Understanding the cation ordering transition in high-voltage spinel LiNi0.5Mn1.5O4 by doping Li instead of Ni

We determined how Li doping affects the Ni/Mn ordering in high-voltage spinel LiNi0.5Mn1.5O4(LNMO) by using neutron diffraction, TEM image, electrochemical measurements, and NMR data. The doped Li occupies empty octahedral interstitials (16c site) before the ordering transition, and can move to normal octahedral sites (16d (4b) site) after the transition. This movement strongly affects the Ni/Mn ordering transition because Li at 16c sites blocks the ordering transition pathway and Li at 16d (4b) sites affects electrostatic interactions with transition metals. As a result, Li doping increases in the Ni/Mn disordering without the effect of Mn3+ ions even though the Li-doped LNMO undergoes order-disorder transition at 700 degrees C. Li doping can control the amount of Ni/Mn disordering in the spinel without the negative effect of Mn3+ ions on the electrochemical property.111Ysciescopu

Medical and Paramedical Care of Patients With Cerebellar Ataxia During the COVID-19 Outbreak: Seven Practical Recommendations of the COVID 19 Cerebellum Task Force

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV2), the cause of the current pandemic coronavirus disease 2019 (COVID-19), primarily targets the respiratory system. Some patients also experience neurological signs and symptoms ranging from anosmia, ageusia, headache, nausea, and vomiting to confusion, encephalitis, and stroke. Approximately 36% of those with severe COVID-19 experience neurological complications. The virus may enter the central nervous system through the olfactory nerve in the nasal cavity and damage neurons in the brainstem nuclei involved in the regulation of respiration. Patients with cerebellar ataxia (CA) are particularly vulnerable to severe outcome if they contract COVID-19 because of the complexity of their disease, the presence of comorbidities, and their use of immunosuppressive therapies. Most CA patients burdened by progressive neurologic deficits have substantially impaired mobility and other essential functions, for which they rely heavily on ambulatory services, including rehabilitation and psychosocial care. Cessation of these interventions because of isolation restrictions places the CA patient population at risk of further deterioration. This international panel of ataxia experts provides recommendations for neurologists caring for patients with CA, emphasizing a pro-active approach designed to maintain their autonomy and well-being: continue long-term medications, promote rehabilitation efforts, utilize the technology of virtual visits for regular contact with healthcare providers, and pay attention to emotional and psychosocial health. Neurologists should play an active role in decision-making in those CA cases requiring escalation to intensive care and resuscitation. Multi-disciplinary collaboration between care teams is always important, and never more so than in the context of the current pandemic

The Classification of Autosomal Recessive Cerebellar Ataxias : a Consensus Statement from the Society for Research on the Cerebellum and Ataxias Task Force

There is currently no accepted classification of autosomal recessive cerebellar ataxias, a group of disorders characterized by important genetic heterogeneity and complex phenotypes. The objective of this task force was to build a consensus on the classification of autosomal recessive ataxias in order to develop a general approach to a patient presenting with ataxia, organize disorders according to clinical presentation, and define this field of research by identifying common pathogenic molecular mechanisms in these disorders. The work of this task force was based on a previously published systematic scoping review of the literature that identified autosomal recessive disorders characterized primarily by cerebellar motor dysfunction and cerebellar degeneration. The task force regrouped 12 international ataxia experts who decided on general orientation and specific issues. We identified 59 disorders that are classified as primary autosomal recessive cerebellar ataxias. For each of these disorders, we present geographical and ethnical specificities along with distinctive clinical and imagery features. These primary recessive ataxias were organized in a clinical and a pathophysiological classification, and we present a general clinical approach to the patient presenting with ataxia. We also identified a list of 48 complex multisystem disorders that are associated with ataxia and should be included in the differential diagnosis of autosomal recessive ataxias. This classification is the result of a consensus among a panel of international experts, and it promotes a unified understanding of autosomal recessive cerebellar disorders for clinicians and researchers

