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Stepping up after spinal cord injury:negotiating an obstacle during walking

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Neural Regeneration Research 2025年第7期20卷 1919-1929页

作者： Alain Frigon Charly G.Lecomte Department of Pharmacology-Physiology Faculty of Medicine and Health SciencesUniversitéde SherbrookeCentre de recherche du Centre Hospitalier Universitaire de SherbrookeSherbrookeQCCanada

Every day walking consists of frequent voluntary modifications in the gait pattern to negotiate *** spinal cord injury,stepping over an obstacle becomes *** over an obstacle requires sensorimotor transformations in several structures of the brain,including the parietal cortex,premotor cortex,and motor *** information and planning are transformed into motor commands,which are sent from the motor cortex to spinal neuronal circuits to alter limb trajectory,coordinate the limbs,and maintain *** spinal cord injury,bidirectional communication between the brain and spinal cord is disrupted and animals,including humans,fail to voluntarily modify limb trajectory to step over an ***,in this review,we discuss the neuromechanical control of stepping over an obstacle,why it fails after spinal cord injury,and how it recovers to a certain extent.

关键词： biomechanics locomotion neurophysiology obstacle negotiation spinal cord injury

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Bimetallic Single‑Atom Catalysts for Water Splitting

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Nano-Micro Letters 2025年第1期17卷 1-45页

作者： Megha A.Deshmukh Aristides Bakandritsos Radek Zbořil Nanotechnology centre Centre for Energy and Environmental TechnologiesVŠB–Technical University of Ostrava17.listopadu 2172/1570800 Ostrava‑PorubaCzech Republic Regional centre of Advanced Technologies and Materials Czech Advanced Technology and Research Institute(CATRIN)Palacky University OlomoucŠlechtitelů241/2778371 Olomouc–HoliceCzech Republic

Green hydrogen from water splitting has emerged as a critical energy vector with the potential to spearhead the global transition to a fossil fuel-independent *** field of catalysis has been revolutionized by single-atom catalysts(SACs),which exhibit unique and intricate interactions between atomically dispersed metal atoms and their ***,bimetallic SACs(bimSACs)have garnered significant attention for leveraging the synergistic functions of two metal ions coordinated on appropriately designed *** offer an avenue for rich metal–metal and metal–support cooperativity,potentially addressing current limitations of SACs in effectively furnishing transformations which involve synchronous proton–electron exchanges,substrate activation with reversible redox cycles,simultaneous multi-electron transfer,regulation of spin states,tuning of electronic properties,and cyclic transition states with low activation *** review aims to encapsulate the growing advancements in bimSACs,with an emphasis on their pivotal role in hydrogen generation via water *** subsequently delve into advanced experimental methodologies for the elaborate characterization of SACs,elucidate their electronic properties,and discuss their local coordination ***,we present comprehensive discussion on the deployment of bimSACs in both hydrogen evolution reaction and oxygen evolution reaction,the two half-reactions of the water electrolysis process.

关键词： Single-atom catalysts Single-atom dimers Hydrogen evolution Oxygen evolution Water splitting

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Tetracycline-inducible Expression Systems: New Strategies and Practices in the Transgenic Mouse Modeling

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Acta Biochimica et Biophysica Sinica 2007年第4期39卷 235-246页

作者： Yan SUN~(1,2) Xigu CHEN~1* Dong XIAO~2* 1 Center of experimental animals,Sun Yar.Sen University,Guangzhou 510080,China 2 Institute of Comparative Medicine and Center of experimental animals,Southern Medical University Guangzhou 510515,China Center of experimental animals Sun Yat-Sen UniversityGuangzhou 510080 China Institute of Comparative Medicine and Center of experimental animals Southern Medical UniversityGuangzhou 510515 China

To accurately analyze the function of transgene(s)of interest in transgenic mice,and togenerate credible transgenic animal models for multifarious human diseases to precisely mimic human dis-ease states,it is critical to tightly regulate gene expression in the animals in a conditional *** abilityto turn gene expression on or off in the restricted cells or tissues at specific time permits unprecedentedflexibility in dissecting gene functions in health and *** studies in conditional transgene ex-pression have brought about the development of a wide variety of controlled gene expression systems,whichmeet this *** them,the tetracycline-controlled expression systems(***-off system andTet-on system)have been used extensively in vitro and in *** recent years,some strategies derived fromtetracycline-inducible system alone,as well as the combined use of Tet-based systems and Cre/lox P switch-ing gene expression system,have been newly developed to allow more flexibility for exploring gene functionsin health and disease,and produce credible transgenic animal models for various human *** thisreview these newly developed strategies are discussed.

