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Maximum cold ischemia duration for a kidney allograft: a prediction model for allograft failure at the time of organ allocation
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Pharmacokinetic Prediction and Cytotoxicity of New Quercetin Derivatives
No full textInternational audienceQuercetin (QUE) possesses various pharmacological properties; however, its low bioavailability and solubility hinder its beneficial effects. Enzymatic glycosylation has been explored to improve these aspects. In the present study, we used a sucrose phosphorylase variant to catalyze the regioselective transglucosylation of QUE, predicted the pharmacokinetic properties and toxicity of these molecules using in silico tools, and evaluated their cytotoxicity compared to the original molecule and a β‐glucosylated derivative of QUE. Three α‐glucosylated derivatives were obtained, which demonstrated improved pharmacokinetics, including a higher volume of distribution and lower clearance rate, with minimal likelihood of cytochrome P450 enzyme inhibition compared to QUE. QUE and the β‐glucosylated derivative exhibited cytotoxicity in both cell types evaluated, whereas their α‐glucosylated derivatives were nontoxic. The results presented provide an insight into the predicted behavior of these molecules in the body and, combined with cytotoxicity evaluation, will serve as a foundation for investigating the biological effects and mechanisms of action of these new molecules
Wave scattering from graphene-covered circular dielectric wire collections analysed using the single-wire part inversion: diffraction radiation case
No full textInternational audienceWe consider infrared (IR)-range diffraction radiation (DR) from finite configurations of circular graphene-covered dielectric nanowires excited by the density-modulated beam of charged particles. The beam velocity is assumed constant, and its field in the free space is considered as the incident one. The characterization of graphene employs the quantum-theory Kubo formalism and the resistive-sheet boundary conditions involving the frequency-dependent graphene surface impedance. To transform the problem into a well-conditioned algebraic equation for the field expansion coefficients, we use the separation of variables in the local coordinates and the addition theorem for the cylindrical functions. This leads to explicit inversion of the single-wire part of the problem, i.e. to the regularization, provides easy control of the accuracy and enables us to study fine resonance effects associated with the natural modes of the wire collections as open resonators.This article is part of the theme issue 'Analytically grounded full-wave methods for advances in computational electromagnetics'
Applying machine learning to anticipate crisis management of marine submersion events
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von Willebrand Factor Substitution for Neuraxial Anaesthesia in Women With Persistent von Willebrand Deficiency at Term of Pregnancy
No full textInternational audienceIntroduction: Most von Willebrand factor (VWF) deficiencies are spontaneously corrected at the end of pregnancy, allowing neuraxial anaesthesia (NA) if VW:Act and FVIII levels are higher than 50% (ISTH recommendations). When VWF:Act and WEI are not spontaneously corrected at the end of pregnancy, the risk of bleeding during and after delivery is covered by the infusion of VWF (±FVIII) concentrates. We aim to evaluate the safety of NA performed in this context, by reporting those cases and describing doses and monitoring procedures.Methods: We performed a retrospective review (between 2008 and 2022) of the medical records of 44 patients from 8 different French hospitals. Inclusion criteria were: women with, (1) VWF deficiency not spontaneously corrected at the end of pregnancy, (2) who received VWF (±FVIII) infusions at delivery and (3) who benefited from NA. A total of 91 pregnancies were reviewed. Out of those 91, 52 met all criteria for inclusion.Results: At the end of the 52 pregnancies, although the mean FWD level was 91%, [11%-250%], the VWF:Act levels were much lower, with a mean value of 36% [6%-76]. All had VWF.Act levels were <51% excepting one (a VWF Type 2N with VWF:Act = 76% and FVIII = 26%). The mean platelet count was of 246 g/L [133-394 g/L] and mean fibrinogen level was 4.5 g/L [3.1-6.2 g/L]. At the time of NA, 44 patients received VWF concentrates and 8 received VWF+FVIII concentrates. The doses of VWF concentrates for the first infusion ranged from 16 to 66 UI/kg, with a mean value of 465 UI/kg.Depending on the centre, VWF:Act dosages were realised before and/or after the first infusion and then every 12 or 24h, generally until the third post-partum day. The mean VWF:Act residual level was 97% [26%-247%]. The 10th-90th percentiles of the VWF:Act residual values were 45%-160%. In 40% of the cases, there was also a use of tranexamic acid. No spinal subdural hematoma nor bruise lesion were described in any patient.Discussion/Conclusion: Our study tends to show that correcting VWF:Act by infusion of VWF±FVIII concentrates could ensure a safe NA, as far as this treatment is closely monitored. In our study, reaching residual levels of VWF:Act between 46% and 160% has been efficient to prevent the haemorrhagic risk related to NA, although healthy pregnant women at delivery generally have levels exceeding 150%, Disclosure of Interest: None declared
Optimality Conditions for Multivariate Chebyshev Approximation: A Survey
