In-situ QXAS study of sulfidation/oxidative regeneration reactions of zinc molybdate ZnMoO 4 and ZnO-MoO 3 materials

International audienceRecent technologies such as those using coal, natural gas or biomass as fuel are often facing the challenge of removing H2S impurities. Among the various existing routes for sulfur removal, the conversion of transition metal oxides into sulfides is often considered for deep gas purification. The ideal regenerative system, preventing waste generation, should combine a high affinity material towards H2S and an easy way for its regeneration into the initial oxide form. The present paper describes the reactivity of the ZnMoO4 mixed oxide material and ZnO–MoO3 oxides mixture as potential candidates for the regenerative H2S sorption process. The use of the QXAS technique allowed us to get time resolved information about both sulfidation and oxidative regeneration processes at Mo and Zn K-edges. Faced with the complexity of gas–solid reactions involving several phases, QXAS in combination with multivariate data analysis enabled us to follow the sulfidation and oxidative regeneration kinetics of both materials, with a description of the evolution of several intermediate phases. Both Mo and Zn K-edge spectroscopic data were analyzed and comparison of the evolution of ternary oxides containing the two elements proved to be an effective way for validating the results.Graphical abstract: In situ QXAS study of sulfidation/oxidative regeneration reactions of zinc molybdate (ZnMoO4) and ZnO–MoO3 material

Two novel missense mutations in FGD4/FRABIN cause Charcot-Marie-Tooth type 4H (CMT4H)

International audienceBy sequencing of the FGD4 coding sequence in a cohort of 101 patients affected by autosomal recessive demyelinating Charcot-Marie-Tooth disease (CMT), we have identified two novel missense mutations in FGD4 in two patients from consanguineous descent: p.Arg442His in an Algerian patient and p.Met566Ile in a Lebanese girl. The patients present early onset, slowly progressive CMT, with drastic reduction of nerve conduction velocities. These mutations are the second and third missense mutations characterized in FGD4. They are likely to lead to conformational changes in the PH1 and FYVE domains

Le prix de la mort

Le thème du prix de la mort de ce numéro s'inscrit dans un champ traditionnel des sciences humaines, mais l'approche quantitative le situe dans la continuité des enquêtes initiées par les historiens dans les années 1960-1970. Ces six articles étudient les pratiques d'acteurs sociaux et de corps rapportées aux offres institutionnelles et économiques, en Europe de l'Antiquité au XXe siècle. En mobilisant des sources variées avec des instruments de mesure différents, ils restituent des gradations et des comparaisons exprimables en termes d'une économie de la mort et du deuil. Au-delà des choix individuels, ils rattachent les échelles locales de la mort aux disparités socio-économiques et politiques, aux rangs, aux hiérarchies et aux fortunes, afin de prendre la mesure des valeurs économiques qui circulent autour de la mort

Behavioral and molecular exploration of the AR-CMT2A mouse model Lmna R298C/R298C

International audienceIn 2002, we identified LMNA as the first gene responsible for an autosomal recessive axonal form of Charcot-Marie-Tooth disease, AR-CMT2A. All patients were found to be homozygous for the same mutation in the LMNA gene, p.Arg298Cys. In order to investigate the physiopathological mechanisms underlying AR-CMT2A, we have generated a knock-in mouse model for the Lmna p.Arg298Cys mutation. We have explored these mice through an exhaustive series of behavioral tests and histopathological analyses, but were not able to find any peripheral nerve phenotype, even at 18 months of age. Interestingly at the molecular level, however, we detect a downregulation of the Lmna gene in all tissues tested from the homozygous knock-in mouse Lmna (R298C/R298C) (skeletal muscle, heart, peripheral nerve, spinal cord and cerebral trunk). Importantly, we further reveal a significant upregulation of Pmp22, specifically in the sciatic nerves of Lmna (R298C/R298C) mice. These results indicate that, despite the absence of a perceptible phenotype, abnormalities exist in the peripheral nerves of Lmna (R298C/R298C) mice that are absent from other tissues. Although the mechanisms leading to deregulation of Pmp22 in Lmna (R298C/R298C) mice are still unclear, our results support a relation between Lmna and Pmp22 and constitute a first step toward understanding AR-CMT2A physiopathology

Mutations in FGD4 Encoding the Rho GDP/GTP Exchange Factor FRABIN Cause Autosomal Recessive Charcot-Marie-Tooth Type 4H

Charcot-Marie-Tooth (CMT) disorders are a clinically and genetically heterogeneous group of hereditary motor and sensory neuropathies characterized by muscle weakness and wasting, foot and hand deformities, and electrophysiological changes. The CMT4H subtype is an autosomal recessive demyelinating form of CMT that was recently mapped to a 15.8-Mb region at chromosome 12p11.21-q13.11, in two consanguineous families of Mediterranean origin, by homozygosity mapping. We report here the identification of mutations in FGD4, encoding FGD4 or FRABIN (FGD1-related F-actin binding protein), in both families. FRABIN is a GDP/GTP nucleotide exchange factor (GEF), specific to Cdc42, a member of the Rho family of small guanosine triphosphate (GTP)–binding proteins (Rho GTPases). Rho GTPases play a key role in regulating signal-transduction pathways in eukaryotes. In particular, they have a pivotal role in mediating actin cytoskeleton changes during cell migration, morphogenesis, polarization, and division. Consistent with these reported functions, expression of truncated FRABIN mutants in rat primary motoneurons and rat Schwann cells induced significantly fewer microspikes than expression of wild-type FRABIN. To our knowledge, this is the first report of mutations in a Rho GEF protein being involved in CMT

miR-376a-3p and miR-376b-3p overexpression in Hutchinson-Gilford progeria fibroblasts inhibits cell proliferation and induces premature senescence

International audienc