On a model of magnetization switching driven by a spin current: a multiscale approach

International audienceWe study a model of magnetization switching driven by a spin current: the magnetization reversal can be induced without applying an external magnetic fi eld. We first write our one dimensional model in an adimensionalized form, using a small parameter $\epsilon$. We then explain the various time and space scales involved in the studied phenomena. Taking into account these scales, we fi rst construct an appropriate numerical scheme, that allows us to recover numerically various results of physical experiments. We then perform a formal asymptotic study as $\epsilon$ tends to 0, using a multiscale approach and asymptotic expansions. We thus obtain approximate limit models that we compare with the original model via numerical simulations

Thiol-ene photo-click collagen-PEG hydrogels: impact of water-soluble photoinitiators on cell viability, gelation kinetics and rheological properties

Thiol-ene photo-click hydrogels were prepared via step-growth polymerisation using thiol-functionalised type-I collagen and 8-arm poly(ethylene glycol) norbornene-terminated (PEG-NB), as a potential injectable regenerative device. Type-I collagen was thiol-functionalised by a ring opening reaction with 2-iminothiolane (2IT), whereby up to 80 Abs.% functionalisation and 90 RPN% triple helical preservation were recorded via 2,4,6-Trinitrobenzenesulfonic acid (TNBS) colorimetric assay and circular dichroism (CD). Type, i.e., either 2-Hydroxy-1-[4-(2-hydroxyethoxy) phenyl]-2-methyl-1-propanone (I2959) or lithium phenyl-2,4,6-trimethylbenzoylphosphinate (LAP), and concentration of photoinitiator were varied to ensure minimal photoinitiator-induced cytotoxicity and to enable thiol-ene network formation of collagen-PEG mixtures. The viability of G292 cells following 24 h culture in photoinitiator-supplemented media was largely affected by the photoinitiator concentration, with I2959-supplemented media observed to induce higher toxic response (0.1 → 0.5% (w/v) I2959, cell survival: 62 → 2 Abs.%) compared to LAP-supplemented media (cell survival: 86 → 8 Abs.%). In line with the in vitro study, selected photoinitiator concentrations were used to prepare thiol-ene photo-click hydrogels. Gelation kinetics proved to be largely affected by the specific photoinitiator, with LAP-containing thiol-ene mixtures leading to significantly reduced complete gelation time (τ: 187 s) with respect to I2959-containing mixtures (τ: 1683 s). Other than the specific photoinitiator, the photoinitiator concentration was key to adjusting the hydrogel storage modulus (G’), whereby 15-fold G’ increase (232 → 3360 Pa) was observed in samples prepared with 0.5% (w/v) compared to 0.1% (w/v) LAP. Further thiol-ene formulations with 0.5% (w/v) LAP and varied content of PEG-NB were tested to prepare photo-click hydrogels with porous architecture, as well as tunable storage modulus (G’: 540–4810 Pa), gelation time (τ: 73–300 s) and swelling ratio (SR: 1530–2840 wt %). The photoinitiator-gelation-cytotoxicity relationships established in this study will be instrumental to the design of orthogonal collagen-based niches for regenerative medicine

Modernisation et retour au[x] source[s] du métier de pharmacien à travers l'automatisation et la création de gammes cosmétiques au sein de l'officine

CHATENAY M.-PARIS 11-BU Pharma. (920192101) / SudocPARIS-BIUP (751062107) / SudocSudocFranceF

Effets électrostatiques sur le comportement des états excités de benzophénones chargées en solution micellaire

Deux photoamorceurs de type benzophénone portant des groupes ioniques qui leur confèrent une solubilité importante en phase aqueuse sont étudiés en solution micellaire. Les positions respectives de ces deux composés sont déterminées par rapport aux zones de la structure micro-hétérogène en utilisant la spectroscopie UV et sont comparées à celle de la benzophénone elle-même. On évalue ensuite l'importance de la localisation de ces trois produits sur le comportement de leurs états excités et sur les processus de désactivation habituellement impliqués dans les photopolymérisations en solution micellaire : formation de paires radicalaires avec le surfactant, désactivation par les monomères ou par les amines. On montre enfin le rôle important joué par les interactions électrostatiques qui apparaissent entre les différentes entités chargées qui interviennent dans les processus étudiés

Assessment of signal quality measured with a smart 12‐lead ECG acquisition T‐shirt

