Collective motility of sperm in confined cells.

Mammalian fertility analysis is an important industrial issue because of the selection for breeding. This is one reason, beside fundamental interest, for which many studies analyse the individual motion of the spermatozoon (Gaffney et al. 2011). On the other hand, more recent reviews suggest that neither individual motion indicators or molecular markers can be clearly correlated to fertility (Kastelic and Thundathil 2008; Nathali and Turek 2011). This is why the industry still uses the scoring of sperm motility from the observation of semen sessile drop with a phase-contrast microscope. This observation of pure semen displays wave motion associated with millions of sperm moving together in circular waves and whirlpools. The moving speed, deformation and size of whirlpools were ranked and scored. Similar collective movements have also been observed in different biological suspensions above a certain concentration (Sokolov et al. 2007). But until today, there has been no clear analysis of the origin of the observed whirlpools dynamics in semen. In this article, we provide new insights on the origin of whirlpools. As the sessile drops do not permit a careful control of the micro-hydrodynamic boundary conditions associated with surface tension variations, we investigate collective effects in controlled rectangular cells confined span wise with 20 and 100mm depth. We mainly analyse the influence of the confinement and the concentration on the appearance of whirlpools

RESPUESTA DE UN DIPOLO MAGNÉTICO VERTICAL ANTE LA PRESENCIA DE CARACTERÍSTICAS PALEOAMBIENTALES DE SITIOS PREHISPANICOS

La utilización de corrientes inducidas en el subsuelo ha constituido, hoy día, un punto muy importante en el desarrollo de instrumentos complejos, capaces de cuantificar el nivel de conducción de carga eléctrica a través de un determinado volumen de terreno. En este trabajo se analiza la respuesta, como señal física, de ciertos dispositivos electromagnéticos basados en el principio fisico de inducción (dipolos magnéticos), ante la presencia de estructuras arqueológicas y ciertos elementos que formaron parte de los alrededores de uno de los centros político— religiosos más importantes de toda la civilización mesoamericana. Se presenta, como caso específico, la respuesta de un paleocanal obtenida en la zona oeste del Conjunto Principal de Copán - Ruinas, Honduras

Respuesta de un dipolo magnético vertical ante la presencia de características paleoambientales de sitios prehispanicos

La utilización de corrientes inducidas en el subsuelo ha constituido, hoy día, un punto muy importante en el desarrollo de instrumentos complejos, capaces de cuantificar el nivel de conducción de carga eléctrica a través de un determinado volumen de terreno. En este trabajo se analiza la respuesta, como señal física, de ciertos dispositivos electromagnéticos basados en el principio físico de inducción (dipolos magnéticos), ante la presencia de estructuras arqueológicas y ciertos elementos que formaron parte de los alrededores de uno de los centros político–religiosos más importantes de toda la civilización mesoamericana. Se presenta, como caso específico, la respuesta de un paleocanal obtenida en la zona oeste del Conjunto Principal de Copán – Ruinas, Honduras

An original phylogenetic approach identified mitochondrial haplogroup T1a1 as inversely associated with breast cancer risk in BRCA2 mutation carriers

Introduction: Individuals carrying pathogenic mutations in the BRCA1 and BRCA2 genes have a high lifetime risk of breast cancer. BRCA1 and BRCA2 are involved in DNA double-strand break repair, DNA alterations that can be caused by exposure to reactive oxygen species, a main source of which are mitochondria. Mitochondrial genome variations affect electron transport chain efficiency and reactive oxygen species production. Individuals with different mitochondrial haplogroups differ in their metabolism and sensitivity to oxidative stress. Variability in mitochondrial genetic background can alter reactive oxygen species production, leading to cancer risk. In the present study, we tested the hypothesis that mitochondrial haplogroups modify breast cancer risk in BRCA1/2 mutation carriers. Methods: We genotyped 22,214 (11,421 affected, 10,793 unaffected) mutation carriers belonging to the Consortium of Investigators of Modifiers of BRCA1/2 for 129 mitochondrial polymorphisms using the iCOGS array. Haplogroup inference and association detection were performed using a phylogenetic approach. ALTree was applied to explore the reference mitochondrial evolutionary tree and detect subclades enriched in affected or unaffected individuals. Results: We discovered that subclade T1a1 was depleted in affected BRCA2 mutation carriers compared with the rest of clade T (hazard ratio (HR) = 0.55; 95% confidence interval (CI), 0.34 to 0.88; P = 0.01). Compared with the most frequent haplogroup in the general population (that is, H and T clades), the T1a1 haplogroup has a HR of 0.62 (95% CI, 0.40 to 0.95; P = 0.03). We also identified three potential susceptibility loci, including G13708A/rs28359178, which has demonstrated an inverse association with familial breast cancer risk. Conclusions: This study illustrates how original approaches such as the phylogeny-based method we used can empower classical molecular epidemiological studies aimed at identifying association or risk modification effects.Peer reviewe

