202 research outputs found

    LDEF materials data bases

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    The Long Duration Exposure Facility (LDEF) and the accompanying experiments were composed of and contained a wide variety of materials representing the largest collection of materials flown in low Earth orbit (LEO) and retrieved for ground based analysis to date. The results and implications of the mechanical, thermal, optical, and electrical data from these materials are the foundation on which future LEO space missions will be built. The LDEF Materials Special Investigation Group (MSIG) has been charged with establishing and developing data bases to document these materials and their performance to assure not only that the data are archived for future generations but also that the data are available to the spacecraft user community in an easily accessed, user-friendly form. This paper discusses the format and content of the three data bases developed or being developed to accomplish this task. The hardware and software requirements for each of these three data bases are discussed along with current availability of the data bases. This paper also serves as a user's guide to the MAPTIS LDEF Materials Data Base

    An overview of NASA testing requirements for alternate cleaning solvents used in liquid and gaseous oxygen environments

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    The elimination of CFC-containing cleaning solvents for oxygen systems has prompted the development of a number of alternative cleaning solvents that must now be evaluated not only for cleanability, but compatibility as well. NASA Handbook 8060.1(NHB 8060.1) establishes the requirements for evaluation, testing, and selection of materials for use in oxygen rich environments. Materials intended for use in space vehicles, specified test facilities, and ground support equipment must meet the requirements of this document. In addition to the requirements of NHB 8060.1 for oxygen service, alternative cleaning solvents must also be evaluated in other areas (such as corrosivity, non-metals compatibility, non-volatile residue contamination, etc.). This paper will discuss the testing requirements of NHB 8060.1 and present preliminary results from early screening tests performed at Marshall Space Flight Center's Materials Combustion Research Facility

    ORGANIC MATTER EXTRACTS OF LITTER AND SOIL: INVOLVEMENT OF ATP SULPHURYLASE

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    Summary-Organic matter extracts from the 01, 02 and A'l horizons of a hardwood forest rapidly incorporated [ 35 S]sulphate into organic sulphur components larger than 12,000 daltons in molecular weight. In the 02 layer extract, the 35 S-label was incorporated into ammo acid-S, sulphonaterS and ester sulphate linkages. This process was stimulated by adenosine 5'-triphosphate (ATP), cellulose, cellobiose, glucose, succinate and pyruvate. The involvement of ATP sulphurylase, elaborated by bacteria present in this extract, is suggested by observations that incorporation was also stimulated by Mg 2+ and inhibited by erythromycin, tetracycline, sodium azide, selenate, molybdate and chlorate. 35 S-labelled adenosine 5'-phosphosulphate (APS) or S'-phosphoadenosine-S'-phosphosulphate (PAPS) also served as S donors for organic-S formation but the rate of organic-S formation was much lower than that observed when [ 35 S]sulphate was the S donor

    Impact of socioeconomic deprivation on rate and cause of death in severe mental illness

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    Background: Socioeconomic status has important associations with disease-specific mortality in the general population. Although individuals with Severe Mental Illnesses (SMI) experience significant premature mortality, the relationship between socioeconomic status and mortality in this group remains under investigated.<p></p> Aims: To assess the impact of socioeconomic status on rate and cause of death in individuals with SMI (schizophrenia and bipolar disorder) relative to the local (Glasgow) and wider (Scottish) populations.<p></p> Methods: Cause and age of death during 2006-2010 inclusive for individuals with schizophrenia or bipolar disorder registered on the Glasgow Psychosis Clinical Information System (PsyCIS) were obtained by linkage to the Scottish General Register Office (GRO). Rate and cause of death by socioeconomic status, measured by Scottish Index of Multiple Deprivation (SIMD), were compared to the Glasgow and Scottish populations.<p></p> Results: Death rates were higher in people with SMI across all socioeconomic quintiles compared to the Glasgow and Scottish populations, and persisted when suicide was excluded. Differences were largest in the most deprived quintile (794.6 per 10,000 population vs. 274.7 and 252.4 for Glasgow and Scotland respectively). Cause of death varied by socioeconomic status. For those living in the most deprived quintile, higher drug-related deaths occurred in those with SMI compared to local Glasgow and wider Scottish population rates (12.3% vs. 5.9%, p = <0.001 and 5.1% p = 0.002 respectively). A lower proportion of deaths due to cancer in those with SMI living in the most deprived quintile were also observed, relative to the local Glasgow and wider Scottish populations (12.3% vs. 25.1% p = 0.013 and 26.3% p = <0.001). The proportion of suicides was significantly higher in those with SMI living in the more affluent quintiles relative to Glasgow and Scotland (54.6% vs. 5.8%, p = <0.001 and 5.5%, p = <0.001). Discussion and conclusions: Excess mortality in those with SMI occurred across all socioeconomic quintiles compared to the Glasgow and Scottish populations but was most marked in the most deprived quintiles when suicide was excluded as a cause of death. Further work assessing the impact of socioeconomic status on specific causes of premature mortality in SMI is needed

