From medical data to simple virtual mock-up of scapulo-humeral joint

The surgical operations of shoulder joint are guided by various principles: osteosynthesis in the case of fracture, osteotomy in order to correct a deformation or to modify the functioning of the joint, or implementation of articular prosthesis. At the end of the twentieth century, many innovations in the domains of biomechanics and orthopedic surgery have been performed. Nevertheless, theoretical and practical problems may appear during the operation (visual field of surgeon is very limited, quality and shape of the bone is variable depending on the patient). Biomechanical criteria of success are defined for each intervention. For example, the installation with success of prosthetic implant will be estimated according to the degree of mobility of the new articulation, the movements of this articulation being function of the shape of the prosthesis and of its position on its osseous support. It is not always easy to optimize the preparation of the surgical operation for every patient, and a preliminary computer simulation would allow helping the surgeon in its choices and its preparation of the intervention. The techniques of virtual reality allow a high degree of immersion and allow envisaging the development of a navigation device during the operating act

Combined Characterisation of GOME and TOMS Total Ozone Using Ground-Based Observations from the NDSC

Several years of total ozone measured from space by the ERS-2 GOME, the Earth Probe Total Ozone Mapping Spectrometer (TOMS), and the ADEOS TOMS, are compared with high-quality ground-based observations associated with the Network for the Detection of Stratospheric Change (NDSC), over an extended latitude range and a variety of geophysical conditions. The comparisons with each spaceborne sensor are combined altogether for investigating their respective solar zenith angle (SZA) dependence, dispersion, and difference of sensitivity. The space- and ground-based data are found to agree within a few percent on average. However, the analysis highlights for both Global Ozone Monitoring Experiment (GOME) and TOMS several sources of discrepancies, including a dependence on the SZA at high latitudes and internal inconsistencies

Transcriptional Activation of REST by Sp1 in Huntington's Disease Models

In Huntington's disease (HD), mutant huntingtin (mHtt) disrupts the normal transcriptional program of disease neurons by altering the function of several gene expression regulators such as Sp1. REST (Repressor Element-1 Silencing Transcription Factor), a key regulator of neuronal differentiation, is also aberrantly activated in HD by a mechanism that remains unclear. Here, we show that the level of REST mRNA is increased in HD mice and in NG108 cells differentiated into neuronal-like cells and expressing a toxic mHtt fragment. Using luciferase reporter gene assay, we delimited the REST promoter regions essential for mHtt-mediated REST upregulation and found that they contain Sp factor binding sites. We provide evidence that Sp1 and Sp3 bind REST promoter and interplay to fine-tune REST transcription. In undifferentiated NG108 cells, Sp1 and Sp3 have antagonistic effect, Sp1 acting as an activator and Sp3 as a repressor. Upon neuronal differentiation, we show that the amount and ratio of Sp1/Sp3 proteins decline, as does REST expression, and that the transcriptional role of Sp3 shifts toward a weak activator. Therefore, our results provide new molecular information to the transcriptional regulation of REST during neuronal differentiation. Importantly, specific knockdown of Sp1 abolishes REST upregulation in NG108 neuronal-like cells expressing mHtt. Our data together with earlier reports suggest that mHtt triggers a pathogenic cascade involving Sp1 activation, which leads to REST upregulation and repression of neuronal genes

