Browsing by Author "DIAZ, F"

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    CHANGE WITH TIME OF THE PROPERTIES OF POLY(SELENO-P-NAPHTHALENE DIAMINE) DOPED WITH CHLORINE
    (ELSEVIER SCI LTD, 1995) BERNEDE, JC; SAFOULA, G; MOLINIE, P; GODOY, A; MHARZI, H; CONAN, A; DIAZ, F; TREGOUET, Y
    After synthesis, poly(seleno-p-arylene diamine) has been doped with chlorine. X-ray photoelectron spectroscopy (XPS) and electron spin resonance (ESR) have been carried out on the doped powder. The changes in the experimental results with storage time have been systematically analyzed. It is observed that, relative to carbon, the atomic percentage of oxygen increases with time while the signals of N, Cl and Se decrease. The changes in the N1s and Se3d spectra show that the polymer is progressively decomposed by chlorine. This decomposition is in good agreement with the change in the ESR signal. These modifications can explain the decrease in conductivity with increasing storage time.
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    EVOLUTION WITH TIME OF PROPERTIES OF THE POLYTETRABROMO-P-PHENYLENEDISELENIDE DOPED WITH AN HALOGEN (CL OR I)
    (EDITIONS SCIENTIFIQUES ELSEVIER, 1994) BERNEDE, JC; GODOY, A; MOLINIE, P; SAFOULA, G; MHARZI, H; DIAZ, F; CONAN, A
    PBrPDSe has been doped by chlorine or iodine. The samples have been studied by X ray photoelectron spectroscopy (XPS), electron spin resonance (E.S.R.) and with a scanning electron microscope equiped with an electronic microprobe. Conductivity measurements have also been performed on pressed pellet samples.
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    NONNEURONAL ENDOGENOUS GABA EFFLUX FROM THE RAT OVIDUCT
    (1993) FORRAY, MI; HIDALGO, P; DIAZ, F; BELMAR, J
    The subcellular distribution of Gamma-aminobutyric acid (GABA) was studied in the rat oviduct. The highest content of GABA was found in the soluble fraction. The effect of chemical stimulation of the endogenous GABA efflux from the rat oviduct was examined. High K+ concentrations could not induce elevation of the GABA efflux. Instead, a continuous spontaneous GABA efflux without change for long periods of time was observed. The total GABA content and GABA concentration were determined in the rat oviduct on days 1, 5, 10, 15, 30, 35 and 40 of the postnatal period and also during the estrous cycle. During postnatal development the GABA levels increase gradually with time reaching at prepuberal age a concentration similar to that found in diestrous rats. In the estrous cycle both GABA content and GABA concentration reached the highest value in the proestrous and the lowest value in the estrous phase. These findings support the hypothesis that GABA efflux may be modulated by the changes in oviductal fluid volume during the estrous cycle.
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    SYNTHESIS AND CHARACTERIZATION OF LIQUID-CRYSTAL POLYMERS WITH OLIGOSILOXANE SPACERS
    (1993) DIAZ, F; TAGLE, LH; VALDEBENITO, N; AGUILERA, C
    Diesters from 4-vinylbenzoic acid and biphenols with structural mesogenic characteristics were synthesized and interconnected by siloxane spacers with different lengths. Polymers were characterized by i.r., H-1 n.m.r. and elemental analysis. Thermal properties were studied by d.s.c. and polarized light microscopy.