Caractérisation de la rupture des matériaux réfractaires sous contraintes combinées de compression et de cisaillement à hautes températures

In many industrial applications, combination of compressive and shear loads will act on refractory linings. Therefore the prediction of lining failure requires the knowledge of the multiaxial behaviour of the refractory materials under service conditions. In order to take into account those aspects in modelling, Drucker-Prager criterion is often used to describe the mechanical behaviour of granular materials. It applies a linear dependency of the shear strength on the hydrostatic pressure. Therefore the Drucker-Prager failure line requires the knowledge of two essential parameters which should be determined experimentally: the cohesion (d) representing the failure shear stress without any hydrostatic pressure, and the friction angle (b) defining the increase of the failure shear stress with hydrostatic pressure. For several materials experimental data are available in literature, especially in the field of geology or civil engineering. But, unfortunately characterization techniques applied so far are operating at ambient temperature only. For refractories, cohesion and friction angle have also to be determined at elevated temperature (up to e.g. 1500C). A simple adaptation of available experimental devices, developed for room temperature measurements, to elevated temperatures is not possible. The present work proposes a new approach to carry out such measurements in the case of refractory materials.Dans de nombreuses applications industrielles, les matériaux réfractaires subissent des contraintes combinées de compression et de cisaillement pouvant entrainer la rupture du matériau. La prédiction de la rupture du revêtement réfractaire nécessite alors la connaissance du comportement multiaxial des matériaux réfractaires dans ces conditions d utilisation. Afin de tenir compte de ces aspects dans la modélisation numérique, le critère de Drucker-Prager est souvent utilisé pour décrire le comportement mécanique des matériaux granulaires. En effet, le critère de Drucker-Prager correspond à une approche simple qui permet de décrire la dépendance de la contrainte à rupture en cisaillement en fonction de la pression hydrostatique. Néanmoins, l utilisation de ce critère nécessite la connaissance de deux paramètres essentiels qui doivent être déterminés expérimentalement : la cohésion (d) traduisant la contrainte à la rupture en cisaillement sans pression hydrostatique appliquée, et l angle de frottement (b) traduisant l évolution de cette contrainte à rupture lorsque la pression hydrostatique augmente. De nombreux travaux expérimentaux sur ce type de caractérisation sont disponibles dans la littérature, en particulier dans le domaine de la géologie ou du génie civil. Mais, malheureusement, tous ces travaux traitent de techniques de caractérisation fonctionnant à température ambiante. Dans notre cas, la cohésion et l angle de frottement doivent aussi être déterminés à haute température (jusqu à 1500C). La transposition à haute température des dispositifs développés pour des mesures à température ambiante, est tout simplement impossible. Ce travail propose donc une nouvelle approche pour réaliser de telles mesures dans le cas des matériaux réfractaires.LIMOGES-BU Sciences (870852109) / SudocSudocFranceF

From skin to microscope, case report of a rare manifestation of tophaceous gout: Miliary gout

International audienceJoint symptoms associated with gout, mostly characterized by joint flare-ups, are well known. Tophi represent the main cutaneous manifestation of gout, most often associated with a chronic and inadequately controlled disease. On rare occasions, atypical skin manifestations may occur. We present the case of a miliary form of gout in a 36-year-old man known to have hyperuricemia. Microscopic direct analysis of the skin material revealed the presence of monosodium urate (MSU) crystals. Rash disappeared with corticosteroid therapy in parallel with joint symptoms recovery. Knowledge of this unusual gout-related skin disease is essential to diagnosing uncommon presentations of gout, which sometimes occur before joint symptoms. This case highlights the importance of sampling any skin lesion suspected of being tophus, for MSU crystal identification, and provides a definitive diagnosis

From Battery Manufacturing to Smart Grids: Towards a Metaverse for the Energy Sciences**

International audienc

From Battery Manufacturing to Smart Grids: Towards a Metaverse for the Energy Sciences

We present two digital-based serious games aiming to engage students and the general public with battery sciences. The first one is a multiscale simulator in Mixed Reality of a battery-powered Electric Vehicle (EV) interacting with an Electrical Grid. One of the players drives the EV in a Virtual Reality (VR) environment where the EV can be recharged, and the other players control the electricity produced, distributed, consumed and stored by interacting with 3D-printed devices. The second serious game is a digital twin of a lithium ion battery manufacturing pilot line, which can be played from an Internet Browser or by using VR hardware. The key steps of the manufacturing process of cylindrical cells are represented in an interactive way. We discuss our games working principles, their implications for motivation, engagement and learning, and why they pave the way towards new ways of collaborative R&D in the battery field

Entering the Augmented Era: Immersive and Interactive Virtual Reality for Battery Education and Research**

International audienc

Entering the Augmented Era: Immersive and Interactive Virtual Reality for Battery Education and Research**

International audienc

Entering the Augmented Era: Immersive and Interactive Virtual Reality for Battery Education and Research

We present a series of innovative serious games we develop since four years using Virtual Reality (VR) technology to teach battery concepts at the University and also to the general public in the context of science festivals and other events. These serious games allow interacting with battery materials, electrodes and cells in a immersive way. <br /

