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Solid Oxide Cell (SOC) technology is considered as an efficient electrolysis technology to produce hydrogen at large scale. It can also operate in fuel cell mode using different fuels (carbon-based or non-carbon based like ammonia), and in reversible mode. Though proofs-of concept have been achieved at different relevant scales for those operating modes, some R&D works still need to be performed to improve performance, durability and cost. Improved and upscaled cells and stacks need to be developed, with a methodology combining multiscale and multiphysics modelling, electrochemical characterization in relevant conditions and advanced post-test analysis. Their integration into modules made of several stacks is also a stepping stone in order to reach multi-MW electrolysers. CEA is working on the whole value chain of SOC technology, from cell development and optimisation to module design and operation through stack upscaling. Recent achievements on those aspects will be presented.

While weight loss is highly recommended for those with obesity, >60% will regain their lost weight. This weight cycling is associated with elevated risk of cardiovascular disease, relative to never having lost weight. How weight loss/regaindirectlyinfluence atherosclerotic inflammation is unknown. Thus, we studied short-term caloric restriction (stCR) in obese hypercholesterolemic mice, without confounding effects from changes in diet composition. Weight loss was found to promote atherosclerosis resolution independent of plasma cholesterol. From single-cell RNA-sequencing and subsequent mechanistic studies, this can be partly attributed to a unique subset of macrophages accumulating with stCR in epididymal adipose tissue (eWAT) and atherosclerotic plaques. These macrophages, distinguished by high expression ofFcgr4, help to clear necrotic cores in atherosclerotic plaques. Conversely, weight regain (WR) following stCR accelerated atherosclerosis progression with disappearance of Fcgr4+ macrophages from eWAT and plaques. Furthermore, WR caused reprogramming of immune progenitors, sustaining hyper-inflammatory responsiveness. In summary, we have developed a model to investigate the inflammatory effects of weight cycling on atherosclerosis and the interplay between adipose tissue, bone marrow, and plaques. The findings suggest potential approaches to promote atherosclerotic plaque resolution in obesity and weight cycling through induction of Fcgr4+ macrophages and inhibition of immune progenitor reprogramming.Graphical abstract

SummaryBackgroundAntimicrobial resistance is a major public health threat, affecting not only humans but also animals and the environment. Although the “One Health” dimension of resistance is well recognized, data are lacking on the circulation of resistance, particularly in low-income countries. The World Health Organization has proposed a protocol called Tricycle, focusing on extended-spectrum beta-lactamase (ESBL)-Escherichia colisurveillance in the three sectors. We implemented Tricycle in Madagascar to assess ESBL-E. coliprevalence and describe intra- and inter-sector circulation of ESBL-E. coliand plasmids.Methods289 pregnant women, 246 farm chickens and 28 surface waters were sampled in Antananarivo (the capital city) area and tested for ESBL-E. coli. Isolates were sequenced by short-(Illumina) and long-(Nanopore) read methods.FindingsESBL-E. coliprevalence was 29·8%, 56·9% and 100% in pregnant women, chickens, and the environment, respectively. The wet season was associated with higher rates of carriage in humans (OR=3·1, 95%CI 1·8-5·3) and animals (OR=2·8 95%CI 1·7-4·8). Sequencing of 277 non-duplicated isolates (82, 118 and 77 from each sector, respectively) showed high genetic diversity (90 STs identified) with differences between sectors. Single nucleotide polymorphism (SNP) analysis revealed 169/277 (61%) isolates grouped into 44 clusters (≥2 isolates) of closely related isolates (blaCTX-M(77.6%blaCTX-M-15), chromosomally integrated in 57·4% (159/277) of isolates, and plasmidic in 40·8% (113/277). The 114 ESBL-carrying plasmids were mainly IncF (55·2%, n=63) and IncY (36·8%, n=42). The F31/36:A4:B1 (n=13) and F-:A-:B53 (n=8) subtypes, and all IncY plasmids, highly conserved, were observed in isolates of differing genetic backgrounds from all sectors.InterpretationDespite varying strain population structures in the three sectors, both ESBL-E. colistrains and plasmids are circulating among humans, chickens and the environment in the capital of Madagascar.FundingFondation Mérieux, INSERM, Université Paris Cité

Metagenomics can be used to monitor the spread of antibiotic resistance genes (ARGs). ARGs found in databases such as ResFinder and CARD primarily originate from culturable and pathogenic bacteria, while ARGs from non-culturable and non-pathogenic bacteria remain understudied. Functional metagenomics is based on phenotypic gene selection and can identify ARGs from non-culturable bacteria with a potentially low identity shared with known ARGs. In 2016, the ResFinderFG v1.0 database was created to collect ARGs from functional metagenomics studies. Here, we present the second version of the database, ResFinderFG v2.0, which is available on the Center of Genomic Epidemiology web server (https://cge.food.dtu.dk/services/ResFinderFG/). It comprises 3,913 ARGs identified by functional metagenomics from 50 carefully curated datasets. We assessed its potential to detect ARGs in comparison to other popular databases in gut, soil and water (marine + freshwater) Global Microbial Gene Catalogues (https://gmgc.embl.de). ResFinderFG v2.0 allowed for the detection of ARGs that were not detected using other databases. These included ARGs conferring resistance to beta-lactams, cycline, phenicol, glycopeptide/cycloserine and trimethoprim/sulfonamide. Thus, ResFinderFG v2.0 can be used to identify ARGs differing from those found in conventional databases and therefore improve the description of resistomes.GRAPHICAL ABSTRACTCaption: Additional use of ResFinderFG v2.0 database (composed of antibiotic resistance genes obtained with functional metagenomics) on the Center of Genomic Epidemiology webserver (https://cge.food.dtu.dk/services/ResFinderFG/), allows for more exhaustive resistome descriptions.

