Mycobacterium abscessus-Induced Granuloma Formation Is Strictly Dependent on TNF Signaling and Neutrophil Trafficking

Mycobacterium abscessus is considered the most common respiratory pathogen among the rapidly growing non-tuberculous mycobacteria. Infections with M. abscessus are increasingly found in patients with chronic lung diseases, especially cystic fibrosis, and are often refractory to antibiotic therapy. M. abscessus has two morphotypes with distinct effects on host cells and biological responses. The smooth (S) variant is recognized as the initial airway colonizer while the rough (R) is known to be a potent inflammatory inducer associated with invasive disease, but the underlying immunopathological mechanisms of the infection remain unsolved. We conducted a comparative stepwise dissection of the inflammatory response in S and R pathogenesis by monitoring infected transparent zebrafish embryos. Loss of TNFR1 function resulted in increased mortality with both variants, and was associated with unrestricted intramacrophage bacterial growth and decreased bactericidal activity. The use of transgenic zebrafish lines harboring fluorescent macrophages and neutrophils revealed that neutrophils, like macrophages, interact with M. abscessus at the initial infection sites. Impaired TNF signaling disrupted the IL8-dependent neutrophil mobilization, and the defect in neutrophil trafficking led to the formation of aberrant granulomas, extensive mycobacterial cording, unrestricted bacterial growth and subsequent larval death. Our findings emphasize the central role of neutrophils for the establishment and maintenance of the protective M. abscessus granulomas. These results also suggest that the TNF/IL8 inflammatory axis is necessary for protective immunity against M. abscessus and may be of clinical relevance to explain why immunosuppressive TNF therapy leads to the exacerbation of M. abscessus infections

Geometrically nonlinear analysis of shell structures using flat DKT shell elements

This report describes nonlinear analysis o t arbitrary thin shell structures subjected to static loads. The nonlinear analysis includes pre and post-buckling behavior for any degree ot nonlinearity due to large displacements and large rotations but small strains. The formulation includes some recent developments of piate and shell theories, automatic solution strategies for the nonlinear equations; all adapted for implementation in mini and micro-computers with virtual memory.supported by the Dav'd w. Taylor Naval Ship Research and Development Center througu work request N00167-85-WR5-0372http://archive.org/details/geometricallynon00batoN00167-85-WR5-0372N

Forming gas annealing of the carbon P-bC center in oxidized porous 3C-and 4H-SiC: an EPR Study

International audiencePrevious Electron Paramagnetic Resonance (EPR) studies identified the carbon dangling bond center as the main paramagnetic interface defect in 3C, 4H, 6H-SiC/SiO2, We demonstrate that this defect, called P-bC center, can be passivated by forming gas annealing at 400 degrees C. We have measured the PbC density at annealed 4H- and 3C-SiC/SiO2 interfaces and attributed its reduction to the transformation of the dangling bonds into EPR inactive C-H bonds. We have also studied the reverse phenomenon occurring during vacuum annealing at temperatures ranging from 600 degrees C up to 1000 degrees C and have determined a dissociation energy of approximate to 4.3 eV for the 3C and 4H polytypes

La spectroscopie de résonance ferromagnétique: fondements et applications

National audienc

Ferromagnetic resonance signature of metallic Co clusters in ferromagnetic ZnCoO thin films

International audienceHighly Co-doped Zn(0.7)Co(0.3)O thin films that can be reproducibly grown ferromagnetic by pulsed laser deposition have been investigated by optical absorption and ferromagnetic resonance spectroscopy (FMR). The saturation magnetization depends strongly on the O(2) content during the growth, the highest value being obtained for the lowest oxygen pressure conditions. Whereas the optical absorption spectra confirm the incorporation of Co as Co(Zn)(2+) in ZnO, the FMR spectra prove the additional presence of randomly oriented metallic Co nanoparticles. The angular variation in the FMR spectra allows us to determine in the most ferromagnetic film the effective magnetization, 4 pi M similar to 800 G at 300 K and the g factor, g=2.18, which is that of metallic Co. The fraction of the two species Co(Zn)(2+) and Co metal is estimated to be similar to 3:1 (C) 2008 American Institute of Physics

Ferromagnetic resonance study of GdN thin films with bulk and extended lattice constants

