272 research outputs found

    PHARAO Laser Source Flight Model: Design and Performances

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    In this paper, we describe the design and the main performances of the PHARAO laser source flight model. PHARAO is a laser cooled cesium clock specially designed for operation in space and the laser source is one of the main sub-systems. The flight model presented in this work is the first remote-controlled laser system designed for spaceborne cold atom manipulation. The main challenges arise from mechanical compatibility with space constraints, which impose a high level of compactness, a low electric power consumption, a wide range of operating temperature and a vacuum environment. We describe the main functions of the laser source and give an overview of the main technologies developed for this instrument. We present some results of the qualification process. The characteristics of the laser source flight model, and their impact on the clock performances, have been verified in operational conditions.Comment: Accepted for publication in Review of Scientific Instrument

    Crystal structure of Sar1-GDP at 1.7 Å resolution and the role of the NH2 terminus in ER export

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    The Sar1 GTPase is an essential component of COPII vesicle coats involved in export of cargo from the ER. We report the 1.7-Å structure of Sar1 and find that consistent with the sequence divergence of Sar1 from Arf family GTPases, Sar1 is structurally distinct. In particular, we show that the Sar1 NH2 terminus contains two regions: an NH2-terminal extension containing an evolutionary conserved hydrophobic motif that facilitates membrane recruitment and activation by the mammalian Sec12 guanine nucleotide exchange factor, and an α1' amphipathic helix that contributes to interaction with the Sec23/24 complex that is responsible for cargo selection during ER export. We propose that the hydrophobic Sar1 NH2-terminal activation/recruitment motif, in conjunction with the α1' helix, mediates the initial steps in COPII coat assembly for export from the ER

    A new isomer in 125^{125}La

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    Levels in 125^{125}La have been studied via ÎČ+\beta ^+/EC decay of on-line mass-separated 125^{125}Ce using the HIGISOL technique. A new (390 ±\pm 40) ms isomer is definitely attributed to 125^{125}La by conversion electron measurements of the 107 keV E3 isomeric transition

    Beta-decay properties of 25^{25}Si and 26^{26}P

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    The ÎČ\beta-decay properties of the neutron-deficient nuclei 25^{25}Si and 26^{26}P have been investigated at the GANIL/LISE3 facility by means of charged-particle and Îł\gamma-ray spectroscopy. The decay schemes obtained and the Gamow-Teller strength distributions are compared to shell-model calculations based on the USD interaction. B(GT) values derived from the absolute measurement of the ÎČ\beta-decay branching ratios give rise to a quenching factor of the Gamow-Teller strength of 0.6. A precise half-life of 43.7 (6) ms was determined for 26^{26}P, the ÎČ\beta- (2)p decay mode of which is described

    Restauration morpho-dynamique et redynamisation de la section court-circuitée du Rhin en aval du barrage de Kembs (projet INTERREG / EDF)