Colistin is an antibiotic of last resort in the management of highly drug-resistant Enterobacterales infections. Travel to some destinations presents a high risk of acquiring multidrug-resistant Enterobacterales, but little data are available on the risk of acquiring colistin-resistant strains. Here, we use the VOYAG-R sample collection (2012-2013) in order to evaluate the rate of acquisition of colistin-resistant Enterobacterales, excluding species with intrinsic resistance (CRE), following travel to tropical regions.A total of 574 frozen stool samples of travellers returning from tropical regions was screened for colistin-resistant strains using ChromID Colistin R agar (bioMerieux®) after pre-enrichment culture with 1 mg/L of colistin. Genomes were obtained by Illumina sequencing and genetic determinants of colistin resistance (mutational events and mcr genes) were searched.A total of 22 travellers (3.8%) acquired colistin-resistant Enterobacterales carrying an mcr gene. Acquisition rates varied between visited regions: 9.2% (18/195) for Asia (Southeast Asia: 17/18), 2.2% (4/184) for Latin America (Peru: 4/4) and 0% from Africa (0/195). Acquired strains were predominantly Escherichia coli (92%) and carried mostly the mcr-1 variant (83%). E. coli strains belonged mainly to commensal phylogroups A and B1, and were genetically highly diverse (5 non-clonal Sequence Type (ST)10 and 17 ST singletons). Only four non mcr colistin-resistant strains (two E. coli and two Enterobacter cloacae complex) were identified. Among all the strains, two also carried extended-spectrum beta-lactamase (ESBL) genes.Travel to tropical regions, and particularly to Southeast Asia, is a risk factor for the acquisition of mcr-carrying Enterobacterales. This study highlights the community dissemination of mcr in humans as early as 2012, 4 years prior to its first published description.

Heightened inflammation in obesity is a major contributor to many diseases, including atherosclerosis and other cardiovascular diseases (CVD). Although weight loss is extremely beneficial in improving many obesity-related conditions, weight regain worsens disease outcomes, including CVD, compared to maintenance of an obese state. Nonetheless, how weight loss promotes inflammation resolution and why weight regain worsens inflammation is poorly understood and was investigated here. Using high-fat high-cholesterol diet feeding of atherogenic mice (Ldlr deficient), we promoted weight loss after the establishment of atherosclerosis and obesity by using dietary restriction, e.g. reducing daily food consumption by 30% for 2 weeks, while maintaining hyperlipidemia. For weight regain, some mice were then given free access to food for 6 weeks. Strikingly, after 2 weeks of dietary restriction we observed atherosclerosis resolution, while weight regain accelerated disease re-progression. Single-cell analysis of visceral adipose and plaque leukocytes revealed enrichment in both tissues of a novel macrophage population with dietary restriction, which is distinguished by high expression of the antibody receptor Fcgr4, a known phagocytosis mediator. Conversely, Fcgr4 + macrophages disappeared from plaques and adipose following weight regain. Mechanistically, Fcgr4 + macrophages from the adipose tissue induced clearance of plaque necrotic core via enhanced efferocytosis. Moreover, we discovered that weight loss and regain differentially influence immune progenitors. Bone marrow (BM) transplantation showed that while weight loss and obese BM recipients had similar plaque inflammation, weight regain BM recipients had larger, more inflammatory plaques. In conclusion, our data are the first to directly show that initial weight loss promotes resolution of atherosclerosis, independently of plasma cholesterol changes and through the enrichment of specialized pro-resolving macrophages in adipose tissue that communicate with plaques. Conversely, weight regain accelerates disease progression via inflammatory reprogramming of immune progenitors.

Characterizing the effect of mutations is key to understand the evolution of protein sequences and to separate neutral amino-acid changes from deleterious ones. Epistatic interactions between residues can lead to a context dependence of mutation effects. Context dependence constrains the amino-acid changes that can contribute to polymorphism in the short term, and the ones that can accumulate between species in the long term. We use computational approaches to accurately predict the polymorphisms segregating in a panel of 61,157 Escherichia coli genomes from the analysis of distant homologues. By comparing a context-aware Direct-Coupling Analysis modelling to a non-epistatic approach, we show that the genetic context strongly constrains the tolerable amino acids in 30% to 50% of amino-acid sites. The study of more distant species suggests the gradual build-up of genetic context over long evolutionary timescales by the accumulation of small epistatic contributions.

Escherichia coli is a ubiquitous bacterium that has been widely exposed to antibiotics over the last 70 years. It has adapted by acquiring different antibiotic-resistance genes (ARGs), the census of which we aim to characterize here. To do so, we analysed 70 301 E. coli genomes obtained from the EnteroBase database and detected 1 027 651 ARGs using the AMRFinder, Mustard and ResfinderFG ARG databases. We observed a strong phylogroup and clonal lineage specific distribution of some ARGs, supporting the argument for epistasis between ARGs and the strain genetic background. However, each phylogroup had ARGs conferring a similar antibiotic class resistance pattern, indicating phenotypic adaptive convergence. The G+C content or the type of ARG was not associated with the frequency of the ARG in the database. In addition, we identified ARGs from anaerobic, non- Proteobacteria bacteria in four genomes of E. coli , supporting the hypothesis that the transfer between anaerobic bacteria and E. coli can spontaneously occur but remains exceptional. In conclusion, we showed that phylum barrier and intra-species phylogenetic history are major drivers of the acquisition of a resistome in E. coli .

Travel to tropical regions is associated with high risk of acquiring extended-spectrum beta-lactamase-producing Enterobacterales (ESBL-E) that are typically cleared in less than 3 months following return. The conditions leading to persistent carriage that exceeds 3 months in some travellers require investigation. Whole-genome sequencing (Illumina MiSeq) was performed on the 82 ESBL-E isolates detected upon return and 1, 2, 3, 6 and 12 months later from the stools of 11 long-term (>3 months) ESBL-E carriers following travel abroad. One to five different ESBL Escherichia coli strains were detected per traveller upon return, and this diminished to one after 3 months. Long-term carriage was due to the presence of the same ESBL E. coli strain, for more than 3 months, in 9 out of 11 travellers, belonging to epidemic sequence type complexes (STc 10, 14, 38, 69, 131 and 648). The mean carriage duration of strains belonging to phylogroups B2/D/F, associated with extra-intestinal virulence, was higher than that for commensal-associated A/B1/E phylogroups (3.5 vs 0.5 months, P=0.021). Genes encoding iron capture systems (fyuA, irp), toxins (senB, sat), adhesins (flu, daaF, afa/nfaE, pap, ecpA) and colicin (cjrA) were more often present in persistent strains than in transient ones. Single-nucleotide polymorphism (SNP) analysis in persistent strains showed a maximum divergence of eight SNPs over 12 months without signs of adaptation. Genomic plasticity was observed during the follow-up with the loss or gain of mobile genetic elements such as plasmids, integrons and/or transposons that may contain resistance genes at different points in the follow-up. Long-term colonization of ESBL-E following travel is primarily due to the acquisition of E. coli strains belonging to epidemic clones and harbouring ‘virulence genes’, allowing good adaptation to the intestinal microbiota.

