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  • 1985-1989  (9)
  • Engineering General  (5)
  • Chemistry  (3)
  • Temperature (chilling)  (1)
  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Planta 164 (1985), S. 512-516 
    ISSN: 1432-2048
    Schlagwort(e): Chilling injury ; Solanum ; Temperature (chilling) ; Undercooling
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Electrolyte leakage was measured in “hardened” and “nonhardened” leaves of three potato species, Solanum tuberosum L., S. acaule Bitt. and S. commersonii Dun., and one interspecific cross, “Alaska Frostless” (S. acaule x S. tuberosum) when exposed to various subzero temperatures. The leaves were undercooled (no ice present) from 0°C to -12.5°C for 45 min and to-4°C for up to 10 d. Regardless of the degree of undercooling no injury was observed in any of the potatoes, “hardened” or “nonhardened”, for up to 12 h. After 5 d, however, electrolyte leakage was observed in “hardened” S. tuberosum, S. acaule and S. commersonii, and in “nonhardened” “Alaska Frostless”. After 10 d exposure all potatoes, “hardened” and “nonhardened”, showed a significant amount of electrolyte leakage as compared to their controls kept at 0°C for 10 d.
    Materialart: Digitale Medien
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  • 2
    ISSN: 0887-3585
    Schlagwort(e): bioactivity ; SK-hep-1 hepatoma ; interleukin-1 ; recombinant protein ; crystals ; Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: The gene for human interleukin-1β was cloned from SK-hep-1 hepatoma cellular RNA and expressed at high levels in Escherichia coli both as the naturally processed form (rIL-1β) and as a variant with an additional sequence of three amino acids on the N-terminus (rIL-1β+). Expressed protein was purified to homogeneity by a sequence of steps, which included low pH incubation, adsorption and desorption from Procion Red Sepharose, sizing on a Superose 12 fast-performance liquid chromatography (FPLC) column, and anion exchange chromatography on QAE Sepharose. The final step provided a biologically active protein that migrates on twodimensional (2-D) gels as a single spot with a pI of 6.7 ± 0.2 and a molecular mass of 17,500 daltons. Concentrated solutions of rIL-1β have produced crystals by ammonium sulfate precipitation. The crystals are tetragonal, show the symmetry of space group P41 or its enantiomer, have lattice constants of a = 58.46 (1) and c = 77.02 (3) A, and scatter to at least 2 Å resolution. A structure determination based on these crystals is under way.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 22 (1988), S. 137-148 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: Studies have shown synthetic calcium phosphates such as hydroxyapatite and beta tricalcium phosphate to be biocompatible in vivo. However, few studies have quantitated histological responses to the implants.The aim of this study was to develop a method for the quantitative assessment of tissue biocompatibility to ceramic materials in vivo and to use this method to compare noncarbonated and carbonated apatite implants. Synthetic sintered apatites of 0, 3, and 6% carbonate by weight were prepared and cut into implants 4 × 4 × 1 mm. These were placed 2 mm into the medial aspect of rat fermurs. Following sacrifice at 4 weeks, the femurs were fixed in formalin, demineralized in formic acid, and embedded in glycol methacrylate. Sections were cut on an ultramicrotome set at 1.5 μm and stained with toluidine blue. A point counting technique using standard stereological grids and a low-power microscope was used to measure areas of new bone formation. The width of the connective tissue zone adjacent to muscle was measured using an image analyzer. All implants were well accepted by the host tissues judging from criteria of minimal inflammation and degree of fixation. Results showed an increase in new bone formed in the marrow cavity with increasing carbonate content. This may improve stability of the implant in the host bone, particularly during the initial healing period. A technique which should enable quantitative histological evaluation of different ceramic materials has been developed. The use of this method indicates that further studies are warranted to investigate carbonated apatite as an implant material.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 4
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: In order to study the influence of residual stresses on dimensional accuracy and mechanical properties of denture bases, an experimental model was devised for measurement of residual stresses in acrylic denture base polymers. Rectangular bar coupons were cut from resin plates heat processed by conventional dental methods. They included samples which had been slow and fast cooled after polymerization and had been stored in dry and wet environments. Uniaxial residual stress distributions for each coupon were disclosed by removing layers of known thicknesses and measuring the ensuing deflection of the specimens. Coupons of a commercial acrylic resin were annealed and used as controls. ANOVA and Scheffe's test were used to compare experimental conditions at the 95% confidence level. Dry specimens exhibited residual surface compressive stresses from 0.43-0.83 MPa (62-120 psi). Water-stored specimens showed higher stress levels, 2.86-3.24 MPa (414-470 psi). Slow cooled pigmented acrylic coupons which were dry showed higher residual stresses compared with other dry but nonpigmented specimens. No significant differences were found between pigmented or clear coupons which contained moisture.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