Nilearn for new use cases: Scaling up computational and community efforts

Introduction Nilearn (https://nilearn.github.io) is a well-established Python package that provides statistical and machine learning tools for fast and easy analysis of brain images with instructive documentation and a friendly community. This focus has led to its current position as a crucial part of the neuroimaging community’s open-source software ecosystem, supporting efficient and reproducible science [1]. It has been continuously developed over the past 10 years, currently with 900 stars, 500 forks, and 176 contributors on GitHub. Nilearn leverages and builds upon other central Python machine learning packages, such as Scikit-Learn [2], that are extensively used, tested, and optimized by a large scientific and industrial community. In recent years, efforts in Nilearn have been focused on meeting evolving community needs by increasing General Linear Model (GLM) support, interfacing with initiatives like fMRIPrep and BIDS, and improving the user documentation. Here we report on progress regarding our current priorities. Methods Nilearn is developed to be accessible and easy-to-use for researchers and the open-source community. It features user-focused documentation that includes a user guide and an example gallery as well as comprehensive contribution guidelines. Nilearn is also presented in tutorials and workshops throughout the year including the Montreal Artificial Intelligence and Neuroscience (MAIN) Educational Workshop, the OHBM Brainhack event, and for the Chinese Open Science Network. The community is encouraged to ask questions, report bugs, make suggestions for improvements or new features, and make direct contributions to the source code. We use the platforms Neurostars, GitHub, and Discord to interact with contributors and users on a daily basis. Nilearn adheres to best practices in software development including using version control, unit testing, and requiring multiple reviews of contributions. We also have a continuous integration infrastructure set up to automate many aspects of our development process and make sure our code is continuously tested and up-to-date. Results Nilearn supports methods such as image manipulation and processing, decoding, functional connectivity analysis, GLM, multivariate pattern analysis, along with plotting volumetric and surface data. In the latest release, cluster-level and TFCE-based family-wise error rate (FWER) control have been added to support the mass univariate and GLM analysis modules, expanding from the already implemented voxel-level correction method (see Fig1). Optimizing Nilearn’s maskers is also underway such as the recently added classes for handling multi-subject 4D image data. These also provide the option to use parallelization to speed up computation. In addition, Nilearn has introduced a new theme to update the documentation making the website more readable and accessible (https://nilearn.github.io/). This change also sets the stage for further improvement and modernisation of several aspects of the documentation, like the user guide. Development on Nilearn’s interfaces module added a new function to write BIDS-compatible model results to disk. This and further development of the BIDS interface will facilitate interaction with other relevant community tools such as FitLins [3]. Finally, several surface plotting enhancements are in progress including improving the API for background maps (see Fig2). Conclusion Nilearn is extensively used by researchers of the neuroimaging community due to its implementations of well-founded methods and visualization tools which are often essential in brain imaging research for quality control and communicating results. Recent work has highlighted areas where more active work is needed to scale the project both technically and socially, including: working with large datasets, better supporting analyses on the cortical surface, and advancing standard practice in neuroimaging statistics through active community outreach. References [1] Poldrack, R., Gorgolewski, K., Varoquaux, G. (2019). Computational and Informatic Advances for Reproducible Data Analysis in Neuroimaging Annual Review of Biomedical Data Science 2(1), 119-138. https://dx.doi.org/10.1146/annurev-biodatasci-072018-021237 [2] Pedregosa, F., Varoquaux, G., Gramfort, A., Michel, V., Thirion, B., Grisel, O., Blondel, M., Prettenhofer, P., Weiss, R., Dubourg, V., Vanderplas, J., Passos, A., Cournapeau, D., Brucher, M., Perrot, M., Duchesnay, E. (2011). Scikit-learn: Machine Learning in Python, Journal of Machine Learning Research, 12, 2825-2830. [3] Markiewicz, C. J., De La Vega, A., Wagner, A., Halchenko, Y. O., Finc, K., Ciric, R., Goncalves, M., Nielson, D. M., Kent, J. D., Lee, J. A., Bansal, S., Poldrack, R. A., Gorgolewski, K. J. (2022). poldracklab/fitlins: 0.11.0 (0.11.0). Zenodo. https://doi.org/10.5281/zenodo.7217447This poster was presented at OHBM 2023

