1,954 research outputs found

    Full NLO massive gauge boson pair production at the LHC

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    Electroweak gauge boson pair production is a very important process at the LHC as it probes the non-abelian structure of electroweak interactions and is a background process for many searches. We present full next-to-leading order predictions for the production cross sections and distributions of on-shell massive gauge boson pair production in the Standard Model, including both QCD and electroweak corrections. The hierarchy between the ZZ, WW and WZ channels, observed in the transverse momentum distributions, will be analyzed. We will also present a comparison with experimental data for the total cross sections including a study of the theoretical uncertainties.Comment: 4 pages, 4 figures. Proceeding of the inaugural conference "Windows on the Universe" (August 11-17, Quy Nhon, Vietnam) including updated results compared to arXiv:1307.433

    Espace et rapports de domination

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    International audienceDégagée de la plupart de ses contrepouvoirs depuis la fin des années 1980, le projet politique néolibéral et les inégalités qu’il renforce paraissent aujourd’hui sans remède. Est-il si difficile de ne pas céder à la résignation ou, pire, à l’indifférence ? Les outils pour identifier ces inégalités, les expliquer et les dénoncer ne manquent pas. La pensée critique connaît, en France comme ailleurs, un formidable renouveau. Dans toutes les disciplines des sciences sociales, l’apport de nos aînés est revisité et enrichi de nouvelles propositions pour se confronter aux injustices contemporaines, qui semblent rendues acceptables par des manipulations intellectuelles et des ficelles de plus en plus grossières.L’espace est, comme le temps et l’argent, un redoutable allié des dominants. Accaparé, exproprié, spolié, marchandisé, financiarisé, surveillé, refusé, l’espace se révèle être, à toutes les échelles et dans toutes ses configurations, une excellente clef de lecture de la situation des dominés. Confinement, relégation, enfermement en sont les modalités extrêmes, mais bien d’autres, plus subtiles et moins visibles, contribuent à pérenniser des rapports de force à ce point asymétriques qu’il n’est de meilleur terme pour les qualifier que celui de domination. Mais l’espace est aussi l’allié des dominés engagés dans des processus de résistance, de contestation ou de lutte contre l’ordre du capitalisme néolibéral. Dotés de ressources propres, les dominés construisent aussi des stratégies, individuelles ou collectives, qui prennent appui dans l’espace et peuvent faire de ce dernier une ressource pour se faire entendre ou se rendre visible.Dans un contexte académique mondial dominé par les travaux anglophones, en particulier ceux de la géographie radicale, cet ouvrage entend présenter la manière dont les chercheurs et chercheuses francophones travaillant sur les questions spatiales analysent les rapports sociaux de domination, qu’ils soient de classe, de race, de sexe, autant de rapports sociaux qui ont un fondement matériel. Plusieurs entrées thématiques sont explorées, qui renvoient à des champs de recherche bien identifiés : la question urbaine, les études sur le genre, le sexe, la sexualité et l’intersectionnalité, la question des migrations et celle des populations marginalisées et, enfin, l’environnement. Cet ouvrage témoigne donc de la grande vivacité des travaux francophones, tout en réaffirmant l’utilité de penser l’espace dans la critique sociale

    Osteoconductivity of bone substitutes with filament-based microarchitectures: Influence of directionality, filament dimension, and distance

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    Additive manufacturing can be applied to produce personalized bone substitutes. At present, the major three-dimensional (3D) printing methodology relies on fila­ment extrusion. In bioprinting, the extruded filament consists mainly of hydrogels, in which growth factors and cells are embedded. In this study, we used a lithogra­phy-based 3D printing methodology to mimic filament-based microarchitectures by varying the filament dimension and the distance between the filaments. In the first set of scaffolds, all filaments were aligned toward bone ingrowth direction. In a second set of scaffolds, which were derived from the identical microarchitecture but tilted by 90°, only 50% of the filaments were in line with the bone ingrowth direction. Testing of all tricalcium phosphate-based constructs for osteoconduction and bone regeneration was performed in a rabbit calvarial defect model. The results revealed that if all filaments are in line with the direction of bone ingrowth, filament size and distance (0.40–1.25 mm) had no significant influence on defect bridging. Howev­er, with 50% of filaments aligned, osteoconductivity declined significantly with an increase in filament dimension and distance. Therefore, for filament-based 3D- or bio-printed bone substitutes, the distance between the filaments should be 0.40 to 0.50 mm irrespective of the direction of bone ingrowth or up to 0.83 mm if perfectly aligned to it