Genome-Wide Association Study in BRCA1 Mutation Carriers Identifies Novel Loci Associated with Breast and Ovarian Cancer Risk

BRCA1-associated breast and ovarian cancer risks can be modified by common genetic variants. To identify further cancer risk-modifying loci, we performed a multi-stage GWAS of 11,705 BRCA1 carriers (of whom 5,920 were diagnosed with breast and 1,839 were diagnosed with ovarian cancer), with a further replication in an additional sample of 2,646 BRCA1 carriers. We identified a novel breast cancer risk modifier locus at 1q32 for BRCA1 carriers (rs2290854, P = 2.7×10-8, HR = 1.14, 95% CI: 1.09-1.20). In addition, we identified two novel ovarian cancer risk modifier loci: 17q21.31 (rs17631303, P = 1.4×10-8, HR = 1.27, 95% CI: 1.17-1.38) and 4q32.3 (rs4691139, P = 3.4×10-8, HR = 1.20, 95% CI: 1.17-1.38). The 4q32.3 locus was not associated with ovarian cancer risk in the general population or BRCA2 carriers, suggesting a BRCA1-specific associat

The Eleventh and Twelfth Data Releases of the Sloan Digital Sky Survey: Final Data from SDSS-III

The third generation of the Sloan Digital Sky Survey (SDSS-III) took data from 2008 to 2014 using the original SDSS wide-field imager, the original and an upgraded multi-object fiber-fed optical spectrograph, a new near-infrared high-resolution spectrograph, and a novel optical interferometer. All of the data from SDSS-III are now made public. In particular, this paper describes Data Release 11 (DR11) including all data acquired through 2013 July, and Data Release 12 (DR12) adding data acquired through 2014 July (including all data included in previous data releases), marking the end of SDSS-III observing. Relative to our previous public release (DR10), DR12 adds one million new spectra of galaxies and quasars from the Baryon Oscillation Spectroscopic Survey (BOSS) over an additional 3000 deg2 of sky, more than triples the number of H-band spectra of stars as part of the Apache Point Observatory (APO) Galactic Evolution Experiment (APOGEE), and includes repeated accurate radial velocity measurements of 5500 stars from the Multi-object APO Radial Velocity Exoplanet Large-area Survey (MARVELS). The APOGEE outputs now include the measured abundances of 15 different elements for each star. In total, SDSS-III added 5200 deg2 of ugriz imaging; 155,520 spectra of 138,099 stars as part of the Sloan Exploration of Galactic Understanding and Evolution 2 (SEGUE-2) survey; 2,497,484 BOSS spectra of 1,372,737 galaxies, 294,512 quasars, and 247,216 stars over 9376 deg2; 618,080 APOGEE spectra of 156,593 stars; and 197,040 MARVELS spectra of 5513 stars. Since its first light in 1998, SDSS has imaged over 1/3 of the Celestial sphere in five bands and obtained over five million astronomical spectra. \ua9 2015. The American Astronomical Society

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

Diffraction of picosecond shear waves and measurement of their reflection coeffcient at a single interface : modeling and experiments