Dans l’optique d’un panorama des publications accessibles au lectorat des enseignants et des chercheurs en matiere d’enseignement de la lecture, cette etude examine quelle part revient au livre jeunesse dans la litterature didactique sur l’enseignement-apprentissage de la lecture, a travers la mention explicite d’ouvrages. Le releve des articles concerne trois revues (Carrefours de l’education, Le francais aujourd’hui et Reperes) entre 2001 et 2017. L’examen des articles retenus est mis en correlation avec un premier tableau du developpement de la recherche en litterature de jeunesse, permettant d’interroger l’incidence sur le champ didactique de facteurs croises, pedagogiques mais aussi institutionnels et editoriaux, ainsi que du role joue par les differents partenaires du livre jeunesse pour la promotion de la lecture. Les resultats permettent de conclure au traitement different du livre jeunesse selon les revues, leur discipline d’origine et leurs enjeux scientifiques. Ils ne confortent pas l’idee d’un effacement contemporain des problematiques liees au livre, selon une periodisation qui serait dependante des programmes scolaires de l’elementaire.

The biological features that allow a pathogen to survive in the hospital environment are mostly unknown. The extinction of bacterial epidemics in hospitals is mostly attributed to changes in medical practice, including infection control, but the role of bacterial adaptation has never been documented. We analysed a collection of Pseudomonas aeruginosa isolates belonging to the Besançon Epidemic Strain (BES), responsible for a 12year nosocomial outbreak, using a genotype-to-phenotype approach. Bayesian analysis estimated the emergence of the clone in the hospital 5 years before its opening, during the creation of its water distribution network made of copper. BES survived better than the reference strains PAO1 and PA14 in a copper solution due to a genomic island containing 13 metal-resistance genes and was specifically able to proliferate in the ubiquitous amoeba Vermamoeba vermiformis. Mutations affecting amino-acid metabolism, antibiotic resistance, lipopolysaccharide biosynthesis, and regulation were enriched during the spread of BES. Seven distinct regulatory mutations attenuated the overexpression of the genes encoding the efflux pump MexAB-OprM over time. The fitness of BES decreased over time in correlation with its genome size. Overall, the resistance to inhibitors and predators presumably aided the proliferation and propagation of BES in the plumbing system of the hospital. The pathogen further spread among patients via multiple routes of contamination. The decreased prevalence of patients infected by BES mirrored the parallel and convergent genomic evolution and reduction that affected bacterial fitness. Along with infection control measures, this may have participated in the extinction of BES in the hospital setting.

International audience

Escherichia coli is a ubiquitous bacterium that has widely been exposed to antibiotics over the last 70 years. It has adapted by acquiring different antibiotic resistance genes (ARG), which we aim at characterizing the census here. To do so, we analysed 70,301 E. coli genomes obtained from the EnteroBase database and detected 1,027,651 ARG using the AMRFinder, Mustard and ResfinderFG ARG databases. We observed a strong phylogroup/clonal lineage specific distribution of some ARG, arguing for epistasis between ARG and the strain genetic background. However, each phylogroup had ARG conferring a similar resistance pattern, indicating phenotypic convergence. The GC content or the type of ARG was not associated to the frequency of the ARG in the database. Besides, we identified ARG from anaerobic, non-Proteobacteria bacteria in four genomes of E. coli supporting that the transfer between anaerobic bacteria and E. coli can spontaneously occur but remain exceptional. In conclusion, we showed that phylum barrier and intra-species phylogenetic history are major drivers of the acquisition of resistome in E. coli.

The biological features that allow a pathogen to survive in the hospital environment are mostly unknown. The extinction of bacterial epidemics in hospitals is mostly attributed to changes in medical practice, including infection control, but the role of bacterial adaptation has never been documented. We analyzed a collection of Pseudomonas aeruginosa isolates belonging to the Besançon Epidemic Strain (BES), responsible for a 12-year nosocomial outbreak, using a genotype-to-phenotype approach. Bayesian analysis estimated the emergence of the clone in the hospital five years before its opening, during the creation of its water distribution network made of copper. BES survived better than the reference strains PAO1 and PA14 in a copper solution due to a genomic island containing 13 metal-resistance genes and was specifically able to proliferate in the ubiquitous amoeba Vermamoeba vermiformis. Mutations affecting amino-acid metabolism, antibiotic resistance, lipopolysaccharide biosynthesis, and regulation were enriched during the spread of BES. Seven distinct regulatory mutations attenuated the overexpression of the genes encoding the efflux pump MexAB-OprM over time. The fitness of BES decreased over time in correlation with its genome size. Overall, the resistance to inhibitors and predators presumably aided the proliferation and propagation of BES in the plumbing system of the hospital. The pathogen further spread among patients via multiple routes of contamination. The decreased prevalence of patients infected by BES mirrored the parallel and convergent genomic evolution and reduction that affected bacterial fitness. Along with infection control measures, this may have participated in the extinction of BES in the hospital setting.ImportanceBacterial pathogens are responsible for nosocomial outbreaks, but the sources of contamination of the hospitals are mostly unclear and the role of bacterial evolution in the extinction of outbreaks has never been considered. Here, we found that an epidemic strain of the pathogen Pseudomonas aeruginosa contaminated the drinking water network of a hospital due to its tolerance to copper and predatory amoeba, both present in the water pipes. The extinction of the outbreak occurred concomitantly with parallel and convergent genome evolution and a reduction in the size of the bacterial genome that correlated with the fitness of the pathogen. Our data suggest that pathogen evolution participated in the extinction of an outbreak in a hospital setting.

