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Role of Si-H and Si-H2 in the photoluminescence of porous Si (1993)

Lavine, J. M. ; Sawan, S. P. ; Shieh, Y. T. ; [weitere]

Woodbury, NY : American Institute of Physics (AIP)

Applied Physics Letters 62 (1993), S. 1099-1101

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ISSN: 1077-3118

Quelle: AIP Digital Archive

Thema: Physik

Notizen: 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.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1063/1.108754

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Digitale Medien

Effect of streptozotocin-induced diabetes on the handling of phosphate by the rat small intestine (1992)

Al-Sawan, S. ; Skillen, A. W.

New York, NY [u.a.] : Wiley-Blackwell

Cell Biochemistry and Function 10 (1992), S. 261-266

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ISSN: 0263-6484

Schlagwort(e): Enterocytes ; streptozotocin-induced diabetes ; Pi uptake ; Pi efflux ; brush-border membranes ; proteins ; alkaline phosphatase ; SDS-PAGE ; Chemistry ; Biochemistry and Biotechnology

Quelle: Wiley InterScience Backfile Collection 1832-2000

Thema: Biologie , Medizin

Notizen: 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.

Zusätzliches Material: 4 Ill.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1002/cbf.290100409

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Digitale Medien

Phosphate efflux from jejunal enterocytes of the rat: Effect of phosphate concentration gradient and pH (1992)

Al-Sawan, S. ; Skillen, A. W.

New York, NY [u.a.] : Wiley-Blackwell

Cell Biochemistry and Function 10 (1992), S. 257-260

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ISSN: 0263-6484

Schlagwort(e): Enterocytes ; efflux rate constant ; Pi efflux ; intracellular and extracellular Pi concentration ; extracellular pH ; Chemistry ; Biochemistry and Biotechnology

Quelle: Wiley InterScience Backfile Collection 1832-2000

Thema: Biologie , Medizin

Notizen: 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.

Zusätzliches Material: 3 Tab.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1002/cbf.290100408

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Digitale Medien

Solution behavior of ampholytic styrene ionomers (1984)

Salamone, J. C. ; Tsai, C. C. ; Anwaruddin, Q. ; [weitere]

New York : Wiley-Blackwell

Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 2005-2016

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ISSN: 0360-6376

Schlagwort(e): Physics ; Polymer and Materials Science

Quelle: Wiley InterScience Backfile Collection 1832-2000

Thema: Chemie und Pharmazie

Notizen: 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.

Zusätzliches Material: 9 Ill.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1002/pol.1984.170220906

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