First principle energies of binary and ternary phases of the Fe–Nb–Ni–Cr system

We present first principles enthalpies of formation and lattice parameters of iron, nickel, chromium and niobium alloys. Some of these results have been partially used in a recent assessment of the Fe–Ni–Cr–Nb quaternary phase diagram. Emphasis has been put on the fcc (A1) and bcc (A2) unary structures, the X3Y-D022, -L12, -D03, -D0a, X2Y-C14(MgZn2), -C15(MgCu2) and -C36 (MgNi2) Laves and X7Y6-D85 (μ) binary phases, and the X8Y4Z18-D8b (σ) ternary phase. We employed the state of the art to compute their properties by means of the DFT (PBE functional and PAW pseudo potentials). A comparison with experimental and theoretical data is also provided

The SuperCam Instrument Suite on the Mars 2020 Rover: Science Objectives and Mast-Unit Description

On the NASA 2020 rover mission to Jezero crater, the remote determination of the texture, mineralogy and chemistry of rocks is essential to quickly and thoroughly characterize an area and to optimize the selection of samples for return to Earth. As part of the Perseverance payload, SuperCam is a suite of five techniques that provide critical and complementary observations via Laser-Induced Breakdown Spectroscopy (LIBS), Time-Resolved Raman and Luminescence (TRR/L), visible and near-infrared spectroscopy (VISIR), high-resolution color imaging (RMI), and acoustic recording (MIC). SuperCam operates at remote distances, primarily 2-7 m, while providing data at sub-mm to mm scales. We report on SuperCam's science objectives in the context of the Mars 2020 mission goals and ways the different techniques can address these questions. The instrument is made up of three separate subsystems: the Mast Unit is designed and built in France; the Body Unit is provided by the United States; the calibration target holder is contributed by Spain, and the targets themselves by the entire science team. This publication focuses on the design, development, and tests of the Mast Unit; companion papers describe the other units. The goal of this work is to provide an understanding of the technical choices made, the constraints that were imposed, and ultimately the validated performance of the flight model as it leaves Earth, and it will serve as the foundation for Mars operations and future processing of the data.In France was provided by the Centre National d'Etudes Spatiales (CNES). Human resources were provided in part by the Centre National de la Recherche Scientifique (CNRS) and universities. Funding was provided in the US by NASA's Mars Exploration Program. Some funding of data analyses at Los Alamos National Laboratory (LANL) was provided by laboratory-directed research and development funds

First principle energies of binary and ternary phases of the Fe–Nb–Ni–Cr system

This is an author-deposited version published in: http://oatao.univ-toulouse.fr/ Eprints ID: 5546 To cite this version: Connétable, Damien and Mathon, Muriel and Lacaze, Jacques First principle energies of binary and ternary phases of the Fe-Nb-Ni-Cr system. (2011) Calphad, vol. 35 (n° 4 a b s t r a c t We present first principles enthalpies of formation and lattice parameters of iron, nickel, chromium and niobium alloys. Some of these results have been partially used in a recent assessment of the Fe-Ni-Cr-Nb quaternary phase diagram. Emphasis has been put on the fcc (A1) and bcc (A2) unary structures, the X 3 Y-D0 22 , -L1 2 , -D0 3 , -D0 a , X 2 Y-C14(MgZn 2 ), -C15(MgCu 2 ) and -C36 (MgNi 2 ) Laves and X 7 Y 6 -D8 5 (µ) binary phases, and the X 8 Y 4 Z 18 -D8 b (σ ) ternary phase. We employed the state of the art to compute their properties by means of the DFT (PBE functional and PAW pseudo potentials). A comparison with experimental and theoretical data is also provided

Calphad-type assessment of the FeNbNi ternary system

This paper presents a Calphad-type thermodynamic database for the FeNbNi system. The stable phases in this ternary system are liquid, fcc_A1, bcc_A2, C14 Laves, D0a, D85 and L12_fcc but we took also into account the C15 Laves and the metastable D022 phase because of their engineering interest. Available optimizations of the unary and binary systems were selected from the literature with the constraint that the Gibbs energy descriptions must be compatible. The only amendment needed to the selected assessments concerned the parameters for the D85 in the FeNb system. In addition, ab-initio calculations have been performed using the VASP in order to help with estimating enthalpies of formation of some binary end members of the intermetallic compounds. The optimization of the FeNbNi ternary system was performed using mostly experimental data available in the literature

Hippocampal and neocortical BRAF mutant non‐expansive lesions in focal epilepsies

