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Impact of maternal HIV seroconversion during pregnancy on early mother to child transmission of HIV (MTCT) measured at 4-8 weeks postpartum in South Africa 2011-2012: A national population-based evaluation
No full textBackground: Mother-to-child transmission of HIV (MTCT) depends on the timing of HIV infection. We estimated HIV-seroconversion during pregnancy (HSP) after having a HIV-negative result antenatally, and its contribution to early MTCT in South Africa (SA). Methods and Findings: Between August 2011 and March 2012, we recruited a nationally representative sample of mother-infant pairs with infants aged 4-to-8 weeks from 578 health facilities. Data collection included mother interviews, child health-card reviews, and infant dried-blood-spots sample (iDBS). iDBS were tested for HIV antibodies and HIV-deoxyribonucleic-acid (HIV-DNA). HSP was defined as maternal self-report of an HIV-negative test during this pregnancy, no documented use of antiretroviral drugs and a matched HIV sero-positive iDBS. We used 20 imputations from a uniform distribution for time from reported antenatal HIV-negative result to delivery to estimate time of HSP. Early MTCT was defined based on detection of HIV-DNA in iDBS. Estimates were adjusted for clustering, nonresponse, and weighted by SA\u27s 2011 live-births. Results: Of 9802 mother-infant pairs, 2738 iDBS were HIV sero-positive, including 212 HSP, resulting in a nationally weighted estimate of 3.3% HSP (95% Confidence Interval: 2.8%-3.8%). Median time of HIV-seroconversion was 32.8weeks gestation;28.3% (19.7%- 36.9%) estimated to be \u3e36 weeks. Early MTCT was 10.7%for HSP (6.2%-16.8%) vs. 2.2% (1.7%-2.8%) for mothers with known HIV-positive status. Although they represent 2.2% of all mothers and 6.7% of HIV-infected mothers, HSP accounted for 26% of early MTCT. Multivariable analysis indicated the highest risk for HSP was among women who knew the baby\u27s father was HIV-infected (adjusted-hazard ratio (aHR) 4.71; 1.49-14.99), or who had been screened for tuberculosis (aHR 1.82; 1.43-2.32). Conclusions: HSP risk is high and contributes significantly to early MTCT. Identification of HSP by repeat-testing at 32 weeks gestation, during labor, 6 weeks postpartum, in tuberculosis-exposed women, and in discordant couples might reduce MTCT
Chitosan-based nanocomposite scaffolds for tissue engineering applications
No full textThis article reports the fabrication of three-dimensional porous chitosan and hydroxyapatite (HA)/chitosan composite scaffolds by the thermally induced phase separation (TIPS) technique, for bone tissue engineering. Different amounts of HA nanoparticles (10%, 20%, and 30% g/g) were added to the chitosan solution to produce HA/chitosan composite scaffolds of varying compositions. The morphology and pore structure of the scaffolds vis-à-vis composition were characterized using scanning electron microscopy (SEM) and an energy dispersive X-ray (EDX). Both pure chitosan and HA/chitosan composite scaffolds were highly porous and had interconnected pores. The pore sizes ranged from several micrometers to a few hundred micrometers. The HA nanoparticles were well dispersed and physically coexisted with chitosan in the composite scaffolds. However, some agglomeration of HA nanoparticles was observed on the surface of pore walls when a relatively large amount of HA was used. The composite 3D scaffolds are very promising for use in bone tissue engineering application. © 201
Sustainable public housing transformation in the convergence of emic and etic paradigms
No full textRecent studies on the global ideology of public housing are significantly focused on the cultural values of inhabitants. Thus rapid transformation of originally design housing units that are based on modern standards by inhabitants is widespread. The emic and etic principles was used to evaluate existing situation where indigenous culture inclusive housing demand is on the rise. Retrospectively, established principles of emic and etic concept in directing public housing design was measured to test the synthesis- an interphase thought to provide sustainability amidst conflicting indigenous space demand and regulated homogenous designs. The study uncovered a chaotic but culture-specific genesis that comprise of formalized antecedents that can no longer be ignored, but lacks standardisation. Instead, the etic and emic interphase (convergences) remains a delusion proffering unintended solutions. Implacably, rigour in the concept of culture bonds sustainability process in public housing, hence its standardization is required to be undertaken in order to clarify and process the potentials of the alternative (the intersection) to the etic and emic approaches
F–Geometric Mean Graphs
