Study of the first paramagnetic to ferromagnetic transition in as prepared samples of Mn-Fe-P-Si magnetocaloric compounds prepared by different synthesis routes

International audienceMagnetocaloric materials with composition of Mn 1.3 Fe 0.65 P 0.5 Si 0.5 have been prepared by ball milling and solid-state reaction methods and consolidated using powder annealing, and conventional and spark plasma sintering. Magnetic and calorimetric measurements show remarkable differences upon first cooling, and slight differences on second and further coolings between the samples prepared by different synthesis routes. Further measurements using Hall probe imaging in high magnetic field have been also carried out. As-prepared samples have been cooled down just above the critical temperature, and the first phase transition has been induced by application of a magnetic field. Bulk samples show staircase isothermal magnetization curves whereas powders show smoother transition curves

EXAFS unraveling of the Fe substitution sites in high anisotropic nanocrystalline Pr Co , Fe 3

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Magnetic properties and magnetocaloric effect in amorphous Co35Er65 ribbon

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Reconstruction of perfect ZnO nanowires facets with high optical quality

International audienceZnO nanowires were grown on sapphire substrates using metalorganic chemical vapor deposition. The samples were subsequently annealed under zinc pressure in a vacuum-sealed ampoule, at temperature ranging from 500 to 800°C. The originality and the main motivation to provide a zinc-rich atmosphere were to prevent the out-diffusion of zinc from the nanowires. In doing so, the perfect structural properties and the morphology of the nanowires are kept. Interestingly, photoluminescence experiments performed on nanowires annealed in a narrow window of temperature [580-620°C] show a spectacular improvement of the optical quality, as transitions commonly observable in high quality bulk samples are found. In addition, the intensity of the so-called "surface excitons" (SX) is strongly decreased. To accurately investigate the chemical modifications of the surface, XPS experiments were carried out and show that zinc hydroxide species and/or Zn(OH)2 sublayer were partially removed from the surface. These results suggest that the annealing process in zinc vapor helps to properly reconstruct the surface of ZnO nanowires, and improves the optical quality of their core. Such a thermal treatment at moderate temperature should be beneficial to nanodevices involving surface reaction, e.g. gas sensors

Comparative Study of Nanoparticles Fe 100−x Co x Alloy Synthesized by High Energy Ball Milling and by Polyol Process

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Un incidentalome surrenalien inhabituel: le ganglioneurome

Le ganglioneurome est une tumeur neurogène bénigne, rare, qui se développe à partir des cellules ganglionnaires sympathiques. Elle se localise essentiellement dans la région rétropéritonéale. La localisation surrénalienne est rare. Nous rapportons un cas de ganglioneurome surrénalien chez une femme âgée de 42 ans, asthmatique et atteinte de dilatation des bronches. La tumeur est découverte fortuitement sur un scanner thoraco-abdominal demandé dans le cadre du bilan étiologique de sa dilatation des bronches. Le diagnostic a été confirmé par l’examen anatomopathologique

Influence of particle size on the magnetocaloric properties of Mn1.30Fe0.65P0.5Si0.5 powders

International audienceWe present the results of an experimental investigation on the magnetocaloric properties of Mn1.30Fe0.65P0.5Si0.5 powders with different average particle sizes. Specific heat capacity under magnetic field cp(H,T) and magnetic field induced isothermal entropy change Δsiso(H,T) were measured by Peltier calorimetry. Thermal hysteresis is found to decreases with the particle size, but the refrigerant performance, evaluated by using the product Δsiso ΔTad of the isothermal entropy change Δsiso and the adiabatic temperature change ΔTad , has only slight dependence on the particle size

Round cell sarcoma of the colon with CIC rearrangement

Abstract Background The CIC-rearranged sarcoma is a very rare highly aggressive malignant soft tissue group of tumors. It has recently been described as highly aggressive soft tissue tumors of children and young adults sharing similar morphological features with the Ewing sarcoma. The digestive localization is exceptional. Case presentation A 14-year-old male presented with a history of abdominal pain for 1 year, which increased in intensity over the last 2 months. Imaging findings showed a large heterogeneous mesenteric mass on the left flank of the abdomen. Exploratory laparotomy was performed and revealed a large cystic hypervascularized mass depending on the transverse colon and mesocolon. A wide excision of the lesion was performed with segmental colectomy. No postoperative complications were noted. The microscopic examination revealed a vaguely nodular growth of undifferentiated small round cells, arranged in solid sheets separated by thin fibrous septa with a scarce stroma. After an uncomplicated post-operative course, the patient was referred for chemotherapy. The patient died 2 months later with a peritoneal and pleural progression. Conclusions The CIC-rearranged sarcoma is an aggressive tumor. There is no standard therapy for this rare disease. Their treatment includes surgery and chemotherapy. Resistance to chemotherapy is common. Further publications and studies will help to determine a standard therapy for this rare disease