Collège de France

About: Collège de France is a education organization based out in Paris, France. It is known for research contribution in the topics: Population & Dopamine. The organization has 6541 authors who have published 11983 publications receiving 648742 citations. The organization is also known as: College de France.

The role of the hydrogen evolution reaction in the solid–electrolyte interphase formation mechanism for “Water-in-Salt” electrolytes

Abstract: Aqueous Li-ion batteries have long been envisioned as safe and green energy storage technology, but have never been commercially realized owing to the limited electrochemical stability window of water, which drastically hampers their energy density. Recently, Water-in-Salt electrolytes (WiSEs) in which a large amount of organic salt is dissolved into water were proposed to allow for assembling 3 V Li-ion batteries. Hereby, our attention focused on the fate of water at the electrochemical interface under negative polarization and the potential reactivity of TFSI anions with products originating from the water reduction. Hence, combining analysis of bulk electrolytes with electrochemical measurements on model electrodes and operando characterization, we were able to demonstrate that hydroxides generated during the hydrogen evolution reaction can chemically react with TFSI and catalyze the formation of a fluorinated solid–electrolyte interphase (SEI) that prevents further water reduction. Mastering this new SEI formation path with the chemical degradation of TFSI anions mediated by the electrochemical reduction of water can therefore open new avenues for the future development of not only WiSEs but also Li batteries functioning in organic electrolytes.

Effects of an Adaptive Game Intervention on Accessing Number Sense in Low-Socioeconomic-Status Kindergarten Children

Abstract: “The Number Race” is an adaptive game designed to improve number sense. We tested its effectiveness using a cross-over design in 53 low socioeconomic status kindergarteners in France. Children showed improvements in tasks traditionally used to assess number sense (numerical comparison of digits and words). However, there was no improvement on non-symbolic measures of number sense, suggesting that rather than being in number sense per se, the improvement was in number sense access; or links between symbolic and non-symbolic representations of number. Focused adaptive interventions such as this may contribute to reducing the socioeconomic gap in math achievement.

Transient pores in stretched vesicles: role of leak-out

Abstract: We have visualized macroscopic transient pores in mechanically stretched giant vesicles. They can be observed only if the vesicles are prepared in a viscous solution to slow down the leak-out of the internal liquid. We study here theoretically the full dynamics of growth (driven by surface tension) and closure (driven by line tension) of these large pores. We write two coupled equations of the time evolution of the radii r(t) of the hole and R(t) of the vesicle, which both act on the release of the membrane tension. We find four periods in the life of a transient pore: (I) exponential growth of the young pore; (II) stop of the growth at a maximum radius rm; (III) slow closure limited by the leak-out; (IV) fast closure below a critical radius, when leak-out becomes negligible. Ultimately the membrane is completely resealed. Notation d membrane thickness E surface stretching modulus K b Helfrich bending constant Q leak-out flux r pore radius r i pore radius at nucleation r c pore radius at zero tension r L characteristic radius of leak-out r m radius at maximum (II) r 23 pore radius at cross-over between (II) and (III) r 34 pore radius at cross-over between (III) and (IV) R vesicle radius R i initial vesicle radius R 0 vesicle radius at zero tension V L leak-out velocity V 3 slow closure velocity limited by leak-out (III) V 4 fast closure velocity at end (IV) η 2 lipid viscosity η s surface viscosity η 0 viscosity of solution σ surface tension σ 0 surface tension before pore opening τ rise time of pore growth (I) J line tension

The role of the eye and of the hypothalamus in the photostimulation of gonads in the duck.

Abstract: The successive phases of the photosexual reflex in birds involve the eye, the hypothalamus, the adenohypophysis and the gonads. On June 6, I reviewed structural components of the retino-hypothalamo-hypophyseal pathway in the duck (Anas platyrhynchos). Today, I shall rapidly review the successive experiments which, since thirty years, enabled me and my collaborators to ascertain the rBle of effective light radiations in this mechanism, as well as the properties of the two photoreceptors which seems to be complementarily involved in the photosexual reflex : the superficial, retinal photoreceptor, and the deep, hypothalamic photoreceptor. I. Experiments demonstrating the r6le of the eye as superficial photore-