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  • 1
    Publikationsdatum: 2012-06-15
    Beschreibung: We use measurements from the Lunar Exploration Neutron Detector (LEND) collimated sensors during more than one year of the mapping phase of NASA's Lunar Reconnaissance Orbiter (LRO) mission to make estimates of the epithermal neutron flux within known large Permanently Shadowed Regions (PSRs). These are compared with the local neutron background measured outside PSRs in sunlit regions. Individual and collective analyses of PSR properties have been performed. Only three large PSRs, Shoemaker and Cabeus in the south and Rozhdestvensky U in the north, have been found to manifest significant neutron suppression. All other PSRs have much smaller suppression, only a few percent, if at all. Some even display an excess of neutron emission in comparison to the sunlit vicinity around them. Testing PSRs collectively, we have not found any average suppression for them. Only the group of 18 large PSRs, with area 〉200 km2, show a marginal effect of small average suppression, ∼2%, with low statistical confidence. A ∼2% suppression corresponds to ∼125 ppm of hydrogen taking into account the global neutron suppression near the lunar poles and assuming a homogeneous H distribution in depth in the regolith. This means that all PSRs, except those in Shoemaker, Cabeus and Rozhdestvensky U craters, do not contain any significant amount of hydrogen in comparison with sunlit areas around them at the same latitude.
    Print ISSN: 0148-0227
    Thema: Geologie und Paläontologie , Physik
    Publiziert von Wiley im Namen von American Geophysical Union (AGU).
    Standort Signatur Erwartet Verfügbarkeit
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  • 2
    Publikationsdatum: 2012-06-05
    Beschreibung: The latest neutron spectrometer measurements with the Lunar Exploration Neutron Detector (LEND) onboard the Lunar Reconnaissance Orbiter (LRO) are presented. It covers more than 1 year of mapping phase starting on 15 September 2009. In our analyses we have created global maps showing regional variations in the flux of thermal (energy range  0.5 MeV), and compared these fluxes to variances in soil elemental composition, and with previous results obtained by the Lunar Prospector Neutron Spectrometer (LPNS). We also processed data from LEND collimated detectors and derived a value for the collimated signal of epithermal neutrons based on the comparative analysis with the LEND omnidirectional detectors. Finally, we have compared our final (after the data reduction) global epithermal neutron map with LPNS data.
    Print ISSN: 0148-0227
    Thema: Geologie und Paläontologie , Physik
    Publiziert von Wiley im Namen von American Geophysical Union (AGU).
    Standort Signatur Erwartet Verfügbarkeit
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  • 3
    Publikationsdatum: 2012-07-20
    Beschreibung: Results are presented for the LEND instrument onboard LRO for the detection of local spots of suppression and excess of epithermal neutron emission at the lunar poles. Twelve local Neutron Suppression Regions (NSRs) and Neutron Excess Regions (NERs) are detected. It is shown using the data from the LOLA and Diviner instruments that six NSRs have the empirical property “less local irradiation and lower temperature – fewer local neutrons.” These NSRs may be identified with spots of water-ice rich permafrost on the Moon. It is shown that detected NSRs are include in both permanently shadowed and illuminated areas, and they are not coincident with Permanently Shadowed Regions (PSRs) at the bottom of polar craters, as has been commonly expected before LEND presented neutron data with high spatial resolution.
    Print ISSN: 0148-0227
    Thema: Geologie und Paläontologie , Physik
    Publiziert von Wiley im Namen von American Geophysical Union (AGU).
