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201.
Roger Launius 《Astropolitics》2013,11(3):277-322
The loss of the Space Shuttle Columbia on 1 February 2003 brought to the fore the sad history of the Space Shuttle's origins, evolution, operation, and the continuing challenge of space access. The crisis that emerged in human access to space because of the accident was greater than any experienced since the end of the Apollo program more than thirty years earlier. This essay explores the origins and operations of the Space Shuttle, the varied efforts to build a successor vehicle versus upgrading the shuttle fleet, and suggests that the first decade of the twenty-first century promises to offer both serious challenges and enormous potential for the development of new launch vehicles that may finally achieve the long-held dream of reliable, affordable access to space. The essay ends by asking whether or not the half-hearted quest for a shuttle replacement might not portend the demise human spaceflight for the United States. 相似文献
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Retrospective review of hanging suicides in individuals aged ≤ 17 years was undertaken at Forensic Science South Australia, Australia, over two 5-year periods: 1995-1999 and 2005-2009. Seven cases of hanging suicides were identified from 1995 to 1999, with a further 14 cases from 2005 to 2009, an increase of 100% (p < 0.001). Hanging accounted for 33.3% of all suicides in this age group (7/21) from 1995 to 1999, compared with 93.3% of the total number of suicides (14/15) in the second 5-year period. In contrast, Australian national data from 1998 and 2008 showed a 30% decrease in hanging suicides in the young, from one case/100,000 population in 1998 to 0.7 in 2008. Cluster suicides occur in the young and are often initiated by direct communication. As it is possible that Internet-based social sites may facilitate this phenomenon, investigations should include an evaluation of the victim's Internet access given the potential risk of similar actions by peers. 相似文献
208.
Systemic lupus erythematosus is an autoimmune connective tissue disorder that affects multiple organs. While the clinical manifestations may vary in intensity over time and be associated with chronic disease, occasional cases occur where sudden and unexpected death has occurred. Cardiovascular disease is common, with accelerated atherosclerosis, intravascular thrombosis associated with antiphospholipid syndrome, and hypertensive cardiomegaly. Vasculitis with superimposed thrombosis may result in critical reduction in blood to vital organs, such as the heart and brain with infarction. Mesenteric ischemia may be caused by vasculitis, thrombosis, and accelerated atherosclerosis and may result in lethal intestinal infarction. Other diverse causes of sudden death include myocarditis, epilepsy, pulmonary hypertension, pulmonary thromboembolism, and sepsis. The autopsy evaluation of such cases requires careful examination of all organs with extensive histological sampling to include blood vessels, and microbiological sampling for bacteria, viruses, and fungi. 相似文献
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To determine whether vitreous humor sodium levels might be of use in evaluating deaths associated with immersion, samples of vitreous humor were prospectively evaluated at autopsy over a 4-year period from 2006 to 2009. There were 19 cases of saltwater immersion (age range 9-76 years; mean age 44 years; M:F, 2.8:1) and 16 freshwater immersions (age range 2-81 years; mean age 27 years; M:F, 2.2:1). In the group of saltwater drownings, vitreous humor sodium levels were elevated, ranging from 145 to 184 mM (mean = 160.2 ± 9.9 mM), and in the cases of freshwater drowning, the levels were reduced, ranging from 73 to 148 mM (mean = 129.8 ± 17 mM; p < 0.0001). Alterations in electrolyte levels may have been because of hemoconcentration or dilution from electrolyte fluxes in the lungs, or from passive diffusion during immersion. This study has demonstrated that vitreous sodium level is an easily performed test that may be a useful adjunct to the investigation of possible immersion deaths. 相似文献
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Basal vacuolization of renal tubular epithelial cells (so-called Armanni-Ebstein phenomenon) has been attributed to hyperglycemia causing accumulation of cytoplasmic glycogen. Review of 34 autopsy cases with significant hyperglycemia (vitreous glucose ≥ 15 mmol/L/270 mg/dL) was undertaken to determine whether there was any significant association between the degree of hyperglycemia and the severity of this morphological change (graded as 0, 1+, 2+, and 3+). No association was demonstrated. Review of the subgroup of 14 cases with terminal hyperglycemia without ketoacidosis was then undertaken to assess the effect of hyperglycemia in isolation on renal tubular epithelial cells. Vitreous glucose levels in these 14 cases ranged from 17 to 49.7 mmol/L (306-894.6 mg/dL) with a mean of 26.25 mmol/L (472.5 mg/dL) and β-hydroxybutyrate levels ranged from 0.02 to 2.55 mmol/L (0.36-45.9 mg/dL) with a mean 0.79 mmol/L (14.22 mg/dL). Not one of the latter cases displayed basal vacuolization. No relationship between basal vacuolization of renal tubular epithelial cells at autopsy and terminal hyperglycemia could, therefore, be demonstrated. 相似文献