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Functional traits of poplar leaves and fine roots responses to ozone pollution under soil nitrogen addition

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Journal of Environmental Sciences 2022年第3期34卷 118-131页

作者： Pin Li Rongbin Yin Huimin Zhou Sheng Xu Zhaozhong Feng Research Center for Urban Forestry Key Laboratory for Forest Silviculture and Conservation of Ministry of EducationKey Laboratory for Silviculture and Forest Ecosystem Research in Arid-and Semi-arid Region of State Forestry AdministrationBeijing Forestry UniversityBeijing 100083China State Key Laboratory of Urban and Regional Ecology Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China Key Laboratory of Forest Ecology and Management Institute of Applied EcologyChinese Academy of SciencesShenyang 110016China Institute of Ecology Key Laboratory of Agrometeorology of Jiangsu ProvinceSchool of Applied MeteorologyNanjing University of Information Science and TechnologyNanjing 210044China

Concurrent ground-level ozone(O_(3))pollution and anthropogenic nitrogen(N)deposition can markedly influence dynamics and productivity in forests.Most studies evaluating the functional traits responses of rapid-turnover organs to O_(3) have specifically examined leaves,despite fine roots are another major source of soil carbon and nutrient input in forest ecosystems.How elevated O_(3) levels impact fine root biomass and biochemistry remains to be resolved.This study was to assess poplar leaf and fine root biomass and biochemistry responses to five different levels of O_(3) pollution,while additionally examining whether four levels of soil N supplementation were sufficient to alter the impact of O_(3) on these two organs.Elevated O_(3) resulted in a more substantial reduction in fine root biomass than leafbiomass;relative to leaves,more biochemically-resistant components were present within fine root litter,which contained high concentrations of lignin,condensed tannins,and elevated C:N and lignin:N ratios that were associated with slower rates of litter decomposition.In contrast,leaves contained more labile components,including nonstructural carbohydrates and N,as well as a higher N:P ratio.Elevated O_(3) significantly reduced labile components and increased biochemically-resistant components in leaves,whereas they had minimal impact on fine root biochemistry.This suggests that O_(3) pollution has the potential to delay leaf litter decomposition and associated nutrient cycling.N addition largely failed to affect the impact of elevated O_(3) levels on leaves or fine root chemistry,suggesting that soil N supplementation is not a suitable approach to combating the impact of O_(3) pollution on key functional traits of poplars.These results indicate that the significant differences in the responses of leaves and fine roots to O_(3) pollution will result in marked changes in the relative belowground roles of these two litter sources within forest ecosystems,and such changes will independently of nitrogen load.

关键词： Ozone pollution Nitrogen(N)input Fine roots Leaves Functional traits Chemical complexity

Coverage Analyses on Directional Transmissions Ultra-Dense Networks with Imperfect Beam Alignment

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China Communications 2022年第5期19卷 318-328页

作者： Yining xu sheng Zhou Beijing National Research Center for Information Science and Technology Department of Electronic EngineeringTsinghua UniversityBeijing 100084China

Blockage and imperfect beam alignment are two principal difficulties in high-frequency bands directional transmissions.In this paper,the coverage performance of downlink directional transmissions in ultra-dense networks is analyzed,with the consideration of beam alignment error and link blockage through stochastic geometry.Numerical experiments demonstrate that narrower beam leads to higher coverage probability with perfect beam alignment,but it is not the case with imperfect beam alignment.Therefore,the optimal beamwidth that maximize the coverage probability is characterized and a closed-form approximation of the optimal beamwidth is derived under imperfect beam alignment,accordingly.Furthermore,the optimal beamwidth is a monotonically increasing function of the standard deviation of the beam alignment error,and a monotonically decreasing function of the beamwidth of correspondent communication end,indicating that the beamwidth of the communication pairs ought to be jointly designed.