International audienceAbstract Objective Mesial Temporal Lobe Epilepsy‐associated Hippocampal Sclerosis (MTLE‐HS) is a syndrome associated with various aetiologies. We previously identified CD34‐positive extravascular stellate cells (CD34+ cells) possibly related to BRAF V600E oncogenic variant in a subset of MTLE‐HS. We aimed to identify the BRAF V600E oncogenic variants and characterise the CD34+ cells. Methods We analysed BRAF V600E oncogenic variant by digital droplet Polymerase Chain Reaction in 53 MTLE‐HS samples (25 with CD34+ cells) and nine non‐expansive neocortical lesions resected during epilepsy surgery (five with CD34+ cells). Ex vivo multi‐electrode array recording, immunolabelling, methylation microarray and single nuclei RNAseq were performed on BRAF wildtype MTLE‐HS and BRAF V600E mutant non‐expansive lesion of hippocampus and/or neocortex. Results We identified a BRAF V600E oncogenic variant in five MTLE‐HS samples with CD34+ cells (19%) and in five neocortical samples with CD34+ cells (100%). Single nuclei RNAseq of resected samples revealed two unique clusters of abnormal cells (including CD34+ cells) associated with senescence and oligodendrocyte development in both hippocampal and neocortical BRAF V600E mutant samples. The co‐expression of the oncogene‐induced senescence marker p16 INK4A and the outer subventricular zone radial glia progenitor marker HOPX in CD34+ cells was confirmed by multiplex immunostaining. Pseudotime analysis showed that abnormal cells share a common lineage from progenitors to myelinating oligodendrocytes. Epilepsy surgery led to seizure freedom in eight of the 10 patients with BRAF mutant lesions. Interpretation BRAF V600E underlies a subset of MTLE‐HS and epileptogenic non‐expansive neocortical focal lesions. Detection of the oncogenic variant may help diagnosis and open perspectives for targeted therapies

Identification of Umbre Orthobunyavirus as a Novel Zoonotic Virus Responsible for Lethal Encephalitis in 2 French Patients With Hypogammaglobulinemia

International audienceBackground: Human encephalitis represents a medical challenge from a diagnostic and therapeutic point of view. We investigated the cause of 2 fatal cases of encephalitis of unknown origin in immunocompromised patients.Methods: Untargeted metatranscriptomics was applied on the brain tissue of 2 patients to search for pathogens (viruses, bacteria, fungi, or protozoans) without a prior hypothesis.Results: Umbre arbovirus, an orthobunyavirus never previously identified in humans, was found in 2 patients. In situ hybridization and reverse transcriptase-quantitative polymerase chain reaction (RT-qPCR) showed that Umbre virus infected neurons and replicated at high titers. The virus was not detected in cerebrospinal fluid by RT-qPCR. Viral sequences related to Koongol virus, another orthobunyavirus close to Umbre virus, were found in Culex pipiens mosquitoes captured in the south of France where the patients had spent some time before the onset of symptoms, demonstrating the presence of the same clade of arboviruses in Europe and their potential public health impact. A serological survey conducted in the same area did not identify individuals positive for Umbre virus. The absence of seropositivity in the population may not reflect the actual risk of disease transmission in immunocompromised individuals.Conclusions: Umbre arbovirus can cause encephalitis in immunocompromised humans and is present in Europe

Identification d’un nouvel arbovirus neurotrope en France : le virus Umbre

International audienceNotre laboratoire a mis en place une collaboration avec le laboratoire de neuropathologie de l’hôpital de la Pitié-Salpêtrière pour explorer une série post-mortem de cas d’encéphalites humaines d’étiologie inconnue par un séquençage NGS profond et non ciblé du transcriptome, à la recherche de séquences de pathogènes. Le virus Umbre, un virus du genre orthobunyavirus, a été identifié chez deux patients immunodéprimés décédés en 2013 et 2019. Le virus infecte des neurones du cortex cérébral, la moelle épinière et le foie. Le virus Umbre a été décrit initialement dans les années 1950 dans des populations de moustiques Culex en zone Asie Pacifique, mais n’avait auparavant ni été isolé chez des mammifères (dont l’homme), ni détecté en Europe. Cette infection par le virus Umbre chez deux patients français, dont l’un vivait dans la région Occitanie et n’avait jamais voyagé en dehors de France métropolitaine, et l’autre avait fait une croisière en méditerranée avant l’apparition des symptômes, nous a amené à rechercher l’origine de la contamination dans des moustiques. Une investigation réalisée en partenariat avec le CIRAD de Montpellier et l’EID Méditerranée a permis d’identifier des séquences du genre orthobunyavirus très proches du virus Umbre dans des moustiques Culex de Camargue. Une enquête sérologique par un test développé à l’Institut Pasteur sur une population du sud de la France composée d’environ 300 personnes « contrôles » et d’une vingtaine de cas « encéphalites » n’a pas mis en évidence de réponse anticorps contre le virus Umbre. Ce résultat suggère que la fréquence de l’infection dans la population générale est au plus faible, ce qui ne reflète donc pas le risque pour les personnes immunodéprimées. Cette découverte d’un nouvel arbovirus responsable d’encéphalite, et son existence en France, présente un intérêt particulier en matière de santé publique