The Uptake of Integrated Perinatal Prevention of Mother-to-Child HIV Transmission Programs in Low- and Middle-Income Countries: A Systematic Review

BACKGROUND: The objective of this review was to assess the uptake of WHO recommended integrated perinatal prevention of mother-to-child transmission (PMTCT) of HIV interventions in low- and middle-income countries. METHODS AND FINDINGS: We searched 21 databases for observational studies presenting uptake of integrated PMTCT programs in low- and middle-income countries. Forty-one studies on programs implemented between 1997 and 2006, met inclusion criteria. The proportion of women attending antenatal care who were counseled and who were tested was high; 96% (range 30-100%) and 81% (range 26-100%), respectively. However, the overall median proportion of HIV positive women provided with antiretroviral prophylaxis in antenatal care and attending labor ward was 55% (range 22-99%) and 60% (range 19-100%), respectively. The proportion of women with unknown HIV status, tested for HIV at labor ward was 70%. Overall, 79% (range 44-100%) of infants were tested for HIV and 11% (range 3-18%) of them were HIV positive. We designed two PMTCT cascades using studies with outcomes for all perinatal PMTCT interventions which showed that an estimated 22% of all HIV positive women attending antenatal care and 11% of all HIV positive women delivering at labor ward were not notified about their HIV status and did not participate in PMTCT program. Only 17% of HIV positive antenatal care attendees and their infants are known to have taken antiretroviral prophylaxis. CONCLUSION: The existing evidence provides information only about the initial PMTCT programs which were based on the old WHO PMTCT guidelines. The uptake of counseling and HIV testing among pregnant women attending antenatal care was high, but their retention in PMTCT programs was low. The majority of women in the included studies did not receive ARV prophylaxis in antenatal care; nor did they attend labor ward. More studies evaluating the uptake in current PMTCT programs are urgently needed

Development of biodegradable Mg-1Zn-0.5Sc alloy & Surface treatment through Laser Shock Peening and Evaluation of Microstructure & Property correlation for Orthopedic Implants

Magnesium (Mg) and its alloys are of much interest as promising third-generation bio-materials for bone implant applications; however, challenges remain for the alloy\u27s mechanical integrity and bio-corrosion behaviour. Therefore, appropriate alloying elements and surface-modification techniques are required to overcome these limitations. Zinc (Zn) and Scandium (Sc) elements were found to have good biocompatibility and biodegradability; hence, they were selected as suitable alloying elements for magnesium. This research work aims to enhance the mechanical integrity and bio-corrosion resistance behaviour of a novel Mg-1wt% Zn-0.5wt% Sc cast alloy by laser shock peening surface treatment with multiple passes (LSP-2 Pass and LSP-3 Pass). Based on the characterization studies, LSP induced beneficial compressive residual stress around the surface and sub-surface region of Mg-1Zn-0.5Sc alloy due to severe plastic deformation, which led to grain refinement through the twinning mechanism of the Mg alloy. Also, the dispersion of second-phase particles (β-ScZn) was observed while analysing the XRD profiles. Strain hardening and grain refinement have been attributed to the evolution of structure and texture, which enhanced the strength, ductility, and corrosion resistance of novel Mg-1Zn-0.5Sc alloy compared to the as-cast condition. From in vitro studies, a low rate of corrosion in simulated body fluid, uniform hydroxyapatite layer formation on the surface and less cytotoxic behaviour was observed for the LSP-3 pass Mg-1Zn-0.5Sc alloy, which is suitable for bone implant applications. However, some limitations remain, and challenges need to be addressed. In the LSP-3 pass, Mg material had only a marginal strength and a corrosion rate of cortical bone properties for orthopaedic implant applications. To address these challenges, Mg-1Zn-0.5Sc alloy was developed through thermomechanical processing at various temperatures. During extrusion at 250°C and 350°C, the microstructure and texture evolution of the hot extruded at 350°C alloy exhibited complete dynamic recrystallization, and texture evolved to strong basal plane orientation, influencing an increased strength of 152 MPa, reduced ductility of 10%, and improved corrosion resistance. Moreover, this hot extruded at 350°C processed Mg alloy underwent multipass laser shock peening surface treatment to synergistically enhance its strength and ductility properties via structural and textural evolution. Hence, laser shock peening on this extruded alloy surface leads to further recrystallizations owing to the effect of developed compressive residual stress near the peened surface, resulting in large grain formation. Also, favourable texture evolution of basal and non-basal planes was observed due to this LSP-induced plastic strain, with significant improvement in strength and ductility to 230MPa and 16%, respectively. Biocompatibility analysis shows that both extruded and LSP-treated alloys have uniform bio-friendly hydroxyapatite layer formation and exhibit good cell viability after 72h of incubation. It also shows a reduced corrosion rate compared to the as-cast alloy, which can also harmonize with tissue healing and implant degradation. The extruded Mg alloy was developed through the LSP technique and can be a candidate material for orthopaedic implant application

Impact of variation of size of the initial release mass in the dynamics of landslide generated tsunami

When debris flows, landslides, or any gravitational mass flows hit closed or partially open water sources such as seas, oceans, fjords, hydraulic reservoirs, mountain lakes, bays, and landslide dams, it results in tsunami (impulse water waves) by transforming their impact energy to water body, potentially causing damages of infrastructures and human casualties both near field and the distant coastlines. The intensity of hazard depends on the scale, location and process of the landslide, and also on the reservoir volume and topography that surrounds it. Volume or size of the initial release mass that fails and slides along a slope is one of the dominant factors to determine the degree of splash, propagating speed and the amplitudes of the fluid waves, and potential dam breach or water spill over. Here, we numerically integrate the two-phase mass flow model [Pudasaini S. P., J. Geophysi. Res. 117 (F03010), 2012] for quasi-three-dimensional, high-resolution simulation results with variation of size of the two-phase initial landslide or debris both longitudinally and laterally. In our numerical experimental results, we observe fundamentally different solid and fluid evolution and wave structures in the reservoir. There are also significant differences in the flow dynamics of solid under water for different volumes of the release mass by extending or contracting the base area along downslope and/or cross-slope directions. The simulation results show that tsunami amplitudes and run out extents are rapidly increased when the volume of the initial release mass in the form of a triangular wedge is increased by increasing the base area through the increment of the length and breadth of the release base. This study can be useful to develop and implement tsunami hazard mitigation strategies to enhance public safety and reduce potential loss due to landslide-generated wave hazards. </jats:p