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Ratchet motion and current motors in pulsating reversal of coupled Brownian symmetric potentials

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Frontiers of physics 2017年第4期12卷 197-206页

作者： chen-pu li Hong-Bin chen Zhi-Gang Zheng Department of Physics Beijing Normal University Beijing 100875 China College of Science Hebei University of Architecture Zhangjiakou 075000 China Institute of Systems Science (ISS) Huaqiao University Xiamen 361021 China College of Information Science and Engineering Huaqiao University Xiamen 361021 China

In this study, we investigate the collective directed transport of coupled Brownian particles in spatially symmetric periodic potentials under time-periodic pulsating modulations. We find that the coupling between two particles can induce symmetry breaking and consequently collective directed motion. Moreover, the direction of motion can be reversed under certain conditions. The dependence of directed current on various parameters is systematically studied, reverse motion can be achieved by modulating the coupling free length and the phase shift of tile pulsating potential. The dynamical mechanism of these transport properties is understood in terms of the effective-potential theory and the space-time transformation invariance. The directed transport of coupled Brownian motors can be maniplflated and optimized by adjusting the coupling strength, pulsating frequency, or noise intensity.

关键词： coupled Brownian motors ratchet effective potential symmetric periodic potential noise

Rotation-translation coupling of a double-headed Brownian motor in a traveling-wave potential

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Frontiers of physics 2021年第3期16卷 165-175页

作者： Wei-Xia Wu chen-pu li Yan-li Song Ying-Rong Han Zhi-Gang Zheng Science Education Department Beijing Institute of Graphic CommunicationBeijing102600China College of Science Hebei University of ArchitectureZhangjiakou075000China School of Science Tianjin UniversityTianjin300072China School of Science Hebei University of TechnologyTianjin300401China Institute of Systems Science and College of Information Science and Engineering Huaqiao UniversityXiamen361021China

Considering a double-headed Brownian motor moving with both translational and rotational degrees of freedom,we investigate the directed transport properties of the system in a traveling-wave *** is found that the traveling wave provides the essential condition of the directed transport for the system,and at an appropriate angular frequency,the positive current can be optimized.A general current reversal appears by modulating the angular frequency of the traveling wave,noise intensity,external driving force and the rod *** transforming the dynamical equation in traveling-wave potential into that in a tilted potential,the mechanism of current reversal is *** both cases of Gaussian and Lévy noises,the currents show similar dependence on the ***,the current in the tilted potential shows a typical stochastic resonance *** external driving force has also a resonance-like effect on the current in the tilted *** the current in the traveling-wave potential exhibits the reverse behaviors of that in the tilted ***,the currents obviously depend on the stability index of the Lévy noise under certain conditions.

关键词： Brownian motor rotation-translation coupling traveling-wave potential current reversal

Directed transport of coupled Brownian motors in a two-dimensional traveling-wave potential

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Chinese Physics B 2020年第9期29卷 244-248页

作者： Wei-Xia Wu Zhi-Gang Zheng Yan-li Song Ying-Rong Han Zhi-cheng Sun chen-pu li Science Education Department Beijing Institute of Graphic CommunicationBeijing 102600China Institute of Systems Science and College of Information Science and Engineering Huaqiao UniversityXiamen 361021China School of Science Tianjin UniversityTianjin 300072China School of Science Hebei University of TechnologyTianjin 300401China School of Printing and Packaging Engineering Beijing Institute of Graphic CommunicationBeijing 102600China College of Science Hebei Institute of Architecture and Civil EngineeringZhangjiakou 075000China

Considering an elastically coupled Brownian motors system in a two-dimensional traveling-wave potential, we investigate the effects of the angular frequency of the traveling wave, wavelength, coupling strength, free length of the spring, and the noise intensity on the current of the system. It is found that the traveling wave is the essential condition of the directed transport. The current is dominated by the traveling wave and varies nonmonotonically with both the angular frequency and the wavelength. At an optimal angular frequency or wavelength, the current can be optimized. The coupling strength and the free length of the spring can locally modulate the current, especially at small angular frequencies. Moreover, the current decreases rapidly with the increase of the noise intensity, indicating the interference effect of noise on the directed transport.

