Influence de la teneur en oxygène sur la microstructure et le comportement mécanique de la phase « ex bêta » résultant de l'oxydation à haute température (1000-1200°C) du zircaloy 4

International audienceL'étude ici illustrée s'intéresse au comportement thermo - métallurgique - mécanique des alliages de Zr des tubes de gainage du combustible des Réacteurs nucléaires à Eau Pressurisée (REP), lors de transitoires à hautes températures (HT) en ambiance vapeur d'eau, simulant des conditions hypothétiques accidentelles (dites APRP). Il apparaît intéressant d'approfondir la connaissance des phénomènes métallurgiques et thermomécaniques mis en jeu lors de tels transitoires, en particulier vis-à-vis du comportement mécanique résiduel « post oxydation trempe ». Différentes teneurs en oxygène ont été incorporées dans l'alliage étudié, pour simuler la diffusion de cet élément dans le substrat métallique qui intervient lors de l'oxydation HT. Des caractérisations microstructurales par EBSD, MET, MEB... et des caractérisations mécaniques par essai de traction, mesures de constantes physiques... ont permis de décrire la microstructure et le comportement mécanique de la phase résiduelle la plus ductile – phase dite « ex-bêta » - résultant de l'oxydation HT des gaines en zircaloy-4

PKU dietary handbook to accompany PKU guidelines

Background: Phenylketonuria (PKU) is an autosomal recessive inborn error of phenylalanine metabolism caused by deficiency in the enzyme phenylalanine hydroxylase that converts phenylalanine into tyrosine. Main body: In 2017 the first European PKU Guidelines were published. These guidelines contained evidence based and/or expert opinion recommendations regarding diagnosis, treatment and care for patients with PKU of all ages. This manuscript is a supplement containing the practical application of the dietary treatment. Conclusion: This handbook can support dietitians, nutritionists and physicians in starting, adjusting and maintaining dietary treatment

Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London

Defining tetrahydrobiopterin responsiveness in phenylketonuria: Survey results from 38 countries

Background: A subset of patients with phenylketonuria benefit from treatment with tetrahydrobiopterin (BH 4), although there is no consensus on the definition of BH 4 responsiveness. The aim of this study therefore was to gain insight into the definitions of long-term BH 4 responsiveness being used around the world. Methods: We performed a web-based survey targeting healthcare professionals involved in the treatment of PKU patients. Data were analysed according to geographical region (Europe, USA/Canada, other). Results: We analysed 166 responses. Long-term BH 4 responsiveness was commonly defined using natural protein tolerance (95.6%), improvement of metabolic control (73.5%) and increase in quality of life (48.2%). When a specific value for a reduction in phenylalanine concentrations was reported (n = 89), 30% and 20% were most frequently used as cut-off values (76% and 19% of respondents, respectively). When a specific relative increase in natural protein tolerance was used to define long-term BH 4 responsiveness (n = 71), respondents most commonly reported cut-off values of 30% and 100% (28% of respondents in both cases). Respondents from USA/Canada (n = 50) generally used less strict cut-off values compared to Europe (n = 96). Furthermore, respondents working within the same center answered differently. Conclusion: The results of this study suggest a very heterogeneous situation on the topic of defining long-term BH 4 responsiveness, not only at a worldwide level but also within centers. Developing a strong evidence- and consensus-based definition would improve the quality of BH 4 treatment

Endocrine Disruptor Regulation of MicroRNA Expression in Breast Carcinoma Cells

Several environmental agents termed "endocrine disrupting compounds" or EDCs have been reported to bind and activate the estrogen receptor-α (ER). The EDCs DDT and BPA are ubiquitously present in the environment, and DDT and BPA levels in human blood and adipose tissue are detectable in most if not all women and men. ER-mediated biological responses can be regulated at numerous levels, including expression of coding RNAs (mRNAs) and more recently non-coding RNAs (ncRNAs). Of the ncRNAs, microRNAs have emerged as a target of estrogen signaling. Given the important implications of EDC-regulated ER function, we sought to define the effects of BPA and DDT on microRNA regulation and expression levels in estrogen-responsive human breast cancer cells.To investigate the cellular effects of DDT and BPA, we used the human MCF-7 breast cancer cell line, which is ER (+) and hormone sensitive. Our results show that DDT and BPA potentiate ER transcriptional activity, resulting in an increased expression of receptor target genes, including progesterone receptor, bcl-2, and trefoil factor 1. Interestingly, a differential increase in expression of Jun and Fas by BPA but not DDT or estrogen was observed. In addition to ER responsive mRNAs, we investigated the ability of DDT and BPA to alter the miRNA profiles in MCF-7 cells. While the EDCs and estrogen similarly altered the expression of multiple microRNAs in MCF-7 cells, including miR-21, differential patterns of microRNA expression were induced by DDT and BPA compared to estrogen.We have shown, for the first time, that BPA and DDT, two well known EDCs, alter the expression profiles of microRNA in MCF-7 breast cancer cells. A better understanding of the molecular mechanisms of these compounds could provide important insight into the role of EDCs in human disease, including breast cancer