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  • Articles  (75)
  • Polymer and Materials Science  (72)
  • Aleurone  (2)
  • 33BAPB
  • 42.60D
  • CYBERNETICS
  • 1990-1994  (20)
  • 1985-1989  (24)
  • 1980-1984  (31)
  • 1
    Electronic Resource
    Electronic Resource
    Four-branch oscillation from a dual-polarization cavity CO2 laser (1993)
    Springer
    Applied physics 57 (1993), S. 227-230 
    Details
    ISSN: 1432-0649
    Keywords: 42.55E ; 42.60D
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We report here for the first time multiline oscillation of a cw-CO2 laser on all the four branches 10P, 10R, 9P, and 9R where all laser wavelengths share a common gain medium. The 9R, 9P and 10R branch lines lased at the expense of the high-gain 10P branch lines for which the cavity offered very high transmission losses. The 10P(20) line was made to lase by constructing another cavity with orthogonal polarization, thereby easing the strong competition between this line and the relatively low-gain 9R, 9P and 10R branch lines within the gain medium which is common to both cavities.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00334539
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  • 2
    Electronic Resource
    Electronic Resource
    Hormonal regulation of Ca2+ transport in the endomembrane system of the barley aleurone (1993)
    Springer
    Planta 189 (1993), S. 507-515 
    Details
    ISSN: 1432-2048
    Keywords: Abscisic acid ; Aleurone ; Calcium transport ; Endomembrane system ; Gibberellin ; Hordeum (Ca2+transport)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Gibberellic acid (GA3) and abscisic acid (ABA) regulate α-amylase production in aleurone tissue of the barley (Hordeum vulgare L.) grain during germination. Since α-amylase is a Ca2+-containing protein that is synthesized on the rough endoplasmic reticulum (ER), we investigated the possibility that GA3 and ABA regulate the flux of Ca2+ into the ER of aleurone cells. Membrane vesicles were isolated from GA3- and ABA-treated aleurone layers to characterize the effect of these hormones on calcium transport (CaT) activity as measured by the uptake of 45CaCl2 in vitro. We found that ABA and GA3 greatly alter the relative amounts of CaT activity in ER and tonoplast (TP) membrane fractions. Treatment with GA3 results in CaT being associated primarily with the ER, whereas treatment with ABA results in roughly equal amounts of CaT in ER and TP. Moreover, we found that ABA prevents or reverses the GA3-induced increase in CaT in the ER. The effects of ABA and GA3 on CaT in the ER require several hours to develop, and the effects of these hormones on CaT cannot be brought about by adding the hormones to membranes in vitro. In order to determine whether the in-vitro measurements of CaT reflect changes that occur in vivo we measured the Ca2+ content of isolated ER, measured Ca2+ transport into aleurone layers, and examined differences in the ability of ER proteins from GA- and ABA-treated layers to bind Ca2+. Our results indicate that GA3 increases and ABA decreases both Ca2+ flux into the ER and the amount of calcium that accumulates in the ER of barley aleurone cells in vivo.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00198213
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  • 3
    Electronic Resource
    Electronic Resource
    Gibberellic-acid-stimulated Ca2+ accumulation in endoplasmic reticulum of barley aleurone: Ca2+ transport and steady-state levels (1989)
    Springer
    Planta 178 (1989), S. 411-420 
    Details
    ISSN: 1432-2048
    Keywords: Aleurone ; Calcium transport ; Endoplasmic reticulum (Ca2+ levels) ; Gibberellin and Ca2+ transport ; Golgi apparatus ; Hordeum (Ca2+ transport) ; Microsome
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The steady-state levels of Ca2+ within the endoplasmic reticulum (ER) and the transport of 45Ca2+ into isolated ER of barley (Hordeum vulgare L. cv. Himalaya) aleurone layers were studied. The Ca2+-sensitive dye indo-1. Endoplasmic reticulum was isolated and purified from indo-1-loaded protoplasts, and the Ca2+ level in the ER was measured using the Ca2+-sensitive dye indo-1. Endoplasmic reticulum was isolated and purified from indo-1-loaded protoplasts, and the Ca2+ level in the lumen of the ER was determined by the fluorescence-ratio method to be at least 3 μM. Transport of 45Ca2+ into the ER was studied in microsomal fractions isolated from aleurone layers incubated in the presence and absence of gibberellic acid (GA3) and Ca2+. Isopycinic sucrose density gradient centrifugation of microsomal fractions isolated from aleurone layers or protoplasts separates ER from tonoplast and plasma membranes but not from the Golgi apparatus. Transport of 45Ca2+ occurs primarily in the microsomal fraction enriched in ER and Golgi. Using monensin and heat-shock treatments to discriminate between uptake into the ER and Golgi, we established that 45Ca2+ transport was into the ER. The sensitivity of 45Ca2+ transport to inhibitors and the Km of 45Ca2+ uptake for ATP and Ca2+ transport in the microsomal fraction of barley aleurone cells. The rate of 45Ca2+ transport is stimulated several-fold by treatment with GA3. This effect of GA3 is mediated principally by an effect on the activity of the Ca2+ transporter rather than on the amount of ER.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00391870
