Simulation numérique d'une écoulement au-dessus d'une rampe à l'aide de la méthode des frontières immergées

Nous nous proposons d’étudier numériquement une géométrie étudiée dans le cadre du GDR Contrôle des Décollements, soit une plaque plane avec une rampe descendante, avec ou sans contrôle. Des simulations sont menées en 3D à l’aide d’un code incompressible qui utilise la formulation vitesse-tourbillon des équations de Navier-Stokes. Les écoulements à haute vitesse sont pris en compte à l’aide d’un modèle de sous-maille associée à la Simulation des Grandes Echelles (LES), le modèle d'échelles mixtes. La partie solide de la géométrie est calculée par pénalisation avec une méthode aux frontières immergées. Le maillage est alors cartésien et l’écoulement à l’intérieur du solide imposé à vitesse nulle. Le calcul du vecteur tourbillon aux frontières demande un soin particulier. Le contrôle peut être activé localement à la paroi et mimer les techniques d’aspiration (ou soufflage) ou de jets synthétiques. Nous associons ici dans un nouveau code des techniques présentes au LIMSI dans deux versions de ce code 3D incompressible, soit une version utilisée précédemment à nombres de Reynolds élevés pour simuler des écoulements externes (libres ou autour d’obstacles), avec ou sans contrôle, et une seconde version utilisée pour simuler des écoulements à des nombres de Reynolds plus raisonnables autour d’obstacles calculés par méthode de pénalisation. Un cas proche de la géométrie de référence est modélisé et les premiers essais sont effectués en petit 3D avec et sans contrôle par aspiration. Les objectifs de ce contrôle sont d’une part d’influencer la topologie de la recirculation au niveau de la rampe et d’autre part de réduire la trainée. Par la suite, d'autres cas seront simulés avec des dimensions plus réalistes par rapport à l'expérience de référence et des nombres de Reynolds plus élevés

Opposite effects of statins on mitochondria of cardiac and skeletal muscles: a ‘mitohormesis' mechanism involving reactive oxygen species and PGC-1

Aims Statins protect against cardiovascular-related mortality but induce skeletal muscle toxicity. To investigate mechanisms of statins, we tested the hypothesis that statins optimized cardiac mitochondrial function but impaired vulnerable skeletal muscle by inducing different level of reactive oxygen species (ROS). Methods and results In atrium of patients treated with statins, ROS production was decreased and oxidative capacities were enhanced together with an extensive augmentation of mRNAs expression of peroxisome proliferator-activated receptor gamma co-activator (PGC-1) family. However, in deltoid biopsies from patients with statin-induced muscular myopathy, oxidative capacities were decreased together with ROS increase and a collapse of PGC-1 mRNA expression. Several animal and cell culture experiments were conducted and showed by using ROS scavengers that ROS production was the triggering factor responsible of atorvastatin-induced activation of mitochondrial biogenesis pathway and improvement of antioxidant capacities in heart. Conversely, in skeletal muscle, the large augmentation of ROS production following treatment induced mitochondrial impairments, and reduced mitochondrial biogenesis mechanisms. Quercetin, an antioxidant molecule, was able to counteract skeletal muscle deleterious effects of atorvastatin in rat. Conclusion Our findings identify statins as a new activating factor of cardiac mitochondrial biogenesis and antioxidant capacities, and suggest the importance of ROS/PGC-1 signalling pathway as a key element in regulation of mitochondrial function in cardiac as well as skeletal muscle

Cardiopulmonary responses and muscle strength influence running performance parameters differently at different slopes

The analysis of trail-running performance appears to be complex and cardio-respiratory and muscular factors could have a variable importance depending on the inclination. Our study aims to determine the role of these parameters in performance. 13 subjects with heterogeneous levels participated in the study. They carried out 7 visits including 3 maximal aerobic speed (MAS) test at 1, 10 and 25% slope on treadmill, 3 endurance tests at 100% of the MAS reached at 1, 10 and 25% and an evaluation on isokinetic ergometer at different speeds (60-180-240 {\textdegree}/s). Gas exchange measured during the incremental tests. We were able to identify 2 groups, a performance and a recreational group. We observe a difference in VO2max, MAS at 1 and 10%, and maximal aerobic ascensional speed (MAaS) at 25%, between the 2 groups but no difference in VO2max and exhaustion time at 100% MAS between the different conditions (1-10-25%). Interestingly, at ventilatory thresholds the metabolic parameters, expressed as absolute or relative values, are similar between conditions (10-25%) while the ascensional speed are different. This study suggests that the measurement of ascensional speed is not as relevant as heart rate for controlling intensity given the variety of slope gradients in trail-running races