A chemical model for the atmosphere of hot Jupiters

Our purpose is to release a chemical network, and the associated rate coefficients, developed for the temperature and pressure range relevant to hot Jupiters atmospheres. Using this network, we study the vertical atmospheric composition of the two hot Jupiters (HD209458b, HD189733b) with a model that includes photolyses and vertical mixing and we produce synthetic spectra. The chemical scheme is derived from applied combustion models that have been methodically validated over a range of temperatures and pressures typical of the atmospheric layers influencing the observations of hot Jupiters. We compare the predictions obtained from this scheme with equilibrium calculations, with different schemes available in the literature that contain N-bearing species and with previously published photochemical models. Compared to other chemical schemes that were not subjected to the same systematic validation, we find significant differences whenever non-equilibrium processes take place. The deviations from the equilibrium, and thus the sensitivity to the network, are more important for HD189733b, as we assume a cooler atmosphere than for HD209458b. We found that the abundances of NH3 and HCN can vary by two orders of magnitude depending on the network, demonstrating the importance of comprehensive experimental validation. A spectral feature of NH3 at 10.5$\mu$m is sensitive to these abundance variations and thus to the chemical scheme. Due to the influence of the kinetics, we recommend the use of a validated scheme to model the chemistry of exoplanet atmospheres. Our network is robust for temperatures within 300-2500K and pressures from 10mbar up to a few hundreds of bars, for species made of C,H,O,N. It is validated for species up to 2 carbon atoms and for the main nitrogen species.Comment: 20 pages, 10 figures. Accepted for publication in Astronomy & Astrophysic

Suppression of MAPK11 or HIPK3 reduces mutant Huntingtin levels in Huntington's disease models.

Most neurodegenerative disorders are associated with accumulation of disease-relevant proteins. Among them, Huntington disease (HD) is of particular interest because of its monogenetic nature. HD is mainly caused by cytotoxicity of the defective protein encoded by the mutant Huntingtin gene (HTT). Thus, lowering mutant HTT protein (mHTT) levels would be a promising treatment strategy for HD. Here we report two kinases HIPK3 and MAPK11 as positive modulators of mHTT levels both in cells and in vivo. Both kinases regulate mHTT via their kinase activities, suggesting that inhibiting these kinases may have therapeutic values. Interestingly, their effects on HTT levels are mHTT-dependent, providing a feedback mechanism in which mHTT enhances its own level thus contributing to mHTT accumulation and disease progression. Importantly, knockout of MAPK11 significantly rescues disease-relevant behavioral phenotypes in a knockin HD mouse model. Collectively, our data reveal new therapeutic entry points for HD and target-discovery approaches for similar diseases

Interaction puissance-commande au sein des convertisseurs statiques

The electrical energy conversion is increasingly conversion is increasingly used in actual electrical systems. Also, the reduction of energical losses during the energy conversion has become an important objective. Thus, the electronic switch speed has been increased and allowed to reduce losses, but the technological implantation of components induces some electromagnetic compatibility problems. This is the reason of the interest of static converter designers in the Electromagnetic Compatibility. So, the study concerns the different risks of static converter malfunctioning due to its technology. Connections between energical sources (receiver and transmitter) and electronic switches (power unit and control unit) are often constituted of printed circuit traces, wires and copper bars. This connection is not perfect and its parasitic elements can disturb the static converter, even sometimes until its malfunctioning. The proposed study remains qualitative and unfolds in two times. In a first time, malfunctioning causes are shown according to the technology. For each case, risks are evaluated and design rules outlined. In a second time, proposed rules are applied onh a power static DC/DC converter, allowing to improve layout forward a better operating safety.Dans les systèmes électriques actuels, l'électronique de puissance est de plus en plus utilisée pour conditionner l'énergie électrique. Les convertisseurs statiques ont subi une évolution technologique importante notamment pour augmenter leur rendement et leur compacité. Ces performances sont essentiellemnt dues à l'accroissement de la rapidité des interrupteurs électroniques qui permert une réduction des pertes par commutation (absence de circuit d'aide à la commutation) et l'apparition de techniques de câblage nouvelles (hybrides, SMI...). Cependant, l'implantation technologique de ces composants modernes n'est pas sans poser quelques problèmes de compatibilité électromagnétique (perturbations de l'environnement, autoperturbation). La conception moderne de convertisseurs statiques ne permet plus d'ignorer les principes et les règles élémentaires de compatibilité électromagnétique (CEM) que ce soit dans la phase d'élaboration de prototype ou de préindustrialisation. C'est pourquoi les concepteurs de convertisseurs statiques s'intéressent à la Compatibilité Électromagnétique de leurs systèmes. De façon plus concrète, l'objectif de cet article est d'étudier les risques de dysfonctionnement des convertisseurs statiques dus à leur conception technologique. Les liaisons entre les sources d'énergie via les interrupteurs électroniques (de puissance et de commande) constituent ce que nous appelons la connectique. Le plus souvent, cette connectique est constituée de pistes de circuit imprimé, de fils ou encore de barres massives en cuivre ou aluminium. Cette connectique ne peut plus être considérée comme idéale étant donné les fréquences ou les grandeurs (fréquence, ${\rm d}I/{\rm d}t$, ${\rm d}V/{\rm d}t$) qui y transitent. Ses éléments parasites peuvent provoquer des troubles graves au sein du convertisseur statique allant même parfois jusqu'à son dysfonctionnement. L'étude proposée se déroule en deux temps. Dans un premier temps, les causes de dysfonctionnement sont mises en évidence et ordonnées en fonction de la technologie. Pour chaque cas, les risques sont évalués et des règles de conception ébauchées. Dans un deuxième temps, les règles proposées sont appliquées à un hacheur et sa commande et permettent de faire évoluer la conception du système vers une meilleure sûreté de fonctionnement