关键词： tetracycline-inducible expression system Cre/lox P system transgenic mouse modeling leaky expression stringent control lineage-specific gene expression lineage-specific RNAi

Tetracycline-controlled transcriptional regulation systems: countermeasures to eliminate basal transgene leaks in Tet-based systems

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Progress in Natural Science:Materials International 2007年第1期17卷 11-19页

作者： XIAO Dong, SUN Yan, GU Weiwang and CHEN Xigu ( Center of experimental animals and Institute of Comparative Medicine, Southern Medical University, Guangzhou 510515, China Center of experimental animals, Sun Yat-sen University, Guangzhou 510080, China) Center of experimental animals Institute of Comparative Medicine Southern Medical University Guangzhou 510515 China Center of experimental animals Sun Yat-sen University Guangzhou 510080 China

To analyze the function of any given transgene(s) accurately in transgenic mice, and to produce credible transgenic animal models of various human diseases (precisely and realistically mimicking disease states), it is critical to be able to control gene expression in the animals conditionally. The ability to switch gene expression "on" or "off" in the restricted cells or tissue(s) at specific time(s) allows unprecedented flexibility for exploring gene function(s) in both the health and the disease. Pioneering work on inducible transgene expression has led to the development of a wide variety of controlled gene expression systems that meet this criterion. Among them, the tetracycline-inducible systems (e.g. Tet-off and Tet-on) have been widely, frequently and successfully employed in vitro and in vivo. These systems, however, are not always tight but leaky; sometimes the leakage is significant. In some circumstances, the resulting leak is acceptable, but in others, it is more problematic. Though these systems face this disadvantage, i. e. basal transgene leakage in vitro and in vivo, several approaches, including using improved versions (e.g. rtTA2S-M2 and rtTA2S-S2) of rtTA, tetracycline-controlled transcriptional silencer (tTS), an "ideal" minimal promoter in responsive components or combinations thereof, have been developed to avoid this limitation effectively. In this review we discuss the countermeasures available to eliminate basal transgene leakage from Tet-based systems.

关键词： tetracycline inducible system transgenic mice leaky expression transcriptional silencer.

A Wind Tunnel experimental Study on the Wake Characteristics of a Horizontal Axis Wind Turbine

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Journal of Thermal Science 2025年第1期34卷 145-158页

作者： GUO Xingduo LI Yinran LI Rennian MA Yulong WEI Kui College of Energy and Power Engineering Lanzhou University of Technology Key Laboratory of Fluid Machinery and Systems Gansu Provincial Technology centre for Wind Turbines

The characteristics of wind turbine wakes are influenced by multiple factors,including the atmospheric boundary layer(ABL) wind and wind turbine operating conditions(e.g.,tip speed ratio and yaw angle).In this study,two types of ABL winds with different velocity gradients and turbulence intensities are generated in a wind tunnel through configurations of spires,baffles,and various numbers of roughness elements.A wind turbine with a rotor diameter of 0.8 m and a hub height of 0.6 m is tested under varying tip speed ratios,yaw angles,and ABL wind *** results indicate that the streamwise velocity deficit in the near-wake region becomes more pronounced with an increase in the tip speed ratio,while the far-wake velocity deficit remains largely unaffected by changes in the tip speed *** the yaw angle increases,the wake deflection becomes more prominent and the wake narrows;the offset of the wake center at various downstream positions grows linearly,reaching a maximum value of approximately half the rotor ***,the turbulence level and influence range in the wake region are reduced when the turbine is *** ABL wind conditions,high turbulence intensity in the incoming flow accelerates wake recovery,and the Reynolds stress at different lateral positions tends to become consistent with increasing longitudinal ***,turbulence has a significant impact on the meandering characteristics of the wind turbine wake,with greater fluctuations in the wake center observed under higher turbulence ***,this study provides insights that could inform the optimal operation of wind farms.

