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  • Articles: DFG German National Licenses  (12)
  • 1985-1989  (7)
  • 1975-1979  (5)
  • 1900-1904
  • 1987  (4)
  • 1985  (3)
  • 1979  (1)
  • 1976  (4)
Source
  • Articles: DFG German National Licenses  (12)
Material
Years
  • 1985-1989  (7)
  • 1975-1979  (5)
  • 1900-1904
Year
  • 1
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 57 (1985), S. 5279-5286 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have extended the Kobayashi, Sankey, and Dow [Phys. Rev. B 25, 6367 (1982)] theory of deep levels in Hg1−xCdxTe to include (vacancy, impurity) nearest-neighbor pairs. In qualitative agreement with the results obtained by these workers for isolated point defects, we find that the composition dependences (dE/dx) of the defect energy levels associated with such complexes depend on the site occupied by the impurity atom. Furthermore, we find that the composition dependences of some of the defect levels produced by such a complex are very different than the dE/dx of levels associated with the corresponding isolated point defects. We thus suggest that this theory can often be used as an aid in the identification of the defect center producing an observed energy level. In particular, it can be used to obtain site information about an observed level and, in favorable cases, to distinguish between levels produced by isolated point defects and those produced by complexes. As an example, we compare our theoretical predictions for the dE/dx of levels associated with (vacancy, impurity) pairs to the experimental slopes of the energy levels observed in deep level transient spectroscopy by Jones, Nair, and Polla [Appl. Phys. Lett. 39, 248 (1981)] and find that the theory lends support to these workers' interpretation of their data. In addition, we present new photoluminescence data on both a previously observed and identified acceptor and on an unknown center in Hg1−xCdxTe. As a further example of the usefulness of our theory, we compare the theoretical slopes of energy levels associated with (vacancy, impurity) pairs with the composition dependences of the defect levels extracted from the photoluminescence data. The results of both of the theoretical-experimental comparisons show that the theory can be used successfully, in conjunction with experimental data, to aid in the identification of the defect center which produces an observed energy level.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Allergy 42 (1987), S. 0 
    ISSN: 1398-9995
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Loratadine is a new non-sedating antihistamine. The present studies compared loratadine and terfenadine, another non-sedating antihistamine, for their ability to inhibit the bronchial response to histamine and other autacoids which have been implicated as contributing to the symptoms of an allergic reaction. In addition, the two antihistamines were evaluated in models of immunologically mediated allergic reactions. Loratadine is a more potent inhibitor of histamine-induced bronchospasm in guinea pigs than is terfenadine. Both antihistamines exhibit marked antiserotonin activity at doses 10 times their antihistamine ED50 values. In contrast, loratadine and terfenadine produce little or no inhibition of the bronchial responses to methacholine, leukotriene C4 or platelet-activating factor. An allergic bronchospasm in guinea pigs is inhibited by loratadine (ED50= 0.40 mg/kg, p.o.) and terfenadine (ED50= 1.7 mg/kg, p.o.). The bronchospasm associated with allergic anaphylaxis in rats is significantly inhibited by 10 mg/kg, p.o. loratadine and 30 mg/kg, p.o. terfenadine. Loratadine exhibits antiallergy activity in vitro. At micromolar concentrations, loratadine inhibits the release of histamine from Con A and A23187-stimulated rat peritoneal mast cells and the release of histamine and leukotrine C4 from a Con A-stimulated cloned murine mast cell line
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 262 (1976), S. 153-154 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Four strains of A. tumefaciens were examined. Two strains, IIBV7 and C-58, are virulent and have been shown to harbour a large plasmid which is associated in some way with virulence8. The other two strains IIBNV6 and NT1, are avirulent and do not contain the plasmid. Strains C-58 and NT1 are very ...
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 281 (1979), S. 298-299 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] A strain of two-spotted spider mite, Tetranychus urticae Koch, resistant to an organophosphorus (OP) insecticide, was observed to be more susceptible to a synthetic pyrethroid (SP) insecticide than was a strain which had no history of exposure to insecticides. To confirm this observation ...