关键词： directed transport Brownian motors coupled system two-dimensional traveling-wave potential

Depression of the Thoracolumbar Posterior Vertebral Body on the Estimation of Cement Leakage in Vertebroplasty and Kyphoplasty Operations

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Chinese Medical Journal 2015年第23期128卷 3158-3162页

作者： Hao chen pu Jia li Bao Fei Feng He Yang Jin-Jun li Hai Tang Department of Orthopaedics Beijing Friendship Hospital Capital Medical University Beijing 100050 China

Background： The cross-section ofthoracolumbar vertebral body is kidney-shaped with depressed posterior boundary. The anterior wall of the vertebral canal is separated from the posterior wall of the vertebral body on the lateral X-ray image. This study was designed to determine the sagittal distance between the anterior border of the vertebral canal and the posterior border of the vertebral body （DBCV） and to analyze the potential role of DBCV in the estimation of cement leakage during percutaneous vertebroplasty （PVP） or percutaneous kyphoplasty （PKP）. Methods： We retrospectively recruited 233 patients who had osteoporotic vertebral compression fractures and were treated with PVP or PKP. Computed tomography images of T11-L2 normal vertebrae were measured to obtain DBCV. The distance from cement to the posterior wall of the vertebral body （DCPW） of thoracolumbar vertebrae was measured from C-arm images. The selected vertebrae were divided into two groups according to DCPW, with the fracture levels, fracture grades and leakage rates of the two groups compared. A relative operating characteristic （ROC） curve was applied to determine whether the DCPW difference can be used to estimate the degree of cement leakage. The data were processed by statistical software SPSS version 21.0 using independent sample t-test and Chi-square tests. Results： The maximum DBCV was 6.40 mm and the average DBCV was 3.74 ± 0.95 mm. DBCV appeared to be longer in males than in females, but the difference was not statistically significant. The average DCPW of type-B leakage vertebrae （2.59 ±1.20 ram） was shorter than that of other vertebrae （7.83 ±2.38 mm, P 〈 0.001）. The leakage rate of group DCPW ≤6.40 mm was lower than that of group DCPW 〉6.40 mm for type-C and type-S, but much higher for type-B. ROC curve revealed that DCPW only has a predictive value for type-B leakage （area under the curve： 0.98, 95% confidence interval： 0.95-0.99, P 〈 0.001）, and when the cut-ott＇value was 4.05 mm, the di

关键词： C-arm Image Complications Kyphoplasty Vertebrae Vertebroplasty

A CONNECTION ADMISSION CONTROL SCHEME BASED ON GAME THEORETICAL MODEL IN ATM NETWORKS

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Journal of Electronics(China) 1999年第1期16卷 7-15页

作者： chen Huimin Wang pu li Yanda (Department of Automation, Tsinghua University, Beijing 100084) Department of Automation Tsinghua University Beijing

In this paper, the main schemes of connection admission control (CAC) in ATM networks are briefly discussed especially the principle of dynamic bandwidth allocation. Then the fair share of the bandwidth among different traffic sources is analyzed based on cooperative game model. A CAC scheme is proposed using the genetic algorithm (GA) to optimize the bandwidth-delay-product formed utilization function that ensures the fair share and accuracy of accepting/rejecting the incoming calls. Simulation results show that the proposed scheme ensures fairness of the shared bandwidth to different traffic sources.

关键词： Connection admission control Cooperative game model Genetic algorithm Dynamic bandwidth allocation ATM network

Cyano migration-mediated radical-polar crossover cyclopropanation

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Science China Chemistry 2025年第1期68卷 241-248页

作者： Ziqiang Wang Yasu chen Jie li chen Zhu Key Laboratory of Organic Synthesis of Jiangsu Province College of Chemistry Chemical Engineering and Materials ScienceSoochow University Frontiers Science Center for Transformative Molecules Zhangjiang Institute for Advanced Study and Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs Shanghai Jiao Tong University

We report a novel cyano migration-mediated radical-polar crossover process, whereby both the sulfonylcyanation of aliphatic alkenes and the formation of cyclopropanes are concurrently achieved. This transformation yields a diverse array of multisubstituted cyclopropanes under mild photocatalytic conditions. Mechanistic studies elucidate that the reaction proceeds via intramolecular nucleophilic substitution, leading to the formation of the cyclopropane derivatives.

