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Path Planning for Robotic Arms Based on an Improved RRT Algorithm
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作者 wei liu Zhennan Huang +1 位作者 Yingpeng Qu Long Chen 《Open Journal of Applied Sciences》 2024年第5期1214-1236,共23页
The burgeoning robotics industry has catalyzed significant strides in the development and deployment of industrial and service robotic arms, positioning path planning as a pivotal facet for augmenting their operationa... The burgeoning robotics industry has catalyzed significant strides in the development and deployment of industrial and service robotic arms, positioning path planning as a pivotal facet for augmenting their operational safety and efficiency. Existing path planning algorithms, while capable of delineating feasible trajectories, often fall short of achieving optimality, particularly concerning path length, search duration, and success likelihood. This study introduces an enhanced Rapidly-Exploring Random Tree (RRT) algorithm, meticulously designed to rectify the issues of node redundancy and the compromised path quality endemic to conventional RRT approaches. Through the integration of an adaptive pruning mechanism and a dynamic elliptical search strategy within the Informed RRT* framework, our algorithm efficiently refines the search tree by discarding branches that surpass the cost of the optimal path, thereby refining the search space and significantly boosting efficiency. Extensive comparative analysis across both two-dimensional and three-dimensional simulation settings underscores the algorithm’s proficiency in markedly improving path precision and search velocity, signifying a breakthrough in the domain of robotic arm path planning. 展开更多
关键词 Robotic Arm Path Planning RRT Algorithm Adaptive Pruning Optimization
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Phase-Based Optical Flow Method with Optimized Parameter Settings for Enhancing Displacement Measurement Adaptability
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作者 Zhaoxin Peng Menglian liu +2 位作者 Zhiliang Wang wei liu Xian Wang 《Open Journal of Applied Sciences》 2024年第5期1165-1184,共20页
To enhance the applicability and measurement accuracy of phase-based optical flow method using complex steerable pyramids in structural displacement measurement engineering applications, an improved method of optimizi... To enhance the applicability and measurement accuracy of phase-based optical flow method using complex steerable pyramids in structural displacement measurement engineering applications, an improved method of optimizing parameter settings is proposed. The optimized parameters include the best measurement points of the Region of Interest (ROI) and the levels of pyramid filters. Additionally, to address the issue of updating reference frames in practical applications due to the difficulty in estimating the maximum effective measurement value, a mechanism for dynamically updating reference frames is introduced. Experimental results demonstrate that compared to representative image gradient-based displacement measurement methods, the proposed method exhibits higher measurement accuracy in engineering applications. This provides reliable data support for structural damage identification research based on vibration signals and is expected to broaden the engineering application prospects for structural health monitoring. 展开更多
关键词 Displacement Measurement Phase-Based Optical Flow Optimized Parameter Setting
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钙固化碱焙烧−水浸法从二次铝渣中分离氟和铝
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作者 董良民 焦芬 +3 位作者 刘维 黄雅琳 魏鑫 覃文庆 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2024年第6期2007-2019,共13页
设计一种钙固化碱焙烧−水浸出联合工艺处置二次铝渣,研究CaO用量、NaOH用量、焙烧温度和时间对铝溶出和氟固化行为的影响。在最佳实验条件(焙烧温度1000℃、Al与NaOH摩尔比1꞉0.6、F与CaO摩尔比1꞉2.5、焙烧时间2.0 h)下,氟和铝被分离,其... 设计一种钙固化碱焙烧−水浸出联合工艺处置二次铝渣,研究CaO用量、NaOH用量、焙烧温度和时间对铝溶出和氟固化行为的影响。在最佳实验条件(焙烧温度1000℃、Al与NaOH摩尔比1꞉0.6、F与CaO摩尔比1꞉2.5、焙烧时间2.0 h)下,氟和铝被分离,其中氟固化率为99.98%,铝溶出率为52.97%。水浸液经蒸发结晶,可得到符合中国工业标准的NaAlO_(2)产品;水浸渣可作为速凝水泥原料。总体而言,此研究为处置二次铝渣提供了一个有效、环保的解决方案。 展开更多
关键词 二次铝渣 钙固化碱焙烧 分离 偏铝酸钠 清洁生产
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超高速激光金属沉积增材制造K648高温合金的显微组织与性能
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作者 王开明 刘炜 +7 位作者 都东 常保华 刘冠 胡永乐 仝永刚 张明军 张健 鞠江 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2024年第7期2192-2203,共12页
采用一种新型的超高速激光金属沉积工艺以提高高铬高温合金的制造效率。分别使用透射电子显微镜、拉伸试验机、磨损试验机和电化学工作站对超高速激光金属沉积高铬K648高温合金的析出相生长行为、高温力学性能、耐磨性和耐腐蚀性进行研... 采用一种新型的超高速激光金属沉积工艺以提高高铬高温合金的制造效率。分别使用透射电子显微镜、拉伸试验机、磨损试验机和电化学工作站对超高速激光金属沉积高铬K648高温合金的析出相生长行为、高温力学性能、耐磨性和耐腐蚀性进行研究,并与传统激光金属沉积工艺进行比较。结果表明,超高速激光金属沉积K648合金的析出相尺寸明显小于传统激光金属沉积工艺制备的K648合金,700℃下的高温强度更高,且具有良好的耐磨性和耐腐蚀性。总之,超高速激光金属沉积制造的K648高铬高温合金具有良好的综合性能。 展开更多
关键词 增材制造 超高速激光金属沉积 K648高温合金 显微组织演变 性能