Pour éclairer le choix qui se pose au professeur de littérature entre un cours dédié au numérique et un cours intégrant le numérique comme un des paramètres de son enseignement, l’étude propose trois approches successives : par les objets d’enseignement, par les usages en formation, par le recueil de représentations.Si l’intégration d’oeuvres numériques au cours de littérature s’envisage aisément dans une perspective d’histoire littéraire aussi bien que dans celle d’une lecture analytique (Bootz, 2019; Dall’Armellina, 2015; Petitjean et Brunel, 2018), le regard porté sur des expériences menées en formation amène à percevoir beaucoup plus radicalement les perturbations engendrées par le numérique sur les repères distinctifs de l’oeuvre, de la littérarité ou de l’auteur singulier (Bouchardon, 2014; Gefen, 2012; Saemmer, 2018). Le déplacement de l’attention vers l’intérieur des processus de création, favorisé par les usages de la production numérique et renvoyant à un principe d’apprentissage littéraire par l’expérimentation (Dewey, 1934), sollicite le déploiement d’une armature didactique qui n’ignore pas les spécificités de l’écriture sur écran (Lacelle et al., 2017; Petitjean et al., 2017). Pour documenter ce troisième plan, deux enquêtes ont été menées en parallèle auprès d’enseignants (75 répondants) et auprès d’écrivains et apprentis écrivains (90 répondants). Leur analyse comparée met en évidence un certain nombre de clivages entre les représentations et les pratiques effectives, mais également une appétence des enseignants pour une meilleure connaissance des mutations des pratiques rédactionnelles des écrivains.L’étude est menée avec le concours du groupe de recherche « Écriture créative en formations : enjeux épistémologiques et méthodologies de recherche » de l’Initiative d’excellence Paris Seine., In order to clarify the choice for the professor of literature between a course dedicated to digital works and a course integrating digital as one of the parameters of literary education, this study suggests three successive approaches: digital works as teaching material, uses in digital literary training and a survey of representations.If the integration of digital works in literature courses can be considered in a perspective of literary history, it can also focus on an analytical reading without disturbing so much the actions of teachers. By contrast, much more radical disturbances on the distinctive landmarks of creative works, literality or the concept of literarity (Gefen 2012; Bouchardon 2014; Saemmer 2018) can be seen in teaching experiences with digital creative writing. Digital uses in teacher’s classes in accordance with Dewey’s theory of aesthetic experience (1934) call for focusing the attention towards the interior of the creative process. It also calls for the deployment of a didactic framework which is aware of the characteristics of digital writing (Lacelle, Boutin, Lebrun 2017; Petitjean, Cordier, Alamargot 2017). To investigate the representations used in conceiving such a didactic approach, two surveys were conducted in parallel: one with teachers (75 respondents) and another one with writers and apprentice writers (90 respondents). Their comparative analysis highlights some discrepancies between representations and actual digital practices but also brings to light the teachers’ wish to better understand how digital practices change the creative writing practices of writers.Our study is supported by the research group "Creative writing in training: epistemological issues and research methodologies" of the Paris Seine Excellence Initiative.

La question du passage à l’écriture s’avère peu traitée dans les travaux actuels sur le décrochage scolaire alors même que les enseignants des microlycées d’Évreux et de Paris ont une demande explicite concernant les difficultés que rencontrent leurs élèves pour passer à l’écriture académique, en même temps d’ailleurs qu’ils soulignent leurs compétences en écriture créative. Pour répondre à cette demande, l’étude diagnostique que nous présentons s’appuie sur des données diverses : observations, enquêtes auprès des acteurs, textes produits lors d’une séance d’écriture créative. Cet ensemble est construit à partir de positions théoriques sociolinguistiques et (socio)didactiques qui seront rappelées. Il nous amène à mettre en évidence l’existence effective de compétences en écriture créative chez les élèves du microlycée et à en évaluer les enjeux pour la didactique. Although the issue of writing has, to date, been accorded only scant attention in publications on the school drop-out issue, two ‘micro-lycées’(secondary schools for former dropouts) in Evreux and Paris have identified students’ difficulties in academic writing, in con-trast to their good creative writing skills. To address this gap, the following diagnostic study examines various data: classroom ob-servations, surveys among school partners and draft texts from a creative writing workshop. The study is based on sociolinguistic and (socio)didactic theories which are set out in it. It enables us to highlight the very real creative writing skills developed by these former dropouts and to evaluate the didactic issues at stake.

When bacterial lineages make the transition from free-living to permanent association with hosts, they can undergo massive gene losses, for which the selective forces within host tissues are unknown. We identified here melanogenic clinical isolates of Pseudomonas aeruginosa with large chromosomal deletions (66 to 270 kbp) and characterized them to investigate how they were selected. When compared with their wild-type parents, melanogenic mutants (i) exhibited a lower fitness in growth conditions found in human tissues, such as hyperosmolarity and presence of aminoglycoside antibiotics, (ii) narrowed their metabolic spectrum with a growth disadvantage with particular carbon sources, including aromatic amino acids and acyclic terpenes, suggesting a reduction of metabolic flexibility. Despite an impaired fitness in rich media, melanogenic mutants can inhibit their wild-type parents and compete with them in coculture. Surprisingly, melanogenic mutants became highly resistant to two intraspecific toxins, the S-pyocins AP41 and S1. Our results suggest that pyocins produced within a population of infecting P. aeruginosa may have selected for bacterial mutants that underwent massive gene losses and that were adapted to the life in diverse bacterial communities in the human host. Intraspecific interactions may therefore be an important factor driving the continuing evolution of pathogens during host infections.

OBJECTIVES The objective of this study was to characterize ESBL-producing Enterobacter cloacae isolated from animals and to compare their clonal distribution with that of human-related isolates. METHODS Among 635 clinical E. cloacae from horses, dogs and cats collected in France between 2010 and 2013, 36 were resistant to ceftiofur as determined by disc diffusion. ESBL genes were identified by sequencing. Plasmids carrying ESBL-encoding genes were characterized by PCR-based replicon typing, S1-PFGE and Southern blotting. IncHI2 plasmids were subtyped using the plasmid double-locus sequence typing scheme and multiplex amplification of the hipA, smr0092 and smr0183 genes. All E. cloacae were typed by PFGE and MLST. ST clustering was analysed by eBURST. RESULTS All 36 ceftiofur-resistant E. cloacae produced an ESBL. Their PFGE patterns formed 23 clusters of high similarity and 13 STs and were isolated from epidemiologically unrelated animals (14 horses, 11 dogs and 11 cats) distributed throughout France. ST114, the most prevalent clone in humans, was over-represented in animals (16/36) compared with other human-related clones detected here. The blaCTX-M-15 gene was dominant (66.7%) and mostly carried on IncHI2 plasmids (ST1 subtype). ST114 isolates always produced CTX-M-15. CONCLUSIONS Most ESBL-producing E. cloacae from animals studied here (69.4%) belonged to potentially high-risk clones in humans, in particular ST114 (44.4%). These data raise questions and potential concerns about the transfer of E. cloacae between animals and humans.