关键词： imperfect beam alignment directional transmission ultra-dense networks stochastic geometry

Prospects for the application of transcranial magnetic stimulation in diabetic neuropathy

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Neural Regeneration Research 2021年第5期16卷 955-962页

作者： Xi xu Dong-Sheng Xu Department of Rehabilitation Medicine Affiliated Hospital of Nantong UniversityNantongJiangsu ProvinceChina Department of Rehabilitation Medicine Yueyang Hospital of Integrated Traditional Chinese and Western MedicineShanghaiChina School of Rehabilitation Science Shanghai University of Traditional Chinese MedicineShanghaiChina

Encouraging results have been reported for the use of transcranial magnetic stimulationbased nerve stimulation in studies of the mechanisms of neurological regulation,nerve injury repair,and nerve localization.However,to date,there are only a few reviews on the use of transcranial magnetic stimulation for diabetic neuropathy.Patients with diabetic neuropathy vary in disease progression and show neuropathy in the early stage of the disease with mild symptoms,making it difficult to screen and identify.In the later stage of the disease,irreversible neurological damage occurs,resulting in treatment difficulties.In this review,we summarize the current state of diabetic neuropathy research and the prospects for the application of transcranial magnetic stimulation in diabetic neuropathy.We review significant studies on the beneficial effects of transcranial magnetic stimulation in diabetic neuropathy treatment,based on the outcomes of its use to treat neurodegeneration,pain,blood flow change,autonomic nervous disorders,vascular endothelial injury,and depression.Collectively,the studies suggest that transcranial magnetic stimulation can produce excitatory/inhibitory stimulation of the cerebral cortex or local areas,promote the remodeling of the nervous system,and that it has good application prospects for the localization of the injury,neuroprotection,and the promotion of nerve regeneration.Therefore,transcranial magnetic stimulation is useful for the screening and early treatment of diabetic neuropathy.transcranial magnetic stimulation can also alleviate pain symptoms by changing the cortical threshold and inhibiting the conduction of sensory information in the thalamo-spinal pathway,and therefore it has therapeutic potential for the treatment of pain and pain-related depressive symptoms in patients with diabetic neuropathy.Additionally,based on the effect of transcranial magnetic stimulation on local blood flow and its ability to change heart rate and urine protein content,transcranial magnetic stimulation has potentia

关键词： autonomic neuropathy central nervous system depression inflammation oxidative stress pain peripheral nerve plasticity recovery regeneration vascular

Electrochemical Mono-Deuterodefluorination of Trifluoromethyl Aromatic Compounds with Deuterium Oxide

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CCS Chemistry 2024年第1期6卷 230-240页

作者： Jie sheng xu Cheng Institute of Chemistry and Biomedical Sciences Jiangsu Key Laboratory of Advanced Organic MaterialsSchool of Chemistry and Chemical EngineeringNanjing UniversityNanjing 210023 State Key Laboratory of Elemento-Organic Chemistry Nankai UniversityTianjin 30071

The deuterodifluoromethyl group CF_(2)D combines the structural features of CF_(3) and CD_(3) groups,finding wide applications in diverse pharmaceutical entities.In this work,the electrochemical monodeuterodefluorination of Ar-CF_(3) to Ar-CF_(2)D is achieved with an unreported deuterium atom transfer-coupled electron transfer pathway using D_(2)O as the only D source for the first time.A series of Ar-CF_(3) substances,including commercial pharmaceuticals,were converted to corresponding CF_(2)D products in up to 91% yield and 97% D-incorporation.A variety of functional groups,including pyridine,pyrrole,furan,thiophene,borate,thio ether,amine,amide,sulfonamide,and halide,are well tolerated in this protocol.t-BuOLi was an essential reagent to achieve chemoselective mono-defluorination.

关键词： electrochemistry C-F activation fluorinecontaining drugs deuterated drugs deuterium oxide

Obstacle avoidance in human-robot cooperative transportation with force constraint

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Science China(Information Sciences) 2023年第1期66卷 334-335页

作者： Ying ZHANG Chenguang YANG Sheng Xu Yongsheng OU College of Automation Science and Engineering South China University of Technology Guangdong Provincial Key Lab of Robotics and Intelligent System Shenzhen Institutes of Advanced TechnologyChinese Academy of Sciences

Dear editor,Robots are often conceived as human-like machines that can interact with humans naturally and safely. Human-robot interaction means that robots can communicate with people,understand their needs, and act accordingly [1]. This interaction is critical when two people are needed to finish a task cooperatively.

