561 research outputs found

    Influence of Post-Welding Heat Treatment on the Corrosion Behavior of a 2050-T3 Aluminum-Copper-Lithium Alloy Friction Stir Welding Joint

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    The corrosion behavior of a Friction Stir Welding joint in 2050-T3 Al-Cu-Li alloy was studied in 1 M NaCl solution and the influence of T8 post-welding heat treatment on its corrosion susceptibility was analyzed. After exposure to 1 M NaCl solution, the heat affected zone (HAZ) of the weld without post-welding heat treatment was found to be the most extensively corroded zone with extended intergranular corrosion damage while, following T8 post-welding heat treatment, no intergranular corrosion was observed in the HAZ and the global corrosion behavior of the weld was significantly improved. The corrosion damage observed on the welded joints after immersion in 1 M NaCl solution was compared to that obtained after 750 h Mastmaasis Wet Bottom tests. The same corrosion damage was observed. Various stationary electrochemical tests were carried out on the global welded joint and/or each of the metallurgical zones of the welded joint to understand the corrosion damage observed. TEM observations helped in bringing meaningful elements to analyze the intrinsic electrochemical behavior of the different zones of the weld related to their microstructure. However, galvanic coupling tests showed that galvanic coupling effects between the different zones of the weld were at least partially responsible for its corrosion behavior

    EOLES Course, 4 years and going…results and experiences

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    The EOLES (Electronics and Optics e-Learning for Embedded Systems) course consists of a 3rd year Bachelor degree that relies exclusively on e-learning and remote laboratories, developed as the result of an EU funded ERASMUS+ project, involving 15 institutions from four European and three North African countries and concluded in 2015. The developed course was accredited as a specialization year in most partner institutions and has been running non-stop since then, mainly with students from North African institutions. Although no longer supported by an EU project, the course is a good example of sustainability as it already had 4 effective editions with successful approval rates and always with many more candidates than available vacancies. This paper presents an overview and overall results for this initial period and a more detailed analysis of the Digital Systems Teaching Unit. The focus is on the course specific characteristics and features, student and teacher experiences and the methodologies that were applied to enhance learning results. Although being a fully online course, several synchronous activities and communication tools are included in the methodology to enhance student and teacher iteration and also to provide an impartial grading process, as required for accreditation. The course expositive material is provided as the student progresses, with progressive unlocking of content depending on each teaching unit timeline, and automatic quizzes results. In short, students are allowed and encouraged to adjust their learning rhythm within the limits allowed by time restraints and evaluation criteria.info:eu-repo/semantics/publishedVersio

    EOLES Course, 4 years and going…results and experiences

    Get PDF
    The EOLES (Electronics and Optics e-Learning for Embedded Systems) course consists of a 3rd year Bachelor degree that relies exclusively on e-learning and remote laboratories, developed as the result of an EU funded ERASMUS+ project, involving 15 institutions from four European and three North African countries and concluded in 2015. The developed course was accredited as a specialization year in most partner institutions and has been running non-stop since then, mainly with students from North African institutions. Although no longer supported by an EU project, the course is a good example of sustainability as it already had 4 effective editions with successful approval rates and always with many more candidates than available vacancies. This paper presents an overview and overall results for this initial period and a more detailed analysis of the Digital Systems Teaching Unit. The focus is on the course specific characteristics and features, student and teacher experiences and the methodologies that were applied to enhance learning results. Although being a fully online course, several synchronous activities and communication tools are included in the methodology to enhance student and teacher iteration and also to provide an impartial grading process, as required for accreditation. The course expositive material is provided as the student progresses, with progressive unlocking of content depending on each teaching unit timeline, and automatic quizzes results. In short, students are allowed and encouraged to adjust their learning rhythm within the limits allowed by time restraints and evaluation criteria.info:eu-repo/semantics/publishedVersio

    Parallel targeted and non-targeted quantitative analysis of steroids in human serum and peritoneal fluid by liquid chromatography high-resolution mass spectrometry

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    We developed and validated a liquid chromatography high-resolution mass spectrometry method for the absolute quantification of 51 steroids for clinical analysis of human serum and, for the first time, peritoneal fluid. Data acquisition was performed in both targeted and untargeted mode simultaneously, thus allowing the accurate and precise quantification of the main components of the classical steroid pathways (17 steroids) as well as the analysis of 34 additional non-classical steroids. For targeted analysis, validation was performed according to FDA guidelines, resulting, among other parameters, in accuracy < 13% RSD and precision < 10% relative error, for both inter- and intra-day validation runs. By establishing steroid-specific response factors, the calibration curves of the targeted analytes can be extended to untargeted analytes. This approach opens novel possibilities for the post hoc analysis of clinical samples as the data can be examined for virtually any steroid even after data acquisition, enabling facile absolute quantification once a standard becomes available. We demonstrate the applicability of the approach to evaluate the differences in steroid content between peripheral serum and peritoneal fluid across the menstrual cycle phases, as well as the effect of the synthetic gestagen dienogest on the steroid metabolome. GRAPHICAL ABSTRACT: [Image: see text] SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s00216-022-03881-3

