ADAM33, a New Candidate for Psoriasis Susceptibility

Psoriasis is a chronic skin disorder with multifactorial etiology. In a recent study, we reported results of a genome-wide scan on 46 French extended families presenting with plaque psoriasis. In addition to unambiguous linkage to the major susceptibility locus PSORS1 on Chromosome 6p21, we provided evidence for a susceptibility locus on Chromosome 20p13. To follow up this novel psoriasis susceptibility locus we used a family-based association test (FBAT) for an association scan over the 17 Mb candidate region. A total of 85 uncorrelated SNP markers located in 65 genes of the region were initially investigated in the same set of large families used for the genome wide search, which consisted of 295 nuclear families. When positive association was obtained for a SNP, candidate genes nearby were explored more in detail using a denser set of SNPs. Thus, the gene ADAM33 was found to be significantly associated with psoriasis in this family set (The best association was on a 3-SNP haplotype P = 0.00004, based on 1,000,000 permutations). This association was independent of PSORS1. ADAM33 has been previously associated with asthma, which demonstrates that immune system diseases may be controlled by common susceptibility genes with general effects on dermal inflammation and immunity. The identification of ADAM33 as a psoriasis susceptibility gene identified by positional cloning in an outbred population should provide insights into the pathogenesis and natural history of this common disease

Electron and proton transfers at diiron dithiolate sites relevant to the catalysis of proton reduction by the [FeFe]-hydrogenases

International audienceThis review focuses on electron and proton transfers involving hexacarbonyl and substituted {2Fe2S} complexes inspired from the active site of the [FeFe]-hydrogenases ([FeFe]H2ases), and on different mechanisms by which the synthetic models catalyze the reduction of protons. Selected aspects of the mechanisms proposed for the biological process on the basis of DFT calculations are also briefly presented

Activation of proton by the two-electron reduction of a di-iron organometallic complex

International audienceFe2(bdt)(CO)6 (1) (bdt = benzenedithiolate) exhibits a chemically reversible two-electronreduction at −1.27 V vs. Fc+/0 in CH3CN + Bu4NPF6 electrolyte. The increase in height of the reduction wave of complex1 upon increasing the concentration of toluenesulfonic acid (pKa ∼ 8 in CH3CN) is consistent with a catalysis of the protonreduction reaction (kcat ∼ 500 M−1 s−1). The reaction scheme, derived from the simulation of the voltammetric responses, involves the initial formation of the dianion 12− followed by two successive reactions with acid. The last protonation step is the rate determining step in the catalytic cycle. Using experiments conducted with acetic acid (pKa ∼ 23 in CH3CN), we further shown that the intermediate species 1H− is a significantly weaker base than the dianion 12−

Élaboration par pulvérisation magnétron réactive d'une couche thermochrome à base de dioxyde de vanadium. Application à la régulation passive de la température de panneaux solaires

Ce travail s'inscrit dans le cadre d'une thèse Cifre, en partenariat avec la société VIESSMANN Faulquemont SAS, dont l'objectif est d'aboutir à une couche absorbante de nouvelle génération qui vise à réguler de manière passive et réversible la température d'un capteur solaire. Cette couche absorbante est à base de dioxyde de vanadium (VO2), un matériau thermochrome qui présente une transition de phases de type semi-conducteur/métal en fonction de la température. Dans un premier temps, l'élaboration de films de VO2 à 500C sera présentée puis nous montrerons un procédé inédit et original permettant d'obtenir une phase pure VO2 à partir d'un dépôt effectué à température ambiante. L'étude en température des propriétés optiques et électriques de ces deux types de revêtements sera discutée ainsi que les effets sur la transition de phases de paramètres tels que, la taille de grains ou encore les contraintes internes. Enfin, nous étudierons les propriétés physiques du système biphasé du type VO2+V4O9 qui sous forme de couche absorbante se trouve, in fine, être très avantageux pour la régulation thermique d'un panneau solaireThis work is incorporated within the framework of a Cifre thesis with the partnership of the VIESSMANN Faulquemont SAS society to end in a new generation of absorbent layer in order to regulate the temperature of a solar cell in a passive and reversible way. This absorbent layer is based on vanadium dioxide (VO2), this thermochromic material exhibits a phase semiconductor to metal transition depending on its temperature. In a first step, the synthesis of VO2 films at 500 C will be exposed and then we will present a new process to obtain a pure VO2 phase with a film deposited at room temperature. The study in temperature of the optical and electrical properties of these two kinds of coatings will be discussed, same as the effects on the phase transition of parameters such as the grain size or the internal stresses. Eventually, we will study the physical properties of a VO2+V4O9 two-phase system as an absorbent layer which is, in fine, very beneficial for the thermal regulation of a solar panelNANCY-INPL-Bib. électronique (545479901) / SudocSudocFranceF

