255 research outputs found

    A linear programming approach to general dataflow process network verification and dimensioning

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    In this paper, we present linear programming-based sufficient conditions, some of them polynomial-time, to establish the liveness and memory boundedness of general dataflow process networks. Furthermore, this approach can be used to obtain safe upper bounds on the size of the channel buffers of such a network.Comment: In Proceedings ICE 2010, arXiv:1010.530

    Etude des phénomènes thermiques associés à la fabrication directe de pièces en TA6V par projection laser

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    International audienceDirect metal deposition is an additive manufacturing process that enables to build up a component layer-by-layer by the laser melting of a metal powder on a solid substrate, using a coaxial nozzle and a powder delivery head. The heating and cooling that occur in direct laser metal deposition can generate particular thermal conditions which are responsible of the specific microstructure and grain growth and lead to specific build features in term of mechanical properties. In the present work, an experimental study concerning laser-powder interaction, process instrumentation and metallurgical properties of the built parts is exposed. Then, a thermal balance has been established from thermal data of Ti-6Al-4V

    Chicken BAFF

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    Members of the tumor necrosis factor (TNF) family play key roles in the regulation of inflammation, immune responses and tissue homeostasis. Here we describe the identification of the chicken homologue of mammalian B cell activating factor of the TNF family (BAFF/BLyS). By searching a chicken EST database we identified two overlapping cDNA clones that code for the entire open reading frame of chicken BAFF (chBAFF), which contains a predicted transmembrane domain and a putative furin protease cleavage site like its mammalian counterparts. The amino acid identity between soluble chicken and human BAFF is 76%, considerably higher than for most other known cytokines. The chBAFF gene is most strongly expressed in the bursa of Fabricius. Soluble recombinant chBAFF produced by human 293T cells interacted with the mammalian cell-surface receptors TACI, BCMA and BAFF-R. It bound to chicken B cells, but not to other lymphocytes, and it promoted the survival of splenic chicken B cells in culture. Furthermore, bacterially expressed chBAFF induced the selective expansion of B cells in the spleen and cecal tonsils when administered to young chicks. Our results suggest that like its mammalian counterpart, chBAFF plays an important role in survival and/or proliferation of chicken B cells

    Chicken BAFF—a highly conserved cytokine that mediates B cell survival

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    Members of the tumor necrosis factor (TNF) family play key roles in the regulation of inflammation, immune responses and tissue homeostasis. Here we describe the identification of the chicken homologue of mammalian B cell activating factor of the TNF family (BAFF/BLyS). By searching a chicken EST database we identified two overlapping cDNA clones that code for the entire open reading frame of chicken BAFF (chBAFF), which contains a predicted transmembrane domain and a putative furin protease cleavage site like its mammalian counterparts. The amino acid identity between soluble chicken and human BAFF is 76%, considerably higher than for most other known cytokines. The chBAFF gene is most strongly expressed in the bursa of Fabricius. Soluble recombinant chBAFF produced by human 293T cells interacted with the mammalian cell‐surface receptors TACI, BCMA and BAFF‐R. It bound to chicken B cells, but not to other lymphocytes, and it promoted the survival of splenic chicken B cells in culture. Furthermore, bacterially expressed chBAFF induced the selective expansion of B cells in the spleen and cecal tonsils when administered to young chicks. Our results suggest that like its mammalian counterpart, chBAFF plays an important role in survival and/or proliferation of chicken B cell

    Morphologie et propriétés rhéologiques de mélanges ternaires PE/PA/argile : influence du mode d'élaboration et de la fraction d'argile.

