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On the Normalized Laplacian Spectral Radius of Traceable Graphs

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Journal of Mathematical Research with Applications 2024年第3期44卷 291-303页

作者： yafei zhang Fei WEN Yonglei CHEN Institute of Applied Mathematics Lanzhou Jiaotong University

In this paper, we give some sufficient conditions for a graph to be traceable in terms of its order and size. As applications, the normalized Laplacian spectral conditions for a graph to be traceable are established.

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First Record of Cyclocarya from the Early Oligocene Qaidam Basin,North Tibet:Implications for the Paleogeography and Paleoecology

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Journal of Earth Science 2024年第1期35卷 201-211页

作者： yafei Hou Bowen Song Xiangchuan Li Fang Han Xu zhang Kexin zhang Institute of Geological Survey China University of GeosciencesWuhan 430074China Faculty of Materials Science and Chemistry China University of GeosciencesWuhan 430074China State Key Laboratory of Biogeology and Environmental Geology China University of GeosciencesWuhan 430074China College of Earth Sciences and Resources&Key Laboratory of Western Mineral Resources and Geological Engineering of the Ministry of Education Chang'an UniversityXi'an 710054China State Key Laboratory of Palaeobiology and Stratigraphy Nanjing Institute of Geology and PalaeontologyChinese Academy of SciencesNanjing 210008China School of Earth Sciences East China University of TechnologyNanchang 330013China

As the largest intermontane basin in the northeastern Tibetan Plateau(TP),the Qaidam Basin provides unique insight into paleoclimatic change and its relationship with global change and uplift on the TP.In this study,based on morphological comparison,fossil fruit of Cyclocarya from the Early Oligocene Shangganchaigou Formation in the Qaidam Basin is assigned as Cyclocarya cf.weylandii.The discovery of Cyclocarya cf.weylandii demonstrates the occurrence of Cyclocarya in the Oligocene sediment in Qaidam Basin.This is the first record of Cyclocarya fossil of Early Oligocene Age in China and indicates that Cyclocarya has existed on the northeastern TP since at least the Early Oligocene.The living analogues of the current fossil now lives in sub-tropical China,where the East Asian Monsoon is prevalent.Integrating the new fossils and previously reported fossil remains of plants and fishes,it can be inferred that the Early Oligocene Qaidam Basin was primarily influenced by westerly circulation and had a relatively warm and humid climate,which was in sharp contrast to the present-day climate in Qaidam Basin.

关键词： biostratigraphy climate change winged-fruit fossil Qaidam Basin Early Oligocene paleoclimate paleogeography

C_(60) as a metal-free catalyst for lithium-oxygen batteries

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Nano Research 2024年第5期17卷 3982-3987页

作者： Xinxin zhang Jiaming Tian Yu Wang Shaohua Guo yafei Li Jiangsu Collaborative Innovation Centre of Biomedical Functional Materials School of Chemistry and Materials ScienceNanjing Normal UniversityNanjing 210023China College of Engineering and Applied Sciences Jiangsu Key Laboratory of Artificial Functional MaterialsNational Laboratory of Solid State MicrostructuresCollaborative Innovation Center of Advanced MicrostructuresFrontiers Science Center for Critical Earth Material CyclingNanjing UniversityNanjing 210023China

Carbon materials have shown significant potential as catalysts for lithium-oxygen batteries(LOBs).However,the intrinsic carbon sites are typically inert,necessitating extensive modifications and resulting in a limited density of active sites.Here we present C_(60) as a metal-free cathode catalyst for LOBs,using density functional theory calculations and experimental verifications.The lithiation reactions on the pristine carbon sites of C_(60) are energetically favorable due to its curvedπ-conjugation over the pentagon-hexagon networks.The kinetic analysis specifically reveals low energy barriers for Li_(2)O_(2) decomposition and Li diffusion on C_(60).Consequently,C_(60) exhibits significantly higher catalytic activity than typical carbon materials such as graphene and carbon nanotubes.Our electrochemical measurements validate the predictions,notably demonstrating that the intrinsic activity of C_(60) is comparable to that of noble metals.