International audienceThe magnetic properties of GdN thin films with bulk and 2.4% extended lattice parameters have been studied by x-band ferromagnetic resonance (FMR) spectroscopy. Simple, anisotropic, single line FMR spectra are observed in the 0 to 18 kOe field range. Both films show an in-plane easy axis of magnetization due to the predominance of the shape related demagnetization fields. The films deposited on (100) Si substrates are strained with uniaxial anisotropy constants up to K-u=+5x10(6) erg/cm(3) at T=4 K. The lattice extension reduces the magnetization and decreases the Curie temperature from 69 K for the bulk films to 20 K for the films with extended lattice constants. Highly increased FMR linewidths are observed for the lattice extended films indicating large, local variations of the demagnetization fields

The contribution of stable isotopic tracing, narrow nuclear resonance depth profiling, and a simple stochastic theory of charged particle energy loss to studies of the dry thermal oxidation of SiC

15th International Workshop on Inelastic Ion-Surface Collisions (IISC-15), Ise Shima, JAPAN, OCT 17-22, 2004International audienceWe present the stochastic approach to calculating fast charged particle energy distributions when penetrating matter, and nuclear reaction yield curves obtained when the energy of a beam incident on a target is scanned about the energy of narrow nuclear resonances, such as O-18(p,alpha)N-15 at 151 keV. In particular we present new calculations that show the insensitivity of the final calculations to the detailed form of the energy loss distribution assumed for independent single ion-atom collisions. We present application of narrow resonance profiling with O-18 stable isotopic tracing to the study of the dry thermal oxidation mechanisms of silicon carbide, yielding insights into the process that cannot be obtained by other means. (c) 2005 Elsevier B.V. All rights reserved

La possibilité de la philosophie (étude sur l'interprétation hégélienne d'Héraclite)

L intention de cette thèse est triple : 1/ comprendre qui est Héraclite pour Hegel et évaluer la place qu occupe Héraclite dans le système hégélien; 2/ réfléchir à la pertinence actuelle de l interprétation hégélienne de ce philosophe dénommé l Obscur (ho skoteinos), même si l on sait aujourd hui que cette interprétation contient plusieurs difficultés philologiques; 3/ approfondir le thème du devenir à l aide de ces deux grands philosophes. Héraclite est pour Hegel le commencement, il est celui qui ouvre le champ d action de la philosophie. Plus précisément, par la mise en rapport de termes opposés (être et néant), il débute l histoire de la philosophie en brisant l identité parménidienne et débute aussi la philosophie elle-même, la Logique, en ce que son devenir expose l être à son autodétermination, ce devenir qui présuppose sans le savoir encore la contradiction et qui anticipe l infini véritable. Hegel nous rappelle donc qu en Héraclite, au contraire de ce qu en pense Heidegger qui retrouve en lui le silence de l être, se trouve la différence, la séparation, la force du négatif qui permet le dire de la vérité; il n est obscur que pour l entendement, mais jamais pour la raison. Héraclite a aussi une autre pertinence pour Hegel, soit celle d être un véritable penseur de la nature : le devenir saisi comme temps puis comme feu explique bien la mauvaise infinité naturelle, ce qui résume, en termes certes encore vagues, la pensée hégélienne de la nature. Bref, Héraclite ouvre la philosophie à sa vérité, cette vérité que Hegel a tenté de saisir en sa totalitéThe purpose of this thesis is threefold: 1 / understanding who is Heraclitus to Hegel and assess the place of Heraclitus in the Hegelian system, 2 / reflect on the current relevance of the interpretation of this philosopher Hegel called the Obscure (ho skoteinos), although we now know that this interpretation shows several philological problems; 3 / deepen the theme of the becoming with these two great philosophers. Heraclitus is, for Hegel, the beginning, he is the one that opens the scope of philosophy. Specifically, by setting the connexion between opposite terms (being and nothingness), he began the history of philosophy by breaking the Parmenidean identity. He also began philosophy itself, the Logic, in that his becoming exposes being to self-determination, which presupposes, without clearly knowing about it, contradiction and even anticipates the true infinite. Hegel reminds us that in Heraclitus, contrary to what Heidegger thinks, which is that he found in him the silence of being, lies the difference, the separation, the force that allows the negative to express the truth; he is obscure to understanding, but never to reason. Heraclitus holds another relevance for Hegel, in that of being a real thinker of nature: becoming apprehended as time and fire elucidates the spurious natural infinite, which summarizes, in terms admittedly still vague, the thought of Hegel on Nature. In short, Heraclitus opens philosophy to its truth, this truth that Hegel has tried to capture in its totalityPOITIERS-BU Droit Lettres (861942101) / SudocSudocFranceF