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The therapeutic management of aortic stenosis has been drastically changed by the advent of percutaneous valve replacement (TAVI). Since the first implantation, the indications have progressively been extended from the inoperable patient to the patient at low surgical risk. The main objective of this review is to describe the currently recommended main indications of TAVI depending on an individualized assessment of each patient's risk, technical characteristics and anatomical valvular criteria.

International audience; GaAsO4 is the highest performance piezoelectric material of the MIIIXVO4 alpha-quartz type group. First principles based calculations of the pure FeAsO4 show that the piezoelectric properties are strongly improved by replacing Ga3+ by a chemical element of the d-bloc like Fe3+. For GaAsO4, our calculations give, d11 = 7.08 and d14 = 5.76 pC/N, while these values are significantly higher in FeAsO4 to reach d11 = 18.77 and d14 = 13.78 pC/N; about a factor of three greater than in GaAsO4 due to the increase of the elastic compliances of FeAsO4 with respect to GaAsO4. These results show that the electronic configuration and particularly the involvement of the d-orbitals in the M-O bonds in the MIIIO4 tetrahedron could be at the origin of this increasing. By considering a linear dependence of d11 or d14 between the parent compounds, GaAsO4 and FeAsO4, we get the following equations for the Ga(1-x)FexAsO4 solid solution: d11 [pC/N] = 11.689 xFe + 7.082 and d14 [pC/N] = 8.021 xFe + 5.762. These predictions motivated the first synthesis of mixed Ga(1-x)FexAsO4 solid solutions with x = 0,09; 0,18 and 0,45. The hydrated compounds, Ga1-xFexAsO4,2H2O, were obtained by hydrothermal synthesis and the alpha-quartz phases Ga1-xFexAsO4 were crystallized with a thermal treatment in an oven at 600 °C for 24h. XRD patterns show that the cell parameters are in accordance with a Vegard's law for the orthorhombic hydrated phases (Pbca space group) and for the trigonal dehydrated alpha-quartz phases (P3121 space group). Raman spectroscopy data obtained for the hydrated phases confirm the results of the literature on FeAsO4·2H2O, GaAsO4·2H2O and other arsenate analogues as well as their substituted analogues on the M and X sites. For the dehydrated alpha-quartz phases, all the main peaks observed in Raman spectra have been observed and the assigned by analyzing the experimental spectra measured in solid solutions and the calculated spectra in the parent end-member compounds. DFT calculations were used to identify the Raman vibrational modes. As in the case of GaAsO4, no libration mode of oxygen atoms is present for FeAsO4 that could lead to a very high thermal stability. These results prove the interest of α-quartz type FexGa1-xAsO4 solid solutions.

The adherence and properties of p-type PbSe layer grown on CaF2//Si(1 1 1) by molecular beam epitaxy (MBE) can be improved using an additional stage, corresponding to a CaF2 layer annealing under selenium flux. Reflective high-energy electron diffraction (RHEED) and Auger electron spectroscopy (AES) measurements demonstrate that this step leads to the formation of CaSe nuclei. The best crystalline quality of PbSe layers is reached with high PbSe growth rates corresponding to a thick PbSe coalescence layer. In contrast, electrical properties are not easily controllable by the Se/PbSe flux ratio adjustment.

The presence of contamination at the Pb/p-PbSe interface corresponding to a Schottky contact leads to the formation of an n-type inversion layer resulting in an ohmic behaviour. In this work, the PbSe oxidation kinetics by air exposure is studied using XPS and AES measurements. We found that an oxide layer is formed at the surface, containing PbO and SeO2 compounds. Secondly, the oxide layer dissolution in KOH-based solutions is investigated. A C- and O-decontaminated PbSe surface is obtained after a few minutes soaking in a bath containing ethylene glycol as solvent. Auger microanalysis demonstrates that the decontaminated surface is made of PbxSe with x

In this paper, the molecular beam epitaxy (MBE) technique is applied to IV–VI semiconducting materials such as PbSe. It is of interest to realize heterostructures with infrared (IR) detection properties on a Si wafer in order to obtain a compact optoelectronic device. Because of the lattice mismatch between PbSe and Si, a layer of CaF 2 is used as a buffer layer with intermediary physico-chemical parameters. The study presented in this paper is divided into two ways: optimization of the first interface CaF 2 /Si and the second interface. The annealing under vacuum of calcium fluoride film prepared by MBE is characterized by Auger electron spectroscopy, RHEED and atomic force microscopy. This treatment shows at low temperature (200°C) a weak oxidization, for temperatures above 600°C a surface rearrangement due to diffusion of CaF 2 molecules and for temperatures above 900°C CaF 2 molecular desorption. With optimization of the second interface PbSe/CaF 2 annealing of the CaF 2 surface under selenium flux enables CaF 2 surface stabilization over the 200–500°C temperature range. This treatment avoids surface oxidization and leads to a significant Se incorporation from 400°C necessary for good growth of the PbSe layer.

