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  • 1980-1984  (6)
  • Engineering General  (2)
  • Polymer and Materials Science  (2)
  • Rhizobium  (2)
  • 1
    Electronic Resource
    Electronic Resource
    Enhanced nodulation of leguminous plant roots by mixed cultures ofAzotobacter vinelandii and rhizobium (1981)
    Springer
    Plant and soil 62 (1981), S. 399-412 
    Details
    ISSN: 1573-5036
    Keywords: Azotobacter ; Glycine max ; Nodulation ; Rhizobium ; Trifolium repens ; Vigna unguiculata
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Azotobacter vinelandii strains caused the formation of increased numbers of root nodules onGlycine max, Vigna unguiculata andTrifolium repens by their respective rhizobial symbionts. Increased nodulation due to inoculation withA. vinelandii also occurred in field grownG. max. Mutant strains ofA. vinelandii unable to fix nitrogen caused nodulation increases comparable to those caused by nitrogen-fixing strains. This indicates that nitrogen fixation byA. vinelandii was not responsible for the enhanced nodulation. The effect ofA. vinelandii on nodulation was greatest when cells from the mid-exponential phase of growth were applied as inoculants. Non viable cell preparations ofAzotobacter vinelandii were also found to cause an increase in the number of root nodules formed onGlycine max Rhizobium japonicum under greenhouse conditions. The nodulation enhancement activity was influenced by the method chosen to kill theA. vinelandii cells. Heat treatment and treatment with lethal levels of streptomycin destroyed the activity, whereas the activity was unaffected by ultraviolet-light treatment of the cells. Cell-free extracts ofA. vinelandii were found to enhance nodulation. On the other hand, culture supernatants ofA. vinelandii had no effect on nodulation. A split-root experiment suggested that the agent(s) responsible for the increased nodulation was not translocatable throughout the plant. The results suggest a non-excretable protein, produced byA. vinelandii, as a possible mechanism for nodulation enhancement.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02374137
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Isolation and partial characterization of Fix− mutants from Rhizobium strain 32H1 (1983)
    Springer
    Plant and soil 74 (1983), S. 395-406 
    Details
    ISSN: 1573-5036
    Keywords: Fix− mutants ; Fix+ revertants ; Macroptilium lathyroides ; Nitrogen fixation ; Rhizobium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Eight ineffective mutant strains were isolated from N-methyl-N'-nitro-N-nitrosoguanidine mutagenized cultures of cowpea Rhizobium strain 32H1. Strains CR1, CR2, CR3, CR4, CR5 and CR6 induced more, but smaller, nodules than the wild type. With the exception of strain CR2, these mutant strains reduced less than 1% of the amount of acetylene reduced by the wild type, in both the free-living and symbiotic assays. Strain CR2 reduced acetylene in the free-living assay but not in the symbiotic assay. Strains CR7 and CR8 responded variably (5–20% of the wild type) in free-living and symbiotic acetylene reduction assays. Nodules also varied from small white to normal-sized pink nodules. The phenotypic characteristics of the mutant strains were consistant with all leguminous plants tested and were stable upon reisolation from nodules. Fully effective revertants were selected from 4 of the ineffective mutant strains by the use of the leguminous plant,Macroptilium lathyroides. Serology, patterns of resistance to anti-bacterial agents, phage-typing, and antibiotic resistance markers were used to confirm strain identification.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02181357
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Second-order design sensitivity analysis of mechanical system dynamics (1982)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 18 (1982), S. 1699-1717 
    Details
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: Dependence of dynamic response of nonlinear mechanical systems on design variables is analysed. An adjoint variable method is used to derive first- and second-order derivatives of measures of dynamic response with respect to design variables. A computational algorithm is presented for numerical calculation of first and second design derivatives. A simple oscillator example is solved analytically and by the adjoint variable method, with identical results. A burst fire automatic weapon mechanism with linear and nonlinear damping is treated numerically. It is shown that quadratic appriximations of dynamic response, using results of second-order design sensitivity analysis, can be substantially better than conventional linear approximations.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/nme.1620181109
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  • 4
    Electronic Resource
    Electronic Resource
    Kinetics of macromolecules reacting with ligand (1980)
    New York : Wiley-Blackwell
    Biopolymers 19 (1980), S. 857-883 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In order to get an idea of the transient and stationary behavior to be looked for in a biological macromolecular system such as an enzyme or respiratory protein in the presence of its ligands, we have studied the coupled kinetic equations applicable to a simple allosteric model, based on the concerted two-state model of Monod et al. [(1965) J. Mol. Biol. 12, 88-118]. Exact solutions of the equations are given for three special cases, and two complementary methods are developed to generate approximate solutions in the general case, always, however, with the assumption that the equations are linear due to maintenance of ligand activity at a constant level. Subject to this assumption, these approximation methods have applicability to coupled rate equations beyond those considered here. As an illustration of how the results can provide the basis for a detailed analysis of actual kinetic data on working proteins, the formalism is applied to the kinetics of binding of oxygen by hemoglobin. An important result is that although time evolution to the steady state is in principle determined by several relaxation times, the effect of cooperativity for the case considered is to establish the dominance of one of them relative to the others. This suggests that for a macromolecule with a large number of binding sites, only one, or at most a few, of the many possible relaxation times are significant for specification of cooperative kinetics. The methods developed here, which will be applied more extensively elsewhere, provide a systematics for finding these dominant relaxation times.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1980.360190411
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  • 5
    Electronic Resource
    Electronic Resource
    A two-parameter model for estimating hydrogen bond enthalpies of reaction (1980)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 25 (1980), S. 2975-2984 
    Details
    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: A two-parameter equation is developed that allows for the estimation of the enthalpies of hydrogen formation between two compounds. The compound acting as a proton donor is assigned a donating parameter, and the compound acting as a proton acceptor is assigned an accepting parameter. The compounds described can be assigned both a donating and an accepting parameter. These parameters are derived either from the observed linear relationship between measured hydrogen bond enthalpies and the shift in the OH stretching frequency of alcohols or from the estimated contribution of hydrogen bonding to the cohesive energy density of liquids. The donating parameters correlate well with observed autoprotolysis constants for the several compounds, and the accepting parameters correlate well with observed equilibrium constants for the protonation reaction in which a compound (base) gains a proton. The ability to estimate enthalpies is important in predicting polymeric resin solubilities in solvents.
    Additional Material: 9 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1980.070251228
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  • 6
    Electronic Resource
    Electronic Resource
    Non-associative constitutive laws for low porosity rocks (1983)
    New York, NY [u.a.] : Wiley-Blackwell
    International Journal for Numerical and Analytical Methods in Geomechanics 7 (1983), S. 101-115 
    Details
    ISSN: 0363-9061
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Architecture, Civil Engineering, Surveying , Geosciences
    Notes: Two simple constitutive laws appropriate for elastic-plastic deformation up to peak load of low porosity rocks are presented. Both laws account for mean stress dependence of yield hardening between yield and peak strength and non-associative plastic straining. The two constitutive laws are based on the Mohr-Coulomb and the Mises-Schleicher yield criteria. The yield criteria are matched at axisymmetric compression and the relationships among the constitutive parameters are given. The parameters are then evaluated for two evaporite rocks anhydrite and polyhalite based on axisymmetric compression data. Comparison of predicted stress-strain laws with those measured in the laboratory show that these laws can be used for engineering analysis.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/nag.1610070110
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