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1434-601X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The reaction64Ni(36S,34Si)66Zn atE=198 MeV has been used to measure the mass excess of34Si; a value of −19.971 −0.044 +0.037 MeV was obtained. This result which is in agreement with the previous value (−19.85±0.30 MeV) is in excellent agreement with recent shell-model mass predictions. The result is discussed within the context of the proposed region of deformation aroundZ=11,N=20.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Entomologia experimentalis et applicata 37 (1985), S. 306-306 
    ISSN: 1570-7458
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Planta 131 (1976), S. 271-274 
    ISSN: 1432-2048
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Quantitative trace-enrichment of cytokinins from a plant source (xylem sap from the Douglasfir, Pseudotsuga menziesii (Mirb.) Franco) has been achieved by adsorption onto octadecyl-silica columns followed by elution with ethanol. Adsorption is rapid and efficient and allows complete recovery of cytokinins at the nanomolar level. Douglas-fir sap contains at least four compounds having cytokinin activity, one of which co-elutes with zeatin and another with ribosylzeatin.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1432-2048
    Keywords: Acer ; Daucus ; Cell culture ; Freeze-fracture (rapid freezing) ; Membrane recycling ; Plasma membrane ; Secretion (vesicle-mediated)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Freeze-fracture electron microscopy of propane-jet-frozen samples has been employed to investigate vesicle-mediated secretion and membrane recycling events in carrot (Daucus carota L.) and sycamore maple (Acer pseudoplatanus L.) suspension-culture cells. Stabilization of the cells by means of ultrarapid freezing has enabled us to preserve the cells in a turgid state and to visualize new intermediate membrane configurations related to these events. Indeed, many of the observed membrane configurations, such as flattened membrane vesicles with slit-shaped membrane fusion sites and horseshoe-shaped membrane infoldings, appear to result from the action of turgor forces on the plasma membrane. Individual cells exhibited great variations in numbers and types of membrane configurations postulated to be related to secretion and membrane-recycling events. In the majority of cells, the different membrane profiles displayed a patchy distribution, and within each patch the membrane configurations tended to be of the same stage. This result indicates that secretory events are triggered in domains measuring from 0.1 to about 10 μm in diameter. Based on an extensive analysis of the different membrane configurations seen in our samples, we have formulated the following model of vesicle-mediated secretion in plant cells: Fusion of a secretory vesicle with the plasma membrane leads to the formation of a single, narrow-necked pore that increases in diameter up to about 60 nm. During discharge, the vesicle is flattened, forming a disc-shaped structure perpendicular to the plane of the plasma membrane. As the vesicle is flattened, the pore is converted to a slit, the maximum length of which coincides with the diameter of the flattened vesicle. The flattened vesicle then tips over and concomitantly the plasma-membrane slit becomes curved into a horseshoe-shaped configuration as it extends along the outer margins of the tipped-over vesicle. Some coated pits are present interspersed between the above-mentioned structures, but their numbers appear insufficient to account for an exclusively endocytotic mechanism of membrane recycling. Instead, our micrographs are more consistent with a mixed mode of recycling of membrane components to the cortical endoplamic reticulum and to Golgi cisternae that involves both internalization of membrane by endocytosis and of individual lippid molecules by unknown mechanisms (lipid exchange proteins?). To this end, overall flattening out of the horseshoe-shaped membrane infoldings is accompanied by a retraction and reduction in size of their central, tongue-like structure.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Mathematical geology 8 (1976), S. 209-214 
    ISSN: 1573-8868
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Mathematics
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Temperatures and temperature gradients for the outer corona are obtained from brightness gradients of EUV lines that were measured with the spectroheliograph on OSO-7. Brightness gradients show considerable deviations from isothermal model calculations that include collisional excitation and photoexcitation. A negative temperature gradient that gives both positive and negative ion abundance gradients appears to be able to account for the discrepancy. For λ284 of Fe xv, perhaps the strongest line from the outer corona, measurements during 1972 appear to be consistent with (i) a temperature near 2.3×106K near the equator at ϱ = 1.3±0.1 solar radii from the solar center; (ii) (ϱ/T) dT/dϱ values near -0.7 that extend from as low as ϱ = 1.2 to about ϱ = 1.8. Temperatures from strong lines of Fe xiv and Fe xvi indicate that variations of about ±0.2×106K exist along lines of sight where emission is appreciable. There appears to be some agreement between these results and temperature measurements from ion abundances in the solar wind and Doppler width of λ5303.
    Type of Medium: Electronic Resource
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