219 research outputs found

    Prediction Model for the Life of Nickel-cadmium Batteries in Geosynchronous Orbit Satellites

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    A mathematical model is described which predicts the service life of nickel-cadmium batteries designed for geosynchronous orbit satellites. Regression analysis technique is used to analyze orbital data on second generation trickle charged batteries. The model gives average cell voltage as a function of design parameters, operating parameters and time. The voltage model has the properties of providing a good fit to the data, good predictive capability, and agreement with known battery performance characteristics. Average cell voltage can be predicted to within 0.02 volts for up to 8 years. This modeling shows that these batteries will operate reliably for 10 years. Third-generation batteries are expected to operate even longer

    AUSSAT battery life test program

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    AUSSAT Pty. Ltd., the Australian National Satellite organization, has contracted with the Hughes Aircraft Company (HAC) for the construction of 3 satellites based on the now familiar HS-376 product line. As part of the AUSSAT contract, HAC is conducting an extensive NiCd battery life test program. The life test program, objectives and test results to date are described. Particular emphasis is given to the evaluation of the FS2117 separator as a future replacement for the Pellon 2505 separator of which only a very limited quantity remains

    Relevance of cyclin D1b expression and CCND1 polymorphism in the pathogenesis of multiple myeloma and mantle cell lymphoma

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    BACKGROUND: The CCND1 gene generates two mRNAs (cyclin D1a and D1b) through an alternative splicing at the site of a common A/G polymorphism. Cyclin D1a and b proteins differ in their C-terminus, a region involved in protein degradation and sub-cellular localization. Recent data have suggested that cyclin D1b could be a nuclear oncogene. The presence of cyclin D1b mRNA and protein has been studied in two hemopathies in which cyclin D1 could be present: multiple myeloma (MM) and mantle cell lymphoma (MCL). The A/G polymorphism of CCND1 has also been verified in a series of patients. METHODS: The expression of cyclin D1 mRNA isoforms has been studied by real-time quantitative PCR; protein isoforms expression, localization and degradation by western blotting. The CCND1 polymorphism was analyzed after sequencing genomic DNA. RESULTS: Cyclin D1 mRNA isoforms a and b were expressed in mantle cell lymphoma (MCL) and multiple myeloma (MM). Cyclin D1b proteins were present in MCL, rarely in MM. Importantly, both protein isoforms localized the nuclear and cytoplasmic compartments. They displayed the same short half-life. Thus, the two properties of cyclin D1b recognized as necessary for its transforming activity are missing in MCL. Moreover, CCND1 polymorphism at the exon/intron boundary had no influence on splicing regulation in MCL cells. CONCLUSION: Our results support the notion that cyclin D1b is not crucial for the pathogenesis of MCL and MM

    Clinical Outcomes in Persons Coinfected With Human Immunodeficiency Virus and Hepatitis C Virus: Impact of Hepatitis C Virus Treatment

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    Background: A hepatitis C (HCV) cure is associated with changes in lipids and inflammatory biomarkers, but its impact on clinical endpoints among treated human immunodeficiency virus (HIV)/HCV coinfected persons is unclear. / Methods: People living with HIV from EuroSIDA with a known HCV status after January 2001 were classified into strata based on time-updated HCV RNA measurements and HCV treatment, as either HCV antibody–negative; spontaneously resolved HCV; chronic, untreated HCV; cured HCV (HCV RNA–negative); or HCV treatment failures (HCV RNA–positive). Poisson regression was used to compare incidence rates between HCV groups for end-stage liver disease (ESLD; including hepatocellular carcinoma [HCC]), non–acquired immunodeficiency virus defining malignancy (NADM; excluding HCC), and cardiovascular disease (CVD). / Results: There were 16 618 persons included (median follow-up 8.3 years, interquartile range 3.1–13.7). There were 887 CVD, 902 NADM, and 436 ESLD events; crude incidence rates/1000 person-years follow-up were 6.4 (95% confidence interval [CI] 6.0–6.9) for CVD, 6.5 (95% CI 6.1–6.9) for NADM, and 3.1 (95% CI 2.8–3.4) for ESLD. After adjustment, there were no differences in incidence rates of NADM or CVD across the 5 groups. HCV-negative individuals (adjusted incidence rate ratio [aIRR] 0.22, 95% CI 0.14–0.34) and those with spontaneous clearance (aIRR 0.61, 95% CI 0.36–1.02) had reduced rates of ESLD compared to cured individuals. Persons with chronic, untreated HCV infections (aIRR 1.47, 95% CI 1.02–2.13) or treatment failure (aIRR 1.80, 95% CI 1.22–2.66) had significantly raised rates of ESLD, compared to those who were cured. / Conclusions: Incidences of NADM or CVD were independent of HCV group, whereas those cured had substantially lower incidences of ESLD, underlining the importance of successful HCV treatment for reducing ESLD

    Urban Biodiversity, City-Dwellers and Conservation: How Does an Outdoor Activity Day Affect the Human-Nature Relationship?

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    Urban conservation education programs aim to increase knowledge and awareness towards biodiversity and to change attitudes and behaviour towards the environment. However, to date, few urban conservation education studies have evaluated to what extent these programs have managed to achieve their goals. In this study, we experimentally explored the influence of an urban conservation activity day on individual knowledge, awareness and actions towards biodiversity, in both the short and longer term

    Correlation of cutaneous tension distribution and tissue oxygenation with acute external tissue expansion

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    Today, the biomechanical fundamentals of skin expansion are based on viscoelastic models of the skin. Although many studies have been conducted in vitro, analyses performed in vivo are rare. Here, we present in vivo measurements of the expansion at the skin surface as well as measurement of the corresponding intracutaneous oxygen partial pressure. In our study the average skin stretching was 24%, with a standard deviation of 11%, excluding age or gender dependency. The measurement of intracutaneous oxygen partial pressure produced strong inter-individual fluctuations, including initial values at the beginning of the measurement, as well as varying individual patient reactions to expansion of the skin. Taken together, we propose that even large defect wounds can be closed successfully using the mass displacement caused by expansion especially in areas where soft, voluminous tissue layers are present
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