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  • 1
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Inorganic chemistry 28 (1989), S. 3297-3305 
    ISSN: 1520-510X
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Journal of natural products 46 (1983), S. 350-352 
    ISSN: 1520-6025
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    Global change biology 6 (2000), S. 0 
    ISSN: 1365-2486
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Geography
    Notes: Soil microbial biomass C (Cmic) is a sensitive indicator of trends in organic matter dynamics in terrestrial ecosystems. This study was conducted to determine the effects of tropospheric CO2 or O3 enrichments and moisture variations on total soil organic C (Corg), mineralizable C fraction (CMin), Cmic, maintenance respiratory (qCO2) or Cmic death (qD) quotients, and their relationship with basal respiration (BR) rates and field respiration (FR) fluxes in wheat-soybean agroecosystems. Wheat (Triticum aestivum L.) and soybean (Glycine max. L. Merr) plants were grown to maturity in 3-m dia open-top field chambers and exposed to charcoal-filtered (CF) air at 350 μL CO2 L−1; CF air + 150 μL CO2 L−1; nonfiltered (NF) air + 35 nL O3 L−1; and NF air + 35 nL O3 L−1 + 150 μL CO2 L−1 at optimum (− 0.05 MPa) and restricted soil moisture (− 1.0 ± 0.05 MPa) regimes. The + 150 μL CO2 L−1 additions were 18 h d−1 and the + 35 nL O3 L−1 treatments were 7 h d−1 from April until late October. While Corg did not vary consistently, CMin, Cmic and Cmic fractions increased in soils under tropospheric CO2 enrichment (500 μL CO2 L−1) and decreased under high O3 exposures (55 ± 6 nL O3 L−1 for wheat; 60 ± 5 nL O3 L−1 for soybean) compared to the CF treatments (25 ± 5 nL O3 L−1). The qCO2 or qD quotients of Cmic were also significantly decreased in soils under high CO2 but increased under high O3 exposures compared to the CF control. The BR rates did not vary consistently but they were higher in well-watered soils. The FR fluxes were lower under high O3 exposures compared to soils under the CF control. An increase in Cmic or Cmic fractions and decrease in qCO2 or qD observed under high CO2 treatment suggest that these soils were acting as C sinks whereas, reductions in Cmic or Cmic fractions and increase in qCO2 or qD in soils under elevated tropospheric O3 exposures suggest the soils were serving as a source of CO2.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1573-9325
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Cellular and molecular life sciences 55 (1999), S. 128-130 
    ISSN: 1420-9071
    Keywords: Key words. Ventral neural tube cells; chick embryo; hepatocytes; development; liver.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. A population of ventral neural tube cells has recently been shown to migrate out of the hind brain neural tube via the vagus nerve and contribute to the developing gastrointestinal tract. Since liver is also innervated by the vagus nerve, we sought to determine if these cells also migrate into the liver. Ventral neural tube cells in the caudal hindbrain of chick embryos were tagged with a replication-deficient retroviral vector containing the LacZ gene on embryonic day 2. Embryos were processed for detection of labeled cells on embryonic day 5 and 11. Labeled cells were seen in the liver on both days and identified as hepatocytes. Previously, it was believed that all hepatocytes develop from the gut endoderm. Results of the present study show an additional source for the formation of liver cells.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical crystallography 30 (2000), S. 135-138 
    ISSN: 1572-8854
    Keywords: alkaloid ; tazettine type ; amaryllidaceae ; crystal structure ; molecular mechanics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract The crystal and molecular structure of augustamine (1), C17H19NO4 an amaryllidaceae alkaloid of the tazettine group has been determined by direct methods from single crystal x-ray diffractometer data and refined by full-matrix least squares. The alkaloid (1) crystallizes in the space group P212121, with cell parameters: a = 7.833(8) b = 11.08(2) å, c = 16.69(6) Å, Z = 4, Dc = 1.381 g/cm−3, R = 7.6% for 1115 observed reflections. The molecule, having a hexacyclic ring system, is very rigid with the ring B in a chair conformation. Molecular mechanics calculations have been made using MM3(2000) force field.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Astrophysics and space science 108 (1985), S. 227-236 
    ISSN: 1572-946X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Photoelectric observations of the eclipsing variable β Per, were obtained inUBV standard system, and new elements for the primary minimum were determined as $$J.D. = 2445641.5135,O - C = 0_.^d 0.009.$$ The light curves of the system were analysed using Fourier techniques in the frequency-domain. The fractional radii of both components are $$r_1 = 0.217 \pm 0.002,r_2 = 0.233 \pm 0.002andi = 85.5 \pm 0.5.$$ Absolute elements were derived and the effective temperatures are $$T_1 = 11800K,T_2 = 5140K.$$
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 60 (1996), S. 2165-2176 
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The Concurrent grafting of acrylic acid (AA) and crosslinking of dimethylodihydroxyethyleneurea (DMDHEU) with cotton fabric in the presence of ammonium persulfate [(NH4)2S2O8)], magnesium chloride hexahydrate (MgCl2 · 6H2O), and ammonium chloride (NH4Cl) catalysts were studied. These salts were separately used or as a binary mixture of (NH4)2S2O8/MgCl2 · 6H2O or (NH4)2S2O8/NH4Cl. The pad-dry-cure method was employed for the fabric treatment under a variety of conditions. The latter include the nature and kind of the single catalyst as well as pair-mixed catalysts, the concentrations of the catalyst and AA, and temperature and duration of curing. The effects of these conditions on the values of the carboxyl content and crease recovery angle (CRA) of the treated fabrics were evaluted. The tensile strength, elongation at break, dyeability, aqueous and nonaqueous oily soiling, and soil-release properties of the treated fabrics were also examined. Results obtained indicated that all treated fabrics have superior properties, except tensile strength and elongation at break, as compared with the untreated fabric (control). However, beside the AA-grafting and DMDHEU-crosslinking reactions, there are other types of reactions catalyzed by the salts used, viz., the addition reactions between AA molecules and the cellulosic hydroxyls The tentative mechanisms for these reactions are suggested. © 1996 John Wiley & Sons, Inc.
    Additional Material: 8 Tab.
    Type of Medium: Electronic Resource
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