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外加能场辅助搅拌摩擦焊研究现状

焊接学报 2024年第4期45卷 109-119,I0009,I0010页

作者：孙广达闫中宪周利高福洋吕逸帆哈尔滨工业大学先进焊接与连接国家重点实验室哈尔滨150001 哈尔滨工业大学(威海) 山东省特种焊接技术重点实验室威海264209 中国船舶重工集团公司第七二五研究所洛阳471000

搅拌摩擦焊作为先进固相连接技术,广泛应用于航空航天等领域,轻质高强材料及异种材料连接对常规搅拌摩擦焊的发展提出了新的挑战.近年来,外加能场辅助搅拌摩擦焊技术的兴起有效地解决了异种材料连接中塑化程度不匹配和界面金属间化合物... 详细信息

搅拌摩擦焊作为先进固相连接技术,广泛应用于航空航天等领域,轻质高强材料及异种材料连接对常规搅拌摩擦焊的发展提出了新的挑战.近年来,外加能场辅助搅拌摩擦焊技术的兴起有效地解决了异种材料连接中塑化程度不匹配和界面金属间化合物导致接头脆化的问题.同时,这一技术也为解决高熔点材料流变应力大、塑性变形能力差以及焊具磨损严重、焊接效率低等问题提供了新的思路.文中综述了外加能场辅助搅拌摩擦焊的研究现状,包括感应加热、激光加热、电流加热、电弧加热和超声辅助等,从过程产热、材料流动、组织性能调控和耦合作用机制等方面分析了热能和机械能对接头微观组织和性能的影响规律,同时对未来的研究方向进行展望.

关键词：高熔点材料异种材料能场辅助搅拌摩擦焊塑性材料流动

小脑幕上无症状脑膜瘤的临床特征分析(附163例报告)

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中华神经外科杂志 2024年第6期40卷 553-558页

作者：杨明煦吕一帆邓宇轩杜超于兰冰任同张扬初君盛郝淑煜季楠首都医科大学附属北京天坛医院神经外科学中心北京100070

目的探讨小脑幕上无症状脑膜瘤的临床特征.方法回顾性分析2019年1月至2023年8月于首都医科大学附属北京天坛医院神经外科学中心确诊的无症状脑膜瘤患者的临床资料,共163例,其中122例为手术治疗者,41例为于门诊随访观察者.观察患者的性... 详细信息

目的探讨小脑幕上无症状脑膜瘤的临床特征.方法回顾性分析2019年1月至2023年8月于首都医科大学附属北京天坛医院神经外科学中心确诊的无症状脑膜瘤患者的临床资料,共163例,其中122例为手术治疗者,41例为于门诊随访观察者.观察患者的性别、年龄分布,肿瘤部位、大小,组织病理学类型、世界卫生组织(WHO)分级等.结果163例患者中,男51例,女112例,男女比例为1.0:2.2;发病年龄为(53.25±10.75)岁(22~80岁),其中50~59岁患者的占比最高(41.72%,68例),其次为60~69岁患者(22.09%,36例);男、女患者的年龄差异无统计学意义(P=0.127).肿瘤位于大脑凸面最多见,占73.62%(120例),其次为矢状窦旁,占16.56%(27例),而位于大脑镰旁、脑室、小脑幕者均较少见.肿瘤体积的M(Q_(1),Q_(3))为6.08(1.87,15.78)cm^(3).行手术切除的122例患者中,WHO 1级97例(79.51%)、2级21例(17.21%)、3级4例(3.28%);组织病理学类型中以移行型(36.07%,44例)、纤维型(25.41%,31例)及内皮型(17.21%,21例)多见;纤维型脑膜瘤的分布部位最为广泛(各部位均可见),其次为移行型和内皮型脑膜瘤.122例患者中,术后21例(17.20%)发生手术相关的并发症,其中WHO 1级、2级、3级患者分别占8.20%(10例)、6.56%(8例)、2.46%(3例).结论初步观察显示,小脑幕上无症状脑膜瘤可能与脑膜瘤的整体特征存在一定差异.