A calpain-6/YAP axis in sarcoma stem cells that drives the outgrowth of tumors and metastases

Sarcomas include cancer stem cells, but how these cells contribute to local and metastatic relapse is largely unknown. We previously showed the pro-tumor functions of calpain-6 in sarcoma stem cells. Here, we use an osteosarcoma cell model, osteosarcoma tissues and transcriptomic data from human tumors to study gene patterns associated with calpain-6 expression or suppression. Calpain-6 modulates the expression of Hippo pathway genes and stabilizes the hippo effector YAP. It also modulates the vesicular trafficking of β-catenin degradation complexes. Calpain-6 expression is associated with genes of the G2M phase of the cell cycle, supports G2M-related YAP activities and up-regulated genes controlling mitosis in sarcoma stem cells and tissues. In mouse models of bone sarcoma, most tumor cells expressed calpain-6 during the early steps of tumor out-growth. YAP inhibition prevented the neoformation of primary tumors and metastases but had no effect on already developed tumors. It could even accelerate lung metastasis associated with large bone tumors by affecting tumor-associated inflammation in the host tissues. Our results highlight a specific mechanism involving YAP transcriptional activity in cancer stem cells that is crucial during the early steps of tumor and metastasis outgrowth and that could be targeted to prevent sarcoma relapse

Neuroepidemiology

BACKGROUND: The Gironde Central Nervous System (CNS) Tumor Registry, in collaboration with the French National Cancer Institute, is the largest population-based registry focused exclusively on primary CNS tumors in France and represents a population of 1.62 million. This report focuses on ependymal tumors to refine current knowledge and provide up-to-date data on the epidemiology of these rare tumors. MATERIAL AND METHODS: All of the ependymal tumors were extracted from the Gironde CNS Tumor Registry for the years 2000-2018. Demographic and clinical characteristics, incidence rates, and time trends as well as survival outcomes were analyzed. RESULTS: One hundred forty-four ependymal tumors were retrieved, which represented 2.3% of all the CNS tumors recorded in the same period. Histological subtype was significantly dependent on age and topography in the CNS. The median age at diagnosis was 46 years. The annual incidence rates varied between 0.15/100,000 (2004) and 0.96/100,000 (2016), with a significant increase over the study period by 4.67% per year. Five-year and 10-year OS rates were 87% and 80%, respectively. CONCLUSION: An increase in the incidence of ependymal tumors was observed over the past two decades. Further studies are needed to confirm this result and provide etiological clues

COVID-19 outcomes in patients with inflammatory rheumatic and musculoskeletal diseases treated with rituximab: a cohort study

International audienceBackground: Various observations have suggested that the course of COVID-19 might be less favourable in patients with inflammatory rheumatic and musculoskeletal diseases receiving rituximab compared with those not receiving rituximab. We aimed to investigate whether treatment with rituximab is associated with severe COVID-19 outcomes in patients with inflammatory rheumatic and musculoskeletal diseases.Methods: In this cohort study, we analysed data from the French RMD COVID-19 cohort, which included patients aged 18 years or older with inflammatory rheumatic and musculoskeletal diseases and highly suspected or confirmed COVID-19. The primary endpoint was the severity of COVID-19 in patients treated with rituximab (rituximab group) compared with patients who did not receive rituximab (no rituximab group). Severe disease was defined as that requiring admission to an intensive care unit or leading to death. Secondary objectives were to analyse deaths and duration of hospital stay. The inverse probability of treatment weighting propensity score method was used to adjust for potential confounding factors (age, sex, arterial hypertension, diabetes, smoking status, body-mass index, interstitial lung disease, cardiovascular diseases, cancer, corticosteroid use, chronic renal failure, and the underlying disease [rheumatoid arthritis vs others]). Odds ratios and hazard ratios and their 95% CIs were calculated as effect size, by dividing the two population mean differences by their SD. This study is registered with ClinicalTrials.gov, NCT04353609.Findings: Between April 15, 2020, and Nov 20, 2020, data were collected for 1090 patients (mean age 55·2 years [SD 16·4]); 734 (67%) were female and 356 (33%) were male. Of the 1090 patients, 137 (13%) developed severe COVID-19 and 89 (8%) died. After adjusting for potential confounding factors, severe disease was observed more frequently (effect size 3·26, 95% CI 1·66-6·40, p=0·0006) and the duration of hospital stay was markedly longer (0·62, 0·46-0·85, p=0·0024) in the 63 patients in the rituximab group than in the 1027 patients in the no rituximab group. 13 (21%) of 63 patients in the rituximab group died compared with 76 (7%) of 1027 patients in the no rituximab group, but the adjusted risk of death was not significantly increased in the rituximab group (effect size 1·32, 95% CI 0·55-3·19, p=0·53).Interpretation: Rituximab therapy is associated with more severe COVID-19. Rituximab will have to be prescribed with particular caution in patients with inflammatory rheumatic and musculoskeletal diseases