EBSD investigation of SiC for HTR fuel particles

Xavier Bourrat : Present Address ISTO - CNRS-Université d'OrléansInternational audienceElectron back-scattering diffraction (EBSD) can be successfully performed on SiC coatings for HTR fuel particles. EBSD grain maps obtained from thick and thin unirradiated samples are presented, along with pole figures showing textures and a chart showing the distribution of grain aspect ratios. This information is of great interest, and contributes to improving the process parameters and ensuring the reproducibility of coating

Epidermolysis bullosa simplex generalized severe induces a T helper 17 response and is improved by apremilast treatment

International audienceBACKGROUND: Epidermolysis bullosa simplex generalized severe is a genetic disorder caused by mutation in KRT5 or KRT14 genes. Usually considered as a mechanical disease, recent data argue for additional inflammatory mechanisms. OBJECTIVES: The aim of this study was to assess the inflammation in the skin of patients with EBS. METHODS: A first immunohistochemical retrospective study was performed on frozen skin samples from 17 EBS-gen sev patients. A second multicenter prospective study was conducted on 10 patients with severe EBS-gen sev. Blister fluid and epidermis were processed for immunochemistry analysis and quantitative real time PCR. Cytokine expression was analyzed in blister fluid and compared with controls. RESULTS: Histological analysis showed a constant dermal perivascular CD4+ lymphocytes infiltrate in skin biopsies of blister (n=17) as well as in rubbed skin (n=5), an epidermal infiltration of neutrophils and eosinophils in 70% of cases and an increased immunostaining for CXCL9 and CXCL10 in blistering skin. High levels of Th17 cytokines were detected in lesional skin. Three adult patients with EBS-gen sev were treated with apremilast with a dramatic improvement of skin blistering and good tolerance. CONCLUSION: Our study demonstrates the importance of inflammation in EBS-gen sev patients and underlines the key role for Th17 cells in its pathogenesis. In addition, this study provides promising new therapeutic approaches for this disabling disorder. This article is protected by copyright. All rights reserved

Travelers With Cutaneous Leishmaniasis Cured Without Systemic Therapy

Guidelines recommend wound care and/or local therapy as first-line treatment for cutaneous leishmaniasis. An analysis of a referral treatment program in 135 travelers showed that this approach was feasible in 62% of patients, with positive outcome in 83% of evaluable patient

Combining Computational Prediction of Cis-Regulatory Elements with a New Enhancer Assay to Efficiently Label Neuronal Structures in the Medaka Fish

The developing vertebrate nervous system contains a remarkable array of neural cells organized into complex, evolutionarily conserved structures. The labeling of living cells in these structures is key for the understanding of brain development and function, yet the generation of stable lines expressing reporter genes in specific spatio-temporal patterns remains a limiting step. In this study we present a fast and reliable pipeline to efficiently generate a set of stable lines expressing a reporter gene in multiple neuronal structures in the developing nervous system in medaka. The pipeline combines both the accurate computational genome-wide prediction of neuronal specific cis-regulatory modules (CRMs) and a newly developed experimental setup to rapidly obtain transgenic lines in a cost-effective and highly reproducible manner. 95% of the CRMs tested in our experimental setup show enhancer activity in various and numerous neuronal structures belonging to all major brain subdivisions. This pipeline represents a significant step towards the dissection of embryonic neuronal development in vertebrates

Clinical spectrum of MTOR-related hypomelanosis of Ito with neurodevelopmental abnormalities

PURPOSE: Hypomelanosis of Ito (HI) is a skin marker of somatic mosaicism. Mosaic MTOR pathogenic variants have been reported in HI with brain overgrowth. We sought to delineate further the pigmentary skin phenotype and clinical spectrum of neurodevelopmental manifestations of MTOR-related HI. METHODS: From two cohorts totaling 71 patients with pigmentary mosaicism, we identified 14 patients with Blaschko-linear and one with flag-like pigmentation abnormalities, psychomotor impairment or seizures, and a postzygotic MTOR variant in skin. Patient records, including brain magnetic resonance image (MRI) were reviewed. Immunostaining (n = 3) for melanocyte markers and ultrastructural studies (n = 2) were performed on skin biopsies. RESULTS: MTOR variants were present in skin, but absent from blood in half of cases. In a patient (p.[Glu2419Lys] variant), phosphorylation of p70S6K was constitutively increased. In hypopigmented skin of two patients, we found a decrease in stage 4 melanosomes in melanocytes and keratinocytes. Most patients (80%) had macrocephaly or (hemi)megalencephaly on MRI. CONCLUSION: MTOR-related HI is a recognizable neurocutaneous phenotype of patterned dyspigmentation, epilepsy, intellectual deficiency, and brain overgrowth, and a distinct subtype of hypomelanosis related to somatic mosaicism. Hypopigmentation may be due to a defect in melanogenesis, through mTORC1 activation, similar to hypochromic patches in tuberous sclerosis complex