关键词：脑膜瘤幕上肿瘤无症状疾病疾病特征

极光激酶A抑制剂对胶质母细胞瘤细胞增殖和B7-H3蛋白表达影响的实验研究

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中华神经外科杂志 2024年第4期40卷 406-413页

作者：刘金秋蒲焯楠邓宇轩吕一帆张绍东郝淑煜季楠万虹冯洁首都医科大学北京市神经外科研究所北京100070 首都医科大学附属北京天坛医院神经外科学中心北京100070

目的探讨极光激酶A(AURKA)抑制剂对胶质母细胞瘤(GBM)的细胞增殖和免疫检查点B7-H3表达的影响。方法基于中国胶质瘤基因组图谱(CGGA)计划数据库(共325例患者),分析AURKA mRNA的表达水平与肿瘤的病理学类型、世界卫生组织(WHO)级别、原/... 详细信息

目的探讨极光激酶A(AURKA)抑制剂对胶质母细胞瘤(GBM)的细胞增殖和免疫检查点B7-H3表达的影响。方法基于中国胶质瘤基因组图谱(CGGA)计划数据库(共325例患者),分析AURKA mRNA的表达水平与肿瘤的病理学类型、世界卫生组织(WHO)级别、原/复发状态、患者的生存期、O°-甲基鸟嘌呤-DNA-甲基转移酶(MGMT)甲基化、异柠檬酸脱氢酶(IDH)突变及染色体1p19q共缺失的相关性。比较AURKA mRNA在不同病理学类型、不同WHO级别,以及原发与复发性脑胶质瘤中表达的差异。绘制Kaplan-Meier生存曲线以比较不同AURKA mRNA表达水平的脑胶质瘤患者生存期差异。通过单因素和多因素Cox回归模型分析探讨AURKAmRNA表达水平、IDH突变、染色体1p19q共缺失、发病年龄、放疗、化疗、WHO级别及原/复发状态对脑胶质瘤患者生存期的影响。绘制受试者工作特征(ROC)曲线并计算曲线下面积(AUC),以确定AURKA mRNA表达水平对脑胶质瘤患者生存期的预测价值。收集首都医科大学附属北京天坛医院神经外科学中心接受手术治疗患者的脑胶质瘤组织样本,其中低级别胶质瘤(LGG)4例,CBM4例;通过蛋白质免疫印迹(WB)法检测AURKA在肿瘤组织样本中的表达情况。采用AURKA抑制剂alisertib处理人CBM细胞株U87-MG,将其分为对照组(以DMSO处理)和alisertib处理组(以5μmol/Lalisertib处理)。采用CCK-8法和结晶紫染色方法分别检测alisertib对细胞活性和克隆形成的影响。采用WB法检测alisertib对AURKA、磷酸化AURKA和B7-H3蛋白表达的影响。应用流式细胞术检测alisertib对GBM细胞膜蛋白B7-H3表达的影响。结果CGGA计划数据库分析结果表明,AURKA mRNA在CBM中的表达水平高于星形胶质细胞瘤和少突胶质细胞瘤(均P<0.001);在WHO2、3及4级胶质瘤组间,AURKA mRNA的表达水平随WHO级别的升高而增加(P<0.001);AURKA mRNA在复发性胶质瘤中的表达水平高于原发性胶质瘤(t=4.50,P<0.001)。Kaplan-Meier生存曲线分析结果显示,AURKA mRNA高表达组的患者比低表达组生存期短(均P<0.05)。单因素Cox回归分析结果显示,AURKA mRNA的表达水平、IDH突变、染色体1p19q共缺失、发病年龄、放疗、化疗、WHO级别及原/复发状态均为脑胶质瘤患者生存期的影响因素(均P<0.05);多因素Cox回归模型分析结果显示,AURKA mRNA高表达、复发状态、WHO高级别、发病年龄偏高、未接受化疗及无染色体1p19q共缺失均为脑胶质瘤患者生存期的独立危险因素(均P<0.05)。ROC曲线分析显示,AURKA mRNA表达水平预测脑胶质瘤患者1年、3年和5年生存期的AUC(95%CI)分别为0.78(0.72~0.83)、0.85(0.80~0.89)、0.84(0.79~0.89)。临床样本的WB结果显示,人GBM组织中AURKA蛋白的表达水平高于LGG(t=2.62,P=0.040)。CCK-8实验结果显示,alisertib处理24、48、72h后均显著抑制了U87-MG细胞的活性(均P<0.05)。克隆形成实验结果显示,alisertib明显抑制了U87-MG细胞的克隆形成(t=9.30,P<0.001)。WB实验结果表明,alisertib处理组的磷酸化AURKA表达水平明显低于对照组(t=10.98,P<0.001),而B7-H3蛋白表达水平高于对照组(t=7.55,P=0.002)。流式细胞术检测结果显示,与对照组比较,alisertib处理组膜蛋白B7-H3的表达水平升高(t=20.04,P<0.001)。结论AURKA抑制剂alisertib可能能够抑制GBM的细胞增殖,并增强免疫检查点B7-H3的表达。