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完全暴露的碳基电极边缘-平面位点用于高效水氧化
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作者 郭静雅 刘炜 +9 位作者 商文喆 司端惠 朱超 胡金文 辛存存 程旭升 张松林 宋俗禅 王秀云 史彦涛 《Chinese Journal of Catalysis》 SCIE CAS CSCD 2024年第5期272-283,共12页
开发经济高效的析氧反应电催化剂对于推进可充电金属-空气电池和电解水技术的发展至关重要.一般来说,具有完整蜂窝结构的石墨碳基面是电化学惰性的,需要依赖缺陷或者掺杂结构诱导的电荷极化效应来提升催化活性.相比于基面,边缘位点具有... 开发经济高效的析氧反应电催化剂对于推进可充电金属-空气电池和电解水技术的发展至关重要.一般来说,具有完整蜂窝结构的石墨碳基面是电化学惰性的,需要依赖缺陷或者掺杂结构诱导的电荷极化效应来提升催化活性.相比于基面,边缘位点具有特殊的局域电子态,为提升石墨碳电极的本征催化活性开辟了新的思路,然而其结构精准构筑目前仍面临极大挑战.本文以“人字形”多壁碳纳米管(H-MWCNTs)作为研究切入点,利用高温熔盐介质主导的插层剥离和截断效应,实现“边缘-平面位点”结构可控构筑,为实现高效电解水析氧反应(OER)提供了重要的结构基础.通过熔盐辅助热解方法可控制备了具有完全暴露的内外边缘平面的目标催化剂H-MWCNTs-MS,并研究其OER催化性能.在碱性介质中10 mA cm^(-2)电流密度所需过电位仅为236 mV,是目前报道的较好的非金属电催化剂.同时,H-MWCNTs-MS在10,50和100 mA cm^(-2)电流密度下均表现出较好的电化学稳定性.利用原位衰减全反射-表面增强红外吸收光谱(ATR-SEIRAS)技术研究了“边缘-平面位点”在OER过程中的结构重构过程,与理论计算分析的高能“边缘态”结果一致,并确定酮氧官能化位点为真实催化活性中心.理论计算结果表明,氧官能团修饰结构能够显著促进电荷的再分配,增强层间耦合作用,降低关键含氧中间体*OOH的形成能垒,加速OER反应动力学.此外,H-MWCNTs-MS的开放式结构极大程度提高了“边缘-平面位点”的利用率,减小的纳米管壁厚促进了层间电荷迁移,也是增强OER活性的关键要素.综上,精准构筑“边缘-平面位点”为开发高效石墨碳电极开辟了新的思路,通过原位谱学技术揭示边缘位点催化结构重构,能够进一步丰富研究者对于电催化协同效应的科学认识. 展开更多
关键词 多壁碳纳米管 边缘-平面位点 析氧反应 熔融盐 电子耦合
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边缘场景下面向分布式交互应用的服务器分配
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作者 顾颖程 魏柳 +7 位作者 姜宁 程环宇 刘凯 宋玉 刘梅招 汤雷 陈彧 张胜 《计算机工程与科学》 CSCD 北大核心 2024年第10期1748-1756,共9页
移动边缘计算作为一种极具前瞻性的分布式计算范式,将云计算的计算能力下沉到网络边缘来高效地处理数据。近年来,分布式交互应用的需求激增,移动智能设备数量爆炸性增长,作为移动边缘计算的重要组成部分,边缘服务器可以使交互应用程序... 移动边缘计算作为一种极具前瞻性的分布式计算范式,将云计算的计算能力下沉到网络边缘来高效地处理数据。近年来,分布式交互应用的需求激增,移动智能设备数量爆炸性增长,作为移动边缘计算的重要组成部分,边缘服务器可以使交互应用程序在用户附近执行,从而解决通信和网络开销过大和数据无法即时处理的问题。一个关键的挑战是找到一个合适的边缘服务器分配策略以有效降低交互延迟和平衡服务器工作负载。基于此目标提出了边缘服务器分配算法ESADQN,将问题建模为马尔可夫决策过程,使用强化学习有效地选择边缘服务器部署位置,并将用户分配到相应服务器。与k-means算法相比,ESADQN算法在工作负载标准差相近的情况下,总交互时延平均减少了31%;与Top-K算法相比,ESADQN算法在总交互时延相近的情况下,工作负载标准差平均减少了49%。实验结果表明,ESADQN选择的服务器分配方案能有效降低交互时延和工作负载标准差。 展开更多
关键词 边缘计算 服务器分配 分布式交互应用 马尔可夫决策过程 强化学习
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Long-term prognosis and its associated predictive factors in patients with eosinophilic gastroenteritis 被引量:3
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作者 Kai-Wen Li Ge-Chong Ruan +8 位作者 Shuang liu Tian-Ming Xu Ye Ma wei-Xun Zhou wei liu Peng-Yu Zhao Zhi-Rong Du Ji Li Jing-Nan Li 《World Journal of Gastroenterology》 SCIE CAS 2024年第2期146-157,共12页
BACKGROUND Eosinophilic gastroenteritis(EGE)is a chronic recurrent disease with abnormal eosinophilic infiltration in the gastrointestinal tract.Glucocorticoids remain the most common treatment method.However,disease ... BACKGROUND Eosinophilic gastroenteritis(EGE)is a chronic recurrent disease with abnormal eosinophilic infiltration in the gastrointestinal tract.Glucocorticoids remain the most common treatment method.However,disease relapse and glucocorticoid dependence remain notable problems.To date,few studies have illuminated the prognosis of EGE and risk factors for disease relapse.AIM To describe the clinical characteristics of EGE and possible predictive factors for disease relapse based on long-term follow-up.METHODS This was a retrospective cohort study of 55 patients diagnosed with EGE admitted to one medical center between 2013 and 2022.Clinical records were collected and analyzed.Kaplan-Meier curves and log-rank tests were conducted to reveal the risk factors for long-term relapse-free survival(RFS).RESULTS EGE showed a median onset age of 38 years and a slight female predominance(56.4%).The main clinical symptoms were abdominal pain(89.1%),diarrhea(61.8%),nausea(52.7%),distension(49.1%)and vomiting(47.3%).Forty-three(78.2%)patients received glucocorticoid treatment,and compared with patients without glucocorticoid treatments,they were more likely to have elevated serum immunoglobin E(IgE)(86.8%vs 50.0%,P=0.022)and descending duodenal involvement(62.8%vs 27.3%,P=0.046)at diagnosis.With a median follow-up of 67 mo,all patients survived,and 56.4%had at least one relapse.Six variables at baseline might have been associated with the overall RFS rate,including age at diagnosis<40 years[hazard ratio(HR)2.0408,95%confidence interval(CI):1.0082–4.1312,P=0.044],body mass index(BMI)>24 kg/m^(2)(HR 0.3922,95%CI:0.1916-0.8027,P=0.014),disease duration from symptom onset to diagnosis>3.5 mo(HR 2.4725,95%CI:1.220-5.0110,P=0.011),vomiting(HR 3.1259,95%CI:1.5246-6.4093,P=0.001),total serum IgE>300 KU/L at diagnosis(HR 0.2773,95%CI:0.1204-0.6384,P=0.022)and glucocorticoid treatment(HR 6.1434,95%CI:2.8446-13.2676,P=0.003).CONCLUSION In patients with EGE,younger onset age,longer disease course,vomiting and glucocorticoid treatment were risk factors for disease relapse,whereas higher BMI and total IgE level at baseline were protective. 展开更多
关键词 Eosinophilic gastroenteritis PROGNOSIS RELAPSE GLUCOCORTICOID Glucocorticoid dependence
