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  • Polymer and Materials Science  (29)
  • Auxin and stem growth  (2)
  • Life and Medical Sciences  (2)
  • Organic Chemistry  (2)
  • 1
    Electronic Resource
    Electronic Resource
    Indole-3-acetic acid levels after phytochrome-mediated changes in the stem elongation rate of dark- and light-grownPisum seedlings (1992)
    Springer
    Planta 188 (1992), S. 85-92 
    Details
    ISSN: 1432-2048
    Keywords: Auxin and stem growth ; Epidermis and stem growth ; Pisum (stem growth) ; Phytochrome stem growth ; Stem elongation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The effect of red (R) and far-red (FR) light on stem elongation and indole-3-acetic acid (IAA) levels was examined in dwarf and tallPisum sativum L. seedlings. Red light reduced the extension-growth rate of etiolated seedlings by 70–90% after 3 h, and this inhibition was reversible by FR. Inhibition occurred throughout the growing zone. After 3 h of R, the level of extractable IAA in whole stem sections from the growing zone of etiolated plants either increased or showed no change. By contrast, extractable IAA from epidermal peels consistently decreased 3 h after R treatments. Decreases of 40% were observed for epidermal peels from the top 1 cm of tall plants receiving 3 h R. Brief R treatments resulted in smaller decreases in epidermal IAA levels and these decreases were not as great when FR followed R. In lightgrown plants, end-of-day FR stimulated growth during the following dark period in a photoreversible manner. The uppermost 1 cm of expanding third internodes was most responsive to the FR. Extractable IAA from epidermal peels from the upper 1 cm of third internodes increased by 30% or more 5 h after FR. When R followed the FR the increases were smaller. Levels of IAA in whole stem sections did not change and were twofold greater than in dark-grown plants. In both dark- and light-grown tall plants, IAA levels were lower in epidermal peels than in whole stem segments. These results provide evidence that IAA is compartmentalized at the tissue level within the growing stem and that phytochrome regulation of stem elongation rates may be partly based on modulating the level of IAA within the epidermis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01160716
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  • 2
    Electronic Resource
    Electronic Resource
    Indole-3-acetic acid levels after phytochrome-mediated changes in the stem elongation rate of dark- and light-grown Pisum seedlings (1992)
    Springer
    Planta 188 (1992), S. 85-92 
    Details
    ISSN: 1432-2048
    Keywords: Auxin and stem growth ; Epidermis and stem growth ; Pisum (stem growth) ; Phytochrome stem growth ; Stem elongation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The effect of red (R) and far-red (FR) light on stem elongation and indole-3-acetic acid (IAA) levels was examined in dwarf and tall Pisum sativum L. seedlings. Red light reduced the extension-growth rate of etiolated seedlings by 70–90% after 3 h, and this inhibition was reversible by FR. Inhibition occurred throughout the growing zone. After 3 h of R, the level of extractable IAA in whole stem sections from the growing zone of etiolated plants either increased or showed no change. By contrast, extractable IAA from epidermal peels consistently decreased 3 h after R treatments. Decreases of 40% were observed for epidermal peels from the top 1 cm of tall plants receiving 3 h R. Brief R treatments resulted in smaller decreases in epidermal IAA levels and these decreases were not as great when FR followed R. In lightgrown plants, end-of-day FR stimulated growth during the following dark period in a photoreversible manner. The uppermost 1 cm of expanding third internodes was most responsive to the FR. Extractable IAA from epidermal peels from the upper 1 cm of third internodes increased by 30% or more 5 h after FR. When R followed the FR the increases were smaller. Levels of IAA in whole stem sections did not change and were twofold greater than in dark-grown plants. In both dark- and light-grown tall plants, IAA levels were lower in epidermal peels than in whole stem segments. These results provide evidence that IAA is compartmentalized at the tissue level within the growing stem and that phytochrome regulation of stem elongation rates may be partly based on modulating the level of IAA within the epidermis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00198943
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  • 3
    Electronic Resource
    Electronic Resource
    Oriented polymer materials, Hrsg. von Stoyko Fakirov, 512 Seiten, 337 Abb, 42 Tab., Hüthig & Wepf Verlag, Zug-Heidelberg-Oxford 1996, DM 188,00, ISBN 3-85739-123-5 (1997)
    Weinheim [u.a.] : Wiley-Blackwell
