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  • 1975-1979  (4)
  • 1965-1969  (3)
  • 1
    Electronic Resource
    Electronic Resource
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Sociology 1 (1975), S. 363-428 
    ISSN: 0360-0572
    Source: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Topics: Sociology
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 211 (1966), S. 22-23 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] THE extreme difficulties of interstellar space travel are well known1. It is a commonly accepted view that, apart from the technical difficulties involved, the laws of conservation of energy and momentum forbid the visiting of other planetary systems in the human life-span1. This article sets out ...
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-2048
    Keywords: Apical senescence ; Gibberellins ; Photomorphogenesis ; Pisum ; Senescence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In an early-flowering line of pea (G2) apical senescence occurs only in long days (LD), while growth in short days (SD) is indeterminate. In SD, G2 plants are known to produce a graft-transmissible substance which delays apical senescence in related lines that are photoperiod-insensitive with regard to apical senescence. Gibberellic acid (GA3) applied to the apical bud of G2 plants in LD delayed apical senescence indefinitely, while N6-benzyladenine and α-naphthaleneacetic acid were ineffective. Of the gibberellins native to pea, GA9 had no effect whereas GA20 had a moderate senescence-delaying effect. [3H]GA9 metabolism in intact leaves of G2 plants was inhibited by LD and was restored by placing the plants back in SD. Leaves of photoperiod-insensitive lines (I-types) metabolized GA9 readily regardless of photoperiod, but the metabolites differed qualitatively from those in G2 leaves. A polar GA9 metabolite, GAE, was found only in G2 plants in SD. The level of GA-like substances in methanol extracts from G2 plants dropped about 10-fold after the plants were moved from SD to LD; it was restored by transferring the plants back to SD. A polar zone of these GA-like materials co-chromatographed with GAE. It is suggested that a polar gibberellin is synthesized by G2 plants in SD; this gibberellin promotes shoot growth and meristematic activity in the shoot apex, preventing senescence.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-2048
    Keywords: Apical senescence ; Pisum ; Photomorphogenesis ; Grafting ; Growth regulators ; Senescence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Apical senescence in an early flowering line of pea, G2, is greatly delayed by short days. This behavior is controlled by two dominant genes. Apical senescence of ungrafted, insensitive (I) lines is unaffected by photoperiod. When I-type scions with one of the two required genes were grafted onto G2, apical senescence of the I-type was delayed in short days, but not in long days. Flowering of the I-type was unaffected. The apex of the G2 stock was unaffected as well. Apical senescence of an I-type line lacking both photoperiod genes was not delayed when grafted on G2 in short days. It is concluded that G2 plants grown in short days produce a graft-transmissible factor which delays apical senescence of photoperiodically insensitive lines.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Czechoslovak journal of physics 19 (1969), S. 1471-1479 
    ISSN: 1572-9486
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A review of the possibilities for the chemical exploration of the central regions of the Earth is given, making use of the antineutrino flux produced by natural radioactive isotopes.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Nature of the Transition Metal Carbon-σ Bond. III. Phenylethinyl Metal Phthalocyanines of the First Transition SeriesAs well as the reaction of the anionic metal phthalocyanines Li2[MPc] ·6 THF (M = Cr, Ni, Cu, Zn) and Li[MnPc]·6 THF with alkyl iodides and experiments of a normal organylation by carbanionic addition with the metal phthalocyanines CrPcCl and MPc (M = Mn, Fe, Co, Ni, Cu, Zn) are runing by a relative quick electron transfer with no indications for formation of σ-organyl derivatives of the corresponding metal phthalocyanines.But with lithium or sodium phenylacetylide, respectively, the following phenylethinyl complexes could be prepared, whose mode of formation and constitution are discussed including some iron complexes already described in other connection: \documentclass{article}\pagestyle{empty}\begin{document}$$ \begin{array}{*{20}c} {{\rm Li}\left[{\left({{\rm C}_{\rm 6} {\rm H}_{\rm 5} {\rm C}_{\rm 2} } \right)_2 {\rm M}^{{\rm III}} {\rm Pc}} \right] \cdot {\rm xTHF}\left({{\rm M} = {\rm Cr,Co}} \right),} \hfill \\ {{\rm Li}\left[{{\rm C}_{\rm 6} {\rm H}_{\rm 5} {\rm C}_{\rm 2} {\rm M}^{{\rm II}} {\rm Pc}} \right] \cdot 4,5{\rm THF,C}_{\rm 6} {\rm H}_{\rm 5} {\rm C}_{\rm 2} {\rm Co}^{{\rm III}} {\rm Pc} \cdot {\rm 0,5THF,}} \hfill \\ {{\rm Li}_{\rm 2} \left[{{\rm C}_{\rm 6} {\rm H}_{\rm 5} {\rm C}_{\rm 2} {\rm Co}^{{\rm II}} {\rm Pc}} \right]_2 \cdot 8{\rm THF,Na}\left[{{\rm C}_{\rm 6} {\rm H}_{\rm 5} {\rm C}_{\rm 2} {\rm ZnPc}} \right] \cdot 5{\rm THF}} \hfill \\\end{array} $$\end{document}.
