UV, stress and aging

Skin is a model of choice in studies on aging. Indeed, skin aging can be modulated by internal and external factors, reflecting its complexity. Two types of skin aging have been identified: intrinsic, mainly genetically determined and extrinsic—also called "photo-aging"—resulting on the impact of environmental stress and more precisely of UV rays. Simplified in vitro models, based on cellular senescence, have been developed to study the relationship between UV and aging. These models vary on the cell type (fibroblasts or keratinocytes, normal or immortalized) and the type of UV used (UVA or UVB)

Mycobacterium tuberculosis Exploits Asparagine to Assimilate Nitrogen and Resist Acid Stress during Infection

Mycobacterium tuberculosis is an intracellular pathogen. Within macrophages, M. tuberculosis thrives in a specialized membrane-bound vacuole, the phagosome, whose pH is slightly acidic, and where access to nutrients is limited. Understanding how the bacillus extracts and incorporates nutrients from its host may help develop novel strategies to combat tuberculosis. Here we show that M. tuberculosis employs the asparagine transporter AnsP2 and the secreted asparaginase AnsA to assimilate nitrogen and resist acid stress through asparagine hydrolysis and ammonia release. While the role of AnsP2 is partially spared by yet to be identified transporter(s), that of AnsA is crucial in both phagosome acidification arrest and intracellular replication, as an M. tuberculosis mutant lacking this asparaginase is ultimately attenuated in macrophages and in mice. Our study provides yet another example of the intimate link between physiology and virulence in the tubercle bacillus, and identifies a novel pathway to be targeted for therapeutic purposes. © 2014 Gouzy et al

Exome sequencing identifies germline variants in DIS3 in familial multiple myeloma

[Excerpt] Multiple myeloma (MM) is the third most common hematological malignancy, after Non-Hodgkin Lymphoma and Leukemia. MM is generally preceded by Monoclonal Gammopathy of Undetermined Significance (MGUS) [1], and epidemiological studies have identified older age, male gender, family history, and MGUS as risk factors for developing MM [2]. The somatic mutational landscape of sporadic MM has been increasingly investigated, aiming to identify recurrent genetic events involved in myelomagenesis. Whole exome and whole genome sequencing studies have shown that MM is a genetically heterogeneous disease that evolves through accumulation of both clonal and subclonal driver mutations [3] and identified recurrently somatically mutated genes, including KRAS, NRAS, FAM46C, TP53, DIS3, BRAF, TRAF3, CYLD, RB1 and PRDM1 [3,4,5]. Despite the fact that family-based studies have provided data consistent with an inherited genetic susceptibility to MM compatible with Mendelian transmission [6], the molecular basis of inherited MM predisposition is only partly understood. Genome-Wide Association (GWAS) studies have identified and validated 23 loci significantly associated with an increased risk of developing MM that explain ~16% of heritability [7] and only a subset of familial cases are thought to have a polygenic background [8]. Recent studies have identified rare germline variants predisposing to MM in KDM1A [9], ARID1A and USP45 [10], and the implementation of next-generation sequencing technology will allow the characterization of more such rare variants. [...]French National Cancer Institute (INCA) and the Fondation Française pour la Recherche contre le Myélome et les Gammapathies (FFMRG), the Intergroupe Francophone du Myélome (IFM), NCI R01 NCI CA167824 and a generous donation from Matthew Bell. This work was supported in part through the computational resources and staff expertise provided by Scientific Computing at the Icahn School of Medicine at Mount Sinai. Research reported in this paper was supported by the Office of Research Infrastructure of the National Institutes of Health under award number S10OD018522. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. The authors thank the Association des Malades du Myélome Multiple (AF3M) for their continued support and participation. Where authors are identified as personnel of the International Agency for Research on Cancer / World Health Organization, the authors alone are responsible for the views expressed in this article and they do not necessarily represent the decisions, policy or views of the International Agency for Research on Cancer / World Health Organizatio

