64 research outputs found

    Functional and Morphological Studies of Mitochondria Exposed to Undecagold Clusters: Biologic Surfaces Labeling with Gold Clusters

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    This study reports morphological and functional alterations observed in respiring isolated mitochondria when they are exposed to nonpenetrating, positive electrostatically charged synthetic undecagold clusters. Modification of the undecagold clusters positive charges change or prevent the functional effects and the binding to the outside surface of the mitochondria. The mitochondrial functional alterations are dependent on the oxidative phosphorylation capacity of the isolated organelles. The results of these experiments indicate that artificial undecagold may be useful to explore the molecular mechanisms of biological energy transducers which require electric charges separation, ionic fluxes, and electric surface properties

    Properties of Photogenerated Tryptophan and Tyrosyl Radicals in Structurally Characterized Proteins Containing Rhenium(I) Tricarbonyl Diimines

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    Aromatic amino acid radicals are key intermediates in nucleic acid biosynthesis, DNA repair, dioxygen reduction by cytochrome oxidase, water oxidation by PSII, as well as other biological procesess. In our work on electron tunneling in proteins, we have developed laser flash/quench methods that potentially could facilitate the study of such highly reactive radicals. To test our methods, we are investigating two structurally characterized proteins, [Re(CO)_3(L)(H83)]^+AzM^(2+) and [Re(CO)_3(L)(H107)]^+AzM^(2+) (L ) 1,10-phenanthroline (phen) or 4,7-Me_2phen; Az ) Pseudomonas aeruginosa azurin; M ) Cu or Zn). Of special interest is that calculations and experiments on the H107 protein show that Cu^+ oxidation via electron transfer (ET) through an intervening tyrosine (Cu^+ → Y108^(./) → Re(2+)) is over 2 orders of magnitude faster than optimized (Cu^+ → Re^(2+)) electron tunneling

    Fusion multimodale pour les systèmes d interaction

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    Les chercheurs en informatique et en génie informatique consacrent une partie importante de leurs efforts sur la communication et l'interaction entre l'homme et la machine. En effet, avec l'avènement du traitement multimodal et du multimédia en temps réel, l'ordinateur n'est plus considéré seulement comme un outil de calcul, mais comme une machine de traitement, de communication, de collection et de contrôle, une machine qui accompagne, aide et favorise de nombreuses activités dans la vie quotidienne. Notre projet de recherche permettra une meilleure compréhension de la fusion et de l'interaction multimodale, par la construction d'un moteur de fusion en utilisant des technologies de Web sémantique. L'objectif est de développer un système expert pour l'interaction multimodale personne-machine qui mènera à la conception d'un outil de surveillance pour personnes âgées, afin de leurs assurer une aide et une confiance en soi, à domicile comme à l'extérieur.Researchers in computer science and computer engineering devote now a significant part of their efforts in communication and interaction between human and machine. Indeed, with the advent of real-time multimodal and multimedia processing, computer is no longer seen only as a calculation tool, but as a machine of communication processing, collection and control, a machine that accompanies, assists or promotes many activities in daily life. This research will allow a better understanding of the multimodal fusion and interaction, by the construction of a fusion engine using technologies of semantic web domain. The aim is to develop an expert system for multimodal human-machine interaction that will lead to design a monitoring tool for seniors and handicaps to ensure their support and confidence, at home or outside.VERSAILLES-BU Sciences et IUT (786462101) / SudocSudocFranceCanadaFRC

    Solid polymer electrolytes from a fluorinated copolymer bearing cyclic carbonate pendant groups

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    A poly(vinylidene fluoride-co-(2-oxo-1,3-dioxolan-4-yl)methyl 2-(trifluoromethyl)acrylate) random copolymer, poly(VDF-co-MAF-cyCB), with a MAF-cyCB weight fraction of 59% was synthesized via free radical copolymerization of VDF and MAF-cyCB, which is a methacrylate bearing cyclocarbonate side-chain. This copolymer showed nano-structured morphology, where crystalline PVDF-rich domains co-existed with amorphous poly(VDF-co-MAF-cyCB) segments. Solid polymer electrolytes were further obtained by loading the poly(VDF-co-MAF-cyCB) copolymer with various amounts of LiClO4. The added lithium salt was dissolved in the poly(VDF-co-MAF-cyCB) amorphous phase, which allowed the formation of an ionic conducting phase exhibiting ionic conductivity values as high as 2 × 10−4 S cm−1 at room temperature for an optimum cyCB/Li+ molar ratio of 5. The addition of LiClO4 up to the optimum cyCB/Li+ molar ratio of 5 also increased the phase separation between the crystalline and amorphous phases, the mechanical properties of the material (up to 107 at 102 rad s−1) and the ionic conductivity (>10−3 S cm−1 at 80 °C). Furthermore, an electrochemical stability window from 1.4 to 4.9 V vs. Li/Li+ and relatively high values for the measured lithium ions transference numbers (0.68 at 40 °C) were observed, making the investigated system a promising candidate for next generation solid polymer electrolytes

    Interdisciplinary research in artificial intelligence: challenges and opportunities

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    The use of artificial intelligence (AI) in a variety of research fields is speeding up multiple digital revolutions, from shifting paradigms in healthcare, precision medicine and wearable sensing, to public services and education offered to the masses around the world, to future cities made optimally efficient by autonomous driving. When a revolution happens, the consequences are not obvious straight away, and to date, there is no uniformly adapted framework to guide AI research to ensure a sustainable societal transition. To answer this need, here we analyze three key challenges to interdisciplinary AI research, and deliver three broad conclusions: 1) future development of AI should not only impact other scientific domains but should also take inspiration and benefit from other fields of science, 2) AI research must be accompanied by decision explainability, dataset bias transparency as well as development of evaluation methodologies and creation of regulatory agencies to ensure responsibility, and 3) AI education should receive more attention, efforts and innovation from the educational and scientific communities. Our analysis is of interest not only to AI practitioners but also to other researchers and the general public as it offers ways to guide the emerging collaborations and interactions toward the most fruitful outcomes
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