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数字化赋能无机与分析化学实验的教学资源建设及应用
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作者 方思敏 吴红 +3 位作者 刘卫 魏伟 冯红艳 李婉 《大学化学》 CAS 2024年第10期156-163,共8页
数字教育是推进教育高质量发展的重要途径,而数字资源的建设与应用显得尤为重要。在数字化赋能的时代背景下,我校无机与分析化学实验课程从制作教学视频资源库、开发双语版虚拟仿真实验、引进优质共享资源三方面建设教学资源,并应用于... 数字教育是推进教育高质量发展的重要途径,而数字资源的建设与应用显得尤为重要。在数字化赋能的时代背景下,我校无机与分析化学实验课程从制作教学视频资源库、开发双语版虚拟仿真实验、引进优质共享资源三方面建设教学资源,并应用于教学实践中,从而丰富数字化教学资源,推动网络教学平台的完善与混合式教学模式的改革,最终增强实验教学灵活性,促进教学形式多样性,提高课堂教学有效性。 展开更多
关键词 无机与分析化学实验课程 数字教育 教学资源的建设与应用
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Effect of slope angle on fractured rock masses under combined influence of variable rainfall infiltration and excavation unloading 被引量:1
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作者 Xiaoshuang Li Qihang Li +3 位作者 Yunmin Wang wei liu Di Hou Chun Zhu 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第10期4154-4176,共23页
Intense precipitation infiltration and intricate excavation processes are crucial factors that impact the stability and security of towering and steep rock slopes within mining sites.The primary aim of this research w... Intense precipitation infiltration and intricate excavation processes are crucial factors that impact the stability and security of towering and steep rock slopes within mining sites.The primary aim of this research was to investigate the progression of cumulative failure within a cracked rock formation,considering the combined effects of precipitation and excavation activities.The study was conducted in the Huangniuqian eastern mining area of the Dexing Copper Mine in Jiangxi Province,China.An engineering geological investigation was conducted,a physical model experiment was performed,numerical calculations and theoretical analysis were conducted using the matrix discrete element method(Mat-DEM),and the deformation characteristics and the effect of the slope angle of a fractured rock mass under different scenarios were examined.The failure and instability mechanisms of the fractured rock mass under three slope angle models were analyzed.The experimental results indicate that as the slope angle increases,the combined effect of rainfall infiltration and excavation unloading is reduced.A novel approach to simulating unsaturated seepage in a rock mass,based on the van Genuchten model(VGM),has been developed.Compared to the vertical displacement observed in a similar physical experiment,the average relative errors associated with the slope angles of 45,50,and 55were 2.094%,1.916%,and 2.328%,respectively.Accordingly,the combined effect of rainfall and excavation was determined using the proposed method.Moreover,the accuracy of the numerical simulation was validated.The findings contribute to the seepage field in a meaningful way,offering insight that can inform and enhance existing methods and theories for research on the underlying mechanism of ultra-high and steep rock slope instability,which can inform the development of more effective risk management strategies. 展开更多
关键词 Open-pit to underground excavation Rainfall infiltration Similarity simulation Numerical simulation Image recognition Slope angle
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Altered synaptic currents,mitophagy,mitochondrial dynamics in Alzheimer's disease models and therapeutic potential of Dengzhan Shengmai capsules intervention 被引量:1
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作者 Binbin Zhao Dongfeng wei +12 位作者 Qinghua Long Qingjie Chen Fushun Wang Linlin Chen Zefei Li Tong Li Tao Ma wei liu Linshuang Wang Caishui Yang Xiaxia Zhang Ping Wang Zhanjun Zhang 《Journal of Pharmaceutical Analysis》 SCIE CAS CSCD 2024年第3期348-370,共23页
Emerging research suggests a potential association of progression of Alzheimer's disease(AD)with alterations in synaptic currents and mitochondrial dynamics.However,the specific associations between these patholog... Emerging research suggests a potential association of progression of Alzheimer's disease(AD)with alterations in synaptic currents and mitochondrial dynamics.However,the specific associations between these pathological changes remain unclear.In this study,we utilized Aβ42-induced AD rats and primary neural cells as in vivo and in vitro models.The investigations included behavioural tests,brain magnetic resonance imaging(MRI),liquid chromatography-tandem mass spectrometry(UPLC-MS/MS)analysis,Nissl staining,thioflavin-S staining,enzyme-linked immunosorbent assay,Golgi-Cox staining,transmission electron microscopy(TEM),immunofluorescence staining,proteomics,adenosine triphosphate(ATP)detection,mitochondrial membrane potential(MMP)and reactive oxygen species(ROS)assessment,mitochondrial morphology analysis,electrophysiological studies,Western blotting,and molecular docking.The results revealed