DOSAGE DES ALCALINS À LA SURFACE DES VERRES SILICATÉS

Les verres binaires : Na2O - SiO2, K2O - SiO2 et ternaires : Na2O ou K2O - CaO - MgO - SiO2 ont été fracturés sous ultravide afin d'effectuer l'analyse Auger de surfaces vierges de verres de compositions bien définies. Le dosage des ions Na+, K+ et Ca2+ des surfaces de fracture a été rapporté aux compositions massiques des verres. Les résultats ont mis en évidence que les variations des hauteurs des pics Auger des cations au cours de chaque mesure dépendaient à la fois de la nature du cation, de la composition du verre et de la densité du faisceau primaire d'électrons. L'interprétation montre que ces variations sont dues à l a migration des cations à l'intérieur de l'échantillon sous l'influence d'un champ électrique qui peut être calculé à l'aide d'un modèle théorique.The binary glasses (Na2O - SiO2, K2O - SiO2) and the ternary glasses (Na2O or K2O - CaO - MgO - SiO2) have been fractured under ultra high vacuum conditions before the Auger analysis of the freshly-created surfaces. The Na+, K+ and Ca2+ Auger signals have been reported against the bulk concentrations of the cations. The results have shown that the heights of the Auger peaks strongly varied during the electron bombardment depending on the glass composition and the electron beam density. This phenomenon is related to the migration of the cations due to an electric field. The characteristics of this field can be described by a theoretical model

Optimum and Rapid Annealing of Nanocrystalline Fe73.5_{73.5}Cu1_{1}Nb3_{3}Six_{x}B(22.5−x)_{(22.5-x)} Ferromagnets-Correlation Between Magnetic, Mechanic and Thermal Analysis

In this paper we discuss the optimal and rapid treatment of Fe$_{73.5}$Cu$_{1}$Nb$_{3}$Si$_{x}$B$_{22.5-x}$ nanocrystalline alloy. In order to define an optimisation parameter of the coupled temperature/annealing time, several treatments of two alloys ($x=13.5$% and $x=15.5$%) have been studied. A rapid annealing (630 $^{\circ}$C with no step) which gives rise to better magnetic properties is proposed. It is shown that the alloy containing 15.5% of silicon is mechanically stronger when rapidly treated. Finally, it is attempted to correlate magnetic, mechanical and thermal analysis showing also how this can help to gain insight into magneto-mechanical coupling through amorphous and crystalline phase.Dans ce travail on étudie les traitements thermiques optimaux et rapides de l'alliage Fe$_{73.5}$Cu$_{1}$Nb$_{3}$Si$_{x}$B$_{22.5-x}$ nanocristallin. Nous avons essayé différents traitements avec deux alliages ($x=13,5$ % and $x=15,5$ %) et nous avons défini un paramètre d'optimisation du couple température/durée de recuit. Nous proposons un recuit rapide (630 $^{\circ}$C sans palier) qui permet d'améliorer les performances magnétiques et nous montrons que l'alliage contenant 15,5 % de silicium est mécaniquement plus résistant quand il est recuit de cette manière. Enfin, nous essaierons de corréler les analyses magnétiques, mécaniques et thermiques

Prognostic factors for long-term adalimumab treatment

International audienc

A Novel 8-Predictors Signature to Predict Complicated Disease Course in Pediatric-onset Crohn’s Disease: A Population-based Study

International audienceBackground The identification of patients at high risk of a disabling disease course would be invaluable in guiding initial therapy in Crohn’s disease (CD). Our objective was to evaluate a combination of clinical, serological, and genetic factors to predict complicated disease course in pediatric-onset CD. Methods Data for pediatric-onset CD patients, diagnosed before 17 years of age between 1988 and 2004 and followed more than 5 years, were extracted from the population-based EPIMAD registry. The main outcome was defined by the occurrence of complicated behavior (stricturing or penetrating) and/or intestinal resection within the 5 years following diagnosis. Lasso logistic regression models were used to build a predictive model based on clinical data at diagnosis, serological data (ASCA, pANCA, anti-OmpC, anti-Cbir1, anti-Fla2, anti-Flax), and 369 candidate single nucleotide polymorphisms. Results In total, 156 children with an inflammatory (B1) disease at diagnosis were included. Among them, 35% (n = 54) progressed to a complicated behavior or an intestinal resection within the 5 years following diagnosis. The best predictive model (PREDICT-EPIMAD) included the location at diagnosis, pANCA, and 6 single nucleotide polymorphisms. This model showed good discrimination and good calibration, with an area under the curve of 0.80 after correction for optimism bias (sensitivity, 79%, specificity, 74%, positive predictive value, 61%, negative predictive value, 87%). Decision curve analysis confirmed the clinical utility of the model. Conclusions A combination of clinical, serotypic, and genotypic variables can predict disease progression in this population-based pediatric-onset CD cohort. Independent validation is needed before it can be used in clinical practice