    Standort Signatur Erwartet Verfügbarkeit
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  • 4
    Publikationsdatum: 2012-03-21
    Beschreibung: Hepatocellular carcinoma (HCC) is the fifth most common cancer worldwide. Despite the prevalence of HCC, there is no effective, systemic treatment. The transcription factor LSF is a promising protein target for chemotherapy; it is highly expressed in HCC patient samples and cell lines, and promotes oncogenesis in rodent xenograft models of HCC. Here, we identify small molecules that effectively inhibit LSF cellular activity. The lead compound, factor quinolinone inhibitor 1 (FQI1), inhibits LSF DNA-binding activity both in vitro, as determined by electrophoretic mobility shift assays, and in cells, as determined by ChIP. Consistent with such inhibition, FQI1 eliminates transcriptional stimulation of LSF-dependent reporter constructs. FQI1 also exhibits antiproliferative activity in multiple cell lines. In LSF-overexpressing cells, including HCC cells, cell death is rapidly induced; however, primary or immortalized hepatocytes are unaffected by treatment with FQI1. The highly concordant structure–activity relationship of a panel of 23 quinolinones strongly suggests that the growth inhibitory activity is due to a single biological target or family. Coupled with the striking agreement between the concentrations required for antiproliferative activity (GI50s) and for inhibition of LSF transactivation (IC50s), we conclude that LSF is the specific biological target of FQIs. Based on these in vitro results, we tested the efficacy of FQI1 in inhibiting HCC tumor growth in a mouse xenograft model. As a single agent, tumor growth was dramatically inhibited with no observable general tissue cytotoxicity. These findings support the further development of LSF inhibitors for cancer chemotherapy.
    Print ISSN: 0027-8424
    Digitale ISSN: 1091-6490
    Thema: Biologie , Medizin , Allgemeine Naturwissenschaft
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  • 5
    Publikationsdatum: 1998-02-28
    Beschreibung: Although in Saccharomyces cerevisiae the initiation of meiotic recombination, as indicated by double-strand break formation, appears to be functionally linked to the initiation of synapsis, meiotic chromosome synapsis in Drosophila females occurs in the absence of meiotic exchange. Electron microscopy of oocytes from females homozygous for either of two meiotic mutants (mei-W68 and mei-P22), which eliminate both meiotic crossing over and gene conversion, revealed normal synaptonemal complex formation. Thus, synapsis in Drosophila is independent of meiotic recombination, consistent with a model in which synapsis is required for the initiation of meiotic recombination. Furthermore, the basic processes of early meiosis may have different functional or temporal relations, or both, in yeast and Drosophila.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉McKim, K S -- Green-Marroquin, B L -- Sekelsky, J J -- Chin, G -- Steinberg, C -- Khodosh, R -- Hawley, R S -- New York, N.Y. -- Science. 1998 Feb 6;279(5352):876-8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Section of Molecular and Cellular Biology, University of California, Davis, CA 95616, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/9452390" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Animals ; Chromosomes/genetics/*physiology/ultrastructure ; Crossing Over, Genetic ; Drosophila melanogaster/genetics/*physiology ; Female ; Gene Conversion ; *Meiosis ; Mutation ; Oocytes/physiology ; *Recombination, Genetic ; Saccharomyces cerevisiae/genetics/physiology ; Sister Chromatid Exchange ; Synaptonemal Complex/*physiology
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
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  • 6
    Publikationsdatum: 2011-12-07
    Beschreibung: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Jasny, Barbara R -- Chin, Gilbert -- Chong, Lisa -- Vignieri, Sacha -- New York, N.Y. -- Science. 2011 Dec 2;334(6060):1225. doi: 10.1126/science.334.6060.1225.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/22144612" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Animals ; Biomedical Research/standards ; Computers ; Humans ; Public Policy ; *Reproducibility of Results ; Research/*standards
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
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  • 7
    Publikationsdatum: 2012-05-19
    Beschreibung: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Riddihough, Guy -- Chin, Gilbert -- Culotta, Elizabeth -- Jasny, Barbara -- Roberts, Leslie -- Vignieri, Sacha -- New York, N.Y. -- Science. 2012 May 18;336(6083):818-9. doi: 10.1126/science.336.6083.818.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/22605744" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): *Conflict (Psychology) ; Group Processes ; Humans ; Mass Behavior ; *Population Groups ; *Social Behavior ; Terrorism ; *Violence ; *Warfare
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
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  • 8
    Publikationsdatum: 1996-11-29