    Strong normal-incidence infrared absorption in self-organized InAs/InAlAs quantum dots grown on InP(001)

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    International audienceInAs self-assembled quantum dots in InAlAs matrix grown on InP001 substrates have been fabricated using Stranski-Krastanov growth mode. A strong in-plane polarized intraband absorption in the 10.6-20 m wavelength region has been observed and ascribed to a transition from the ground electron state to an excited state confined in the layer plane along the 110 direction. The absorption at normal-incidence reaches 7.8% for ten layers of n-doped quantum dots. The oscillator strength of the intraband transition is comparable to that achieved in quantum wells for a conduction band intersubband transition. The dependence of the intraband absorption on carrier concentration and temperature suggests a quantum-wire type confinement potential

    3D-Printed HA-Based Scaffolds for Bone Regeneration: Microporosity, Osteoconduction and Osteoclastic Resorption

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    Additive manufacturing enables the realization of the macro- and microarchitecture of bone substitutes. The macroarchitecture is determined by the bone defect and its shape makes the implant patient specific. The preset distribution of the 3D-printed material in the macroarchitecture defines the microarchitecture. At the lower scale, the nanoarchitecture of 3D-printed scaffolds is dependent on the post-processing methodology such as the sintering temperature. However, the role of microarchitecture and nanoarchitecture of scaffolds for osteoconduction is still elusive. To address these aspects in more detail, we produced lithography-based osteoconductive scaffolds from hydroxyapatite (HA) of identical macro- and microarchitecture and varied their nanoarchitecture, such as microporosity, by increasing the maximum sintering temperatures from 1100 to 1400 °C. The different scaffold types were characterized for microporosity, compression strength, and nanoarchitecture. The in vivo results, based on a rabbit calvarial defect model showed that bony ingrowth, as a measure of osteoconduction, was independent from scaffold's microporosity. The same applies to in vitro osteoclastic resorbability, since on all tested scaffold types, osteoclasts formed on their surfaces and resorption pits upon exposure to mature osteoclasts were visible. Thus, for wide-open porous HA-based scaffolds, a low degree of microporosity and high mechanical strength yield optimal osteoconduction and creeping substitution. Based on our study, non-unions, the major complication during demanding bone regeneration procedures, could be prevented

    Functionalization of Ceramic Scaffolds with Exosomes from Bone Marrow Mesenchymal Stromal Cells for Bone Tissue Engineering

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    The functionalization of bone substitutes with exosomes appears to be a promising technique to enhance bone tissue formation. This study investigates the potential of exosomes derived from bone marrow mesenchymal stromal cells (BMSCs) to improve bone healing and bone augmentation when incorporated into wide open-porous 3D-printed ceramic Gyroid scaffolds. We demonstrated the multipotent characteristics of BMSCs and characterized the extracted exosomes using nanoparticle tracking analysis and proteomic profiling. Through cell culture experimentation, we demonstrated that BMSC-derived exosomes possess the ability to attract cells and significantly facilitate their differentiation into the osteogenic lineage. Furthermore, we observed that scaffold architecture influences exosome release kinetics, with Gyroid scaffolds exhibiting slower release rates compared to Lattice scaffolds. Nevertheless, in vivo implantation did not show increased bone ingrowth in scaffolds loaded with exosomes, suggesting that the scaffold microarchitecture and material were already optimized for osteoconduction and bone augmentation. These findings highlight the lack of understanding about the optimal delivery of exosomes for osteoconduction and bone augmentation by advanced ceramic scaffolds

