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New kelatorphan-related inhibitors of enkephalin metabolism: improved antinociceptive properties
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Crossed beam study of the I 2 +F 2 →IF( B )+IF( X ) reaction: Spectrum of the chemiluminescence and rovibrational distribution of IF( B )
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Presence of basic fibroblast growth factor receptors in bovine brain membranes.
No full textInternational audienceWe described a protocol for purification of bovine brain membranes suitable to study the binding of iodinated basic fibroblast growth factor (FGF) to bovine brain membrane preparation. The binding of 125I basic FGF to brain membranes reached equilibrium within 30 min at 20 degrees C, was reversible, and displaced by an excess of unlabeled basic FGF. Scatchard analysis of the data revealed that two classes of binding sites could be detected with an apparent Kd of 30 pM and a capacity of 0.24 pmol/mg of membrane proteins for the high affinity binding site and Kd of 3 nM with a capacity of 51 pmol/mg of membrane proteins for the low affinity binding site. Cross-linking experiments of labeled basic FGF to brain membrane receptor yield the formation of a single major complex with an apparent molecular mass of 170 kDa which is similar to the value obtained for the high affinity binding site for basic FGF on target cells in tissue culture. Hence these data present the first biochemical evidence suggesting that membrane purified from bovine brain contain two classes of specific binding sites for basic FGF and confirm results described with cells grown in vitro
DFT investigation on the nickel(II) catalyzed dimerization of ethylene.
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Spinal columnar liquid crystals: polymeric octasubstituted µ-oxo-(phthalocyaninato)tin( IV )
No full textInternational audienceAn octa-alkylsubstituted derivative of dihydroxo-tin(IV) phthalocyanine is shown to form columnar liquid crystals; polycondensation of the dihydroxo-tin(IV) derivative leads to a spinal columnar mesophase by formation of oxystannyl links between the macrocyclic units
Electrochemical impedance in a thin surface electrolyte layer. Influence of the potential probe location
No full textInternational audienceThe role of the potential distribution on the impedance diagram of thin layer covered electrodes has been investigated as a function of the reference tip position and layer thickness. The observed behaviour is shown to be of interest to any distributed system. An interpretation is given in the framework of the porous electrode model allowing to predict the optimal position of the potential probe
Structural evolution of very thin silicon oxide films during thermal growth in dry oxygen
No full textInternational audienceWe have studied the structural characteristics of very thin silicon oxide films thermally grown (at 930 °C, 10 Torr) in 18O enriched dry oxygen for times ranging from 0.5 to 22.5 h (corresponding to equivalent thicknesses ranging from 3.2 to 20.8 nm). Chemical etching combined with nuclear microanalysis, x-ray photoelectron spectroscopy (XPS), and reflection high-energy electron diffraction (RHEED) has been applied to the samples. A layer that is very slow to dissolve (of equivalent thickness ∼1.1 nm) was observed for oxide films grown for oxidation times of less than 1 h (equivalent thicknesses under 4.6 nm). As indicated by XPS this layer seems to be related to a structure different from what is observed for thicker films; its existence is also correlated to a structural order as seen by RHEED