Morbidité post-opératoire précoce de l'anastomose pancréato-gastrique après duodénopancréatectomies céphaliques (étude rétrospective sur 10 ans à propos de 85 cas avec la même technique opératoire d'intussusception du moignon pancréatique au CHU de Poitiers)

POITIERS-BU Médecine pharmacie (861942103) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Experimental investigations on the process of forming functional microstructured blades from highly filled thermoplastic composites prepared with La(Fe, Si)13 alloys

International audienceHighly loaded polymer extrusion and forming processes are low-cost manufacturing processes which use con-tinuous polymer profiles to elaborate magnetocaloric composites and 2D structured thin components and shapethem into a wide variety of materials. The development of functional composites involves various requirements,specifications, and composite component designs. A composite must exhibit a high shear viscosity for polymerextrusion processing and permit extremely high loadings of solids to produce functional magnetocaloric prop-erties which are equivalent to those of bulk materials. A composite material based on highly loaded magneto-caloric composites was elaborated and investigated by using gas-atomised La(Fe,Si)13alloys. This appears to beuseful in the fabrication of functional structured magnetocaloric components as regenerators or blade shapes. Inthe present study, composite elaborations were investigated with specific focus on the homogeneity and rheo-logical behaviours for a powder size distribution between 13 and 143μm, solid loadings of 35%–65% by volume,and shear rates of 102–103/s. The binder used was based on different thermoplastic polymers with low meltingtemperatures, such as polypropylene or low-density polyethylene, to avoid dehydrogenation of the magneto-caloric powders during the material-forming process. The shaping of structured blades by highly loaded polymerprocessing from the compounding to the forming process through the development of innovative processes anddedicated extrusion lines equipped with well-designed microstructured thin-blade-forming tools was studied.Thin structured blades of thickness 0.5 mm were obtained with micropatterns of width 200μm, with the max-imal efficiency being 92%. The Curie temperature was determined from the powder stage to the mixing processand thefinal material shaping to validate the magnetocaloric properties and quantify the limits of the meth-odologies developed with different powders (the Curie temperature was adjusted to−21 and 23.5 °C). In thisregard, the elaborated composite and the structured thin extruded component were characterised in terms of thehomogeneity, magnetocaloric properties, and dimensional and geometric tolerances

Thermoplastic filled with magnetocaloric powder

International audienceMagnetic refrigeration is an innovative and promising alternative to traditional refrigeration systems. This technology does not require refrigeration gases and offers a high thermodynamic efficiency, reducing the global environmental impact associatedwith the process. However, the production ofmagnetocaloric components used as regenerators in magnetic refrigeration systems is a significant challenge. This work consists of developing an innovative process to obtainmagnetocaloric components by powder injection or extrusion moulding. A component containing up to 91.5 wt.% magnetocaloric powder was obtained using a gas atomised magnetocaloric powder La–Fe–Si alloy patented by Erasteel. The powder is first mixed with a thermoplastic polymer to obtain a “ready to shape” feedstock. Then, the feedstock is either injected or extruded to obtain the magnetocaloric component. Characterisations of the thermo-physical and mechanical properties are carried out during all stages of processing, from pure powder to injected parts. A study on the modification of the Curie temperature as aresult of dehydrogenation was performed during each processing stages. Good processability was demonstrated for the highly loaded feedstock and conservation of the magnetocaloric properties during the process. Finally, the process does not induce any mass loss and allows the production of stable pieces containing a giant magnetocaloric effect

Serpin B1 defect and increased apoptosis of neutrophils in Cohen syndrome neutropenia

International audienc