关键词： horizontal axis wind turbine turbulence wind tunnel experiment wind turbine wake

experimental Study for Effect of Multi-Site Spark Ignition on Dedicated Hybrid Engine Performance under High Dilution Condition

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Journal of Thermal Science 2025年第1期34卷 254-267页

作者： YAN Bowen WATERS Benjamin HAINES Andrew MCGHEE Mike HU Tiegang DENG Wei PU Yongxian MA Tianyu Powertrain Engineering R&D Center Chongqing Changan Automobile Co.Ltd. Changan UK R&D centre Limited

In this study,a triple spark ignition scheme was first designed on a three-cylinder 1.5-L dedicated hybrid engine（DHE）.On this basis,the effect of different ignition modes on engine combustion and emission characteristics was studied,especially under high dilution *** results tested at 2000 r/min and 0.8 MPa BMEP（brake mean effective pressure） show that with highly increased in-cylinder flow intensity,using only passive prechamber（PPC） has a lower lean limit than that with single central spark plug（CSP）,thereby leading to slightly higher minimum fuel consumption and nitrogen oxides（NOx） *** side spark plugs（SSP）based on PPC can result in improved capability of lean limit extension and engine performance than ***,the improvement level is lower than that with triple spark plugs（TSP）.As the excess air ratio λincreases,the advantage of PPC and PPC with SSP in improving the combustion phasing compared with CSP gradually ***,the increasing tendency of their ignition delay and combustion duration is more *** added SSP based on PPC can effectively shorten the ignition delay of leaner mixture,but the combustion duration can be only slightly *** a result,under extremely lean condition,the advantage of PPC and PPC with SSP in terms of combustion characteristics over CSP becomes much *** contrast,the TSP ignition can achieve much shorter ignition delay and combustion duration simultaneously under this *** to the highest available dilution level,the TSP ignition achieves the lowest raw ***,it can also reduce the raw carbon monoxide（CO） and hydrocarbons（HC） emissions compared to CSP due to a more thorough combustion of the end gas *** on the excellent performance of TSP,the highest engine brake thermal efficiency（BTE） was further *** results show that with normal RON 92 fuel,the engine finally achieved 43.69% and 45.02% BTE under stochiometric mode with exhaust

关键词： dedicated hybrid engine high dilution condition NOx emissions passive prechamber thermal efficiency triple spark plug scheme

Traffic safety helmet wear detection based on improved YOLOv5 network

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Optoelectronics Letters 2025年第1期21卷 35-42页

作者： GUI Dongdong SUN Bo College of Software Southeast University Quanzhou Equipment Research centre Haixi Institute Chinese Academy of Sciences

Aiming at the problem that the current traffic safety helmet detection model can't balance the accuracy of detection with the size of the model and the poor generalization of the model, a method based on improving you only look once version 5(YOLOv5) is proposed. By incorporating the lightweight Ghost Net module into the YOLOv5 backbone network, we effectively reduce the model size. The addition of the receptive fields block(RFB) module enhances feature extraction and improves the feature acquisition capability of the lightweight model. Subsequently, the high-performance lightweight convolution, GSConv, is integrated into the neck structure for further model size compression. Moreover, the baseline model's loss function is substituted with efficient insertion over union(EIoU), accelerating network convergence and enhancing detection precision. experimental results corroborate the effectiveness of this improved algorithm in real-world traffic scenarios.

