868 research outputs found

    Thermal slip in oblique radiative nano-polymer gel transport with temperature-dependent viscosity : solar collector nanomaterial coating manufacturing simulation

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    Nano-polymeric solar paints and sol-gels have emerged as a major new development in solar cell/collector coatings offering significant improvements in durability, anti-corrosion and thermal efficiency. They also exhibit substantial viscosity variation with temperature which can be exploited in solar collector designs. Modern manufacturing processes for such nano-rheological materials frequently employ stagnation flow dynamics under high temperature which invokes radiative heat transfer. Motivated by elaborating in further detail the nanoscale heat, mass and momentum characteristics, the present article presents a mathematical and computational study of the steady, two-dimensional, non-aligned thermo-fluid boundary layer transport of copper metal-doped water-based nano-polymeric sol gels under radiative heat flux. To simulate real nano-polymer boundary interface dynamics, thermal slip is analysed at the wall. A temperature-dependent viscosity is also considered. The conservation equations for mass, normal and tangential momentum and energy are normalized via appropriate transformations to generate a multi-degree, ordinary differential, non-linear, coupled boundary value problem. Numerical solutions are obtained via the stable, efficient Runge-Kutta-Fehlberg scheme with shooting quadrature in MATLAB symbolic software. Validation of solutions is achieved with a Variational Iterative Method (VIM) utilizing Langrangian multipliers. The impact of key emerging dimensionless parameters i.e. obliqueness parameter, radiation-conduction Rosseland number (Rd), thermal slip parameter (ALPHA), viscosity parameter (m), nanoparticles volume fraction (PHI) on non-dimensional normal and tangential velocity components, temperature, wall shear stress, local heat flux and streamline distributions is visualized graphically. Shear stress and temperature are boosted with increasing radiative effect whereas local heat flux is reduced. Increasing wall thermal slip parameter depletes temperatures

    Meglumine catalyzed one-pot green synthesis of novel 4,7-dihydro-1H-pyrazolo3,4-bpyridin-6-amines

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    Meglumine efficiently catalyzes the one-pot, five-component reaction of hydrazine, ethyl acetoacetate, aryl aldehydes, substituted phenylacetonitriles and ammonium acetate in ethanol at room temperature to afford novel 4,7-dihydro-1H-pyrazolo3,4-bpyridin-6-amine derivatives. The present approach offers several advantages such as shorter reaction durations, low cost, excellent yields, milder reaction conditions, simple workup procedure and is environment friendly. All the synthesized derivatives are characterized by IR,1H NMR,13C NMR, HRMS and CHN analysis. � 2016 Mohamed Afzal Pash

    SELINDA: a secure, scalable and light-weight data collection protocol for smart grids

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    Security in the smart grid is a challenge as an increasing number of sensors and measurement devices are connected to the power grid. General purpose security protocols are not suitable for providing data security to devices with limited memory, computational power and network connectivity. In this paper, we develop a secure and light-weight scalable security protocol that allows a power system operator (PO) to collect data from measurement devices (MDs) using data collectors (DCs). The security protocol trades off between computations and device memory requirements and provides flexible association between DC and MDs. These features allow data to be securely transferred from MDs to PO via mobile or untrustworthy DCs. We analyze the complexity and security of the protocol and validate its performance using experiments. Our results confirm that our proposed protocol collects data in a secure, fast and efficient manner. © 2013 IEEE.published_or_final_versio

    A mediation approach to understanding socio-economic inequalities in maternal health-seeking behaviours in Egypt.

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    BACKGROUND: The levels and origins of socio-economic inequalities in health-seeking behaviours in Egypt are poorly understood. This paper assesses the levels of health-seeking behaviours related to maternal care (antenatal care [ANC] and facility delivery) and their accumulation during pregnancy and childbirth. Secondly, it explores the mechanisms underlying the association between socio-economic position (SEP) and maternal health-seeking behaviours. Thirdly, it examines the effectiveness of targeting of free public ANC and delivery care. METHODS: Data from the 2008 Demographic and Health Survey were used to capture two latent constructs of SEP: individual socio-cultural capital and household-level economic capital. These variables were entered into an adjusted mediation model, predicting twelve dimensions of maternal health-seeking; including any ANC, private ANC, first ANC visit in first trimester, regular ANC (four or more visits during pregnancy), facility delivery, and private delivery. ANC and delivery care costs were examined separately by provider type (public or private). RESULTS: While 74.2% of women with a birth in the 5-year recall period obtained any ANC and 72.4% delivered in a facility, only 48.8% obtained the complete maternal care package (timely and regular facility-based ANC as well as facility delivery) for their most recent live birth. Both socio-cultural capital and economic capital were independently positively associated with receiving any ANC and delivering in a facility. The strongest direct effect of socio-cultural capital was seen in models predicting private provider use of both ANC and delivery. Despite substantial proportions of women using public providers reporting receipt of free care (ANC: 38%, delivery: 24%), this free-of-charge public care was not effectively targeted to women with lowest economic resources. CONCLUSIONS: Socio-cultural capital is the primary mechanism leading to inequalities in maternal health-seeking in Egypt. Future studies should therefore examine the objective and perceived quality of care from different types of providers. Improvements in the targeting of free public care could help reduce the existing SEP-based inequalities in maternal care coverage in the short term

