Colloque L'Enfant Combattant. Pratiques et représentations : 25-26 novembre 2010, introduction

L'Enfant Combattant, pratiques et représentations est le premier colloque du programme de l'ANR Enfance Violence Exil - acronyme EVE : introductio

Effects of confinement and crowding on folding of model proteins

We perform molecular dynamics simulations for a simple coarse-grained model of crambin placed inside of a softly repulsive sphere of radius R. The confinement makes folding at the optimal temperature slower and affects the folding scenarios, but both effects are not dramatic. The influence of crowding on folding are studied by placing several identical proteins within the sphere, denaturing them, and then by monitoring refolding. If the interactions between the proteins are dominated by the excluded volume effects, the net folding times are essentially like for a single protein. An introduction of inter-proteinic attractive contacts hinders folding when the strength of the attraction exceeds about a half of the value of the strength of the single protein contacts. The bigger the strength of the attraction, the more likely is the occurrence of aggregation and misfolding

Procedure for the Experimental Determination of a Forming Limit Curve for Usibor 1500 P

International audienceUSIBOR 1500 P® is a coated C-Mn steel, micro-alloyed with boron, with excellent processing properties in hot stamping, both in terms of formability, quenchability and surface protection, and leading to superior mechanical properties on the formed part. Arcelor Research is developing a numerical tool to support the feasibility analysis and to optimize the design of hot stamped parts made of USIBOR 1500P®. Among the numerous bricks of such a simulation methodology, formability data of the material are of primary importance as the forming analysis relies on them to make a decision in terms of feasibility. Up to now, there was no experimental procedure available in literature to determine the forming limits of hot stamping material, taking into account the specificities of this process. This paper reports about the research performed in this field. First, an efficient experimental set-up which allows varying all the desired process conditions has been developed. Several hundred Nakazima hot stamping tests have been carried out for various process parameters (stroke, velocity, friction and heat exchange) and blank para-meters (temperature, thickness and shape). The third step consisted in developing and vali-dating an accurate analysis scheme to determine the critical strain values based on the Bragard method. Finally, the critical strain values have been confirmed and comparisons with industrial parts for various process conditions have been performed. In this paper these two last steps are mainly presented

MicroRNAs as new player in rheumatoid arthritis

MicroRNAs (miRNAs) are small noncoding RNA molecules that negatively regulate gene expression at the post-transcriptional level. Currently, there are 939 mature human miRNA sequences listed in the Sanger updated miRNA registry. There are approximately 1500 predicted miRNAs in the human genome that may regulate the expression of one third of our genes. By controlling the accumulation of the target protein(s) in cells, these regulatory RNA molecules participate in key functions in many physiological networks and their deregulation has been implicated in the pathogenesis of serious human disorders, such as cancer and infection. The implication of miRNAs in immune-mediated disorders such as rheumatoid arthritis (RA) has recently emerged suggesting that miRNA-based therapeutic approaches may have a promising potential in these diseases. Here, we provide an overview of the state-of-the-art on miRNAs in RA, focusing on both systemic and local features of the pathology

Formability investigations for the hot stamping process

International audienceArcelor Research is developing a numerical tool to support the feasibility analysis and to optimize the design of hot stamped parts made of USIBOR 1500P®. To provide formability data and to feed the development of a fracture criterion, experimental hot stamping tests are carried out at Cemef (Centre for Material Forming). These hot stamping experiments are based on a modified Nakazima-type test. Results reveal that the achievable strain levels depend on process parameters (stroke, velocity, temperature, friction and heat exchange) and blank parameters (initial temperature, thickness and shape). In parallel, a numerical model of these hot stamping tests has been developed with finite element softwares (Forge2®, Forge3® and Abaqus). The numerical simulations confirm the location and the magnitude of the blank thinning. Furthermore, the numerical results are similar to the experimental measurements in terms of punch load, cooling rate and strain distribution. A formability analysis is then performed to study the influence of the blank geometry and the blank temperature on formability

Consensus mutagenesis reveals that non-helical regions influence thermal stability of horseradish peroxidase

