Seasonal Fluctuations of Vegetative Storage Proteins and Starch Concentrations in Stolons of Trifolium Repens L.

The seasonal pattern of nitrogen, starch and vegetative storage protein (VSP) concentrations was studied in the stolons of two Trifolium repens L. genotypes (cv Aran and Rivendel). Maximum concentrations of starch were found in summer months; its hydrolysis occurred in winter, at the time, where VSP and nitrogen were accumulated. The decrease of nitrogen and VSP concentrations occurred during spring, and an inverse relationship was found between VSP concentrations in stolons and mean temperatures. The causal implications of starch and VSP availability on spring regrowth potential are discussed in relation with regulatory mechanism inducing VSP synthesis

Challenge of Xenotransplantation in Pediatric Heart Transplantation

Although surgical techniques have progressively improved in the field of congenital heart disease (CHD), even such as hypoplastic left heart syndrome, pediatric heart transplantation is the most effective surgical option for complex CHD and cardiomyopathy with severe heart failure. However, even now, donor heart availability has been poor in children. Although technologies for ventricular assist device (VAD) have been progressing even in children, VAD cannot grow as the pediatric recipient grows. Therefore, pediatric cardiac xenotransplantation has a great possibility to save and grow children with end-stage heart failure. In this chapter, I would like to introduce the first pediatric baboon-to-human heart transplantation and its basic animal experiments done by Bailey’s group and the following attempts for pediatric cardiac orthotopic xenotransplantation (rhesus monkey-to-baboon and pig-to-primate combination)

Probing warped extra dimension via gg -> h and h -> gamma gamma at LHC

The processes gg -> h and h -> gamma gamma are of paramount importance in the context of Higgs search at the LHC. These processes are loop driven and hence could be sensitive to the presence of any new colored fermion states having a large coupling with the Higgs. Such a scenario arises in a warped extra dimensional theory, where the Higgs is confined to the TeV brane and the hierarchy of fermion masses is addressed by localizing them at different positions in the bulk. We show that the Yukawa coupling of the Higgs with the fermion Kaluza-Klein (KK) states can be order one irrespective of their zero mode masses. We observe that the gg -> h and h -> gamma gamma rates are substantially altered if the KK states lie within the reach of LHC. We provide both intuitive and numerical comparison between the RS and UED scenarios as regards their quantitative impact in such processes.Comment: v3: 7 pages, 3 figs. Further clarifications added, matches version published in Phys Lett

Recurrence of Stachybotrys chartarum during mycological and toxicological study of bioaerosols collected in a dairy cattle shed

International audienceAgricultural occupations associated with animal breeding and the processing of animal materials in confinement systems could potentially lead to bioaerosol exposures. Moulds and mycotoxins could be constituents of bioaerosols and should be studied because of their possible involvement in respiratory diseases and cancers. In order to characterize the fungal contamination of the indoor air in a dairy barn, bioaerosols were collected during 20 days in a cattle farm located in Normandy (France). Mycobiota, mycotoxins and the mutagenicity of bioaerosols were studied. The toxigenic ability of Aspergillus flavus group and Aspergillus fumigatus isolates was also evaluated in vitro. The prevalent airborne moulds were from the following potentially toxigenic species: Aspergillus flavus group, Aspergillus fumigatus, Penicillium chrysogenum, Stachybotrys chartarum, and the allergenic species Ulocladium chartarum, Cladosporium cladosporioides. In comparison with harvesting, grain handling or broiler breeding, the concentrations of viable moulds were lower in the cattle shed. Seasonal variations in levels of several species were also observed. This study revealed that aflatoxins were detected in bioaerosols and, for the first time, showed that farmers are possibly exposed to Stachybotrys chartarum during routine barn work. Moreover, the finding of mutagenicity from bioaerosols needs further investigations on bioaerosol composition

Etudes éxprimentale de mélanges thermoplastiques/poudrettes de pneumatiques usagés

L'insertion de poudrettes (< 1 mm) de pneumatiques usagés (PUNR) issues de broyage dans une matrice thermoplastique (PP) est une voie de valorisation. Après formulation du mélange compatibilisé pour cinq taux de PUNR de 5% à 25%, des essais de traction ont été réalisés à trois vitesses de déformation (10-4, 10-3, 10-2 s-1). Des observations post-mortem (MEB et tomographie) permettent de comprendre les modes d'endommagement des éprouvettes. Les modèles micromécaniques, basés sur les opérateurs interfaciaux, sont utilisés pour identifier les critères d'endommagement de ce type de matériaux

An homogenization-based hyperelastic damage model: formulation and application to an EPDM/PP composite

The present Note concerns the formulation, implementation and a first application of a micromechanically based hyperelastic damage model. The approach is based on the second order homogenization method proposed by Lopez-Pamies and Ponte Castañeda (2000) for hyperelastic composites and recently developed by Lopez-Pamies and Ponte Castañeda (2007) in the case of porous elastomers. We first implement the method and proceed to its verification by comparison with Finite Element simulations on a unit cell. Taking advantage of this validation and by using standard thermodynamics arguments, we propose an hyperelastic damage model founded on voids growth phenomena. Finally, we provide an example of validation of the model by comparison with experimental data obtained on an EPDM/PP composite

Comportement macroscopique d'un élastomère renforcé : modélisations micro-macro et validation

Dans cette étude, nous proposons l'évaluation d'un modèle d'homogénéisation non linéaire appliqué aux composites hyperélastiques à microstructure aléatoire. Cette modélisation repose sur une mise en oeuvre, dans un contexte 3D, de la méthode du second ordre introduite par Ponte Castañeda & Tiberio (2000). Nous rappelons d'abord les principes de base de la méthode. Puis, nous étudions le cas d'un composite biphasé, constitué d'une matrice hyperélastique renforcée par des particules sphériques déformables. L'implémentation numérique du modèle micromécanique est discutée et les résultats obtenus sont présentés afin de démontrer l'effet de renforcement des particules. Afin de fournir une évaluation rigoureuse du modèle proposé, des calculs par éléments finis sur une cellule de base sont réalisés pour être comparés aux prédictions du modèle d'homogénéisation. Enfin, une confrontation aux données expérimentales montre la nécessité d'une prise en compte de phénomènes d'endommagement dans les modélisations ultérieures