In\'egalit\'es de Poincar\'e cin\'etiques

In this note we prove Poincar\'e type inequalities for a family of kinetic equations. We apply this inequality to the variational solution of a linear kinetic model

Le Cœur d'amour épris

Photo CAHD Ils ont vingt, trente ou cinquante ans. Ils sont comédiens, danseurs, chanteurs, musiciens, bref : artistes. Ils mettent en scène les personnages de La mouette de Tchekhov ou de Bérénice de Racine, la musique de Bach, de Mozart, de Bizet, les chansons de Piaf, Trenet, Claude François, Rita Mitsouko. Tour à tour, ils passent de la fanfare au tango, d'une ambiance jazzy à la solennité d'un quatuor à cordes. Ils aspirent un instant la gravité, et la joie la séquence d'après. Et ils ai..

Cirque Plume

Membre fondateur et co-directeur du Cirque Plume, musicien, jongleur, il a mis en scène tous les spectacles de la compagnie. Bernard Kudlak Photo Yves Perton Coulisses : Avez-vous le souvenir de moments qui ont déclenché l'envie de faire ce métier ? Bernard Kudlak : Le premier souvenir, c'est la vision, en 1967 ou 68, du film de Tarkovski Andreï Roublev, qui m'a ouvert un univers insoupçonné jusqu'alors. Cette référence est restée toujours marquante. Ensuite, l'envie de faire cette forme de ..

Laurence Sémonin

Toute la Franche-Comté connaît le personnage, à l'accent et au franc-parler délicieusement régionaux, grâce auquel Laurence Sémonin, née à Morteau, ex-institutrice aux Arces, est devenue « artiste » et célèbre dans deux spectacles : La Madeleine Proust en forme en 1982, et La Madeleine Proust à Paris en 87. Elle jouera à la Maison du Peuple de Belfort les 19 et 20 février 1999, à Villers-le-lac les 20 et 21 mai et également à Lons-le-saunier à une date non encore fixée. Laurence Sémonin Phot..

Local approach to fracture based prediction of the ΔT56J and ΔTKIc 100 shifts due to irradiation for an A508 pressure vessel steel

International audienceNuclear pressure vessel steels are subjected to irradiation embrittlement which is monitored using Charpy tests. Reference index temperatures, such as the temperature for which the mean Charpy rupture energy is equal to 56 J (T56J), are used as embrittlement indicators. The safety integrity evaluation is performed assuming that the shift of the nil-ductility reference temperature RTNDT due to irradiation is equal to the shift of T56J. A material model integrating a description of viscoplasticity, ductile damage and cleavage brittle fracture is used to simulate both the Charpy test and the fracture toughness test (CT geometry). The model is calibrated on the Charpy data obtained on an unirradiated A508 Cl.3 steel. It is then applied to irradiated materials assuming that irradiation affects solely hardening. Comparison with Charpy energy data for different amounts of irradiation shows that irradiation possibly also affects brittle fracture. The model is then applied to predict the fracture toughness shifts (ΔTKIc,100) for different levels of irradiation

Local approach to fracture based prediction of the ∆T56J and ∆T K1C100 shifts due to irradiation for an A508 pressure vessel steel

International audienceA material model integrating a description of viscoplasticity, ductile damage and brittle fracture is used to simulate both the impact (Charpy) test and the toughness (CT) fracture test. The model is calibrated on the Charpy data obtained on an unirradiated A508 Cl.3 steel. It is then applied to irradiated material assuming that irradiation affects solely hardening. Comparison with Charpy energy data for different amounts of irradiation shows that irradiation probably also affects brittle fracture. The model is then used to predict the DTKIc100 shifts for different levels of irradiation

A comprehensive view of nitrite reductases

The authors acknowledge the support of the research centers Applied Molecular Biosciences Unit-UCIBIO, which is co-financed by the ERDF under the PT2020 Partnership Agreement (POCI-01-0145-FEDER-007728). CMS acknowledges support from Project LISBOA-01-0145-FEDER-007660 (Microbiologia Molecular, Estrutural e Celular) funded by FEDER funds through COMPETE2020 – Programa Operacional Competitividade e Internacionalização (POCI). Publisher Copyright: © 2022 Elsevier B.V.The last years have witnessed a steady increase of social and political awareness for the need of studying, monitoring, and controlling several anthropological activities that are dramatically impacting the environment and human health. The increasing turnover rates of the nitrogen cycle across the Planet are of major concern, so the understanding of the biological, chemical, and physical processes associated with the biogeochemical nitrogen cycle has been attracting the attention of several scientific disciplines. For many years, the primary focus has been the so-called “dissimilatory reduction of nitrate”, which refers to the stepwise conversion of nitrate into molecular nitrogen, closely followed by the assimilatory nitrate reduction pathway, which allow nitrogen incorporation into biomolecules. The contribution of bioinorganic chemists to better understand the enzymology underlying these two branches of the N-cycle has been remarkable. The constant development of mechanistic, structural, and biological tools has been keeping this bioinorganic chemistry field very active, making it a highly relevant research area still today. In this paper, we review the state-of-the-art in both dissimilatory and assimilatory nitrite reducing enzymes, highlighting the structural peculiarities of the different metalloenzymes involved in this step.publishersversionpublishe

Transferability of cleavage fracture parameters between notched and cracked geometries

International audienceThe present study investigates the temperature ...

Evidence for modulation of the rate of intramolecular electron transfer through nitrite binding to the type 2 copper center

Eur. J. Biochem. 271, 2361–2369 (2004)The nitrite reductase (Nir) isolated from Pseudomonas chlororaphis DSM 50135 is a blue enzyme, with type 1 and type 2 copper centers, as in all copper-containing Nirs described so far. For the first time, a direct determination of the reduction potentials of both copper centers in a Cu-Nir was performed: type 2 copper (T2Cu), 172 mV and type 1 copper (T1Cu), 298 mV at pH 7.6. Although the obtained values seem to be inconsistent with the established electrontransfer mechanism, EPR data indicate that the binding of nitrite to the T2Cu center increases its potential, favoring the electron-transfer process. Analysis of the EPR spectrum of the turnover form of the enzyme also suggests that the electron-transfer process between T1Cu and T2Cu is the fastest of the three redox processes involved in the catalysis: (a) reduction of T1Cu; (b) oxidation of T1Cu by T2Cu; and(c) reoxidation of T2Cu by NO2 –. Electrochemical experiments showthat azurin from the same organism can donate electrons to this enzyme