    Reproducible formation of single magnetic bubbles in an array of patterned dots

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    International audienceThe formation conditions of single magnetic bubbles through in-plane field demagnetizationare investigated in an array of Co/Ni circular dots by magnetic force microscopy andcompared to micromagnetic calculations. We demonstrate high success rates in nucleatingstable bubbles. The efficiency of single bubble formation is found to depend not only on thedot size, material thickness and intrinsic material parameters but also on the bubble nucleationpath. Experimental phase diagrams and micromagnetic calculations highlight the influenceof the starting in-plane field amplitude and dipolar interactions in stabilizing the bubble.The identification of a systematic procedure for controlling nucleation of single bubbles,multidomain states or a uniform state is important from a technological point of view, openinga path toward the realization of reprogrammable magnonic crystals for the control of spinwavepropagation

    Cell Cycle Phase-Specific Surface Expression of Nerve Growth Factor Receptors TrkA and p75NTR

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    [EN]Expression of the nerve growth factor (NGF) receptors TrkA and p75NTR was found to vary at the surface of PC12 cells in a cell cycle phase-specific manner. This was evidenced by using flow cytometric and microscopic analysis of cell populations labeled with antibodies to the extracellular domains of both receptors. Differential expression of these receptors also was evidenced by biotinylation of surface proteins and Western analysis, using antibodies specific for the extracellular domains of TrkA and p75NTR. TrkA is expressed most strongly at the cell surface in M and early G1 phases, whereas p75NTR is expressed mainly in late G1, S, and G2 phases. This expression reflects the molecular and cellular responses to NGF in specific phases of the cell cycle; in the G1 phase NGF elicits both the anti-mitogenic effect, i.e., inhibition of the G1 to S transition, and the differentiation response whereas a survival effect is provoked elsewhere in the cell cycle. A model is proposed relating these responses to the surface expression of the two receptors. These observations open the way for novel approaches to the investigation of the mechanism of NGF signal transduction

    Oral Condition and Incident Coronary Heart Disease: A Clustering Analysis

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    Poor oral health has been linked to coronary heart disease (CHD). Clustering clinical oral conditions routinely recorded in adults may identify their CHD risk profile. Participants from the Paris Prospective Study 3 received, between 2008 and 2012, a baseline routine full-mouth clinical examination and an extensive physical examination and were thereafter followed up every 2 y until September 2020. Three axes defined oral health conditions: 1) healthy, missing, filled, and decayed teeth; 2) masticatory capacity denoted by functional masticatory units; and 3) gingival inflammation and dental plaque. Hierarchical cluster analysis was performed with multivariate Cox proportional hazards regression models and adjusted for age, sex, smoking, body mass index, education, deprivation (EPICES score; Evaluation of Deprivation and Inequalities in Health Examination Centres), hypertension, type 2 diabetes, LDL and HDL serum cholesterol (low- and high-density lipoprotein), triglycerides, lipid-lowering medications, NT-proBNP and IL-6 serum level. A sample of 5,294 participants (age, 50 to 75 y; 37.10% women) were included in the study. Cluster analysis identified 3,688 (69.66%) participants with optimal oral health and preserved masticatory capacity (cluster 1), 1,356 (25.61%) with moderate oral health and moderately impaired masticatory capacity (cluster 2), and 250 (4.72%) with poor oral health and severely impaired masticatory capacity (cluster 3). After a median follow-up of 8.32 y (interquartile range, 8.00 to 10.05), 128 nonfatal incident CHD events occurred. As compared with cluster 1, the risk of CHD progressively increased from cluster 2 (hazard ratio, 1.45; 95% CI, 0.98 to 2.15) to cluster 3 (hazard ratio, 2.47; 95% CI, 1.34 to 4.57; P < 0.05 for trend). To conclude, middle-aged individuals with poor oral health and severely impaired masticatory capacity have more than twice the risk of incident CHD than those with optimal oral health and preserved masticatory capacity (ClinicalTrials.gov NCT00741728)
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