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Science China Mathematics 2024年

作者： Carlos Simpson CNRS Laboratoire JA Dieudonne Parc Valrose Université C?te d'Azur

We show that relative character varieties having a fixed dimension d > 0, for irreducible orthogonal or symplectic local systems of rank r on P1-{0, 1, ∞}, are isomorphic via Katz's middle convolution to ones with a ...

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Molecular dynamics simulations of initial Pd and PdO nanocluster growth in a magnetron gas aggregation source

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Frontiers of Chemical Science and Engineering 2019年第2期13卷 324-329页

作者： Pascal Brault William Chamorro-Coral Sotheara Chuon Amael Caillard Jean-Marc Bauchire Stevè Baranton Christophe Coutanceau Erik Neyts GREMI UMR 7344 CNRS Universite d'Orleans45067 Orleans Cedex 2France IC2MP UMR 7285 CNRS Universite de Poitiers86073 Poitiers Cedex 9France department of Chemistry University of Antwerp2610 AntwerpBelgium

Molecular dynamics simulations are carried out for describing growth of Pd and PdO nanoclusters using the ReaxFF force field. The resulting nanocluster structures are successfully compared to those of nanoclusters experimentally grown in a gas aggregation source. The PdO structure is quasi-crystalline as revealed by high resolution transmission microscope analysis for experimental PdO nanoclusters. The role of the nanocluster temperature in the molecular dynamics simulated growth is highlighted.

关键词： molecular dynamics cluster growth plasma sputtering nanocatalyst

Single-emitter super-resolved imaging of radiative decay rate enhancement in dielectric gap nanoantennas

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Light(Science & Applications) 2024年第1期13卷 47-54页

作者： R.Margoth Córdova-Castro Bart van Dam Alberto lauri Stefan A.Maier Riccardo Sapienza Yannick de Wilde Ignacio Izeddin Valentina Krachmalnicoff Institut langevin ESPCI ParisPSL UniversityCNRSParisFrance The Blackett laboratory Department of PhysicsImperial College LondonLondonUK School of Physics and Astronomy Monash UniversityClaytonVictoriaAustralia Chair in Hybrid Nanosystems Ludwig-Maximilians Universität MünchenMuenchenGermany department of Physics University of OttawaOttawaONCanada

High refractive index dielectric nanoantennas strongly modify the decay rate via the Purcell effect through the design of radiative *** to their dielectric nature,the field is mainly confined inside the nanostructure and in the gap,which is hard to probe with scanning probe *** we use single-molecule fluorescence lifetime imaging microscopy(smFLIM)to map the decay rate enhancement in dielectric GaP nanoantenna dimers with a median localization precision of 14 *** measure,in the gap of the nanoantenna,decay rates that are almost 30 times larger than on a glass *** comparing experimental results with numerical simulations we show that this large enhancement is essentially radiative,contrary to the case of plasmonic nanoantennas,and therefore has great potential for applications such as quantum optics and biosensing.

关键词： dielectric decay radiative

Combining infrared and mode synthesizing atomic force microscopy： Application to the study of lipid vesicles inside Streptomyces bacteria

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Nano Research 2016年第6期9卷 1674-1681页

作者： Pauline Vitry Rolando Rebois Eric Bourillot Ariane deniset-Besseau Marie-Joelle Virolle~ Eric Lesniewska Alexandre Dazzi ICB UMR CNRS 6303 University ofBourgogne Franche Comte 21078 Dijon France LCP UMR CNRS 8000 University Paris-Sud 91405 Orsay France 12BC UMR CNRS 9198 University Paris-Sud 91190 Gif-Sur-Yvette France

We propose a new analytical approach combining vibrational spectroscopy and acoustic tomography for the detection and characterization of vesicles inside Streptomyces bacteria. Using atomic force microscopy and infrared spectroscopy （AFM-IR）, we detect the presence of triglyceride vesicles. Their sizes in depth are measured with high accuracy using mode synthesizing atomic force microscopy （MS-AFM）. We conducted a comparative study of AFM-IR and MS-AFM, and highlighted the advantages of the coupling of these techniques in having a full characterization （chemical, topographical, and volumetric） of a biological sample. With these complementary techniques, a complete access to the vesicle size distribution has been achieved with an accuracy of less than 50 nm. A 3D reconstruction of bacteria showing the in-depth distribution of vesicles is given to underline the great potential of the acoustic method.

