CYCLIST'S PEDALLING PARAMETERS USING KINEMATIC AND DYNAMIC MEASUREMENTS AND DISCRIMINATIVE VARIABLE ANALYSIS METHOD

INTRODUCTION: This work deals with the pedalling study of the cyclist in a seated position. The aim of this paper is two fold. Firstly a new kinematic and dynamic sensor is described to measure the absolute angle of the pedal and the applied forces in the sagittal plane. Secondly, the discriminative variable analysis method is presented and the experimental results are discussed. In this approach, the data have been obtained on three cyclists’ experience classes (3 cyclists per class). METHODS: The 360 degrees resistive sensor indicates the relative angle b of the pedal through a tooth belt. The crank angle a is measured with 8 photoelectric cells triggered by a marker fixed on the crank (cf. figure). In a previous work [Ref.], this variable was recorded with a camera which reveals to be of difficult use. Strain gauges attached to the pedals give the horizontal and tangential forces. This apparatus is fixed on a laboratory bicycle. Each cyclist pedals during 5 minutes with a constant velocity (1,5 r/s) and a constant power (150 W). Many variables (24) have been considered characterizing the measured data such as the amplitudes of the angular movements a and b, the variation of b with respect to a and Fourier components of the applied forces. RESULTS AND DISCUSSION: With this new sensor the applied power can be visua-lized in real time. Evaluating inter- and intra-variances taking the three cyclists classes into account, it can be shown that among the 24 variables considered, the two principal ones are the absolute pedal angle and the applied vertical force. Other classes could be presented as well. Thanks to the proposed method, pertinent variables enable to identify the pedalling parameters. CONCLUSION: Using this new kinematic and dynamic sensor and the above reported analysis, a significant analysis of the pedalling activity is feasible. Further work under progress will extend this procedure to a larger number of cyclists. Applications are pursued in sports with an amateur team to improve training techniques. REFERENCE: Deslandes J. et al. (1996). Etude expérimentale du pédalage à l'aide de la force appliquée sur la pédale et de son orientation. Arch. Phys. Bioch, 104, 614

Capacité musculaire du cou : évaluation isocinétique

Dans toutes les activités sportives, le cou est un segment corporel essentiel. L'étude proposée ici en mouvement isocinétique vise à caractériser la capacité musculaire du cou dans un mouvement de rotation latérale dans le plan frontal et dans un mouvement de flexion extension dans le plan sagittal. L'appareillage utilisé, Biodex®, est de type ergomètre à un bras avec un asservissement en vitesse du mouvement. Les premières expériences réalisées sur des sujets volontaires du laboratoire et les résultats sont en accord satisfaisant avec les valeurs de la littérature; cette première étude permet de valider l'adaptation d'un module spécifique de liaison entre la tête et l'ergomètre lors de cycles successifs, un cycle étant défini par un mouvement d'aller et retour de vitesse et d'amplitude imposé. Les résultats obtenus permettront ainsi l'évaluation de la capacité musculaire dans les sports où le cou a une importance capitale : Sports mécaniques, football, lutte, ..

Joint tripode coulissant de transmission automobile. Effort axial généré : essais et modèles

Les transmissions automobiles actuelles, organes de transmission de la puissance aux roues avants, sont constituées d'un joint tripode coulissant (côté moteur) nécessaire au débattement de suspension et d'un joint à billes (coté roue) nécessaire au braquage. Ces 2 joints sont reliés par un arbre intermédiaire. Le joint à billes est homocinétique alors que le joint tripode ne l'est pas exactement. Lors de la transmission de la puissance mécanique aux roues, le joint tripode coulissant génère un effort axial cyclique à la fréquence triple de la rotation de l'arbre d'entrée. Cet effort axial est à l'origine d'une vibration transverse au véhicule que les constructeurs automobiles cherchent à réduire. Nous présentons ici les mécanismes de génération de cet effort à l'aide de modèles en corps rigides recalés sur les essais. Les deux seuls paramètres externes influant présentés ici sont l'angle de brisure et le couple transmis

