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  • Cell & Developmental Biology  (2)
  • 71.25.Mg  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 61 (1995), S. 111-114 
    ISSN: 1432-0630
    Keywords: 81.15.Fg ; 68.55.Nq ; 71.25.Mg ; 82.65.My
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Amorphous carbon (a-C) films obtained by pulsed-laser ablation of graphite have been investigated by X-ray Absorption Spectroscopy (XAS). The onset of 1s →σ * transitions in the films lies in the gap between theπ * andσ * bands in graphite and very close to the absorption edge of diamond, indicating a high content ofsp 3 hybridization. A sharp feature at this onset is observed and assigned to a core exciton insp 3-hybridized disordered C atoms. Its shift of 0.5 eV with respect to the core exciton in diamond is probably due to a higher localization of the excited electron induced by disorder. A small peak coming from C−H bonds at the surface is observed and its intensity inereases with the amount ofsp 3-hybridized atoms in the sample. This can be easily explained by associating a higher amount of dangling bonds at the surface to a highersp 3 content. Polarization-dependent XAS measurements show that the angular distribution of these C−H bonds has a mean value close to the normal to the surface.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Substitution of flavianic acid (50 mM) or of a stoichiometric mixture of naphthol yellow S and hydrochloric acid, in place of picric acid in Van Gieson type mixtures gives deeper yellow colors to cytoplasm, muscle and erythrocytes. Higher concentrations of acid fuchsin can be used with consequent greater density of collagen fiber staining and improved contrast.The familiar weakening of hematoxylin nuclear stains by exposure to Van Gieson mixtures can be largely avoided by inclusion of 0.1 M ferric chloride in the Van Gieson mixture. Alum hematoxylin can then be used in place of the unstable iron hematoxylin solutions, and the iron hematoxylin effect is attained by the iron postmordanting in the Van Gieson bath. A ten minute prestain in an alum hematoxylin containing 0.5% hematoxylin is adequate but density can be enhanced by longer staining or by staining at higher temperature; 5-10 min at 60°C is suggested. The iron containing flavianic or picric acid Van Gieson staining baths should be restricted to three minutes; longer exposures gradually weaken nuclear staining.Substitution of 0.1 M copper sulfate for the iron in the Van Gieson bath also yields dark gray to black nuclei. Aluminum chloride (0.1 M) has an effect similar to the control hydrochloric acid, while the chromium ion seems quite inferior, even to the control HCl mixture.A ferrous sulfate hematoxylin ripened overnight with a small amount of ferric chloride gives excellent progressive nuclear staining, adequate in 2-5 minutes, and not excessive in 30 minutes. The solution gradually deteriorates in 6-8 weeks.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 36 (1993), S. 338-345 
    ISSN: 1040-452X
    Keywords: Sperm capacitation ; True acrosome reaction ; Oviductal epithelial cell monolayers ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The effects of different epithelial cells, namely, hamster oviduct, sheep oviduct, and pig kidney epithelial cells (IBRS-2), on the viability, percentage of progressive motility (PPM), and acrosome reactions of ejaculated ram spermatozoa were investigated. Sperm aliquots were cultured on cells, cell-conditioned medium 199, or control medium 199. The PPM of unattached spermatozoa was estimated after 0, 3, 6, 9, 12, and 24 hr of incubation at 37°C under 5% CO2 in air. Viability and the occurrence of true acrosome reactions were assessed using a triple-stain technique. Spermatozoa started to attach within 1 hr of coculture with the hamster or sheep oviductal epithelial cell (OEC) monolayers, and these spermatozoa showed vigorous tail motion. No spermatozoa were found to attach to the IBRS-2 monolayer. The PPM of unattached spermatozoa cocultured with the various types of epithelial cell monolayers for 12 hr was significantly higher than that of spermatozoa incubated in conditioned media or medium 199 alone (54% in hamster OEC vs. 40% in conditioned; 68% in sheep OEC vs. 38% in conditioned; 36% in control medium). On the other hand, after 24 hr of incubation, there were no differences in the PPM of spermatozoa cocultured with epithelial cells or incubated in conditioned media. The percentages of cells undergoing a true acrosome reaction reached maximum values (P 〈 0.05) in spermatozoa incubated for 9 hr in the presence of hamster OEC (22.5%) or for 12 hr on sheep OEC (20.5%) monolayers. IBRS-2, a commercial nonreproductive cell type, had a positive influence on both PPM and sperm viability but no effect on the occurrence of the acrosome reaction. Interactions leading to the acrosome reaction were thus observed only when spermatozoa were cocultured with OEC monolayers. The values of PPM in unattached sperm cells seen after 12 hr of coculture with OEC or IBRS-2 were still at a high level (52-67%) for in vitro fertilization. The coculture with OECs provides an “in vitro” model to study the capacitation processes in a situation that may resemble that occurring in vivo. Moreover, the coculture with hamster OECs may provide a convenient and standardized in vitro system to study mechanisms underlying capacitation and the acrosome reaction. © 1993 Wiley-Liss, Inc.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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