changes in synaptic currents,mitophagy,and mitochondrial dynamics in the AD models.Remarkably,intervention with Dengzhan Shengmai(DZSM)capsules emerged as a pivotal element in this investigation.Aβ42-induced synaptic dysfunction was significantly mitigated by DZSM intervention,which notably amplified the frequency and amplitude of synaptic transmission.The cognitive impairment observed in AD rats was ameliorated and accompanied by robust protection against structural damage in key brain regions,including the hippocampal CA3,primary cingular cortex,prelimbic system,and dysgranular insular cortex.DZSM intervention led to increased IDE levels,augmented long-term potential(LTP)amplitude,and enhanced dendritic spine density and length.Moreover,DZSM intervention led to favourable changes in mitochondrial parameters,including ROS expression,MMP and ATP contents,and mitochondrial morphology.In conclusion,our findings delved into the realm of altered synaptic currents,mitophagy,and mitochondrial dynamics in AD,concurrently highlighting the therapeutic potential of DZSM intervention. 展开更多
关键词 Alzheimer's disease Synaptic currents MITOPHAGY Mitochondrial fusion and fission Dengzhan Shengmai capsules
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Exploring non-curative endoscopic submucosal dissection:Current treatment optimization and future indication expansion 被引量:1
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作者 Yi-Nong Zhu Xiang-Lei Yuan +4 位作者 wei liu Yu-Hang Zhang Yi Mou Bing Hu Lian-Song Ye 《World Journal of Gastroenterology》 SCIE CAS 2024年第9期1257-1260,共4页
The increasing popularity of endoscopic submucosal dissection(ESD)as a treatment for early gastric cancer has highlighted the importance of quality assessment in achieving curative resections.This article emphasizes t... The increasing popularity of endoscopic submucosal dissection(ESD)as a treatment for early gastric cancer has highlighted the importance of quality assessment in achieving curative resections.This article emphasizes the significance of evaluating ESD quality,not only for curative cases but also for non-curative ones.Postoperative assessment relies on the endoscopic curability(eCura)classification,but management strategies for eCuraC-1 tumour with a positive horizontal margin are unclear.Current research primarily focuses on comparing additional surgical procedures in high-risk patients,while studies specifically targeting eCuraC-1 patients are limited.Exploring management strategies and follow-up outcomes for such cases could provide valuable insights.Furthermore,the application of molecular imaging using near-infrared fluorescent tracers holds promise for precise tumour diagnosis and navigation,potentially impacting the management of early-stage gastric cancer patients.Advancing research in these areas is essential for improving the overall efficacy of endoscopic techniques and refining treatment indications. 展开更多
关键词 Early gastric cancer Endoscopic submucosal dissection Quality control Noncurative endoscopic submucosal dissection Near-infrared fluorescent tracer
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Timosaponin AⅢ induces drug-metabolizing enzymes by activating constitutive androstane receptor (CAR) via dephosphorylation of the EGFR signaling pathway 被引量:1
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作者 Muhammad Zubair Hafiz Jie Pan +4 位作者 Zhiwei Gao Ying Huo Haobin Wang wei liu Jian Yang 《Journal of Biomedical Research》 CAS CSCD 2024年第4期382-396,共15页
The current study aimed to assess the effect of timosaponin AⅢ(T-AⅢ)on drug-metabolizing enzymes during anticancer therapy.The in vivo experiments were conducted on nude and ICR mice.Following a 24-day administratio... The current study aimed to assess the effect of timosaponin AⅢ(T-AⅢ)on drug-metabolizing enzymes during anticancer therapy.The in vivo experiments were conducted on nude and ICR mice.Following a 24-day administration of T-AⅢ,the nude mice exhibited an induction of CYP2B10,MDR1,and CYP3A11 expression in the liver tissues.In the ICR mice,the expression levels of CYP2B10 and MDR1 increased after a three-day T-AⅢ administration.The in vitro assessments with HepG2 cells revealed that T-AⅢ induced the expression of CYP2B6,MDR1,and CYP3A4,along with constitutive androstane receptor(CAR)activation.Treatment with CAR siRNA reversed the T-AⅢ-induced increases in CYP2B6 and CYP3A4 expression.Furthermore,other CAR target genes also showed a significant increase in the expression.The up-regulation of murine CAR was observed in the liver tissues of both nude and ICR mice.Subsequent findings demonstrated that T-AⅢ activated CAR by inhibiting ERK1/2 phosphorylation,with this effect being partially reversed by the ERK activator t-BHQ.Inhibition of the ERK1/2 signaling pathway was also observed in vivo.Additionally,T-AⅢ inhibited the phosphorylation of EGFR at Tyr1173 and Tyr845,and suppressed EGF-induced phosphorylation of EGFR,ERK,and CAR.In the nude mice,T-AⅢ also inhibited EGFR phosphorylation.These results collectively indicate that T-AⅢ is a novel CAR activator through inhibition of the EGFR pathway. 展开更多