关键词： nanoscale suDsurtace imaging atomic force microscop~ acoustic microscopy infrared microscopy biology

Histone Acetyltransferase AtGCN5/HAG1 Is a Versatile Regulator of developmental and Inducible Gene Expression in Arabidopsis

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Molecular Plant 2010年第4期3卷 670-677页

作者： Caroline Servet Natalia Conde e Silva Dao-Xiu Zhou Institut de Biologie des Plantes Universite Paris-sud 11 91405 Orsay France

Histone acetylation/deacetylation is a dynamic process and plays an important role in gene regulation. Histone acetylation homeostasis is regulated by antagonist actions of histone acetyltransferases （HAT） and deacetylases （HDAC）. Plant genome encodes multiple HATs and HDACs. The Arabidopsis HAT gene AtGCNS/HAGlplays an essential role in many plant development processes, such as meristem function, cell differentiation, leaf and floral organogenesis, and responses to environmental conditions such as light and cold, indicating an important role of this HAT in the regulation of both long-term developmental switches and short-term inducible gene expression. AtGCN5 targets to a large number of promoters and is required for acetylation of several histone H3 lysine residues. Recruitment of AtGCN5 to target promoters is likely to be mediated by direct or indirect interaction with DNA-binding transcription factors and/or by interaction with acetylated histone lysine residues on the targets. Interplay between AtGCN5 and other HATand HDAC is demonstrated to control specific regulatory pathways. Analysis of the role of AtGCN5 in light-inducible gene expression suggests a function of AtGCN5 in preparing chromatin commitment for priming inducible gene activation in plants.

关键词： Light regulation chromatin structure and remodeling gene regulation leaf/vegetative development meristem development.

larval interference competition between the native Neotropical mosquito Limatus durhamii and the invasive Aedes aegypti improves the fitness of both species

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Insect Science 2018年第6期25卷 1102-1107页

作者： Stanislas Talaga Alain dejean Clémence Mouza Yves Dumont Céline Leroy lnsUtut Pasteur de la Guyane Unitéd'Entomologie MédicaleCayenne cedexFrance CNRS UMR EcoFoGAgroParisTechCiradINRAUniversitédes AntillesUniversitéde GuyaneKourouFrance CNRS INPTUPSEcolabUniversitéde ToulouseToulouseFrance AMAP CIRADCNRSINRAIRDUniversit6MontpellierMontpellierFrance

Interspecific competition with native species during biological invasions can sometimes limit alien *** aimed to determine the potential ecological effects of Limatus durhamii Theobald 1901,a native Neotropical mosquito (Diptera:Culicidae) species,on the invasive species Aedes (Stegomyia)aegypti (Linnaeus 1762)that breeds in the same artificial water *** time and adult dry mass were measured in 3 rearing conditions:control (a single larva),intraspecific competition (2 conspecific larvae),and interspecific competition (2 heterospecific larvae).Food was provided ad libitum to eliminate exploitative *** ***,development time was not affected by interspecific interference competition (nonsignificant differences with the control)and the adult dry mass was significantly higher,meaning that individual fitness likely ***,because previous studies showed longer development time and lighter adults during competition with other invasive mosquitoes,it is likely that *** can express a different phenotype depending on the competing *** similar pattern found for *** females and the nonsignificant difference with the control for males explain in part why this species can compete with ***.

关键词： Aedes aegypti increased fitness interference competition Limatus durhamii phenotypic plasticity resistance to invasion

The Polycomb Complex PRC1:Composition and Function in Plants

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Journal of Genetics and Genomics 2013年第5期40卷 231-238页

作者： Anne Molitor Wen-Hui Shen Institut de Biologie Moléculaire des Plantes du CNRS Université de Strasbourg12 rue du Général Zimmer67084 StrasbourgFrance Institut J.-P.Bourgin UMR1318 INRA-AgroParisTechINRAroute de Saint Cyr78026 VersaillesFrance

Polycomb group（PcG） proteins are crucial epigenetic regulators conferring transcriptional memory to cell *** assemble into multi-protein complexes,e.g.,Polycomb Repressive Complex 1 and 2（PRC1,PRC2）,which are thought to act in a sequential manner to stably maintain gene ***2 induces histone H3 lysine 27（H3K27） trimethylation（H3K27me3）,which is subsequently read by PRCl that further catalyzes H2A monoubiquitination（H2Aub1）,creating a transcriptional silent chromatin ***2 components are conserved in plants and have been extensively characterized in *** contrast,PRCl composition and function are more diverged between animals and *** more recently,PRC1 existence in plants has been *** we review the aspects of plant specific and conserved PRC1 and highlight critical roles of PRC1 components in seed embryonic trait determinacy,shoot stem cell fate determinacy,and flower development in Arabidopsis.