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    L'amélioration des propriétés des mélanges de polymères immiscibles par l'ajout d'argile fait l'objet d'un intérêt croissant. Les systèmes ternaires étudiés sont constitués de polyéthylène, de polyamide et d'une nanocharge argileuse présentant une bonne affinité avec le polyamide. Deux modes d'élaboration sont confrontés : mélange d'un nanocomposite PA/argile et du polyéthylène d'une part, et mélange simultanément des trois composants d'autre part. L'influence du taux d'argile sur les propriétés morphologiques et rhéologiques de chaque système est étudiée. La morphologie des systèmes ternaires est très dépendante du mode d'élaboration et de la fraction de la phase dispersée. Les propriétés viscoélastiques sont étudiées en relation avec les propriétés morphologiques. Le comportement viscoélastique a été confronté aux prédictions du modèle de Palierne. Les différences dues au mode d'élaboration sont attribuées à la localisation préférentielle de l'argile dans la phase polyamide et/ou à l'interface PE/PA

    Conception robuste de systèmes dynamiques frottants

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    Le niveau des cycles limites obtenus dans les zones d'instabilité des systèmes frottants dépend fortement de la valeur du coefficient de frottement qui admet des dispersions importantes. Ainsi, l'objectif des travaux est d'étudier le comportement dynamique d'un système frottant afin de pouvoir déterminer la dispersion de l'amplitude des cycles limites lors des instabilités de type sprag-slip en prenant en compte les incertitudes du coefficient de frottement avec une approche par intervalles

    Maturation of Marginal Zone and Follicular B Cells Requires B Cell Activating Factor of the Tumor Necrosis Factor Family and Is Independent of B Cell Maturation Antigen

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    B cells undergo a complex series of maturation and selection steps in the bone marrow and spleen during differentiation into mature immune effector cells. The tumor necrosis factor (TNF) family member B cell activating factor of the TNF family (BAFF) (BLyS/TALL-1) plays an important role in B cell homeostasis. BAFF and its close homologue a proliferation-inducing ligand (APRIL) have both been shown to interact with at least two receptors, B cell maturation antigen (BCMA) and transmembrane activator and cyclophilin ligand interactor (TACI), however their relative contribution in transducing BAFF signals in vivo remains unclear. To functionally inactivate both BAFF and APRIL, mice transgenic for a soluble form of TACI were generated. They display a developmental block of B cell maturation in the periphery, leading to a severe depletion of marginal zone and follicular B2 B cells, but not of peritoneal B1 B cells. In contrast, mice transgenic for a soluble form of BCMA, which binds APRIL, have no detectable B cell phenotype. This demonstrates a crucial role for BAFF in B cell maturation and strongly suggests that it signals via a BCMA-independent pathway and in an APRIL-dispensable way

    Unveiling the Impact of Morphine on Tamoxifen Metabolism in Mice in vivo

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    Background- Tamoxifen is used to treat breast cancer and cancer recurrences. After administration, tamoxifen is converted into two more potent antitumor compounds, 4OH-tamoxifen and endoxifen by the CYP3A4/5 and 2D6 enzymes in human. These active compounds are inactivated by the same UDP-glucuronosyltransferases isoforms as those involved in the metabolism of morphine. Importantly, cancer-associated pain can be treated with morphine, and the common metabolic pathway of morphine and tamoxifen suggests potential clinically relevant interactions. Methods- Mouse liver microsomes were used to determine the impact of morphine on 4OH-tamoxifen metabolism in vitro. For in vivo experiments, female mice were first injected with tamoxifen alone and then with tamoxifen and morphine. Blood was collected, and LC-MS/MS was used to quantify tamoxifen, 4OH-tamoxifen, N-desmethyltamoxifen, endoxifen, 4OH-tamoxifen-glucuronide and endoxifen-glucuronide. Results- In vitro, we found increased Km values for the production of 4OH-tamoxifen-glucuronide in the presence of morphine, suggesting an inhibitory effect on 4OH-tamoxifen glucuronidation. Conversely, in vivo morphine treatment decreased 4OH-tamoxifen levels in the blood while dramatically increasing the formation of inactive metabolites 4OH-tamoxifen-glucuronide and endoxifen-glucuronide. Conclusions- Our findings emphasize the need for caution when extrapolating results from in vitro metabolic assays to in vivo drug metabolism interactions. Importantly, morphine strongly impacts tamoxifen metabolism in mice. It suggests that tamoxifen efficiency could be reduced when both drugs are co-administered in a clinical setting, e.g. to relieve pain in breast cancer patients. Further studies are needed to assess the potential for tamoxifen-morphine metabolic interactions in humans
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