关键词： cyclopropanation cyano migration radical-polar crossover radical reactions

Analysis of Pathological data of renal biopsy at one single center in China from 1987 to 2012

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Chinese Medical Journal 2014年第9期127卷 1715-1720页

作者： Zhang Xueguang liu Shuwen Tang li Wu Jie chen pu Yin Zhong li Minxia Xie Yuansheng Cai Guangyan Wei Ribao Qiu Qiang Wang Yuanda Shi Suozhu chen Xiangmei Department of Nephrology State Key Laboratory of Kidney Diseases (2011DAV00088) National Clinical Medical Research Center for Kidney Disease (2013BAI09B05) Chinese People's Liberation Army General Hospital Beijing 100853 China

Background In China,the prevalence of chronic kidney disease has increased *** studies shows that the spectrum of kidney disease had changed in recent *** retrospectively analyzed the pathological types of renal biopsy and its spectrum change at the General Hospital of the Chinese People＇s liberation Army from December 1987 to December 2012,in order to offer new supporting evidences for further specifying the distribution of renal pathological types in *** According to the ＂Revised Protocol for the Histological Typing of Glomerulopathy＂（WHO,1995）,pathological diagnosis of renal biopsy was classified,detection rate of each pathological type was summarized （i.e.,percentage of total renal biopsy cases）,study period was divided at an interval of 5 years,and age-stratified distribution change of main pathological types was *** The proportion of pathological types in 11 618 cases of renal biopsy was as follows：primary glomerulonephritis （PGN,70.7％）,secondary glomerulonephritis （SGN,20.7％）,tubular-interstitial nephropathy （4.0％）,hereditary/rare nephropathy （0.3％）,end-stage renal disease （0.9％）,and unclassified renal disease （3.3％）.Among PGN,there was IgA nephropathy （IgAN,37.0％）,membranous nephropathy （MN,11.8％）,mesangial proliferative glomerulonephritis （MsPGN,8.9％）,minimal change disease （MCD,6.6％）,and focal segmental glomerulosclerosis （3.9％）.Among SGN there was lupus nephritis （LN,5.5％）,Henoch-Sch（o）nlein purpura glomerulonephritis （5.3％）,hepatitis B virus-associated nephritis （HBVAN,3.03％）,diabetic nephropathy （2.2％）,and hypertension/malignant hypertension-associated renal damage （1.9％）.Pathological data were analyzed from 1987-1992 to 2008-2012 （after age adjustment）.Detection rate of IgAN tended to rise （P ＜0.001）.Detection rates of MN and MCD rose significantly （P ＜0.001）,but detection rate of MsPGN dropped significantly （P ＜0.001）.Among SGN,detection rate of HBVAN tended to drop （P ＜0.001）.Conclusion In China,PGN was the

关键词： renal biopsy kidney disease detection rate

Cell polarization in ischemic stroke: molecular mechanisms and advances

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Neural Regeneration Research 2025年第3期20卷 632-645页

作者： Yuanwei li Xiaoxiao Xu Xuan Wu Jiarui li Shiling chen Danyang chen Gaigai li Zhouping Tang Department of Neurology Tongji HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhanHubei ProvinceChina

Ischemic stroke is a cerebrovascular disease associated with high mortality and disability rates. Since the inflammation and immune response play a central role in driving ischemic damage, it becomes essential to modulate excessive inflammatory reactions to promote cell survival and facilitate tissue repair around the injury site. Various cell types are involved in the inflammatory response, including microglia, astrocytes, and neutrophils, each exhibiting distinct phenotypic profiles upon stimulation. They display either proinflammatory or anti-inflammatory states, a phenomenon known as ‘cell polarization.’ There are two cell polarization therapy strategies. The first involves inducing cells into a neuroprotective phenotype in vitro, then reintroducing them autologously. The second approach utilizes small molecular substances to directly affect cells in vivo. In this review, we elucidate the polarization dynamics of the three reactive cell populations(microglia, astrocytes, and neutrophils) in the context of ischemic stroke, and provide a comprehensive summary of the molecular mechanisms involved in their phenotypic switching. By unraveling the complexity of cell polarization, we hope to offer insights for future research on neuroinflammation and novel therapeutic strategies for ischemic stroke.

关键词： astrocyte polarization immune regulation inflammation ischemic injury microglia polarization neutrophil polarization signaling pathways stroke

Targeting cholesterol trafficking to mitigate axonal degeneration in hereditary spastic paraplegia

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Neural Regeneration Research 2025年第5期20卷 1397-1398页

作者： Zhenyu chen Xue-Jun li Department of Biomedical Sciences University of Illinois College of Medicine RockfordRockfordILUSA Department of Bioengineering University of Illinois at ChicagoChicagoILUSA

Axonal degeneration underlies many debilitating diseases including hereditary spastic paraplegia(HSP),a genetically and clinically diverse group of disorders characterized by spasticity and weakness of the lower *** is one significant cause of chronic neurodisability due to the lack of effective treatments and a wide range of onset ages from early childhood to 70 years.

关键词： degeneration diseases hereditary