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  • 4
    Electronic Resource
    Electronic Resource
    Conformational analysis of the milk oligosaccharides (1980)
    New York : Wiley-Blackwell
    Biopolymers 19 (1980), S. 1555-1566 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Possible conformations of lacto-N-tetraose, lacto-N-neotetraose, related disaccharides, and other milk oligosaccharides have been studied by an energy-minimization procedure using empirical potential functions. Lacto-N-tetraose favors a “curved” conformation, while lacto-N-neotetraose favors an approximately “straight” conformation. These two conformations differ mainly in the position of the terminal galactose residue with respect to the rest of the molecule. This difference explains the greater strength of lacto-N-neotetraose compared with lacto-N-tetraose in its ability to inhibit the cross-reaction of blood group P1 fractions with Type XIV pneumococcal antipolysaccharide. Although the favored conformation of lacto-N-tetraose (inactive) agrees with the model proposed by the earlier workers, that for lacto-N-neotetraose (active) differs. The favored conformations for the disaccharides galactose-β(1-4)-N-acetylglucosamine, galactose-β(1-3)-N-acetylglucosamine, and lactose are similar in overall shape, differing only in the nature and orientation of the side groups. This explains their nearly equal inhibitory activity. These theoretical models also explain the increased activity of lacto-N-fucopentaose I over that of lacto-N-tetraose and the relative activities of the substituted lactoses. The present studies suggest that it is the overall shape of the molecule which is important for activity, rather than the terminal β(1-4)-linked galactose residue alone.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1980.360190811
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  • 5
    Electronic Resource
    Electronic Resource
    Synthesis and some properties of carbazole modified polyvinylchloride and the cation exchange resin therefrom (1989)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 170 (1989), S. 115-125 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Durch Substitution von Chlor in PVC durch 3,6-Diamino-N-methyl-carbazol entsteht ein Kondensat, das in allen Lösungsmitteln für PVC unlöslich ist. Dieses Kondensat ist thermisch stabiler als PVC. Auch die dielektrischen Eigenschaften unterscheiden sich deutlich von denen von PVC. Die Sulfonierung des PVC-Carbazol-Kondensats liefert ein Kationenaustauscherharz mit SO3H- und COOH-Gruppen.
    Notes: The chlorine displacement reaction between PVC and N-methylcarbazole-3,6-diamine affords a condensate which is insoluble in all possible solvents of PVC. The overall thermal stability of this condensate is appreciably higher than that of PVC. The dielectric behavior is also significantly different from that of unmodified PVC. Sulfonation of the PVC-carbazole condensate affords a cation-exchange resin with —SO3H and —COOH functional moieties.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1989.051700108
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  • 6
    Electronic Resource
    Electronic Resource
    Phenomenological model for the unified studies of different physical properties of polymers (1993)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 207 (1993), S. 9-21 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Es wird ein phänomenologisches Modell vorgestellt, mit dem sich das Entstehen starker Anisotropien der physikalischen Eigenschaften semikristalliner Polymerer nach einachsigem Verstrecken beschreiben 1äßt. Dieses Modell führt die Temperatur als expliziten Parameter in die Orientierungsfunktion ein. Es enthält zwei frei wählbare Parameter, die für jedes Polymere durch Anpassen der experimentellen Daten der Doppelbrechung als Funktion des Verstreckverhältnisses bei einer bestimmten Temperatur ermittelt werden konnen. Die berechneten Werte für Elastizitätsmodul, thermische Leitfähigkeit und Expansibilität parallel und senkrecht zur Streckrichtung stimmen in einem wäiten Bereich des Verstreckverhältnisses und der Temperatur mit den experimentellen Ergebnissen gut überein.