关键词： lithium-oxygen batteries C_(60) density functional theory(DFT)calculations metal-free cathode

Comprehensive evaluation and spatial-temporal evolution characteristics of urban resilience in Chengdu-Chongqing Economic Circle

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Chinese Journal of Population,Resources and Environment 2024年第1期22卷 58-67页

作者： Xin Li Shuyi zhang Rongxi Ren yafei Wang School of Economics and Management Chongqing Normal UniversityChongqing 401331China College of Marxism Taiyuan Normal UniversityTaiyuan 030619China Family Institute Northwestern UniversityChicago 60208USA

To clarify the connotations and extensions of urban resilience,this study focuses on the Chengdu-Chongqing Economic Circle with 16 cities as research subjects.A comprehensive evaluation index system was constructed to measure the resilience of each city from 2003 to 2020.The spatial-temporal evolution characteristics were analyzed using Kernel density estimation,standard deviation ellipse,and spatial Markov chain analysis,and the spatial Tobit model was introduced to discover the influencing factors.The results indicate the following:①Urban resilience in the Chengdu-Chongqing Economic Circle displays an upward trend,with the center of gravity moving to the southwest,and the polarization phenomenon intensifying.②The urban resilience level in a region has certain spatial and geographical dependence,while the probability of urban resilience transfer differs in adjacent cities with different resilience levels.③Urban centrality,economic scale,openness level,and financial development promote urban resilience,whereas government scale significantly inhibits it.Finally,this paper proposes countermeasures and suggestions to improve the urban resilience of the Chengdu-Chongqing Economic Circle.

关键词： Chengdu-chongqing Economic Circle Urban resilience Spatial-temporal evolution Driving factor

Decabromodiphenyl ether induces the chromosome association disorders of spermatocytes and deformation failures of spermatids in mice

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Journal of Environmental Sciences 2024年第4期138卷 531-542页

作者： Jinglong Xue Xiangyang Li yafei Chi Leqiang Gao Yue zhang Yan Wang Moxuan Zhao Jialiu Wei Zhixiong Shi Xianqing Zhou Department of Toxicology and Hygienic Chemistry School of Public HealthCapital Medical UniversityBeijing 100069China Beijing Key Laboratory of Environmental Toxicology Capital Medical UniversityBeijing 100069China Laboratory Animal Center Capital Medical UniversityBeijing 100069China Key Laboratory of Cardiovascular Epidemiology&Department of Epidemiology Fuwai HospitalNational Center for Cardiovascular DiseasesChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijing 100037China

The environmental presence of decabromodiphenyl ether(BDE-209),which is toxic to the male reproductive system,is widespread.The current study investigated its mechanism of toxicity in mice.The results showed,that BDE-209 induced DNA damage,decreased the expression of the promoter of meiosis spermatogenesis-and oogenesis-specific basic helix-loop-helix 1(Sohlh1),meiosis related-factors Lethal(3)malignant brain tumor like 2(L3MBTL2),PIWI-like protein 2(MILI),Cyclin-dependent kinase 2(CDK2),Cyclin A,synaptonemal complex protein 1(SYCP1)and synaptonemal complex protein 3(SYCP3),and caused spermatogenic cell apoptosis,resulting in a decrease in sperm quantity and quality.Furthermore,BDE-209 downregulated the levels of anaphase-promoting complex/cyclosome(APC/C),increased the expression of PIWI-like protein 1(MIWI)in the cytoplasm of elongating spermatids,and decreased the nuclear levels of RING finger protein 8(RNF8),ubiquitinated(ub)-H2A/ub-H2B,and Protamine 1(PRM1)/Protamine 2(PRM2),while increasing H2A/H2B nuclear levels in spermatids.The reproductive toxicity was persistent for 50 days following the withdrawal of BDE-209 exposure.The results suggested that BDE-209 inhibits the initiation of meiosis by decreasing the expression of Sohlh1.Furthermore,the reduced expression of L3MBTL2 inhibited the formation of chromosomal synaptonemal complexes by depressing the expression of meiosis regulators affecting the meiotic progression and also inhibited histone ubiquitination preventing the replacement of histones by protamines,by preventing RNF8 from entering nuclei,which affected the evolution of spermatids into mature sperm.