    Health care costs, utilization and patterns of care following Lyme disease

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    BACKGROUND:Lyme disease is the most frequently reported vector borne infection in the United States. The Centers for Disease Control have estimated that approximately 10% to 20% of individuals may experience Post-Treatment Lyme Disease Syndrome - a set of symptoms including fatigue, musculoskeletal pain, and neurocognitive complaints that persist after initial antibiotic treatment of Lyme disease. Little is known about the impact of Lyme disease or post-treatment Lyme disease symptoms (PTLDS) on health care costs and utilization in the United States. OBJECTIVES:1) to examine the impact of Lyme disease on health care costs and utilization, 2) to understand the relationship between Lyme disease and the probability of developing PTLDS, 3) to understand how PTLDS may impact health care costs and utilization. METHODS:This study utilizes retrospective data on medical claims and member enrollment for persons aged 0-64 years who were enrolled in commercial health insurance plans in the United States between 2006-2010. 52,795 individuals treated for Lyme disease were compared to 263,975 matched controls with no evidence of Lyme disease exposure. RESULTS:Lyme disease is associated with 2,968highertotalhealthcarecosts(952,968 higher total health care costs (95% CI: 2,807-3,128, p<.001) and 87% more outpatient visits (95% CI: 86%-89%, p<.001) over a 12-month period, and is associated with 4.77 times greater odds of having any PTLDS-related diagnosis, as compared to controls (95% CI: 4.67-4.87, p<.001). Among those with Lyme disease, having one or more PTLDS-related diagnosis is associated with 3,798 higher total health care costs (95% CI: 3,542-4,055, p<.001) and 66% more outpatient visits (95% CI: 64%-69%, p<.001) over a 12-month period, relative to those with no PTLDS-related diagnoses. CONCLUSIONS:Lyme disease is associated with increased costs above what would be expected for an easy to treat infection. The presence of PTLDS-related diagnoses after treatment is associated with significant health care costs and utilization

    Neuroserpin polymorphisms and stroke risk in a biracial population: the stroke prevention in young women study

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    <p>Abstract</p> <p>Background</p> <p>Neuroserpin, primarily localized to CNS neurons, inhibits the adverse effects of tissue-type plasminogen activator (tPA) on the neurovascular unit and has neuroprotective effects in animal models of ischemic stroke. We sought to evaluate the association of neuroserpin polymorphisms with risk for ischemic stroke among young women.</p> <p>Methods</p> <p>A population-based case-control study of stroke among women aged 15–49 identified 224 cases of first ischemic stroke (47.3% African-American) and 211 age-matched control subjects (43.1% African-American). Neuroserpin single nucleotide polymorphisms (SNPs) chosen through HapMap were genotyped in the study population and assessed for association with stroke.</p> <p>Results</p> <p>Of the five SNPs analyzed, the A allele (frequency; Caucasian = 0.56, African-American = 0.42) of SNP rs6797312 located in intron 1 was associated with stroke in an age-adjusted dominant model (AA and AT vs. TT) among Caucasians (OR = 2.05, p = 0.023) but not African-Americans (OR = 0.71, p = 0.387). Models adjusting for other risk factors strengthened the association. Race-specific haplotype analyses, inclusive of SNP rs6797312, again demonstrated significant associations with stroke among Caucasians only.</p> <p>Conclusion</p> <p>This study provides the first evidence that neuroserpin is associated with early-onset ischemic stroke among Caucasian women.</p
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