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    National audienceThe Upper Rhine River has been heavily impacted by channelization for flood protection and navigation, and then by damming for hydropower generation. In normal non flooding conditions, most of the flows are diverted in a canalized section whereas the regulated “old Rhine” bypassed reach runs a minimum flow. Between Huningue and Neuf-Brisach, engineering works induced simplification and stabilization of the channel pattern from a formerly braiding sector to a single incised channel, hydrological modifications, bottom armouring due to bedload decrease, and thus ecological alterations. Two complementary and interdisciplinary projects have been initiated to restore alluvial morphodynamics: i) the international “INTERREG IV - Redynamisation of the old Rhine” project (2009-2012) coordinated by the Alsace region, France; ii) the left bank “controlled erosion” project launched by ElectricitĂ© de France (EDF) within Kembs hydroelectric station relicensing process since 2003-2004. The purpose of these projects is to evaluate the feasibility of an important hydro-morphological and ecological restoration plan on a 45 km long reach, through both field testing of bank erosion techniques at favourable locations, and artificial sediments input from right bank excavations. This will help define possible long term prospective scenarios, in order to restore sustainable sediment transport, morphodynamics variability and associated ecological functions. The study will involve historical analysis, hydro-morphological / hydraulic physical and numerical modelling, physical and ecological monitoring, and sociological aspectsLe Rhin alsacien-allemand a enregistrĂ© de profondes modifications morphologiques et hydrologiques Ă  la suite de sa correction et de sa rĂ©gularisation pour la protection contre les crues et la navigation, puis aprĂšs la construction de barrages hydro-Ă©lectriques. Les amĂ©nagements rĂ©alisĂ©s entre Huningue et Neuf-Brisach ont engendrĂ© une simplification et une stabilisation du style fluvial. Un fleuve en tresses a cĂ©dĂ© la place Ă  un chenal unique incisĂ©. Le fond de chenal est devenu pavĂ© Ă  cause d’une diminution des apports de charge de fond et des altĂ©rations Ă©cologiques ont Ă©tĂ© observĂ©es (simplification des habitats aquatiques et riverains). Deux projets complĂ©mentaires et interdisciplinaires ont Ă©tĂ© engagĂ©s afin de restaurer une dynamique des formes alluviales : i) le projet international INTERREG IV – Redynamisation du Vieux Rhin (2009-2012) sous l’impulsion de la rĂ©gion Alsace ; ii) le projet d’érosion maitrisĂ©e des berges de la rive gauche conduit par ElectricitĂ© de France (EDF) dans le cadre du renouvellement de la concession de l’amĂ©nagement de Kembs. L’objectif des deux projets est de dĂ©finir un plan de restauration hydro-morphologique et Ă©cologique conduisant Ă  la redynamisation d’un tronçon de 45 km. L’étude repose sur une analyse historique, l’exploitation de modĂšles Ă  la fois physiques et numĂ©riques, et les suivis morphologiques in situ d’une recharge artificielle en sĂ©diments et d’érosions de berge contrĂŽlĂ©es. Ces Ă©tudes de faisabilitĂ© sont complĂ©tĂ©es par des analyses Ă©cologique et sociologique pour apprĂ©cier l’impact socio-environnemental de ces projets

    PPARÎł Controls Dectin-1 Expression Required for Host Antifungal Defense against Candida albicans

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    We recently showed that IL-13 or peroxisome proliferator activated receptor Îł (PPARÎł) ligands attenuate Candida albicans colonization of the gastrointestinal tract. Here, using a macrophage-specific Dectin-1 deficient mice model, we demonstrate that Dectin-1 is essential to control fungal gastrointestinal infection by PPARÎł ligands. We also show that the phagocytosis of yeast and the release of reactive oxygen intermediates in response to Candida albicans challenge are impaired in macrophages from Dectin-1 deficient mice treated with PPARÎł ligands or IL-13. Although the Mannose Receptor is not sufficient to trigger antifungal functions during the alternative activation of macrophages, our data establish the involvement of the Mannose Receptor in the initial recognition of non-opsonized Candida albicans by macrophages. We also demonstrate for the first time that the modulation of Dectin-1 expression by IL-13 involves the PPARÎł signaling pathway. These findings are consistent with a crucial role for PPARÎł in the alternative activation of macrophages by Th2 cytokines. Altogether these data suggest that PPARÎł ligands may be of therapeutic value in esophageal and gastrointestinal candidiasis in patients severely immunocompromised or with metabolic diseases in whom the prevalence of candidiasis is considerable

    Recurrent Scedosporium apiospermum mycetoma successfully treated by surgical excision and terbinafine treatment: a case report and review of the literature

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    Background: Scedosporium apiospermum is an emerging opportunistic filamentous fungus, which is notorious for its high levels of antifungal ‑resistance. It is able to cause localized cutaneous or subcutaneous infections in both immu‑ nocompromised and immunocompetent persons, pulmonary infections in patients with predisposing pulmonary diseases and invasive mycoses in immunocompromised patients. Subcutaneous infections caused by this fungus frequently show chronic mycetomatous manifestation. Case report: We report the case of a 70 ‑year ‑old immunocompromised man, who developed a fungal mycetoma‑ tous infection on his right leg. There was no history of trauma; the aetiological agent was identified by microscopic examination and ITS sequencing. This is the second reported case of S. apiospermum subcutaneous infections in Hungary, which was successfully treated by surgical excision and terbinafine treatment. After 7 months, the patient remained asymptomatic. Considering the antifungal susceptibility and increasing incidence of the fungus, Sce - dosporium related subcutaneous infections reported in the past quarter of century in European countries were also reviewed. Conclusions: Corticosteroid treatment represents a serious risk factor of S. apiospermum infections, especially if the patient get in touch with manure ‑enriched or polluted soil or water. Such infections have emerged several times in European countries in the past decades. The presented data suggest that besides the commonly applied voricona‑ zole, terbinafine may be an alternative for the therapy of mycetomatous Scedosporium infections
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