HAL-UJM
Not a member yet
95306 research outputs found
Sort by
Optimising protamine dosing for heparin reversal after cardiopulmonary bypass: a population pharmacokinetic–pharmacodynamic study
No full textInternational audienceBackground: Protamine is administered to reverse unfractionated heparin (UFH) after cardiopulmonary bypass (CPB), but dosing strategies-typically based on protamine-to-heparin (P:H) ratios-vary, and the minimal effective dose remains unclear. Reversal is commonly assessed using activated clotting time (ACT), which may not reliably reflect residual heparin activity. We used pharmacometric modeling to determine a minimal effective P:H ratio and to characterise the anti-factor Xa (anti-Xa) activity-ACT relationship.Methods: In this prospective, single-centre study, 68 adults undergoing CPB-assisted cardiac surgery were enrolled. A total of 757 blood samples were collected intraoperatively and after UFH reversal to measure anti-Xa activity and ACT. A population pharmacokinetic-pharmacodynamic model was developed using a nonlinear mixed-effects approach to describe UFH neutralisation by protamine. This model was then used to perform Monte Carlo simulations estimating the probability of complete reversal (anti-Xa <0.10 IU ml-1) at various P:H ratios, based on cumulative intraoperative UFH dose.Results: Patients received a mean total dose of 30 250 IU UFH and 200 mg protamine i.v. Measured anti-Xa activity decreased to <0.10 IU ml-1 in all patients within 10 min of protamine initiation, indicating rapid reversal. Model-based simulations predicted that a P:H ratio of 0.625:1 would achieve complete reversal in 95% of patients. Although ACT and anti-Xa activity were positively associated, ACT values varied widely at low anti-Xa concentrations.Conclusions: A P:H ratio of 0.625:1 provided adequate UFH reversal. Given the imprecision of ACT, fixed low-ratio dosing without routine monitoring could be a practical alternative but requires prospective validation.Clinical trial registration: EudraCT (2019-000859-14); www.Clinicaltrials: gov (NCT04092868)
Dewey’s Vision of Democracy and Work
No full text"This handbook is currently in development, with individual articles publishing online in advance of print publication. "International audience"John Dewey’s vision of work is strictly related to and dependent on his wide, social view of democracy. Dewey conceived of democracy as the complex form of a society, rather than as a political regime. According to this view, for democracy to be achieved, a society must, among other things, fully democratize work and the workplace. This chapter begins by presenting Dewey’s vision of democracy, and then proceeds to articulate his democratic vision of work and the workplace. It notably shows that Dewey saw a virtuous circle between work and democracy: on the one hand, the quality of work experience is enhanced when it is carried out under democratic conditions; on the other hand, democratic work contributes to the deepening of democratic habits in individuals and to the realization of the democratic ideal throughout the entire society.
From pore collapse to crystal growth: ultrafast laser-induced stishovite formation in nanoporous silica
No full textInternational audienceThe crystallization of amorphous solids under ultrafast laser irradiation represents a paradigm of non-equilibrium phase transitions, where the interplay between electromagnetic energy localization and atomic-scale dynamics remains largely uncharted. By using a multiscale framework that couples Finite-Difference Time-Domain simulations of nonlinear light propagation with Molecular Dynamics of the atomic response, we demonstrate that field enhancement at nanopore interfaces confines laser energy and drives a rapid collapse of the surrounding matrix. In the silica structure containing a nanopore of 2 nm radius, corresponding to a porosity of approximately 7%, the enhanced local electromagnetic field led to a final equilibrium temperature 16% higher than for the 1-nm pore (1% porosity), and 20% higher than for the homogeneous medium. Particularly, the heterogeneous energy localization in the 2-nm-pore system created a preferential nucleation site within the dense glass network and led to the ultrafast formation of stishovite, a high-pressure crystalline phase of SiO2, on a sub-nanosecond timescale, significantly faster than in homogeneous silica at the same equilibrium temperature.Such accelerated crystallization enables the phase transition to outpace pressure relaxation, which would otherwise inhibit stishovite formation under identical thermal loading. These predictions align with experimental observations of laser-induced crystallization in confined geometries and establish nanopores as potent catalysts for controlling solid-state transformations via tailored electromagnetic hotspots.La cristallisation des solides amorphes sous irradiation laser ultrarapide représente un paradigme des transitions de phase hors équilibre, où l’interaction entre la localisation de l’énergie électromagnétique et la dynamique à l’échelle atomique reste largement inexplorée. En utilisant un cadre multi-échelle qui couple des simulations Finite-Difference