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Live Cell Imaging with R-GEC01 Sheds Light on fig22- and Chitin-Induced Transient [Ca2＋]cyt Patterns in Arabidopsis

Molecular Plant 2015年第8期8卷 1188-1200页

作者： Nana F. Keinath Rainer Waadt rik brugman Julian I. Schroeder Guido Grossmann Karin Schumacher Melanie Krebs Centre for Organismal Studies Plant Developmental Biology University of Heidelberg Im Neuenheimer Feld 230 69120 Heidelberg Germany Centre for Organismal Studies University of Heidelberg 69120 Heidelberg Germany Division of Biological Sciences Cell and Developmental Biology Section University of California San Diego 92093 La Jolla USA These authors contributed equally to this article.

Intracellular Ca2＋ transients are an integral part of the signaling cascade during pathogen-associated molecular pattern （PAMP）-triggered immunity in plants. Yet, our knowledge about the spatial distribution of PAMP-induced Ca2＋ signals is limited. Investigation of cell- and tissue-specific properties of Ca2＋- dependent signaling processes requires versatile Ca2＋ reporters that are able to extract spatial information from cellular and subcellular structures, as well as from whole tissues over time periods from seconds to hours. Fluorescence-based reporters cover both a broad spatial and temporal range, which makes them ideally suited to study Ca2＋ signaling in living cells. In this study, we compared two fluorescence-based Ca2＋ sensors： the F6rster resonance energy transfer （FRET）-based reporter yellow cameleon NES-YC3.6 and the intensity-based sensor R-GECO1. We demonstrate that R-GECO1 exhibits a significantly increased signal change compared with ratiometric NES-YC3.6 in response to several stimuli. Due to its superior sensitivity, R-GECO1 is able to report fig22- and chitin-induced Ca2＋ signals on a cellular scale, which allowed identification of defined [Ca2＋]cyt oscillations in epidermal and guard cells in response to the fungal elicitor chitin. Moreover, we discovered that fig22- and chitin-induced Ca2＋ signals in the root initiate from the elongation zone.

关键词： calcium imaging R-GECO1 fig22 chitin sensor Arabidopsis

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A Roadmap toward Engineered Nitrogen-Fixing Nodule Symbiosis

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Plant Communications 2020年第1期1卷 131-146页

作者： rik Huisman Rene Geurts Wageningen University Department of Plant SciencesLaboratory of Molecular BiologyDroevendaalsesteeg 1Wageningen 6708PBThe Netherlands

In the late 19th century,it was discovered that legumes can establish a root nodule endosymbiosis with nitrogen-fixing *** after,the question was raised whether it is possible to transfer this trait to non-leguminous *** the past century,an ever-increasing amount of knowledge provided unique insights into the cellular,molecular,and genetic processes controlling this *** addition,recent phylogenomic studies uncovered several genes that evolved to function specifically to control nodule formation and bacterial ***,despite this massive body of knowledge,the long-standing objective to engineer the nitrogen-fixing nodulation trait on nonleguminous crop plants has not been achieved *** this review,the unsolved questions and engineering strategies toward nitrogen-fixing nodulation in non-legume plants are discussed and highlighted.

关键词： nodulation legumes actinorhizal plants Parasponia engineering nitrogen fixation

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The unique structural and functional features of CXCL12

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Cellular & Molecular Immunology 2018年第4期15卷 299-311页

作者： rik Janssens Sofie Struyf Paul Proost Department of Microbiology and Immunology Rega Institute for Medical ResearchLaboratory of Molecular ImmunologyKU LeuvenUniversity of LeuvenLeuven B-3000Belgium