Catalysis of the electrochemical H2 evolution by di-iron sub-site models

cited By 201International audienceA short non-exhaustive overview of hexacarbonyl dithiolate di-iron species and of their substituted derivatives relevant to the chemistry of the di-iron sub-site of the hydrogenase enzymes is presented. Although few detailed electrochemical studies have been reported until now, we discuss the use of di-iron organometallic species as catalysts for the electrochemical reduction of protons. Finally, we propose targets for the synthesis of more efficient biomimetic catalysts. © 2004 Elsevier B.V. All rights reserved

Electrochemical proton reduction by thiolate-bridged hexacarbonyldiiron clusters

cited By 110International audienceThe reduction of Fe2(μ-SC6H4S)(CO) 6 (1) at glassy carbon electrode appears chemically reversible (E1/2 = -1.44 V vs. Fc in Bu4NPF6-CH 2Cl2, ks,h ∼ 5 × 10-3 cm s-1) and actually consists of two overlapping one-electron transfers with the second transfer slightly more favorable than the first (E 02-E01 ∼ 35 mV). Apparently, the reduction of Fe2(μ-SCH2C6H 4CH2S)(CO)6 (2) is also a two-electron process (E1/2 = -1.68 V vs. Fc in Bu4NPF6-CH 2Cl2), but 22- decomposes on the voltammetric time scale. For both 1 and 2, the electrochemical reduction of the neutral cluster generates intermediate species which further catalyze proton reduction in acid-containing electrolyte (i.e., HBF4 in Bu4NPF 6-CH2Cl2). Unfortunately voltammetry also reveals a catalytic cycle for electrochemical proton reduction either slow or complicated by side reactions. © 2003 Elsevier B.V. All rights reserved

On the electrochemistry of diiron dithiolate complexes related to the active site of the FeFe H(2)ase

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Activation of terminal alkynes at the sulfur-rich bimetallic site [MoIII2Cp2(μ-SMe)3]+: Alkyne-vinylidene conversion and C-S and C-C couplings promoted by addition of unsaturated substrates (RC≡CH, RN≡C, S=C=S).

cited By 33International audienceReactions of the bis(nitrile) compound [Mo2Cp2 (MeCN)2(μ-SMe)3](BF4) (1) with terminal alkynes in a 1:1 ratio in dichloromethane at room temperature led to the alkyne adduct [Mo2Cp2(μ-SMe)3(RCCH)] (BF4) (2: R = Tol (2a), Ph (2b), CH3C=CH2 (2c), nPr (2d), CO2Me (2e), CF3 (2f)). Compounds 2a-d were readily deprotonated with Et3N to give neutral acetylide derivatives [Mo2Cp2(μ-η1:η2- C≡CR)(μ-SMe)3] (3). Protonation of 3 afforded exclusively the vinylidene complexes [Mo2Cp2(μ-η1: η2-C=CHR) (μ-SMe)3](BF3) (4). Reaction of 1 with an excess of terminal alkyne RCCH in dichloromethane gave either the six-membered metallacycle compounds [Mo2Cp2(μ- η2:η4-CR=CHCR=CHSMe)(μ-SMe)2] (BF4) (5) or the S-methylthiophenium derivatives [Mo2Cp2(μ-η2:η4- C4H2R2SMe)(μ-SMe)2] (BF4) (6), depending on the nature of the R groups. Further reactions of the alkyne adducts 2 with isocyanide and carbon disulfide led to the vinyl-thioether complexes [Mo2Cp2(μ- η1:η3-CR=CR′-SMe)-(μSMe)2 (RNC)](BF4) (7, 8) and to their CS2 adducts [Mo2Cp2(S2C-CR′=CRSMe)(μ- SMe)2]-(BF4) (9, 10), which arise from regioselective C-S coupling. A mechanism is proposed for the formation of the cyclic thiometalla compounds 5, 9, and 10 and of the thiophenium species 6 which assigns a key intermediate role to vinyl-thioether species. The molecular structures of 3a, 4b, and 7a have been established by X-ray diffraction studies