Dynamic lighting system for specular surface inspection

Specular surfaces inspection is a problem met frequently within the automatic control of metallic products. A tried technique to reveal the aspect defects is the imaging of the reflection of a structured lighting as Dark Field Illumination through the surface. In order to inspect the whole surface, an element of the lighting structure has to scan every part of the surface. In the case of important surface curvature gradients, entire scanning is not ensured if the object is moving in front of the static lighting. To overcome this limitation, an inverse process is proposed: the lighting structure is dynamic while the object is static. The scanning of the surface by the various lighting configurations enables the aspect control. A modeling of the surface to be inspected and defects to be detected is made. Inverse ray tracing is used to analyze the reflection of the lighting through the surface. This modeling enables to ensure the revealing of defects by respecting the chosen criteria of detection. A relation binding the physical size of defects and its size on the image is established. A metrological approach of the problem is then performed

The role of motion platform on postural instability and head vibration exposure at driving simulators

This paper explains the effect of a motion platform for driving simulators on postural instability and head vibration exposure. The sensed head level-vehicle (visual cues) level longitudinal and lateral accelerations (ax,sensed = ax_head and ay,sensed = ay_head, ayv = ay_veh and ayv = ay_veh) were saved by using a motion tracking sensor and a simulation software respectively. Then, associated vibration dose values (VDVs) were computed at head level during the driving sessions. Furthermore, the postural instabilities of the participants were measured as longitudinal and lateral subject body centre of pressure (XCP and YCP, respectively) displacements just after each driving session via a balance platform. The results revealed that the optic-head inertial level longitudinal accelerations indicated a negative non-significant correlation (r = −.203, p = .154 > .05) for the static case, whereas the optic-head inertial longitudinal accelerations depicted a so small negative non-significant correlation (r = −.066, p = .643 > .05) that can be negligible for the dynamic condition. The XCP for the dynamic case indicated a significant higher value than the static situation (t(47), p < .0001). The VDVx for the dynamic case yielded a significant higher value than the static situation (U(47), p < .0001). The optic-head inertial lateral accelerations resulted a negative significant correlation (r = −.376, p = .007 < .05) for the static platform, whereas the optic-head inertial lateral accelerations showed a positive significant correlation (r = .418, p = .002 < .05) at dynamic platform condition. The VDVy for the static case indicated a significant higher value rather than the dynamic situation (U(47), p < .0001). The YCP for the static case yielded significantly higher than the dynamic situation (t(47), p = .001 < 0.05)