High spatial resolution strain measurements at the surface of duplex stainless steels

International audienceThe determination of local strain fields at the surface of materials is of major importance for understanding their reactivity. In the present paper, lithography is used to fabricate grid points at the microscale and to map strain gradients within grains and between grains. This method was applied to duplex stainless steels which exhibit heterogeneous strain distributions under straining conditions. The influence of various parameters (the specimen microstructure, the density of slip bands, the number of systems activated and the grid geometry) on the strain value was discussed

Double-outlet right ventricle and double septal defects in a Rhesus macaque (Macaca mulatta)

Double-outlet right ventricle (DORV) is a rare form of congenital heart defect, in which both great arteries (aorta and pulmonary trunk) arise from the right ventricle. The defect affects 1-1.5% of patients with congenital heart disease with a frequency of 1 in 10,000 live births in human beings. A 6-year-old male India-origin Rhesus macaque (Macaca mulatta) with no history of illness or trauma presented for project pre-assignment physical examination from the outdoor breeding colony at the Tulane National Primate Research Center (Covington, Louisiana). Upon physical examination, the animal was found to have poor body condition with a body condition score of 1 out of 5. Thoracic auscultation revealed caudal displacement of the heart with a grade VI/VI pansystolic murmur bilaterally. Thoracic radiographs showed a globoid heart with significant enlargement of the left atrium, left auricle, and both ventricles. The aortic shadow was not prominent, but the pulmonary artery trunk was enlarged ( Grossly, the animal was severely emaciated and dehydrated with diffuse muscular atrophy. The skin and external mucosa were moderately cyanotic. The heart was markedly enlarged and globoid with severe dilation of the left atrium and auricle and marked enlargement of both ventricles. Externally, the ascending aorta lay nearly parallel, right, and slightly posterior to the dilated and thin-walled pulmonary trun

Clinical epidemiology of laboratory-confirmed Buruli ulcer in Benin: a cohort study

Background Buruli ulcer, caused by Mycobacterium ulcerans, was identifi ed as a neglected emerging infectious disease by WHO in 1998. Although Buruli ulcer is the third most common mycobacterial disease worldwide, understanding of the disease is incomplete. We analysed a large cohort of laboratory-confi rmed cases of Buruli ulcer from Pobè, Benin, to provide a comprehensive description of the clinical presentation of the disease, its variation with age and sex, and its eff ect on the occurrence of permanent functional sequelae. Methods Between Jan 1, 2005, and Dec 31, 2011, we prospectively collected clinical and laboratory data from all patients with Buruli ulcer diagnosed at the Centre de Dépistage et de Traitement de l’Ulcère de Buruli in Pobè, Benin. We followed up patients to assess the frequency of permanent functional sequelae. All analyses were done on cases that were laboratory confi rmed. Findings 1227 cases of laboratory-confi rmed Buruli ulcer were included in the analysis. Typically, patients with Buruli ulcer were children (median age at diagnosis 12 years) presenting with a unique (1172 [96%]) large (≥15 cm, 444 [36%]) ulcerative (805 [66%]) lesion of the lower limb (733 [60%]). Atypical clinical presentation of Buruli ulcer included Buruli ulcer osteomyelitis with no identifi able present or past Buruli ulcer skin lesions, which was recorded in at least 14 patients. The sex ratio of Buruli ulcer widely varied with age, with male patients accounting for 57% (n=427) of patients aged 15 years and younger, but only 33% (n=158) of those older than 15 years (odds ratio [OR] 2·59, 95% CI 2·04–3·30). Clinical presentation of Buruli ulcer was signifi cantly dependent on age and sex. 54 (9%) male patients had Buruli ulcer osteomyelitis, whereas only 28 (4%) of female patients did (OR 2·21, 95% CI 1·39–3·59). 1 year after treatment, 229 (22% of 1043 with follow-up information) patients presented with permanent functional sequelae. Presentation with oedema, osteomyelitis, or large (≥15 cm in diameter), or multifocal lesions was signifi cantly associated with occurrence of permanent functional sequelae (OR 7·64, 95% CI 5·29–11·31) and operationally defi nes severe Buruli ulcer. Interpretation Our fi ndings have important clinical implications for daily practice, including enhanced surveillance for early detection of osteomyelitis in boys; systematic search for M ulcerans in osteomyelitis cases of non-specifi c aspect in areas endemic for Buruli ulcer; and specifi c disability prevention for patients presenting with osteomyelitis, oedema, or multifocal or large lesions. Our fi ndings also suggest a crucial underestimation of the burden of Buruli ulcer in Africa and raise key questions about the contribution of environmental and physiopathological factors to the recorded heterogeneity of the clinical presentation of Buruli ulcer

Real-Time Microbiology Laboratory Surveillance System to Detect Abnormal Events and Emerging Infections, Marseille, France

