Modelling of krypton-xenon separation by dynamic fixed-bed adsorption on zeolite

International audienceCurrently noble gases are separated by cryogenic distillation, which is an expensive process with safety constraints due to the cryogenic temperatures used. Adsorptive separation, such as temperature/pressure swing adsorption, is studying as it is considered as an energy, safety and cost effective alternative. Different selective materials are described in the literature from inorganic adsorbents based on physical adsorption to new metal-organic frameworks (MOFs) based on size and chemistry. This work focuses on the description of a modelling of Kr-Xe separation by selective adsorption on a chabazite zeolite in a fixed bed column

L'émotion véhiculée par le langage au service de l'apprentissage de l'orthographe

International audienceDes enfants scolarisés du CE1 au CM2 lisent et écoutent des histoires positives, négatives ou neutres se terminant par un pseudo-mot. Ils sont soumis après la présentation de toutes les histoires à une tâche de reconnaissance orthographique du pseudo-mot. Les résultats montrent un effet bénéfique de la valence émotionnelle dès le CE2 pour l'une ou l'autre des valences et généralisé aux deux valences au CM2. Cet effet est expliqué d'une part par la libération de ressources attentionnelles permise par l'automatisation des procédures de lecture et d'autre part par la mobilisation du système affectif et une plus grande richesse relative des représentations lexicales des mots chargés émotionnellement

Lack of Adiponectin Drives Hyperosteoclastogenesis in Lipoatrophic Mice.

Long bones from mammals host blood cell formation and contain multiple cell types, including adipocytes. Physiological functions of bone marrow adipocytes are poorly documented. Herein, we used adipocyte-deficient PPARγ-whole body null mice to investigate the consequence of total adipocyte deficiency on bone homeostasis in mice. We first highlighted the dual bone phenotype of PPARγ null mice: one the one hand, the increased bone formation and subsequent trabecularization extending in the long bone diaphysis, due to the well-known impact of PPARγ deficiency on osteoblasts formation and activity; on the other hand, an increased osteoclastogenesis in the cortical bone. We then further explored the cause of this unexpected increased osteoclastogenesis using two independent models of lipoatrophy, which recapitulated this phenotype. This demonstrates that hyperosteoclastogenesis is not intrinsically linked to PPARγ deficiency, but is a consequence of the total lipodystrophy. We further showed that adiponectin, a cytokine produced by adipocytes and mesenchymal stromal cells is a potent inhibitor of osteoclastogenesis in vitro and in vivo. Moreover, pharmacological activation of adiponectin receptors by the synthetic agonist AdipoRon inhibited mature osteoclast activity both in mouse and human cells by blocking podosome formation through AMPK activation. Finally, we demonstrated that AdipoRon treatment blocks bone erosion in vivo in a murine model of inflammatory bone loss, providing potential new approaches to treat osteoporosis

Roles of hydrophilin-like protein in the filamentous fungi Alternaria brassicicola

During their life cycle, fungi face adverse environmental conditions associated with alterations in water status. Phytopathogenic fungi are faced with this type of stress during the infection process, especially when they colonize seeds. Although these organisms are particularly effective to adapt to these water potential decreases, these coping mechanisms are so far very poorly described, particularly in filamentous fungi. Alternaria brassicicola is a seed-borne fungal pathogen responsible for the black spot disease on Brassicaceae plants. Alteration of Brassicaceae seed quality is one of the most damaging effects of the black spot. Beyond contribution to pathogen dissemination, the presence of the fungus on the seeds compromises seedling germination and survival. To better understand the determinism of fungus transmission to seeds, we previously established a reliable Arabidopsis-based pathosystem allowing investigations of A. brassicicola transmission to seeds. In particular, we showed that two mutants strain ∆abhog and ∆abnik exhibiting higher susceptibility to osmotic and water stress were highly impaired in seed transmission ability. Transcriptomic analyzes, carried out under different experimental in vitro conditions inducing these types of stress (addition of sorbitol or Poly Ethylene Glycol (PEG) or by incubation under low relative humidity (1% RH)), allowed us to identify additional mechanisms potentially involved in the fungal adaptive responses. In particular, these analyzes revealed a pool of over-expressed genes encoding putative proteins which share physiochemical features typical of hydrophilin-like proteins. We initiated studies of some of these hydrophilins by generating respective Knock-Out mutants. Functional studies has been carried out to determine whether these mutants were impaired in their adaptive response to water stress and other types of stress (such as oxidative stress) and whether hydrophilins are involved in pathogenicity. Additional transcriptomic assays conducted on ∆abhog and ∆abnik strain growth under sorbitol exposure revealed that numerous hydrophilins are regulated by these two genes

Identifying and Characterizing Alternative Molecular Markers for the Symbiotic and Free-Living Dinoflagellate Genus Symbiodinium