    ANALYTICAL METHOD DEVELOPMENT AND VALIDATION STUDIES OF TICAGRELOR TABLETS BY RP-HPLC

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    Objective: The present study was conducted to develop a simple and precise analytical method for the estimation of ticagrelor in tablet formulation.Methods: Reverse Phase HPLC was used for method development and validation studies of ticagrelor. The optimum chromatographic conditions comprised of C18 column (Kromasil, 250×4.6 mm, 5 µ) as the stationary phase and aqueous buffer (containing 0.5 ml formic acid and triethylamine each in water) and acetonitrile in the ratio of 50:50 v/v as the mobile phase. The flow rate was 1.3 ml/min with detection at 256 nm and a run time of 6 min. Forced degradation studies were conducted and the isocratic mode was modified to a gradient mode to make the method stability indicating in nature.Results: The retention time of ticagrelor was 3.372 min. The linearity studies indicated that the range of the developed method was 20-90 ppm with a correlation coefficient of 0.9956. The method was specific with a percent mean recovery was found to be 99.93%.. The % RSD in the precision studies was 0.069. The validated method was applied to conduct the assay of ticagrelor in tablets and the with a percent mean recovery of 99.82%. The modified method was capable of resolving 13 related substances from the ticagrelor peak in the forced degradation studies.Conclusion: The developed and validated RP-HPLC isocratic method was simple, accurate and precise as per the ICH guidelines. It was suitable for the analysis of ticagrelor in bulk and tablet formulation. The modified gradient method can be used to resolve the in-process impurities and related substances and can be directly applied to liquid chromatography hyphenated with mass spectroscopy (LC/MS) studies with minor modifications for identification of related substances

    Cohort Profile: The Flu Watch Study

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    Influenza is a common, highly contagious respiratory virus which infects all age groups, causing a range of outcomes from asymptomatic infection and mild respiratory disease to severe respiratory disease and death.1 If infected, the adaptive immune system produces a humoral (antibody) and cell-mediated (T cell) immune response to fight the infection.2 Influenza viruses continually evolve through antigenic drift, resulting in slightly different ‘seasonal’ influenza strains circulating each year. Population-level antibody immunity to these seasonal viruses builds up over time, so in any given season only a proportion of the population is susceptible to the circulating strains. Occasionally, influenza A viruses evolve rapidly through antigenic shift by swapping genes with influenza viruses usually circulating in animals. This process creates an immunologically distinct virus to which the population may have little to no antibody immunity. The virus can result in a pandemic if a large portion of the population is susceptible and the virus is easily spread

    Genome-wide association study for type 2 diabetes in Indians identifies a new susceptibility locus at 2q21

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    Meta-AnalysisThis is the final version of the article. Available from the American Diabetes Association via the DOI in this record.Indians undergoing socioeconomic and lifestyle transitions will be maximally affected by epidemic of type 2 diabetes (T2D). We conducted a two-stage genome-wide association study of T2D in 12,535 Indians, a less explored but high-risk group. We identified a new type 2 diabetes-associated locus at 2q21, with the lead signal being rs6723108 (odds ratio 1.31; P = 3.32 × 10⁻⁹). Imputation analysis refined the signal to rs998451 (odds ratio 1.56; P = 6.3 × 10⁻¹²) within TMEM163 that encodes a probable vesicular transporter in nerve terminals. TMEM163 variants also showed association with decreased fasting plasma insulin and homeostatic model assessment of insulin resistance, indicating a plausible effect through impaired insulin secretion. The 2q21 region also harbors RAB3GAP1 and ACMSD; those are involved in neurologic disorders. Forty-nine of 56 previously reported signals showed consistency in direction with similar effect sizes in Indians and previous studies, and 25 of them were also associated (P < 0.05). Known loci and the newly identified 2q21 locus altogether explained 7.65% variance in the risk of T2D in Indians. Our study suggests that common susceptibility variants for T2D are largely the same across populations, but also reveals a population-specific locus and provides further insights into genetic architecture and etiology of T2D.The major funding for this work comes from Council for Scientific and Industrial Research, Government of India, in the form of the grant “Diabetes mellitus—New drug discovery R&D, molecular mechanisms, and genetic and epidemiological factors” (NWP0032-19). R.T. received a postdoctoral fellowship from the Fogarty International Center and the Eunice Kennedy Shriver National Institute of Child Health and Human Development at the National Institutes of Health (D43-HD-065249)

    Bilateral systematised epidermolytic epidermal nevus: A case report

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    Verrucous epidermal nevi (VEN) are benign congenital hamartomas consisting of keratinocytes. Histological examination mostly exhibits hyperkeratosis, acanthosis, papillomatosis and, rarely, the features of epidermolytic hyperkeratosis (EHK). We report a case of a 6-year-old boy who presented at Aga Khan University Hospital, Karachi, Pakistan with bilaterally symmetrical linear epidermal nevi following Blaschko\u27s lines and showing epidermolytic hyperkeratosis on histology. The patient was treated with topical keratolytics and emolients which led to considerable improvement. To the best of the authors\u27 knowledge, this is the first report of VEN from Pakistan
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