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topography modulates effects of nitrogen deposition on microbial resource limitation in a nitrogen-saturated subtropical forest

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Forest Ecosystems 2021年第4期8卷 914-922页

作者： Hao Chen Junjie Tang Xibin Sun Kayan Ma Huaihai Chen Dejun Li State Key Laboratory of Biocontrol School of EcologySun Yat-sen University510275 GuangzhouChina Key Laboratory of Agro-ecological Processes in Subtropical Region Institute of Subtropical AgricultureChinese Academy of Sciences410125 ChangshaHunanChina Huanjiang Observation and Research Station for Karst Ecosystems Institute of Subtropical AgricultureChinese Academy of Sciences547100 HuanjiangChina

Background:Nitrogen(N)saturation theory proposes that an ecosystem might switch from N limitation to carbon(C),phosphorus(P),or other nutrient limitations if it receives continuous N input.Yet,after N limitation is removed,which nutrient is the most limited and whether topography modulates such change is rarely tested at a microbial level.Here,we conducted a two-year N addition experiment under two different topography positions(i.e.a slope and a valley)in a N-saturated subtropical forest.Soil enzyme activity was measured,and ecoenzymatic stoichiometry indexes were calculated as indicators of microbial resource limitation.Results:In the valley,two-year N addition changed the activity of all studied enzymes to various degrees.As a result,microbial C limitation was aggravated in the valley,and consequently microbial decomposition of soil labile organic C increased,but microbial P limitation was alleviated due to the stoichiometry balance.On the slope,however,N addition did not significantly change the activity of the studied enzymes,and did not alter the status of microbial resource limitation.Conclusions:These results indicate that C is a more limited element for microbial growth than P after removing N limitation,but we also highlight that topography can regulate the effect of N deposition on soil microbial resource limitation in subtropical forests.These findings provide useful supplements to the N saturation theory.

关键词： Nitrogen deposition topography Nutrient limitation N saturation Enzyme activity Enzymatic stoichiometry

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Influence of topography on the fine structures of stratospheric gravity waves:An analysis using COSMIC-2 temperature data

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Earth and Planetary Physics 2024年第3期8卷 497-513页

作者： JiaRui Wei Xiao Liu JiYao Xu QinZeng Li Hong Gao State Key Laboratory of Space Weather National Space Science CenterChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China Institute of Electromagnetic Wave School of PhysicsHenan Normal UniversityXinxiang Henan 453000China

We derive the potential energy of gravity waves(GWs)in the upper troposphere and stratosphere at 45°S-45°N from December 2019 to November 2022 by using temperature profiles retrieved from the Constellation Observing System for Meteorology,Ionosphere,and Climate-2(COSMIC-2)satellite.Owing to the dense sampling of COSMIC-2,in addition to the strong peaks of gravity wave potential energy(GWPE)above the Andes and Tibetan Plateau,we found weak peaks above the Rocky,Atlas,Caucasus,and Tianshan Mountains.The land-sea contrast is responsible for the longitudinal variations of the GWPE in the lower and upper stratosphere.At 40°N/S,the peaks were mainly above the topographic regions during the winter.At 20°N/S,the peaks were a slight distance away from the topographic regions and might be the combined effect of nontopographic GWs and mountain waves.Near the Equator,the peaks were mainly above the regions with the lowest sea level altitude and may have resulted from convection.Our results indicate that even above the local regions with lower sea level altitudes compared with the Andes and Tibetan Plateau,the GWPE also exhibits fine structures in geographic distributions.We found that dissipation layers above the tropopause jet provide the body force to generate secondary waves in the upper stratosphere,especially during the winter months of each hemisphere and at latitudes of greater than 20°N/S.

关键词： topography fine structures stratospheric gravity waves Constellation Observing System for Meteorology Ionosphere and Climate-2(COSMIC-2) dissipation layers

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Synergistic stimulation of surface topography and biphasic electric current promotes muscle regeneration

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Bioactive Materials 2022年第5期7卷 118-129页

作者： Indong Jun Na Li Jaehee Shin Jaeho Park Young Jun Kim Hojeong Jeon Hyuk Choi Jae-Gu Cho Byoung Chan Choi Hyung-Seop Han Jae-Jun Song Environmental Safety Group Korea Institute of Science&Technology Europe(KIST-EUROPE)Saarbrücken66123Germany Department of Otorhinolaryngology-Head and Neck Surgery Korea University College of MedicineSeoul02841Republic of Korea Department of Medical Sciences Graduate School of MedicineKorea UniversitySeoul02841Republic of Korea Center for Biomaterials Biomedical Research InstituteKorea Institute of Science&Technology(KIST)Seoul02792Republic of Korea Laser Surface Texturing Group AYECLUSGyeonggi-do14255Republic of Korea

