86 research outputs found
Impact of Round-the-Clock, Rapid Oral Fluid HIV Testing of Women in Labor in Rural India
Nitika Pant Pai and colleagues report the results of offering a round-the-clock rapid HIV testing program in a rural labor ward setting in India
Biocomposite films based on κ-carrageenan/locust bean gum blends and clays : physical and antimicrobial properties
The aims of this work were to evaluate the physical and antimicrobial properties of biodegradable films composed of mixtures of κ-carrageenan (κ-car) and locust bean gum (LBG) when organically modified clay Cloisite 30B (C30B) was dispersed in the biopolymer matrix. Film-forming solutions were prepared by adding C30B (ranging from 0 to 16 wt.%) into the κ-car/LBG solution (40/60 wt.%) with 0.3 % (w/v) of glycerol. Barrier properties (water vapour permeability, P vapour; CO2 and O2 permeabilities), mechanical properties (tensile strength, TS, and elongation-at-break, EB) and thermal stability of the resulting films were determined and related with the incorporation of C30B. Also, X-ray diffraction (XRD) was done in order to investigate the effect of C30B in film structure. Antimicrobial effects of these films against Listeria monocytogenes, Escherichia coli and Salmonella enterica were also evaluated. The increase of clay concentration causes a decrease of P vapour (from 5.34 × 10−11 to 3.19 × 10−11 g (m s Pa)−1) and an increase of the CO2 permeability (from 2.26 × 10−14 to 2.91 × 10−14 g (m s Pa)−1) and did not changed significantly the O2 permeability for films with 0 and 16 wt.% C30B, respectively. Films with 16 wt.% clay exhibited the highest values of TS (33.82 MPa) and EB (29.82 %). XRD patterns of the films indicated that a degree of exfoliation is attained depending on clay concentration. κ-car/LBG–C30B films exhibited an inhibitory effect only against L. monocytogenes. κ-car/LBG–C30B composite films are a promising alternative to synthetic films in order to improve the shelf life and safety of food products.J. T. Martins, A. I. Bourbon, A. C. Pinheiro and M. A. Cerqueira gratefully acknowledge the Fundacao para a Ciencia e Tecnologia (FCT, Portugal) for their fellowships (SFRH/BD/32566/2006, SFRH/BD/73178/2010, SFRH/BD/48120/2008 and SFRH/BPD/72753/2010, respectively), and B. W. S. Souza acknowledges the Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES, Brazil)
Tailoring of defect luminescence in CVD grown monolayer MoS2 film
Optical properties of strictly monolayer MoS2 films, which are grown on c-sapphire substrates using microcavity based CVD route, have been investigated by temperature dependent absorption and temperature as well as excitation intensity dependent photoluminescence (PL) spectroscopy. Our study reveals a high intensity broad luminescence band appearing at similar to 1.7 eV along with the usual free exciton/trion peak (similar to 1.86 eV). The investigation furthermore attributes this broad transition to excitons bound to two types of defects, whose binding energies are found to be similar to 11 and similar to 118 meV. Integrated intensity of this feature decreases with the increase in the impinging sulfur flux during growth and by post-growth annealing in sulfur atmosphere suggesting that these defects must be related to sulfur deficiency. Interestingly, exciton-phonon coupling for these defect bound excitons is found to be much stronger than that is associated with free excitons/trions. (C) 2018 Elsevier B.V. All rights reserved
Processing, properties and some novel applications of magnetic nanoparticles
Magnetic nanoparticles have been prepared by various soft chemical methods including self-assembly. The bare or surface-modified particles find applications in areas such as hyperthermia treatment of cancer and magnetic field-assisted radioactive chemical separation. We present here some of the salient features of processing of nanostructured magnetic materials of different sizes and shapes, their properties and some possible applications. The materials studied included metals, metal-ceramic composites, and ferrites
Dense β-SiAlONs consolidated by a modified hydrolysis-assisted solidification route
Dense β-Si4Al2O2N6 materials were fabricated by a modified hydrolysis-assisted solidification (HAS) route from aqueous slurries containing 48-50 vol.% solids, in which 5-22 wt.% of the required α-Al2O3 was replaced by equivalent amounts of unprotected aluminium nitride (AlN) powder to promote consolidation via AlN hydrolysis. A fixed amount (9.37 wt.%) of AlN passivated against hydrolysis with a coating phosphate layer was also added to all the samples consolidated by the modified HAS method. The aqueous slurries were cast in non-porous moulds, allowed to set and dried before sintering at 1675 °C for 4 h. For comparison purposes, ceramics with the same predicted final composition (having 64.33% α-Si3N4, 23.36% α-Al2O3, 9.37% AlN and 7% Y2O3 as starting materials) were also consolidated by a conventional dry-powder pressing (CDPP). The β-Si4Al2O2N6 ceramics consolidated by the modified HAS route exhibited superior outstanding properties (bulk density, apparent porosity, water absorption capacity, hardness and fracture toughness) in comparison to the traditional dry-powder pressing route
Recommended from our members
Impact of round-the-clock, rapid oral fluid HIV testing of women in labor in rural India.