关键词 timosaponin AⅢ CAR metabolism enzyme ERK1/2 signaling pathway EGFR signaling pathway
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Scinderin promotes glioma cell migration and invasion via remodeling actin cytoskeleton 被引量:1
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作者 Xin Lin Zhao Zhao +1 位作者 Shu-Peng Sun wei liu 《World Journal of Clinical Oncology》 2024年第1期32-44,共13页
BACKGROUND Glioma is one of the most common intracranial tumors,characterized by invasive growth and poor prognosis.Actin cytoskeletal rearrangement is an essential event of tumor cell migration.The actin dynamics-rel... BACKGROUND Glioma is one of the most common intracranial tumors,characterized by invasive growth and poor prognosis.Actin cytoskeletal rearrangement is an essential event of tumor cell migration.The actin dynamics-related protein scinderin(SCIN)has been reported to be closely related to tumor cell migration and invasion in several cancers.AIM To investigate the role and mechanism of SCIN in glioma.METHODS The expression and clinical significance of SCIN in glioma were analyzed based on public databases.SCIN expression was examined using real-time quantitative polymerase chain reaction and Western blotting.Gene silencing was performed using short hairpin RNA transfection.Cell viability,migration,and invasion were assessed using cell counting kit 8 assay,wound healing,and Matrigel invasion assays,respectively.F-actin cytoskeleton organization was assessed using F-actin staining.RESULTS SCIN expression was significantly elevated in glioma,and high levels of SCIN were associated with advanced tumor grade and wild-type isocitrate dehydrogenase.Furthermore,SCIN-deficient cells exhibited decreased proliferation,migration,and invasion in U87 and U251 cells.Moreover,knockdown of SCIN inhibited the RhoA/focal adhesion kinase(FAK)signaling to promote F-actin depolymerization in U87 and U251 cells.CONCLUSION SCIN modulates the actin cytoskeleton via activating RhoA/FAK signaling,thereby promoting the migration and invasion of glioma cells.This study identified the cancer-promoting effect of SCIN and provided a potential therapeutic target for the treatment of glioma. 展开更多
关键词 GLIOMA Scinderin Actin cytoskeleton RhoA/FAK signaling DEPOLYMERIZATION
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Unraveling the hydraulic properties of loess for landslide prediction:A study on variations in loess landslides in Lanzhou,Dingxi,and Tianshui,China
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作者 Gao-chao Lin wei liu Xing Su 《China Geology》 CAS CSCD 2024年第2期291-302,共12页
Loess has distinctive characteristics,leading to frequent landslide disasters and posing serious threats to the lives and properties of local re sidents.The involvement of water repre sents a critical factor in induci... Loess has distinctive characteristics,leading to frequent landslide disasters and posing serious threats to the lives and properties of local re sidents.The involvement of water repre sents a critical factor in inducing loess landslides.This study focuses on three neighboring cities sequentially situated on the Loess Plateau along the direction of aeolian deposition of loess,namely Lanzhou,Dingxi,and Tianshui,which are densely populated and prone to landslide disasters.The variations in hydraulic properties,including water retention capacity and permeability,are investigated through Soil Water Characteristic Curve(SWCC)test and hydraulic conductivity test.The experimental findings revealed that Tianshui loess exhibited the highest water retention capacity,followed by Dingxi loess,while Lanzhou loess demonstrated the lowest water retention capacity.Contrastingly,the results for the saturated permeability coefficient were found to be the opposite:Tianshui loess showed the lowest permeability,whereas Lanzhou loess displayed the highest permeability.These results are supported and analyzed by scanning electron microscopy(SEM)observation.In addition,the water retention capacity is mathematically expressed using the van Genuchten model and extended to predict unsaturated hydraulic properties of loess.The experimental results exhibit a strong accordance with one another and align with the regional distribution patterns of disasters. 展开更多
关键词 LOESS LANDSLIDE Hydraulic properties Water retention capacity and permeability Soil Water Characteristic Curve(SWCC) Hydraulic conductivity Van Genuchten model Hydrogeological engineering Geological hazards prevention engineering