No full textUniform polynomial approximation, also called minimax approximation or Chebyshev approximation, consists in searching polynomial approximation that minimizes the worst case error. Optimality conditions for the uniform approximation of univariate functions defined in an interval are governed by the equioscillation theorem, which is also a key ingredient in algorithms for computing best uniform approximation, like Remez's algorithm and the two phase method. Multivariate polynomial approximation is more complicated, and several optimality conditions for uniform multivariate polynomial approximation generalize the equioscillation theorem. We review these conditions, including, from oldest to newest, Kirchberger's kernel condition, Kolmogorov criteria, Rivlin and Shapiro's annihilating measures. An emphasis is given to conditions for strong optimality, which has some strong theoretical and practical importance, including Bartelt's and Smarzewsky's conditions. Optimality conditions related to more general relative Chebyshev centers are also presented, including Tanimoto's and Levis et al.'s conditions. In a second step, conditions obtained by standard convex analysis, subdifferential and directional derivative, applied to uniform approximation are formulated. Their relationship to previous conditions is investigated, providing sometimes enlightening interpretations of the laters, e.g., relating Kolmogorov criterion with directional derivative, and strong uniqueness with sharp minimizers. Finally, numerical applications of the two-step approach to three uniform approximation problems are presented, namely the approximation of the multidimensional Runge function, the approximation of the two dimensional inverse model of the DexTAR parallel robot, and the approximation problem consisting in minimizing the sum of both the polynomial approximation error and the polynomial evaluation error in Horner form
Methods for Defining Climate Change Mitigation Strategies at Organisational Level Review and Outlook
No full textInternational audienceThe private sector has a pivotal role in contributing to the objective of the Paris Agreement and its 1.5° target. However, there is a lack of a comprehensive framework to define and implement climate change mitigation strategies in organisations. The current study aims to fill this gap by performing a critical review of existing schemes that can make a partial contribution to the definition of such strategies. We found 25 schemes used by private sector or studied in the literature by international NGOs and academic searcher and evaluated them based on 15 criteria developed for this study in order to cover key components of an effective framework for CCMS in organisations. No scheme fulfils all the criteria, but significant differences are observed between them, ranging from 0% to 80% of the criteria met. Based on this analysis, we propose a first harmonized five-step iterative framework to define organisational climate change mitigation strategies. Eventually, the results of the schemes review and the framework proposal draw up a research agenda to derive robust, credible and operational climate strategies at organizational levels
Fuzzy Logic-Based Maximum Power Point Tracking Control for Photovoltaic Systems : A Review and Experimental Applications
No full textInternational audienceMaximum power point tracking (MPPT) is an essential technique used to extract the maximum power from a photovoltaic (PV) system. Fuzzy logic-based control is one of the popular methods used for MPPT because it provides excellent performance under varying environmental conditions. The world is now facing a challenge in terms of energy. Solar energy is a key to solve that issue, so it must be optimized. Among the MPPT optimization methods used to improve the photovoltaic modules efficiency, fuzzy logic control (FLC) seems to be the one that is really adapted. However, it has a lot of drawbacks like the complexity of implementation and its performance depends not only on the chosen error, but also on the established inference rules. To solve these problems this method has been modified in various ways. The present work makes a diversified review of MPPT algorithms using fuzzy logic control for PV applications. It is subdivided into three main parts. The first part deals with modified FLC algorithms. The second part deals with FLC algorithms associated with other classical algorithms and the third with MPPT algorithms associated with intelligent methods. The different works analyzed have tested their innovative approaches by simulation and have for the most part validated them by an. It can be noted that the third category is the one that offers a better increase in efficiency even if it has a higher complexity. The second category is more suitable for variable weather conditions and the first one is recommended especially for its very low cost. The suggested asymmetrical fuzzy logic-based MPPT technique uses an asymmetric membership function and a rule-based controller to improve the tracking accuracy and speed. The performance of the suggested technique was evaluated and compared with two existing MPPT techniques. The evaluation was conducted through simulations with MATLAB/Simulink. Overall, the results suggest that the proposed asymmetrical fuzzy logic-based MPPT technique is a promising approach for improving the speed and tracking accuracy MPPT in photovoltaic systems
Does a counterforce brace reduce common extensor tendon loading during a wrist extension task? An in vivo study
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Understanding the Role of Oxygen Substitution in Lithium Conduction and Air/Interfacial Stability of LGPS-Structured Oxy-Sulfide Electrolytes
No full textInternational audienceThe development of stable and high-performance solid electrolytes is critical for the commercialization of solid-state batteries (SSBs). This study explores materials with the composition Li9.6P3S12-kOk (0 ≤ k ≤ 1.0) by partially substituting sulfur with oxygen in Li9.6P3S12 to enhance electrochemical and ambient stability while maintaining high ionic conductivity. The synthesized compounds Li9.6P3S11.1O0.9 Li9.6P3S10.5O1.5, and Li9.6P3S9.9O2.1 having 7.5%, 12.5% and 17.5% oxygen content, named as LPSO-7.5, LPSO-12.5, and LPSO-17.5, exhibit an LGPStype structure with reduced secondary phases compared to previous studies. The highest ionic conductivity of 0.75 mS cm -1 was observed for LPSO-7.5 at 510 MPa, while increased oxygen content led to lower conductivity due to structural distortions and reduced lithium-ion mobility.Electrochemical impedance spectroscopy (EIS) and symmetric Li/SE/Li cells confirmed improved electrochemical performance with lithium metal for LPSO-7.5. Full-cell tests with LiNi0.8Co0.15Al0.05O2 (NCA) cathode and graphite or lithium anodes showed that LPSO-7.5 demonstrated the highest capacity retention and the lowest polarization. Additionally, H2S gas evolution tests confirmed improved air stability with increasing oxygen content. The results indicate that moderate oxygen substitution optimally balances conductivity, air stability and interfacial compatibility. LPSO-7.5 emerges as a promising solid electrolyte candidate for nextgeneration SSBs with enhanced cycle life and reduced degradation.</p