International audience

Dans le cadre des formations en ecriture creative, Virginie Gautier et Francois Bon temoignent de la maniere dont ils initient les etudiants de Cergy-Pontoise au role que joue actuellement le numerique dans les processus de creation litteraire. Leurs temoignages, d’abord recueillis a partir d’une serie de questions, sont rapportes dans un propos thematique qui permet de rendre compte des points de tension qui emergent quand le numerique est saisi plutot comme une force adventice ou comme un environnement favorisant la creativite et l’exposition du travail de l’ecrivain. Le trajet invite a quitter l’idee d’une incidence du numerique sur le litteraire pour mesurer des zones de convergence qui en appellent a un espace commun generatif qui puisse etre enseigne comme tel.

High Temperature Steam Electrolysis (HTSE), based on solid oxide electrolysis cells (SOE) is a promising way to produce massively hydrogen with high efficiencies. This technology also allows producing syngas (H 2 + CO) by co-electrolyzing a mix of steam and CO 2 . This syngas constitutes the basis to obtain further synthetic fuels. For both HTSE and co-electrolysis, durability and cost are still key points, but additionally for co-electrolysis the outlet H 2 /CO gas composition has to be tailored to fit with the targeted fuels. Previous works have been carried out to develop a stack design suitable for both applications. Here experiments at stack level in both electrolysis and co-electrolysis modes have been carried out. A 10-cell stack and a 25-cell stack have been tested in electrolysis mode, respectively producing 0.6 Nm 3 /h and 1.7 Nm 3 /h of hydrogen at 800 °C below the thermoneutral voltage (1.3 V) for all the cells and a steam conversion around 50%, with a small scattering between the different cells. Gas tightness of the stacks has also been evaluated. Moreover, the operation in co-electrolysis has been validated. Finally a cost analysis of this stack design has been performed and shows all the economical potentialities of this technology.

International audience; Pseudomonas aeruginosa is a ubiquitous opportunistic pathogen with several clones being frequently associated with outbreaks in hospital settings. ST395 is among these so-called 'international' clones. We aimed here to define the biological features that could have helped the implantation and spread of the clone ST395 in hospital settings. The complete genome of a multidrug resistant index isolate (DHS01) of a large hospital outbreak was analysed. We identified DHS01-specific genetic elements, among which were identified those shared with a panel of six independent ST395 isolates responsible for outbreaks in other hospitals. DHS01 has the fifth largest chromosome of the species (7.1 Mbp), with most of its 1555 accessory genes borne by either genomic islands (GIs, n=48) or integrative and conjugative elements (ICEs, n=5). DHS01 is multidrug resistant mostly due to chromosomal mutations. It displayed signatures of adaptation to chronic infection in part due to the loss of a 131 kbp chromosomal fragment. Four GIs were specific to the clone ST395 and contained genes involved in metabolism (GI-4), in virulence (GI-6) and in resistance to copper (GI-7). GI-7 harboured an array of six copper transporters and was shared with non-pathogenic Pseudomonas sp. retrieved from copper-contaminated environments. Copper resistance was confirmed phenotypically in all other ST395 isolates and possibly accounted for the spreading capability of the clone in hospital outbreaks, where water networks have been incriminated. This suggests that genes transferred from copper-polluted environments may have favoured the implantation and spread of the international clone P. aeruginosa ST395 in hospital settings.

This work details an in-house 2D electrochemical and thermal model of solid oxide electrolysis cell (SOEC) dedicated to the simultaneous electrolysis of steam and carbon dioxide. The apparent exchange current densities for both H2O and CO2 electrochemical reductions have been fitted on single electrolysis polarization curves obtained on a standard cathode supported cell (CSC). By using these values, predictive simulations have been performed in a co-electrolysis mode. The results have been compared to experimental data obtained in the same conditions. A good agreement is found between the simulated points and the experimental polarization curves, meaning that the model stands to predict accurately the SOEC response in co-electrolysis mode. Simulations have been performed to investigate co-electrolysis mechanisms in terms of partial pressures, current densities, and overpotentials distributions along the cell. The relative influence of both water gas shift (WGS) reaction and CO2 electrolysis on the global CO production is also discussed.

The main challenges for High Temperature Steam Electrolysis (HTSE) to become competitive towards other hydrogen production technologies are the increase of performance and durability and the decrease of cost. For that purpose, a “low-weight” stack has been designed, including advanced cells and stack components. A performance of -1.9 A.cm-2 at the thermoneutral voltage of 1.3 V has been obtained at 800°C at the scale of a 3-cell stack and its robustness upon thermal cycling has been validated. The upscaling of the technology has been checked with a stack of 10 cells that allowed producing 0.9 Nm3.h-1 of hydrogen. Techno-economical analysis showed that this low-weight design led to a considerable decrease of the stack cost.

L’analyse de seances d’ecriture sur la ponctuation dans un parcours de lettres s’inscrit dans le cadre general d’une reflexion sur les pratiques d’ecriture creative a l’universite. Quelques jalons permettent d’abord d’identifier une synergie nouvelle a l’œuvre quand il est question de formation a l’ecriture dans les parcours litteraires. Pour mesurer l’evolution des pratiques francaises sont avances en particulier des elements de comparaison internationale. L’experience des ateliers d’ecriture de licence a l’universite est ensuite presentee a travers des textes d’etudiants qui permettent d’aborder les questions de la perception de la norme, de l’apprehension du texte d’auteur et de l’appropriation d’une contrainte formelle. Enfin, l’evaluation est envisagee comme pierre angulaire d’une demarche construisant un rapport artistique a la langue, a la fois outil rhetorique et objet d’experimentation creative.

International audience; High-temperature electrolysis (HTSE) is a quite recent topic where most of the studies are focused on performance measurements and degradation observations, mainly achieved by polarization curve. However, it mainly leads to the overall cell behaviour. To get more specific knowledge on the operation of the cell, Electrochemical Impedance Spectroscopy (EIS) is more appropriate. In this study, EIS and chronopotentiometry were combined in order to characterize the electrochemical performance and behaviour of a commercial electrode-supported cell of Ni-YSZ/YSZ/LSCF type. A two-electrode configuration was used while a three-electrode one is required to better separate each component behavior. Nevertheless, it allows applying EIS to any single cell mainly when no good location for a reference electrode is available. Experimental parameters such as current density, temperature or PH2O/PH2 ratio were analysed. Using electrical equivalent circuit (EEC) combined to the distribution of relaxation time (DRT) and the analysis of the difference in impedance spectra (ADIS) approaches allowed deconvoluting impedance diagrams into three or four arcs characterized by their specific capacitance and relaxation frequency. Each arc was ascribed to a phenomenon related to the electrochemical reactions. This work corresponds to an in situ diagnosis by EIS of solid oxide electrolyser cell reaction mechanisms.