CARACTERISATION D'UN CAPTEUR INERTIEL A ATOMES FROIDS

M Jean-Michel CARON Examinateur M Christian CHARDONNET Rapporteur M Noël DIMARCQ Directeur de thèse M Robin KAISER Rapporteur M Arnaud LANDRAGIN Co-directeur de thèse M Christoph WESTBROOK PrésidentSince recent developments in atom cooling techniques, matter wave applications are numerous. We present the first realization of a rate-gyroscope based on matter-waves associated to cold atoms, in order to reach a high sensitivity and stability. The setup, based on the Sagnac effect, is an atom interferometer where beam splitters and mirrors are realized with lasers pulses inducing stimulated Raman transitions. At the interferometer output, the phase shift between the two arms depends both on accelerations and rotations. We then use two counterpropagating atomic sources in order to discriminate between rotation and acceleration. We tested a new geometry for the laser beams, based on the lasers retroreflection, in order to reduce spurious phase shifts due to wavefront distorsions. The characterization of the first interferometric signal obtained with this setup is presented in this document. Thanks to the implementation of a vibration isolation system, sensitivities obtained after one second are 2,2.10-6 rad.s-1 for rotation et 6,2.10-6 m.s-2 for acceleration. This first characterization revealed the main limitation of the setup, which is presently the number of useful atoms. Further modifications on the experiment will improve this point. A new interferometer was tested, which presents a sensitivity to the rotation axis parallel to the atomic mean direction. This geometry opens possibilities for a new type of rate-gyroscopes, with very high sensitivity and stability.Depuis les développements des techniques de refroidissement d'atomes, les applications des ondes de matière ont fleuri. On présente la première réalisation d'un gyromètre fonctionnant sur des ondes associées à des atomes froids, dans le but d'atteindre une sensibilité et une stabilité inégalées. L'appareil, basé sur l'effet Sagnac, est un interféromètre atomique dont les séparatrices et miroirs sont réalisés à l'aide d'impulsions lasers induisant des transitions Raman stimulées aux nuages d'atomes froids de césium. En sortie de l'interféromètre, le déphasage dépend de la vitesse de rotation et de l'accélération de l'appareil. On utilise alors deux sources atomiques contrapropageantes afin de discriminer l'accélération de la rotation. Une géométrie novatrice permet de réduire les déphasages parasites dus aux aberrations des optiques, en rétroréfléchissant les faisceaux lasers réalisant les séparatrices. L'obtention d'un premier signal et sa caractérisation sont présentées dans cette thèse. Grâce à la mise en place d'un système d'isolation des vibrations, les sensibilités obtenues sur une seconde sont de 2,2.10-6 rad.s-1 pour la rotation et 6,2.10-6 m.s-2 pour l'accélération. Cette première caractérisation a mis en évidence la principale limite actuelle de l'appareil, qui est le nombre d'atomes utiles. Diverses modifications sur l'expérience permettront d'améliorer ce point. Par ailleurs, un nouvel interféromètre a été testé, fournissant une mesure de l'axe de rotation horizontal perpendiculaire aux faisceaux lasers, habituellement inaccessible. Cette géométrie ouvre la voie à de nouveaux types de gyromètres, de très hautes sensibilité et stabilité

Mères-célibataires : De la malédiction au libre-choix ? Regards croisés France/Grande-Bretagne

Collection Des idées et des femmes.Préface de Marie-Claire Pasquier.International audienc

Genre(s) et transparence

Collection Des idées et des femmes.Préface de Françoise Barret-Ducrocq.International audienc

FEMMES, SEXE, GENRE DANS L'AIRE ANGLOPHONE: Invisibilisation, stigmatisation et combats

International audienc

Nommer les femmes, le sexe et le genre

Collection Des idées et des femmes.Préface de Liliane Louvel.International audienc

Procédé et appareil de mesure de vitesse de rotation par interferometrie atomique

L'invention concerne la mesure de grandeurs inertielles par interférométrie atomique avec, en présence d'un champ d'accélération continue (Γ), l'émission de bouffées d'atomes lents depuis une source (1) unique selon la direction de l'accélération continue et à contresens de celle-ci, la manipulation cohérente des atomes en 4 + 2 mn (m = 2 ou 3, n ≥ 0) emplacements de leur trajectoire (tr) avec une séparatrice (π/2) pour séparer les atomes sur deux trajets (tr1, tr2) divergents, au moins une séparatrice (π) pour provoquer un effet miroir rendant les deux trajets (tr1', tr2') convergents, puis divergents, au moins une séparatrice (π) pour provoquer un second effet miroir pour rendre les deux trajets (tr1", tr2") convergents, et une séparatrice (π/2) pour faire interférer les deux paquets d'ondes atomiques, la variation détectée des atomes étant représentative d'une rotation d'axe Ox