Graphe des réflexions dans les volumes complexes : construction, simplifications perceptives et auralisation

National audienceDans le cadre de recherches sur le rendu sonore dynamique d'environnements complexes, nous proposons une nouvelle méthode de classification des chemins acoustiques entre une source et un auditeur placés dans un environnement virtuel. La propagation du son à l'intérieur de cette scène est représentée à l'aide d'un graphe de réflexions. Chaque n{\oe}ud de ce graphe bidirectionnel représente une réflexion du son sur un des éléments de la scène, les extrémités du graphe représentant la source et l'auditeur. Le processus de restitution spatialisée reste à l'heure actuelle la partie la plus complexe à réaliser en temps réel ; c'est pourquoi il est essentiel de réduire le nombre de contributions, \emph{i.e.} le nombre de chemins de notre graphe. Un modèle psycho-acoustique a été créé en prenant en compte les phénomènes de masquage spatial et temporel des chemins sonores. À partir de ces données, les chemins sont agrégés en paquets nécessitant une seule opération de spatialisation, celle du chemin prédominant dans le groupe

Comparative Preclinical Study of Lidocaine and Mepivacaine in Resilient Hyaluronic Acid Fillers

Background: Hyaluronic acid-based filler injections are now well-established aesthetic procedures for the correction of skin tissue defects and volume loss. Filler injections are becoming increasingly popular, with a growing number of injections performed each year. Although classified as a minimally invasive procedure, the introduction of a needle or a canula may remain painful for the patient. A major improvement was achieved with the incorporation of local anesthetics into the formulation for pain relief. Methods: In this study, two well-known anesthetics, lidocaine and mepivacaine, were systematically compared to assess their influence on filler mechanical and biological features. The impact of each anesthetic was monitored in terms of gel rheological properties, stability, durability, and degradation. The release profiles of each anesthetic were also recorded. Finally, the pharmacokinetics of each anesthetic in rats were assessed. Results: For all the rheological and biological experiments performed, lidocaine and mepivacaine influences were comparable. The addition of either anesthetic into a soft-tissue filler showed no significant modifications of the stability, durability, and degradability of the gel, with similar release profiles and pharmacokinetics at an equivalent concentration. Conclusions: Substituting lidocaine with mepivacaine does not impact the properties of the gels, and thus both can be equally incorporated as anesthetics in soft-tissue fillers

Synthesis of Dodecavalent Fullerene‐Based Glycoclusters and Evaluation of Their Binding Properties towards a Bacterial Lectin

International audienceMultivalency is playing a major role in biological processes and particularly in lectin-carbohydrate interactions. The design of high-affinity ligands of lectins should provide molecules capable of interfering with these biological processes and potentially inhibit bacterial or viral infections. Azide-alkyne "click" chemistry was applied to the synthesis of dodecavalent fullerene-based glycoclusters. The conjugation could be efficiently performed from alkyne or azide functions on either partners (i.e. hexakis-fullerene adduct or glycoside). PA-IL is a bacterial lectin from the opportunistic pathogen Pseudomonas aeruginosa and is involved in the recognition of glycoconjugates on human tissues. The glycoclusters obtained were evaluated as ligands of PA-IL and for their potential for competing with its binding to glycosylated surfaces. The affinities measured by hemagglutination inhibition assay (HIA), enzyme-linked lectin assay (ELLA), and surface plasmon resonance (SPR) displayed a significant "glycoside cluster effect" with up to a 12 000-fold increase in binding when comparing a monovalent carbohydrate reference probe with a dodecavalent fullerene-based glycocluster, albeit with some differences depending on the analytical technique