Two dimensional dipolar coupling in monolayers of silver and gold nanoparticles on a dielectric substrate

The dimensionality of assembled nanoparticles plays an important role in their optical and magnetic properties, via dipolar effects and the interaction with their environment. In this work we develop a methodology for distinguishing between two (2D) and three (3D) dimensional collective interactions on the surface plasmon resonance of assembled metal nanoparticles. Towards that goal, we elaborate different sets of Au and Ag nanoparticles as suspensions, random 3D arrangements and well organized 2D arrays. Then we model their scattering cross-section using effective field methods in dimension n, including interparticle as well as particle-substrate dipolar interactions. For this modelling, two effective field medium approaches are employed, taking into account the filling factors of the assemblies. Our results are important for realizing photonic amplifier devices

Effect of angiotensin-converting enzyme inhibitor and angiotensin receptor blocker initiation on organ support-free days in patients hospitalized with COVID-19

IMPORTANCE Overactivation of the renin-angiotensin system (RAS) may contribute to poor clinical outcomes in patients with COVID-19. Objective To determine whether angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB) initiation improves outcomes in patients hospitalized for COVID-19. DESIGN, SETTING, AND PARTICIPANTS In an ongoing, adaptive platform randomized clinical trial, 721 critically ill and 58 non–critically ill hospitalized adults were randomized to receive an RAS inhibitor or control between March 16, 2021, and February 25, 2022, at 69 sites in 7 countries (final follow-up on June 1, 2022). INTERVENTIONS Patients were randomized to receive open-label initiation of an ACE inhibitor (n = 257), ARB (n = 248), ARB in combination with DMX-200 (a chemokine receptor-2 inhibitor; n = 10), or no RAS inhibitor (control; n = 264) for up to 10 days. MAIN OUTCOMES AND MEASURES The primary outcome was organ support–free days, a composite of hospital survival and days alive without cardiovascular or respiratory organ support through 21 days. The primary analysis was a bayesian cumulative logistic model. Odds ratios (ORs) greater than 1 represent improved outcomes. RESULTS On February 25, 2022, enrollment was discontinued due to safety concerns. Among 679 critically ill patients with available primary outcome data, the median age was 56 years and 239 participants (35.2%) were women. Median (IQR) organ support–free days among critically ill patients was 10 (–1 to 16) in the ACE inhibitor group (n = 231), 8 (–1 to 17) in the ARB group (n = 217), and 12 (0 to 17) in the control group (n = 231) (median adjusted odds ratios of 0.77 [95% bayesian credible interval, 0.58-1.06] for improvement for ACE inhibitor and 0.76 [95% credible interval, 0.56-1.05] for ARB compared with control). The posterior probabilities that ACE inhibitors and ARBs worsened organ support–free days compared with control were 94.9% and 95.4%, respectively. Hospital survival occurred in 166 of 231 critically ill participants (71.9%) in the ACE inhibitor group, 152 of 217 (70.0%) in the ARB group, and 182 of 231 (78.8%) in the control group (posterior probabilities that ACE inhibitor and ARB worsened hospital survival compared with control were 95.3% and 98.1%, respectively). CONCLUSIONS AND RELEVANCE In this trial, among critically ill adults with COVID-19, initiation of an ACE inhibitor or ARB did not improve, and likely worsened, clinical outcomes. TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT0273570

Statuts sociométriques et perception des pairs à la maternelle.

Behavioral perception of wasstudied in relation to the social status (popular, rejected or intermediate) during the second semester of kindergarden (six year olds). It shows that rejected are perceived as having many negative behaviors, such as abandon a fight or bother other children. On the other hand populars are considered by their peers as having fex negative behaviors, being rather respectful of the class rules and helping to respect them, for instance by stopping flights. As opposed to the results of a previous study conducted with the same children during the first semester, children with an intermediate status are not different from the rejected : this might indicate that intermediate children move gradually towards a more negative status. Since boys are more negatively perceived than girls, the author suggests that rejected boys and girls as well as intermediate boys be considered with special attention in kindergarden.Une étude des perceptions comportementales des pairs (n = 66, 33 garçons et 33 filles) concernant les populaires, les moyens et les rejetés, est menée au deuxième semestre de fréquentation de la maternelle (6 ans). Elle révèle que les rejetés sont perçus par leurs pairs comme ceux et celles émettant beaucoup de comportements négatifs tels partir des batailles ou déranger les autres, alors que les populaires, aux yeux des pairs, émettent peu de comportements négatifs, respectant plutôt les règles de la classe et y contribuant en arrêtant, par exemple, les batailles. Contrairement aux résultats d'une étude antérieure menée auprès des mêmes enfants au premier semestre, les enfants de statut moyen ne se distinguent pas des rejetés dans cette étude, ce qui pourrait laisser croire qu'ils évoluent graduellement vers un statut plus négatif. Les garçons étant perçus plus négativement que les filles, l'auteur propose l'intervention dès la maternelle auprès des rejetés des deux sexes de même qu'auprès des garçons identifiés comme moyens.Begin Guy. Statuts sociométriques et perception des pairs à la maternelle.. In: Enfance, tome 39, n°4, 1986. pp. 431-444