关键词： Traffic control

Generation of human/rat xenograft animal model for the study of human donor stem cell behaviors in vivo

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World Journal of Gastroenterology 2007年第19期13卷 2707-2716页

作者： Yan Sun Dong Xiao Xing-Hua Pan Ruo-Shuang Zhang Guang-Hui Cui Xi-Gu Chen Center of experimental animals Sun Yat-sen University Guangzhou 510080 Guangdong Province China Institute of Comparative Medicine and Center of experimental animals Southern Medical University Guangzhou 510515 Guangdong Province China Clinic experimental Department Kunming General Hospital Chengdu Military District of PLA Kunming 650032 Yunnan Province China

AIM： TO accurately and realistically elucidate human stem cell behaviors in vivo and the fundamental mechanisms controlling human stem cell fates in vivo, which is urgently required in regenerative medicine and treatments for some human diseases, a surrogate human-rat chimera model was developed. METHODS： Human-rat chimeras were achieved by in utero transplanting low-density mononuclear cells from human umbilical cord blood into the fetal rats at 9-11 d of gestation, and subsequently, a variety of methods, including flow cytometry, PCR as well as immunohistochemical assay, were used to test the human donor contribution in the recipients. RESULTS： Of 29 live-born recipients, 19 had the presence of human CD45^＋ cells in peripheral blood （PB） detected by flow cytometry, while PCR analysis on genomic DNA from 11 different adult tissues showed that 14 selected from flow cytometry-positive 19 animals possessed of donor-derived human cell engraftment in multiple tissues （i.e. liver, spleen, thymus, heart, kidney, blood, lung, muscle, gut and skin） examined at the time of tissue collection, as confirmed by detecting human 132- microglobulin expression using immunohistochemistry. Tn this xenogeneic system, the engrafted donor-derived human cells persisted in multiple tissues for at least 6 mo after birth. Moreover, transplanted human donor cells underwent site-specific differentiation into CK18-positive human cells in chimeric liver and CEHS-positive human cells in chimeric spleen and thymus of recipients. CONCLUSION： Taken together, these findings suggest that we successfully developed human-rat chimeras, in which xenogeneic human cells exist up to 6 mo later. This humanized small animal model, which offers an in vivo environment more closely resembling to the situations in human, provides an invaluable and effective approach for in vivo investigating human stem cell behaviors, and further in vivo examining fundamental mechanisms controlling human stem cell fates in the fut

关键词： Human umbilical cord blood-derived cells In utero xenogeneic transplantation Human-rat chimeras Embryonic microenvironment In vivo model

Rescue of the albino phenotype by introducing a functional tyrosinase minigene into Kunming albino mice

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World Journal of Gastroenterology 2007年第2期13卷 244-249页

作者： Dong Xiao Ying Yue Xin-Yan Deng Bing Huang Zhong-Min Guo Yun Ma Yi-Li Lin Xun Hong Huan Tang Kang Xu Xi-Gu Chen Center of experimental animals Sun Yat-sen University Guangzhou 510080 Guangdong Province China Institute of Comparative Medicine and Center of experimental animals Southern Medical University Guangzhou 510515 Guangdong Province China Department of Animal Science College of Basic Medicine the Third Military Medical University Chongqing 400038 China

AIM： To use the tyrosinase minigene as a visual marker to perform microinjection training and improve the techniques related with transgene to greatly elevate the effidency of gene transfer. METHODS： A mouse tyrosinase minigene, i.e., TyBS, in which the 2.25-kb authentic genomic 5＇ non-coding flanking sequence of mouse tyrosinase was fused to a mouse tyrosinase cDNA, was introduced into the fertilized eggs of outbred Kunming albino mice. RESULTS： Of the 11 animals that developed from the injected eggs, two mice （P1 and #8） exhibited pigmented hair （P1） and eyes （P1 and #8）, as confirmed by PCR analysis for the tyrosinase minigene integrated into the genome. When founder P1 was bred to Kunming male mouse, six progeny out of 11 offspring inherited the transgene and the pigmented-eye phenotype. CONCLUSION： Taken together, these results suggest that this minigene encodes the active tyrosinase protein and that its 5＇ flanking region contains the sequences regulating the expression of mouse tyrosinase gene as expected. We have rescued the albino phenotype by introduction and expression of a functional tyrosinase minigene in the Kunming albino mouse and the transgene can be passed to subsequent generation. These findings also indicate that TyBS can be a useful visual marker gene in the co-transgenic experiments.

关键词： minigene Transgenic mice Melanization Phenotypic rescue