Characterization of SiC/C(B)/SiC microcomposites by transmission electron microscopy

International audienceUniform or composition graded C(B) interphases in SiC/SiC model microcomposites were characterized by transmission electron microscopy after tensile tests and thermal ageing in air. A specific method was developed to prepare thin longitudinal sections of the tested specimens. Deflection of matrix cracks occurs within the uniform C(B) interphase as long as its anisotropy remains high enough (i.e. when the boron content is not too high). It takes place close to the most anisotropic layer (i.e. that containing 8 at. % of boron) in composition graded interphases. In both cases, crack deflection path does not reach the fiber, a feature which is consistent with the good mechanical properties. After ageing in air under tensile loading beyond the proportional limit (600 °C; σ = 800 MPa), the composition graded interphase (made of five sublayers in which the boron content increases from 0 at. % near the fiber to 33 at. % near the matrix) was observed to act as a glass forming protection, the pyrocarbon sublayer (at the fibre surface) remaining unoxidized

Deposition process of laminar pyrocarbon from propane

The deposition mechanisms of smooth laminar (SL) and rough laminar (RL) pyrocarbons from propane are found to be very different, as evidenced by (i) gas phase analysis, (ii) nucleation experiments and (iii) analysis of the deposit composition and nanostructure. SL pyrocarbon results mainly from aliphatic species ; its nucleation needs surface reactive sites where chemisorption and hydrogen abstraction occur ; its growth leads to extended but highly distorted graphene layers which can enclose internal nanoporosity. RL pyrocarbon results mainly from polycyclic aromatic hydrocarbons (PAH) ; its nucleation, which does not depend on the substrate, occurs widely by physisorption of PAH ; the corresponding graphene layers are not very extended but parallel to each other and parallel to the anisotropy plane

Association organo-minérale dans les sédiments et les sols : Formation - Organisation - Propriétés

Dans la couche la plus superficielle de la planète Terre, les organismes vivants et les matières organiques qui en dérivent jouent un rôle fondamental dans la formation des phases minérales solides et conditionnent largement les propriétés des sédiments et sols. Les argiles et les carbonates, minéraux extrêmement répandus dans tous les milieux, vont permettre d'illustrer l'importance des associations organo-minérales, leurs caractères communs et leur diversité, et de présenter quelques approches pour décrire et caractériser ces matériaux complexes. Le formation et les propriétés de complexes organo-métalliques dans les sols seront également abordés. Les interactions entre les phases organiques et minérales sont multiples, ont lieu à différentes échelles spatiales et mettent en jeu des composants chimiquement très variés. La formation et les propriétés macroscopiques de telles associations résultent très généralement de processus et organisations aux échelles nanométrique à millimétrique. L'étude de l'organisation microstructurale des associations organo-minérales apparaît donc commune à des problématiques très variées. Organisation microstructurale : quelles méthodes ? La recherche de la localisation respective des composants organiques et minéraux dans les assemblages complexes peut aujourd'hui s'appuyer sur une instrumentation variée en microscopie, de l'échelle millimétrique à nanométrique. Les composants organiques visés peuvent être des microorganismes (champignons, algues, bactéries), des gels mucilagineux résultant de sécrétions extracellulaires (EPS) et de produits de dégradation des tissus et cellules, des macromolécules solubles souvent difficiles à visualiser. L'identification in situ de la nature biochimique des matières organiques est une difficulté récurrente. Les exemples présentés, microagrégats de sols, argiles, organo- et biominéraux carbonatés, illustrent les apports de telles méthodes et leurs limites. Formation des organo- et biominéraux carbonatés La matière organique intraminérale (matrice) résulte de l'assemblage, au cours du processus de précipitation du carbonate, de composés sélectionnés qui contrôlent la formation et la croissance des minéraux. Le parallélisme entre des carbonates précipités dans des mattes cyanobactériennes et les carbonates biogéniques qui constituent les tests des métazoaires (exemple de la nacre des huîtres perlières) peut être mise en évidence, tant en ce qui concerne les processus de leur genèse que leur organisation microstructurale. Les particularités biochimiques des MO impliquées permettent de distinguer des carbonates formés dans des environnements distincts. Propriétés des associations organo-minérales La formation des associations organo-minérales affecte les propriétés et le devenir des deux phases en présence. Ainsi, la stabilisation des matières organiques dans les sols et les sédiments, pour des durées pouvant excéder le siècle, serait largement due à leur association avec des minéraux : adsorption sur les argiles ou les oxydes limite leur biodisponibilité, localisation au sein d'édifices organo-minéraux limite leur accessibilité aux microorganismes. Les associations organo-minérales ont une réactivité physicochimique, vis-à-vis de polluants notamment, qui n'est pas décrite par des modèles simplement additifs