Etude du phosphate de vanadyle comme matériau d'électrode de batteries Li-ion

PARIS-BIUSJ-Thèses (751052125) / SudocCentre Technique Livre Ens. Sup. (774682301) / SudocPARIS-BIUSJ-Physique recherche (751052113) / SudocSudocFranceF

Caractérisation et contrôle de l interface électrode / électrolyte d électrodes positives pour accumulateurs Li-ion

Les accumulateurs au lithium, largement développés pour l électronique portable, sont aujourd hui envisagés pour des applications en véhicules hybrides et électriques. Les limitations actuelles sont leur faible capacité et leur durée de vie limitée provenant entre autres de la nonmaitrise de l interface électrode positive / électrolyte. La présente étude porte sur la caractérisation et le contrôle des processus interfaciaux relatifs aux matériaux LiNi0.5Mn0.5O2, Li1.2Ni0.4Mn0.4O2 et LiFePO4 d électrode positive lors du stockage et du cyclage électrochimique. La thèse s'est concentrée sur la formation et l évolution de l'interphase formée par décomposition de l électrolyte, en fonction de l état de surface du matériau actif. Différents types de modifications ont été envisagés, tels qu une modification intrinsèque par vieillissement à l air ou par favorisation d une orientation cristalline particulière dans le cas de l olivine LiFePO4, ou encore par la surlithiation de l oxyde lamellaire LiNi0.5Mn0.5O2, sous la forme Li[Li0.2Ni0.4Mn0.4]O2. D autres types de modifications, considérées comme artificielles ou externes, reposent sur l usage d additifs dans l électrolyte ou d un dépôt hétérochimique en surface de Li1.2Ni0.4Mn0.4O2. Dans chaque cas, les espèces visibles à la surface des matériaux au cours du stockage et du cyclage sont corrélées aux performances électrochimiques des électrodes positives. L originalité du travail repose sur le développement d outils spectroscopiques tels que la RMN MAS (7Li, 19F et 31P) et l'EELS, parallèlement à l XPS, pour quantifier les interphases de manière absolue et en décrire l architecture.Lithium batteries, widely developed for portable electronics, are now being considered for applications in hybrid and electric vehicles. Their current limitations are the low capacity and limited cycle life caused notably by the uncontrolled positive electrode / electrolyte interface. The present study reports the characterization and attempts of control of interfacial processes occurring on LiNi0.5Mn0.5O2, Li1.2Ni0.4Mn0.4O2 and LiFePO4 positive electrode materials during their storage and electrochemical cycling. The thesis focuses on the formation and evolution of the interphase formed by decomposition of the electrolyte, depending on the surface chemistry of the active material. Different types of surface modifications have been proposed, such as intrinsic modifications upon aging in air or the promotion of a particular crystalline orientation in the case of olivine LiFePO4, or by overlithiation of the LiNi0. 5Mn0.5O2 oxide lamellar, under the form of Li [Li0.2Ni0.4Mn0.4]O2. Other types of modifications, considered as artificial or external, are based on the use of additives in the electrolyte or of a heterochemical coating on the surface of Li1.2Ni0.4Mn0.4O2. In each case, species detected on the surface of materials during storage and cycling are correlated with the electrochemical performance of the positive electrodes. The originality of the work is based primarily on the development of spectroscopic tools such as MAS NMR (7Li, 19F and 31P) and EELS, in parallel to XPS, to quantitatively describe the interphase and unravel its architecture.NANTES-BU Sciences (441092104) / SudocSudocFranceF

Communication engageante appliquée au tri sélectif : comparaison entre les techniques du pied-dans-la-porte et du double-pied-dans-la-porte.