关键词： BDE-209 Meiosis L3MBTL2 Sperm RNF8 Histone ubiquitination

Comparative transcriptome analysis between rhesus macaques(Macaca mulatta) and crab-eating macaques(M. fascicularis)

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Zoological Research 2024年第2期45卷 299-310页

作者： Yu-Xiang Mao Yamei Li Zikun Yang Ning Xu Shilong zhang Xuankai Wang Xiangyu Yang Qiang Sun yafei Mao Institute of Neuroscience State Key Laboratory of NeuroscienceCenter for Excellence in Brain Science&Intelligence TechnologyChinese Academy of SciencesShanghai 200031China Shanghai Center for Brain Science and Brain-Inspired Intelligence Technology Shanghai 201210China University of Chinese Academy of Sciences Beijing 100049China Key Laboratory of Genetic Evolution&Animal Models Chinese Academy of SciencesKunmingYunnan 650201China Bio-X Institutes Key Laboratory for the Genetics of Developmental and Neuropsychiatric DisordersMinistry of EducationShanghai Jiao Tong UniversityShanghai 200030China Zhiyuan College Shanghai Jiao Tong UniversityShanghai 200240China Center for Genomic Research International Institutes of MedicineFourth Affiliated HospitalZhejiang UniversityYiwuZhejiang 322000China

Understanding gene expression variations between species is pivotal for deciphering the evolutionary diversity in phenotypes. Rhesus macaques(Macaca mulatta, MMU)and crab-eating macaques(M. fascicularis, MFA) serve as crucial nonhuman primate biomedical models with different phenotypes. To date, however, large-scale comparative transcriptome research between these two species has not yet been fully explored. Here, we conducted systematic comparisons utilizing newly sequenced RNA-seq data from84 samples(41 MFA samples and 43 MMU samples)encompassing 14 common tissues. Our findings revealed a small fraction of genes(3.7%) with differential expression between the two species, as well as 36.5% of genes with tissue-specific expression in both macaques. Comparison of gene expression between macaques and humans indicated that 22.6% of orthologous genes displayed differential expression in at least two tissues. Moreover,19.41% of genes that overlapped with macaque-specific structural variants showed differential expression between humans and macaques. Of these, the FAM220A gene exhibited elevated expression in humans compared to macaques due to lineage-specific duplication. In summary,this study presents a large-scale transcriptomic comparison between MMU and MFA and between macaques and humans. The discovery of gene expression variations not only enhances the biomedical utility of macaque models but also contributes to the wider field of primate genomics.

关键词： Crab-eating macaques Rhesus macaques Comparative transcriptomics Biomedical models Nonhuman primates RNA-seq Duplicated genes

Chemotherapy suppresses SHH gene expression via a specific enhancer

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Journal of Genetics and Genomics 2023年第1期50卷 27-37页

作者： yafei zhang Jianqiong Lin Kaibin Yang Zhicao Yue Department of Cell Biology and Medical Genetics International Cancer Centerand Guangdong Key Laboratory for Genome Stability and Disease PreventionShenzhen University Medical SchoolShenzhenGuangdong 518060China

Sonic hedgehog(SHH)signaling is a key regulator of embryonic development and tissue homeostasis that is involved in gastrointestinal(GI)cancer progression.Regulation of SHH gene expression is a paradigm of long-range enhancer function.Using the classical chemotherapy drug 5-fluorouracil(5FU)as an example,here we show that SHH gene expression is suppressed by chemotherapy.SHH is downstream of immediate early genes(IEGs),including Early growth response 1(Egr1).A specific 139 kb upstream enhancer is responsible for its down-regulation.Knocking down EGR1 expression or blocking its binding to this enhancer renders SHH unresponsive to chemotherapy.We further demonstrate that down-regulation of SHH expression does not depend on 5FU’s impact on nucleotide metabolism or DNA damage;rather,a sustained oxidative stress response mediates this rapid suppression.This enhancer is present in a wide range of tumors and normal tissues,thus providing a target for cancer chemotherapy and its adverse effects on normal tissues.We propose that SHH is a stress-responsive gene downstream of IEGs,and that traditional chemotherapy targets a specific enhancer to suppress its expression.