International audience

Nous poursuivons une première étude menée auprès de lycéens raccrocheurs, en interrogeant cette fois les distinctions de genre dans l’identification de compétences littéraciques en production. Le recueil de données associe discours — des élèves, des enseignants, de l’écrivain en résidence — et pratiques rédactionnelles, selon des dispositifs comparés qui font ou non intervenir le numérique.L’étude, qui mobilise un arrière-plan théorique élaboré au fil de travaux antérieurs, met en évidence chez ces élèves un rapport à l’écriture qui bénéficie du « déjà-là » de pratiques non scolaires. Les stéréotypes filles/garçons dans les représentations et les textes produits se révèlent bien moins présents dans les dispositifs scolaires sollicitant une écriture créative que dans ceux qui se rapprochent de l’opération de lecture demandée dans les écrits académiques., This study extends a first analysis of high literacy skills in written works produced by former dropouts in a secondary school in Paris. The question of gender division is discussed through a collection of data including students and teachers’ talks, a writer-in-residence interview, and written materials, some using digital tools. Theoretical grounding informs the recognition of an approach to writing, supported by informal practices including digital usages. Results suggest that gender stereotypes in discourses and writing practices are less found in texts produced during creative writing workshops than in texts explicitly related to academic works.

A new stack designed for High Temperature Steam Electrolysis is presented here. It integrates grids as contact layers and an optimized sealing solution. The design has first been validated at the SRU level before operating a 5-cell stack for a performance and durability test. Performance results show that i-V curves at the SRU and stack level are very close to those obtained at the single cell level, highlighting an optimized design and more specifically good contacts between the interconnects and the cells. Very high performances have been obtained (-1 A/cm² at 1.2-1.3 V at 800°C) at the stack level and more than 99% of the produced hydrogen has been collected. A durability test of 2700 hours has been carried out with a current density of -0.5 A/cm² and a steam conversion rate of 25%. Degradation rates around 7-13 %/kh for the 3 central cells have been measured during this test.

This work concerns the feasibility of SOFC operation directly on biogas and more specifically, the optimization of biogas internal dry reforming conditions. A special attention is paid to the carbon deposition risk. For such a purpose simulation tools have been developed, based on thermodynamic and electrochemical modelling, in order to determine the risk of carbon formation within the anode during operation. Safe operation conditions in terms of temperature, fuel composition and cell polarization have been established and validated experimentally. In conditions where carbon deposition is expected, performance degradation upon operation has been followed over more than hundred hours on complete cells (Cermet Ni-8YSZ//8YSZ//LSM) by electrochemical impedance spectroscopy. The carbon deposited has been characterized by scanning electron microscopy with particular attention given to its morphology and distribution.

L’émergence d’une littérature numérique pour le jeune public a encore été peu analysée sur un plan littéraire. L’émergence de nouveaux formats s’écartant de l’imitation de l’album ou du livre illustré peut pourtant déstabiliser les repères habituels d’une éducation à la lecture par fréquentation de l’objet livre. Pour envisager ce que la prise en compte des possibilités technologiques transforme effectivement dans l’acte de lecture et l’implication du jeune lecteur, cinq applications pour le jeune public, primées ou reconnues par la communauté professionnelle, sont passées au crible d’une analyse, attentive autant aux bouleversements qu’aux filiations identifiables pour tous les amateurs de littérature jeunesse papier. The emergence of digital children’s literature has not yet been analyzed from a literary point of view. The emergence of new formats that depart from picture book and illustrated book imitation can however destabilize typical educational reference points made through reading physical books. In order to consider what aspects within technological possibilities are actually transformed in the act of reading, five applications for a young audience, awarded or recognized by the professional community, are analyzed here with the young reader’s involvement, giving as much attention to the changes as to identifiable connections these amateurs of hardcopy children's literature might make.

International audience; During evolution of microorganisms genomes underwork have different changes in their lengths, gene orders, and gene contents. Investigating these structural rearrangements helps to understand how genomes have been modified over time. Some elements that play an important role in genome rearrangements are called insertion sequences (ISs), they are the simplest types of transposable elements (TEs) that widely spread within prokaryotic genomes. ISs can be defined as DNA segments that have the ability to move (cut and paste) themselves to another location within the same chromosome or not. Due to their ability to move around, they are often presented as responsible of some of these genomic recombination. Authors of this research work have regarded this claim, by checking if a relation between insertion sequences (ISs) and genome rearrangements can be found. To achieve this goal, a new pipeline that combines various tools has firstly been designed, for detecting the distribution of ORFs that belongs to each IS category. Secondly, links between these predicted ISs and observed rearrangements of two close genomes have been investigated, by seeing them with the naked eye, and by using computational approaches. The proposal has been tested on 18 complete bacterial genomes of Pseudomonas aeruginosa, leading to the conclusion that IS3 family of insertion sequences are related to genomic inversions.

(La 0.8 Sr 0.2 )(Mn 1 − y Fe y )O 3 ± δ films with y = 0, 0.2, 0.5, 0.8 and 1, a few hundred nanometers thick, were deposited onto polycrystalline yttria-stabilized zirconia YSZ by a magnetron co-sputtering technique using individual targets of La 0.8 Sr 0.2 MnO 3 and La 0.8 Sr 0.2 FeO 3 . The deposition parameters, substrate temperature and gas pressure, were studied by scanning electron microscopy, energy dispersive X-ray spectrometry, X-ray diffraction and interferential microscopy for their effects on the morphological, chemical, topographic and crystallographic properties of films and YSZ-film interfaces. (La 0.8 Sr 0.2 )(Mn 1 − y Fe y )O 3 ± δ thin films were found to be homogeneous, dense and crystallized in the perovskite structure after deposition at 600 °C. Profilometry by secondary ion mass spectrometry and observations by Auger electron spectrometry after selective dissolution of the films were also used to investigate both morphology and quality of the YSZ-film interface after deposition.

