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  • 1
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 62 (1993), S. 1099-1101 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: FTIR spectra reported by Brandt et al. [Solid State Commun. 81, 307 (1992)], Tischler et al. [Appl. Phys. Lett. 60, 639 (1992)], and Tsai et al. [Appl. Phys. Lett. 59, 2814 (1991), and 60, 1700 (1992)] have shown the presence of Si-H and Si-H2 lines in porous Si which Canham [Appl. Phys. Lett. 57, 1046 (1990)], Tischler and Tsai have considered essential to the observation of visible photoluminescence (PL). Hydrogen has been ascribed as a surface passivating agent which eliminates nonradiative transitions thus enabling PL to occur. Photo-oxidation has been described as replacing some of the surface passivants with oxygen, generating nonradiative transitions which quench the PL. We have markedly reduced the Si-H and Si-H2 content of anodized samples by treatment with CCl4 vapor. Comparison of the photoluminescent emission and excitation spectra for CCl4 treated and untreated samples show very similar results. Comparison of the FTIR spectra of photo-oxidized samples which exhibit no PL and as-anodized samples show the similar presence of Si-H and Si-H2. These observations suggest that neither Si-H nor Si-H2 is essential for the observation of PL in anodized Si. This result and the similarity in the behavior of porous Si with the polysilynes lead us to concur with Brandt et al. that visible PL in anodized Si is generated by the backbone of a 2D Si polymer.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Cell Biochemistry and Function 10 (1992), S. 261-266 
    ISSN: 0263-6484
    Keywords: Enterocytes ; streptozotocin-induced diabetes ; Pi uptake ; Pi efflux ; brush-border membranes ; proteins ; alkaline phosphatase ; SDS-PAGE ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The effect of chemically-induced diabetes on the handling of phosphate (Pi) by rat jejunal enterocytes has been investigated in the presence of a Na- or a choline-gradient. Pi uptake was significantly increased in both gradients. The Pi efflux rate constants for enterocytes from diabetic rats were similar to those of control rats. The effect of diabetes on both the protein and alkaline phosphatase isoenzymes of the rat small intestinal brush-border membranes was examined using SDS-PAGE. The patterns given by membranes from rats 14 days after the induction of diabetes were no different from those of controls.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Cell Biochemistry and Function 10 (1992), S. 257-260 
    ISSN: 0263-6484
    Keywords: Enterocytes ; efflux rate constant ; Pi efflux ; intracellular and extracellular Pi concentration ; extracellular pH ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The effect of variation in the intracellular and extracellular phosphate concentration on the Pi efflux across the basolateral membrane of pre-loaded enterocytes has been examined. Efflux rate constants for Pi fell from 0·89 h-1 to 0·68 h-1 as the extracellular Pi concentration was increased from 0·5 mM to 5 mM. As the intracellular Pi concentration was raised from 0·5 to 3 mM the rate constant dropped from 0·95 h-1 to 0·77 h-1. The findings are indicative of the presence of Pi-specific transporter at the basolateral membrane. The efflux rate constant of Pi at pH 7·1 was higher than that at pH 7·4 suggesting that the Pi flux across the basolateral membrane of enterocytes follows a similar pattern towards pH changes as do fluxes across the brush-border membrane.
    Additional Material: 3 Tab.
    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 22 (1984), S. 2005-2016 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In this article are described the solution properties of ampholytic ionomers obtained by the radical copolymerization of styrene with the ion-pair comonomer 3-methacrylamidopropyltrimethylammonium, 2-acrylamido-2-methylpropanesulfonate. The solution properties were studied in mixed solvents, with a good solvent for the polystyrene backbone and another for the ionic moieties, and in the individual good solvent of benzyl alcohol. The data obtained strongly support extensive intermolecular ionic interactions in solution.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
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