Best Practices and Pitfalls in Commercializing IVD-Applicable Biomarkers

Before biomarker discoveries can be commercially utilized in clinical laboratories, many studies and surveys need to be completed and many questions answered. Is there a market need? Is there enough scientific and clinical evidence to convince the end users? Is the biomarker patentable? Is the translation into a practical product feasible? Although commercial product development is not the focus of academic research, the route to reach the patients will almost always require a professional commercialization process. Understanding industry and end-user requirements is essential for the successful commercialization of new biomarker assays. The current handbook collects some of the best practices and pitfalls encountered at different phases of biomarker discovery, development, patent protection and technology transfer at universities, hospitals and research organizations. The focus is on in vitro diagnostics (IVD)-applicable biomarkers, i.e. markers intended to provide information on the health status of a person. The input for the collection has been sought from true-life practices: practices found in literature or taught by experts in the field; opinions and expertise of different stakeholders (end users, companies, technology transfer professionals, researchers, financiers); recommendations, regulation and laws; as well as practices learned the hard way, i.e. repeatedly failing somewhere in the process and later adapting the process for increased success. The main target group of the handbook comprises professionals working in Technology Transfer Offices (TTOs). The presented practices are yet not intended to be interpreted as strict rules but rather as a source of inspiration. Optimal ways to proceed with patenting and commercialization significantly vary between cases and circumstances.The handbook has been prepared within the EU-project Biomarker Commercialization (BIC) comprising 9 partners in the Baltic Sea Region (BSR) united with the same challenges, as well as the common objective of more efficiently bringing new and better IVD-applicable biomarkers from discovery into clinical use. The project's budget is EUR 2.55 million and is co-financed by the European Regional Development Fund through the Interreg Baltic Sea Region Programme with EUR 1.96 million

Comparison of Atmospheric and Lithospheric Culturable Bacterial Communities from Two Dissimilar Active Volcanic Sites, Surtsey Island and Fimmvörðuháls Mountain in Iceland

This research was funded by the Icelandic Research fund (IRF, RANNÍS) (174425-051). T.Š.-T. was supported by The Danish National Research Foundation (DNRF106, to the Stellar Astrophysics Centre, Aarhus University), the AUFF Nova programme (AUFF-E-2015-FLS-9-10), the Novo Nordisk Foundation (NNF19OC0056963) and the Villum Fonden (23175 and 37435). The Europlanet 2020 Research Infrastructure TA program (18-EPN4-059) funded T.Š.-T. participation in the sampling campaign.Surface microbes are aerosolized into the atmosphere by wind and events such as dust storms and volcanic eruptions. Before they reach their deposition site, they experience stressful atmospheric conditions which preclude the successful dispersal of a large fraction of cells. In this study, our objectives were to assess and compare the atmospheric and lithospheric bacterial cultivable diversity of two geographically different Icelandic volcanic sites: the island Surtsey and the Fimmvörðuháls mountain, to predict the origin of the culturable microbes from these sites, and to select airborne candidates for further investigation. Using a combination of MALDI Biotyper analysis and partial 16S rRNA gene sequencing, a total of 1162 strains were identified, belonging to 72 species affiliated to 40 genera with potentially 26 new species. The most prevalent phyla identified were Proteobacteria and Actinobacteria. Statistical analysis showed significant differences between atmospheric and lithospheric microbial communities, with distinct communities in Surtsey’s air. By combining the air mass back trajectories and the analysis of the closest representative species of our isolates, we concluded that 85% of our isolates came from the surrounding environments and only 15% from long distances. The taxonomic proportions of the isolates were reflected by the site’s nature and location.Peer reviewe

Opposite effects of statins on mitochondria of cardiac and skeletal muscles: a 'mitohormesis' mechanism involving reactive oxygen species and PGC-1

Aims Statins protect against cardiovascular-related mortality but induce skeletal muscle toxicity. To investigate mechanisms of statins, we tested the hypothesis that statins optimized cardiac mitochondrial function but impaired vulnerable skeletal muscle by inducing different level of reactive oxygen species (ROS). Methods and results In atrium of patients treated with statins, ROS production was decreased and oxidative capacities were enhanced together with an extensive augmentation of mRNAs expression of peroxisome proliferator-activated receptor gamma co-activator (PGC-1) family. However, in deltoid biopsies from patients with statin-induced muscular myopathy, oxidative capacities were decreased together with ROS increase and a collapse of PGC-1 mRNA expression. Several animal and cell culture experiments were conducted and showed by using ROS scavengers that ROS production was the triggering factor responsible of atorvastatin-induced activation of mitochondrial biogenesis pathway and improvement of antioxidant capacities in heart. Conversely, in skeletal muscle, the large augmentation of ROS production following treatment induced mitochondrial impairments, and reduced mitochondrial biogenesis mechanisms. Quercetin, an antioxidant molecule, was able to counteract skeletal muscle deleterious effects of atorvastatin in rat. Conclusion Our findings identify statins as a new activating factor of cardiac mitochondrial biogenesis and antioxidant capacities, and suggest the importance of ROS/PGC-1 signalling pathway as a key element in regulation of mitochondrial function in cardiac as well as skeletal muscles