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

Photo-induced Energy Transfer in a Th-Symmetrical Hexakis-adduct of C60 Substituted with π-Conjugated Oligomers

International audienceA stilbene derivative bearing a terminal alkyne unit has been prepared and grafted onto a Th‐symmetrical C60 hexakis‐adduct building block under alkyne/azide copper mediated Huisgen 1,3‐dipolar cycloaddition conditions. The photophysical properties of the resulting fullerene derivative surrounded by 12 conjugated oligomers have been investigated. Upon excitation of the peripheral chromophores, an efficient intramolecular energy transfer to the C60 core has been evidenced

Uncoupling programmed DNA cleavage and repair scrambles the Paramecium somatic genome

Summary: In the ciliate Paramecium, precise excision of numerous internal eliminated sequences (IESs) from the somatic genome is essential at each sexual cycle. DNA double-strands breaks (DSBs) introduced by the PiggyMac endonuclease are repaired in a highly concerted manner by the non-homologous end joining (NHEJ) pathway, illustrated by complete inhibition of DNA cleavage when Ku70/80 proteins are missing. We show that expression of a DNA-binding-deficient Ku70 mutant (Ku70-6E) permits DNA cleavage but leads to the accumulation of unrepaired DSBs. We uncoupled DNA cleavage and repair by co-expressing wild-type and mutant Ku70. High-throughput sequencing of the developing macronucleus genome in these conditions identifies the presence of extremities healed by de novo telomere addition and numerous translocations between IES-flanking sequences. Coupling the two steps of IES excision ensures that both extremities are held together throughout the process, suggesting that DSB repair proteins are essential for assembly of a synaptic precleavage complex