The CXC chemokine CXCL12 is an important factor in physiological and pathological processes, includingembryogenesis, hematopoiesis, angiogenesis and inflammation, because it activates and/or induces migration ofhematopoietic progenitor and stem cells, endothelial cells and most leukocytes. Therefore, CXCL12 activity istightly regulated at multiple levels. CXCL12 has the unique property of existing in six splice variants in humans,each having a specific tissue distribution and in vivo activity. Controlled splice variant transcription and mRNAstability determine the CXCL12 expression profile. CXCL12 fulfills its functions in homeostatic and pathologicalconditions by interacting with its receptors CXC chemokine receptor 4 (CXCR4) and atypical chemokine receptor 3(ACKR3) and by binding to glycosaminoglycans (GAGs) in tissues and on the endothelium to allow a properpresentation to passing leukocytes. Homodimerizaton and heterodimerization of CXCL12 and its receptors can altertheir signaling activity, as exemplified by the synergy between CXCL12 and other chemokines in leukocyte migrationassays. Receptor binding may also initiate CXCL12 internalization and its subsequent removal from theenvironment. Furthermore, CXCL12 activity is regulated by posttranslational modifications. Proteolytic removal ofNH2- or COOH-terminal amino acids, citrullination of arginine residues by peptidyl arginine deiminases or nitrationof tyrosine residues reduce CXCL12 activity. This review summarizes the interactions of CXCL12 with the cellularenvironment and discusses the different levels of CXCL12 activity regulation.

关键词： ACKR3 chemokine CXCL12 CXCR4 regulation

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Decision fusion-based approach for content-based image classification

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International Journal of Intelligent Computing and Cybernetics 2017年第3期10卷 310-331页

作者： Sudeep Thepade rik Das Saurav Ghosh Department of Information Technology Pimpri Chinchwad College of EngineeringPuneIndia Department of Information Technology Xavier Institute of Social ServiceRanchiIndia A.K.Choudhury School of Information Technology University of CalcuttaKolkataIndia

Purpose–Current practices in data classification and retrieval have experienced a surge in the use of multimedia *** of desired information from the huge image databases has been facing increased complexities for designing an efficient feature extraction *** approaches of image classification with text-based image annotation have faced assorted limitations due to erroneous interpretation of vocabulary and huge time consumption involved due to manual ***-based image recognition has emerged as an alternative to combat the aforesaid ***,exploring rich feature content in an image with a single technique has lesser probability of extract meaningful signatures compared to multi-technique feature ***,the purpose of this paper is to explore the possibilities of enhanced content-based image recognition by fusion of classification decision obtained using diverse feature extraction ***/methodology/approach–Three novel techniques of feature extraction have been introduced in this paper and have been tested with four different classifiers *** four classifiers used for performance testing were K nearest neighbor(KNN)classifier,RIDOR classifier,artificial neural network classifier and support vector machine ***,classification decisions obtained using KNN classifier for different feature extraction techniques have been integrated by Z-score normalization and feature scaling to create fusion-based framework of image *** has been followed by the introduction of a fusion-based retrieval model to validate the retrieval performance with classified *** works on content-based image identification have adopted fusion-based ***,to the best of the authors’knowledge,fusion-based query classification has been addressed for the first time as a precursor of retrieval in this ***–The proposed fusion techniques have successfull

关键词： Classification Information fusion Content-based feature extraction Retrieval

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Migration drivers in mountain regions in the context of climate change:A case study in Shangnan County of China

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Chinese Journal of Population,Resources and Environment 2013年第3期11卷 200-209页

作者： Yinru Lei Max Finlayson rik Thwaites Guoqing Shi Institution of Land Waterand SocietyCharles Sturt University National Research Center for Resettlement Hohai University

Climate change has become widely accepted as a challenge that humans will face in the not-too-distant *** ecosystems and their inhabitants are among the most vulnerable to climate *** paper seeks to explain migration drivers in specific mountain regions in the context of climate change based on Foresight's conceptual framework.A climate change sensitive field named Shangnan County in southern Shaanxi Province is chosen as the case study area to investigate local migration drivers.A series of qualitative research methods is employed in the case study including participant observation,semi-structured interviews,and focus group *** evidence of survey suggests that migration decisions are not only shaped by macro factors in aspects of environmental,economics,demographic,social,politics and psychological,but also influenced by placed-related barriers and facilitating mechanisms and personal characteristics.