BackgroundTesting pregnant women for HIV at the time of labor and delivery is the last opportunity for prevention of mother-to-child HIV transmission (PMTCT) measures, particularly in settings where women do not receive adequate antenatal care. However, HIV testing and counseling of pregnant women in labor is a challenge, especially in resource-constrained settings. In India, many rural women present for delivery without any prior antenatal care. Those who do get antenatal care are not always tested for HIV, because of deficiencies in the provision of HIV testing and counseling services. In this context, we investigated the impact of introducing round-the-clock, rapid, point-of-care HIV testing and counseling in a busy labor ward at a tertiary care hospital in rural India.Methods and findingsAfter they provided written informed consent, women admitted to the labor ward of a rural teaching hospital in India were offered two rapid tests on oral fluid and finger-stick specimens (OraQuick Rapid HIV-1/HIV-2 tests, OraSure Technologies). Simultaneously, venous blood was drawn for conventional HIV ELISA testing. Western blot tests were performed for confirmatory testing if women were positive by both rapid tests and dual ELISA, or where test results were discordant. Round-the-clock (24 h, 7 d/wk) abbreviated prepartum and extended postpartum counseling sessions were offered as part of the testing strategy. HIV-positive women were administered PMTCT interventions. Of 1,252 eligible women (age range 18 y to 38 y) approached for consent over a 9 mo period in 2006, 1,222 (98%) accepted HIV testing in the labor ward. Of these, 1,003 (82%) women presented with either no reports or incomplete reports of prior HIV testing results at the time of admission to the labor ward. Of 1,222 women, 15 were diagnosed as HIV-positive (on the basis of two rapid tests, dual ELISA and Western blot), yielding a seroprevalence of 1.23% (95% confidence interval [CI] 0.61%-1.8%). Of the 15 HIV test-positive women, four (27%) had presented with reported HIV status, and 11 (73%) new cases of HIV infection were detected due to rapid testing in the labor room. Thus, 11 HIV-positive women received PMTCT interventions on account of round-the-clock rapid HIV testing and counseling in the labor room. While both OraQuick tests (oral and finger-stick) were 100% specific, one false-negative result was documented (with both oral fluid and finger-stick specimens). Of the 15 HIV-infected women who delivered, 13 infants were HIV seronegative at birth and at 1 and 4 mo after delivery; two HIV-positive infants died within a month of delivery.ConclusionsIn a busy rural labor ward setting in India, we demonstrated that it is feasible to introduce a program of round-the-clock rapid HIV testing, including prepartum and extended postpartum counseling sessions. Our data suggest that the availability of round-the-clock rapid HIV testing resulted in successful documentation of HIV serostatus in a large proportion (82%) of rural women who were unaware of their HIV status when admitted to the labor room. In addition, 11 (73%) of a total of 15 HIV-positive women received PMTCT interventions because of round-the-clock rapid testing in the labor ward. These findings are relevant for PMTCT programs in developing countries
- …