Phase Transformations of Metallorganic Chemical Vapor Deposition Processed Alumina Coatings Investigated by In Situ Deflection

Phase transformations of Al2O3 films, deposited by metallorganic chemical vapor deposition from aluminium tri-isopropoxide on AISI 301 stainless steel, were investigated using an original technique of deflection associated with X-ray diffraction and electron microscopy. The samples were first oxidized at 1123 K in air to obtain a 0.9 m thick Cr2O3 protective oxide film on one side of the samples. Then, 1 m thick amorphous Al2O3 films were deposited on the opposite side at 823 K and 2 kPa. The deflection of such dissymmetrical samples was recorded during anisothermal treatments, consisting in slow heating to 1173 K in Ar atmosphere. The coefficient of thermal expansion of both the Cr2O3 and the amorphous Al2O3 films was determined to be 710−6 K−1 and 14.7 10−6 K−1, respectively. Crystallization kinetics of amorphous to mainly –Al2O3 become significant at temperatures equal or greater than 983 K. Transformation of metastable Al2O3 to –Al2O3 is initiated below 1173 K. It is demonstrated that deflection is a powerful tool for investigating the behavior of thin films deposited on a substrate and especially to reveal transformations occurring in these films during heat-treatments

Niaux – Grotte de Niaux et réseau Clastres

Identifiant de l'opération archéologique : Date de l'opération : 1970 (FP) Inventeur(s) : Andrieux Claude ; Bakalowicz Michel ; D'Hulst Dominique ; Mangin Alain ; Rouch Raymond ; Laboratoire souterrain du CNRS (Moulins) Le réseau Clastres est isolé du reste des galeries de la grotte de Niaux par une série de voûtes mouillantes permanentes. Lors de sa découverte en 1970 (Clottes, 1973), et à l'initiative de Dr L. Pales, une étude climatique fut engagée par Claude Andrieux (CNRS, Moulis). Il ..

Rapid thermal processing of CuInSe2 electroplated precursors for CuIn(S,Se)2-based thin film solar cells

International audienceDuring the elaboration of standard CISEL™cells, electroplated CuInSe2 precursors undergo a rapid thermal processing (RTP) in a sulfur-containing atmosphere to promote grain growth and enable sulfurization of the precursor. The aim of this work is to show how structural and morphological properties of the CuIn(S,Se)2-based solar cells can be modified with RTP parameters, namely temperature, heating rate, and sulfur addition. X-ray diffractograms show that the preferential (112) orientation of the electrodeposited CuInSe2 precursor is maintained after annealing but the coefficient of crystallographic texture can be modified with specific RTP parameters. It is also shown that the quantity of sulfur incorporated in the chalcopyrite lattice can be controlled and reaches almost pure CuInS2 according to the sulfur quantity used during the RTP. Another effect of the RTP annealing is to form a Mo(S,Se)2 layer which can lead to a quasi-ohmic contact between the molybdenum and the absorber. The properties of the Mo(S,Se)2 buffer layer are also studied according to the process parameters and an increase of the annealing temperature or of the sulfur concentration tends to increase the thickness of this laye

Effects of Transmission Belt Looseness on Electrical and Mechanical Measurements of an Induction Motor (best conference paper award)

This article explores the impact of belt looseness on electrical and mechanical quantities of a system driven by an induction motor and a belt-pulley transmission. The effects of this defect, for example the belt slipping or the apparition of spectral signatures in some measurements, are first investigated under steady state operation. Transient state tests are then performed to analyse, in the time domain, the system response to a step of the speed reference. The behaviour of different variables (slip,speed, currents, etc.) is studied for different health conditions and the increase of the belt looseness clearly impact the electric and mechanical variables’ waveforms. The experimental tests carried out in this study, under steady or transient state, show promising results for the diagnosis of belt degradations. Perspectives of this work are therefore detailed at the end of this paper

Tubulin tyrosination is a major factor affecting the recruitment of CAP-Gly proteins at microtubule plus ends

Tubulin-tyrosine ligase (TTL), the enzyme that catalyzes the addition of a C-terminal tyrosine residue to α-tubulin in the tubulin tyrosination cycle, is involved in tumor progression and has a vital role in neuronal organization. We show that in mammalian fibroblasts, cytoplasmic linker protein (CLIP) 170 and other microtubule plus-end tracking proteins comprising a cytoskeleton-associated protein glycine-rich (CAP-Gly) microtubule binding domain such as CLIP-115 and p150 Glued, localize to the ends of tyrosinated microtubules but not to the ends of detyrosinated microtubules. In vitro, the head domains of CLIP-170 and of p150 Glued bind more efficiently to tyrosinated microtubules than to detyrosinated polymers. In TTL-null fibroblasts, tubulin detyrosination and CAP-Gly protein mislocalization correlate with defects in both spindle positioning during mitosis and cell morphology during interphase. These results indicate that tubulin tyrosination regulates microtubule interactions with CAP-Gly microtubule plus-end tracking proteins and provide explanations for the involvement of TTL in tumor progression and in neuronal organization

