In Vivo Expression Pattern of MICA and MICB and Its Relevance to Auto-Immunity and Cancer

Non-conventional MHC class I MIC molecules interact not with the TCR, but with NKG2D, a C-type lectin activatory receptor present on most NK, γδ and CD8+ αβ T cells. While this interaction is critical in triggering/calibrating the cytotoxic activity of these cells, the actual extent of its in vivo involvement, in man, in infection, cancer or autoimmunity, needs further assessment. The latter has gained momentum along with the reported expansion of peripheral CD4+CD28−NKG2D+ T cells in rheumatoid arthritis (RA). We first initiated to extend this report to a larger cohort of not only RA patients, but also those affected by systemic lupus erythematosus (SLE) and Sjögren's syndrome (SS). In RA and SS, this initial observation was further tested in target tissues: the joint and the salivary glands, respectively. In conclusion and despite occasional and indiscriminate expansion of the previously incriminated T cell subpopulation, no correlation could be observed between the CD4+CD28−NKG2D+ and auto-immunity. Moreover, in situ, the presence of NKG2D matched that of CD8+, but not that of CD4+ T cells. In parallel, a total body tissue scan of both MICA and MICB transcription clearly shows that despite original presumptions, and with the exception of the central nervous system, both genes are widely transcribed and therefore possibly translated and membrane-bound. Extending this analysis to a number of human tumors did not reveal a coherent pattern of expression vs. normal tissues. Collectively these data question previous assumptions, correlating a tissue-specific expression/induction of MIC in relevance to auto-immune or tumor processes

Intérêt pronostique des mutations du gène N-RAS dans les leucémies aigües myéloïdes

STRASBOURG ILLKIRCH-Pharmacie (672182101) / SudocSudocFranceF

Recherche du couplage fort lumière-matière dans des microcavités nitrurées

CLERMONT FD-BCIU Sci.et Tech. (630142101) / SudocSudocFranceF

Ray-based Simulation of Defect Echoes for Ultrasonic Non Destructive Testing

AbstractIn order to compute flaw echoes, semi-analytical models commonly use scattering coefficients deduced from plane-wave approximations for incidence and observation waves. The proposed approach aims at improving the accuracy of methods used in the ultrasonic NDT module of the Civa simulation software. It relies on a representation of the ultrasonic field as a sum of rays, where plane wave approximations are applied to each ray, as opposed to the total field, allowing more accurate echo predictions. Several cases that illustrate the improvement brought by this new method are presented, with comparisons to results obtained by a finite element model

Determining ultrasonic propagation effective properties in complex heterogeneous media through microstructure-scale simulation

International audienceRay-based methods allow for fast computations of ultrasonic propagation in large components, and can be coupled with diffraction models to provide full simulations of NDE inspections. However, they do not account for complex interactions with highly heterogeneous propagation media, which can have a significant impact on inspection performances. In contrast, microstructure-scale finite element simulations consider these interactions but are too computationally intensive for large-scale simulations. The work presented in this communication aims at combining the advantages of these two approaches. Finite element simulations for small volumes of the microstructure are used to determine parameters such as effective velocities, attenuations, and scattering coefficients. A ray-based model uses these data to compute wave propagation over distances that are large compared to both wavelengths and characteristic microstructure sizes. A dedicated simulation module was implemented in a development version of the CIVA software. It generates random realizations of microstructures for given set of parameters, runs finite element computations, and post-processes their results to yield estimations of the properties of the macroscopic effective medium. The volumes considered by the finite element model are small enough to allow for 3D computations. Results were obtained for various types of microstructures, describing metals or concrete. This communication focuses on steel applications and on the impact of microstructure parameters on the simulation results. This approach is promising, and contributes to bridging the gap between microstructure-scale modelling and larger scale simulations.Acknowledgements: Some of the illustrative results presented in this communication were obtained as part of collaborative studies with EDF R&D and of the NEMESIS ANR

Simulation d’inspection ultrasonore en milieu fortement hétérogène : stratégies et outils de modélisation appliqués aux soudures austénitiques

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Simulation of ultrasonic TFM/FMC imaging for porosity clusters using multiple scattering modelling: Quantitative analyses and experimental comparisons

International audienceUltrasonic imaging using the Total Focusing Method (TFM) is very useful for locating and sizing defects accurately. However, when imaging clusters of pores, the results may be distorted by multiple scattering phenomena. Several simulations are performed in a 2D context considering different scattering model approaches: single scattering, single scattering including defect shadowing, and multiple scattering. In order to reproduce clusters of pores, we use sets of side-drilled holes to impose well-controlled properties (position and size) for comparison with experimental tests. Comparisons of the simulated TFM images with the experimental ones show qualitative and quantitative improvements when using the multiple scattering model, thanks in particular to a better consideration of shadowing and other interaction effects between defects

Expression of the rabbit cytochrome P450 aromatase encoding gene uses alternative tissue-specific promoters

International audienceThe aim of the present study was to analyse the tissue-specific expression of various promoter-derived transcripts from the gene encoding rabbit aromatase cytochrome P450. A new promoter, named I.r, was identified, and promoters II and I.r were sequenced. Promoter I.r-derived transcripts were found in preovulatory granulosa cells, corpus luteum, placenta and adipose tissue. An alternative splice variant of this transcript was found with tissue-specific preference. Tissue-specific expression of promoter-derived variants was studied in the ovary before and after ovulation. While the level of promoter II-derived transcript decreased dramatically after ovulation, that of promoter I.r-derived transcript remained unchanged, indicating that promoter II and promoter I.r were not controlled by a single regulation system. The existence of this dual system of regulation suggests that the rabbit ovary could be a useful model to study the promoter-specific regulation of aromatase