关键词： climate change migration driver mountain region

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Public Charging Infrastructure in Germany–A Utilization and Profitability Analysis

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Journal of Modern Power Systems and Clean Energy 2022年第6期10卷 1750-1760页

作者： Benedict J.Mortimer Amandus Dominik Bach Christopher Hecht Dirk Uwe Sauer rik W.De Doncker Institute for Power Generation and Storage Systems at the E.ON Energy Research Center RWTH Aachen UniversityAachenGermany

The current increase in the number of electric vehicles in Germany requires an adequately developed charging *** numbers of public and semi-public charging stations are necessary to ensure sufficient coverage of charging *** order to make the installation worthwhile for the mostly private operators as well as public ones,a sufficient utilization is *** paper gives an overview of the differences in the utilization across the public charging infrastructure in *** this end,a dataset on the utilization of 21164 public and semi-public charging stations in Germany is *** installation and operating costs of various charging stations are modeled and economically evaluated in combination with the utilization *** is shown that in 2019-2020,the average utilization in Germany was rather low,albeit with striking regional *** consider future scenarios allowing the regional development forecasting of economic *** is demonstrated that a growth in electric mobility of 20%-30%per year leads to a large number of economically feasible charging parks in urban agglomeration areas.

关键词： Charging infrastructure charging station utilization electromobility economic analysis

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Characterization of the High-Strength Mg–3Nd–0.5Zn Alloy Prepared by Thermomechanical Processing

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Acta Metallurgica Sinica(English Letters) 2019年第3期32卷 321-331页

作者： Ji■í Kub■sek Drahomír Dvorsk■ Jozef Vesel■ Peter Min■rik M■ria Zemkov■ Dalibor Vojtěch Department of Metals and Corrosion Engineering Faculty of Chemical Technology University of Chemistry and Technology Prague Department of Physics of Materials Charles University

Magnesium alloys based on Nd and Zn are promising materials for both aviation industry and medical *** mechanical properties of these materials can be achieved by thermomechanical processing such as extrusion or rolling and by aging treatment, which can significantly strengthen the alloy. The question remains especially about the connection of texture strength created in the alloys based on the specific conditions of preparation. This work focuses on the Mg–3 Nd–0.5 Zn magnesium alloy prepared by hot extrusion of the as-cast state at two different temperatures combined with heat pre-treatment. Extrusion ratio of 16 and rate of 0.2 mm/s at 350 and 400 °C were selected for material preparation. The structures of prepared materials were studied by scanning electron microscopy and transmission electron microscopy. The effect of microstructure on mechanical properties was evaluated. Obtained results revealed the strong effect of thermal pre-treatment on final microstructure and mechanical properties of extruded materials. The Hall–Petch relation between grain size and tensile yield strength has been suggested in this paper based on the literature review and presented data. The observed behavior strongly supports the fact that the Hall–Petch of extruded Mg–3Nd–0.5 Zn alloys with different texture intensities cannot be clearly estimated and predicted. In addition, Hall–Petch relations presented in literature can be sufficiently obtained only for fraction of the Mg–3Nd–0.5 Zn alloys.

关键词： Mg–Nd–Zn alloys Extrusion Thermal treatment Microstructure Mechanical properties

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类玻璃碳材料的EELS分析

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稀有金属材料与工程 2007年第A2期36卷 757-759页

作者：张志力 rik Brydson Aidan Westwood Briand Rand 北京交通大学机电学院材料科学与工程研究所北京100044 英国利兹大学材料系材料研究所

探讨以酚醛树脂为前驱物的类玻璃碳,在不同温度炭化处理过程中的微孔变化情况,利用透射电子显微镜中的能量损失谱(EELS)技术,观察其显微结构与化学结构的变化。高分辨电镜观察发现,材料呈现微晶石墨碳层围绕微小孔洞结构排列的无定形结... 详细信息

探讨以酚醛树脂为前驱物的类玻璃碳,在不同温度炭化处理过程中的微孔变化情况,利用透射电子显微镜中的能量损失谱(EELS)技术,观察其显微结构与化学结构的变化。高分辨电镜观察发现,材料呈现微晶石墨碳层围绕微小孔洞结构排列的无定形结构,孔洞的形成主要是由小分子气化过程中产生的。由EELS图谱中的CK-edge分别对应于1s电子跃迁到π~*和σ~*反键轨道的两个特征峰,可计算得到C原子化学键SP^2杂化程度随炭化温度条件的不同有可观察到的比较明显的变化。