    TPMS Microarchitectures for Vertical Bone Augmentation and Osteoconduction: An In Vivo Study

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    Triply periodic minimal surface microarchitectures (TPMS) were developed by mathematicians and evolved in all kingdoms of living organisms. Renowned for their lightweight yet robust attributes, TPMS structures find application in diverse fields, such as the construction of satellites, aircrafts, and electric vehicles. Moreover, these microarchitectures, despite their intricate geometric patterns, demonstrate potential for application as bone substitutes, despite the inherent gothic style of natural bone microarchitecture. Here, we produced three TPMS microarchitectures, D-diamond, G-gyroid, and P-primitive, by 3D printing from hydroxyapatite. We explored their mechanical characterization and, further, implanted them to study their bone augmentation and osteoconduction potential. In terms of strength, the D-diamond and G-gyroid performed significantly better than the P-primitive. In a calvarial defect model and a calvarial bone augmentation model, where osteoconduction is determined as the extent of bony bridging of the defect and bone augmentation as the maximal vertical bone ingrowth, the G-gyroid performed significantly better than the P-primitive. No significant difference in performance was observed between the G-gyroid and D-diamond. Since, in real life, the treatment of bone deficiencies in patients comprises elements of defect bridging and bone augmentation, ceramic scaffolds with D-diamond and G-gyroid microarchitectures appear as the best choice for a TPMS-based scaffold in bone tissue engineering

    Influence of Scaffold Microarchitecture on Angiogenesis and Regulation of Cell Differentiation during the Early Phase of Bone Healing: A Transcriptomics and Histological Analysis

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    The early phase of bone healing is a complex and poorly understood process. With additive manufacturing, we can generate a specific and customizable library of bone substitutes to explore this phase. In this study, we produced tricalcium phosphate-based scaffolds with microarchitectures composed of filaments of 0.50 mm in diameter, named Fil050G, and 1.25 mm named Fil125G, respectively. The implants were removed after only 10 days in vivo followed by RNA sequencing (RNAseq) and histological analysis. RNAseq results revealed upregulation of adaptive immune response, regulation of cell adhesion, and cell migration-related genes in both of our two constructs. However, significant overexpression of genes linked to angiogenesis, regulation of cell differentiation, ossification, and bone development was observed solely in Fil050G scaffolds. Moreover, quantitative immunohistochemistry of structures positive for laminin revealed a significantly higher number of blood vessels in Fil050G samples. Furthermore, µCT detected a higher amount of mineralized tissue in Fil050G samples suggesting a superior osteoconductive potential. Hence, different filament diameters and distances in bone substitutes significantly influence angiogenesis and regulation of cell differentiation involved in the early phase of bone regeneration, which precedes osteoconductivity and bony bridging seen in later phases and as consequence, impacts the overall clinical outcome

    Determination of uromodulin in human urine: influence of storage and processing

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    Background Uromodulin (Tamm-Horsfall protein) is the most abundant protein excreted in the urine under physiological conditions. It is exclusively produced in the kidney and secreted into the urine via proteolytic cleavage. The involvement of UMOD, the gene that encodes uromodulin, in rare autosomal dominant diseases, and its robust genome-wide association with the risk of chronic kidney disease suggest that the level of uromodulin in urine could represent a critical biomarker for kidney function. The structure of uromodulin is complex, with multiple disulfide bonds and typical domains of extracellular proteins. Methods Thus far, the conditions influencing stability and measurement of uromodulin in human urine have not been systematically investigated, giving inconsistent results. In this study, we used a robust, in-house ELISA to characterize the conditions of sampling and storage necessary to provide a faithful dosage of uromodulin in the urine. Results The levels of uromodulin in human urine were significantly affected by centrifugation and vortexing, as well as by the conditions and duration of storage. Conclusions These results validate a simple, low-cost ELISA and document the optimal conditions of processing and storage for measuring uromodulin in human urin
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