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  • 1
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Journal of Insect Physiology 35 (1989), S. 781-785 
    ISSN: 0022-1910
    Keywords: Juvenile hormone ; Supella longipalpa ; corpora allata ; ovarian development
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-136X
    Keywords: Octopamine ; Juvenile hormone ; cAMP ; Cockroach ; Electrophysiology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Juvenile hormone production by the corpora allata of the adult female cockroach, Diploptera punctata, can be modulated by treatment with the biogenic amine, octopamine. Endogenous octopamine has been identified within the CA, using HPLC and electrochemical detection. Treatment with octopamine results in a sinusoidal, dose-dependent inhibition of JH biosynthesis by CA from day 2 virgin females, with maximal inhibition occurring at 10-10 M and 10-4 M. In day 4 and day 8 mated female corpora allata octopamine inhibited JH biosynthesis at 5·10-5 M. Although the elevation of either cAMP or cGMP within the CA is known to be associated with an inhibition of JH biosynthesis, treatment with high concentrations of octopamine results in an increase in the level of cAMP but not cGMP. This effect is both dose- and time-dependent. Octopamine treatment also initiates changes in the passive membrane responses of the CA. Superfusion of CA with octopamine results in a pronounced hyperpolarization of CA cells and an increase in the electrotonic potential (indicative of the degree of electrical coupling between CA cells). This effect could be blocked by the octopamine receptor blocker phentolamine. Treatment with octopamine or phentolamine also blocked the hyperpolarization of CA cells normally associated with electrical stimulation of the axon tracts innervating the CA. We hypothesize that octopamine may be a natural neuromodulator of JH production by CA, regulating ion channels in CA cells themselves as well as release of the inhibitory neuropeptide, allatostatin, from the terminals within the CA.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 22 (1978), S. 2553-2571 
    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: An experimental study was carried out to investigate the influence of molecular weight distribution on stretchability and thread nonuniformity of high-density polyethylene monofilaments. For the study, a melt-spinning/multistage stretching device was constructed, and the monofilaments were extruded first into a quench tank and subsequently stretched twice in an annealing bath. Processing variables investigated were (a) the extrusion temperature, (b) the shear rate in the spinnerette hole, (c) the air-gap distance, (d) the annealing bath temperature, (e) the take-up speed at the first-stage stretching, and (f) the take-up speed at the second-stage stretching. Fiber samples were collected at each stage of stretching, namely, (a) as melt-spun, (b) after the first-stage stretching, and (c) after the second-stage stretching. The maximum stretch rate at which thread breakage occurs was determined at the first-and second-stage stretching in the annealing bath. The melt-spun materials were three different grades of Mitsui Petrochemicals high-density polyethylene and two different grades of Union Carbide high-density polyethylene. Also melt spun were blends of two Mitsui polyethylenes and the two Union Carbide polyethylenes. An attempt was made (a) to correlate stretchability with the molecular weight distribution of the high-density polyethylene; (b) to identify the influence of spinning conditions on stretchability for a given polymer; (c) to correlate the variations of the fiber diameter with the molecular weight distribution and spinning conditions, and (d) to correlate the stretchability of a blend system with blending ratio. tensile properties (the tensile strength at the yield point, tensile elastic modulus, and percent elongation at break) were determined for all fiber samples collected, using the Instron tensile tester. For some fiber samples of special interest, selected on the basis of the spinning experiment results, wide-angle x-ray diffraction measurements were taken to determine the molecular orientation in a filament.
    Additional Material: 19 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 39 (1956), S. 1654-1663 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Auf Grund von neuen Beobachtungen und synthetischen Experimenten wurden für α- und β-Sorigenin aus Rhamnus japonica die modifizierten Strukturformeln I11 und XIIT aufgestellt.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Archives of Insect Biochemistry and Physiology 28 (1995), S. 291-309 
    ISSN: 0739-4462
    Keywords: juvenile hormone ; methoprene ; pyriproxyfen ; fat body ; locust ; binding protein ; receptor ; Chemistry ; Food Science, Agricultural, Medicinal and Pharmaceutical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Juvenile hormone (JH) binding components from the fat body of the African migratory locust were analyzed in a search for a potential nuclear JH receptor. Biosynthetically prepared 10R[3H]JH III gave a high proportion of specific binding to isolated nuclei and extracted proteins; data obtained with the JH analogs, [3H]methoprene and [3H]pyriproxyfen, on the other hand, were obscured by abundant non-specific binding. The vast majority of the high affinity JH III binding activity present in cytosolic and nuclear extracts was due to a high molecular weight JH binding protein (JHBP) which has previously been identified in locust hemolymph. This protein has several chromatographic forms which interfered in the search for a nuclear JH receptor. When specific antiserum was used to remove JHBP from nuclear extracts, a novel JH binding activity (NBP) was detected. NBP could be separated from JHBP by precipitation with ammonium sulfate. NBP displayed a high affinity for JH III (Kd = 0.25 nM) and JH I and JH II competed strongly for JH III binding, whereas methoprene and pyriproxyfen showed apparent competition when present in 1,000-fold excess. NBP was present in nuclear extracts at approximately 25,000 sites per cell; levels were similar in male and female locusts and were not greatly affected by the presence or absence of JH. The characteristics of NPB make it a strong candidate for a nuclear JH receptor. © 1995 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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