    Notes: Sowohl die Umsetzung der anionischen Metallphthalocyanine Li2[MPc] · 6 THF (M = Cr, Ni, Cu, Zn) und Li[MnPc] · 6 THF mit Alkyljodiden als auch Versuche einer normalen Organylierung durch Carbanionen-Addition mit den Metallphthalocyaninen CrPcCl und MPc (M = Mn, Fe, Co, Ni, Cu, Zn) verliefen unter einer relativ schnellen Elektronenübertragung ohne Anzeichen einer Bildung von σ-Organylderivaten der entsprechenden Metallphthalocyanine.Dagegen konnten mit Lithium- bzw. Natriumphenylacetylid die folgenden Phenyläthinyl-Komplexe dargestellt werden, deren Bildungsweise und Konstitution unter Einbeziehung einiger bereits in anderem Zusammenhang beschriebener Eisen-Komplexe zusammenfassend diskutiert wird: \documentclass{article}\pagestyle{empty}\begin{document}$$ \begin{array}{*{20}c} {{\rm Li}\left[{\left({{\rm C}_{\rm 6} {\rm H}_{\rm 5} {\rm C}_{\rm 2} } \right)_2 {\rm M}^{{\rm III}} {\rm Pc}} \right] \cdot {\rm xTHF}\left({{\rm M} = {\rm Cr,Co}} \right),} \hfill \\ {{\rm Li}\left[{{\rm C}_{\rm 6} {\rm H}_{\rm 5} {\rm C}_{\rm 2} {\rm M}^{{\rm II}} {\rm Pc}} \right] \cdot 4,5{\rm THF,C}_{\rm 6} {\rm H}_{\rm 5} {\rm C}_{\rm 2} {\rm Co}^{{\rm III}} {\rm Pc} \cdot {\rm 0,5THF,}} \hfill \\ {{\rm Li}_{\rm 2} \left[{{\rm C}_{\rm 6} {\rm H}_{\rm 5} {\rm C}_{\rm 2} {\rm Co}^{{\rm II}} {\rm Pc}} \right]_2 \cdot 8{\rm THF,Na}\left[{{\rm C}_{\rm 6} {\rm H}_{\rm 5} {\rm C}_{\rm 2} {\rm ZnPc}} \right] \cdot 5{\rm THF}{\rm .}} \hfill \\\end{array} $$\end{document}
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 11 (1969), S. 1135-1156 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The participation of polyketides in the biogenesis of natural products has long been bolstered by chemical analogies. Many isotopic tracer studies have validated the acetate-polymalonate route, via presumptive extended poly-β-carbonyl intermediates, to a variety of fungal metabolites. Though implicit as antibiotic precursors, the ephemeral polyketides have not been isolated, nor perhaps with the exception of acetoacetate, can oligoketides become incorporated intact into secondary metabolites. However, a prototypical oligoketides in its stable lactone form, methyltriacetic lactone (3, 6-dimethyl-l-hydroxy-2-pyrone), has been obtained from the tropolone-producing mold P. Stipitatum. A convenient synthesis of this metabolite, by methylation of triacetic lactone followed by partition chromatographic separation of the resultant positional isomers, has been devised. In an experiment with 14C-formate, it was shown that the hypothetical, enzyme-bound polyketide precursor to methyltriacetic lactone is probably involved in stipitatie arid formation, and that the origin of the “extra” methyl or methyl-derived carbons of both substances arises from the identical “C1” pool. Radioactive tracer experiments concerning the biogenesis of pulvilloric acid, a fairly unstable antibiotic substance produced by P. Pulvillorum, showed that its exocyclic carboxyl is formed following initial methyl transfer, whereas the ring system of the molecule is essentially acetate-polymalonate derived. In order to test the hypothesis that methyl-branched C14 polyketide precursors to pulvilloric acid exist and may become integrated into the fatty acid multienzyme complex, presumptive fatty acid congeners to pulvilloric acid such as. 1-methylmyristie, 4-methyllauric, or 2-methyllauric acids were sought. These substances were, however, absent from the mycelial fatty acid spectrum, as well as from the fatty acid moieties of a crystalline glyceridc mixture obtained from the beer. Alternative approaches to the detection or isolation of polyketides are discussed.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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