Effect of atmosphere change paths on the induced chemical expansion

International audienceThis study presents the relevant aspects of the approach developed at Institut PRISME to model strain in the mixed ionic and electronic conductors (MIEC) membrane for reforming of methane into synthesis gas (H2/CO). This macroscopic approach is based on the assumption of strain partition and on the choice of oxygen activity as a state variable. It leads to a thermo-chemo-mechanical model taking into account oxygen diffusion as well as elastic, thermal and chemical expansion phenomena. A chemical expansion model is proposed. The kinetics of a macroscopic bulk diffusion model has been fitted by simulation to chemical dilatometry tests. The transient and the steady-state stress distribution in a membrane reactor for partial oxidation of methane (POM) have been simulated in various conditions

Catalytic Membrane Reactor: Multilayer membranes elaboration

International audienceMethane conversion to syngas is very attractive for hydrogen or clean fuel production and provides an alternative to oil products. An efficient architecture for the membrane reactor is constituted of a porous support, a thin dense membrane and a catalyst layer. This work is focused on the elaboration process of such asymmetric membranes by co-sintering of at least the porous support and the dense membrane and specially the choice of well adapted materials. La0.8Sr0.2Fe0.7Ga0.3O3-δ perovskite material has been chosen as the dense membrane because it exhibits a good compromise between oxygen flux and stability. The choice of the material for the porous support is mainly oriented by the sintering behaviour of the membrane, the thermal expansion behaviour of both layers to avoid cracks formation under working conditions and the chemical inertness of both materials. Several formulations fulfilling these three requirements were synthesized by liquid phase reaction and tape-cast. A pore forming agent was added in the support tapecasting slurry in order to create a controlled porosity. Then, the porous support has been characterized in term of gas permeability and thermal expansion under working conditions. Keywords: Ceramic membrane, co-sintering, perovskite, syngas, mixed conducting materials

Oxygen permeation and dimensional stability under pO2 gradient of (La,Sr)(Fe, Ga)O3-delta perovskite membranes

International audienceNatural gas conversion into syngas, is very attractive for hydrogen or cleanfuel production and provides a new alternative to oil products ......

Chemical expansion of La0.8Sr0.2Fe0.7Ga0.3O3-δ

International audienceThis paper deals with the chemical expansion measurements and modelling of La0.8Sr0.2Fe0.7Ga0.3O3-δ. The expansion behavior has been evaluated using a dilatometer and X-ray diffraction over a wide range of temperatures (RT to 1373 K) and oxygen partial pressures (10−21 to 1 atm). The material stoichiometry evolution with temperature and oxygen partial pressure has been measured using thermogravimetry analysis at different oxygen partial pressure, from 10−21 to 0.5 atm and from RT to 1473 K. Considering a typical defect model for lanthanum ferrite oxides, chemical expansion depends linearly on the Fe4+ concentration rather than on the oxygen vacancy concentration. A model of chemical expansion as a function of pO2 and temperature is then proposed. It helps to understand and anticipate the chemical expansion behavior exhibited by this material when used as Ionic Transport Membrane (ITM)

Oxygen permeation, thermal and chemical expansion of (La, Sr)(Fe, Ga)O3−δ perovskite membranes

International audienceDense ceramic membranes made from mixed conductors are interesting because of their potential applications formethane conversion into syngas (H2 and CO mixture). Such membranes need to present a low differential dimensional variation between the opposite faces submitted to a large gradient of oxygen partial pressure, in order to minimize mechanical stresses generated through the membrane thickness. Besides, high oxygen permeability is required for high methane reforming rate. La(1−x)SrxFe(1−y)GayO3−δ materials fulfil these two main requirements and were retained as membranes in catalytic membrane reactors (CMR). The variations of expansion and oxygen permeation of La(1−x)SrxFe(1−y)GayO3−δ perovskite materials with the partial substitution of lanthanum and iron cations, temperature and oxygen partial pressure, were studied. For low temperatures (800 ◦C), TEC, then dimensional stability of the membrane, and oxygen permeation of La(1−x)SrxFe(1−y)GayO3−δ materials, are significantly affected by Sr content and oxygen partial pressure. Ga has a stabilisation effect on the TEC and has no influence on oxygen permeation flux. A good compromise between dimensional stability and oxygen permeation of materials was found to be La0.7Sr0.3Fe0.7Ga0.3O3−δ compositio

Structure-based optimization of potent, selective, and orally bioavailable CDK8 inhibitors discovered by high-throughput screening

The mediator complex-associated cyclin dependent kinase CDK8 regulates beta-catenin-dependent transcription following activation of WNT signaling. Multiple lines of evidence suggest CDK8 may act as an oncogene in the development of colorectal cancer. Here we describe the successful optimization of an imidazo-thiadiazole series of CDK8 inhibitors that was identified in a high-throughput screening campaign and further progressed by structure-based design. In several optimization cycles, we improved the microsomal stability, potency, and kinase selectivity. The initial imidazo-thiadiazole scaffold was replaced by a 3-methyl-1H-pyrazolo[3,4-b]-pyridine which resulted in compound 25 (MSC2530818) that displayed excellent kinase selectivity, biochemical and cellular potency, microsomal stability, and is orally bioavailable. Furthermore, we demonstrated modulation phospho-STAT1, a pharmacodynamic biomarker of CDK8 activity, and tumor growth inhibition in an APC mutant SW620 human colorectal carcinoma xenograft model after oral administration. Compound 25 demonstrated suitable potency and selectivity to progress into preclinical in vivo efficacy and safety studies

Prototype Biodiversity Digital Twin: Real-time bird monitoring with citizen-science data