关键词：酚醛树脂无类玻璃碳 EELS

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Corrosion and mechanical properties of a novel biomedical WN43magnesium alloy prepared by spark plasma sintering

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Journal of Magnesium and Alloys 2021年第3期9卷 853-865页

作者： Michal Knapek Mária Zemková Adam Gres Eva Jablonská Frantisek Lukác Robert Král Jan Bohlen Peter Minárik Charles University Faculty of Mathematics and PhysicsKe Karlovu 512116 PragueCzech Republic Nuclear Physics Institute of CAS Řež13025068ŘežCzech Republic University of Chemistry and Technology Department of Biochemistry and MicrobiologyTechnická5Prague16628 PragueCzech Republic Institute of Plasma Physics of CAS Za Slovankou 318200 PragueCzech Republic Helmholtz-Zentrum Geesthacht Magnesium Innovation Centre(MagIC)D21502 GeesthachtGermany

Alloying of Mg with rare-earth(RE)elements proved to be beneficial for their in-vitro and in-vivo *** this work,a novel WN43(Mg-4 wt%Y-3 wt%Nd)alloy with a well-defined composition was prepared,where,unlike in the commercial WE43 alloy,the possibly harmful RE mischmetal was substituted by less toxic Nd.A modern spark plasma sintering(SPS)technique was used to effectively produce WN43 samples from atomized *** temperatures of 400℃-550℃ and holding times of 3 or 10 min were used and wellcompacted final materials were successfully *** was shown that a superior combination of corrosion and mechanical properties was attained in the samples sintered at 500℃ and 550℃,while the effect of sintering time was rather *** performance of this material was exceptional within the group of Mg alloys prepared by powder metallurgy and comparable with conventionally prepared ***,it was shown that a great variety of mechanical and corrosion characteristics can be obtained by altering the SPS parameters so as to fulfill case-specific requirements typical of biomedical ***,the novel WN43 alloy prepared by SPS seems to be a particularly suitable material for biomedical use.

关键词： Magnesium Biocompatibility Powder Sintering Corrosion Rare earth element

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The effect of powder size on the mechanical and corrosion properties and the ignition temperature of WE43 alloy prepared by spark plasma sintering

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Journal of Magnesium and Alloys 2021年第4期9卷 1356-1369页

作者： Drahomír Dvorský JiríKubásek Michaela Roudnická Filip Pruša David Necas Peter Minárik Jitka Stráská Dalibor Vojtech University of Chemistry and Technology Faculty of Chemical TechnologyDepartment of Metals and Corrosion EngineeringTechnická516628 Praha 6–DejvicePragueCzech Republic Institute of Physics Czech Academy of ScienceNa Slovance 1999/218221 Praha 8PragueCzech Republic Department of Physics of Materials Charles UniversityKe Karlovu 5Prague 12116Czech Republic

Powder metallurgy is a powerful method for the preparation of materials with superior *** work aimed to investigate the effect of powder size on the microstructure,mechanical,and corrosion properties of advanced WE43(Mg-4Y-3REE-Zr)alloy prepared by spark plasma sintering(SPS).At the same time,the effect of HF pre-treatment of the powder on the properties of final compacted products is *** powder particles yielded microstructure with more interfaces formed by Y_(2)O_(3),or MgF_(2) and YF_(3).These interfaces work as barriers against corrosion,which greatly improves corrosion *** suggested pre-treatment of powder in HF further reduced the corrosion rate of the compacted *** the contrary,fragile interfaces of YF_(3) decreased mechanical properties as the crack primarily propagates through these *** original powder containing the mixture of all powder fractions exerted the best combination of mechanical *** size has also shown to affect ignition *** highest ignition temperature was measured for the finest powder fraction.

关键词： Powder metallurgy Mechanical properties Corrosion Interface SPS

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