of JS and employee motivation (EM) on green training and development (GTD), organizational commitment (OC), and OP among pharmaceutical companies in Bangladesh and contributes to the theories of action and job performance and of ability-motivation-opportunity. Self-administered surveys were sent to executives working in 10 pharmaceutical companies in Bangladesh, and data were collected from 180 respondents using convenience sampling. These findings show that the GTD positively influenced OC and OP. Additionally, GEI played a significant moderating role between GTD and OC and GTD and OP. The study also revealed that JS played a significant mediating role between GTD and OC and, GTD, and OP. However, EM did not play a mediating role between GTD and OC and GTD and OP. Based on the research findings, pharmaceutical companies in Bangladesh should embrace GHRM practices, prioritize GTD, foster EI, and nurture JS, which are crucial for enhancing OC and OP. These recommendations contribute to a better understanding of sustainable HR practices and underscore the importance of aligning environmental goals with organizational success. The limitations of this study include limited generalizability, convenience sampling, cross-sectional design, self-report bias, limited mediation analysis, and omitted variables. To address these limitations, future research should employ a more diverse and representative sample, use longitudinal designs to establish causal relationships, incorporate qualitative methods to gather in-depth insights, and include a broader range of variables

    Efficacy and Safety of Methotrexate in Articular and Cutaneous Manifestations of systemic Lupus Erythematosus

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    Aim:  A prospective open-label study comparing the efficacy and safety of methotrexate (MTX) and chloroquine (CQ) in articular and cutaneous manifestations of systemic lupus erythematosus (SLE). Methods:  Consecutive SLE patients were randomly assigned to either 10 mg MTX weekly or 150 mg CQ daily during 24 weeks. Outcome measures were: numbers of swollen and tender joints, duration of morning stiffness, visual analog scale (VAS) for articular pain, physician global assessment index, patient global assessment index, SLE Disease Activity Index (SLEDAI), disappearance of skin rash and erythrocyte sedimentation rate (ESR). Results:  Forty-one patients consented to participate, 15 were allocated in the MTX group and 26 in the CQ group. Two patients on MTX dropped out due to side-effects and two in the CQ group, one due to side-effects and one due to inefficacy. Baseline demographic, clinical and laboratory parameters of the two groups were nearly identical. In both groups the clinical and laboratory parameters improved significantly over 24 weeks, except the ESR in the MTX group. The results of the outcome measures at the end of the trial did not differ significantly between the two groups, except morning stiffness (P < 0.05 in favor of the MTX group) and ESR (P < 0.01 in favor of the CQ group). Rise of serum alanine aminotransferase was observed in two cases in the MTX group and in none in the CQ group. Conclusion:  Low-dose MTX appears to be as effective as CQ in patients with articular and cutaneous manifestations of SLE, having an acceptable toxicity profile. Results of this prospective study need to be confirmed in a larger study

    Assessment of Maximum Bite Force in Oral Submucous Fibrosis Patients: A Preliminary Study

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    Objective: To determine the maximum bite force (MBF) in oral submucous fibrosis (OSMF) patients and to compare them with that of healthy subjects. Material and Methods: Twenty patients who were clinically confirmed, as OSMF and 20 healthy controls matched for age, gender, and number of intact functional teeth were included in this study. For each subject, age, gender, weight, height and body mass index (BMI) were recorded. The MBF registration was carried out by the two evaluators, who were previously calibrated. Bite force was measured in the first molar region using a force transducer occlusal force meter for each subject seated at the upright position, with Frankfort's plane nearly parallel to the floor, and no head support. The Student’s independent t-test was used to determine the statistical significance in relation to mean height, weight, BMI and the presence of number of intact teeth and MBF between the healthy subjects and OSMF individuals. A comparison of grades of OSMF with all variables was carried out by one-way ANOVA test. Results: No significant difference was found in mean age, mean height, weight, BMI and the presence of the number of intact teeth between healthy individuals and OSMF patients. The mean MBF in healthy subjects was 628.23 ± 24.39 N and 635.47 ± 31.22 N in OSMF patients. Even though the healthy subjects reported a higher MBF than OSMF patients did, the difference was statistically non-significant. With regards to sides, no significant difference was observed in mean MBF in healthy subjects and OSMF patients on the right (p=0.7818) and left side (p=0.6154). Conclusion: The healthy subjects reported higher MBF values than OSMF patients did and the difference was statistically non-significant

    New flavonoids from the Saudi Arabian plant:Retama raetam which stimulates secretion of insulin and inhibits α-glucosidase