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A Thermodynamic Perspective on Polymer Glass Formation

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Chinese Journal of Polymer Science 2023年第9期41卷 1329-1341,I0004页

作者： Wen-Sheng Xu Zhao-Yan Sun State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun130022China

The dynamics of polymeric and other glass-forming liquids dramatically slows down upon cooling toward the glass transition temperature without any obvious significant change in their static structure.A quantitative understanding of this extraordinary dynamic slowdown remains one of the most significant challenges in condensed matter physics.Historically,extensive efforts have been devoted to explaining the dynamics of glass-forming liquids in terms of thermodynamic properties,leading to a number of semi-empirical models emphasizing distinct thermodynamic properties.Here,a thermodynamic perspective is provided on the glass formation of polymeric and other materials.We begin with an overview of the thermodynamic models of glass formation,including the intuitively appealing“free volume”models,enthalpy models originally emphasized by Goldstein and later by others,and the highly influential configurational entropy-based models.The review of these models is followed by a discussion of the advances that attempt to bring together some of the seemingly disparate thermodynamic viewpoints on glass formation by revealing a close interrelation between thermodynamic properties.We conclude this review with remarks on several key topics in this field,along with our viewpoint for future work.

关键词： Glass formation Entropy Free volume Enthalpy

Memory-boosting RNN with dynamic graph for event-based action recognition

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Optoelectronics Letters 2023年第10期19卷 629-634页

作者： CHEN Guanzhou LIU sheng xu Jingting College of Computer Science and Technology Zhejiang University of TechnologyHangzhou310023China

Existing action recognition methods based on event cameras have not fully exploited the advantages of event cameras,such as compressing event streams into frames for subsequent calculation,which greatly sacrifices the time information of event streams.Meanwhile,the conventional PointCloud-based methods suffer from large computational complexity while processing event data,which make it difficult to handle long-term actions.To tackle the above problems,we propose a dynamic graph memory-boosting recurrent neural network(DG-MBRNN).The proposed DG-MBRNN splits the event stream into sequential graph data for preserving structural information,then uses the recurrent neural network(RNN)with boosting spatiotemporal memory to handle long-term sequences of actions.In addition,the proposed method introduces a dynamic reorganization mechanism for the graph based on the distances of features,which can effectively increase the ability to extract local features.In order to cope with the situation that the existing datasets have too simple actions and too limited categories,we propose a new event-based dataset containing 36 complex actions.This dataset will greatly promote the development of event-based action recognition research.Experimental results show the effectiveness of the proposed method in completing the event-based action recognition task.

关键词： boosting action dynamic

Catalytic asymmetric silicon-carbon bond-forming transformations based on Si–H functionalization

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Science China Chemistry 2023年第6期66卷 1654-1687页

作者： Li Li Wei-sheng Huang Zheng xu Li-Wen xu China Key Laboratory of Organosilicon Chemistry and Material Technology of Ministry of Education Key Laboratory of Organosilicon Material Technology of Zhejiang ProvinceCollege of MaterialChemistry and Chemical EngineeringHangzhou Normal UniversityHangzhou 311121China State Key Laboratory for Oxo Synthesis and Selective Oxidation Suzhou Research InstituteLanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou 730000China

In view of the exciting advancement on silicon–carbon bond-forming transformations achieved in the past decade,this review intends to show a unified illustration of the recent findings on enantioselective Si–H bond functionalization aided by asymmetric catalysis.Accordingly,this review describes the enantioselective silicon–carbon bond-forming Si–H bond functionalization,focusing on the reactivity and stereoselectivity in catalytic asymmetric hydrosilylation,carbene Si–H insertion,C–H silylation,and Si–C bond-forming cross-coupling reactions that were achieved with high enantioselectivity in the presence of transitionmetal catalyst systems.This review highlights recent and representative examples of the enantioselective Si–H bond functionalization,discusses the origins of silicon-involving stereoselectivities,and evaluates the substrate scopes and limitations in these catalytic asymmetric Si–H bond functionalization reactions due to the special reactivity of different hydrosilanes.

关键词： Si-H functionalization hydrosilylation C-H silylation carbene Si-H insertion asymmetric catalysis

A Semi-Looped-Functional for Stability Analysis of Sampled-Data Systems

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IEEE/CAA Journal of Automatica Sinica 2023年第5期10卷 1332-1335页

作者： Zhaoliang sheng Chong Lin shengyuan xu the Institute of Complexity Science Shandong Key Laboratory of Industrial Control Technologythe School of AutomationQingdao UniversityQingdao 266071 the School of Automation Nanjing University of Science and TechnologyNanjing 210094China

Dear Editor, In recent decades, owing to the significance of sampled-data control way on reducing the burden of communication transmission and improving the control capability of networked control systems, the researc... 详细信息

关键词： network communication Functional