12,451 research outputs found

    Development of a polysilicon process based on chemical vapor deposition, phase 1

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    The development of a dichlorosilane-based reductive chemical vapor deposition process for the production of polycrystalline silicon is discussed. Experimental data indicate that the ease of ignition and explosion severity of dichlorosilane (DCS)/air mixtures is substantially attenuated if the DCS is diluted with hydrogen. Redesign of the process development unit to accommodate safety related information is described. Several different sources of trichlorosilane were used to generate a mixture of redistributed chlorosilanes via Dowex ion exchange resin. The unseparated mixtures were then fed to an experimental reactor in which silicon was deposited and the deposited silicon analyzed for electrically active impurities. At least one trichlorosilane source provided material of requisite purity. Silicon grown in the experimental reactor was converted to single crystal material and solar cells fabricated and tested

    Physical activity : strategies for school communities : based on strategies developed during the Be Active School & Community Project 1995-1998

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    The Be Active School and Community Project (BASC) operated in approximately 30 WA primary and secondary schools each year from August 1995 until December 1998 (three years). BASC was a Healthway funded project, promoting the National Heart Foundation\u27s Be Active Everyday message. Under the direction of a Management Committee, two project officers worked with the broad aim of increasing the physical activity rates of children at school and in the local community

    Genomic variations associated with attenuation in Mycobacterium avium subsp paratuberculosis vaccine strains

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    BACKGROUND: Mycobacterium avium subspecies paratuberculosis (MAP) whole cell vaccines have been widely used tools in the control of Johne's disease in animals despite being unable to provide complete protection. Current vaccine strains derive from stocks created many decades ago; however their genotypes, underlying mechanisms and relative degree of their attenuation are largely unknown. RESULTS: Using mouse virulence studies we confirm that MAP vaccine strains 316 F, II and 2e have diverse but clearly attenuated survival and persistence characteristics compared with wild type strains. Using a pan genomic microarray we characterise the genomic variations in a panel of vaccine strains sourced from stocks spanning over 40 years of maintenance. We describe multiple genomic variations specific for individual vaccine stocks in both deletion (26-32 Kbp) and tandem duplicated (11-40 Kbp) large variable genomic islands and insertion sequence copy numbers. We show individual differences suitable for diagnostic differentiation between vaccine and wild type genotypes and provide evidence for functionality of some of the deleted MAP-specific genes and their possible relation to attenuation. CONCLUSIONS: This study shows how culture environments have influenced MAP genome diversity resulting in large tandem genomic duplications, deletions and transposable element activity. In combination with classical selective systematic subculture this has led to fixation of specific MAP genomic alterations in some vaccine strain lineages which link the resulting attenuated phenotypes with deficiencies in high reactive oxygen species handling

    Quantifying argonaute proteins in and out of GW/P-bodies: Implications in microRNA activities

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    MicroRNAs (miRNAs) are a class of ∼22nt non-coding RNAs that regulate the translational potential and stability of mRNAs. Though constituting only 1-4% of human genes, miRNAs are predicted to regulate more than 60% of all mRNAs. The action of miRNAs is mediated through their associations with Argonaute proteins and mRNA targets. Previous studies indicated that though the majority of Argonaute proteins is diffusely distributed in the cytoplasm, a small fraction is consistently observed to be concentrated in a cytoplasmic compartment called GW/P-bodies. In this chapter, we will provide a quantitative and dynamic view of the subcellular localization of miRNA function, followed by a discussion on the possible roles of PBs in miRNA silencing.National Institutes of Health (U.S.) (Grant R01-CA133404)National Cancer Institute (U.S.) (Grant P01-CA42063)National Cancer Institute (U.S.) (Grant P30-CA14051

    Evaluation of serum NT-pCNP as a diagnostic and prognostic biomarker for sepsis in dogs

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    Background: There is a need for diagnostic biomarkers that can rapidly differentiate dogs with sepsis from dogs with noninfectious forms of systemic inflammatory response syndrome (NSIRS). Objectives: To compare serum NT‐pCNP concentrations among dogs with various forms of sepsis, NSIRS, and healthy controls and to evaluate the use of serum NT‐pCNP for the diagnosis of various forms of sepsis in dogs. Animals: One hundred and twelve dogs including 63 critically ill dogs (sepsis n = 29; NSIRS n = 34) and 49 healthy control dogs. Methods: Prospective clinical investigation. Serum samples were collected for NT‐pCNP measurement from dogs with sepsis or NSIRS within 24 hours of intensive care unit admission or at the time of presentation for healthy dogs. Dogs with sepsis were subclassified based on the anatomic region of infection. Serum NT‐pCNP concentrations were compared among sepsis, NSIRS and healthy groups as well as among sepsis subgroups. The area under the curve (AUC), sensitivity, and specificity for identifying dogs with sepsis were determined. Results: Using a cut‐off value of 10.1 pmol/L, AUC, sensitivity, and specificity of NT‐pCNP for differentiating dogs with sepsis from dogs with NSIRS or healthy control dogs were 0.71 (95% CI, 0.58–0.85), 65.5% (45.7–82.1%), and 89.2% (80.4–94.9%), respectively. Serum NT‐pCNP had poor sensitivity for peritoneal sources of sepsis; AUC [0.92 (0.81–1.0)], sensitivity [94% (71–100%)], and specificity [89% (80–95%)] improved when these dogs were excluded. Serum NT‐pCNP concentration was not associated with survival in the sepsis group. Conclusions and Clinical Importance: Serum NT‐pCNP is a promising diagnostic biomarker for sepsis but is a poor indicator of septic peritonitis

    The Effectiveness Of Repairing Fatigue Damaged 7050 Aluminium Alloy Using Shot Peening

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    Shot peening is an effective life extension surface treatment process. In this study, experiments were performed to investigate whether shot peening could be used to recover the fatigue resistance of aluminium alloy 7050 that has experienced prior fatigue damage. The results showed that shot peening may be used for restoring the original fatigue life of the material, but the effectiveness strongly depends on the amount of prior damage (e.g. the crack depth of any cracks that have already formed) in the material. A numerical model was established and the effect of residual stress was incorporated into the model. The prediction by the model agreed well with the experimental results in terms of trend
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