Telemedicine and dialysis

Colloque avec actes et comité de lecture. internationale.International audienceInformation found in the literature presents only marginal experiences concerning telemedicine in regards to peritoneal dialysis (PD). These experiences are limited to the transmission of data and/or images using new methods of communication. This article presents a new and innovative application of telemedicine in the field of PD and describes its characteristics in comparison to other telemedicine systems. In addition to optimizing the transmission of data via intra/internet, the DIATELIC (Interactive and Cooperative Monitoring of Dialysis Patients) system has an expert system designed to detect anomalies which can appear progressively and imperceptibly. This intelligent expert system uses six rules of interpretation simultaneously using basic initial data: Weight, blood pressure, differential blood pressure, orthostatic blood pressure, peritoneal ultrafiltration. These rules enable the system to give warning signs based on values which are pre-established or calculated using the averages of the previous 15 days. Routine use of this system operational now for over a year is conclusive. For the doctor, this system radically changes the way medical team follow-up on the patient. Daily access to the information concerning the patient resembles more a hospital-like setting and the integrated message service facilitates the contacts. For the patient, the sense of security derived from the expert system which notifies both the center and the patient in case of an anomaly is often mentioned. Telemedicine, which is in full development, will likely represent a major revolution for the public health system when the studies on the cost/benefit ratio reveal its utility

Télémédecine et Dialyse

National audienceLes données de la littérature font état d'expériences très marginales de télémédecine en dialyse péritonéale (DP). Ces expériences se limitent à la transmission de données et/ou d'images par les nouvelles voies de communication. Cette étude présente une application originale et innovante de la télémédecine dans le domaine de la DP. Le système DIATELIC (Surveillance Interactive et Coopérative des Dialysés) ajoute à l'optimisation de la transmission de données via intra/internet, un système expert élaboré détectant des anomalies d'apparition progressive voire imperceptible. Ce système expert "intelligent" utilise 5 règles d'interprétation simultanée utilisant des données initiales simples: Poids, tension artérielle (TA), TA différentielle, TA orthostatique, Ultrafiltration péritonéale. Ces règles déclenchent des alertes à partir de valeurs fixes pré- établies, mais également à partir des valeurs moyennes mesurées pendant les 15 jours précédents. L'utilisation routinière de ce système, opérationnel depuis plus d'un an, est concluante. Pour le médecin, l'utilisation d'un tel système change radicalement le suivi du malade en DP. L'accès quotidien aux données du malade se rapproche plus d'une surveillance de type hospitalière, et la messagerie intégrée facilite les contacts. Pour le malade, une impression de sécurité est constamment rapportée, le système expert prévenant à la fois le centre et le patient en cas d'anomalie. La télémédecine, en plein développement, représentera probablement un enjeu de santé publique majeur lorsque les études du rapport coût/bénéfice auront démontré son utilité

Activation of mutated TRPA1 ion channel by resveratrol in human prostate cancer associated fibroblasts (CAF)

Previous studies showed the effects of resveratrol (RES) on several cancer cells, including prostate cancer (PCa) cell apoptosis without taking into consideration the impact of the tumor microenvironment (TME). The TME is composed of cancer cells, endothelial cells, blood cells and cancer-associated fibroblasts (CAF), the main source of growth factors. The latter cells might modify in the TME the impact of RES on tumor cells via secreted factors. Recent data clearly show the impact of CAF on cancer cells apoptosis resistance via secreted factors. However, the effects of RES on PCa CAF have not been studied so far. We have investigated here for the first time the effects of RES on the physiology of PCa CAF in the context of TME. Using a prostate cancer CAF cell line and primary cultures of CAF from prostate cancers, we show that RES activates the N-terminal mutated Transient Receptor Potential Ankyrin 1 (TRPA1) channel leading to an increase in intracellular calcium concentration and the expression and secretion of growth factors (HGF and VEGF) without inducing apoptosis in these cells. Interestingly, in the present work, we also show that when the prostate cancer cells were co-cultured with CAF, the RES-induced cancer cell apoptosis was reduced by 40%, an apoptosis reduction canceled in the presence of the TRPA1 channel inhibitors. The present work highlights CAF TRPA1 ion channels as a target for RES and the importance of the channel in the epithelial-stromal crosstalk in the TME leading to resistance to the RES-induced apoptosis

