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Active learning algorithm through the lens of rejection arguments
No full textActive learning is a paradigm of machine learning which aims at reducing the amount of labeled data needed to train a classifier. Its overall principle is to sequentially select the most informative data points, which amounts to determining the uncertainty of regions of the input space. The main challenge lies in building a procedure that is computationally efficient and that offers appealing theoretical properties; most of the current methods satisfy only one or the other. In this paper, we use the classification with rejection in a novel way to estimate the uncertain regions. We provide an active learning algorithm and prove its theoretical benefits under classical assumptions. In addition to the theoretical results, numerical experiments have been carried out on synthetic and non-synthetic datasets. These experiments provide empirical evidence that the use of rejection arguments in our active learning algorithm is beneficial and allows good performance in various statistical situations
Exploring the spectral optical properties of soot aerosols and the impact of ageing: a mechanistic study in the large CESAM simulation chamber
No full textInternational audienc
Impaired Pharmacokinetics of Amiodarone under Veno-Venous Extracorporeal Membrane Oxygenation: From Bench to Bedside
No full textInternational audienceBackground: Adjusting drug therapy under veno-venous extracorporeal membrane oxygenation (VV ECMO) is challenging. Although impaired pharmacokinetics (PK) under VV ECMO have been reported for sedative drugs and antibiotics, data about amiodarone are lacking. We evaluated the pharmacokinetics of amiodarone under VV ECMO both in vitro and in vivo.Methods: In vitro: Amiodarone concentration decays were compared between closed-loop ECMO and control stirring containers over a 24 h period. In vivo: Potassium-induced cardiac arrest in 10 pigs with ARDS, assigned to either control or VV ECMO groups, was treated with 300 mg amiodarone injection under continuous cardiopulmonary resuscitation. Pharmacokinetic parameters Cmax, Tmax AUC and F were determined from both direct amiodarone plasma concentrations observation and non-linear mixed effects modeling estimation.Results: An in vitro study revealed a rapid and significant decrease in amiodarone concentrations in the closed-loop ECMO circuitry whereas it remained stable in control experiment. In vivo study revealed a 32% decrease in the AUC and a significant 42% drop of Cmax in the VV ECMO group as compared to controls. No difference in Tmax was observed. VV ECMO significantly modified both central distribution volume and amiodarone clearance. Monte Carlo simulations predicted that a 600 mg bolus of amiodarone under VV ECMO would achieve the amiodarone bioavailability observed in the control group.Conclusions: This is the first study to report decreased amiodarone bioavailability under VV ECMO. Higher doses of amiodarone should be considered for effective amiodarone exposure under VV ECMO
The respiratory microbiota alpha-diversity in chronic lung diseases: first systematic review and meta-analysis
No full textInternational audienceBackground While there seems to be a consensus that a decrease in gut microbiome diversity is related to a decline in health status, the associations between respiratory microbiome diversity and chronic lung disease remain a matter of debate. We provide a systematic review and meta-analysis of studies examining lung microbiota alpha-diversity in patients with asthma, chronic obstructive pulmonary disease (COPD), cystic fibrosis (CF) or bronchiectasis (NCFB), in which a control group based on disease status or healthy subjects is provided for comparison. Results We reviewed 351 articles on title and abstract, of which 27 met our inclusion criteria for systematic review. Data from 24 of these studies were used in the meta-analysis. We observed a trend that CF patients have a less diverse respiratory microbiota than healthy individuals. However, substantial heterogeneity was present and detailed using random-effects models, which limits the comparison between studies. Conclusions Knowledge on respiratory microbiota is under construction, and for the moment, it seems that alpha-diversity measurements are not enough documented to fully understand the link between microbiota and health, excepted in CF context which represents the most studied chronic respiratory disease with consistent published data to link alpha-diversity and lung function. Whether differences in respiratory microbiota profiles have an impact on chronic respiratory disease symptoms and/or evolution deserves further exploration
Front-Tracking approaches for the modelling of breakup and coalescence
No full textInternational audienc
Les multiples effets de l'intégration des technologies de l'information et de la communication (TIC) sur les pratiques coopératives en santé. Le cas de la télémédecine
No full textInternational audienc
Influence of self-substitution on the thermoelectric Fe2VAl Heusler alloy
No full textInternational audienceThe microstructure and the thermoelectric properties were systematically determined in the Fe2V1+xAl1-x, Fe2+xVAl1-x, Fe2-xV1+xAl series to investigate the influence of self-substitution on the Fe2VAl Heusler alloy. In the explored range of compositions (−0.1 < x < 0.1), all these series are solid solutions, which form anti-site defects to accommodate the off stoichiometry. They all crystallize in the cubic L21 structure, but their lattice parameter unusually increases with lxl. A Bader analysis based on Density Functional Theory calculations indicates that these uncommon lattice parameter changes arise from variations in the interatomic electron transfer. The antisite defects behave like dopants that control the conduction type and charge carrier concentration. This leads to large thermoelectric power factor (PF) in the Fe2V1+xAl1-x series, which displays the largest electronic mobility. PF = 6.7 mW m−1 K−2 at 250 K and PF = 3.2 mW m−1 K−2 at 325 K are reached in n-type Fe2V1.03Al0.97 and p-type Fe2V0.985Al1.015 respectively. The lattice thermal conductivity systematically decreases upon self-substitution, but with differences among the series which can be traced back to the interatomic electron transfer unveiled by the Bader analysis. Finally, the figure of merit is improved to ZT = 0.06 at 500 K in p-type Fe2V0.93Al1.07 and ZT = 0.15 at 420 K in n-type Fe2V1.08Al0.92
Absence of Mortality Differences Between the First and Second COVID-19 Waves in Kidney Transplant Recipients
No full textInternational audienceSARS-CoV-2 pandemic evolved in two consecutive waves over 2020. Improvements in the management of COVID-19 led to a reduction of mortality rates in hospitalized patients during the second wave. Whether this progress also benefited to kidney transplant recipients (KTR), a population particularly vulnerable to severe COVID-19, remained unclear. In France, 957 KTR were hospitalized for COVID-19 in 2020 and their data were prospectively collected in the French SOT COVID registry. The presentation, management, and outcomes of the 359 KTR diagnosed during the 1st wave were compared to those of the 598 of the 2nd wave. Baseline comorbidities were similar between KTR of the 2 waves. Maintenance immunosuppression was reduced in most patients but withdrawal of antimetabolite (73.7% vs 58.4%, p<0.001) or CNI (32.1% vs 16.6%, p<0.001) was less frequent during the 2nd wave. Hydroxychloroquine and azithromycin that were commonly used during the 1st wave (21.7% and 30.9%, respectively) were almost abandoned during the 2nd. In contrast, the use of high dose corticosteroids doubled (19.5% vs. 41.6%, p<0.001). Despite these changing trends in COVID-19 management, 60-day mortality was not statistically different between the 2 waves (25.3% vs. 23.9%; Log Rank, p=0.48) and COVID-19 hospitalization period was not associated with death due to COVID in multivariate analysis (HR 0.89, 95% CI 0.67 - 1.17, p = 0.4). We conclude that changing of therapeutic trends during 2020 did not reduce COVID-19 related mortality in KTR. Our data indirectly support the importance of vaccination and monoclonal neutralizing anti-SARS-CoV-2 antibodies to protect KTR from severe COVID-19
