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  • 2005-2009  (1)
  • 1995-1999  (4)
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  • 1
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 81 (1997), S. 6141-6146 
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Silicon carbide films were grown on (100) silicon substrates by deposition of 200-nm-thick C60 films, followed by annealing. The predeposited C60 is progressively destroyed by annealing, and carbon reacts with silicon to produce SiC. The reaction starts at the interface and continues by diffusion of silicon through the already formed SiC. At the lower temperatures (700 °C), the reaction is localized at the interface. Diffusion of silicon and formation of stoichiometric SiC requires annealing at 800 °C for t≥100 min and at 900 °C for t≥25 min. The stoichiometric films are uniform with a grain size of 20–40 nm. A diffusion coefficient of silicon in SiC of 4×10−15 cm2/s at 900 °C was determined. Because the diffusion of silicon is faster through preferential paths in the SiC film, such as grain boundaries and other crystalline defects, pits and voids are produced in the silicon substrate when the C60 predeposited film covers larger areas. © 1997 American Institute of Physics.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Oxford, UK; Malden, USA : Blackwell Science Ltd
    Journal of fish biology 67 (2005), S. 0 
    ISSN: 1095-8649
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Biologie
    Notizen: Involution and resorption of both postovulatory and atretic follicles were analysed in piau-jejo Leporinus taeniatus(Characiformes, Anostomidae) in order to evaluate the role of apoptosis during ovarian regression. Histological and ultrastructural analyses showed hallmarks of apoptosis in the granulosa: aggregation of compacted chromatin against the nuclear envelope, cell shrinkage, surface blebbing, loss of cell adhesion and cell fragmentation into apoptotic bodies. Protein synthesis activity preceded the onset of the cell death. The breakdown of the basement membrane led to the detachment of the granulosa cells into the follicular lumen. TUNEL-positive reactions were detected in in situ DNA fragmentation of granulosa of both postovulatory and atretic follicles. Apoptosis increased in a time-dependent manner contributing to reduction of the follicular areas. The apoptotic index (per cent of apoptotic cells) of the granulosa increased in postovulatory follicles soon after spawning, then these follicles degenerated and only remnants were observed at 7 days. In contrast, the granulosa cells reabsorbed the yolk during follicular atresia and the apoptotic index increased only in the late stage of regression. The results indicated apoptosis as the major mechanism to rapidly eliminate postovulatory follicles and being an essential process in the ovarian regression after spawning.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    s.l. : American Chemical Society
    The @journal of physical chemistry 〈Washington, DC〉 99 (1995), S. 17785-17788 
    Quelle: ACS Legacy Archives
    Thema: Chemie und Pharmazie , Physik
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    Springer
    Calcified tissue international 57 (1995), S. 415-418 
    ISSN: 1432-0827
    Schlagwort(e): Pyridinium cross-links ; Bile ; Excretion
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Abstract This study evaluated whether pyridinium cross-links, which are positively charged, besides renal clearance are also cleared by the liver into bile. In 13 human bile samples tested, we were able to detect both pyridinoline (PYD) and deoxypyridinoline (DPD) in small amounts which were estimated to be about 1–2% of the amount usually found in urine. To further evaluate the amount of pyridinium cross-links excreted through bile, we studied the stability of these compounds at the alkaline pH of bile. No effect on their stability was detected over a 6-hour incubation. The origin of these molecules in bile and the significance of this finding in the use of PYD and DPD as bone resorption markers are discussed.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 5
    Digitale Medien
    Digitale Medien
    Springer
    Calcified tissue international 58 (1996), S. 65-69 
    ISSN: 1432-0827
    Schlagwort(e): Key words: Collagen — Glycosylation — Trabecular — Cortical — Bone.
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Abstract. This study sought to evaluate whether the architecture of the matrix of cortical and trabecular bone is exactly the same. For this purpose we analyzed the extent of some posttranslational modifications of type I collagen, which is the major component of bone matrix. Ten female and 10 male 100-day-old rats were sacrificed and the content of hydroxylysine, glycosylated hydroxylysine, and pyridinium cross-links of collagen from cortical and trabecular bone was determined. The amount of each compound was expressed as a molar ratio with hydroxyproline. The collagen posttranslational modification pattern appears to be the same in both sexes but with a higher extent of differences in females compared with males. Comparing cortical and trabecular bone, the former contains a higher amount of hydroxylysine residues whereas in the latter, glycosylation of hydroxylysine is higher and pyridinium cross-link concentration is lower. Moreover, an inverse linear relationship between glycosylated hydroxylysine and pyridinium cross-links concentration was established, both for female (r =−0.455, P= 0.04) and male rats (r =−0.426; P= 0.06). This paper discusses what these findings may mean in functional terms.
    Materialart: Digitale Medien
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