The oxygen transport properties in (La 0.8 Sr 0.2 )(Mn 1-y Fe y )O 3±δ (LSMF) with various iron contents y = 0, 0.2, 0.5, 0.8 and 1 were determined by the IEDP technique. Both oxygen diffusion and surface exchange coefficients were found to be greater for y = 0.8 and 1 than those of LSM (y=0). Moreover, for y ≤0.5, grain boundary diffusion was the rate limiting step especially at lower temperatures. Thus, in the LSMF perovskite materials, the oxygen diffusion via oxygen vacancies is enhanced by Fe. The LSMF electrical performances were measured by impedance spectroscopy. Compared to LSM and LSF (y= 1), porous LSMF cathodes with y= 0.2-0.8 exhibit poor electronic conductivity: Fe, by reducing the number of couples Mn 3+ /Mn 4+ , decreases the amount of available hopping sites, limiting the electrical conduction. For LSF, the charge disproportionation Fe 3+ /Fe 5+ improves the electrical properties. In conclusion, only the LSMF compounds with y ∼ 1 or 0 can be considered as good cathode materials for SOFC applications.

Solid Oxide Electrolysis (SOE) technology is considered to be a highly efficient process to produce hydrogen. It is liable to produce hydrogen at low cost, thanks to an electrical consumption as low as 3.5 kWh per Nm3of hydrogen produced, considering a heat source available to produce steam around 150°C. A smart heat management into the SOE system needs to be found to heat this steam at 150°C up to the operating temperature of the SOE which is in the range of 700-800°C. Therefore it appears that the steam conversion rate is a key parameter in the overall efficiency of the system. Most generally, due to concentration overpotentials leading to a limiting current at the cell level, to which a non-homogeneous distribution of gases into the stack can be added, steam conversion rates of 50% or below are reported. Then large flows of steam need to be overheated up to the operating temperature, which impacts the overall efficiency of the system. The present paper presents the methodology undertaken to develop a stack design able to operate at high steam conversion rates (80% or above). Starting from a reference stack design made of 25 cathode supported cells and ferritic stainless steel interconnects, modifications of the design have been made to improve the gas distribution to the cells and its homogeneity in the stack. This improvement has first been validated at the scale of a SRU (single repeat unit, the cell active area being equal to 100 cm²). I-V curves have been recorded at 800°C, with a cathodic inlet flow constituted of 90%H2O/10%H2and an anodic flow made of air, the total cathodic flow rate varying between 9 and 30 NmL/min/cm². It has been shown that with these design modifications, i-V curves can be recorded up to a steam conversion rate of 100%. For an inlet flow rate very low, equal to 9 Nml/min/cm², the 100% of steam conversion rate is reached for a current density of 1.15 A/cm² at 1.23V (figure 1). For an inlet flow rate of 12 Nml/min/cm², the 100% of steam conversion rate is reached for a higher current density of 1.56 A/cm² at 1.40V. In both cases, a limiting current appeared only far on the curve, for a current density of 1.06 A/cm² in the first case and 1.45 A/cm² in the second case. I-V curves have been plotted with several other inlet flow rates, and it has been shown that the lower is the inlet flow rate, the higher is the maximum steam conversion rate. However, even for the highest flow rates tested (24 and 30 NmL/min/cm²), the maximum reachable steam conversion rates remain respectively at values of 90 and 80%. These results validate the design modification, which was then implemented at the scale of a 25-cell stack. The reference stack design, prior any modification, reaches, at 800°C, a current density of 0.85 A/cm² at 1.2V in average per cell, for a steam conversion rate of 55% and a corresponding inlet flow rate of 12 NmL/min/cm². For this value of steam conversion rate, a limiting current starts to appear. On the contrary, with the design modification, no limiting current appeared on the i-V curve. For the highest current density recorded, equal to 1.0 A/cm², corresponding to an voltage of 1.17 V/cell, the steam conversion rate was of 64% with a corresponding inlet flow rate of 12 NmL/min/cm². Therefore it can be concluded that thanks to the design modifications, the limiting current is shifted to values well above 65%, and that the stack can be operated at high steam conversion rate. Several 25-cell stacks have been produced with either the reference design or the modified design. With the reference stacks, the voltage scattering among the 25 cells of the stack is around 15%, which is acceptable. Thanks to the design modification, the scattering decreases to a value around 5%. It shows that the design modification not only allows to reach higher steam conversion rates, but also improves the gas distribution homogeneity into the stack. Finally, a 25-cell stack with the modified design has been integrated into a SOE system including all BoP components. It has been possible to operate this stack, at the system level, up to a value of steam conversion of 80%. Figure 1

