7,682 research outputs found

    Mice with low levels of Shc proteins display reduced glycolytic and increased gluconeogenic activities in liver.

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    Shc proteins play a role in energy metabolism through interaction with the insulin receptor. The aim of this study was to determine whether Shc proteins influence liver glycolysis and gluconeogenesis under both fed and fasted states. Decreased glycolytic and increased gluconeogenic and transamination enzyme activities were observed in ShcKO versus WT mice. Levels of key regulatory metabolites, such as fructose-2,6-bisphosphate, matched the activity of metabolic pathways. Protein levels of glycolytic and gluconeogenic enzymes were not different. pAMPK protein levels increased with fasting and were higher in ShcKO versus WT mice. Therefore, Shc proteins play a role in shifting the metabolism from glucose oxidation to gluconeogenesis and lipid catabolism and should be considered as regulators of fuel selection. Fuel selection and utilization could play a critical role in healthy aging. Characterization of metabolic events in ShcKO mice would help to elucidate how metabolism is influenced by these proteins

    An assessment of the risk arising from electrical effects associated with carbon fibers released from commercial aircraft fires

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    The risks associated with electrical effects arising from carbon fibers released from commercial aviation aircraft fires were estimated for 1993. The expected annual losses were estimated to be about 470(1977dollars)in1993.Thechancesoftotallossesfromelectricaleffectsexceeding470 (1977 dollars) in 1993. The chances of total losses from electrical effects exceeding 100,000 (1977 dollars) in 1993 were established to be about one in ten thousand

    Conflict, health care and professional perseverance: a qualitative study in the West Bank

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    The past three decades have been a time of considerable global conflict, affecting over 50 countries and causing substantial impacts on civilian health. While many effects are direct results of violence, conflict also impinges on health through indirect means. The restricted mobility of health care staff and patients, targeting of health care workers, and stressful working conditions disrupt the ability of health care workers in conflict zones to function effectively. This paper explores the challenges experienced by health care workers in West Bank, Palestine, as well as their strategies of persistence. Research activities included participant observation and interviews with health care providers, which were then analysed for common themes. Results demonstrated that the Israeli military occupation of the West Bank considerably impacts civilians’ access to both urgent and preventive care. While attempting to deliver care, providers encountered disruptions, harassment and violence, which interrupted care and contributed to job stress. Professional perseverance was evident, but its influence was limited by enduring constraints. This study thus underscores the importance of accountability to international law regarding the rights of civilians to health care in conflict zones. Health professionals may play a particular role in advocating for just and dignified resolutions to conflicts

    Impedance Matched to Vacuum, Invisible Edge, Diffraction Suppressed Mirror

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    Diffraction suppressed mirrors having an invisible edge are disclosed for incident light at both targeted wavelengths and broadband incident light. The mirrors have a first having at least one discontiguous portion having a plurality of nanostructured apertures. The discontiguous mirror portion impedance matches a relatively high impedance portion of the mirror to a relatively low impedance portion of the mirror, thereby reducing the diffraction edge effect otherwise present in a conventional mirror

    Cryogenic Pupil Alignment Test Architecture for Aberrated Pupil Images

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    A document describes cryogenic test architecture for the James Webb Space Telescope (JWST) integrated science instrument module (ISIM). The ISIM element primarily consists of a mechanical metering structure, three science instruments, and a fine guidance sensor. One of the critical optomechanical alignments is the co-registration of the optical telescope element (OTE) exit pupil with the entrance pupils of the ISIM instruments. The test architecture has been developed to verify that the ISIM element will be properly aligned with the nominal OTE exit pupil when the two elements come together. The architecture measures three of the most critical pupil degrees-of-freedom during optical testing of the ISIM element. The pupil measurement scheme makes use of specularly reflective pupil alignment references located inside the JWST instruments, ground support equipment that contains a pupil imaging module, an OTE simulator, and pupil viewing channels in two of the JWST flight instruments. Pupil alignment references (PARs) are introduced into the instrument, and their reflections are checked using the instrument's mirrors. After the pupil imaging module (PIM) captures a reflected PAR image, the image will be analyzed to determine the relative alignment offset. The instrument pupil alignment preferences are specularly reflective mirrors with non-reflective fiducials, which makes the test architecture feasible. The instrument channels have fairly large fields of view, allowing PAR tip/tilt tolerances on the order of 0.5deg

    Fabrication and Test of an Optical Magnetic Mirror

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    Traditional mirrors at optical wavelengths use thin metalized or dielectric layers of uniform thickness to approximate a perfect electric field boundary condition. The electron gas in such a mirror configuration oscillates in response to the incident photons and subsequently re-emits fields where the propagation and electric field vectors have been inverted and the phase of the incident magnetic field is preserved. We proposed fabrication of sub-wavelength-scale conductive structures that could be used to interact with light at a nano-scale and enable synthesis of the desired perfect magnetic-field boundary condition. In a magnetic mirror, the interaction of light with the nanowires, dielectric layer and ground plate, inverts the magnetic field vector resulting in a zero degree phase shift upon reflection. Geometries such as split ring resonators and sinusoidal conductive strips were shown to demonstrate magnetic mirror behavior in the microwave and then in the visible. Work to design, fabricate and test a magnetic mirror began in 2007 at the NASA Goddard Space Flight Center (GSFC) under an Internal Research and Development (IRAD) award Our initial nanowire geometry was sinusoidal but orthogonally asymmetric in spatial frequency, which allowed clear indications of its behavior by polarization. We report on the fabrication steps and testing of magnetic mirrors using a phase shifting interferometer and the first far-field imaging of an optical magnetic mirror
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