Developing a universal culture platform that manipulates cell fate is one of the most important tasks in the investigation of the role of the cellular microenvironment.This study focuses on the application of topographical and electrical field stimuli to human myogenic precursor cell(hMPC)cultures to assess the influences of the adherent direction,proliferation,and differentiation,and induce preconditioning-induced therapeutic benefits.First,a topographical surface of commercially available culture dishes was achieved by femtosecond laser texturing.The detachable biphasic electrical current system was then applied to the hMPCs cultured on laser-textured culture dishes.Laser-textured topographies were remarkably effective in inducing the assembly of hMPC myotubes by enhancing the orientation of adherent hMPCs compared with flat surfaces.Furthermore,electrical field stimulation through laser-textured topographies was found to promote the expression of myogenic regulatory factors compared with nonstimulated cells.As such,we successfully demonstrated that the combined stimulation of topographical and electrical cues could effectively enhance the myogenic maturation of hMPCs in a surface spatial and electrical field-dependent manner,thus providing the basis for therapeutic strategies.

关键词： topography Electrical field stimulation Femtosecond laser Human myogenic precursor cell Cell therapy

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A two-step three dimensional marine magnetotelluric inversion method with considering rugged seafloor topography:Synthetic studies

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Science China Earth Sciences 2023年第4期66卷 765-780页

作者： Pengfei LIANG Qingyun DI Changmin FU Ruo WANG Qihui ZHEN Zhe YUN Jiagang ZHANG CAS Engineering Laboratory for Deep Resources Equipment and Technology Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China Innovation Academy for Earth Science Chinese Academy of SciencesBeijing 100029China College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijing 100049China Exploration Surveying Institute of Baogang Group Baotou 014010China

Inversion of magnetotelluric(MT) responses has been used to explore the electrical conductivity distribution of the Earth’s interior. In three-dimensional(3-D) inversions, it is significant to use a good initial model, because final model obtained by most 3-D inversion methods is influenced by the initial model. Although uniform initial models are widely used in 3-D inversions, one-dimensional(1-D) initial models are alternatives, which could more appropriately represent the actual conductivity variations in the Earth’s interior. This study presents a two-step 3-D inversion method, especially for marine cases. This inversion method first concentrates on obtaining a 1-D initial model and then inverts for 3-D conductivity structures with it, in both of which the 3-D topography is carefully taken into consideration. This method was tested by synthetic models of different topography variations(depression-shaped, smoothly varying, channel-shaped and square-shaped plateau topography) and of heterogeneous layers with different checkerboard-type anomalies(sharp or smooth lateral conductivity variations) embedded in1-D model of depth-dependent conductivity. The comparisons were done about obtaining an initial model by the proposed method and that inverted from the corrected responses. The results of 3-D inversions by using the method of this study were also compared to that with different uniform initial models. Results of synthetic tests and comparisons were discussed by using directional information of newly introduced model-vector parameters. The performance and validity of this method was verified.It also revealed that some of the newly introduced model-vector parameters could be used to show the convergence of inversions and help to select inverse model.

关键词： Magnetotelluric Integral equation topography Inversion Convergence

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Quantitative analysis of peripheral retinal defocus checked by multispectral refraction topography in myopia among youth

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Chinese Medical Journal 2023年第4期136卷 476-478页

作者： Qing Zhao Xueli Du Ye Yang Yali Zhou Xinxin Zhao Xuebing Shan Yuxuan Meng Meng Zhang Department of Ophthalmology Fourth Hospital of Hebei Medical UniversityShijiazhuangHebei 050000China

To the Editor:Myopia is the most common refractive error and a major reason for visual impairment.The prevalence of myopia is increasing worldwide and is particularly high in Asian countries.It affects 80%to 90%of young people in some parts of East and Southeast Asia.[1]High myopia,which is more than-6.00 D,increases the possibility of visual impairment due to ocular complications caused by extended axial length(AL),which include posterior uveioma,retinal detachment,choroidal new vascularization,and so on.Thus,the prevention and control of myopia is a difficult and important public health issue that has attracted great attention from the World Health Organization and the Chinese government.

