7 research outputs found
First principle energies of binary and ternary phases of the FeâNbâNiâCr 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 FeâNiâCrâNb 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 (ÎŒ) binary phases, and the X8Y4Z18-D8b (Ï) 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 FeâNbâNiâCr system
This is an author-deposited version published in: http://oatao.univ-toulouse.fr/ Eprints ID: 5546 To cite this version: ConnĂ©table, 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 (”) binary phases, and the X 8 Y 4 Z 18 -D8 b (Ï ) 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 nonâexpansive lesions in focal epilepsies
International audienceAbstract Objective Mesial Temporal Lobe Epilepsyâassociated Hippocampal Sclerosis (MTLEâHS) is a syndrome associated with various aetiologies. We previously identified CD34âpositive extravascular stellate cells (CD34+ cells) possibly related to BRAF V600E oncogenic variant in a subset of MTLEâHS. 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 MTLEâHS samples (25 with CD34+ cells) and nine nonâexpansive neocortical lesions resected during epilepsy surgery (five with CD34+ cells). Ex vivo multiâelectrode array recording, immunolabelling, methylation microarray and single nuclei RNAseq were performed on BRAF wildtype MTLEâHS and BRAF V600E mutant nonâexpansive lesion of hippocampus and/or neocortex. Results We identified a BRAF V600E oncogenic variant in five MTLEâHS 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 coâexpression of the oncogeneâinduced 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 MTLEâHS and epileptogenic nonâexpansive 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 dâun nouvel arbovirus neurotrope en France : le virus Umbre
International audienceNotre laboratoire a mis en place une collaboration avec le laboratoire de neuropathologie de lâhĂŽpital de la PitiĂ©-SalpĂȘtriĂšre pour explorer une sĂ©rie post-mortem de cas dâencĂ©phalites humaines dâĂ©tiologie inconnue par un sĂ©quençage NGS profond et non ciblĂ© du transcriptome, Ă la recherche de sĂ©quences de pathogĂšnes. Le virus Umbre, un virus du genre orthobunyavirus, a Ă©tĂ© identifiĂ© chez deux patients immunodĂ©primĂ©s dĂ©cĂ©dĂ©s en 2013 et 2019. Le virus infecte des neurones du cortex cĂ©rĂ©bral, la moelle Ă©piniĂšre et le foie. Le virus Umbre a Ă©tĂ© dĂ©crit initialement dans les annĂ©es 1950 dans des populations de moustiques Culex en zone Asie Pacifique, mais nâavait auparavant ni Ă©tĂ© isolĂ© chez des mammifĂšres (dont lâhomme), ni dĂ©tectĂ© en Europe. Cette infection par le virus Umbre chez deux patients français, dont lâun vivait dans la rĂ©gion Occitanie et nâavait jamais voyagĂ© en dehors de France mĂ©tropolitaine, et lâautre avait fait une croisiĂšre en mĂ©diterranĂ©e avant lâapparition des symptĂŽmes, nous a amenĂ© Ă rechercher lâorigine de la contamination dans des moustiques. Une investigation rĂ©alisĂ©e en partenariat avec le CIRAD de Montpellier et lâEID MĂ©diterranĂ©e a permis dâidentifier des sĂ©quences du genre orthobunyavirus trĂšs proches du virus Umbre dans des moustiques Culex de Camargue. Une enquĂȘte sĂ©rologique par un test dĂ©veloppĂ© Ă lâInstitut Pasteur sur une population du sud de la France composĂ©e dâenviron 300 personnes « contrĂŽles » et dâune vingtaine de cas « encĂ©phalites » nâa pas mis en Ă©vidence de rĂ©ponse anticorps contre le virus Umbre. Ce rĂ©sultat suggĂšre que la frĂ©quence de lâinfection dans la population gĂ©nĂ©rale est au plus faible, ce qui ne reflĂšte donc pas le risque pour les personnes immunodĂ©primĂ©es. Cette dĂ©couverte dâun nouvel arbovirus responsable dâencĂ©phalite, et son existence en France, prĂ©sente un intĂ©rĂȘt particulier en matiĂšre de santĂ© publique