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    131705 research outputs found

    Effectiveness of water system chemical disinfection against Pseudomonas aeruginosa infections, despite a not-so obvious connection

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    International audienceBackground: Pseudomonas aeruginosa is a well-recognized opportunistic pathogen frequently responsible for hospital-acquired infections. Acquisition routes of P. aeruginosa are both endogenous and exogenous, including transmission from portion of the hospital water system.Methods: Impact of disinfection procedures of the water system and description routes of P. aeruginosa transmission in a surgical ICU over a two-year period were investigated. Two distinct periods A and B were considered, respectively before and after the disinfection. Fourier transform infrared spectroscopy was used to compare isolates recovered from patients and tap water.Results: Overall, 21.3% tap water samples were positive but with a significantly lower rate in the period B (p< 0.01). Concomitantly, the prevalence of patients positive for P. aeruginosa decreased from 2.6% to 1% (p< 0.01), suggesting a correlation between the presence of environmental sources and patient contaminations. Results revealed that 18% of patients were involved in cross-transmission events not related with any isolate recovered from water, suggesting transmission through care practices. Conversely, only one environmental transmission event was suspected in a patient.Conclusion: Although the link between the hospital environment and patients was unclear, HCW-associated care practices could be related to contaminated point of use waters and then indirect spreading to patients

    Swot Cal/Val Campaign Based on the Swalis Airborne Sensor. Comparaison of σ0 over the Mont-Saint Michel Bay and over the Gondrexange/Stoke Ponds

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    International audienceThis paper presents the first comparisons of backscattering coefficients σ 0 between acquisitions from the SWALIS (Still WAter Low Incidence Scattering) airborne sensor and the space mission SWOT (Surface Water and Ocean Topography) over the Mont Saint-Michel (MSM) bay and over the Gondrexange and Stoke ponds. The MSM area is chosen both as a calibration/validation area for the SWOT mission and as a perfect area for analyzing the backscattering of specific sand areas

    (De)hydration Front Propagation Into Zero‐Permeability Rock

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    International audienceHydration and dehydration reactions play pivotal roles in plate tectonics and the deep water cycle, yet many facets of (de)hydration reactions remain unclear. Here, we study (de)hydration reactions where associated solid density changes are predominantly balanced by porosity changes, with solid rock deformation playing a minor role. We propose a hypothesis for three scenarios of (de)hydration front propagation and test it using one-dimensional hydro-mechanical-chemical models. Our models couple porous fluid flow, solid rock volumetric deformation, and (de)hydration reactions described by equilibrium thermodynamics. We couple our transport model with reactions through fluid pressure: the fluid pressure gradient governs porous flow and the fluid pressure magnitude controls the reaction boundary. Our model validates the hypothesized scenarios and shows that the change in solid density across the reaction boundary, from lower to higher pressure, dictates whether hydration or dehydration fronts propagate: decreasing solid density causes dehydration front propagation in the direction opposite to fluid flow while increasing solid density enables both hydration and dehydration front propagation in the same direction as fluid flow. Our models demonstrate that reactions can drive the propagation of (de)hydration fronts, characterized by sharp porosity fronts, into a viscous medium with zero porosity and permeability; such propagation is impossible without reactions, as porosity fronts become trapped. We apply our model to serpentinite dehydration reactions with positive and negative Clapeyron slopes and granulite hydration (eclogitization). We use the results of systematic numerical simulations to derive a new equation that allows estimating the transient, reaction-induced permeability of natural (de)hydration zones. Plain Language SummaryWe investigate reactions of hydration, which is the incorporation of water into a rock, and dehydration, which is the liberation of water from a rock, with simple mathematical models. These reactions are critical in understanding processes like plate tectonics, but many aspects of how hydration or dehydration fronts move through a rock are unclear. Our research focuses on reactions where changes in density are mostly balanced by changes in pore space, termed porosity, rather than the deformation of the solid rock. We developed mathematical models that combine fluid flow, rock deformation, and hydration/ dehydration reactions. We derived simple equations that predict changes in porosity during hydration and dehydration, even when the solid rock deforms simultaneously. We found that whether a rock hydrates or dehydrates depends on how its solid density changes with increasing pressure during the reaction. By systematically studying our model, we discovered that the speed of hydration and dehydration is not influenced by the interval of fluid pressure over which the reaction occurs or the relationship between porosity and permeability. We present an equation that can be used to estimate permeability from natural (de)hydration zones.</div

    Diffraction électronique ultrarapide appliquée aux transitions de phase photo-induites dans des matériaux quantiques morphologiquement adaptés

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    supervisors Philippe Rabiller and Maciej Lorenc (department of materials and light)sous la direction de Philoppe Rabiller et de Maciej Lorenc Laurent Guérin dans le département Matériaux et Lumièr

    Methodological approach to investigating spatial cognition in Arctic charr ( Salvelinus alpinus )