International audienceDer Erfolg der Politik der Wiederverwertung von Abfall beruht auf der Akzeptanz jedes Einzelnen der für den häuslichen Alltag übernommenen Praktiken. Die gestellte Herausforderung für die Unternehmen besteht darin, dafür zu sorgen, dass die Mehrheit beim Sortieren von Müll vor Ort mitmacht. Das Zusammenbringen von Überzeugung und Verpflichtung in einem zum Mitmachen förderndem Gespräch ist eine Kommunikationsform, die kaum im Hinblick auf ein Verändern der Praktiken des Sortierverhaltens untersucht wurde. Die wenigen durchgeführten Studien sprechen sich dennoch nicht zu ihren Gunsten aus. Unsere Studie vergleicht drei verschiedene Formen des Überzeugungsgespräches : Wir verwendeten die Technik „Fuß-in-der-Tür“, eine abgeschwächte Form der Technik „Zwei-Füße-in-der-Tür“und eine stärker ausgeprägt verpflichtende Form der Technik „Zwei-Füße-in-der-Tür“. Messungen sechs Wochen nach dem Experiment lassen den Schluss zu, dass jede der eingesetzten Techniken des Überzeugungsgespräches bewirkt hat, die Sortier-Praktiken bei den Teilnehmern zu verändern. Die Auswirkungen des Überzeugungsgespräches variieren aber ferner auch in Abhängigkeit von der verwendeten Vorgehensweise im Experiment. Im einzeln wird deutlich, dass diese zunehmen im Zusammenhang mit Wiederholung und Wichtigkeit des Committment.The success of the policy of recycling of waste is based on the adoption by most people adapted domestic practices. The challenge for institutions is that many involved in the sorting device in place. By combining persuasion and commitment, binding communication is a form of communication unexplored in order to change the sorting practices. This study compares three different binding communication with variation of the free behavior : we experienced a foot-in-the-door, a weakly committing two-feet-in-the-door and a more committing two-feet-in-the-door. A measurement six weeks after the experiment conclude that each of the forms of binding communication permit to change sorting practices. Moreover, the committing behaviors modify effects of binding communication. More specifically, the behavioral change increase with repetition and importance of committing act.La réussite de la politique de revalorisation des déchets ménagers repose sur l’adoption par chacun de pratiques domestiques adaptées. L’enjeu pour les institutions concernées est que le plus grand nombre participe au dispositif de tri mis en place. En combinant persuasion et engagement, la communication engageante offre une forme de communication encore peu explorée dans le but de modifier les pratiques de tri. Les rares études réalisées plaident néanmoins en sa faveur. Notre étude compare trois formes de communication engageante différentes en faisant varier le soubassement comportemental : nous avons expérimenté un pied-dans-la-porte, un double-pied-dans-la-porte faiblement engageant et un double-pied-dans-la-porte fortement engageant. Une mesure réalisée six semaines après l’expérience permet de conclure que chacune des formes de communication engageante a permis de modifier les pratiques de tri auto-déclarées des participants. Les effets de la communication engageante varient également en fonction du soubassement comportemental. Plus précisément, ils augmentent avec la répétition et l’importance de l’acte engageant.El éxito de la política de revalorización de las basuras domésticas descansa en la adopción de cada una de las practicas domesticas adaptadas. La apuesta de parte de las instituciones concernidas es que la mayoría de personas participen al dispositivo de selección existente. Combinando persuasión y compromiso, la comunicación participativa ofrece una forma de comunicación aun poco explorada con el objetivo de modificar prácticas de reciclaje. Los raros estudios realizados, reclaman este tipo de técnicas. Nuestro estudio compara tres formas diferentes de comunicación participativa, variando la base comportamental : experimentamos un pie-en-la-puerta, un doble-pie-en-la-puerta débilmente participativo y un doble-pie-en-la-puerta fuertemente participativo. Una medida realizada seis semanas después de la experiencia permite concluir que cada una de las formas de comunicación participativa permitió modificar las prácticas de reciclaje auto-declaradas de los participantes. Los efectos de la comunicación participativa varían igualmente en función de la base comportamental. Más precisamente ellos aumentan con la repetición y la importancia del acto comprometido

Évolution de la surface de matériaux d'électrode positive pour accumulateurs au lithium au cours du vieillisement et du cyclage électrochimique

