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  • 1
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    Effects of dimethyl prostaglandin A1 on herpes simplex virus and human immunodeficiency virus replication (1992)
    In:  Other Sources
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    Publication Date: 2011-08-24
    Description: We have investigated the direct effect of dimethyl prostaglandin A1 (dmPGA1) on the replication of herpes simplex virus (HSV) and human immunodeficiency virus type 1 (HIV-1). dmPGA1 significantly inhibited viral replication in both HSV and HIV infection systems at concentrations of dmPGA1 that did not adversely alter cellular DNA synthesis. The 50% inhibitory concentration (ID50) for several HSV type 1 (HSV-1) strains ranged from 3.8 to 5.6 micrograms/ml for Vero cells and from 4.6 to 7.3 micrograms/ml for human foreskin fibroblasts. The ID50s for two HSV-2 strains varied from 3.8 to 4.5 micrograms/ml for Vero cells; the ID50 was 5.7 micrograms/ml for human foreskin fibroblasts. We found that closely related prostaglandins did not have the same effect on the replication of HSV; dmPGE2 and dmPGA2 caused up to a 60% increase in HSV replication compared with that in untreated virus-infected cells. HIV-1 replication in acutely infected T cells (VB line) and chronically infected macrophages was assessed by quantitative decreases in p24 concentration. The effective ID50s were 2.5 micrograms/ml for VB cells acutely infected with HIV-1 and 5.2 micrograms/m for chronically infected macrophages. dmPGA1 has an unusual broad-spectrum antiviral activity against both HSV and HIV-1 in vitro and offers a new class of potential therapeutic agents for in vivo use.
    Keywords: Life Sciences (General)
    Type: Antimicrobial agents and chemotherapy (ISSN 0066-4804); Volume 36; 10; 2253-8
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  • 2
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    Review of the biological effects of weightlessness on the human endocrine system (1993)
    In:  Other Sources
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    Publication Date: 2011-08-24
    Description: Studies from space flights over the past two decades have demonstrated that there are basic physiological changes in humans during space flight. These changes include cephalad fluid shifts, loss of fluid and electrolytes, loss of muscle mass, space motion sickness, anemia, reduced immune response, and loss of calcium and mineralized bone. The cause of most of these manifestations is not known but the general approach has been to investigate systemic and hormonal changes. However, data from the 1973-1974 Skylabs, Spacelab 3 (SL-3), Spacelab D-I (SL-DI), and now the new SLS-1 missions support a more basic biological response to microgravity that may occur at the tissue, cellular, and molecular level. This report summarizes ground-based and SLS-1 experiments that examined the mechanism of loss of red blood cell mass in humans, the loss of bone mass and lowered osteoblast growth under space flight conditions, and loss of immune function in microgravity.
    Keywords: Life Sciences (General)
    Type: Receptor (ISSN 1052-8040); Volume 3; 3; 145-54
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  • 3
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    X-ray spectroscopy of SNR E0102-72 with the ASCA satellite (1994)
    In:  Other Sources
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    Publication Date: 2011-08-24
    Description: The Advanced Satellite for Cosmology and Astrophysics (ASCA) satellite has obtained a moderate-resolution energy spectrum of E0102-72, the brightest Supernova Remnant (SNR) in the Small Magellanic Cloud (SMC). This paper reports on the first results of the analysis of the high quality spectrum of E0102-72. The spectrum shows resolved emission lines of He-like K alpha, H-like K alpha and K beta from oxygen, neon, and magnesium. The intensity ratios of these lines cannot be explained by a multi-component plasma model with uniform abundances, but requires abundance inhomogeneity in the plasma. We demonstrate how the spectral capabilities of the ASCA SIS make available new diagnostics of X-ray plasmas in a state of non-equilibrium ionization. Some interpretation based on the spectral analysis is also given.
    Keywords: ASTROPHYSICS
    Type: PASJ: Publications of the Astronomical Society of Japan (ISSN 0004-6264); 46; 3; p. L121-L124
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  • 4
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    Dayside ionospheric convection changes in response to long-period interplanetary magnetic field oscillations - Determination of the ionospheric phase velocity (1992)
    In:  Other Sources
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    Publication Date: 2011-08-24
    Description: Ground magnetic field perturbations recorded by the CANOPUS magnetometer network in the 7 to 13 MLT sector are used to examine how reconfigurations of the dayside polar ionospheric flow take place in response to north-south changes of the IMF. During the 6-h interval in question, IMF Bz oscillates between +/- 7 nT with about a 1-h period. Corresponding variations in the ground magnetic disturbance are observed which we infer are due to changes in ionospheric flow. Cross correlation of the data obtained from two ground stations at 73.5 deg magnetic latitude, but separated by about 2 hours in MLT, shows that changes in the flow are initiated in the prenoon sector (about 10 MLT) and then spread outward toward dawn and dusk with a phase speed of about 5 km/s over the longitude range about 8 to 12 MLT, slowing to about 2 km/s outside this range. Cross correlating the data from these ground stations with IMP 8 IMF Bz records produces a MLT variation in the ground response delay relative to the IMF which is compatible with these deduced phase speeds.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 97; A12; p. 19,373-19,380.