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Extraction of the key infrared radiation temperature features concerning stress and crack evolution of loaded rocks
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作者 wei liu Liqiang Ma +4 位作者 Michel Jaboyedoff Marc-Henri Derron Qiangqiang Gao Fengchang Bu Hai Sun 《International Journal of Mining Science and Technology》 SCIE EI CAS CSCD 2024年第8期1059-1081,共23页
The infrared radiation temperature(IRT)variation concerning stress and crack evolution of rocks is a critical focus in rock mechanics domain and engineering disaster warning.In this paper,a methodology to extract the ... The infrared radiation temperature(IRT)variation concerning stress and crack evolution of rocks is a critical focus in rock mechanics domain and engineering disaster warning.In this paper,a methodology to extract the key IRT features related to stress and crack evolution of loaded rocks is proposed.Specifically,the wavelet denoising and reconstruction in thermal image sequence(WDRTIS)method is employed to eliminate temporal noise in thermal image sequences.Subsequently,the adaptive partition temperature drift correction(APTDC)method is introduced to alleviate temperature drift.On this basis,the spatial noise correction method based on threshold segmentation and adaptive median filtering(OTSU-AMF)is proposed to extract the key IRT features associated with microcracks of loaded rocks.Following temperature drift correction,IRT provides an estimation of the thermoelastic factor in rocks,typically around 5.29×10^(-5) MPa^(-1) for sandstones.Results reveal that the high-temperature concentrated region in cumulative thermal images of crack evolution(TICE)can elucidate the spatiotemporal evolution of localized damage.Additionally,heat dissipation of crack evolution(HDCE)acquired from TICE quantifies the progressive failure process of rocks.The proposed methodology enhances the reliability of IRT monitoring results and provides an innovative approach for conducting research in rock mechanics and monitoring engineering disasters. 展开更多
关键词 Infrared radiation(IR) Temperature drift Spatial background noise Rock fracture Average infrared radiation temperature(AIRT) Heat dissipation of crack evolution(HDCE)
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Development characteristics and controlling factors of fractures in lacustrine shale and their geological significance for evaluating shale oil sweet spots in the third member of the Shahejie Formation in the Qikou Sag, Bohai Bay Basin
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作者 Xu Zeng Tao Yang +5 位作者 Jian-wei Feng Cong-Sheng Bian Ming Guan wei liu Bing-Cheng Guo Jin Dong 《Petroleum Science》 SCIE EI CAS CSCD 2024年第2期791-805,共15页
Natural fractures are critical for shale oil and gas enrichment and development. Due to the extremely high heterogeneity of shale, the factors controlling the formation of internal fractures, especially horizontal fra... Natural fractures are critical for shale oil and gas enrichment and development. Due to the extremely high heterogeneity of shale, the factors controlling the formation of internal fractures, especially horizontal fractures, remain controversial. In this study, we integrate thin section analysis and microcomputed tomography(CT) data from several lacustrine shale samples from the third member(Es3) of the Shahejie Formation, Qikou Sag, Bohai Bay Basin, to assess the fractures in detail. The goal is to reveal the development characteristics, controlling factors, and geological significance for evaluating sweet spots in a shale oil play. The fractures in the Es3contain high-angle structural and horizontal bed-parallel fractures that are mostly shear and extensional. Various factors influence fracture development,including lithofacies, mineral composition, organic matter content, and the number of laminae. Structural fractures occur predominantly in siltstone, whereas bed-parallel fractures are abundant in laminated shale and layered mudstone. A higher quartz content results in higher shale brittleness, causing fractures, whereas the transformation between clay minerals contributes to the development of bedparallel fractures. Excess pore pressure due to hydrocarbon generation and expulsion during thermal advance can cause the formation of bed-parallel fractures. The density of the bed-parallel and structural fractures increases with the lamina density, and the bed-parallel fractures are more sensitive to the number of laminae. The fractures are critical storage spaces and flow conduits and are indicative of sweet spots. The laminated shale in the Es3with a high organic matter content contains natural fractures and is an organic-rich, liquid-rich, self-sourced shale play. Conversely, the siltstone, massive mudstone, and argillaceous carbonate lithofacies contain lower amounts of organic matter and do not have bed-parallel fractures. However, good reservoirs can form in these areas when structural fractures are present and the source, and storage spaces are separated. 展开更多