In vitro and in vivo intracellular delivery of quantum dots by maurocalcine

International audienceMaurocalcine is a new member of the increasing family of cell penetrating peptides. We report for the first time that this peptide is able to deliver quantum dots inside a variety of cells, both in vitro and in vivo. In vivo, maurocalcine produces intracellular delivery of the nanoparticles without affecting the relative distribution of quantum dots within organs. The data stress out that maurocalcine can be used for intracellular delivery of functionalised nanoparticles in vivo

Stationary state of a heated granular gas: fate of the usual H-functional

We consider the characterization of the nonequilibrium stationary state of a randomly-driven granular gas in terms of an entropy-production based variational formulation. Enforcing spatial homogeneity, we first consider the temporal stability of the stationary state reached after a transient. In connection, two heuristic albeit physically motivated candidates for the non-equilibrium entropy production are put forward. It turns out that none of them displays an extremum for the stationary velocity distribution selected by the dynamics. Finally, the relevance of the relative Kullbach entropy is discussed.Comment: 17 pages, 2 figures, to be published in Physica

Mutations in TUBG1, DYNC1H1, KIF5C and KIF2A cause malformations of cortical development and microcephaly.

International audienceThe genetic causes of malformations of cortical development (MCD) remain largely unknown. Here we report the discovery of multiple pathogenic missense mutations in TUBG1, DYNC1H1 and KIF2A, as well as a single germline mosaic mutation in KIF5C, in subjects with MCD. We found a frequent recurrence of mutations in DYNC1H1, implying that this gene is a major locus for unexplained MCD. We further show that the mutations in KIF5C, KIF2A and DYNC1H1 affect ATP hydrolysis, productive protein folding and microtubule binding, respectively. In addition, we show that suppression of mouse Tubg1 expression in vivo interferes with proper neuronal migration, whereas expression of altered γ-tubulin proteins in Saccharomyces cerevisiae disrupts normal microtubule behavior. Our data reinforce the importance of centrosomal and microtubule-related proteins in cortical development and strongly suggest that microtubule-dependent mitotic and postmitotic processes are major contributors to the pathogenesis of MCD

Dynamic Regulation of Tgf-B Signaling by Tif1γ: A Computational Approach

TIF1γ (Transcriptional Intermediary Factor 1 γ) has been implicated in Smad-dependent signaling by Transforming Growth Factor beta (TGF-β). Paradoxically, TIF1γ functions both as a transcriptional repressor or as an alternative transcription factor that promotes TGF-β signaling. Using ordinary differential-equation models, we have investigated the effect of TIF1γ on the dynamics of TGF-β signaling. An integrative model that includes the formation of transient TIF1γ-Smad2-Smad4 ternary complexes is the only one that can account for TGF-β signaling compatible with the different observations reported for TIF1γ. In addition, our model predicts that varying TIF1γ/Smad4 ratios play a critical role in the modulation of the transcriptional signal induced by TGF-β, especially for short stimulation times that mediate higher threshold responses. Chromatin immunoprecipitation analyses and quantification of the expression of TGF-β target genes as a function TIF1γ/Smad4 ratios fully validate this hypothesis. Our integrative model, which successfully unifies the seemingly opposite roles of TIF1γ, also reveals how changing TIF1γ/Smad4 ratios affect the cellular response to stimulation by TGF-β, accounting for a highly graded determination of cell fate

Hadron Energy Reconstruction for the ATLAS Calorimetry in the Framework of the Non-parametrical Method

This paper discusses hadron energy reconstruction for the ATLAS barrel prototype combined calorimeter (consisting of a lead-liquid argon electromagnetic part and an iron-scintillator hadronic part) in the framework of the non-parametrical method. The non-parametrical method utilizes only the known $e/h$ ratios and the electron calibration constants and does not require the determination of any parameters by a minimization technique. Thus, this technique lends itself to an easy use in a first level trigger. The reconstructed mean values of the hadron energies are within $\pm 1$ of the true values and the fractional energy resolution is $[(58\pm3)/\sqrt{E}+(2.5\pm0.3)$. The value of the $e/h$ ratio obtained for the electromagnetic compartment of the combined calorimeter is $1.74\pm0.04$ and agrees with the prediction that $e/h > 1.7$ for this electromagnetic calorimeter. Results of a study of the longitudinal hadronic shower development are also presented. The data have been taken in the H8 beam line of the CERN SPS using pions of energies from 10 to 300 GeV.Comment: 33 pages, 13 figures, Will be published in NIM