Étayer les relations parents–enfants en groupe de jeux quand l’enfant souffre d’autisme ou de troubles envahissants du développement

International audienceLe groupe de jeux "Peter Pan", pour enfants autistes ou souffrant de troubles envahissants du développement et leurs parents s'inscrit au sein de l'Hôpital de Jour du Centre Psychothérapique pour Enfants et Adolescents de Mulhouse (France), rattaché au secteur de psychiatrie infanto-juvénile 68I02 de l'hôpital de Rouffach. Le projet, adaptation à notre public du concept Calimusette et Pirouli (lieu d'accueil parents-enfants autour du jeu corporel et sensoriel), vise à étayer la relation parent-enfant, en restaurant plaisir partagé et estime de soi dans ces interactions parent-enfant meurtries. Le Modèle d'Observation Structurée des Interactions Parents-Enfants (MOSIPE), d'inspiration systémique, est l'un de nos outils. Le groupe est devenu groupe d'entraide. Etayé ainsi, chaque parent a été rétabli dans sa fonction parentale, et confirmé dans son expertise

Effect of the hydrogen dilution on the local microstructure in hydrogenated amorphous silicon films deposited by radiofrequency magnetron sputtering

The nature of the hydrogen bonding and content and their influence on the film microstructure have been investigated in detail, as a function of the H2 dilution and the residual pressure, in hydrogenated amorphous silicon (a-Si:H) films prepared by radiofrequency (rf) magnetron sputtering at a common substrate temperature (~ 250 °C) and pressure (5 × 10−4 torr) and high rates (11−15 Å/s). H2 percentages in the gas phase mixture (Ar + % H2) of 5, 10, 15 and 20% have been introduced during growth. For the 20% of H2, two different pressures of 5 × 10−4 and 50 × 10−4 torr were used. A combination of infrared absorption, optical transmission and elastic recoil detection analysis experiments have been carried out to fully characterize the samples in their as-deposited state. The results clearly indicate that for H2 percentage equal to or lower than 15% , the total bonded H content in the films increases as the H2 percentage increases, and then reaches a saturation value or even decreases for higher H2 percentage. Moreover, the microstructure is also found to be deeply affected by the H2 dilution and pressure. In particular, for high H2 percentage (20%) and high pressure (50 × 10−4 torr), unbounded H as well as polyhydride (Si-H2)n chains, possibly located in structural inhomogeneities such as voids, are also present in the films in addition to the isolated monohydride Si-H and polyhydride Si-H2 complexes. As a result, a reduction of the compactness of the film structure associated with a decrease of the refractive index n is observed. The optical gap is found to be rather controlled by the total bonded hydrogen content. The lowest proportion of isolated polyhydride Si-H2 complexes and the highest density are observed for films deposited with 10% of H2 in the gas phase and a pressure of 5 × 10−4 torr

Influence of the deposition conditions on the optoelectronic properties of R.F. magnetron sputtered a-Si:H films

We have studied the effect of the deposition conditions on the hydrogen incorporation modes and content and their effects on the optoelectronic properties of three different series of a-Si:H films prepared by R.F. magnetron sputtering at high substrate temperature (250 °C) and high deposition rates (~ 10 Å/s). We have correlated infrared absorption measurements with optical transmission and Photothermal Deflection Spectroscopy (PDS) experiments. The samples were characterized successively in their as-deposited state and after annealing at a temperature around 180 °C. The results indicate that the modes of H incorporation as well as the hydrogen content in the three series are completely different from those observed for the samples prepared by Plasma Enhanced Chemical Vapour Decomposition of pure silane (P.E.C.V.D.) at the same substrate temperature. The microstructure of the films is also different. The density of deep defects measured in the as-deposited is slightly higher in the former case. This density decreases significantly after annealing at 180 °C and becomes comparable to that obtained for a-Si:H samples prepared by P.E.C.V.D. at 250 °C at low deposition rates (~ 1 Å/s), with however a higher disorder in the R.F. sputtered films

Oxidation and crystallographic features of the new prototype structure Ti4NiSi4

Équipe 103 : Composés intermétalliques et matériaux hybridesInternational audienceThe oxidation resistance and the crystal structure of the new Ti4NiSi4 compound were investigated. This compound was manufactured both as a single-phase and as the outer layer of a protective coating for vanadium alloys. The recorded oxidation rates were very low at 650 degrees C and 750 degrees C in air, which represents a more severe environment than those envisaged for the targeted application: fuel cladding for sodium-cooled fast reactors. The powder XRD measurements performed at the synchrotron SOLEIL allowed for the crystallographic structure determination of Ti4NiSi4 (S.C. Pnma; a = 15.63931; b = 5.08321; c = 12.75151) with high confidence factors (R-wp = 0.07; R-Bragg = 0.067). Its structure consists of atomic planes stacking along the b-axis with planes at coordinates y = 0, 1/4, 1/2 and 3/4; it can therefore be considered as a pseudolamellar structure. It has been suggested that this peculiar feature induces a low activation energy for the phase transformation of Ti4NiSi4 into Ti4Ni4Si7, which thus renders the transformation possible at moderate temperature. This structural rearrangement is accompanied by the liberation of Ti and Si, which leads to the formation of both TiO2 and SiO2 oxidation products, which are responsible for the high environmental resistance observed at 650 degrees C in air

