577 research outputs found

    On the pathological character of independent random variables

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    Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mathematics, 1959.Vita.Includes bibliographical references (leaf 20).by Donald George Brennan.Ph.D

    Medical Applications of Aerospace Technology

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    Biomedical Application Teams are funded by the National Aeronautics and Space Administration for the purpose of applying aerospace technology to the solution of significant problems in biomedical research and clinical medicine. The Team at Stanford University Medical School is part of the Division of Cardiology and participates in all phases of the technology transfer process including: identification of significant biomedical problems, matching them with appropriate aerospace solutions, testing the new technology in the laboratory and clinical environment and finally, being the link to the medical device industry for commercially producing the technology. The underlying philosophy and general approach by which aerospace engineering and scientific expertise can be used to solve biomedical instrumentation problems is discussed. The methods by which the Teams accelerate the diffusion of new technology from aerospacerelated research to medical applications are reviewed. Specific examples of successful transfers are presented to illustrate the many phases of the technology transfer process and the need for a multidisciplinary, team approach. Innovative technology derived from aerospace-related research is providing the physician with new and better instrumentation for medical research and patient care

    Rangeways - community based planning for ecologically sustainable land use in the Western Australian goldfields

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    Ways to identity and reconcile opportunities tor different land uses while protecting biologically sensitive areas were researched within the Western Australian rangeland from1995 to 2000. The research was undertaken within a framework of community-based regional planning and was underpinned by policies of ecological sustainable development.The research and community structures arising from the work were collectively named the Rangeways project. The purpose was to resolve land use problems through a structural approach to land use planning and the development of processes rather than to devise \u27The Plan\u27

    Potential use of oxygen as a metabolic biosensor in combination with T2*-weighted MRI to define the ischemic penumbra

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    We describe a novel magnetic resonance imaging technique for detecting metabolism indirectly through changes in oxyhemoglobin:deoxyhemoglobin ratios and T2* signal change during ‘oxygen challenge’ (OC, 5 mins 100% O2). During OC, T2* increase reflects O2 binding to deoxyhemoglobin, which is formed when metabolizing tissues take up oxygen. Here OC has been applied to identify tissue metabolism within the ischemic brain. Permanent middle cerebral artery occlusion was induced in rats. In series 1 scanning (n=5), diffusion-weighted imaging (DWI) was performed, followed by echo-planar T2* acquired during OC and perfusion-weighted imaging (PWI, arterial spin labeling). Oxygen challenge induced a T2* signal increase of 1.8%, 3.7%, and 0.24% in the contralateral cortex, ipsilateral cortex within the PWI/DWI mismatch zone, and ischemic core, respectively. T2* and apparent diffusion coefficient (ADC) map coregistration revealed that the T2* signal increase extended into the ADC lesion (3.4%). In series 2 (n=5), FLASH T2* and ADC maps coregistered with histology revealed a T2* signal increase of 4.9% in the histologically defined border zone (55% normal neuronal morphology, located within the ADC lesion boundary) compared with a 0.7% increase in the cortical ischemic core (92% neuronal ischemic cell change, core ADC lesion). Oxygen challenge has potential clinical utility and, by distinguishing metabolically active and inactive tissues within hypoperfused regions, could provide a more precise assessment of penumbra

    Baseline characteristics and enrichment results from the SONAR trial

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    Aim: The SONAR trial uses an enrichment design based on the individual response to the selective endothelin receptor antagonist atrasentan on efficacy (the degree of the individual response in the urinary albumin‐to‐creatinine ratio [UACR]) and safety/tolerability (signs of sodium retention and acute increases in serum creatinine) to assess the effects of this agent on major renal outcomes. The patient population and enrichment results are described here. Methods: Patients with type 2 diabetes with an estimated glomerular filtration rate (eGFR) within 25 to 75 mL/min/1.73 m2 and UACR between 300 and 5000 mg/g were enrolled. After a run‐in period, eligible patients received 0.75 mg/d of atrasentan for 6 weeks. A total of 2648 responder patients in whom UACR decreased by ≥30% compared to baseline were enrolled, as were 1020 non‐responders with a UACR decrease of <30%. Patients who experienced a weight gain of >3 kg and in whom brain natriuretic peptide exceeded ≥300 pg/mL, or who experienced an increase in serum creatinine >20% (0.5 mg/dL), were not randomized. Results: Baseline characteristics were similar for atrasentan responders and non‐responders. Upon entry to the study, median UACR was 802 mg/g in responders and 920 mg/g in non‐responders. After 6 weeks of treatment with atrasentan, the UACR change in responders was −48.8% (95% CI, −49.8% to −47.9%) and in non‐responders was −1.2% (95% CI, −6.4% to 3.9%). Changes in other renal risk markers were similar between responders and non‐responders except for a marginally greater reduction in systolic blood pressure and eGFR in responders. Conclusions: The enrichment period has successfully identified a population with a profound UACR reduction without clinical signs of sodium retention in whom a large atrasentan effect on clinically important renal outcomes is possible. The SONAR trial aims to establish whether atrasentan confers renal protection

    Mineralogy and Petrology of COMET WILD2 Nucleus Samples

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    The sample return capsule of the Stardust spacecraft will be recovered in northern Utah on January 15, 2006, and under nominal conditions it will be delivered to the new Stardust Curation Laboratory at the Johnson Space Center two days later. Within the first week we plan to begin the harvesting of aerogel cells, and the comet nucleus samples they contain for detailed analysis. By the time of the LPSC meeting we will have been analyzing selected removed grains for more than one month. This presentation will present the first results from the mineralogical and petrological analyses that will have been performed

    Self-interest And Public Interest: The Motivations Of Political Actors

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    Self-Interest and Public Interest in Western Politics showed that the public, politicians, and bureaucrats are often public spirited. But this does not invalidate public-choice theory. Public-choice theory is an ideal type, not a claim that self-interest explains all political behavior. Instead, public-choice theory is useful in creating rules and institutions that guard against the worst case, which would be universal self-interestedness in politics. In contrast, the public-interest hypothesis is neither a comprehensive explanation of political behavior nor a sound basis for institutional design
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