Approche thermodynamique du procédé de lixiviation pour la récupération des métaux - Cas de la chalcopyrite

Dans le domaine de l’hydrométallurgie, le développement d’un procédé de lixiviation du minerai de chalcopyrite, CuFeS2, revêt une importance industrielle majeure. Comme pour d’autres minerais, son efficacité est limitée par la formation de couches de surface solides, qui ralentissent ou bloquent la dissolution. De multiples études ont été menées pour identifier la nature des couches passivantes et les conditions opératoires qui favorisent leur formation, mais de nombreuses inconnues et contradictions persistent. Dans le but de voir s’il existe une fenêtre opératoire industriellement exploitable pour traiter la chalcopyrite en voie aqueuse, une méthodologie sur la modélisation thermodynamique de la lixiviation est en cours de développement. Cet article en présente les articulations principales. Le travail réalisé a permis d’identifier quelques points clés, dont certains sont discutés dans le texte. En croisant deux outils de simulation d’équilibres thermodynamiques, PhreeqC et FactSage, qui utilisent des approches de calcul et des bases de données thermodynamiques différentes, l’analyse fait apparaître une divergence importante sur la prédiction d’une des frontières phase aqueuse/phase solide dans le système le plus complet : Cu-Fe-S-H2O, système critique pour modéliser la lixiviation de la chalcopyrite. Pour mieux comprendre cet écart, des simulations de complexité croissante ont été mises en oeuvre : les sous-systèmes constitutifs ont été examinés un par un par confrontation à des données de la littérature. L’étude du système Fe-S-H2O a notamment révélé des espèces prédominantes en solution propres à chaque base de données. En particulier, aucune des configurations de calcul n’a permis de reproduire un jeu de données expérimentales portant sur la solubilité de la goethite, FeOOH, dans un solvant eau-acide sulfurique. Afin de déterminer les modifications éventuelles à apporter aux modèles ou bases utilisés, des mesures expérimentales complémentaires s’avèrent indispensable

Les pratiques récentes de mixité entre art actuel et art ancien : le contemporain dans les musées

Pendant longtemps, les musées ont séparé l’art du passé et l’art du présent, celui-ci étant exposé seulement dans des musées dont le nom même – musée d’art moderne ou d’art contemporain – signalait cette séparation. Depuis quelque temps pourtant, singulièrement en France mais pas uniquement, de nombreux musées se sont mis à montrer au sein de leurs collections permanentes des œuvres d’art créées très récemment voire réalisées spécialement pour l’occasion. Trois conservateurs et un artiste, qu..

ILC2-modulated T cell-to-MDSC balance is associated with bladder cancer recurrence.

Non-muscle-invasive bladder cancer (NMIBC) is a highly recurrent tumor despite intravesical immunotherapy instillation with the bacillus Calmette-Guérin (BCG) vaccine. In a prospective longitudinal study, we took advantage of BCG instillations, which increase local immune infiltration, to characterize immune cell populations in the urine of patients with NMIBC as a surrogate for the bladder tumor microenvironment. We observed an infiltration of neutrophils, T cells, monocytic myeloid-derived suppressor cells (M-MDSCs), and group 2 innate lymphoid cells (ILC2). Notably, patients with a T cell-to-MDSC ratio of less than 1 showed dramatically lower recurrence-free survival than did patients with a ratio of greater than 1. Analysis of early and later time points indicated that this patient dichotomy existed prior to BCG treatment. ILC2 frequency was associated with detectable IL-13 in the urine and correlated with the level of recruited M-MDSCs, which highly expressed IL-13 receptor α1. In vitro, ILC2 were increased and potently expressed IL-13 in the presence of BCG or tumor cells. IL-13 induced the preferential recruitment and suppressive function of monocytes. Thus, the T cell-to-MDSC balance, associated with a skewing toward type 2 immunity, may predict bladder tumor recurrence and influence the mortality of patients with muscle-invasive cancer. Moreover, these results underline the ILC2/IL-13 axis as a targetable pathway to curtail the M-MDSC compartment and improve bladder cancer treatment

Kinetics and persistence of the cellular and humoral immune responses to BNT162b2 mRNA vaccine in SARS-CoV-2-naive and -experienced subjects