关键词： visual checked topography

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topography guiding the accelerated and persistently directional cell migration induced by vaccinia virus

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Chinese Chemical Letters 2020年第1期31卷 167-171页

作者： Cheng Wang Ji Wang Dandan Fu Qiong Yan Daiwen Pang Zhiling Zhang Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education) College of Chemistry and Molecular Sciences State Key Laboratory of Virology Wuhan University

The rapid transmission of vaccinia virus(VACV)in vivo is thought to be closely related to the cell migration induced by it.Cell migration involved in dynamic changes of cell-substrate adhesion and actin cytoskeleton organization,which can influence by the micro/nano-scale topographic structures that cells are naturally exposed to via contact guidance.However,migration behaviors of VACV-infected cells exposed to topographic cues are still unknown.Herein,we designed an open chip with microgrooved poly(dimethyl siloxane)(PDMS)substrate to explore the topography roles in VACV-induced cell migration.Differed from the random cell migration observed in traditional scratch assay on planar substrate,VACV-infected cells had a tendency to persistently migrate along the axis parallel to microgroove with increased velocity.Moreover,infected cells exhibited a dominant elongated protrusion aligned to the micro-grating axis compare to the shorter lamella extended in any direction on smooth substrate.Interestingly,the Golgi complex preferred to relocate behind the nucleus confined within the micro-grating axis in majority of infected migratory cells.The directional polarization of cells embodied in protrusion formation and Golgi reorientation was responsible for the directionally persistent migration behaviors induced by VACV on microgrooved substrate.Infected cells response to substrate topography,causing the actin-filled stretched protrusion containing numerous virions and accelerated movement is likely to facilitate direct and rapid spread of VACV.This work opens a window for us to understand the migration behaviors of infected cells in vivo,and also provides a cue for revealing the relationship between virus-induced cell migration and virus rapid spread.

关键词： Cell migration topography Vaccinia virus Cytoskeleton Contact guidance Micro-patterned substrate

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Fucoidan and topography modification improved in situ endothelialization on acellular synthetic vascular grafts

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生物活性材料(英文) 2023年第4期22卷 535-550页

作者： Yuan Yao Aung Moe Zaw Deirdre E.J.Anderson YeJin Jeong Joshua Kunihiro Monica T.Hinds Evelyn K.F.Yim Department of Chemical Engineering University of Waterloo200 University Avenue WestWaterlooONN2L 3G1Canada Department of Biomedical Engineering Oregon Health&Science UniversityPortlandOR97239USA Waterloo Institute for Nanotechnology University of Waterloo200 University Avenue WestWaterlooONN2L 3G1Canada Center for Biotechnology and Bioengineering University of Waterloo200 University Avenue WestWaterlooONN2L 3G1Canada

Thrombogenesis remains the primary failure of synthetic vascular grafts.Endothelial coverage is crucial to provide an antithrombogenic surface.However,most synthetic materials do not support cell adhesion,and transanastomotic endothelial migration is limited.Here,a surface modification strategy using fucoidan and topography was developed to enable fast in situ endothelialization of polyvinyl alcohol,which is not endothelial cell-adhesive.Among three different immobilization approaches compared,conjugation of aminated-fucoidan promoted endothelial monolayer formation while minimizing thrombogenicity in both in vitro platelet rich plasma testing and ex vivo non-human primate shunt assay.Screening of six topographical patterns showed that 2μm gratings increased endothelial cell migration without inducing inflammation responses of endothelial cells.Mechanistic studies demonstrated that fucoidan could attract fibronectin,enabling integrin binding and focal adhesion formation and activating focal adhesion kinase(FAK)signaling,and 2μm gratings further enhanced FAK-mediated cell migration.In a clinically relevant rabbit carotid artery end-to-side anastomosis model,60%in situ endothelialization was observed throughout the entire lumen of 1.7 mm inner diameter modified grafts,compared to 0%of unmodified graft,and the four-week graft patency also increased.This work presents a promising strategy to stimulate in situ endothelialization on synthetic materials for improving long-term performance.

关键词： Blood-contacting devices Small diameter vascular graft Endothelialization topography Fucoidan

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Effect of topography on the changes of Urumqi Glacier No.1 in the Chinese Tianshan Mountains

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Journal of Arid Land 2022年第7期14卷 719-738页

作者： LI Hongliang WANG Puyu LI Zhongqin JIN Shuang XU Chunhai MU Jianxin HE Jie YU Fengchen State Key Laboratory of Cryosphere Science Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China University of Chinese Academy of Sciences Beijing 100049China College of Sciences Shihezi UniversityShihezi 832000China College of Geography and Environmental Science Northwest Normal UniversityLanzhou 730070China