L'optoacoustique picoseconde est une technique qui permet de sonder la matière à l'échelle submicronique. L'objectif de ce travail est la synthèse d'ondes de cisaillement de fréquences GHz dans des couches minces isotropes pour l'analyse des propriétés transverses de la matière. C'est grâce à la diffraction du champ acoustique à l'intérieur du transducteur que ces ondes de cisaillement sont synthétisées. Nous exposons dans une première partie le développement des outils théoriques nécessaires à l'analyse de la répartition spatiale du champ acoustique généré lors de l'interaction laser-matière. Les diagrammes de directivité ainsi établis permettent de prévoir les directions de rayonnement privilégiées. Par une méthode de post traitement adaptée,nous synthétisons ensuite des ondes transverses dans ces directions particulières. Lorsque le transducteur est chargé par un milieu dont on cherche à connaître les propriétés transverses, les ondes de cisaillement synthétisées sont réfléchies à l'interface entre le transducteur et ce milieu. L'analyse du coefficient de réflexion permet alors de déterminer les propriétés mécaniques du milieu à sonder. Nous illustrons cette méthode numériquement et expérimentalement dans le cas d'une interface titane/glycérol.Picosecond optoacoustics is a technique that can probe properties of matter on a submicronscale. The aim of this work is to synthesize shear waves at GHz frequencies in a thin isotropiclayer in order to analyse its shear properties. Transverse waves are synthesized using diffraction.In the first part we develop theoretical tools in order to analyse the spatial repartition of theacoustic field generated by the laser-matter interaction. Directivity patterns predict the particulardirections for which amplitude of the shear waves is higher. Thus, we synthesized shearwaves in these particular directions using a dedicated post processing method. To investigateshear properties of a film lying on the sample, we study the reection of shear waves betweenthe transducer and the lying film. Starting with either simulated or experimental recordedwaveforms, we demonstrate the method in the specific case of the titanium/glycerol interface

Use of colistin in veterinary and human medicine : pharmacokinetic exploration and antimicrobial resistance issue

La colistine est un vieil antibiotique, utilisé à la fois en médecine humaine et vétérinaire. Cependant, l'arsenal antibiotique étant de plus en plus limité, la colistine apparait comme un des derniers remparts dans la lutte contre les bactéries multi-résistantes chez l'Homme. Afin de préserver l'efficacité de la colistine, deux problématiques ont été abordées dans cette thèse : (i) les risques de sélection de résistance à la colistine en lien avec la découverte fin 2015 d'un gène porté par un plasmide (mcr-1). Ainsi, l'impact de l'usage de colistine par voie orale en production porcine a été évalué in vivo et une absence de sélection a été observée dans nos conditions expérimentales. De façon similaire, l'usage (minoritaire) de colistine en médecine humaine comme prophylaxie de décontamination digestive sélective (SDD) a été étudié chez des rats hébergeant un microbiote intestinal humain. Les résultats préliminaires ne montrent pas non plus d'effet de sélection. (ii) le développement d'un modèle pharmacocinétique basé sur la physiologie (PBPK) chez le porc pour l'usage par voie systémique de la colistine et de sa prodrogue, le colistine méthanesulfonate (CMS). Ce modèle a permis d'explorer la distribution tissulaire du CMS et de la colistine, notamment au niveau rénal où la toxicité est la plus fréquente. Comme application de ce modèle, l'estimation des temps d'attente avant abattage lors d'usage de CMS chez le porc a été effectué. Enfin, la capacité des modèles PBPK à réaliser des extrapolations intra et inter-espèces a été utilisé pour adapter ce modèle chez l'adulte et l'enfant, afin de pouvoir prédire les concentrations plasmatiques de colistine lors d'un traitement.Colistin is an old antibiotic used in human and veterinary medicine. However, as less and less antibiotics are discovered, colistin is considered as a last-line antibiotic to fight against multi-drug resistant bacteria in human. In order to preserve the efficacy of colistin, two issues were investigated in this thesis:(i) Risks of selection of bacteria resistant to colistin, in conjunction with the discovery by the end of 2015 of a plasmid-mediated resistance gene (mcr-1). Thus, the impact of oral use of colistin in pigs was assessed in vivo and no selection was observed in our experimental conditions. Similarly, the use of colistin in human medicine for selective digestive decontamination was studied thanks to human flora‐associated rats. Preliminary results were also neither in favour of a selective effect of colistin.(ii) development of a physiologically-based pharmacokinetic model (PBPK) in pigs for the systemic use of colistin and its prodrug, the colistimethate sodium (CMS). This model provided a further insight into CMS and colistin tissue distribution, especially in kidneys where toxic effects are frequent. As a model application, the withdrawal period after use of CMS in pigs was estimated. Then, we used the ability of PBPK models to carry out intra and inter-species extrapolations in order to adapt this model in adults and children and eventually predict the plasmatic concentrations of colistin during a treatment with CMS