48 research outputs found

    Accurate calculation of Euclidean Norms using Double-word arithmetic

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    International audienceWe consider the computation of the Euclidean (or L2) norm of an n-dimensional vector in floating-point arithmetic. We review the classical solutions used to avoid spurious overflow or underflow and/or to obtain very accurate results. We modify a recently published algorithm (that uses double-word arithmetic) to allow for a very accurate solution, free of spurious overflows and underflows. To that purpose, we use a double-word square-root algorithm of which we provide a tight error analysis. The returned L2 norm will be within very slightly more than 0.5 ulp from the exact result, which means that we will almost always provide correct rounding

    Accurate calculation of Euclidean Norms using Double-word arithmetic

    No full text
    We consider the computation of the Euclidean (a.k.a. L2) norm of an ndimensional vector in floating-point arithmetic. We review the classical solutions used to avoid spurious overflow or underflow and/or to obtain very accurate results. We modify a recently published algorithm to allow for a very accurate solution, free of spurious overflows and underflows. The returned result will be within very slightly more than 0.5 ulp from the exact result, which means that we will almost always provide correct rounding

    Sorption properties of activated carbons for the capture of methyl iodide in the context of nuclear industry

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    International audienceIn the present study, some commercially available activated carbons were evaluated towards the methyl iodide (CH3I) capture in the context of nuclear industry. A specific methodology was implemented in order to establish structure-activity relationships between adsorbent characteristics and its adsorption behavior towards CH3I. On the one hand, the investigated adsorbents were characterized by a combination of physico-chemical techniques. On the other hand, CH3I retention performance from batch sorption tests under different conditions (temperature and relative humidity) was studied using an original experimental setup. In this work, two conditions were investigated: (i) T = 35°C, R.H. = 26 % ([H2O] ∌15,000 ppmv); (ii) T = 75°C, R.H. = 30 % ([H2O] ∌130,000 ppmv). Different trends were obtained depending on the investigated scenario. At ambient conditions (i), CH3I adsorption performance was affected after KI/TEDA impregnation because of partial pore blockage phenomena induced by the of impregnants presence within the microporosity. However, TEDA impregnation was found to be required to enhance the trapping stability and to capture CH3I with superior efficiency at higher temperature (ii)

    The Intracellular Ion flux mediated by TMEM176A and TMEM176B is involved in the regulation of Dendritic Cell Functions

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    International audienceThe regulation of immune cells by intracellular ion channels remains poorly explored. Here we investigated the role of two cation channels encoded by Tmem176a and Tmem176b that are highly expressed in myeloid cells in the immune system. To avoid any functional compensation, we generated double knock-out (DKO) mice, allowing simultaneous deletion of these two highly redundant and coregulated genes using the CRISPR-Cas9 system. The absence of Tmem176a/b significantly impacted antigen processing and presentation to CD4+ T cells in vivo and selectively altered cytokine production by dendritic cells (DCs). Using a novel real-time fluorescence-based system to analyze intracellular trafficking we found that both channels co-localized in highly dynamic post-Golgi vesicles preferentially interacting with, but not accumulating in, acidic organelles. Thus, these results highlight the importance of TMEM176A/B-mediated cation flux for the fine regulation of DC biology

    The Intracellular Ion flux mediated by TMEM176A and TMEM176B is involved in the regulation of Dendritic Cell Functions

    No full text
    International audienceThe regulation of immune cells by intracellular ion channels remains poorly explored. Here we investigated the role of two cation channels encoded by Tmem176a and Tmem176b that are highly expressed in myeloid cells in the immune system. To avoid any functional compensation, we generated double knock-out (DKO) mice, allowing simultaneous deletion of these two highly redundant and coregulated genes using the CRISPR-Cas9 system. The absence of Tmem176a/b significantly impacted antigen processing and presentation to CD4+ T cells in vivo and selectively altered cytokine production by dendritic cells (DCs). Using a novel real-time fluorescence-based system to analyze intracellular trafficking we found that both channels co-localized in highly dynamic post-Golgi vesicles preferentially interacting with, but not accumulating in, acidic organelles. Thus, these results highlight the importance of TMEM176A/B-mediated cation flux for the fine regulation of DC biology
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