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  • 5
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    X-ray evidence for particulate contamination on the AXAF VETA-1 mirrors (1993)
    In:  Other Sources
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    Publication Date: 2011-08-24
    Description: X-ray testing of the AXAF outer mirror pairs, in the VETA-1 configuration, reveals a point spread function (PSF) with unexpectedly large wings at low energies. Although the angular dependence in the wings of the PSF is close to that expected for diffractive scattering from surface roughness, the energy dependence differs substantially. Analyses of the observed X-ray PSF, images near ring focus, and single-quadrant images at conjugate focus suggest that the excess scattering observed at low X-ray energies results from diffractive scattering by relatively small grains (as small as a few tenths micrometer in radius). We develop a simple model for the contribution of scattering by particulates to the PSF. Merging this model with that for scattering by surface roughness, we fit the combined model to the observed energy-dependent PSF, in order to estimate parameters and associated uncertainties characterizing the grain-size distribution and the surface-roughness power spectral density. In particular, we find that the fractional coverage of the mirrors by particulates is approximately 1 x 10 exp -4 (for grain radii between 0.1 and 10 microns), and that the rms surface-roughness is approximately 0.7 nm (for spatial frequencies between 1/mm and 1000/mm).
    Keywords: OPTICS
    Type: In: Multilayer and grazing incidence X-ray(EUV optics for astronomy and projection lithography; Proceedings of the Meeting, San Diego, CA, July 19-22, 1992 (A93-39601 15-74); p. 171-182.
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  • 6
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    Calibration of the Energetic Gamma-Ray Experiment Telescope (EGRET) for the Compton Gamma-Ray Observatory (1993)
    In:  Other Sources
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    Publication Date: 2011-08-24
    Description: The calibration of the (EGRET) prior to its launch aboard the Compton Gamma Ray Observatory, the continuing calibration after launch, and instrument-performance results based on calibrations and early postlaunch data, are described. Particular attention is given to the effective area, the annular resolution, and the energy resolution.
    Keywords: SPACECRAFT INSTRUMENTATION
    Type: Astrophysical Journal Supplement Series (ISSN 0067-0049); 86; 2; p. 629-656.
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  • 7
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    A practical approach to determining the uncertainty of a pressure measurement system (1993)
    In:  Other Sources
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    Publication Date: 2011-08-24
    Description: The pressure measurement systems located at three propulsion component test stands at the Marshall Space Flight Center (MSFC) were evaluated for their specific measurement uncertainty levels. An elemental error source evaluation was performed to provide an analytical estimate of uncertainty. Applied loads tests were also conducted at the different MSFC test sites to derive an empirical estimate of uncertainty for the measurement system process. The analytical results are compared to those obtained empirically. The data from MFSC was also compared to data reported from other comparable test facilities. Methods for acquiring and processing the data from calibration, acquisition, and reduction error sources are also addressed.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: In: International Instrumentation Symposium, 39th, Albuquerque, NM, May 2-6, 1993, Proceedings (A93-54351 24-35); p. 511-539.
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  • 8
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    Image analysis of the AXAF VETA-1 X-ray mirror (1993)
    In:  Other Sources
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    Publication Date: 2011-08-24
    Description: Initial core scan data of the VETA-1 X-ray mirror proved disappointing, showing considerable unpredicted image structure and poor measured FWHM. 2-D core scans were performed, providing important insight into the nature of the distortion. Image deconvolutions using a raytraced model PSF was performed successfully to reinforce our conclusion regarding the origin of the astigmatism. A mechanical correction was made to the optical structure, and the minor was tested successfully (FWHM 0.22 arcsec) as a result.
    Keywords: OPTICS
    Type: In: Multilayer and grazing incidence X-ray(EUV optics for astronomy and projection lithography; Proceedings of the Meeting, San Diego, CA, July 19-22, 1992 (A93-39601 15-74); p. 136-151.
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  • 9
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    One joule output from a diode-array-pumped Nd:YAG laser with side-pumped rod geometry (1992)
    In:  Other Sources
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    Publication Date: 2011-08-24
    Description: Output of 1.25 J per pulse (1.064 micron) with an absolute optical efficiency of 28 percent and corresponding electrical efficiency of 10 percent was demonstrated in a diode-array-pumped Nd:YAG laser using a side-pumped rod geometry in a master-oscillator/power-amplifier configuration. In Q-switched operation, an output of 0.75 J in a 17-ns pulse was obtained. The fundamental laser output was frequency doubled in KTP with 60 percent conversion efficiency to obtain 0.45 J in a 16-ns pulse at 532 nm. The output beam had high spatial quality with pointing stability better than 40 microrad and a shot-to-shot pulse energy fluctuation of less than +/-3 percent.
    Keywords: LASERS AND MASERS
    Type: IEEE Journal of Quantum Electronics (ISSN 0018-9197); 28; 4, Ap; 977-985
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  • 10
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    Cytoplasmic pH influences cytoplasmic calcium in MC3T3-E1 osteoblast cells (1993)
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    Publication Date: 2011-08-24
    Description: We found that the cytoplasmic concentration of calcium (Cai) of MC3T3-E1 osteoblasts was influenced by the type of pH buffer we used in the perfusing medium, suggesting that intracellular pH (pHi) might influence Cai. To study this effect, the Cai and pHi were monitored as we applied various experimental conditions known to change pHi. Exposure to NH4Cl caused a transient increase in both pHi and Cai without a change in extracellular pH (pHo). Decreasing pHo and pHi by lowering the bicarbonate concentration of the medium decreased Cai, and increasing pHi by the removal of 5% CO2 increased Cai. Clamping pHi to known values with 10 microM nigericin, a potassium proton ionophore, also influenced Cai: acid pHi lowered Cai, whereas alkaline pHi increased it. The rise in Cai appears to be very sensitive to the extracellular concentration of calcium, suggesting the existence of a pH-sensitive calcium influx mechanism. We conclude that physiologic changes in pH could modulate Cai by controlling the influx of calcium ions and could change the time course of the Cai transient associated with hormonal activation.
    Keywords: Life Sciences (General)
    Type: Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research (ISSN 0884-0431); Volume 8; 6; 725-32
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