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  • 5
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    International Journal for Numerical and Analytical Methods in Geomechanics 11 (1987), S. 61-77 
    ISSN: 0363-9061
    Schlagwort(e): Engineering ; Engineering General
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Architektur, Bauingenieurwesen, Vermessung , Geologie und Paläontologie
    Notizen: The complete solution is presented for the transient effects of pumping fluid from a point sink embedded in a saturated, porous elastic half-space. It is assumed that the medium is homogeneous and isotropic with respect to its elastic properties and homogeneous but anisotropic with respect to the flow of pore fluid. The soil skeleton is modelled as a linear elastic material obeying Hooke's law, while the pore fluid is assumed to be incompressible with its flow governed by Darcy's law. The solution has been evaluated for a particular value of Poisson's ratio of the solid skeleton, i.e. 0.25, and the results have been presented graphically in the form of isochrones of excess pore pressure and surface profile for the half-space. The solutions presented may have application in practical problems such as dewatering operations in compressible soil and rock masses.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 6
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    International Journal for Numerical and Analytical Methods in Geomechanics 10 (1986), S. 137-150 
    ISSN: 0363-9061
    Schlagwort(e): Engineering ; Engineering General
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Architektur, Bauingenieurwesen, Vermessung , Geologie und Paläontologie
    Notizen: Closed-form solutions are presented for the steady-state distributions of displacement, pore pressure and stress around a point sink embedded in a homogeneous, isotropic elastic half space. These solutions have been evaluated for a typical case of a sink (pump) buried in sand and the magnitude of the settlement of the ground surface has been estimated.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
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  • 7
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    International Journal for Numerical and Analytical Methods in Geomechanics 13 (1989), S. 19-36 
    ISSN: 0363-9061
    Schlagwort(e): Engineering ; Engineering General
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Architektur, Bauingenieurwesen, Vermessung , Geologie und Paläontologie
    Notizen: A spherical cavity expansion model has been used to study the bearing capacity of foundations on calcareous and silica sands. Two constitutive models have been used to represent each sand: an elastoplastic, collapse-softening model, and a computationally simpler, elastic/perfectly plastic material. The predictions of the limit pressures for spherical cavity expansion are compared with laboratory data on the bearing capacities obtained from model footing tests. It is shown that the numerical predictions of the limit pressures correlate well with the experimental values of bearing capacity, particularly at higher effective overburden pressures.
    Zusätzliches Material: 10 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 8
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    International Journal for Numerical and Analytical Methods in Geomechanics 13 (1989), S. 101-107 
    ISSN: 0363-9061
    Schlagwort(e): Engineering ; Engineering General
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Architektur, Bauingenieurwesen, Vermessung , Geologie und Paläontologie
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 9
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    International Journal for Numerical and Analytical Methods in Geomechanics 12 (1988), S. 197-212 
    ISSN: 0363-9061
    Schlagwort(e): Engineering ; Engineering General
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Architektur, Bauingenieurwesen, Vermessung , Geologie und Paläontologie
    Notizen: Previous field and laboratory studies have shown that the creation of a borehole in a saturated cohesive soil mass induces significant pore water suctions in the vicinity of the hole. The dissipation of these pore water suctions (swelling) leads to local increases in the moisture content and hence a softening of the soil around the hole. This softening may have important consequences for the stability of the hole and also for the ultimate load capacity of any foundation elements (bored piles or drilled shafts) constructed in these holes. This paper presents a semi-analytical solution for the radial dissipation of pore water pressure around a freshly created, vertical hole. It is assumed the soil deforms elastically during the swelling process. The solutions are presented in the form of isochrones of excess pore water pressure and may be used to obtain estimates of the time required for the soil around the hole to swell and therefore to soften. Both permeable and impermeable borehole interfaces have been considered, together with either no support for the hole or partial support provided by hydrostatic pressure within the hole.
    Zusätzliches Material: 10 Ill.
    Materialart: Digitale Medien
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