Effect of cobalt addition on the magneto-crystalline anisotropy parameter of sintered NiZn ferrites evaluated from magnetization curves

International audienc

Modeling of demagnetization processes in permanent magnets measured in closed-circuit geometry

International audienceThe hysteresis loops of nucleation-type magnets made of exchange-decoupled grains (i.e. sintered Nd-Fe-B magnets) reflect the discrete character of magnetization switching in such materials. Due to this discrete character, the experimental determination of coercivity depends on the measurement protocol. Finite element modelling allows to investigate how the pattern of reversed grains develops during sample demagnetization performed under closed-circuit conditions, provided that the basic features of the hysteresigraph are known. Numerical modelling provides a quantitative understanding of the collective effects which are very pronounced in the closed-circuit configuration and shows how they affect both the slope of the demagnetizing curve and the sample coercivity. With a grain coercive field standard deviation adjusted to 0.1 T, it is numerically found that the difference in coercivity between closed-and open-circuit configurations is 40 kA/m, in good agreement with previous experimental data

Revisiting the demagnetization curves of Dy-diffused Nd-Fe-B sintered magnets

International audienc

Cost of detecting malignant lesions by endoscopy in 2741 primary care dyspeptic patients without alarm symptoms.

BACKGROUND & AIMS: Current guidelines recommend empirical, noninvasive approaches to manage dyspeptic patients without alarm symptoms, but concerns about missed lesions persist; the cost savings afforded by noninvasive approaches must be weighed against treatment delays. We investigated the prevalence of malignancies and other serious abnormalities in patients with dyspepsia and the cost of detecting these by endoscopy. METHODS: We studied 2741 primary-care outpatients, 18-70 years in age, who met Rome II criteria for dyspepsia. Patients with alarm features (dysphagia, bleeding, weight loss, etc) were excluded. All patients underwent endoscopy. The cost and diagnostic yield of an early endoscopy strategy in all patients were compared with those of endoscopy limited to age-defined cohorts. Costs were calculated for a low, intermediate, and high cost environment. RESULTS: Endoscopies detected abnormalities in 635 patients (23%). The most common findings were reflux esophagitis with erosions (15%), gastric ulcers (2.7%), and duodenal ulcers (2.3%). The prevalence of upper gastrointestinal malignancy was 0.22%. If all dyspeptic patients 50 years or older underwent endoscopy, 1 esophageal cancer and no gastric cancers would have been missed. If the age threshold for endoscopy were set at 50 years, at a cost of $500/endoscopy, it would cost$82,900 (95% CI, $35,714-$250,000) to detect each case of cancer. CONCLUSIONS: Primary care dyspeptic patients without alarm symptoms rarely have serious underlying conditions at endoscopy. The costs associated with diagnosing an occult malignancy are large, but an age cut-off of 50 years for early endoscopy provides the best assurance that an occult malignancy will not be missed

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