关键词： Epigenetics Chromatin Histone modifications Polycomb PRC1 Arabidopsis development

MUF Resins Improved by Citric Acid as Adhesives for Wood Veneer Panels

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Journal of Renewable Materials 2023年第2期11卷 539-553页

作者： Claudio del Menezzi Antonio Pizzi Siham Amirou Xuedong Xi department of Forestry Engineering Faculty of TechnologyUniversity of BrasiliaBrasíliaBrazil LERMAB University of LorraineNancyFrance SeniorPost-Doctoral Internship LERMAB-ENSTIBUniversity of LorraineEpinalFrance Yunnan Key laboratory of Wood Adhesives and Glue Products College of Material Science and EngineeringSouthwest Forestry UniversityKunmingChina International Joint Research Center for Biomass Materials Southwest Forestry UniversityKunmingChina

This article presents the first applied results of using citric acid in combinations with a melamine-urea-formal-dehyde(MUF)resin for bonding wood *** chemical reactions involved are shown based on a MALDI ToF analysis of the reaction of the MUF resin with citric *** preliminary results of the physical and mechanical properties of the LVL prepared are also *** from Populus sp were used to manufacture 5-layer laminated veneer lumber(LVL)of small *** combinations of the amount of citric acid,MUF spread rate and pressing parameters were *** bonded with 20%of citric acid+100 g/m^(2)of MUF,hot-pressed using a 3-step process with maximum 1.5 MPa of pressure yielded the board with better dimensional stability and mechanical *** could be concluded that citric acid in combination with MUF can be used for bonding wood veneer and the research should be continued to study further the parameters involved and to enhance the results.

关键词： LVL wood adhesives citric acid MUF resins MALDI ToF mechanical performance

Abscisic Acid Signal off the STARTing Block

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Molecular Plant 2011年第4期4卷 562-580页

作者： Archana Joshi-Saha Christiane Valon Jeffrey Leung Institut des Sciences du Vegetal Centre National de la Recherche Scientifique UPR2355 1 Avenue de la Terrasse Bat. 23 91198 Gif-sur-Yvette France

The year 2009 marked a real turnaround in our understanding of the mode of abscisic acid （ABA） action. Nearly 25 years had elapsed since the first biochemical detection of ABA-binding proteins in the plasmalemma of Vicia guard cells was reported. This recent--and laudable--achievement is owed largely to the discovery of the soluble ABA receptors whose major interacting proteins happen to be some of the most well-established components of earliest steps in ABA signaling. These soluble receptors, with the double name of PYRABACTIN RESISTANCE （PYR） or REGUlaTORY COMPONENT OF ABA RECEPTOR （RCAR）, are a family of Arabidopsis proteins of about 150-200 amino acids that share a conserved START domain. The ABA signal transduction circuitry under non-stress conditions is muted by the clade A protein phosphatases 2C （PP2C）（notably HAB1, ABI1, and ABI2）. During the initial steps of ABA signaling, the binding of the hormone to the receptor induces a conformational change in the latter that allows it to sequester the PP2Cs. This excludes them from the negative regulation of the downstream ABA-activated kinases （OST1/SnRK2.6/SRK2E, SnRK2.2, and SnRK2.3）, thus unleashing the pathway by freeing them to phosphorylate downstream targets that now include several b-ZIP transcription factors, ion channels （SlaC1, KAT1）, and a NADPH oxidase （AtrbohF）. The discovery of this family of soluble receptors and the rich insight already gained from structural studies of their complexes with different isoforms of ABA, PP2C, and the synthetic agonist pyrabactin lay the foundation towards rational design of chemical switches that can bolster drought hardiness in plants.

关键词： Abiotic/environmental stress hormone biology signal transduction.

Chromatin Remodeling in Stem Cell Maintenance in Arabidopsis thaliana

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Molecular Plant 2009年第4期2卷 600-609页

作者： Wen-Hui Shen Lin Xu Institut de Biologie Moleculaire des Plantes (IBMP) du CNRS Universite de Strasbourg (UdS) 12 rue du General Zimmer 67084 Strasbourg Cedex France Present address: National Key laboratory of Plant Molecular Genetics Shanghai Institute of Plant Physiology and Ecology Chinese Academy of Sciences Shanghai 200032 China

Pluripotent stem cells are able to both self-renew and generate undifferentiated cells for the formation of new tissues and organs. In higher plants, stem cells found in the shoot apical meristem （SAM） and the root apical meristem （RAM） are origins of organogenesis occurring post-embryonically. It is important to understand how the regulation of stem cell fate is coordinated to enable the meristem to constantly generate different types of lateral organs. Much knowledge has accumulated on specific transcription factors controlling SAM and RAM activity. Here, we review recent evidences for a role of chromatin remodeling in the maintenance of stable expression states of transcription factor genes and the control of stem cell activity in Arabidopsis.

关键词： chromatin structure and remodeling epigenetics meristem development histone chaperone histone modification.