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    International audienceAbstract Assessing cognitive traits poses consistent methodological challenges. We describe a method for testing Arctic charr by incorporating a T‐maze into their housing, which reduced stress and improved the engagement of the tested fish in the task. We outline the phases of testing to evaluate learning efficiency and determine which orientation strategies, such as motor response versus beaconing, are prioritized by the animals. We emphasize the stress management aspects of the design, aiming to inspire other researchers tackling similar obstacles, rather than delving into the specific aspects of cognitive abilities assessment

    Pharmacokinetics and safety of daptomycin administered subcutaneously in healthy volunteers: a single-blinded randomized crossover trial

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    International audienceBackground: Daptomycin stands as a key IV antibiotic in treating MRSA infections. However, patients facing challenges with difficult venous access require alternative administration routes. This study aimed to evaluate the pharmacokinetic (PK) profile and safety of subcutaneous (SC) daptomycin.Patients and methods: In a two-period, two-treatment, single-blind crossover Phase I trial (ClinicalTrials.gov NCT04434300), participants with no medical history received daptomycin (10 mg/kg) both IV and SC in a random order, with a minimum 2 week washout period together with matched placebo (NaCl 0.9%). Blood samples collected over 24 h facilitated PK comparison. Monte Carlo simulations assessed the PTA for various dosing regimens. Adverse events were graded according to Common Terminology Criteria for Adverse Events(CTCAE) v5.0.Results: Twelve participants (aged 30.9 ± 24.4 years; 9 male,75%) were included. SC daptomycin exhibited delayed (median Tmax 0.5 h for IV versus 4 h for SC) and lower peak concentration than IV (Cmax = 132.2 ± 16.0 μg/mL for IV versus 57.3 ± 8.6 μg/mL for SC; P < 0.001). SC AUC0-24 (937.3 ± 102.5 μg·h/mL) was significantly lower (P = 0.005) than IV AUC0-24 (1056.3 ± 123.5 μg·h/mL) but was deemed bioequivalent. PTA demonstrated target AUC0-24 attainment for 100% of simulated individuals, for both 8 and 10 mg/kg/24 h SC regimens. Adverse events (AEs) related to SC daptomycin were more frequent than for SC placebo (25 versus 13, P = 0.016). No serious AEs were reported.Conclusions: Single-dose SC daptomycin infusion proved to be safe, exhibiting a bioequivalent AUC0-24 compared with the IV route. The SC route emerges as a potential and effective alternative when IV administration is not possible

    Lack of effects of polystyrene micro- and nanoplastics on activity and expression of human drug transporters

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    International audienceMicro- and nanoplastics (MPs/NPs) constitute emerging and widely-distributed environmental contaminants to which humans are highly exposed. They possibly represent a threat for human health. In order to identify cellular/molecular targets for these plastic particles, we have analysed the effects of exposure to manufactured polystyrene (PS) MPs and NPs on in vitro activity and expression of human membrane drug transporters, known to interact with chemical pollutants. PS MPs and NPs, used at various concentrations (1, 10 or 100 µg/mL), failed to inhibit efflux activities of the ATP-binding cassette (ABC) transporters P-glycoprotein, MRPs and BCRP in ABC transporter-expressing cells. Furthermore, PS particles did not impair the transport of P-glycoprotein or BCRP substrates across intestinal Caco-2 cell monolayers. Uptake activities of solute carriers (SLCs) such as OCT1 and OCT2 (handling organic cations) or OATP1B1, OATP1B3, OATP2B1, OAT1 and OAT3 (handling organic anions) were additionally not altered by PS MPs/NPs in HEK-293 cells overexpressing these SLCs. mRNA expression of ABC transporters and of the SLCs OCT1 and OATP2B1 in Caco-2 cells and human hepatic HepaRG cells were finally not impaired by a 48-h exposure to MPs/NPs. Altogether, these data indicate that human drug transporters are unlikely to be direct and univocal targets for synthetic PS MPs/NPs

    Synthetic Data: Generate Avatar Data on Demand

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    Anonymization is crucial for the sharing of personal data in a privacy-aware manner yet it is a complex task that requires to set up a trade-off between the robustness of anonymization (i.e., the privacy level provided) and the quality of the analysis that can be expected from anonymized data (i.e., the resulting utility). Synthetic data has emerged as a promising solution to overcome the limits of classical anonymization methods while achieving similar statistical properties to the original data. Avatar-based approaches are a specific type of synthetic data generation that rely on local stochastic simulation modeling to generate an avatar for each original record. While these approaches have been used in healthcare, their attack surface is not well documented and understood. In this paper, we provide an extensive assessment of such approaches and comparing them against other data synthesis methods. We also propose an improvement based on conditional sampling in the latent space, which allows synthetic data to be generated on demand (i.e., of arbitrary size). Our empirical analysis shows that avatar-generated data are subject to the same utility and privacy trade-off as other data synthesis methods with a privacy risk more important on the edge data, which correspond to records that have the fewest alter egos in the original data.</div

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    HAL-Rennes 1 is based in France
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