Get PDFIn a study of traffic, the labelling problems in graph theory can be used by considering the crowd at every junction as the weights of a vertex and expected average traffic in each street as the weight of the corresponding edge. If we assume the expected traffic at each street as the arithmetic mean of the weight of the end vertices, that causes mean labelling of the graph. When we consider a geometric mean instead of arithmetic mean in a large population of a city, the rate of growth of traffic in each street will be more accurate. The geometric mean labelling of graphs have been defined in which the edge labels may be assigned by either flooring function or ceiling function. In this, the readers will get some confusion in finding the edge labels which edge is assigned by flooring function and which edge is assigned by ceiling function. To avoid this confusion, we establish the F-geometric mean labelling on graphs by considering the edge labels obtained only from the flooring function. An F-Geometric mean labelling of a graph G with q edges, is an injective function from the vertex set of G to {1, 2, 3,..., q +1} such that the edge labels obtained from the flooring function of geometric mean of the vertex labels of the end vertices of each edge, are all distinct and the set of edge labels is {1, 2, 3,..., q}. A graph is said to be an F–Geometric mean graph if it admits an F–Geometric mean labelling. In this paper, we study the F-geometric meanness of the graphs such as cycle, star graph, complete graph, comb, ladder, triangular ladder, middle graph of path, the graphs obtained from duplicating arbitrary vertex by a vertex as well as arbitrary edge by an edge in the cycle and subdivision of comb and star graph
Algorithm for Solving Tri-diagonal Finite Volume Discretized Linear Systems
Get PDFIn this paper we present efficient computational algorithms for solving finite volume discretized tri-diagonal linear systems. The implementation of the algorithm for steady state finite volume structured grids linear system using MS Excel is presented. An example is given in order to illustrate the algorithms
Unsteady boundary layer flow of thermophoretic MHD nanofluid past a stretching sheet with space and time dependent internal heat source/sink
Get PDFIn this study we analyze the boundary layer flow of a thermophoretic magnetohydrodynamic dissipative nanofluid over an unsteady stretching sheet in a porous medium with space and time dependent internal heat source/sink. The governing equations are transformed to ordinary differential equations by using similarity transformation. Numerical solutions of these equations are obtained by using the Shooting Technique. The effects of non-dimensional governing parameters on the velocity, temperature, concentration profiles, friction factor, Nusselt and Sherwood numbers are discussed and presented through graphs and tables. Accuracy of the results compared with the existing ones. Excellent agreement is found with earlier studies
Suspension model for blood flow through a tapering catheterized inclined artery with asymmetric stenosis
Get PDFWe intend to study a particle fluid suspension model for blood flow through an axially asymmetric but radially symmetric mild stenosis in the annular region of an inclined tapered artery and a co-axial catheter in a suitable flow geometry has been considered to investigate the influence of velocity slip at the stenotic wall as well as hematocrit, shape parameter. The model also includes the tapering effect and inclination of the artery. Expressions for the flow variables have been derived analytically and their variations with various flow parameters are represented graphically. The results for the different values of the parameters involved show that the impedance to flow increases with stenosis height, hematocrit and catheter radius. However, it decreases with the shape parameter, angle of inclination of artery and velocity slip at the stenotic wall. The present analysis is an extension of the work by Chakraborty et al. (2011) and also includes several theoretical models of arterial stenosis in the uniform, tapering and catheterized tubes, with the consideration of velocity slip or zero slip at the vessel wall. Finally, some biological implications of this theoretical modeling are included in brief
Gaussian Copula Mixed Models with Non-Ignorable Missing Outcomes
Get PDFThis paper is concerned with the analysis of mixed data with ordinal and continuous outcomes with the possibility of non - ignorable missing outcomes . A copula-based regression model is proposed that accounts for associations between ordinal and continuous outcomes . Our approach entails specifying underlying latent variables for the mixed outcomes to indicate the latent mechanisms which generate the ordinal and continuous variables . Maximum likelihood estimation of our model parameters is implemented using standard software such as function nlminb in R . Results of simulations concern the relative biases of parameter estimates of joint and marginal models using data with non-ignorable outcomes . The proposed methodology is illustrated using a medical data obtained from an observational study on women with three correlated responses , an ordinal response of osteoporosis of the spine and two continuous responses of body mass index and waistline . The effect of the amount of total body calcium (Ca) , job status (Job) , type of dwelling (Ta) and age on all responses are investigated simultaneously