Wind turbine noise modeling: prediction of amplitude modulation and influence of atmospheric conditions

International audienceAeroacoustic noise from a wind turbine is mainly caused by the interaction between the wind turbine blade and the air flow. For a modern wind turbine, trailing edge noise is often the dominant noise source. In this paper, a detailed study of trailing edge noise is carried out using Amiet's frequency domain analytical source model. Model results are compared with experimental data. Features of wind turbine noise, such as amplitude modulation, ground directivity, influence of blade twist and pitch are studied. In the last part, the influence of realistic wind profiles is investigated. Wind shear is seen to increase the sound power level and the amplitude modulation

Effets météorologiques sur le bruit rayonné par les éoliennes

National audienceCette étude vise à expliquer les différences observées entre le bruit rayonné par une éolienne en champ proche et en champ lointain, en montrant l'influence des conditions météorologiques à la fois sur les sources de bruit d'une éolienne et sur la propagation de ce bruit dans l'atmosphère. Des données expérimentales ont été analysées afin d'obtenir des profils de vent et de température réalistes dans l'atmosphère. Dans certains cas, les profils de vent prédits par la théorie de la similitude différent fortement des profils mesurés, ce qui conduit à des prédictions erronées du bruit rayonné en champ proche (100m) comme en champ lointain (jusqu'à 1km). Le modèle de source montre que les plus fortes amplitudes de modulation sont obtenues dans la direction perpendiculaire au vent, alors que le modèle de propagation met en évidence des niveaux sonores plus importants dans la direction du vent pour des distances supérieures à 800mètres environ

Implication des Rho GTPases dans la survie cellulaire et l'adhérence : caractérisation d'une nouvelle voie d'activation de la Kinase Akt par Rac

Les RhoGTPases régulent une multitude de fonctions cellulaires. Les travaux présentés dans cette thèse mettent en évidence les interrelations entre deux phénomènes majeurs contrôlés par cette classe de molécules que sont la régulation de l’organisation du cytosquelette d’actine et la survie cellulaire. L’adhérence à la matrice extracellulaire joue un rôle actif dans la survie cellulaire essentiellement grâce à la kinase Akt qui assure la protection contre l’apoptose. La 1ère partie de ce travail a permis de caractériser une nouvelle voie d’activation d’Akt par la GTPase Rac, sollicitée dans des situations où l’interaction avec la matrice est réduite. Mise en évidence dans des cellules non adhérentes, nos travaux montrent que cette voie est également opérationnelle dans des cellules adhérentes mises en suspension. Ces observations sont supportées par la mise en évidence, in vitro, d’un complexe contenant Akt et Rac activées dans les cellules en suspension. Dans la 2ème partie, nous avons exploré le rôle des RhoGTPases dans la morphologie de cellules leucémiques atypiques, qui présentent des prolongements cytoplasmiques caractéristiques, les Tricholeucocytes. Nous démontrons une relation entre cette morphologie et un fort taux d’activation des GTPases Rac et Cdc42. Le traitement de ces cellules à l’IFN normalise ces activités par un mécanisme faisant intervenir RhoA et p53. Dans la 3ème partie, nous nous sommes intéressés à des structures d’adhérence appelés podosomes dont la formation est dépendante des GTPases Cdc42 et RhoA. Nous avons montré pour la première fois, l’existence de ces structures in vivo.RhoGTPases control a multitude of cellular functions. The work presented in this thesis highlights the relationships between two major phenomena controlled by this class of molecules which are the regulation of the organization of the actin cytoskeleton and cellular survival. Adhesion to the extracellular matrix plays an essential role in cellular survival thanks to the Akt kinase which ensures protection against the apoptose. The first part of this work led us to characterize a new pathway of activation of Akt by the GTPase Rac, requested when the interactions with the matrix are reduced. Highlighted in nonadherent cells, our work shows that this way is also operational in adherent cells grown in suspension. These observations are supported by the description, in vitro, of a complex containing Akt and Rac activated in the cells in suspension. In the 2nd part, we explored the role of RhoGTPases in the morphology of atypical leukemic cells, the Tricholeucocytes which present characteristic cytoplasmic protrusions. We show a relation between this morphology and a strong rate of activation of GTPases Rac and Cdc42. Treatment of these cells by IFN normalize the activities by a mechanism RhoA and p53 dependant. In the 3rd part, we were interested in structures of adherence called podosomes on which formation is dependent on GTPases Cdc42 and RhoA. We showed for the first time, the existence of these structures in vivo

Human Immunodeficiency Virus Type 1 Vif causes dysfunction of Cdk1 and CyclinB1: implications for cell cycle arrest

The two major cytopathic factors in human immunodeficiency virus type 1 (HIV-1), the accessory proteins viral infectivity factor (Vif) and viral protein R (Vpr), inhibit cell-cycle progression at the G2 phase of the cell cycle. Although Vpr-induced blockade and the associated T-cell death have been well studied, the molecular mechanism of G2 arrest by Vif remains undefined. To elucidate how Vif induces arrest, we infected synchronized Jurkat T-cells and examined the effect of Vif on the activation of Cdk1 and CyclinB1, the chief cell-cycle factors for the G2 to M phase transition. We found that the characteristic dephosphorylation of an inhibitory phosphate on Cdk1 did not occur in infected cells expressing Vif. In addition, the nuclear translocation of Cdk1 and CyclinB1 was disregulated. Finally, Vif-induced cell cycle arrest was correlated with proviral expression of Vif. Taken together, our results suggest that Vif impairs mitotic entry by interfering with Cdk1-CyclinB1 activation

