The role of transcription factories-mediated interchromosomal contacts in the organization of nuclear architecture

Using numerical simulations, we investigate the underlying physical effects responsible for the overall organization of chromosomal territories in interphase nuclei. In particular, we address the following three questions: (i) why are chromosomal territories with relatively high transcriptional activity on average, closer to the centre of cell's nucleus than those with the lower activity? (ii) Why are actively transcribed genes usually located at the periphery of their chromosomal territories? (iii) Why are pair-wise contacts between active and inactive genes less frequent than those involving only active or only inactive genes? We show that transcription factories-mediated contacts between active genes belonging to different chromosomal territories are instrumental for all these features of nuclear organization to emerge spontaneously due to entropic effects arising when chromatin fibres are highly crowded

Analysis of solid-state battery interfaces for electric vehicle and renewable energy applications

Les interfaces sont la clef pour améliorer les performances et la durée de vie des batteries dîtes « tout-solide ». Jusqu'à présent leur études reste très difficiles car elles sont enterrées dans la batterie. L'objectif de ma thèse est de développer des méthodes analytiques pour caractériser les interfaces solide/solide et plus particulièrement surmonter les difficultés d'accès aux interfaces enfouies par la réalisation de coupe transverse. Résultats : une méthode de préparation par faisceau d'ion argon a été élaborée sur un système modèle et caractérisée par des méthodes spectroscopiques (XPS, AES, SAM) et spectrométriques (ToF-SIMS). Il en résulte que la méthode appliquée au système modèle n'inflige pas de dégâts à la nouvelle surface crée, ce qui valide cette approche pour l'analyse des interfaces solide/solide enfouies dans les batteries tout-solide. Valorisation : - Lopez, I.; Morey, J.; Madec, L.; Ledeuil, J.-B.; Martinez H.; A critical discussion on the analysis of buried interfaces in Li solid-state batteries, Manuscrit envoyé au Journal of Materials Chemistry A - Session poster au Journées de Spectroscopies d'Electrons 2021 (JSE 2021)Interfaces are critical element for all-solid-state batteries performance and lifetime but their study remains very challenging so far because they are buried in the entire battery stack. The objective is to develop analytical methods to characterise such solid/solid interfaces and particularly to overcome the challenge in accessing buried interfaces through cross-section preparation. Results : An argon ion beam preparation method was developed on a model system and characterized by spectroscopic (XPS, AES, SAM) and spectrometric (ToF-SIMS) methods. The application of this method on a model system does not inflict damage on the newly created surface which validate this approach for the analysis of buried solid/solid interfaces in all-soli-state batteries Valorization : - Lopez, I.; Morey, J.; Madec, L.; Ledeuil, J.-B.; Martinez H.; A critical discussion on the analysis of buried interfaces in Li solid-state batteries, Submitted Manuscript in Journal of Materials Chemistry A - Poster session in French Annual Workshop on Electron Spectroscopy 202

Analyse des interfaces de batteries tout solide pour des applications véhicules électriques et energies renouvelables

Interfaces are critical element for all-solid-state batteries performance and lifetime but their study remains very challenging so far because they are buried in the entire battery stack. The objective is to develop analytical methods to characterise such solid/solid interfaces and particularly to overcome the challenge in accessing buried interfaces through cross-section preparation. Results : An argon ion beam preparation method was developed on a model system and characterized by spectroscopic (XPS, AES, SAM) and spectrometric (ToF-SIMS) methods. The application of this method on a model system does not inflict damage on the newly created surface which validate this approach for the analysis of buried solid/solid interfaces in all-soli-state batteries Valorization : -Lopez, I.; Morey, J.; Madec, L.; Ledeuil, J.-B.; Martinez H.; A critical discussion on the analysis of buried interfaces in Li solid-state batteries, Submitted Manuscript in Journal of Materials Chemistry A -Poster session in French Annual Workshop on Electron Spectroscopy 2021Les interfaces sont la clef pour améliorer les performances et la durée de vie des batteries dîtes « tout-solide ». Jusqu'à présent leur études reste très difficiles car elles sont enterrées dans la batterie. L'objectif de ma thèse est de développer des méthodes analytiques pour caractériser les interfaces solide/solide et plus particulièrement surmonter les difficultés d'accès aux interfaces enfouies par la réalisation de coupe transverse. Résultats : une méthode de préparation par faisceau d'ion argon a été élaborée sur un système modèle et caractérisée par des méthodes spectroscopiques (XPS, AES, SAM) et spectrométriques (ToF-SIMS). Il en résulte que la méthode appliquée au système modèle n'inflige pas de dégâts à la nouvelle surface crée, ce qui valide cette approche pour l'analyse des interfaces solide/solide enfouies dans les batteries tout-solide. Valorisation : -Lopez, I.; Morey, J.; Madec, L.; Ledeuil, J.-B.; Martinez H.; A critical discussion on the analysis of buried interfaces in Li solid-state batteries, Manuscrit envoyé au Journal of Materials Chemistry A -Session poster au Journées de Spectroscopies d'Electrons 2021 (JSE 2021

Cross-section nano-Auger/SEM analysis to reveal bulk chemical/morphological properties of composites for energy storage