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    Retama raetam is a bush which is a member of the family Fabaceae. It is used traditionally in North Africa and Saudi Arabia for the treatment of diabetes. Several flavonoids and alkaloids are already known from this plant. Chromatographic fractionation and purification led to the isolation of three new derivatives of prenylated flavones, retamasin C-E, and four new derivatives of prenylated isoflavones, retamasin F-I, in addition to two isoflavones which have not been previously reported in this plant. Particularly interesting structures included isoflavones containing 3,5-dihydro-2H-2,5-methanobenzo[e][1,4]dioxepine and 3a,8b-dihydro-7-hydroxyfuro[3,2-b]benzo[2,1-d]furan units, both of which are new amongst natural product flavonoids. Five new examples (two flavones and three isoflavones) strongly enhanced the glucose-triggered release of insulin by murine pancreatic islets and one isoflavone was a potent inhibitor of α-glucosidase. This study may rationalise the traditional medicinal use of R. raetam and provide new leads for drug design in the treatment of diabetes.</p

    Risk factors for respiratory failure in Guillain-Barre syndrome in Bangladesh: a prospective study

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    Objective: We investigated clinical, biological, and electrophysiological risk factors for mechanical ventilation (MV) and patient outcomes in Bangladesh using one of the largest, prospective Guillain-Barre syndrome (GBS) cohorts in developing world. Methods: A total of 693 GBS patients were included in two GBS studies conducted between 2006 and 2016 in Dhaka, Bangladesh. Associations between baseline characteristics and MV were tested using Fisher’s exact test, v2 test, or Mann–Whitney U-test, as appropriate. Risk factors for MV were assessed using multivariate logistic regression. Survival analysis was performed using Kaplan–Meier method; comparisons between groups performed using logrank test. Results: Of 693 patients, 155 (23%) required MV (median age, 26 years; interquartile range [IQR] 17–40). Among the ventilated patients, males were predominant (68%) than females. The most significant risk factor for MV was bulbar involvement (adjusted odds ratio [AOR]:19.07; 95% CI = 89.00– 192.57, P = 0.012). Other independently associated factors included dysautonomia (AOR:4.88; 95% CI = 1.49–15.98, P = 0.009) and severe muscle weakness at study entry (AOR:6.12; 95% CI = 0.64–58.57, P = 0.048). At 6 months after disease onset, 20% of ventilated and 52% of non-ventilated patients (P < 0.001) had recovered completely or with minor symptoms. Mortality rate was significantly higher among ventilated patients than non-ventilated patients (41% vs. 7%, P < 0.001). Interpretation: Bulbar involvement, dysautonomia and severe muscle weakness were identified as the most important risk factors for MV among GBS patients from Bangladesh. The findings may help to develop predictive models for MV in GBS in developing countries to identify impending respiratory failure and proper clinical management of GBS patients

    An integrated solar thermal and photovoltaic system

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    For the conversion of solar irradiation directly to electricity, Photovoltaic (PV) cells play an excellent role. Absorption of radiation beyond wave length 0.35 – 0.82 µm leads to a rise in temperature and the performance is significantly reduced as a result of temperature rise. Many attempts have been made to maintain the operating temperature of the PV cells as low as possible using both water and air cooling system fitted at the back of the panel. In this project, extensive indoor and outdoor tests have been performed to develop an integrated system to filter component of solar irradiation contributing to a temperature rise of the PV panel. For indoor tests, a Compact Source Iodide (CSI) lamp has been used to conduct experiments under controlled conditions. The outdoor test was conducted under the meteorological conditions of Singapore. The component of interest, which produces electricity, will be delivered to PV cells and, hence, there will no heating effect and performance degradation. A layer of water of about 15 mm can eliminate the components of the radiation not contributing to electricity generation. Also, absorbed radiation at the water filter enables to provide hot water

    Rapid automated diagnosis of diabetic peripheral neuropathy with in vivo corneal confocal microscopy

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    Purpose. To assess the diagnostic validity of a fully automated image analysis algorithm of in vivo confocal microscopy images in quantifying corneal subbasal nerves to diagnose diabetic neuropathy. Methods. One hundred eighty-six patients with type 1 and type 2 diabetes mellitus (T1/ T2DM) and 55 age-matched controls underwent assessment of neuropathy and bilateral in vivo corneal confocal microscopy (IVCCM). Corneal nerve fiber density (CNFD), branch density (CNBD), and length (CNFL) were quantified with expert, manual, and fully-automated analysis. The areas under the curve (AUC), odds ratios (OR), and optimal thresholds to rule out neuropathy were estimated for both analysis methods. Results. Neuropathy was detected in 53% of patients with diabetes. A significant reduction in manual and automated CNBD (P &lt;0.001) and CNFD (P &lt;0.0001), and CNFL (P &lt;0.0001) occurred with increasing neuropathic severity. Manual and automated analysis methods were highly correlated for CNFD (r = 0.9, P &lt;0.0001), CNFL (r = 0.89, P &lt;0.0001), and CNBD (r = 0.75, P &lt;0.0001). Manual CNFD and automated CNFL were associated with the highest AUC, sensitivity/specificity and OR to rule out neuropathy. Conclusions. Diabetic peripheral neuropathy is associated with significant corneal nerve loss detected with IVCCM. Fully automated corneal nerve quantification provides an objective and reproducible means to detect human diabetic neuropathy. © 2014 The Association for Research in Vision and Ophthalmology, Inc
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