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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Anatomy and embryology 199 (1999), S. 519-527 
    ISSN: 1432-0568
    Keywords: Key words Morphology ; Embryo culture ; Lipid droplet ; Development
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  The ultrastructure of bovine morulae and blastocysts developed from in vitro-matured and -fertilized oocytes in a serum-supplemented medium was compared with that of morulae and blastocysts collected non-surgically from superovulated cows. In the in vivo-derived morulae, two characteristic cells types could be identified by the electron-density of their cytoplasm and by their ultrastructural features. One type appeared light in color with low electron-dense cytoplasm. These cells were located in the peripheral layer of the cluster of blastomeres, possessed numerous cellular organelles such as mitochondria and Golgi apparatus and had microvilli projecting into the perivitelline space. The other cell type was distinguished by cytoplasm that stained more densely than that of the lighter-appearing cells. The darker-appearing cells generally possessed fewer organelles than the lighter cells, but many lysosome-like structures were present in the cytoplasm. The in vitro-developed morulae also contained two types of cells similar to those observed in the in vivo morulae. However, most of the in vitro-developed cells possessed numerous lipid droplets and contained fewer lysosome-like structures than the cells of the in vivo-derived morulae. The blastocysts, both in vivo and in vitro, showed a clear differentiation of trophoblast cells and inner cell mass (ICM)-cells. In the in vivo-derived blastocyst, the apical membrane of trophoblast cells was covered with large, numerous microvilli and well-developed junctional complexes were observed. Lipid droplets were present in the cytoplasm of trophoblast and ICM-cells but were not abundant. In vitro-developed blastocysts showed less well-developed junctional complexes between trophoblast cells, less well-developed apical microvilli on the trophoblast cells, and contained large numbers of lipid droplets. This accumulation of lipid droplets was higher in the trophoblast cells than in the ICM-cells. The zonae pellucidae of in vitro-developed embryos were thinner than that of the in vivo-derived embryos. This study demonstrates conspicuous differences in the ultrastructural features between the in vivo-derived and in vitro-developed embryos, suggesting that the ultrastructure may reflect the various physiological anomalies observed in previous studies.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-0827
    Keywords: PTHrP ; Articular cartilage ; Chondrocyte ; Development
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract Expression and localization of parathyroid hormone-related protein (PTHrP) in rat articular cartilage during fetal and postnatal periods were investigated by immunohistochemistry and in situ hybridization. PHTrP displayed distinct distribution and intensity of staining at different ages. In fetal (18-day-old) and young (3-week-old) rats, articular chondrocytes expressed abundant PTHrP throughout the entire thickness of cartilage. In contrast, in 60-week-old rats, PTHrP was expressed in a few articular chondrocytes of superficial and middle layers. Regulation of PTHrP and PTH/PTHrP receptor mRNA was also studied in cultured rat articular chondrocytes. Northern blot analysis revealed that both transforming growth factor-β (TGF-β), an important stimulator for chondrocyte proliferation and differentiation, and 10% fetal bovine serum (FBS) stimulated the expression of PTHrP mRNA with down-regulation of its receptor mRNA. In contrast, 12-O-tetradecanoylphorbol-13-acetate (TPA) down-regulated the expression of receptor without changes of PTHrP mRNA level. These results suggest that the changes in abundance and localization of PTHrP and its receptor may be directly involved in the cell growth and differentiation of articular cartilage.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 18 (1980), S. 1203-1211 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The acid-catalyzed stepwise polymerization of 1,1-diphenylethylene derivatives, p-di(1-phenylvinyl) benzene, bis[p-(1-phenylvinyl)phenyl]methane, 1,2-bis[p-(1-phenylvinyl)phenyl]ethane, bis[p-(1-phenylvinyl)phenyl]ether, and bis[p-(1-phenylvinyl)phenyl]sulfide produced selectively indanic-unit-containing polymers in pertinent conditions. Their molecular weights (M̄n) were in the 1600-15, 700 region after the fractionation in hot ethnol. Melting points were in the 214-281°C region. They dissolved fairly well in conventional solvents like benzene, tetrahydrofuran, and carbon tetrachloride. According to TGA they started to decompose at 397-432°C and showed 10% weight loss at 478-502°C in air at a heating rate of 5°C/min. Focusing on the thermostability, we report on their physical properties.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 18 (1980), S. 515-526 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The polymers containing units of 1,1,3,3-tetraphenylbut-1-ene [unit (I)] and/or units of 3-methyl-1,1,3-triphenylindan [unit (II)] in the main chain were prepared by acid-catalyzed dimerization of 1,1-diphenylethylene applied to its bifunctional derivatives, for example bis[p-(1-phenylvinyl)phenyl]methane. The structure of yielded polymers depended on catalyst, solvent, temperature, and the molar ratio between the catalyst and the monomer. The molecular weight of polymer having unit (I) was determined by the equilibrium existing between 1,1-diphenylethylene moiety and unit (I). It was shown clearly by gel permeation chromatography that the molecular weight of polymer having unit (II) grew further after the equilibrium mentioned above had been accomplished. The mechanism of the polymerization is discussed.