International audienceInfectious diseases are a major threat to humanity, and accurate surveillance is essential. We describe how to implement a laboratory data–based surveillance system in a clinical microbiology laboratory. Two historical Microsoft Excel databases were implemented. The data were then sorted and used to execute the following 2 surveillance systems in Excel: the Bacterial real-time Laboratory-based Surveillance System (BALYSES) for monitoring the number of patients infected with bacterial species isolated at least once in our laboratory during the study periodl and the Marseille Antibiotic Resistance Surveillance System (MARSS), which surveys the primary β-lactam resistance phenotypes for 15 selected bacterial species. The first historical database contained 174,853 identifications of bacteria, and the second contained 12,062 results of antibiotic susceptibility testing. From May 21, 2013, through June 4, 2014, BALYSES and MARSS enabled the detection of 52 abnormal events for 24 bacterial species, leading to 19 official reports. This system is currently being refined and improved

Carbapenem Resistance and Acinetobacter baumannii in Senegal: The Paradigm of a Common Phenomenon in Natural Reservoirs

Incidence of carbapenem-resistant Acinetobacter baumannii is rising in several parts of the world. In Africa, data concerning this species and its resistance to carbapenems are limited. The objective of the present study was to identify the presence of A. baumannii carbapenem-resistant encoding genes in natural reservoirs in Senegal, where antibiotic pressure is believed to be low. From October 2010 to January 2011, 354 human head lice, 717 human fecal samples and 118 animal fecal samples were screened for the presence of A. baumannii by real time PCR targeting blaOXA51-like gene. For all samples positive for A. baumannii, the carbapenemase-hydrolysing oxacillinases blaOXA23-like and blaOXA24-like were searched for and sequenced, and the isolates harbouring an oxacillinase were genotyped using PCR amplification and sequencing of recA gene. The presence of A. baumannii was detected in 4.0% of the head lice, in 5.4% of the human stool samples and in 5.1% of the animal stool samples tested. No blaOXA24 gene was detected but six fecal samples and three lice were positive for blaOXA23-like gene. The blaOXA23-like gene isolated in lice was likely a new oxacillinase sequence. Finally, the A. baumannii detected in stools were all of recA genotype 3 and those detected in lice, of recA genotype 4. This study shows for the first time a reservoir of blaOXA23-like-positive gene in human head lice and stool samples in Senegal

Comparative in vitro activity of Meropenem, Imipenem and Piperacillin/tazobactam against 1071 clinical isolates using 2 different methods: a French multicentre study

<p>Abstract</p> <p>Background</p> <p>Meropenem is a carbapenem that has an excellent activity against many gram-positive and gram-negative aerobic, facultative, and anaerobic bacteria. The major objective of the present study was to assess the <it>in vitro </it>activity of meropenem compared to imipenem and piperacillin/tazobactam, against 1071 non-repetitive isolates collected from patients with bacteremia (55%), pneumonia (29%), peritonitis (12%) and wound infections (3%), in 15 French hospitals in 2006. The secondary aim of the study was to compare the results of routinely testings and those obtained by a referent laboratory.</p> <p>Method</p> <p>Susceptibility testing and Minimum Inhibitory Concentrations (MICs) of meropenem, imipenem and piperacillin/tazobactam were determined locally by Etest method. Susceptibility to meropenem was confirmed at a central laboratory by disc diffusion method and MICs determined by agar dilution method for meropenem, imipenem and piperacillin/tazobactam.</p> <p>Results</p> <p>Cumulative susceptibility rates against <it>Escherichia coli </it>were, meropenem and imipenem: 100% and piperacillin/tazobactam: 90%. Against other <it>Enterobacteriaceae</it>, the rates were meropenem: 99%, imipenem: 98% and piperacillin/tazobactam: 90%. All <it>Staphylococci</it>, <it>Streptococci </it>and anaerobes were susceptible to the three antibiotics. Against non fermeters, meropenem was active on 84-94% of the strains, imipenem on 84-98% of the strains and piperacillin/tazobactam on 90-100% of the strains.</p> <p>Conclusions</p> <p>Compared to imipenem, meropenem displays lower MICs against <it>Enterobacteriaceae</it>, <it>Escherichia coli </it>and <it>Pseudomonas aeruginosa</it>. Except for non fermenters, MICs90 of carbapenems were <4 mg/L. Piperacillin/tazobactam was less active against <it>Enterobacteriaceae </it>and <it>Acinetobacter </it>but not <it>P. aeruginosa</it>. Some discrepancies were noted between MICs determined by Etest accross centres and MICs determined by agar dilution method at the central laboratory. Discrepancies were more common for imipenem testing and more frequently related to a few centres. Overall MICs determined by Etest were in general higher (0.5 log to 1 log fold) than MICs by agar dilution.</p

Working group on ecosystem assessment of Western European shelf seas (WGEAWESS)