    Materials and Corrosion/Werkstoffe und Korrosion 48 (1997), S. 73-74 
    Details
    ISSN: 0947-5117
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/maco.19970480117
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  • 4
    Electronic Resource
    Electronic Resource
    Polystyrol. Kunststoff Handbuch Band 4. Hrsg. von G. Becker, D. Brown, Band-Hrsg.: H. Gausepohl, R. Gellert, 767 Seiten, 628 Abb., 126 Tab., Carl Hanser Verlag, München, Wien 1995, DM 448,00, ISBN 3-446-18004-4 (1997)
    Weinheim [u.a.] : Wiley-Blackwell
    Materials and Corrosion/Werkstoffe und Korrosion 48 (1997), S. 134-134 
    Details
    ISSN: 0947-5117
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/maco.19970480210
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  • 5
    Electronic Resource
    Electronic Resource
    Material science of polymers for engineers. Von T. A. Osswald, G. Menges, 492 Seiten, 439 Bilder, Carl Hanser Verlag, München, Wien, New York 1995, DM 78.00, ISBN 3-466-17261-0 (1997)
    Weinheim [u.a.] : Wiley-Blackwell
    Materials and Corrosion/Werkstoffe und Korrosion 48 (1997), S. 198-199 
    Details
    ISSN: 0947-5117
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/maco.19970480316
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  • 6
    Electronic Resource
    Electronic Resource
    Über die Produkte der Reaktion von Methylbromid und Ethylbromid mit Kaliumhydroxid in wäßrig-methanolischen Lösungen und den Verlauf dieser SN2-ReaktionHerrn Prof. Dr. Manfred Weidenbruch zur Vollendung des 60. Lebensjahres gewidmet (1998)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 340 (1998), S. 73-80 
    Details
    ISSN: 0941-1216
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Concerning the Products of the Reaction of Methyl Bromide and Ethyl Bromide with Potassium Hydroxide in Aqueous Methanolic Solutions and the Progress of this SN2-ReactionInvestigations of the reaction of methyl bromide and ethyl bromide with potassium hydroxide in methanolic and aqueous methanolic solutions show that the main products of these reactions are dimethyl ether and ethylmethyl ether. The reaction rates measured in methanolic or aqueous methanolic solutions are the same whether potassium hydroxide or potassium methoxide are used. These results are caused by an equilibrium between hydroxide and methoxide ions with which we could establish the equilibrium constant near 0.6. This means that a solution of sodium hydroxide c = 0.1 moll-1 in methanol contains roughly 99.8% of methoxide ions. The reaction rates in methanolic as well as in aqueous methanolic solutions are strict second order. The reaction rate measured at several temperatures permitted the calculation of EA≠, ΔH≠, ΔS≠ and ΔG≠. Furthermore the kinetic investigations show that the nucleophilicity of methoxide ions is lower compared to hydroxide ions. The calculation of the Swain-Scott-parameter n results in a nucleophilicity scale in order to methoxide, hydroxide, ethoxide ions. The kinetic investigations of the reaction of ethyl bromide with methoxide and hydroxide ions in methanolic solutions demonstrate that at high temperatures the rate constant of methoxide ions is higher than that of hydroxide ions. The opposite case can be observed at lower temperatures. At the temperature of 20 °C the rate constants of both reactions are equal. This is to do with the isokinetic effect which one is rarely able to observe at room temperatures.
    Additional Material: 6 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19983400111
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  • 7
    Electronic Resource
    Electronic Resource
    Spectral holes as probes for structural transitions in polymersVortrag anläßlich der Tagung der Fachgruppe “Makromolekulare Chemie” der Gesellschaft Deutscher Chemiker über “Polymere und Licht”. in Bad Nauheim vom 7. bis 9. Mai 1990. (1990)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 183 (1990), S. 115-122 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: We show how narrow spectral holes burnt into the inhomogeneous absorption of dye doped polymers can be used as extremely sensitive detectors for measuring structural rearrangement processes. A model is suggested which relates the observed hole burning phenomena to the specific heat of the conformation phase space.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1990.051830106
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  • 8
    Electronic Resource
    Electronic Resource
    Genetische Ressourcen von Wildpflanzenarten beleben die Kulturpflanzenzüchtung (1998)
    Weinheim : Wiley-Blackwell
    Biologie in unserer Zeit 28 (1998), S. 371-380 
    Details
    ISSN: 0045-205X
    Keywords: Life and Medical Sciences