topography plays an important role in determining the glacier changes.However,topography has often been oversimplified in the studies of the glacier changes.No systematic studies have been conducted to evaluate the relationship between the glacier changes and topographic features.The present study provided a detailed insight into the changes in the two branches(east branch and west branch)of Urumqi Glacier No.1 in the Chinese Tianshan Mountains since 1993 and systematically discussed the effect of topography on the glacier parameters.This study analyzed comprehensive recently observed data(from 1992/1993 to 2018/2019),including mass balance,ice thickness,surface elevation,ice velocity,terminus,and area,and then determined the differences in the changes of the two branches and explored the effect of topography on the glacier changes.We also applied a topographic solar radiation model to analyze the influence of topography on the incoming shortwave radiation(SW_(in))across the entire glacier,focusing on the difference in the SW_(in) between the two branches.The glacier mass balance of the east branch was more negative than that of the west branch from 1992/1993 to 2018/2019,and this was mainly attributed to the lower average altitude of the east branch.Compared with the west branch,the decrease rate of the ice velocity was lower in the east branch owing to its relatively increased slope.The narrow shape of the west branch and its southeast aspect in the earlier period resulted in a larger glacier terminus retreat of the west branch.The spatial variability of the SW_(in) across the glacier surface became much larger as altitude increased.The SW_(in) received by the east branch was slightly larger than that received by the west branch,and the northern aspect could receive more SW_(in),leading to glacier melting.In the future,the difference of the glacier changes between the two branches will continue to exist due to their topographic differences.This work is fundamental to understanding how topographic features affec

关键词： glacier changes topography solar radiation glacier terminus retreat climate warming Urumqi Glacier No.1 Chinese Tianshan Mountains

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Bionic superhydrophobic surfaces based on topography of copper oxides

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Biosurface and Biotribology 2022年第3期8卷 199-211页

作者： Chen Chen Haiyang Zhan Xiangge Bai Zichao Yuan Lei Zhao Yahua Liu Shile Feng Key Laboratory for Precision&Non‐traditional Machining Technology of Ministry of Education Dalian University of TechnologyDalianChina

Superhydrophobic surfaces(SHSs)exist in many biological organisms endowed by spectacular surface topographies,which provide important insights to drive a paradigm shift in design of engineering surfaces.Based on this,extensive progresses have been developed on bionic superhydrophobic strategies.Among them,SHSs based on topography of copper oxides exhibit considerable application prospects because of the steerability and diversity of topography,as well as additional performances,such as antibiosis,anticorrosion and catalysis.We first present a brief overview of the discovery of natural SHSs as well as fundamental understanding of surface wetting performance.Then,the structural effects in superhydrophobic systems based on the topographies of biological organisms and copper oxides are described.Finally,we highlight the perspectives on the novel design strategies of copper oxide‐based SHSs that adapt to various practical applications.

关键词： biological organisms bionic SHSs copper‐oxides topography wetting

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Mutual comparative analysis:a new topography-guided custom ablation protocol referencing subjective refraction to modify corneal topographic data

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Eye and Vision 2020年第4期7卷 347-355页

作者： Kaiwei Cao Lina Liu Tao Zhang Ting Liu Ji Bai 77120 unit of People’s Liberation Army(PLA) No.1441 FengJu Ring RoadJinniu DistrictChengdu 610081China Chongqing vision institute No.77 Changjiang 2 RoadYuzhong DistrictChongqing 400042China Department of Ophthalmology Daping Hospital and the Research Institute of Surgery of the Army Medical University of PLANo.10 Changjiangzhi RoadYuzhong DistrictChongqing 400042China

Background:Several planning algorithms have been developed for topography-guided custom ablation treatment(T-CAT),but each has its own deficiencies.The purpose of this study is to demonstrate the potential of a novel mutual comparative analysis(MCA)informed by manifest refraction and corneal topographic data and the patient’s subjective perception in correcting ametropia.Methods:This retrospective review included patients with significant preoperative differences in the power or axis of astigmatism according to the manifest refraction and corneal topographic data(power>0.75 D and/or axis>10°).T-CAT planning was designed using MCA.Follow-ups were conducted for at least 6 months.Results:Seventy-nine patients(121 eyes)were included.The mean preoperative deviation in the astigmatic power and axis were 0.72±0.43 D and 20.18±23.68°,respectively.The average oculus residual astigmatism(ORA)was 0.81±0.32 D(range:0.08–1.66 D).Six months postoperatively,the mean spherical equivalent refraction was 0.04±0.42 D,and the mean cylinder was−0.27±0.24 D.The mean efficacy and safety indices were 1.10 and 1.15,respectively.The uncorrected distance visual acuity in 92%of the eyes was the same or better than the corrected distance visual acuity.The angle of error was±5°in 61%of eyes and±15°in 84%of eyes.Residual astigmatism was≤0.5 D in 91%of eyes.Optical quality and photopic contrast sensitivity did not change significantly(p>0.05),and the scotopic contrast sensitivity decreased at 3,6,and 12 cpd(p<0.05).The vertical coma and horizontal coma of the anterior corneal surface significantly decreased postoperatively but increased during follow-up.Conclusions:The MCA demonstrated safety,efficacy,accuracy,predictability,and stability and can be used as a complementary and feasible method for T-CAT.

关键词： Mutual comparative analysis topography-guided custom ablation treatment Astigmatism Manifest refraction topography

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