CytoBinning:Immunological insights from multi-dimensional data

<div><p>New cytometric techniques continue to push the boundaries of multi-parameter quantitative data acquisition at the single-cell level particularly in immunology and medicine. Sophisticated analysis methods for such ever higher dimensional datasets are rapidly emerging, with advanced data representations and dimensional reduction approaches. However, these are not yet standardized and clinical scientists and cell biologists are not yet experienced in their interpretation. More fundamentally their range of statistical validity is not yet fully established. We therefore propose a new method for the automated and unbiased analysis of high-dimensional single cell datasets that is simple and robust, with the goal of reducing this complex information into a familiar 2D scatter plot representation that is of immediate utility to a range of biomedical and clinical settings. Using publicly available flow cytometry and mass cytometry datasets we demonstrate that this method (termed CytoBinning), recapitulates the results of traditional manual cytometric analyses and leads to new and testable hypotheses.</p></div

Transparent Danionella translucida as a genetically tractable vertebrate brain model

Understanding how distributed neuronal circuits integrate sensory information and generate behavior is a central goal of neuroscience. However, it has been difficult to study neuronal networks at single-cell resolution across the entire adult brain in vertebrates because of their size and opacity. We address this challenge here by introducing the fish Danionella translucida to neuroscience as a potential model organism. This teleost remains small and transparent even in adulthood, when neural circuits and behavior have matured. Despite having the smallest known adult vertebrate brain, D. translucida displays a rich set of complex behaviors, including courtship, shoaling, schooling, and acoustic communication. In order to carry out optical measurements and perturbations of neural activity with genetically encoded tools, we established CRISPR-Cas9 genome editing and Tol2 transgenesis techniques. These features make D. translucida a promising model organism for the study of adult vertebrate brain function at single-cell resolution

The Necrotic Signal Induced by Mycophenolic Acid Overcomes Apoptosis-Resistance in Tumor Cells

The amount of inosine monophosphate dehydrogenase (IMPDH), a pivotal enzyme for the biosynthesis of the guanosine tri-phosphate (GTP), is frequently increased in tumor cells. The anti-viral agent ribavirin and the immunosuppressant mycophenolic acid (MPA) are potent inhibitors of IMPDH. We recently showed that IMPDH inhibition led to a necrotic signal requiring the activation of Cdc42.Herein, we strengthened the essential role played by this small GTPase in the necrotic signal by silencing Cdc42 and by the ectopic expression of a constitutive active mutant of Cdc42. Since resistance to apoptosis is an essential step for the tumorigenesis process, we next examined the effect of the MPA–mediated necrotic signal on different tumor cells demonstrating various mechanisms of resistance to apoptosis (Bcl2-, HSP70-, Lyn-, BCR-ABL–overexpressing cells). All tested cells remained sensitive to MPA–mediated necrotic signal. Furthermore, inhibition of IMPDH activity in Chronic Lymphocytic Leukemia cells was significantly more efficient at eliminating malignant cells than apoptotic inducers.These findings indicate that necrosis and apoptosis are split signals that share few if any common hub of signaling. In addition, the necrotic signaling pathway induced by depletion of the cellular amount of GTP/GDP would be of great interest to eliminate apoptotic-resistant tumor cells

Mixed connective tissue disease : state of the art on clinical practice guidelines

© Author(s) (or their employer(s)) 2019. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.Mixed connective tissue disease (MCTD) is a complex overlap disease with features of different autoimmune connective tissue diseases (CTDs) namely systemic sclerosis, poly/dermatomyositis and systemic lupus erythematous in patients with antibodies targeting the U1 small nuclear ribonucleoprotein particle. In this narrative review, we summarise the results of a systematic literature research which was performed as part of the European Reference Network on Rare and Complex Connective Tissue and Musculoskeletal Diseases project, aimed at evaluating existing clinical practice guidelines (CPGs) or recommendations. Since no specific CPGs on MCTD were found, other CPGs developed for other CTDs were taken into consideration in order to discuss what can be applied to MCTD even if designed for other diseases. Three major objectives were proposed for the future development of CPGs: MCTD diagnosis (diagnostic criteria), MCTD initial and follow-up evaluations, MCTD treatment. Early diagnosis, epidemiological data, assessment of burden of disease and QOL aspects are among the unmet needs identified by patients.This publication was funded by the European Union’s Health Programme (2014-2020)info:eu-repo/semantics/publishedVersio

Translation correlations in anisotropically scattering media

Controlling light propagation across scattering media by wavefront shaping holds great promise for a wide range of communications and imaging applications. However, finding the right wavefront to shape is a challenge when the mapping between input and output scattered wavefronts (i.e. the transmission matrix) is not known. Correlations in transmission matrices, especially the so-called memory-effect, have been exploited to address this limitation. However, the traditional memory-effect applies to thin scattering layers at a distance from the target, which precludes its use within thick scattering media, such as fog and biological tissue. Here, we theoretically predict and experimentally verify new transmission matrix correlations within thick anisotropically scattering media, with important implications for biomedical imaging and adaptive optics.Comment: main article (18 pages) and appendices (6 pages