Les mises en guerre de l'État

À partir de l’été 1914, les sociétés européennes paraissent brutalement saisies par la guerre et, ce faisant, saisies par l’État. C’est en son nom que des millions d’hommes vont s’affronter, sous l’uniforme, et que s’opère une gigantesque « mobilisation » des corps, des esprits et des ressources, pour reprendre le terme de l’époque toujours employé par les historiens et les historiennes. Cent ans plus tard, alors que tous les États ayant fait la guerre ont engagé de vastes programmes de commémoration, le moment semblait particulièrement opportun pour comprendre comment l’État parvient à faire la guerre et ce que la guerre fait à l’État. L’emprise de l’État est-elle immédiate, progressive, continue ou discontinue ? Connaît-elle des phases d’essoufflement, des ratés ? S’accompagne-t-elle de phénomènes parallèles de « déprise » ? Loin de toute généralité ou de toute extrapolation hasardeuse, est-il possible de repérer des formes de résistance ou d’évitement ? Interroger le processus de nationalisation des sociétés européennes, tel est l’un des enjeux de cet ouvrage pluridisciplinaire, largement ouvert dans l’espace et dans le temps autour du point de référence de 1914. Composé d’enquêtes bien circonscrites, l’ouvrage s’inscrit dans une histoire sociale de la guerre, et permet de questionner ce qui semble une évidence, au moins en France : la spectaculaire capacité de l’État à mobiliser, presque du jour au lendemain, une société tout entière.From the summer of 1914, European societies seem brutally seized by war and, as a consequence, seized by the State. In the name of the State, millions of men enrolled in the armed forces are to fight one another. Bodies, minds and resources are subjected to a gigantic "mobilization", a contemporary word still used by historians. A hundred years later, when all the warring States, as well as the States that were born from the conflict, are launching ambitious commemorative programs, the moment seems well chosen to study how the State wages war and, in return, how war transforms the State. As part of this vast topic, this international and multidisciplinary (history, political science, sociology) conference will address the invention of the War State, from the perspective of all the processes through which the event has – or does not have – an impact on the organisation, actions and conduct of the public power. The aim is to identify potential changes or limited adjustments, but always within situations of transition born from the conflict. Is the intensification of the State's hold on society immediate or gradual, continuous or discontinuous? Are there slower phases, failures? Is it paralleled with a loss of influence in other areas? Is it possible to detect forms of resistance or avoidance, while refraining from all generalizations and risky extrapolations? Questioning the process of nationalisation of European societies is one of the challenges of this multidisciplinary work, which is widely open in space and time around the 1914 key date. Composed of well-defined surveys, the book falls within a social perspective of war, and allows us to question what seems obvious, at least in France: the spectacular capacity of the State to mobilize, almost overnight, an entire society

Muscle cells of sporadic amyotrophic lateral sclerosis patients secrete neurotoxic vesicles

