Exploration de la coagulation plasmatique chez le chien essai du SCA 2000

Grâce à 99 échantillons de sang citrate de chien, la technique chronométrique classique "au crochet" de mesure des temps de Quick et de Céphaline avec Activateur est comparée à la technique utilisant le SCA 2000, un automate produit par le laboratoire Synbiotics. On obtient une très bonne corrélation entre les résultats même si on note parfois des divergences entre les deux méthodes pour des valeurs légèrement augmentées de temps de Céphaline avec activateur. Ces résultats sont donc compatibles avec une utilisation courante du SCA 2000 dans la pratique de la médecine vétérinaire

Finite element based surface roughness study for ohmic contact of microswitches

Finite element method (FEM) is used to model ohmic contact in microswitches. A determinist approach is adopted, including atomic force microscope (AFM) scanning real contact surfaces and generating rough surfaces with three-dimensional mesh. FE frictionless models are set up with the elastoplastic material and the simulations are performed with a loading-unloading cycle. Two material properties, gold and ruthenium, are studied in the simulations. The effect of roughness is investigated by comparing the models with several smoothing intensities and asperity heights. The comparison is quantitatively analyzed with relations of force vs. displacement, force vs. contact area and force vs. electrical contact resistance (ECR); further the evolution of spots in contact during a loading-unloading cycle is studied

BCB Based Packaging for Low Actuation Voltage RF MEMS Devices

This paper outlines the issues related to RF MEMS packaging and low actuation voltage. An original approach is presented concerning the modeling of capacitive contacts using multiphysics simulation and advanced characterization. A similar approach is used concerning packaging development where multi-physics simulations are used to optimize the process. A devoted package architecture is proposed featuring very low loss at microwave range

Hierarchical shape-based surface reconstruction for dense multi-view stereo

International audienceThe recent widespread availability of urban imagery has lead to a growing demand for automatic modeling from multiple images. However, modern image-based modeling research has focused either on highly detailed reconstructions of mostly small objects or on human-assisted simplified modeling. This paper presents a novel algorithm which automatically outputs a simplified, segmented model of a scene from a set of calibrated input images, capturing its essential geometric features. Our approach combines three successive steps. First, a dense point cloud is created from sparse depth maps computed from the input images. Then, shapes are robustly extracted from this set of points. Finally, a compact model of the scene is built from a spatial subdivision induced by these structures: this model is a global minimum of an energy accounting for the visibility of the final surface. The effectiveness of our method is demonstrated through several results on both synthetic and real data sets, illustrating the various benefits of our algorithm, its robustness and its relevance for architectural scenes

Pushing Structural Information into the Yeast Interactome by High-Throughput Protein Docking Experiments

The last several years have seen the consolidation of high-throughput proteomics initiatives to identify and characterize protein interactions and macromolecular complexes in model organisms. In particular, more that 10,000 high-confidence protein-protein interactions have been described between the roughly 6,000 proteins encoded in the budding yeast genome (Saccharomyces cerevisiae). However, unfortunately, high-resolution three-dimensional structures are only available for less than one hundred of these interacting pairs. Here, we expand this structural information on yeast protein interactions by running the first-ever high-throughput docking experiment with some of the best state-of-the-art methodologies, according to our benchmarks. To increase the coverage of the interaction space, we also explore the possibility of using homology models of varying quality in the docking experiments, instead of experimental structures, and assess how it would affect the global performance of the methods. In total, we have applied the docking procedure to 217 experimental structures and 1,023 homology models, providing putative structural models for over 3,000 protein-protein interactions in the yeast interactome. Finally, we analyze in detail the structural models obtained for the interaction between SAM1-anthranilate synthase complex and the MET30-RNA polymerase III to illustrate how our predictions can be straightforwardly used by the scientific community. The results of our experiment will be integrated into the general 3D-Repertoire pipeline, a European initiative to solve the structures of as many as possible protein complexes in yeast at the best possible resolution. All docking results are available at http://gatealoy.pcb.ub.es/HT_docking/

Towards high-resolution large-scale multi-view stereo

International audienceBoosted by the Middlebury challenge, the precision of dense multi-view stereovision methods has increased drastically in the past few years. Yet, most methods, although they perform well on this benchmark, are still inapplicable to large-scale data sets taken under uncontrolled conditions. In this paper, we propose a multi-view stereo pipeline able to deal at the same time with very large scenes while still producing highly detailed reconstructions within very reasonable time. The keys to these benefits are twofold: (i) a minimum s-t cut based global optimization that transforms a dense point cloud into a visibility consistent mesh, followed by (ii) a mesh-based variational refinement that captures small details, smartly handling photo-consistency, regularization and adaptive resolution. Our method has been tested on numerous large-scale outdoor scenes. The accuracy of our reconstructions is also measured on the recent dense multi-view benchmark proposed by Strecha et al., showing our results to compare more than favorably with the current state-of-the-art

Validation of Finite Element Structural Simulation for Ohmic Microcontact

AbstractIn the current literature, there is no model able to accurately predict the electrical resistance value of rough micro- contacts. Such model requires a coupled thermo-electro-structural analysis that is very difficult to validate in a straightforward manner. In the present approach, atomic force microscopy (AFM) scanned data of contact surface with roughness are used to build finite element (FE) model. As a first step towards multiphysics analysis, the aim of this study is to validate results of structural simulation of a rough gold micro-contact.A setup with a nanoindenter and a real microswitch is used to extract force-displacement curves. These results are compared to FE simulations which allow evaluating the effects of the main parameters. It is shown that the accuracy of these structural simulations is acceptable for an accurate evaluation of the electrical contact resistance