关键词 FRACTURES Development characteristics Controlling factors Shale oil Sweet spot
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Hydraulic fracturing behaviors of shale under coupled stress and temperature conditions simulating different burial depths
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作者 Qin Zhou Zheming Zhu +6 位作者 wei liu Huijun Lu Zidong Fan Xiaofang Nie Cunbao Li Jun Wang Li Ren 《International Journal of Mining Science and Technology》 SCIE EI CAS CSCD 2024年第6期783-797,共15页
Fracture propagation in shale under in situ conditions is a critical but poorly understood mechanical process in hydraulic fracturing for deep shale gas reservoirs. To address this, hydraulic fracturing experiments we... Fracture propagation in shale under in situ conditions is a critical but poorly understood mechanical process in hydraulic fracturing for deep shale gas reservoirs. To address this, hydraulic fracturing experiments were conducted on hollow double-wing crack specimens of the Longmaxi shale under conditions simulating the ground surface(confining pressure σ_(cp)=0, room temperature(Tr)) and at depths of 1600 m(σ_(cp)=40 MPa, Ti=70 ℃) and 3300 m(σ_(cp)=80 MPa, high temperature Ti=110 ℃) in the study area.High in situ stress was found to significantly increase fracture toughness through constrained microcracking and particle frictional bridging mechanisms. Increasing the temperature enhances rather than weakens the fracture resistance because it increases the grain debonding length, which dissipates more plastic energy and enlarges grains to close microdefects and generate compressive stress to inhibit microcracking. Interestingly, the fracture toughness anisotropy in the shale was found to be nearly constant across burial depths, despite reported variations with increasing confining pressure. Heated water was not found to be as important as the in situ environment in influencing shale fracture. These findings emphasize the need to test the fracture toughness of deep shales under coupled in situ stress and temperature conditions rather than focusing on either in situ stress or temperature alone. 展开更多
关键词 Hydraulic fracturing Fracture toughness SHALE ANISOTROPY Deep rock mechanics
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Transcriptional regulation of MdPIN7 by MdARF19 during gravityinduced formation of adventitious root GSA in self-rooted apple stock
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作者 Zenghui Wang Xuemei Yang +5 位作者 Linyue Hu wei liu Lijuan Feng Xiang Shen Yanlei Yin Jialin Li 《Horticultural Plant Journal》 SCIE CAS CSCD 2024年第5期1073-1084,共12页
Self-rooted apple stock is widely used for apple production.However,the shallowness of the adventitious roots in self-rooted apple stock leads to poor performance in the barren orchards of China.This is because of the... Self-rooted apple stock is widely used for apple production.However,the shallowness of the adventitious roots in self-rooted apple stock leads to poor performance in the barren orchards of China.This is because of the considerable difference in the development of a gravitropic set-point angle(GSA)between self-rooted apple stock and seedling rootstock.Therefore,it is crucial to study the molecular mechanism of adventitious root GSA in self-rooted apple stock for breeding self-rooted and deep-rooted apple rootstock cultivars.An apple auxin response factor MdARF19 functioned to establish the adventitious root GSA of self-rooted apple stock in response to gravity and auxin signals.MdARF19 bound directly to the MdPIN7 promoter,activating its transcriptional expression and thus regulating the formation of the adventitious root GSA in 12-2 self-rooted apple stock.However,MdARF19 influenced the expression of auxin efflux carriers(MdPIN3 and MdPIN10)and the establishment of adventitious root GSA of self-rooted apple stock in response to gravity signals by direct activation of MdFLP.Our findings provide new information on the transcriptional regulation of MdPIN7 by auxin response factor MdARF19 in the regulation of the adventitious root GSA of self-rooted apple stock in response to gravity and auxin signals. 展开更多
关键词 APPLE Self-rooted stock GRAVITY MdARF19 MdPIN7 Gravitropic set-point angle Transcriptional regulation
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Yr5-virulent races of Puccinia striiformis f.sp.tritici possess relative parasitic fitness higher than current main predominant races and potential risk