关键词： Sonic hedgehog Chemotherapy Immediate early genes EGR1 5-Fluorouracil

A modified streamwise body force model of fan with distorted inflow for rapid propulsion-airframe integrated simulation

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Chinese Journal of Aeronautics 2023年第12期36卷 202-213页

作者： Zhiping LI yafei zhang Tianyu PAN Jian zhang National Key Laboratory of Science and Technology on Aero-Engine Aero-Thermodynamics Beihang UniversityBeijing 100191China Research Institute of Aero-Engine Beihang UniversityBeijing 100191China School of Energy and Power Engineering Beihang UniversityBeijing 100191China

Streamwise Body Force Model(SBFM)could be used to simulate the force of blade on the airflow,resulting in rapid propulsion-airframe integrated simulation.However,when subjected to inlet distortion,the upstream flow field of fan stage is redistributed,which causes inaccurate prediction of fan stage performance.As inspired by the upstream influence of compressor,this paper aims to present a modification strategy for SBFM method to predict the compressor performance under circumferential inlet distortion without any knowledge of compressor geometry.Based on the linearized motion equation,the Upstream Influence Model(UIM)is introduced to predict the upstream flow field redistribution.Then the theoretical Mach number at Aerodynamic Interface Plane(AIP)position is calculated and selected to determine the corresponding body force coefficients based on the functional relationship between body force coefficients and Mach number,thus the upstream influence of compressor could be accurately quantified and the Modified Streamwise Body Force Model(MSBFM)could be established.Two studied cases are calculated with different methods and the upstream flow fields are analyzed.The prediction error of MSBFM method for compressor adiabatic efficiency is less than 3%,and the calculation efficiency is improved 20 times under the condition of ensuring computing accuracy.The MSBFM method has the potential for rapid propulsion-airframe integrated simulation.

关键词： Integrated simulation Streamwisebody force model Circumferential inletdistor-tion Upstream influence model Compressorperformance

Stability analysis of a slope containing water-sensitive mudstone considering different rainfall conditions at an open-pit mine

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International Journal of Coal Science & Technology 2023年第4期10卷 233-253页

作者： Guoyu Yang Yanlong Chen Xuanyu Liu Ri Yang yafei zhang Jialong zhang State Key Laboratory for Geomechanics and Deep Underground Engineering China University of Mining and TechnologyXuzhou 221116China School of Mines China University of Mining and TechnologyXuzhou 221116China Harwusu Open-Pit Mine China Shenhua Energy Co.LtdOrdos 010300China China Energy Investment Beidian Shengli Energy Co. LtdXinlinhot 026000China School of Mechanics and Civil Engineering China University of Mining and TechnologyXuzhou 221116China

Mudstone, as a typical soft rock with wide distribution, has been endangering the slopes containing mudstone by its watersensitivity of swelling and weakening strength when encountering water. To comprehensively understand the water-sensitivity of mudstone and reveal its infuence on slope stability, we took the working slope containing water-sensitive mudstone of Shengli No.1 open-pit coal mine in Xilinhot, Inner Mongolia, China, as an example. Mudstone samples taken from the working slope were remodeled and saturated, and then triaxial tested to obtain the efective cohesion and efective internal friction angle. The flter paper method was used to obtain the soil–water characteristic curve of unsaturated mudstone. The pore structure of mudstone samples with diferent water contents were analyzed using the mercury intrusion porosimetry tests combined with the fractal dimension. The total pore content of the mudstone sample with lower water content is greater than that of the mudstone sample with higher water content. The mesopores are more in the mudstone sample with lower water content, while the small pores are more in the mudstone sample with higher water content. The variation of water content will change the complexity of mudstone pore structure. The higher the water content, the simpler the mudstone pore structure and the smoother the pore surface. Numerical calculations were conducted on the stability of the working slope under diferent rainfall conditions. The efective saturation on the mudstone layer surface changed and the plastic strain all occurred on the mudstone steps under diferent rainfall conditions. The key to preventing landslide of the slope containing water-sensitive mudstone in Shengli No.1 open-pit coal mine is to control the deformation and sliding of the mudstone layer.

关键词： Water-sensitivity SWCC Pore structure Rainfall infltration Slope stability