International audienceComposite materials for energy storage such as powders, electrodes or battery stack often require probing their bulk chemical/morphological properties, which remains challenging so far with conventional analytical methods. In this work, Ar + milling cross-section is proposed to reveal the intrinsically buried bulk information of three different composites without physical/chemical change. Then, nano-Auger/scanning electron microscopy (SEM) analysis is proposed to investigate their bulk properties at both micro-and nano-scales. For MnCo-based powders with micrometric particles, it allowed revealing the bulk porosity and the bulk nano-or micro-Mn/Co distribution. For micrometer thick TiSnSb-based electrodes, it allowed proving the conversion reaction over long term cycling (i.e. the participation of the electrochemically inactive Ti) while revealing the TiSnSb particles morphological evolution (shell to core spreading/pulverization into porous structure) and SEI formation inside the porous TiSnSb. For PEO-based solid battery stacks, the cross-section allowed revealing well-defined interfaces so that reliable interfaces analysis can thus be perform. Advantage/limitation of this cross-section nano-Auger/SEM approach are also discussed. Overall, this work opens the door for future development of Ar + milling cross-section and Auger analysis as powerful tools to reveal/study buried chemical/morphological properties at micro-and nano-scales even beyond the energy storage field

Operando Auger/XPS using an electron beam to reveal the dynamics/morphology of Li plating and interphase formation in solid-state batteries

International audienceInterfaces and their understanding/control are the key to pave the way for the development of solid-state batteries. This work focuses on the development of operando Auger cycling using an electron beam to investigate the Li/solid electrolyte (SE) interphases. To do so, the fully tunable electron gun of the Auger was applied on top of a model Li/Li6PS5Cl(Arg) stack, allowing charge build up at the Arg surface and Li+ migration from the lithium electrode followed by SE interphase formation and Li plating. Overall, it is found that (i) Li6PS5Cl is first reduced to Li2S, LiCl and Li3P while (ii) Li plating occurs almost concomitantly and (iii) proceeds until the end of the operando cycling. These results were then confirmed by operando XPS using an electron beam. Importantly, this study highlights that operando Auger is more powerful than operando XPS as it provides visual observation of the dynamics/morphology of both Li/solid electrolyte interphase formation and Li plating together with reliable chemical information. This study thus opens the door for future development of operando Auger cycling using an electron beam as a powerful approach to better understand the interfaces in solid-state batteries

Methodological developments to expose and analyse buried interfaces in lithium solid-state batteries using

Lithium solid-state batteries (SSBs) are a promising technology for electrochemical energy storage systems. So far, the performance of SSBs are mainly governed by the electro-chemo-mechanical properties of the diverse solid/solid interfaces and their evolution upon cycling. However, as these interfaces are buried in the battery stack, their comprehensive understanding remains a challenge. Here, we thus provide some advances in methodological developments for ex situ, in situ and operando cycling/analysis of these buried interfaces. It is showed that noble gaz ion milling at liquid nitrogen temperature is a suitable and reproducible method to prepare cross-section without any chemical/physical change even for polymer-based SSBs. In addition, innovative operando cycling using Auger analysis was proposed for the first time on a model Li/Li6PS5Cl stack. The interest of this approach is to be able to proceed without a dedicated electrochemical cell and to use the fully adjustable electron beam of the auger to create a surface potential difference followed by lithium migration then SEI (Solid Electrolyte Interface) formation and Li plating. Overall, this work should greatly benefits to all researchers working on buried interfaces study in lithium solid-state batteries

Mitochondrial Lon protease in human disease and aging: Including an etiologic classification of Lon-related diseases and disorders

The Mitochondrial Lon protease, also called LonP1 is a product of the nuclear gene LONP1. Lon is a major regulator of mitochondrial metabolism and response to free radical damage, as well as an essential factor for the maintenance and repair of mitochondrial DNA. Lon is an ATP-stimulated protease that cycles between being bound (at the inner surface of the inner mitochondrial membrane) to the mitochondrial genome, and being released into the mitochondrial matrix where it can degrade matrix proteins. At least three different roles or functions have been ascribed to Lon: 1) Proteolytic digestion of oxidized proteins and the turnover of specific essential mitochondrial enzymes such as aconitase, TFAM, and StAR; 2) Mitochondrial (mt)DNA-binding protein, involved in mtDNA replication and mitogenesis; and 3) Protein chaperone, interacting with the Hsp60–mtHsp70 complex. LONP1 orthologs have been studied in bacteria, yeast, flies, worms, and mammals, evincing the widespread importance of the gene, as well as its remarkable evolutionary conservation. In recent years, we have witnessed a significant increase in knowledge regarding Lon's involvement in physiological functions, as well as in an expanding array of human disorders, including cancer, neurodegeneration, heart disease, and stroke. In addition, Lon appears to have a significant role in the aging process. A number of mitochondrial diseases have now been identified whose mechanisms involve various degrees of Lon dysfunction. In this paper we review current knowledge of Lon's function, under normal conditions, and we propose a new classification of human diseases characterized by a either over-expression or decline or loss of function of Lon. Lon has also been implicated in human aging, and we review the data currently available as well as speculating about possible interactions of aging and disease. Finally, we also discuss Lon as potential therapeutic target in human disease