The ICES Working Group on Ecosystem Assessment of Western European Shelf Seas (WGEA-WESS) aims to provide high quality science in support to holistic, adaptive, evidence-based man-agement in the Celtic seas, Bay of Biscay and Iberian coast regions. The group works towards developing integrated ecosystem assessments for both the (i) Celtic Seas and (ii) Bay of Biscay and Iberian Coast which are summarized in the Ecosystem Overviews (EOs) advice products that were recently updated. Integrated Trend Analysis (ITA) were performed for multiple sub-ecoregions and used to develop an understanding of ecosystem responses to pressures at varying spatial scales. Ecosystem models (primarily Ecopath with Ecosim; EwE) were developed and identified for fisheries and spatial management advice. The updated Celtic Seas EO represents a large step forward for EOs, with the inclusion of novel sections on climate change, foodweb and productivity, the first application of the new guidelines for building the conceptual diagram, inclusion of socio-economic indicators, and progress made toward complying with the Transparent Assessment Framework (TAF). We highlight ongoing issues relevant to the development and communication of EO conceptual diagrams. A common methodology using dynamic factor analysis (DFA) was used to perform ITA in a comparable way for seven subregions. This was supported by the design and compilation of the first standardized cross-regional dataset. A comparison of the main trends evidenced among subregions over the period 1993–2020 was conducted and will be published soon. A list of available and developing EWE models for the region was also generated. Here, we re-port on the advances in temporal and spatial ecosystem modelling, such as their capacity to model the impacts of sector activities (e.g. renewables and fisheries) and quantify foodweb indi-cators. We also reflect on model quality assessment with the key run of the Irish sea EwE model. The group highlighted the hurdles and gaps in current models in support of EBM, such as the choice of a relevant functional, spatial, and temporal scales and the impacts of model structure on our capacity to draw comparisons from models of different regions. The group aims to ad-dress these issues in coming years and identify routes for ecosystem model derived information into ICES advice.info:eu-repo/semantics/publishedVersio

Caractérisation mécanique des surfaces et interfaces aux échelles micrométrique et nanométrique (étude des processus d oxydation et de piqûration)

Prédire la durée de vie des alliages métalliques nécessite de comprendre les rôles des paramètres mécaniques, physiques et chimiques dans l amorçage et la propagation des piqûres. L objectif de ce travail est de développer de nouvelles méthodes d analyse en mécanique aux échelles microscopiques pour cartographier les gradients de déformation et les propriétés mécaniques à la surface des alliages métalliques, en prenant en compte leur microstructure complexe. Ces méthodes seront appliquées a l étude des processus d oxydation et de piqûration et des critères mécano-électrochimique seront proposés. Dans un premier temps, les gradients de déformation liés à l application d un chargement mécanique dans le domaine plastique sont cartographiés aux échelles microscopiques à l aide des micro-jauges métalliques. Les relations entre la microstructure, les déformations plastiques et les mécanismes de piqûration sont ensuite étudiées. Dans un deuxième temps, l influence de la microstructure sur les mécanismes d oxydation des aciers inoxydables duplex a été quantifiée à l échelle microscopique. Des réseaux de plots non métalliques ont été utilisés pour cartographier les déformations à l interface entre le substrat et le film d oxydes sur des éprouvettes oxydées thermiquement. La technique de spectroscopie Auger locale a été utilisée pour quantifier les épaisseurs et les compositions des films d oxydes. Afin d identifier les lois de comportement des alliages métalliques à l échelle des grains, des tests de nano-indentation avec plusieurs géométries d indenteurs ont été effectués et analysés selon des modèles issus de la littérature. En couplant la nano-indentation à la diffraction des rayons X et à la simulation numérique par éléments finis du test de nano-indentation, nous avons adapté les modèles existants pour déterminer les propriétés élasto-plastiques du matériau. Un premier modèle numérique par éléments finis prédictif a alors été développé.To predict the service time of metallic alloys, a multi-disciplinary approach is essential. The roles of mechanical, physical and chemical parameters on pit initiation will be studied. The aim of this present work is to develop new mechanical methodologies at the microscopic scale to quantify the strain gradients and the mechanical properties of the alloy surfaces. These specific methodologies will be applied to the study of the influence of the microstructure and the mechanics in the oxidation and pit initiation process. First, strain gradients induced by a mechanical solicitation will be quantified at the microscopic scale using the grating method (with metallic dots of 70 nm in diameter). A study on the influence of the heterogeneous strain fields and microstructure on pit initiation is proposed. Second, the influence of microstructure and strain mapping on the oxidation process of duplex stainless steel at the microscopic scale was studied. Grating method with non-metallic dots was used to map the heterogeneous strain field at the interface between the substrate and the thermal-oxide film. Local Auger spectroscopy was used to determine the thickness and the compositions of oxide films. At last, nano-indentation tests have been done to identify the behaviour laws of the duplex stainless steel at the grain scale. Many tests have been done with different indenter geometries in order to apply the analytical models available in the literature. The elasto-plastic parameters have been determined coupling the nano-indentation test with X-ray diffraction and finite element simulation of the nano-indentation test. Then, the grain rheologies founded have been inserted in a predictive finite element model of the duplex stainless steel behavior.DIJON-BU Sciences Economie (212312102) / SudocSudocFranceF