The enzyme horseradish peroxidase has many uses in biotechnology but a stabilized derivative would have even wider applicability. To enhance thermal stability, we applied consensus mutagenesis (used successfully with other proteins) to recombinant horseradish peroxidase and generated five single-site mutants. Unexpectedly, these mutations had greater effects on steady-state kinetics than on thermal stability. Only two mutants (T102A, T110V) marginally exceeded the wild type's thermal stability (4% and 10% gain in half-life at 50 °C respectively); the others (Q106R, Q107D, I180F) were less stable than wild type. Stability of a five-fold combination mutant matched that of Q106R, the least-stable single mutant. These results were perplexing: the Class III plant peroxidases display wide differences in thermal stability, yet the consensus mutations failed to reflect these natural variations. We examined the sequence content of Class III peroxidases to determine if there are identifiable molecular reasons for the stability differences observed. Bioinformatic analysis validated our choice of sites and mutations and generated an archetypal peroxidase sequence for comparison with extant sequences. It seems that both genetic variation and differences in protein stability are confined to non-helical regions due to the presence of a highly conserved alpha-helical structural scaffold in these enzymes

La ayuda de los países neutrales en el retorno a la vida de las mujeres rescatadas del campo de Ravensbrück. El caso de las mujeres españolas

Nothing more usual than to find Spanish refugees of 1939 in the French Resistance as they continued their fight against fascism. Therefore, hundreds of Spaniards where caught in the nets of the Vichy Government and the Gestapo. They are imprisoned in the French jails (Toulouse, Montluc, Fresnes, Compiègne, etc.) alongside the French Resistant women. Both will be piled up in wagons to the camps of the Third Reich. Many ended at the women’s camp in Ravensbrück. Usually, the Spaniards were labelled “F”, “French”, because they were arrested in France. This “F” was part of the “red triangle” of the “political prisoners”. Some were even classified NN (Nacht und Nebel), i.e. called to disappear without a trace. As they were recognized by nobody (neither the French nor the Spaniards), this means: no mail, no parcels. They held on for life thanks to the links they forged randomly across blocks, satellite camps, languages, affinities... However, many died. For some of them, the release arrived in April 1944, thanks to “neutral” countries initiatives: in fact, a few Spanish women were able to slip into the Red Cross convoys transiting through Switzerland, which were initially reserved for French women. Others returned by Sweden. Others, finally, faced the apocalyptic evacuation of the camps of 1945 and the “marches of death”. We propose to study “the return to life” helps through some cases – obviously return to France since there could be no possible repatriation for these Spanish anti-fascist survivors, as the victory of the Allies did not affect General Franco’s power. After returning to France, this help continued for two or three years, in particular thanks to convalescent stays in Switzerland, Sweden and somewhere else, and thanks to one-off material contributions from the Swiss Grant (“Don suisse”) or from various organizations.Que se hallen refugiadas de 1939 en la Resistencia francesa, nada más natural: prosiguen su lucha contra el fascismo. Se cuentan por centenas las españolas atrapadas en las redadas “vichystas” y “gestapistas”. Las encarcelan con las resistentes francesas en las cárceles de Francia (Toulouse, Montluc, Fresnes, Compiègne, etc.), las hacinan en vagones destinados a los campos del III Reich. Muchas van a parar al campo de mujeres de Ravensbrück. Las españolas son catalogadas “F”, “francesas”, por haber sido detenidas en Francia. Esa “F” se inscribe en el “triángulo rojo” de las “políticas”. A algunas las clasifican “NN” (Nacht und Nebel), es decir llamadas a desaparecer sin dejar rastro. No ser reconocidas ni por el Estado francés, ni por el Estado español, eso significa: ni cartas, ni paquetes. Lo que les permitió resistir fueron los lazos que (se) tejieron al azar de los bloques, de los campos satélites, de los idiomas, de las afinidades… Pero muchas murieron. Para algunas la liberación llegó en abril de 1945, gracias a iniciativas de países neutrales. Unas cuantas pudieron deslizarse en los convoyes de la Cruz Roja reservados a las francesas que transitaron por Suiza. Otras volvieron por Suecia. Otras, por fin, sufrieron la evacuación apocalíptica de los campos de 1945 y las “marchas de la muerte”. Se estudiarán las ayudas al “retorno a la vida” a través de algunos casos –retorno a Francia ya que era imposible repatriar a España a esas supervivientes antifascistas, la victoria de los Aliados no habiendo afectado en nada el poder del general Franco. Aquellas ayudas se prologaron después de la liberación durante dos o tres años, en particular mediante estancias de convalecencia en Suiza y en Suecia, y aportes (materiales) procedentes del “Don Suisse” o de otros organismos