Dinoflagellates in the genus Symbiodinium are best known as endosymbionts of corals and other invertebrate as well as protist hosts, but also exist free-living in coastal environments. Despite their importance in marine ecosystems, less than 10 loci have been used to explore phylogenetic relationships in this group, and only the multi-copy nuclear ribosomal Internal Transcribed Spacer (ITS) regions 1 and 2 have been used to characterize fine-scale genetic diversity within the nine clades (A–I) that comprise the genus. Here, we describe a three-step molecular approach focused on 1) identifying new candidate genes for phylogenetic analysis of Symbiodinium spp., 2) characterizing the phylogenetic relationship of these candidate genes from DNA samples spanning eight Symbiodinium clades (A–H), and 3) conducting in-depth phylogenetic analyses of candidate genes displaying genetic divergences equal or higher than those within the ITS-2 of Symbiodinium clade C. To this end, we used bioinformatics tools and reciprocal comparisons to identify homologous genes from 55,551 cDNA sequences representing two Symbiodinium and six additional dinoflagellate EST libraries. Of the 84 candidate genes identified, 7 Symbiodinium genes (elf2, coI, coIII, cob, calmodulin, rad24, and actin) were characterized by sequencing 23 DNA samples spanning eight Symbiodinium clades (A–H). Four genes displaying higher rates of genetic divergences than ITS-2 within clade C were selected for in-depth phylogenetic analyses, which revealed that calmodulin has limited taxonomic utility but that coI, rad24, and actin behave predictably with respect to Symbiodinium lineage C and are potential candidates as new markers for this group. The approach for targeting candidate genes described here can serve as a model for future studies aimed at identifying and testing new phylogenetically informative genes for taxa where transcriptomic and genomics data are available

Controlling light with light via structural transformations in metallic nanoparticles

Abstract: A nanoparticle undergoing light-induced transformations between structural phases with different optical properties is an inheritably bistable structure and this bistability can be used to create a resonator-free optical memory element, operating at very low power levels. We experimentally demonstrate this memory functionality using a film of gallium nanoparticles, and we present a method for differentially accessing the logic state of the memory using a modulated optical probe beam. Functional nanoparticles are expected to play an important role in highly integrated photonic devices as active elements of waveguiding and switching structures. In recent experiments on reversible light-and electron beam-induced structural transformations in gallium nanoparticles [1, 2] and in particular in the observation of of solid-to-solid light-induced phase transitions in a single nanoparticulate In this paper we report on the experimental demonstration of bistable memory functionality that can be achieved in nanoparticles by engaging transformations between different structural #74509 -$15.00 US

Cell wall integrity and high osmolarity glycerol pathways are required for adaptation of Alternaria brassicicola to cell wall stress caused by brassicaceous indolic phytoalexins

Camalexin, the characteristic phytoalexin of Arabidopsis thaliana, inhibits growth of the fungal necrotroph Alternaria brassicicola. This plant metabolite probably exerts its antifungal toxicity by causing cell membrane damage. Here we observed that activation of a cellular response to this damage requires cell wall integrity (CWI) and the high osmolarity glycerol (HOG) pathways. Camalexin was found to activate both AbHog1 and AbSlt2 MAP kinases, and activation of the latter was abrogated in a AbHog1 deficient strain. Mutant strains lacking functional MAP kinases showed hypersensitivity to camalexin and brassinin, a structurally related phytoalexin produced by several cultivated Brassica species. Enhanced susceptibility to the membrane permeabilization activity of camalexin was observed for MAP kinase deficient mutants. These results suggest that the two signalling pathways have a pivotal role in regulating a cellular compensatory response to preserve cell integrity during exposure to camalexin. AbHog1 and AbSlt2 deficient mutants had reduced virulence on host plants that may, at least for the latter mutants, partially result from their inability to cope with defence metabolites such as indolic phytoalexins. This constitutes the first evidence that a phytoalexin activates fungal MAP kinases and that outputs of activated cascades contribute to protecting the fungus against antimicrobial plant metabolites

Outcome after failure of allogeneic hematopoietic stem cell transplantation in children with acute leukemia: a study by the Société Francophone de Greffe de Moelle et de Thérapie Cellulaire (SFGM-TC)

Allogeneic hematopoietic stem cell transplantation (SCT) contributes to improved outcome in childhood acute leukemia (AL). However, therapeutic options are poorly defined in case of post-transplantation relapse. We aimed to compare treatment strategies in 334 consecutive children with acute leukemia relapse or progression after SCT in a recent ten-year period. Data could be analyzed in 288 patients (157 ALL, 123 AML and 8 biphenotypic AL) with a median age of 8.16 years at transplantation. The median delay from first SCT to relapse or progression was 182 days. The treatment consisted in chemotherapy alone (n=108), chemotherapy followed by second SCT (n=70), supportive/palliative care (n=67), combination of chemotherapy and DLI (n=30), or isolated reinfusion of donor lymphocytes (DLI) (n=13). The median OS duration after relapse was 164 days and differed according to therapy: DLI after chemotherapy = 385 d, second allograft = 391d, chemotherapy = 174d, DLI alone = 140d, palliative care = 43d. A second SCT or a combination of chemotherapy and donor lymphocytes infusion yielded similar outcome (HR=0.85, p=0.53) unlike chemotherapy alone (HR 1.43 p=0.04), palliative care (HR=4.24, p<0.0001) or isolated DLI (HR=1,94, p<0.04). Despite limitations in this retrospective setting, strategies including immunointervention appear superior to other approaches, mostly in AML