BACKGROUND: The cause of the motor neuron (MN) death that drives terminal pathology in amyotrophic lateral sclerosis (ALS) remains unknown, and it is thought that the cellular environment of the MN may play a key role in MN survival. Several lines of evidence implicate vesicles in ALS, including that extracellular vesicles may carry toxic elements from astrocytes towards MNs, and that pathological proteins have been identified in circulating extracellular vesicles of sporadic ALS patients. Because MN degeneration at the neuromuscular junction is a feature of ALS, and muscle is a vesicle-secretory tissue, we hypothesized that muscle vesicles may be involved in ALS pathology. METHODS: Sporadic ALS patients were confirmed to be ALS according to El Escorial criteria and were genotyped to test for classic gene mutations associated with ALS, and physical function was assessed using the ALSFRS-R score. Muscle biopsies of either mildly affected deltoids of ALS patients (n = 27) or deltoids of aged-matched healthy subjects (n = 30) were used for extraction of muscle stem cells, to perform immunohistology, or for electron microscopy. Muscle stem cells were characterized by immunostaining, RT-qPCR, and transcriptomic analysis. Secreted muscle vesicles were characterized by proteomic analysis, Western blot, NanoSight, and electron microscopy. The effects of muscle vesicles isolated from the culture medium of ALS and healthy myotubes were tested on healthy human-derived iPSC MNs and on healthy human myotubes, with untreated cells used as controls. RESULTS: An accumulation of multivesicular bodies was observed in muscle biopsies of sporadic ALS patients by immunostaining and electron microscopy. Study of muscle biopsies and biopsy-derived denervation-naïve differentiated muscle stem cells (myotubes) revealed a consistent disease signature in ALS myotubes, including intracellular accumulation of exosome-like vesicles and disruption of RNA-processing. Compared with vesicles from healthy control myotubes, when administered to healthy MNs the vesicles of ALS myotubes induced shortened, less branched neurites, cell death, and disrupted localization of RNA and RNA-processing proteins. The RNA-processing protein FUS and a majority of its binding partners were present in ALS muscle vesicles, and toxicity was dependent on the expression level of FUS in recipient cells. Toxicity to recipient MNs was abolished by anti-CD63 immuno-blocking of vesicle uptake. CONCLUSIONS: ALS muscle vesicles are shown to be toxic to MNs, which establishes the skeletal muscle as a potential source of vesicle-mediated toxicity in ALS

Muscle cells of sporadic amyotrophic lateral sclerosis patients secrete neurotoxic vesicles

Background: The cause of the motor neuron (MN) death that drives terminal pathology in amyotrophic lateral sclerosis (ALS) remains unknown, and it is thought that the cellular environment of the MN may play a key role in MN survival. Several lines of evidence implicate vesicles in ALS, including that extracellular vesicles may carry toxic elements from astrocytes towards MNs, and that pathological proteins have been identified in circulating extracellular vesicles of sporadic ALS patients. Because MN degeneration at the neuromuscular junction is a feature of ALS, and muscle is a vesicle-secretory tissue, we hypothesized that muscle vesicles may be involved in ALS pathology. Methods: Sporadic ALS patients were confirmed to be ALS according to El Escorial criteria and were genotyped to test for classic gene mutations associated with ALS, and physical function was assessed using the ALSFRS-R score. Muscle biopsies of either mildly affected deltoids of ALS patients (n = 27) or deltoids of aged-matched healthy subjects (n = 30) were used for extraction of muscle stem cells, to perform immunohistology, or for electron microscopy. Muscle stem cells were characterized by immunostaining, RT-qPCR, and transcriptomic analysis. Secreted muscle vesicles were characterized by proteomic analysis, Western blot, NanoSight, and electron microscopy. The effects of muscle vesicles isolated from the culture medium of ALS and healthy myotubes were tested on healthy human-derived iPSC MNs and on healthy human myotubes, with untreated cells used as controls. Results: An accumulation of multivesicular bodies was observed in muscle biopsies of sporadic ALS patients by immunostaining and electron microscopy. Study of muscle biopsies and biopsy-derived denervation-naïve differentiated muscle stem cells (myotubes) revealed a consistent disease signature in ALS myotubes, including intracellular accumulation of exosome-like vesicles and disruption of RNA-processing. Compared with vesicles from healthy control myotubes, when administered to healthy MNs the vesicles of ALS myotubes induced shortened, less branched neurites, cell death, and disrupted localization of RNA and RNA-processing proteins. The RNA-processing protein FUS and a majority of its binding partners were present in ALS muscle vesicles, and toxicity was dependent on the expression level of FUS in recipient cells. Toxicity to recipient MNs was abolished by anti-CD63 immuno-blocking of vesicle uptake. Conclusions: ALS muscle vesicles are shown to be toxic to MNs, which establishes the skeletal muscle as a potential source of vesicle-mediated toxicity in ALS