    Beschreibung: Lead-salt tunable diode lasers (TDLs) are the only devices currently available that can generate tunable monochromatic radiation at arbitrary wavelengths between 3 and 30 micrometers and are particularly useful for high-resolution spectroscopy over a wide range of spectral regimes. Detailed observations of TDLs show that the observed instrumental linewidth is actually a temporal average of many narrow (less than 0.5 megahertz) emission "modes." The time scale characteristic of these "modes," which appear to be of relatively constant intensity, is of the order of a microsecond. The laser's behavior is highly suggestive of a chaotic process, that is, seemingly random excursions of a dynamic variable (frequency) within a bounded range. This report shows experimentally that TDL emissions are indeed chaotic. Furthermore, in a simple and robust fashion, this chaotic behavior has been successfully controlled with the use of recent techniques that take advantage of chaos to produce a narrow band laser output.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Chin -- Senesac -- Blass -- Hillman -- New York, N.Y. -- Science. 1996 Nov 29;274(5292):1498-501.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉G. Chin and J. J. Hillman, NASA Goddard Space Flight Center, Laboratory for Extraterrestrial Physics, Greenbelt, MD 20771, USA. L. R. Senesac and W. E. Blass, Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996-1200, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8929404" target="_blank"〉PubMed〈/a〉
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
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  • 9
    Publikationsdatum: 2018-10-18
    Beschreibung: Personal lubricants can increase user satisfaction with male condoms by reducing friction and yielding a slippery sensation. However, lubricants pose disadvantages of dilution in physiologic fluids and sloughing away over repeated articulations. To address these drawbacks, a latex surface modification, which becomes lubricious in the presence of physiologic fluid, has been developed and evaluated. This study assesses (i) the frictional performance of the lubricious coating compared to non-coated latex and latex lubricated by personal lubricant, (ii) the level of agreement between human-perceived slipperiness and machine-measured friction, and (iii) human preference for a hypothetical male condom containing the lubricious coating. Friction coefficient of the lubricious coating was 53% lower than that of non-coated latex and approximately equal to that afforded by personal lubricant. A touch test and survey of a small population sample ( N = 33) revealed a strong correlation ( R 2 = 0.83) between human-perceived slipperiness and machine-measured friction. A majority of participants (73%) expressed a preference for a condom containing the lubricious coating, agreeing that an inherently slippery condom that remained slippery for a long duration would increase their condom usage. Such a coating shows potential to be an effective strategy for decreasing friction-associated pain, increasing user satisfaction and increasing condom usage.
    Schlagwort(e): materials science, biomedical engineering
    Digitale ISSN: 2054-5703
    Thema: Allgemeine Naturwissenschaft
    Publiziert von Royal Society
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  • 10
    Publikationsdatum: 2010-10-23
    Beschreibung: Hydrogen has been inferred to occur in enhanced concentrations within permanently shadowed regions and, hence, the coldest areas of the lunar poles. The Lunar Crater Observation and Sensing Satellite (LCROSS) mission was designed to detect hydrogen-bearing volatiles directly. Neutron flux measurements of the Moon's south polar region from the Lunar Exploration Neutron Detector (LEND) on the Lunar Reconnaissance Orbiter (LRO) spacecraft were used to select the optimal impact site for LCROSS. LEND data show several regions where the epithermal neutron flux from the surface is suppressed, which is indicative of enhanced hydrogen content. These regions are not spatially coincident with permanently shadowed regions of the Moon. The LCROSS impact site inside the Cabeus crater demonstrates the highest hydrogen concentration in the lunar south polar region, corresponding to an estimated content of 0.5 to 4.0% water ice by weight, depending on the thickness of any overlying dry regolith layer. The distribution of hydrogen across the region is consistent with buried water ice from cometary impacts, hydrogen implantation from the solar wind, and/or other as yet unknown sources.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Mitrofanov, I G -- Sanin, A B -- Boynton, W V -- Chin, G -- Garvin, J B -- Golovin, D -- Evans, L G -- Harshman, K -- Kozyrev, A S -- Litvak, M L -- Malakhov, A -- Mazarico, E -- McClanahan, T -- Milikh, G -- Mokrousov, M -- Nandikotkur, G -- Neumann, G A -- Nuzhdin, I -- Sagdeev, R -- Shevchenko, V -- Shvetsov, V -- Smith, D E -- Starr, R -- Tretyakov, V I -- Trombka, J -- Usikov, D -- Varenikov, A -- Vostrukhin, A -- Zuber, M T -- New York, N.Y. -- Science. 2010 Oct 22;330(6003):483-6. doi: 10.1126/science.1185696.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Institute for Space Research of the Russian Academy of Science, 117997 Moscow, Russia. imitrofa@space.ru〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20966247" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Extraterrestrial Environment ; Hydrogen ; *Moon ; Spectrum Analysis
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
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