44 research outputs found

    Immunoregulation in human malaria: the challenge of understanding asymptomatic infection

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    Method for removing a part made of a material having a glass-transition tempertaure from a mold, and molding machine

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    The invention relates to a method for removing a part from a mold and to a machine for molding said part, which is in particular made of a material having a glass-transition temperature and a melting temperature that is higher than the glass-transition temperature, and which is shaped in the cavity of a mold including at least two mold portions (3, 4) defining said shaping cavity (5) therebetween, wherein the mold is at a temperature between said glass-transition temperature and said melting temperature, and wherein the method comprises: opening the mold by spacing apart said mold portions (3, 4); locally spraying a cooling gas toward the part remaining in a portion of the mold using at least one nozzle (9); and, after a predetermined time period following the start of spraying the gas, ejecting the part from said portion of the mold, the time period being such that the part reaches a temperature that is lower than the glass-transition temperature thereof

    Thermoplastic Forming of Bulk Metallic Glasses

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    International audienceMetallic glasses display interesting mechanical properties including high mechanical resistance and large capacity to store elastic energy. Since metallic glasses can now be produced in bulk conditions, they can be used for structural applications. In this new context, thermoforming of metallic glasses can be a particularly well adapted technique for production of small size components with good surface finish. As for other glasses, metallic glasses can be preferentially thermoformed in their supercooled liquid region. However, since metallic glasses are still emerging materials, the mechanisms of high temperature deformation remain not completely understood and intensive work is currently carried out to identify the elementary mechanisms of deformation. Moreover, since thermoforming is performed in the supercooled liquid region, the thermal stability of the glass to be formed is a key point for the success of the thermoforming process. Finally, it is also shown that thermoforming conditions can be used to produce multi materials associating metallic glasses and conventional metallic alloys

    Assessment of the neutrophilic antibody-dependent respiratory burst (ADRB) response to Plasmodium falciparum

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    Assessment of different ADRB assays to determine their suitability for the evaluation of neutrophil stimulation by antimalarial antibodies. Semi-immunity against Pf malaria is based on a combination of cellular and humoral immune responses. PMNs and IgGs are considered important components of this process, but the underlying mechanisms are unclear. We investigated the neutrophilic ADRB by analyzing the production of ROS in response to Pf antigen-specific IgGs bound to solid-phase immobilized antigens (sADRB) or whole merozoites (mADRB). We found that the PMN stimulations in each assay were based on different underlying mechanisms, demonstrating the importance of the assay set-up for the evaluation of antibody-triggered PMN responses. In the sADRB assay, ROS were produced externally, and by specific blocking of CD32(a)/FcRII(a), the immediate neutrophilic response was abolished, whereas the removal of CD16(b)/FcRIII(b) had no substantial effect. The key role of CD32(a) was confirmed using CD16(b)-deficient PMNs, in which similar changes of neutrophilic ADRB profiles were recorded after treatment. In the mADRB assay, ROS were produced almost exclusively within the cell, suggesting that the underlying mechanism was phagocytosis. This was confirmed using an additional phagocytosis assay, in which PMNs specifically ingested merozoites opsonized with Ghanaian plasma IgGs, seven times more often than merozoites opsonized with European plasma IgGs (P<0.001). Our data show that assay set-ups used to evaluate the responses of PMNs and perhaps other effector cells must be chosen carefully to evaluate the appropriate cellular responses. Our robust, stable, and well-characterized methods could therefore be useful in malaria vaccine studies to analyze the antimalarial effector function of antibodies

    Déformation à chaud des verres métalliques massifs – thermoformage et élaboration de multimatériaux

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    Depuis que l’on sait élaborer des verres métalliques sous forme massive et plus uniquement sous forme de rubans, leurs propriétés mécaniques les rendent particulièrement intéressants pour la réalisation de pièces structurales. Dans ce contexte, la capacité à thermoformer ces verres devient un réel enjeu. En effet, le thermoformage est une technique bien adaptée à la réalisation, avec une bonne précision dimensionnelle, de pièces complexes de petites dimensions. Les conditions opératoires de mise en forme doivent être associées aux rhéologies optimales de déformation du verre mais également permettre de préserver la structure amorphe du matériau pendant le procédé. Enfin, ces techniques de formage à chaud peuvent également permettre l’élaboration de multimatériaux associant verres métalliques et alliages métalliques traditionnels

    Rekonstruktion des AC- Gelenkes bei Rockwood IV und V Verletzungen mittels Doppel- Tight Rope®: Funktionelles Outcome und Komplikationen bei 19 Patienten

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    Background: Monoclonal antibodies (mAbs) are essential tools in biological research, diagnosis and therapy, and are conventionally produced in murine hybridoma cell lines. Professional applications of mAbs depend on the steady supply of material. Because hybridoma cultures can stop producing the antibody or even die, preservation of the unique epitope specificity of mAbs by rescue of the sequences encoding the antibody variable domains (V regions) is important. The availability of these sequences enables not only the recombinant expression of the original antibody for further applications, but opens the road for antibody engineering towards innovative diagnostic or therapeutic applications. A time-and cost-efficient production system enabling the detailed analysis of the antibodies is an essential requirement in this context. Methods: Sequences were rescued from three hybridoma cell lines, subjected to sequence analysis, subcloned into binary expression vectors and recombinantly expressed as chimeric mAb (constant regions of human IgG1:k1) in Nicotiana benthamiana plants. The properties of the recombinant and the murine mAbs were compared using competition enzyme-linked immunosorbent assay (ELISA) and surface plasmon resonance (SPR) spectroscopy. The recognition of native PfMSP4 by the recombinant mAb was analysed by immunofluorescence staining of Pf 3D7A schizonts and by western blot analysis of merozoite extract. Results: The rescued sequences of all three hybridoma cell lines were identical. The recombinant mAb was successfully expressed as IgG in plants at moderate levels (45 mg/kg fresh leaf weight). Preservation of the original epitope was demonstrated in a competition ELISA, using recombinant mAb and the three murine mAbs. EGF PfMSP4-specific affinities were determined by SPR spectroscopy to 8 nM and 10 nM for the murine or recombinant mAb, respectively. Binding to parasite PfMSP4 was confirmed in an immunofluorescence assay showing a characteristic staining pattern and by western blot analysis using merozoite extract. Conclusions: As demonstrated by the example of an EGF PfMSP4-specific antibody, the described combination of a simple and efficient hybridoma antibody cloning approach with the flexible, robust and cost-efficient transient expression system suitable to rapidly produce mg-amounts of functional recombinant antibodies provides an attractive method for the generation of mAbs and their derivatives as research tool, novel therapeutics or diagnostics
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