International audienceBackground: Ambulatory ECG monitoring is typically achieved using portable devices with limited number of surface leads, autonomy, and length of recording. Smart garments with multiple conductive textile electrodes provide great promise to perform continuous and comfortable ECG monitoring.Methods: We evaluated the ECG signal quality measured on healthy subjects with a smart 12-lead ECG acquisition T-shirt or a 12-lead Holter recording. ECG signals were recorded during 3 min with both techniques in three resting positions (supine, seated, standing) and while walking. Three readers independently assessed ECG patterns and evaluated the denoising of the isoelectric line, the distinction of p waves, R peaks and RR intervals, and the possible appreciation of cardiac rhythm in at least 3 leads.Results: Thirty healthy subjects (70% males, 29.5 ± 7.8 years) were enrolled in the study. For all three resting conditions, cardiac rhythm was appreciated in 100% of recordings with distinction of p waves, R peaks, and isoelectric line in >97% of recordings. Appreciation of cardiac rhythm was lower in the walking conditions with both techniques (53.3% vs. 46.7%, Holter vs. smart T-shirt, p = .60) mainly due to difficulties to distinguish p waves. These results were consistent across both genders. All ECG parameters (heart rate, PR, QRS and QTC intervals) were comparable between both techniques. No skin irritation was seen with the textile electrodes.Conclusions: A smart T-shirt with 13 textiles electrodes allows short-duration 12-lead ECG acquisition with quality levels comparable to Holter recordings. The novel device should now be evaluated for long-term non-invasive ECG monitoring

HTA essentielle résistante : place de la spironolactone

International audienceResistant hypertension is defined as uncontrolled blood pressure (BP) despite three antihypertensive agents including a diuretic (thiazide diuretic if renal function is normal or loop diuretic in case of chronic kidney disease with eGFR<30mL/min), a renin-angiotensin system blocker (ARB or ACEI) and a calcium channel blocker, at optimal doses. Resistance must be confirmed by out-of-office measurements (ambulatory blood pressure monitoring or home blood pressure monitoring) and patients should be asked about treatment compliance and excessive salt or alcohol intake. If the diagnosis of resistant hypertension is confirmed, the patient should be referred to a hypertension specialist to screen for secondary causes of hypertension as they are frequent in this context. If essential resistant hypertension is confirmed, the mineralocorticoid receptor antagonist, spironolactone, should be added (25 to 50mg daily). In the event of a contraindication to spironolactone, or if adverse effects occur, a beta-blocker, an alpha-blocker, or a centrally acting antihypertensive drug should be prescribed

Atrial Fibrillation Detection With an Analog Smartwatch: Prospective Clinical Study and Algorithm Validation

BackgroundAtrial fibrillation affects approximately 4% of the world’s population and is one of the major causes of stroke, heart failure, sudden death, and cardiovascular morbidity. It can be difficult to diagnose when asymptomatic or in the paroxysmal stage, and its natural history is not well understood. New wearables and connected devices offer an opportunity to improve on this situation. ObjectiveWe aimed to validate an algorithm for the automatic detection of atrial fibrillation from a single-lead electrocardiogram taken with a smartwatch. MethodsEligible patients were recruited from 4 sites in Paris, France. Electrocardiograms (12-lead reference and single lead) were captured simultaneously. The electrocardiograms were reviewed by independent, blinded board-certified cardiologists. The sensitivity and specificity of the algorithm to detect atrial fibrillation and normal sinus rhythm were calculated. The quality of single-lead electrocardiograms (visibility and polarity of waves, interval durations, heart rate) was assessed in comparison with the gold standard (12-lead electrocardiogram). ResultsA total of 262 patients (atrial fibrillation: n=100, age: mean 74.3 years, SD 12.3; normal sinus rhythm: n=113, age: 61.8 years, SD 14.3; other arrhythmia: n=45, 66.9 years, SD 15.2; unreadable electrocardiograms: n=4) were included in the final analysis; 6.9% (18/262) were classified as Noise by the algorithm. Excluding other arrhythmias and Noise, the sensitivity for atrial fibrillation detection was 0.963 (95% CI lower bound 0.894), and the specificity was 1.000 (95% CI lower bound 0.967). Visibility and polarity accuracies were similar (1-lead electrocardiogram: P waves: 96.9%, QRS complexes: 99.2%, T waves: 91.2%; 12-lead electrocardiogram: P waves: 100%, QRS complexes: 98.8%, T waves: 99.5%). P-wave visibility accuracy was 99% (99/100) for patients with atrial fibrillation and 95.7% (155/162) for patients with normal sinus rhythm, other arrhythmias, and unreadable electrocardiograms. The absolute values of the mean differences in PR duration and QRS width were <3 ms, and more than 97% were <40 ms. The mean difference between the heart rates from the 1-lead electrocardiogram calculated by the algorithm and those calculated by cardiologists was 0.55 bpm. ConclusionsThe algorithm demonstrated great diagnostic performance for atrial fibrillation detection. The smartwatch’s single-lead electrocardiogram also demonstrated good quality for physician use in daily routine care. Trial RegistrationClinicalTrials.gov NCT04351386; http://clinicaltrials.gov/ct2/show/NCT0435138