La cohérence des désignations sociométriques à la pré-maternelle et maternelle

Boivin Michel, Bégin Guy. La cohérence des désignations sociométriques à la pré-maternelle et maternelle. In: Bulletin de psychologie, tome 40 n°380, 1987. pp. 561-569

Codage et decodage sequentiel de codes convolutionnels perfores

Dans cet article on présente le codage et le décodage séquentiel des codes convolutionnels perforés de taux de codage R=b/V. Ces codes de taux élevés sont facilement construits par élimination périodique de certains symboles codés à la sortie d'un codeur convolutionnel de taux R=1/Vo. Par rapport aux codes traditionnels de même taux et de même mémoire, ces codes offrent de grands avantages des points de vue codage et décodage sans dégradation marquée des performances d'erreur

La technique de la réponse aléatoire : un moyen de contrôler la désirabilité sociale dans la mesure de l'estime de soi

Bégin Guy, Savard France. La technique de la réponse aléatoire : un moyen de contrôler la désirabilité sociale dans la mesure de l'estime de soi. In: Bulletin de psychologie, tome 33 n°343, 1979. pp. 121-126

ROLE OF THE GRAPHITE-FeCl3 COMPOUND DURING THE PYROLYSIS OF A COAL TAR PITCH

The synthesis of a new kind of adsorbent has been carried out, using an original method. Green cokes were elaborated from the pyrolysis of a coal tar pitch mixed with first stage FeCb-graphite intercalation compounds (GIC). Carbonaceous materials with adsorbent properties can be obtained after activation of these green-cokes. The influence of the GIC during the pyrolysis of mixtures of coal tar pitch-GIC has been studied : the presence of the Lewis acid (FeCb), because of its catalytic effect, leads to an increase in the green-coke yield. Thermal stability of the first stage GIC (which can be approximately formulated : CvFeCb) under the same heat treatement conditions has been followed : the most significant desorption of FeCb takes place in the same temperature range as that of the transformation of coal tar pitch into green-coke. Study of the mesophase (intermediate phase between coal tar pitch and green-coke) shows the catalytic effect of the GIC during this step. Finally, the adsorbing properties of the activated green cokes have been studied with gases such as H2SNous décrivons dans cet article la synthèse d'une nouvelle variété de charbon actif en employant une méthode nouvelle et originale. En effet, la copyrolyse de brai de houille et de composé d'insertion du graphite (graphite- FeCb (GIC)) doit permettre d'élaborer des semi-cokes chargés qui après activation conduisent à des matériaux aux propriétés adsorbantes sélectives. Nous avons étudié le rôle du GIC lors de la pyrolyse des mélanges brai-GIC : la nette augmentation du rendement en semi-coke traduit l'activité catalytique de l'acide de Lewis FeCb qui se désorbe des particules de GIC au cours de la pyrolyse. L'étude de la stabilité thermique du GIC (de formule C7FeCl3) a montré que la désorption de FeCb s'effectue principalement entre 350 et 500°C, domaine de température au cours duquel le brai se transforme en semi-coke. Une étude détaillée de la mésophase (phase intermédiaire entre le brai et le semi-coke) a mis en évidence le rôle catalytique du GIC lors de cette transformation. Enfin, les premiers essais quant au pouvoir adsorbant des semi-cokes activés sont prometteurs vis à vis de l'adsorption d'espèces gazeuses soufrées comme H2

Nanocomposite Polymer Scaffolds Responding under External Stimuli for Drug Delivery and Tissue Engineering Applications

International audienc