Microstructures and Strengths of Metals and Ceramics made by Photopolymerbased Rapid Prototyping

Metal and ceramic flexure specimens were fabricated using a photopolymer-based rapid prototyping technique. Photosensitive resins (inks) were produced by dispersing 50 - 55 vol% metal or ceramic powders in a photopolymer resin. Laminates 0.2" thick were built up by repeated application oflayers 3 - 10 mils thick followed by curing under a UV flood lamp with photomasks. The layered samples were thermally processed to remove the photopolymer binder and sintered to high density. Densities, microstructural characterization and flexure strengths are reported for silicon nitride, alumina, zirconia, stainless steel, and tungsten.Mechanical Engineerin

Laminated Object Manufacturing of Si3N4 With Enhanced Properties

The potential to fabricate near net-shape ceramic components of intricate shape is attractive and offers considerable savings in cost and time. The laminated architecture inherent in many Rapid Prototyping techniques can be utilized to enhance material properties by providing weak interfaces at regular intervals, oriented microstructures, and functionally graded compositions. By design and control of these variables it is possible to enhance the strength, toughness and performance of components fabricated from structural ceramics. A range of oriented microstructural features have been investigated in Laminated Object Manufacturing of Si3N4 materials. Changes in the mechanical properties can be related to specific architectures and microstructural developments which took place during sintering.Mechanical Engineerin

Global Analysis of the Evolution and Mechanism of Echinocandin Resistance in Candida glabrata

The evolution of drug resistance has a profound impact on human health. Candida glabrata is a leading human fungal pathogen that can rapidly evolve resistance to echinocandins, which target cell wall biosynthesis and are front-line therapeutics for Candida infections. Here, we provide the first global analysis of mutations accompanying the evolution of fungal drug resistance in a human host utilizing a series of C. glabrata isolates that evolved echinocandin resistance in a patient treated with the echinocandin caspofungin for recurring bloodstream candidemia. Whole genome sequencing identified a mutation in the drug target, FKS2, accompanying a major resistance increase, and 8 additional non-synonymous mutations. The FKS2-T1987C mutation was sufficient for echinocandin resistance, and associated with a fitness cost that was mitigated with further evolution, observed in vitro and in a murine model of systemic candidemia. A CDC6-A511G(K171E) mutation acquired before FKS2-T1987C(S663P), conferred a small resistance increase. Elevated dosage of CDC55, which acquired a C463T(P155S) mutation after FKS2-T1987C(S663P), ameliorated fitness. To discover strategies to abrogate echinocandin resistance, we focused on the molecular chaperone Hsp90 and downstream effector calcineurin. Genetic or pharmacological compromise of Hsp90 or calcineurin function reduced basal tolerance and resistance. Hsp90 and calcineurin were required for caspofungin-dependent FKS2 induction, providing a mechanism governing echinocandin resistance. A mitochondrial respiration-defective petite mutant in the series revealed that the petite phenotype does not confer echinocandin resistance, but renders strains refractory to synergy between echinocandins and Hsp90 or calcineurin inhibitors. The kidneys of mice infected with the petite mutant were sterile, while those infected with the HSP90-repressible strain had reduced fungal burden. We provide the first global view of mutations accompanying the evolution of fungal drug resistance in a human host, implicate the premier compensatory mutation mitigating the cost of echinocandin resistance, and suggest a new mechanism of echinocandin resistance with broad therapeutic potential

Migration to western industrialised countries and perinatal health: A systematic review

Influxes of migrant women of childbearing age to receiving countries have made their perinatal health status a key priority for many governments. The international research collaboration Reproductive Outcomes And Migration (ROAM) reviewed published studies to assess whether migrants in western industrialised countries have consistently poorer perinatal health than receiving-country women. A systematic review of literature from Medline, Health Star, Embase and PsychInfo from 1995 to 2008 included studies of migrant women/infants related to pregnancy or birth. Studies were excluded if there was no cross-border movement or comparison group or if the receiving country was not western and industrialised. Studies were assessed for quality, analysed descriptively and meta-analysed when possible. We identified 133 reports (>20,000,000 migrants), only 23 of which could be meta-analysed. Migrants were described primarily by geographic origin; other relevant aspects (e.g., time in country, language fluency) were rarely studied. Migrants' results for preterm birth, low birthweight and health-promoting behaviour were as good or better as those for receiving-country women in >=50% of all studies. Meta-analyses found that Asian, North African and sub-Saharan African migrants were at greater risk of feto-infant mortality than 'majority' receiving populations, and Asian and sub-Saharan African migrants at greater risk of preterm birth. The migration literature is extensive, but the heterogeneity of the study designs and definitions of migrants limits the conclusions that can be drawn. Research that uses clear, specific migrant definitions, adjusts for relevant risk factors and includes other aspects of migrant experience is needed to confirm and understand these associations.Emigration and immigration Women Perinatal health Refugee Review

The European perinatal health report: Delivering comparable data for examining differences in maternal and infant health

In December 2008, the first-ever European Perinatal Health Report was released by EURO-PERISTAT. Part of the EU Health Programme for health surveillance and reporting, this landmark report presents indicators of perinatal health and care derived from routine statistical data in 25 EU Member States and Norway. It also includes chapters from three other European projects with perinatal data: SCPE on cerebral palsy, EUROCAT on congenital anomalies and EURONEOSTAT on very preterm babies admitted to intensive care. © 2009 Elsevier Ireland Ltd. All rights reserved

Satellite Modular and Reconfigurable Thermal System (SMARTS)

This paper describes a two-phase heat transfer based thermal design architecture for satellites that need to be conceived, configured, launched, and operationally deployed very quickly. The architecture has been given the acronym SMARTS for Satellite Modular and Reconfigurable Thermal System. SMARTS is a Phase I-II SBIR program awarded by the Air Force Research Laboratory, Space Vehicles Directorate to Technology Assessment & Transfer. The SMARTS philosophy involves four basic design rules: (1) modest radiator oversizing; (2) maximum external insulation; (3) internal isothermalization; and (4) radiator heat-flow modulation. For a prototypical multipanel small satellite, the paper describes a SMARTS thermal control system that uses: (a) panel-to-panel heat conduction; (b) intra-panel heat pipe isothermalization; (c) radiator heat-flow modulation via a thermoelectric cooler (TEC) cold-biased loop heat pipe (LHP); and (d) maximum external MLAnalyses are presented that compare the traditional cold-biasing plus heater power passive thermal design approach to the SMARTS approach. Additional analyses and conceptual design work oriented towards the Phase II goal of developing a multi-panel, TEC-coldbiased, LHP-modulated SMARTS small satellite test bed are also described. The ultimate goal is to incorporate SMARTS into the design of future satellites envisioned by the Operationally Responsive Space (ORS) initiative