Les accumulateurs au lithium, largement développés pour l électronique portable, sont pressentis pour les véhicules hybrides et électriques. Les limitations actuelles sont leur faible capacité et leur durée de vie limitée provenant entre autres de la non-maîtrise de l interface électrode positive / électrolyte. L étude de l évolution de cette interface dans différentes conditions fait l objet de cette thèse. La présente étude concerne deux matériaux d électrode positive parmi les plus efficaces: LiFePO4 et LiNi0.5Mn0.5O2. Il apparaît d abord que les deux matériaux sont sensibles à l exposition à l atmosphère ambiante, mais qu ils réagissent différemment avec une oxydation-amorphisation pour l olivine et la formation de Li2CO3 pour l oxyde. Ces réactions amènent des changements de comportement lors du cyclage électrochimique. Dans un second temps, le contact avec un électrolyte liquide est considéré au repos puis en cyclage électrochimique. Les espèces visibles à la surface des électrodes positives sont des produits de décomposition de l électrolyte. Cette étude montre, en outre, la forte influence du potentiel sur les quantités d espèces lithiées présentes sur le matériau actif. L étude de films minces épitaxiés de LiNi0.5Mn0.5O2 est également abordée. Les conclusions de ce travail amènent une meilleure compréhension des interphases entre électrode positive et électrolyte conduisant à de nouvelles voies d optimisation des matériaux. Parallèlement à l XPS, la RMN MAS du 7Li a été utilisée pour révéler, au delà de la quantification, l intimité entre les couches de surface et le matériau actifLithium batteries, largely developed for portable devices, are expected for the hybrid and electric vehicles. Nevertheless, their restrictions include low capacity and lifetime which are partially caused by an uncontrolled interface between positive electrode and electrolyte. The study of the evolution of this interface under different conditions is the subject of this thesis. Our study concerns two intercalation materials for positive electrodes among the most efficient: LiFePO4 and LiNi0.5Mn0.5O2. Firstly, it appears that the two materials are sensitive to ambient atmosphere exposure but that they exhibit different reactivities. The olivine undergoes an oxidation-amorphization reaction while the oxide forms lithium carbonates. These interphases lead to behavior changes during the electrochemical cycling. The second part of this work focuses on the contact with the liquid electrolyte during soaking and during electrochemical cycling. The chemical species found on the positive electrodes are degradation products of the electrolyte. It demonstrates the strong influence of the potential on the quantities of lithiated species found on the surface of the active material. The study of LiNi0.5Mn0.5O2 epitaxial thin films has also been considered. The conclusions of this work bring a better understanding of the interphases between positive electrode and electrolyte and open new ways to the materials optimization.In parallel to XPS, 7Li MAS NMR has been used to reveal, additionally to the quantification, the intimacy between surface layers and active materialNANTES-BU Sciences (441092104) / SudocSudocFranceF

Understanding the cation ordering transition in high-voltage spinel LiNi0.5Mn1.5O4 by doping Li instead of Ni

International audienc

NMR monitoring of electrode/electrolyte interphase in the case of air-exposed and carbon coated LiFePO4

International audienceDegradation of the electrochemical performance of LiFePO4 upon air exposure, assigned to a corrosion-type aging mechanism, implies the incorporation of hydroxyl groups and the formation of an amorphous tavorite-like phase at the surface. Using a carbon coating provides an efficient protection from this detrimental process but also modifies the surface in contact with the electrolyte. The formation and evolution of electrode/electrolyte interphases forming on both air-aged and carbon coated LiFePO4 are discussed based on combined quantitative 7Li, 19F MAS NMR, EIS and EELS measurements. Concerning the air-aged LiFePO4, the electrode/electrolyte interactions are dominated by the dissolution of the active material and an exacerbated reaction of incorporated hydroxyl groups with the electrolyte salt, resulting in a LiF rich interphase. This dissolution of the outer part of active material particles is accompanied by the departure of the previously formed interphase and a new interphase is then formed on a newly exposed surface. The resistive LiF rich interphase passivates the active material particles during cycling, forming a resistive film, hindering both Li ion transfer and material corrosion. Cellulose acetate based carbon coating prevents air-aging but yields to an accumulation of organic lithiated species, allowing Li transfer and maintaining good electrochemical performance