Bird populations respond rapidly to environmental change making them excellent ecological indicators. Climate shifts advance migration, causing mismatches in breeding and resources. Understanding these changes is crucial to monitor the state of the environment. Citizen science offers vast potential to collect biodiversity data. We outline a project that combines citizen science with AI-based bird sound classification. The mobile app records bird vocalisations that are classified by AI and stored for re-analysis. Additionally, it shows a shared observation board that visualises collective classifications. By merging long-term monitoring and modern citizen science, this project harnesses the strength of both approaches for comprehensive bird population monitoring

2,8-Disubstituted-1,6-Naphthyridines and 4,6-Disubstituted-Isoquinolines with Potent, Selective Affinity for CDK8/19

We demonstrate a designed scaffold-hop approach to the discovery of 2,8-disubstituted-1,6-naphthyridine- and 4,6-disubstituted-isoquinoline-based dual CDK8/19 ligands. Optimized compounds in both series exhibited rapid aldehyde oxidase-mediated metabolism, which could be abrogated by introduction of an amino substituent at C5 of the 1,6-naphthyridine scaffold or at C1 of the isoquinoline scaffold. Compounds 51 and 59 were progressed to in vivo pharmacokinetic studies, and 51 also demonstrated sustained inhibition of STAT1SER727 phosphorylation, a biomarker of CDK8 inhibition, in an SW620 colorectal carcinoma human tumor xenograft model following oral dosing

Genome Sequence of the Saprophyte Leptospira biflexa Provides Insights into the Evolution of Leptospira and the Pathogenesis of Leptospirosis

Leptospira biflexa is a free-living saprophytic spirochete present in aquatic environments. We determined the genome sequence of L. biflexa, making it the first saprophytic Leptospira to be sequenced. The L. biflexa genome has 3,590 protein-coding genes distributed across three circular replicons: the major 3,604 chromosome, a smaller 278-kb replicon that also carries essential genes, and a third 74-kb replicon. Comparative sequence analysis provides evidence that L. biflexa is an excellent model for the study of Leptospira evolution; we conclude that 2052 genes (61%) represent a progenitor genome that existed before divergence of pathogenic and saprophytic Leptospira species. Comparisons of the L. biflexa genome with two pathogenic Leptospira species reveal several major findings. Nearly one-third of the L. biflexa genes are absent in pathogenic Leptospira. We suggest that once incorporated into the L. biflexa genome, laterally transferred DNA undergoes minimal rearrangement due to physical restrictions imposed by high gene density and limited presence of transposable elements. In contrast, the genomes of pathogenic Leptospira species undergo frequent rearrangements, often involving recombination between insertion sequences. Identification of genes common to the two pathogenic species, L. borgpetersenii and L. interrogans, but absent in L. biflexa, is consistent with a role for these genes in pathogenesis. Differences in environmental sensing capacities of L. biflexa, L. borgpetersenii, and L. interrogans suggest a model which postulates that loss of signal transduction functions in L. borgpetersenii has impaired its survival outside a mammalian host, whereas L. interrogans has retained environmental sensory functions that facilitate disease transmission through water

La station de <i>Bergusium</i> et le site des Buissières à Panossas (Isère) : de la toponymie à l’archéologie

International audienceThis article focuses on the Bergusium/Birgusia statio to the east of Vienne, traditionally considered to be the current town of Bourgoin-Jallieu (Isère). The scarcity and widespread dispersion of the remains discovered, as well as issues of toponymic derivation, suggest other localities, the foremost of which is Mount Briançon, several kilometres to the west. Its name is derived from the Celtic berg-/brig-, similar to the theonym Bergusia referred to in an Alesian inscription and related to a tutelary goddess of mining in these mountains. Reinforced by the pattern of names in Transalpine and Cisalpine Gaul, this hypothesis would fit well with Briançon, which represents the region’s main Oolitic iron ore deposit. Backed by its eastern foothills, the site of Buissières in Panossas suggests other archaeological arguments to that effect. Located in a valley overlooking the Velin Plain and Bourbre Valley, it is at the junction of two major roads connecting the settlements of Vienne and Lugdunum to Italy via the Alpine passes. Excavations conducted since 2012 have unearthed a vast monumental complex that included stables, blacksmiths’ workshops, storage areas, kitchens and accommodations. It comprised all the features of a high-capacity roadhouse that could correspond to the Bergusium referred to in the Itineraries or to one of its associated facilities.Cet article s’intéresse à la statio de Bergusium/Birgusia à l’est de Vienne, identifiée par la tradition à l’agglomération actuelle de Bourgoin-Jallieu (Isère). La rareté et la dispersion des vestiges découverts ainsi que des problèmes de filiation toponymique invitent à envisager d’autres localisations, au premier rang desquelles figure le mont Briançon, situé quelques kilomètres plus à l’ouest. Son nom dérivé du celtique berg-/brig- est rapproché du théonyme Bergusia mentionné par une inscription d’Alésia et identifié à une déesse tutélaire des monts miniers. Confortée par la répartition des toponymes en Gaule Transalpine et Cisalpine, cette hypothèse s’appliquerait bien au Briançon, qui constitue le principal gisement de fer oolithique à l’échelle régionale. Adossé à son piémont oriental, le site des « Buissières » à Panossas apporte d’autres arguments archéologiques en ce sens. Localisé dans un vallon surplombant la plaine du Velin et la vallée de la Bourbre, il s’inscrit au point de jonction de deux voies majeures reliant les colonies de Vienne et de Lugdunum à l’Italie via les cols alpins. Les fouilles conduites depuis 2012 y ont mis au jour un vaste complexe monumental qui associe stabulations, ateliers de forge, entrepôts, cuisines et locaux d’hébergement. Il réunit tous les critères d’une station routière de grande capacité, susceptible de correspondre à la Bergusium des Itinéraires ou à l’un de ses équipements annexes