    Notes: A phenomenological model has been proposed to understand the development of strong anisotropy in physical properties of semicrystalline polymers on uniaxial drawing. The proposed model introduces temperature as an explicit parameter in the orientation function. The model contains two free parameters for each polymer which can be evaluated by fitting the experimental data on birefringence versus draw ratio at a particular temperature. The calculated values of elastic moduli, thermal conductivity and expansibility along and perpendicular to the drawing direction over the entire range of draw ratio and a wide range of temperature are in good agreement with experimental values.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1993.052070102
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  • 7
    Electronic Resource
    Electronic Resource
    Unified study of the mechanical and optical properties of polyoxymethylene applying the composite model for the temperature range from -60 to 120°C (1986)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 187 (1986), S. 1017-1022 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A unified study of the optical and mechanical properties of polyoxymethylene (POM) is attempted in the framework of the composite model for a wide range of temperature (-60 to 120°C) which covers a region well below and above the γ-relaxation temperature. It was found that the existing two phase models for semicrystalline polymers are not adequate for interpreting the mechanical properties of POM over a wide temperature and drawing ratio range. The composite model takes into consideration the effects due to the change in crystallinity and orientation on drawing. The elastic moduli of the composite units are also calculated in terms of those of its constituents. The orientational changes on drawing were directly computed from the birefringence data. It was observed that the general agreement of the calculated and experimental values of the elastic moduli over the entire temperature and drawing ratio range is quite satisfactory.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1986.021870430
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  • 8
    Electronic Resource
    Electronic Resource
    Composite model calculation of the mechanical properties of polypropylene (1986)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 187 (1986), S. 1023-1034 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The theoretical interpretation of the anisotropic elastic properties of polypropylene is given. It was found that none of the existing models provide a unified description of the mechanical and optical properties of ultradrawn polypropylene. The composite model proposed by the authors, which takes into account the change in orientation and crystallinity on drawing, was applied to investigate the elastic moduli data of polypropylene for a wide range of temperature (-40 to 110°C) and over the entire drawing ratio range. The relationship between θ and θ′, the angles made by the C-axis of the composite unit with drawing direction, was found to be adequately described by the relation tan θ = φ(n) tan θ′. It was further observed that φ(n) in the above relation obtained from birefringence data predicts the correct orientational changes on drawing for the temperature range -40 to 24°C. This makes the evaluation of mechanical properties possible without introducing any arbitrary parameter. However, it is noticed that a particular analytical form of φ(n) with two parameters is quite successful in interpreting the mechanical properties data over the entire temperature range. The abrupt changes of the parameters at certain temperatures seem to be correlated with the β-relaxation and glass transition temperature.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1986.021870431
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  • 9
    Electronic Resource
    Electronic Resource
    A composite model for the thermal conductivity of semicrystalline polymers (1987)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 188 (1987), S. 217-226 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A phenomenological model is proposed which considers the polymer as an aggregate of units. The units are composed of two distinct phases  -  amorphous and crystalline. The thermal conductivity of a unit is calculated in terms of those of its constituents. In the undrawn state these units are distributed randomly, and the isotropic thermal conductivity of the bulk results. The development of strong anisotropy in thermal conductivity is explained in terms of the preferred orientation of these units. The structural features of this model are similar to those employed for the interpretation of the mechanical properties. The change in orientation of the units was deduced from the experimental data of birefringence. Finally, the results obtained from the composite model for several semicrystalline polymers are compared with the experimental data and other existing calculations. The model is found to give a fair overall description of the thermal conductivity in the cases of polypropylene, polyoxymethylene, low and high density polyethylene, and polychlorotrifluoroethylene.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1987.021880118
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  • 10
    Electronic Resource
    Electronic Resource
    Aqueous polymerization of methyl methacrylate using quinoline-sulfur dioxide complex and tetrahydrofuran-sulfur dioxide complex as initiators (1980)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 181 (1980), S. 1331-1338 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Aqueous polymerization of MMA was kinetically studied using separately two complexes of sulfur dioxide as initiators, namely, quinoline-sulfur dioxide (Q-SO2) complex and tetrahydrofuran-sulfur dioxide (THF-SO2) complex. In each case the initiator exponent was 0,5 and the monomer exponent was 1,5. Kinetic data, inhibitory effect of hydroquinone, and incorporation of sulfoxy end groups in the polymers indicate a radical mechanism of polymerization with first order dependence on monomer for the rate of initiation while termination appears to take place bimolecularly.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1980.021810613
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