Background: Understanding and measuring the individual level of immune protection and its persistence at both humoral and cellular levels after SARS-CoV-2 vaccination is mandatory for the management of the vaccination booster campaign. Our prospective study was designed to assess the immunogenicity of the BNT162b2 mRNA vaccine in triggering the humoral and the cellular immune response in healthcare workers up to 6 months after two doses vaccination. Methods: This prospective study enrolled 208 healthcare workers from the Liège University Hospital (CHU) of Liège in Belgium. All participants received two doses of BioNTech/Pfizer COVID-19 vaccine (BNT162b2). Fifty participants were SARS-CoV-2 experienced (self-reported SARS-CoV-2 infection) and 158 were naïve (no reported SARS-CoV-2 infection) before the vaccination. Blood sampling was performed at the day of the first (T0) and second (T1) vaccine doses administration, then at 2 weeks (T2), 4 weeks (T3) and 6 months (T4) after the 1st vaccine dose administration. A total of 1024 blood samples were collected. All samples were tested for the presence of anti-Spike antibodies using DiaSorin LIAISON SARS-CoV-2 TrimericS IgG assay. Neutralizing antibodies against the SARS-CoV-2 Wuhan-like variant strain were quantified in all samples using a Vero E6 cell-based neutralization-based assay. Cell-mediated immune response was evaluated at T4 on 80 participants by measuring the secretion of IFN- on peripheral blood lymphocytes using the QuantiFERON Human IFN- SARS-CoV-2, Qiagen. All participants were monitored on weekly-basis for the novo SARS-COV-2 infection for 4 weeks after the 1st vaccine dose administration. We analyzed separately the naïve and experienced participants. Findings: We found that anti-spike antibodies and neutralization capacity levels were significantly higher in SARS-CoV-2 experienced healthcare workers (HCWs) compared to naïve HCWs at all time points analyzed. Cellular immune response was similar in the two groups six months following 2nd dose of the vaccine. Reassuringly, most participants had a detectable cellular immune response to SARS-CoV-2 six months after vaccination. Besides the impact of SARS-CoV-2 infection history on immune response to BNT162b2 mRNA vaccine, we observed a significant negative correlation between age and persistence of humoral response. Cellular immune response was, however, not significantly correlated to age, although a trend towards a negative impact of age was observed. Conclusions: Our data strengthen previous findings demonstrating that immunization through vaccination combined with natural infection is better than 2 vaccine doses immunization or natural infection alone. It may have implications for personalizing mRNA vaccination regimens used to prevent severe COVID-19 and reduce the impact of the pandemic on the healthcare system. More specifically, it may help prioritizing vaccination, including for the deployment of booster doses

Data from: Hormonal pleiotropy and the evolution of allocation trade-offs

Recent empirical evidence suggest that trade-off relationships can evolve, challenging the classical image of their high entrenchment. For energy reliant traits, this relationship should depend on the endocrine system that regulates resource allocation. Here we model changes in this system by mutating the expression and conformation of its constitutive hormones and receptors. We show that the shape of trade-offs can indeed evolve in this model through the combined action of genetic drift and selection, such that their evolutionarily expected curvature and length depend on context. In particular, the shape of a trade- off should depend on the cost associated with resource storage, itself depending on the traded resource and on the ecological context. Despite this convergence at the phenotypic level, we show that a variety of physiological mechanisms may evolve in similar simulations, suggesting redundancy at the genetic level. This model should provide a useful framework to interpret and unify the overly complex observations of evolutionary endocrinology and evolutionary ecology

Teachers’ attitudes towards AI: what is the difference with non-AI technologies?

Educational technologies with AI are designed to personalize students’ learning, but also to alleviate teacher’s workload. However, acceptability of such technologies among teachers may be impacted by factors such as fear of replacement or ethical concerns. The purpose of the current study is to investigate attitudes of teachers towards educational tools with or without AI. The main hypothesis is that technologies with AI would be more negatively judged than technologies without AI, and thus intention to use would be weaker for technologies with AI. Results show that teachers seem to accurately perceive the potential benefit of AI technologies for reduction of workload, without feeling threatened by a replacement in the future. Ethical concerns are higher for AI technologies, but intention to use is similar. Differences between primary and secondary school teachers are discussed

Teachers’ attitudes towards AI: what is the difference with non-AI technologies?

Educational technologies with AI are designed to personalize students' learning, but also to alleviate teacher's workload. However, acceptability of such technologies among teachers may be impacted by factors such as fear of replacement or ethical concerns. The purpose of the current study is to investigate attitudes of teachers towards educational tools with or without AI. The main hypothesis is that technologies with AI would be more negatively judged than technologies without AI, and thus intention to use would be weaker for technologies with AI. Results show that teachers seem to accurately perceive the potential benefit of AI technologies for reduction of workload, without feeling threatened by a replacement in the future. Ethical concerns are higher for AI technologies, but intention to use is similar. Differences between primary and secondary school teachers are discussed

dryad

This directory contains each data files and scripts used for simulations and analysis of Bourg etal 201

Hormonal pleiotropy and the evolution of allocation trade‐offs

International audienc

Teachers’ attitudes towards AI: what is the difference with non-AI technologies?

Educational technologies with AI are designed to personalize students' learning, but also to alleviate teacher's workload. However, acceptability of such technologies among teachers may be impacted by factors such as fear of replacement or ethical concerns. The purpose of the current study is to investigate attitudes of teachers towards educational tools with or without AI. The main hypothesis is that technologies with AI would be more negatively judged than technologies without AI, and thus intention to use would be weaker for technologies with AI. Results show that teachers seem to accurately perceive the potential benefit of AI technologies for reduction of workload, without feeling threatened by a replacement in the future. Ethical concerns are higher for AI technologies, but intention to use is similar. Differences between primary and secondary school teachers are discussed