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 18 (1980), S. 2061-2070 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Polymerization of 1,3-bis(p-vinylphenyl) propane (St-C3-St) was investigated by using radical and anionic initiators. Radical polymerization yielded linear polymer with pendant styryl groups in pertinent conditions without gelation. Anionic polymerization with n-butyllithium and sodium naphthalene produced insoluble polymers that, according to infrared (IR) spectroscopy, had no cyclized units. On the other hand, phenylmagnesium bromide gave soluble polymer in HMPA-benzene mixed solvent. Zero-valent nickel catalyst also gave soluble polymer. The soluble polymers could be analyzed by several spectroscopies, and it was confirmed that those obtained by anionic and coordination polymerization had no [3.3]paracyclophane units in the main chain. From these results it was concluded that cationic propagation could be assumed if the polymer Of St-C3-St contained [3.3]paracyclophane units in the main chain.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 18 (1980), S. 2071-2084 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The thermal and photoinduced polymerization of 1,3-bis(p-vinylphenyl)propane was carried outby using tetracyanoethylene as a strong electron acceptor in several solvents. This cyclopolymerization produced polymer that contained [3.3]paracyclophane units in the main chain. The solvent and additive effect of polymerization inhibitors as well as the polymer structure suggest clearly that both polymerization proceeded in a cationic mechanism.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 19 (1981), S. 3257-3268 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The compound 1,3-bis(4-vinylnaphthyl)propane was prepared by a convenient dehydration of 1,3-bis[4-(1-hydroxyethyl)naphthyl]propane. The structure was confirmed by nuclear magnetic resonance (NMR) spectroscopy. The monomer was polymerized by antimony pentachloride, tin tetrachloride, titanium tetrachloride, or boron trifluoride etherate at 0°C in toluene, 1,2-dichloroethane, or a mixed solvent of 1,2-dichloroethane and nitromethane. Most of runs except for antimony pentachloride-catalyzed ones gave mainly benzene-soluble polymers. The structures of the polymers were studied by several spectroscopic methods. Comparison of NMR and fluorescence spectroscopic data of the polymers with those of syn-and anti-[3.3](1,4)napthalenophane was especially valuable in leading to the conclusion that they were cyclopolymers containing predominantly syn-[3.3]-(1,4)naphthalenophane units in the main chain.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 28 (1983), S. 3671-3679 
    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: The novel reactive antioxidants based on tetrazoles that are stable at room temperature and convertible into the highly reactive nitrileimines by pyrolysis were prepared and the reactivity for carbon-carbon double bonds was evaluated. Antioxidants, i.e., 2-substituted phenyl-5-(3′,5′-di-tert-butyl-4′-hydroxyphenyl)tetrazoles (PHPT) were prepared with the reaction of p-toluenesulfonylhydrazone of 3,5-di-tert-butyl-4-hydroxybenzaldehyde and substituted phenyl diazonium chloride in a mixed solvent of pyridine, ethanol, and water at -10°C to -20°C in 31-61% yields. To evaluate the reactivities of PHPT for carbon-carbon double bonds, m-chloro-substituted PHPT was pyrolyzed in an excess of styrene at 160-170°C for 0.5 h to give the 1-(3′-chlorophenyl)-3-(3″,5″-di-tert-butyl-4″-hydroxyphenyl)-5-phenyl-2-pyridazoline in a 44.1% yield by 1,3-dipolar addition reaction of the nitrileimine formed from the m-chloro-substituted PHPT. The thermogravimetric analysis of a mixture of proton isomer of PHPT and liquid polybutadiene showed that PHPT attached to liquid polybutadiene with an accompanying evolution of nitrogen.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 29 (1984), S. 89-98 
    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: The chemical reactivities of novel reactive antioxidants based on tetrazoles for carbon-carbon double bonds of liquid polybutadiene and their antioxidation activities toward isoprene rubber were evaluated. These antioxidants, i.e., 2-substituted phenyl-5-(3′,5′ -di-tert-butyl-4′-hydroxyphenyl)tetrazoles (PHPT), were pyrolyzed in liquid polybutadiene at 160-170°C for 30 min to attach to rubber in extents of 61-85% of the nitrileimines formed from PHPT by 1,3-dipolar addition reaction. The reactivities of PHPT followed the order p-Cl 〉 m-Cl 〉 H 〉 p-CH3 〉 m-CH3, p-OC2H5, suggesting that PHPT reacts with diene rubber in electrophilic reaction and p-derivatives exhibit higher contents of binding than m-derivatives due to steric hindrance. From oxygen absorption data, the antioxidation activities of PHPT for isoprene rubber vulcanizates followed the order m-Cl, m-CH3 〉 H, p-Cl, p-Cl, p-CH3 〉 p-OC2H5. Isoprene rubber vulcanizates, obtained after pretreatment with PHPT by heating, were extracted with acetone, followed by aging to show that there was good retention and appreciable antioxidation activities of PHPT, especially, p-CH3 and p-Cl substituted PHPT.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 30 (1985), S. 4201-4201 
    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
    Type of Medium: Electronic Resource
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