Study of the nanostructuration of ZrAu alloy near the ambient temperature by X-ray diffraction and thermal analyses

Abstract Spontaneous nanostructuration in air of the crystallized ZrAu alloy has been followed by X-ray diffraction using both synchrotron radiation and conventional laboratory X-ray source. This has allowed the study of the degradation of this compound from 25 to 150 • C with an accurate step in time adapted to the very fast oxidation kinetic (2 m of oxide layer per day at room temperature). From these experiments the activation energy (E a ) of the mechanism has been determined by the way of an original approach consisting in the analysis of the temperature dependent evolution of the integrated intensity of a selected ZrAu diffraction peak. Furthermore, this activation energy has been compared with the one obtained from thermogravimetric analysis. The two independent techniques giving consistent information, average activation energy of 55 kJ mol −1 was associated with this unusual phenomenon. We have shown that no significant oxidation behavior is observed under pure oxygen below 100 • C. The study of the phenomenon under pure oxygen, the microstructural analysis of the oxide layer and the study of the influence of relative humidity (RH) on the oxidation rate, allows us to attribute the oxidation mechanism to an atmospheric oxidation mechanism controlled by the dissociation of gaseous oxidative species at the alloy/air interface

Expression of matrix metalloproteinases in healthy and diseased human gingiva.

BACKGROUND, AIMS: The aim of our study was to investigate the patterns of several metalloproteinases (MMP-1, MMP-2 and MT1-MMP) mRNAs expression using a semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) and to correlate them with clinical parameters and bacteriological diagnosis in healthy versus diseased human gingiva. METHODS: To identify the cell origin of MMP production, in situ hybridization (ISH) was also performed for the MMPs on the same samples. 17 gingival biopsies were collected (13 affected by advanced periodontitis and 4 healthy used as controls) and plaque index, gingival index, pocket depth and bleeding on probing were measured. Subgingival microbial samples were also collected to be analysed by a DNA probe technique. The biopsies were processed both for RT-PCR and ISH. We also investigated a model for bacterial induced MMP expression in human gingival fibroblasts (HGF) infected by Eikenella corrodens. RESULTS: We found an expression of the mRNA encoding MMP-1 only in diseased gingiva but at low levels relative to beta-actin (mean+/-SD: diseased versus healthy: 0.013+/-0.024 versus 0). Although the frequencies and levels of mRNA encoding for MMP-2 or MT1-MMP are not significantly different between each group (mean+/-SD: 0.329+/-0.344 versus 0.137+/-0.219 for MMP-2; 0.485+/-0.374 versus 0.466+/-0.296 for MT1-MMP), using ISH, we observed an expression of both mRNAs in fibroblasts of pathological specimens at sites that histologically showed signs of chronic inflammation and connective tissue remodelling. In vitro infection of HGF by Eikenella corrodens stimulated 3-fold the production of the mRNA encoding MMP-2 while other mRNAs remained unchanged. CONCLUSION: Our results did not reveal significant differences in the expression of mRNAs encoding for the MMPs between healthy and periodontitis-affected patients, reflecting the great heterogeneity in the periodontal status of individuals. However, they indicate that gingival fibroblasts are an active source of MMP-2 production in response to a periopathogen

Study of the effect of high electronic excitations in quasicrystals irradiated with heavy ions

International audienceWe have studied the effect of irradiation with 900 MeV Pb and 780 MeV Xe ions on quasicrystals Al62Cu25.5Fe12.5 and the related cubic α-phase Al55Cu27Fe11Si 7. The fluences ranged from 1010 to 5.8×10 13 ions/cm2. Irradiations were performed at 80 K and at room temperature. The structural changes induced by the electronic excitations were studied by high-resolution X-ray diffraction. Whereas one might have expected the irradiations to induce important structural transformations, e.g. a phase transition from an icosahedral to a rhombohedral phase, only minor structural modifications are observed in the icosahedral phase and none in the α-phase. The defects created are not phasonic. Our results suggest a remarkable structural stability of these phases with respect to heavy-ion irradiation. © 2003 Elsevier B.V. All rights reserved

Oxygen storage capacity and structural flexibility of LuFe2O4Cx (0 < x< 0.5)

International audienceCombining functionalities in devices with high performances is a great challenge that rests on the discovery and optimization of materials. In this framework, layered oxides are attractive for numerous purposes, from energy conversion and storage to magnetic and electric properties. We demonstrate here the oxygen storage ability of ferroelectric LuFe2O4Cx within a large x range (from 0 to 0.5) and its cycling possibility. The combination of thermogravimetric analyses, X-ray diffraction and transmission electron microscopy evidences a complex oxygen intercalation/de-intercalation process with several intermediate metastable states. This topotactic mechanism is mainly governed by nanoscale structures involving a shift of the cationic layers. The ferrite is highly promising because absorption begins at a low temperature ( D 200 C), occurs in a low oxygen pressure and the uptake of oxygen is reversible without altering the quality of the crystals. The storage/release of oxygen coupled to the transport and magnetic properties of LnFe2O4 opens the door to new tunable multifunctional applications