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作者 Gensheng Zhang Mudi Sun +4 位作者 Xinyao Ma wei liu Zhimin Du Zhensheng Kang Jie Zhao 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2024年第8期2674-2685,共12页
Wheat stripe rust,caused by Puccinia striiformis f.sp.tritici(Pst),is one of the most destructive fungal diseases of wheat,and seriously threatens safe production of the crop worldwide.In China,new races historically ... Wheat stripe rust,caused by Puccinia striiformis f.sp.tritici(Pst),is one of the most destructive fungal diseases of wheat,and seriously threatens safe production of the crop worldwide.In China,new races historically appeared and rapidly developed to be predominant races and have resulted in ineffectiveness and replacement of wheat resistance cultivars as well as massive reduction in yield.In the present study,the relative parasitic fitness of the two newlyemerged Yr5-virulent races(TSA-6 and TSA-9)were compared with those of four currently predominant Chinese races(CYR31,CYR32,CYR33,and CYR34)based on evaluation on 10 Chinese wheat cultivars.As a result,there were significant differences in the relative parasitic fitness parameters among overall tested races based on multiple comparison(LSD)analysis(P<0.05).The principal component analysis(PCA)of overall parasitic fitness parameters indicated that the sporulation ability,infection and spore survivability,expansion capacity,and potential pathogenicity were the most important parasitic fitness attributes of the tested races.Based on the establishment of extracted three principal components and a comprehensive factor score mathematical models,evaluations of the parasitic fitness attributes of tested races showed that the level of relative parasitic fitness of the tested six races was:CYR32(1.15)>TSA-9(0.95)>TSA-6(0.92)>CYR34(0.29)>CYR31(–1.54)>CYR33(–1.77).The results indicated that two Yr5-virulent races TSA-9 and TSA-6 possessed relative parasitic fitness higher than races CYR34,CYR31,and CYR33,but lower than race CYR32,and have potential risks in developing to be predominant races.Therefore,continual monitoring of both Yr5-virulent races,and their variants is needed.The use of wheat cultivars(lines)with Yr5 resistance gene singly in wheat breeding is essential for being avoided,and is suggested to combine with other effective stripe rust resistance genes. 展开更多
关键词 wheat stripe rust Puccinia striiformis f.sp.tritici parasitic fitness Yr5 new race
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Antibody Levels and Infection Status of Pertussis in the Population under Pertussis Resurgence in Guangxi in 2018:A Cross-Sectional Survey
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作者 Liang Liang Qiuyun Deng +6 位作者 Lili Deng Jinghang wei Shiyi Chen Yizhi wei Yuyan Ma Yue Qin wei liu 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 2024年第6期628-638,共11页
Objective Pertussis cases have increased markedly since 2018 in Guangxi.The aim of this study was to evaluate antibody levels and the infection status of pertussis in the resident population.Method A total of 10,215 s... Objective Pertussis cases have increased markedly since 2018 in Guangxi.The aim of this study was to evaluate antibody levels and the infection status of pertussis in the resident population.Method A total of 10,215 serum samples from residents were collected from August-November 2018 and tested for anti-pertussis IgG and toxin IgG using the enzyme-linked immunosorbent assay(ELISA).Results Of the collected samples,1,833(17.94%)tested positive for anti-pertussis IgG,with the median concentration of 16.06 IU/mL.Antibody level<10 IU/mL accounted for more than 60%in children under 4 years of age,but declined with age,whereas the percentages of the other three levels(10-40,40-50,and≥50 IU/mL)increased almost with age(P<0.001).Moreover,7,924 samples were selected for anti-pertussis toxin IgG,of which 653(8.24%)tested positive(≥40 IU/mL)with the median concentration of 5.89 IU/mL,and 204 participants(2.56%)had recent pertussis infection(≥100 IU/mL).Among the different age groups,the highest rates of positivity and recent infection were observed at 11-20 years of age,the lowest positivity rate at 5 years of age,and the lowest recent infection rate at 4 years of age(P<0.001,P=0.005,respectively).Conclusion The survey results showed that all age groups in Guangxi lacked immunity against pertussis,which was one of the main factors contributing to the resurgence of pertussis in 2018.In addition,the prevalence of pertussis is relatively high in Guangxi,and its incidence is seriously underestimated,especially in adolescents and adults. 展开更多
关键词 Pertussis resurgence Anti-pertussis IgG Anti-pertussis toxin IgG Antibody level Infection status
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