Emergent hyperuniformity in periodically-driven emulsions

We report the emergence of large-scale hyperuniformity in microfluidic emulsions. Upon periodic driving confined emulsions undergo a first-order transition from a reversible to an irreversible dynamics. We evidence that this dynamical transition is accompanied by structural changes at all scales yielding macroscopic yet finite hyperuniform structures. Numerical simulations are performed to single out the very ingredients responsible for the suppression of density fluctuations. We show that as opposed to equilibrium systems the long-range nature of the hydrodynamic interactions are not required for the formation of hyperuniform patterns, thereby suggesting a robust relation between reversibility and hyperuniformity which should hold in a broad class of periodically driven materials.Comment: 5p, 3f, submitte

206 The time course of new T-wave ECG descriptors following single and double dose administration of Sotalol in healthy subjects

IntroductionThe aim of the study was to assess the time course effect of IKr blockade on ECG biomarkers of ventricular repolarization and to evaluate the accuracy of a fully automatic approach for QT duration evaluation.Methods12-lead digital ECG Holter were recorded in 38 healthy subjects (27 males, mean age=27.4±8.0 years) on baseline conditions (day 0) and after administration of 160 mg (day 1) and 320 mg (day 2) of d-l Sotalol. For each 24-hour period and each subject, ECGs were extracted every 10 minutes during the 4-hour period following drug dosage. Ventricular repolarization was characterized using 3 biomarker categories: conventional ECG time intervals, Principal Component Analysis (PCA) analysis on the T-wave, and fully automatic biomarkers computed from a mathematical model of the T-wave.ResultsQT interval was significantly prolonged starting 1h20 minutes after drug dosing with 160 mg and 1h 10 minutes after drug dosing with 320 mg. PCA ventricular repolarization parameters sotalol-induced changes were delayed (>3 hours). After sotalol dosing, the early phase of the T-wave changed earlier than the late phase prolongation. Globally, the modeled surrogate QT paralleled manual QT changes.The duration of manual QT and automatic surrogate QT were strongly correlated (R2=0.92, p<0.001). The Bland & Altman plot revealed a non-stationary systematic bias (bias =26.5ms ±1.96*SD = 16ms).ConclusionsChanges in different ECG biomarkers of ventricular repolarization display different kinetics after administration of a potent potassium channel blocker. These differences need to be taken into account when designing ventricular repolarization ECG studies

Filaments magnétiques : application à la conception de capteurs de forces et de nageurs microscopiques artificiels

The manuscript is devoted to two applications of chains of magnetic particles.The first chapter reports the design of force sensors between colloids. Various experiments are designed and performed to characterise the particles under investigation. Our experimental setup and signal processing techniques are described in detail. Finally, we compare this technique to previous ones.The second chapter describes the design and fabrication of the first microscopic artificial swimmers. Flexible magnetic filaments are created by aligning magnetic particles under a magnetic field and gluing them together by means of DNA strands. Their behaviour under a magnetic field is investigated. Subjected to an oscillating magnetic field, the filaments experience deformations so that a wave propagates along them, thereby generating a propulsive force, which we demonstrate through the motion of a spermatomorphic swimmer. Theoretical and numerical predictions are validated experimentally.Ce mémoire contient deux parties consacrées à deux applications des chaînes de particules magnétiques.Le premier chapitre décrit la conception d'un capteur de forces intercolloïdales. Nous présentons différentes expériences permettant de caractériser les particules utilisées. Nous décrivons ensuite la réalisation du montage expérimental et le traitement des données. Enfin, nous comparons cette technique aux autres techniques.Le second chapitre décrit la conception et la réalisation de nageurs à l'échelle microscopique. Nous fabriquons des filaments magnétiques flexibles en alignant des particules sous l'effet d'un champ magnétique. Les particules adjacentes sont reliées par des agents pontants. Nous avons étudié le comportement de ces filaments sous champ. Sous l'effet d'un champ magnétique oscillant, le filament se déforme : une onde se propage alors le long du filament, ce qui engendre une force propulsive, dont nous démontrons l'effet sur un nageur spermatomorphe. Enfin, nous vérifions des prédictions théoriques antérieures

Application des nouvelles méthodes d'apprentissage à la détection précoce d'anomalies en électrocardiographie

PARIS-BIUSJ-Thèses (751052125) / SudocPARIS-BIUSJ-Physique recherche (751052113) / SudocSudocFranceF

Filaments magnétiques (application à la conception de capteurs de forces et de nageurs microscopiques artificiels)

PARIS-BIUSJ-Thèses (751052125) / SudocPARIS-BIUSJ-Physique recherche (751052113) / SudocSudocFranceF

Ordered and Disordered Patterns in Two-Phase Flows in Microchannels

International audienc