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Die Entwicklung der heute in der Landwirtschaft und im Gartenbau genutzten Kulturpflanzen ist eine der wichtigsten Leistungen in der Geschichte der Menschheit. Züchterische Maßlig;nahmen des Menschen haben zum Ziel, Pflanzen so zu verändern, daßlig; sie besser an seine Bedürfnisse angepaßlig;t sind. Die Eingriffe durch Züchtung nennt man „gelenkte Evolution“. Ausgehend von wild vorkommenden Arten hat der Mensch Nutzpflanzen geschaffen, die ohne seine Hilfe in der freien Natur auf Dauer nur geringe überlebenschancen hätten. Neben den Nutzpflanzen findet man in der Natur noch viele wilde Arten, die mit den Kulturpflanzen verwandt sind und sich häufig mit ihnen kreuzen lassen. Die wilden Arten verfügen über ein genetisches Potential, auf das in den letzten Jahren immer häufiger zurückgegriffen worden ist, um Zuchtziele des Menschen zu verwirklichen. Vor allem müssen ständig neue Resistenzen gegen Krankheiten und Schädlinge gefunden werden, um dem Infektionsdruck der Krankheitserreger zu widerstehen. Aber auch Gene für Toleranz gegenüber abiotischem Streßlig;, wie Kälte, Dürre, Salz oder Aluminiumtoxizität, sind in den Wildarten vorhanden. Sie können in die Kulturpflanzen eingekreuzt werden, um sie gegen diese Streßlig;faktoren widerstandsfähiger zu machen.Voraussetzung für den Gentransfer von einer Wildart in eine Kulturart ist ihre Kreuzbarkeit. Darüber hinaus mußlig; im Kreuzungsbastard crossing over zwischen homologen Chromosomen gewährleistet sein. Wenn die Chromosomen nicht zu natürlichem crossing over in der Lage sind, können genetische Paarungsmechanismen in der Meiose eingesetzt werden, die zu dem gewünschten Gentransfer führen.Im folgenden soll anhand von drei Beispielen die Bedeutung des genetischen Potentials wilder und verwandter Pflanzenarten für die Verbesserung der Krankheitsresistenz und Inhaltsstoffe sowie Toleranz gegen abiotischen Streßlig; bei Kulturpflanzen demonstriert werden.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/biuz.960280606
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  • 9
    Electronic Resource
    Electronic Resource
    Evolution und Züchtung des Saatweizens (Triticum aestivum L.) (1991)
    Weinheim : Wiley-Blackwell
    Biologie in unserer Zeit 21 (1991), S. 248-254 
    Details
    ISSN: 0045-205X
    Keywords: Life and Medical Sciences
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Seitdem der abendländische Mensch erkannt hatte, daß sich Getreidekörner, besonders die des Weizens, zur Mehl- und Brotherstellung eignen, ist er auf Gedeih und Verderb mit dieser Pflanzenart verbunden. Ohne den Einfluß des Menschen wären die Kulturformen von Weizen, Reis, Gerste, Hafer und Mais nicht denkbar. War er es doch, der entscheidend dazu beigetragen hat, daß sich im Laufe von Jahrtausenden unsere wichtigsten Getreidearten von ehemals spindelbrüchigen Gräsern, deren Samen nach der Reife auf den Boden fielen, Schrittweise zu zähspindeligen, nichtährenbrüchigen Hochleistungs-Nutzpflanzen umwandelten.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/biuz.19910210509
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  • 10
    Electronic Resource
    Electronic Resource
    Untersuchungen zur Plasmaätzung von Polymeren. V. Plasmaätzung von StyrenpolymerenTeil IV: Acta Polymerica 31 (1980) 310-315. (1981)
    Weinheim : Wiley-Blackwell
    Acta Polymerica 32 (1981), S. 48-55 
    Details
    ISSN: 0323-7648
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Etching rates of polystyrene and caoutchouc are similar in an oxygen plasma of a radio frequency glow discharge (nonthermal plasma). It exists a range of pressure at which the difference of rates is high enough to separate insertions of caoutchouc in polystyrene by etching of the matrix. Electron microscopic patterns of plasma, solvent, chemi-oxidative etched surfaces and break interfaces of caoutchouc and polyethylene filled probes show good agreement. The structure of chalk filled polystyrene can made visible by plasma etching technique advantageously.
    Notes: Die Ätzraten von Polystyren und Kautschuk im Sauerstoffplasma einer Hochfrequenzentladung (nichtthermisches Plasma) differieren nur wenig. In einem bestimmten Druckbereich ist der Unterschied der Ätzraten jedoch groß genug, um Kautschukeinlagerungen in Polystyren durch bevorzugtes Herausätzen der Matrix freilegen zu können. Elektronen mikroskopische Aufnahmen der plasmageätzten, lösungsmittel- und chemisch-oxidativ geätzten Oberflächen sowie von Bruchflächen ergaben bei kautschuk- und polyethylengefüllten Polystyrenproben eine gute Übereinstimmung. Die Struktur kreidegefüllter Polystyrene läßt sich vorteilhaft durch plasmachemisches Ätzen freilegen.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/actp.1981.010320111
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