Introduction The integration of renewable energies to the global energy market implies electricity storage. However, the available technologies for electricity storage have a low energy capacity and a short time-span. In this context, H2 or carbon molecules produced via water and/or water+CO2 electrolysis open up excellent perspectives for storing renewable electricity, especially the High Temperature Electrolysis (HTE). This technology, based on Solid Oxide Cell (SOC), consumes less electrical energy than low temperature electrolysis because of the energy demand is significantly lowered by the vaporization of water1. The required electrical power is also reduced at high temperature since the steam electrolysis is increasingly endothermic with temperature. Moreover HTE can also directly convert a mix of water and CO2 into syngas, (CO+H2) (co-electrolysis), which can be converted into methane or other hydrocarbon molecules. Moreover, this type of co-electrolyzer can operate under pressure which increases the energy efficiency of the system, reducing the compression costs of the downstream chemical processing unit and increasing cells performance.2 In addition, as nickel present in SOC is known to catalyze CO and CO2 (COx) methanation and water gas shift reactions3, a pressure increase in the electrolyser leads to higher rates of these reactions. HTE cells can also be used in fuel cell mode to generate electricity from methane and water4. In this case, nickel catalyzes steam reforming leading to syngas which can be used to produce electricity. However, the contribution of these catalytic reactions are not well-known in co-electrolysis and fuel cell modes. In this view, we propose to evaluate their impact in a SOC fed with carbonated gases by establishing a kinetic model necessary for a complete electrochemical SOC modelling. This work was carried out on two different SOCs to establish kinetic models for co-electrolysis and steam reforming at atmospheric pressure and then under pressure. Catalytic tests The cells studied come from two different suppliers (A and B). In order to study the catalytic reactions, induced by nickel in the hydrogen electrode, other layers have been removed by sandblasting. COX methanation catalytic tests were performed at 400°C with the cells reduced into powder with different inlet mixtures (CO and/or CO2 with H2 with COx/H2 molar ratio around 0.3). Tests were carried out with a total flow rate of 35NmL.min-1 (equivalent to 346NmL.min-1.cm-2 cell and 245NmL.min-1.cm-2 cell for cells A and B, respectively). These flowrates are far from those commonly used for electrochemical tests, but they allow to distinguish the catalytic activity of the two cells. The results showed that cells are not equivalent to each other regarding COx conversion whatever the conditions used (CO and/or CO2) (Figure 1). It also can be noticed that the CO2 hydrogenation activity is reduced after exposure to a CO/H2mixture (Figure. 2) due to carbon deposition blocking the active sites. Secondly, catalytic tests were achieved to demonstrate the influence of water at the inlet (up to 15mol.% of water). The temperature was varied from 400 to 800°C after initial stabilization at 400°C. These tests confirmed the negative effect of water due to a less favorable thermodynamic. Finally, methane steam reforming catalytic tests were carried out to simulate fuel cell feeding conditions (H2O/CH4 molar ratio around 2) with a total flow rate of 5.3NmL.min-1 (equivalent to 52NmL.min-1/cm-2 cell and 37NmL.min-1.cm-2 cell for cells A and B, respectively). These conditions make it possible to approach the operating conditions of an electrolyser. The temperature was varied from 600 to 800°C after initial stabilization at 600°C. It appears that the A cell is close to thermodynamic equilibrium up to 700°C followed by a decrease at higher temperature whereas the B cell does not exhibit this decrease (Figure 5). Conclusions and outlooks The cells exhibit similar catalytic activities with respect to COX methanation and methane reforming. Simulations carried out using the COMSOL software allowed to select three kinetic models for atmospheric SOC operation5 , 6. To discriminate these models and propose a quantitative kinetic model for the SOCs operating under pressure, catalytic and electrochemical tests will be carried out up to 15 bars. Simulations will then be performed (COSMOL) to simulate the functioning of a cell by coupling catalysis, electrochemistry, gaseous and thermal flows. 1. Ni M. et al. Int. J. Hydrogen Energy 33,2337–2354 (2008). 2. Bernadet L. et al. Int. J. Hydrogen Energy 40,12918–12928 (2015). 3. Gao J. et al. RSC Adv. 5,22759–22776 (2015). 4. Er-rbib H. et al. Energy 75,81–88 (2014). 5. Wang Y. et al. Int. J. Hydrogen Energy 34,3885–3893 (2009). 6. Peters R. et al. J. Power Sources 106, 238–244 (2002). Figure 1

International audience; The present study is focused on alternative structured oxygen electrodes for solid oxide electrolysis cells (SOEC). The Ln2NiO4+δ (Ln = La or Pr) nickelate oxides were selected as innovative electrode materials with respect to their mixed electronic and ionic conductivity. A thin interfacial ceria-based layer was added in between the electrode and the zirconia-based electrolyte to improve mechanical and electrochemical properties and to limit the chemical reactivity. These structured cells were characterized by electrochemical impedance spectroscopy on symmetrical cells, under zero dc conditions and anodic polarization. Low polarization resistance RP and improved anodic overpotential ηA versus current density curves were obtained for the Pr2NiO4+δ electrode with Ce0.8Y0.2O2-δ interlayer: RP is decreased down to 0.06 Ω cm2 at 800 °C, under air and zero dc conditions. Then, complete hydrogen electrode-supported cells including Pr2NiO4+δ as oxygen electrode were electrochemically characterized. At 800 °C, when the inlet gas composition is 90 vol.% H2O-10 vol.% H2 at the hydrogen electrode, air being swept at the oxygen electrode, the current density determined at 1.28 V reaches -0.9 A cm-2, the corresponding steam to hydrogen conversion ratio being 58%. These results are compared to those obtained with a reference cell including the oxygen deficient perovskite La0.6Sr0.4Fe0.8Co0.2O3-δ as oxygen electrode.

High Temperature Steam Electrolysis, based on solid oxide electrolysis cells (SOEC) is a promising way to produce hydrogen with high efficiencies. The use of steam instead of liquid water requires less energy for the water molecule splitting, and the high temperature operation (between 700 and 900°C) allows the replacement of a part of the electrical energy by heat, which allows in theory a significant increase of the electrical efficiency compared to alkaline and PEM water electrolysis. Most of works in the field of SOEC around the world are carried out at the cell or stack level. Only few results at the system level, that is to say including the stack and all BoP (balance of plant) components, are reported in literature, although it is a key point because the heat management of the system has to be optimized to effectively reach the high electrical efficiency expected. For that purpose, the CEA-LITEN has designed and tested a packaged SOEC system demonstrator. It allows producing between 1 and 2.5 Nm3/h of H2 depending on the selected operating point, based on a single stack and the required auxiliaries, including a steam generator at 150°C and high temperature exchangers to preheat the inlet flows from heat recovered in the exhaust gases. A 25-cell-stack already validated in terms of performance [1] is the "heart" of the system. The stack as well as the other components of the system will be described in details, as well as the test results. The first test is presented in Figure 2. At 700°C, the system produces 1.2 Nm3/h of H2 with a total electrical consumption of 3.9 kWh/Nm3, achieving 92% of efficiency, this efficiency corresponding to the higher heating value (HHV) of the produced hydrogen vs the electrical consumption of the system. Indeed, Fig. 2 shows that during the first 3 hours of operation corresponding to the standby mode and endothermic operation, an external heating (through furnace resistances) is required. But after 3 hours, the operation mode switches from endothermic to slightly exothermic mode, leading to an increase of the hydrogen production up to the targeted flow rate of 1.2 Nm3/h after 5 hours, which is associated to a decrease of the furnace power and an increase of the efficiency. It can be seen that after 5 hours, the furnace power is decreased to zero, without any decrease of the stack temperature. It demonstrates that a 150°C heat source temperature is sufficient for the steam generation, and that a slightly exothermic operating mode of the stack is sufficient to preheat the inlet gas up to 700°C and compensate the heat losses of the system. [1] M. Reytier et al, 20th World Hydrogen Energy Conference, 15-20th June 2014, Gwangiu, Korea; submitted to International Journal of Hydrogen Energy. Figure 1