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  • 2000-2004
  • 1980-1984  (6)
  • 1940-1944
  • Chemistry  (4)
  • spermatozoa  (2)
  • 1
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Gamete Research 8 (1983), S. 255-265 
    ISSN: 0148-7280
    Schlagwort(e): antigens ; plasma membrane ; intracellular ; monoclonal antibodies ; spermatozoa ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: Fluorescent antibody labeling techniques are frequently used to investigate the topography of antigens on spermatozoa. It is generally assumed that these procedures detect molecules only on the sperm surface but we now show that this assumption is not always valid. Using monoclonal antibodies that recognize either surface or internal antigens we demonstrate how spurious conclusions can be made, and we suggest simple procedures for assigning the position of an antigen to the cell surface or to an intracellular organelle. Antibodies against plasma membrane antigens should stain 100% of normal intact spermatozoa, but this proportion should be greatly reduced if the spermatozoa have previously been demembranated. If ≪ 100% of spermatozoa are stained but the proportion increases following permeabilization, then the possibility should be considered that the antigens are intracellular. We conclude that assignment of an antigen to a regional domain on the sperm surface using fluorescent antibody techniques should be validated by a demonstration that the antigen is actually located on the cell surface.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Gamete Research 9 (1984), S. 131-144 
    ISSN: 0148-7280
    Schlagwort(e): spermatozoa ; human ; motility ; activated motility ; hyperactivated motility ; capacitation ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: Ten frames/sec microcinematography (“film”), 1 second timed-exposure photomicrography (“photo”), and laser Doppler velocimetry (LDV) were used to analyse the swimming patterns of human spermatozoa after migration (1 h at 37°C) into an overlying layer of either BWW or Menezo's B2 media. The upper layer of medium was carefully removed and further incubated at 37°C for either 4 h (B2) or 5 h (BWW) and the sperm motility analysed again. Five experiments were performed using semen from different donors. Film and photo analyses gave the relative incidence of nonprogressive and progressively motile spermatozoa plus, for the progressive spermatozoa, the velocities of progression (Vp) and amplitudes of lateral head displacement (Ah). LDV gave the percentage of motile spermatozoa and the modal instantaneous velocity (Vm). All postmigration sperm populations showed large significant increases in the percentage of motile spermatozoa, with good survival during incubation. The progressive postmigration spermatozoa generally moved with greater Vp and Ah than in the initial seminal plasma-diluted material; Vm was also increased. There were further increases in both Vp and Ah during incubation, but no change in Vm was detected. While the majority of spermatozoa were progressive, some showed a highly active pattern of movement which resulted in no net forward progression. The possible homology between these spermatozoa and the “hyperactivated” motility of capacitated spermatozoa in other mammalian species is discussed. Apparent discrepancies between the three methods used for motility analysis were seen, the possible causes and significances of which are also discussed.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 11 (1984), S. 332-339 
    ISSN: 0306-042X
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Numerous abnormal metabolites were identified in large amounts in the urine of hypoglycin-treated rats using capillary gas chromatography/mass spectrometry-computer analysis. These metabolites are not detectable in significant amounts in normal rats' urine. Ten of them have not been previously associated with hypoglycin administration: these are several hydroxy compounds, including those from the valine and isoleucine pathways, 2-oxo-adipic acid, n-butyrylglycine and isovaleryl glucuronide. These results indicate that the pathways of isoleucine and valine netabolism are inhibited at their respective acyl-CoA dehydrogenation steps, as is the case for fatty acid, leucine and lysine metabolism, as previously shown. The mass spectra of the trimethylsilyl derivatives of cis, cis-4,7-decadiene-1,10-dioic, cis-4-decene-1,10-dioic, cis-4-octene-1,8-dioic acids, and (methylenecyclopropyl)acetylglycine, which were previously identified using nuclear magnetic resonance and oxidative cleavage or acid hydrolysis, are presented for the first time.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 4
    ISSN: 0278-4513
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 5
    Digitale Medien
    Digitale Medien
    Brookfield, Conn. : Wiley-Blackwell
    Polymer Composites 1 (1980), S. 56-61 
    ISSN: 0272-8397
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Maschinenbau
    Notizen: Standard test methods ASTM D-651 for determining tensile properties and ASTM D-790 for flexure properties are evaluated. Heterogeneous fiber distributions due to molding flow conditions are shown to yield test specimens wherein fiber orientation near surfaces is highly collimated while orientations in central regions are oriented approximately transverse to the specimen axis. In addition, the converging and diverging flow fields in the dog bone (ASTM D-651) specimen with end gate are shown to yield a variation in fiber orientation along the specimen length. Finite element analysis of the dog bone (ASTM D-651) reveals that stress concentrations and a non-uniform stress distribution are introduced due to the required gripping arrangement of the test standard. The flexural specimen is decomposed into two elements of a collimated and transverse fiber orientations and a mathematical model is developed which reflects the composite behavior of the beam specimen. Finally, it is concluded that the D-651 and D-790 test methods do not reveal intrinsic design data for fiber reinforced molding materials.
    Zusätzliches Material: 10 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 6
    Digitale Medien
    Digitale Medien
    Brookfield, Conn. : Wiley-Blackwell
    Polymer Composites 3 (1982), S. 34-39 
    ISSN: 0272-8397
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Maschinenbau
    Notizen: The behavior of polymeric materials reinforced by discontinuous. Descriptors for the planar and axial orientation distributions are discussed. Predictions of micromechanical models and experimental data are presented to illustrate the influence of orientation state upon elastic constants, thermal coefficients of expansion and tensile strength. Results are presented for the notched strength and compressive creep behavior of the glass/phenolic composite of two orientation states. Finally, the implications of these results upon the design of elements molded of discontinuous fiber composites are discussed.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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