Ferrocene-based (photo)redox polymerization under long wavelengths

WOS:000462077800002 Electronic supplementary information (ESI) available: Fig. S1 and S2: synthesis of the different Fe complexes; Fig. S3: emission spectrum of LD@785 nm; Fig. S4: frontier molecular orbitals and UV-vis calculated spectra of the Fe complexes; Fig. S5: photopolymerization profiles upon LED@660 and 530 nm; Fig. S6: other redox polymerizations; Fig. S7: otherInternational audienceFerrocene-based photoredox catalysis is proposed here for the first time. Aryl radicals generated from a Fe(II)*/Ar2I+ reaction can be used as initiating species for efficient free radical photopolymerization of methacrylate resins. Remarkably, these photoredox catalysts can also be used for redox free radical polymerization (without light) in combination with ammonium persulfate for unique access to dual cure (photochemical/thermal redox) systems. The addition of a third component (amine, phosphine or vitamin C reducing agents) enables the regeneration of the catalysts and greatly enhances the radical generation. The motivation with these dual cure systems is to develop orthogonal chemistries where a latent redox polymerization (without light) is able to cure any thickness of polymers (or composite) in combination with fast photopolymerization processes in the irradiated areas. Chemical mechanisms will be discussed in detail using cyclic voltammetry, electron spin resonance spin trapping (ESR-ST), UV-vis-NIR spectroscopy, free energy calculations and molecular modeling at the density functional theory (DFT) level. This study represents, to the best of our knowledge, the first photochemically active iron catalysts that are also efficient in thermal redox catalysis

Représentations et identités sexuelles dans le théâtre de Shakespeare

Dans la perspective historicisante, c’est ce qui dans le texte demeure quelque peu étranger à son lecteur qui constitue sa plus grande richesse. Ce que le texte de théâtre shakespearien dit du genre s’inscrit pleinement dans cette perspective pour un critique contemporain, et la prise en compte des conditions matérielles de la représentation théâtrale – au premier rang desquelles figure l’exclusion des femmes du plateau – ne saurait à elle seule permettre d’en restituer toute la richesse. Le discours sur le genre que constituent les personnages, leurs mises en situation, leurs répliques et leur dimension évolutive s’articule en effet à un certain nombre de définitions identitaires sexuées dans l’Angleterre élisabéthaine et jacobéenne, attestées par d’autres sources primaires, et codifiées pour les besoins du support théâtral, c’est-à-dire rendues visibles et lisibles pour les spectateurs. Une double logique guide donc ces mises en scène de l’identité sexuelle sur le plateau shakespearien : on y décèle d’une part un certain nombre d’éléments socio-culturels aisément reconnaissables pour le spectateur, qui construisent une image dramatique correspondant à la codification historique de l’identité sexuelle à la fin du XVIe et au début du XVIIe siècle, et d’autre part, il s’y manifeste un ensemble de références à l’immédiateté du plateau et à l’univers potentiellement indifférencié qu’il constitue, par sa dimension unisexe masculine. Lorsque se constitue un univers dramatique, c’est l’image fidèle à la codification sexuelle qui prédomine, en vertu du principe aristotélicien de mimesis. A contrario, lorsque la théâtralité est affichée, les repères du genre se brouillent, pour en esquisser une nouvelle topographie, où la logique du plateau vient se superposer à l’imitation des codes socio-culturels. Ce sont ces jeux de va-et-vient entre deux systèmes concurrents de définition du genre que le présent volume se propose d’explorer