The growth of PbSe layer on Si(111) substrate via a CaF 2 thin buffer layer was realized by Molecular Beam Epitaxy (MBE). The process for forming native sulfide films by chemical and anodic sulfidization is described. These methods, frequently used for III–V and II–VI materials, have not been yet studied for the PbSe surface passivation. The structural characterizations were realized by X-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES) and atomic force microscopy (AFM). A comparative study between MBE, air exposure and passivated surfaces is developed. An AES semi-quantitative calculation allows to estimate the sulfur penetration thickness of about 15 A. The good chemical passivation and the stability in the time is shown.

Heterostructures of IV–VI compounds, such as epitaxial films of PbSe grown on Si(111) via a CaF 2 layer, have been the object of increasing scientific interest in the last few years because of their detection properties. A monolithic integration of the I-R detection functions is possible on an Si conventional read-out electronics. The high mismatch and the difference of the thermal expansion coefficients between Si and PbSe require the use of a buffer layer of CaF 2 . The CaF 2 /Si(111) interface has been widely studied but PbSe/CaF 2 belongs to a group of interfaces which has been rarely studied. Annealing of the CaF 2 surface under Se flux in the range 200–600°C shows the incorporation of Se into the CaF 2 surface at a temperature higher than the growth temperature. The Se incorporation increases the stability of the CaF 2 surface, avoids its oxidation and creates nucleation sites for PbSe. The optimization of the subsequent buffer layer is a key problem in the growth process. On a Se-terminated CaF 2 surface, the first stage of the PbSe nucleation has been studied by AES, RHEED, XPS and AFM.

Resume L'infection systemique a Malassezia furfur (Mf) n'est habituellement observee que chez les nouveau-nes et chez les malades immunodeprimes. Observation. - Un garcon de 2 ans 8 mois a ete par chimiotherapie pour un lymphome lymphoblastique T mediastinal avec envahissement leucemique. Une rechute meningee a ete observee 10 mois plus tard, necessitant une polychimiotherapie et une irradiation du systeme nerveux central. Une autogreffe de moelle osseuse a ete realisee 4 mois plus tard; un episode febrile a ete observe 3 jours apres, en phase d'aplasie, necessitant l'administration de ceftazidime, d'amikacine, de vancomycine et d'aciclovir. Ce traitement a ensuite ete modifie et complete par amphotericine B, cefotaxime et erythromycine. Les hemocultures ont ete negatives mais les frottis sanguins ont mis en evidence des levures dans les polynucleaires apres cytocentrifugation; ces levures correspondaient a du Mf qui etait egalement present au niveau du catheter central retire apres quelques jours de traitement par amphotericine B, flucytosine et fluconazole. L'enfant a alors ete traite par du GM-CSF par voie souscutanee (5 μg/kg/j). Ce traitement a amene la disparition progressive de l'aplasie et la guerison de l'infection a Mf. Conclusion. - Cette observation represente un nouveau cas d'infection systemique a Mf observee chez un enfant immunodeprime, recevant par ailleurs une nutrition parenterale lipidique.

A new outbreak of trichinosis occured in 1991 in Auvergne. The clinical investigation disclosed 23 cases related to horsemeat consumption.

Clinical and epidemiological features on Fasciola hepatica distomatosis in the Cantal: 33 cases over 11 years.

A new natural site of fievre boutonneuse was disclosed in 1992 in the northern part of Auvergne: the authors emphasize the relationship between epidemiological and clinical statement in the investigation.

78 consecutive cases of PCP have been analysed: 59 (75,6%) cases were associated with HIV infection and 19 (24,4%) cases were associated with solid tumors and hematologic malignancies at advanced stage of the disease and renal transplantation. It could suggest primary prevention for such patients.

Thoracic wall involvement in chronic necrotizing pulmonary aspergillosis is rare. cANCA discovery has not been previously reported. Itraconazole represents an amphotericin B alternative therapy.

Resume Deux cas autochtones de leischmaniose humaine ont ete signales en Auvergne. Le nombre croissant de chiens leishmaniens en transit, comme la pullulation des phlebotomes au cours de l'ete, dans certaines localites de Limagne sont en faveur d'une transmission locale.