Time-Domain de la propagation non linéaire de la lumière avec des dynamiques moléculaires de la réponse atomique, nous démontrons que l’amplification du champ aux interfaces des nanopores confine l’énergie laser et entraîne un effondrement rapide de la matrice environnante. Dans la structure de silice contenant un nanopore de rayon 2 nm, correspondant à une porosité d’environ 7%, le champ électromagnétique local amplifié a conduit à une température d’équilibre finale 16% plus élevée que pour le pore de 1 nm (1% de porosité), et 20% plus élevée que pour le milieu homogène. En particulier, la localisation hétérogène de l’énergie dans le système à pore de 2 nm a créé un site de nucléation préférentiel au sein du réseau vitreux dense et a conduit à la formation ultrarapide de la stishovite, une phase cristalline haute pression de SiO2, à l’échelle de temps sub-nanoseconde, significativement plus rapide que dans la silice homogène à la même température d’équilibre.Une telle cristallisation accélérée permet à la transition de phase de devancer la relaxation de la pression, qui inhiberait autrement la formation de stishovite sous une charge thermique identique. Ces prédictions concordent avec les observations expérimentales de cristallisation induite par laser dans des géométries confinées et établissent les nanopores comme de puissants catalyseurs pour contrôler les transformations à l’état solide via des points chauds électromagnétiques conçus sur mesure
Le contrôle des opérations de concentration sous les seuils de notification
No full textInternational audienc
Hydrogen diffusion in hydrous minerals from Raman and NanoSIMS mapping – implications for isotopic characterization of fluid–rock interactions
No full textInternational audienceHydrogen diffusion in major hydrous minerals determines the closure temperatures of isotopic exchange used to track fluid–rock interactions. Deuterium–hydrogen (D–H) exchange was experimentally investigated between minerals and deuterated gas (D2) in an ambient-pressure furnace over the temperature range of 400–650 °C (tremolite, vesuvianite) and between minerals and D2O at high pressure (1.5–3 GPa) and temperature (315–500 °C) in a belt press (glaucophane, epidote). D / (D + H) ratios in exchanged mineral grains were mapped using Raman spectroscopy calibrated by comparison with NanoSIMS analyses. Diffusion coefficients constrained by isotopic profiles were fitted to the Arrhenius equation DD/H=D0e(-Ha/RT), where Ha is the activation enthalpy, and D0 is the diffusion coefficient at infinite temperature T. The validity of intracrystalline diffusion laws from the literature is discussed with respect to the mechanical properties of hydrous minerals. Diffusion in tremolite is affected by intense cleavage, which reduces the effective grain size relative. High pressure appears to suppress cleavage opening in glaucophane. Results suggest that plasticity counteracts grain size reductions along cleavage planes in phyllosilicates. For vesuvianite, which lacks cleavage planes, intracrystalline diffusion is a valid assumption. In epidote, diffusivities are scattered over several orders of magnitude. Closure temperatures for hydrogen isotope diffusion were calculated and indicate that vesuvianite and phyllosilicates can record fluid–rock interactions under regional metamorphic conditions. Amphiboles may retain information about relatively short-lived eruptive events. Spatially resolved measurements of hydrogen isotopic compositions in those minerals may reveal low-temperature (100 < T < 400 °C) fluid–rock interactions associated with slip along major faults and metamorphic terrane exhumation
Timing pre-saccadic attention : Temporal dynamics of the Size-Eccentricity Effect’s compensation
No full textInternational audienc
Impact of Surgical Masks on Newborns' Spontaneous Face Processing Skills
No full textInternational audienceABSTRACT At birth, newborns prefer upright faces over other stimuli, indicating that they already pay specific attention to facial internal features, with expectations about their featural configuration. The study investigated whether surgical mask wearing in maternity wards due to COVID‐19 disrupts newborns' face processing. Using a visual preference paradigm, newborns saw paired images of the same face. In Condition 1, both faces were upright, one masked, one unmasked. No preference was found. In Condition 2, newborns saw an upright masked face versus the same masked face but inverted (i.e., upside down), showing a preference for the upright version. Findings suggest that masked and unmasked static faces equally attract newborns' attention and that surgical masks do not disrupt their face configuration processing. It has implications for recommendations to the general public, especially individuals in contact with newborns
Transfer of generalized amalgamation in simple theories
No full textWe give an abstract framework to transfer generalized amalgamation from a simple theory to another, and we apply it to theories of lovely pairs and of bounded PAC structures. We show in particular that bounded pseudo-algebraically closed fields have generalized amalgamation, regardless of their imperfection degree