Université Paris-Saclay

About: Université Paris-Saclay is a education organization based out in Gif-sur-Yvette, France. It is known for research contribution in the topics: Population & Context (language use). The organization has 29307 authors who have published 43183 publications receiving 867404 citations.

A rhombohedral ferroelectric phase in epitaxially strained Hf0.5Zr0.5O2 thin films.

Abstract: Hafnia-based thin films are a favoured candidate for the integration of robust ferroelectricity at the nanoscale into next-generation memory and logic devices This is because their ferroelectric polarization becomes more robust as the size is reduced, exposing a type of ferroelectricity whose mechanism still remains to be understood Thin films with increased crystal quality are therefore needed We report the epitaxial growth of Hf05Zr05O2 thin films on (001)-oriented La07Sr03MnO3/SrTiO3 substrates The films, which are under epitaxial compressive strain and predominantly (111)-oriented, display large ferroelectric polarization values up to 34 μC cm−2 and do not need wake-up cycling Structural characterization reveals a rhombohedral phase, different from the commonly reported polar orthorhombic phase This finding, in conjunction with density functional theory calculations, allows us to propose a compelling model for the formation of the ferroelectric phase In addition, these results point towards thin films of simple oxides as a vastly unexplored class of nanoscale ferroelectrics Ferroelectric hafnia occurs only in a thin-film orthorhombic phase that needs wake-up cycling to induce ferroelectricity Here, by growing thin-film Hf05Zr05O2 under strain, a polar rhombohedral phase is achieved that does not require cycling

VirSorter2: a multi-classifier, expert-guided approach to detect diverse DNA and RNA viruses.

Abstract: Viruses are a significant player in many biosphere and human ecosystems, but most signals remain “hidden” in metagenomic/metatranscriptomic sequence datasets due to the lack of universal gene markers, database representatives, and insufficiently advanced identification tools. Here, we introduce VirSorter2, a DNA and RNA virus identification tool that leverages genome-informed database advances across a collection of customized automatic classifiers to improve the accuracy and range of virus sequence detection. When benchmarked against genomes from both isolated and uncultivated viruses, VirSorter2 uniquely performed consistently with high accuracy (F1-score > 0.8) across viral diversity, while all other tools under-detected viruses outside of the group most represented in reference databases (i.e., those in the order Caudovirales). Among the tools evaluated, VirSorter2 was also uniquely able to minimize errors associated with atypical cellular sequences including eukaryotic genomes and plasmids. Finally, as the virosphere exploration unravels novel viral sequences, VirSorter2’s modular design makes it inherently able to expand to new types of viruses via the design of new classifiers to maintain maximal sensitivity and specificity. With multi-classifier and modular design, VirSorter2 demonstrates higher overall accuracy across major viral groups and will advance our knowledge of virus evolution, diversity, and virus-microbe interaction in various ecosystems. Source code of VirSorter2 is freely available ( https://bitbucket.org/MAVERICLab/virsorter2 ), and VirSorter2 is also available both on bioconda and as an iVirus app on CyVerse ( https://de.cyverse.org/de ).

Heterogeneity of neuroblastoma cell identity defined by transcriptional circuitries

Abstract: Neuroblastoma is a tumor of the peripheral sympathetic nervous system(1), derived from multipotent neural crest cells (NCCs). To define core regulatory circuitries (CRCs) controlling the gene expression program of neuroblastoma, we established and analyzed the neuroblastoma super-enhancer landscape. We discovered three types of identity in neuroblastoma cell lines: a sympathetic noradrenergic identity, defined by a CRC module including the PHOX2B, HAND2 and GATA3 transcription factors (TFs); an NCC-like identity, driven by a CRC module containing AP-1 TFs; and a mixed type, further deconvoluted at the single-cell level. Treatment of the mixed type with chemotherapeutic agents resulted in enrichment of NCC-like cells. The noradrenergic module was validated by ChIP-seq. Functional studies demonstrated dependency of neuroblastoma with noradrenergic identity on PHOX2B, evocative of lineage addiction. Most neuroblastoma primary tumors express TFs from the noradrenergic and NCC-like modules. Our data demonstrate a previously unknown aspect of tumor heterogeneity relevant for neuroblastoma treatment strategies.

Increasing soil carbon storage: mechanisms, effects of agricultural practices and proxies. A review

Abstract: The international 4 per 1000 initiative aims at supporting states and non-governmental stakeholders in their efforts towards a better management of soil carbon (C) stocks. These stocks depend on soil C inputs and outputs. They are the result of fine spatial scale interconnected mechanisms, which stabilise/destabilise organic matter-borne C. Since 2016, the CarboSMS consortium federates French researchers working on these mechanisms and their effects on C stocks in a local and global change setting (land use, agricultural practices, climatic and soil conditions, etc.). This article is a synthesis of this consortium’s first seminar. In the first part, we present recent advances in the understanding of soil C stabilisation mechanisms comprising biotic and abiotic processes, which occur concomitantly and interact. Soil organic C stocks are altered by biotic activities of plants (the main source of C through litter and root systems), microorganisms (fungi and bacteria) and ‘ecosystem engineers’ (earthworms, termites, ants). In the meantime, abiotic processes related to the soil-physical structure, porosity and mineral fraction also modify these stocks. In the second part, we show how agricultural practices affect soil C stocks. By acting on both biotic and abiotic mechanisms, land use and management practices (choice of plant species and density, plant residue exports, amendments, fertilisation, tillage, etc.) drive soil spatiotemporal organic inputs and organic matter sensitivity to mineralisation. Interaction between the different mechanisms and their effects on C stocks are revealed by meta-analyses and long-term field studies. The third part addresses upscaling issues. This is a cause for major concern since soil organic C stabilisation mechanisms are most often studied at fine spatial scales (mm–μm) under controlled conditions, while agricultural practices are implemented at the plot scale. We discuss some proxies and models describing specific mechanisms and their action in different soil and climatic contexts and show how they should be taken into account in large scale models, to improve change predictions in soil C stocks. Finally, this literature review highlights some future research prospects geared towards preserving or even increasing C stocks, our focus being put on the mechanisms, the effects of agricultural practices on them and C stock prediction models.