关键词：胶质母细胞瘤细胞增殖极光激酶A 免疫检查点 B7-H3蛋白

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TC4焊接接头热变形行为及组织演变研究

热加工工艺 2024年第5期53卷 129-135页

作者：朱晓宇廖志谦吕逸帆吴晓飞贾晓飞王志毅李新戴乐中国船舶集团有限公司第七二五研究所河南洛阳471023 海装驻洛阳地区军事代表室河南洛阳471023

基于Gleeble高温拉伸试验,研究TC4钛合金焊接接头在温度为700~950℃、应变速率为10-4~10-1s-1条件下的热变形行为,使用Arrhenius双曲正弦模型建立TC4焊接接头的热变形本构方程,并采用金相显微镜、SEM、EBSD等手段研究焊接接头在热变形... 详细信息

基于Gleeble高温拉伸试验,研究TC4钛合金焊接接头在温度为700~950℃、应变速率为10-4~10-1s-1条件下的热变形行为,使用Arrhenius双曲正弦模型建立TC4焊接接头的热变形本构方程,并采用金相显微镜、SEM、EBSD等手段研究焊接接头在热变形过程中的显微组织演变规律。结果表明:TC4焊接接头在热拉伸过程中的流变应力对变形温度和应变速率敏感,随变形温度的升高和应变速率的降低而降低;焊接接头的伸长率受变形温度和应变速率的耦合作用,随变形温度的升高和应变速率的降低而升高。通过本构方程计算得出焊接接头在(α+β)两相区的变形激活能为547.385 kJ/mol,软化机制为动态再结晶。随变形温度的升高,焊缝金属内部β相含量升高、大角度界面减少、几何必要位错密度降低,导致焊接接头的流变应力降低,伸长率升高。

关键词： TC4钛合金焊接接头高温拉伸流变应力本构方程显微组织

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State-of-the-art on resistance of bearing-type bolted connections in high strength steel

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Frontiers of Structural and Civil Engineering 2020年第3期14卷 569-585页

作者： Guoqiang LI yifan lyu Yanbo WANG State Key Laboratory for Disaster Reduction in Civil Engineering Tongji UniversityShanghai 200092China College of Civil Engineering Tongji UniversityShanghai 200092China

With the recent development of material science,high strength steel(HSS)has become a practical solution for landmark buildings and major *** current codes for design of bearing-type bolted connections of steel constructions were established based on the research of conventional *** the mechanical properties of HSS are different from those of conventional steels,more works should be done to develop the appropriate approach for the design of bearing-type bolted connections in HSS.A review of the research carried out on bearing-type bolted connections fabricated from conventional steel and HSS is *** up-to-date tests conducted at Tongji University on four connection types fabricated from three grades of HSS with nominal yield strengths of 550,690,and 890 MPa are *** previous research on failure modes,bearing resistance and the design with consideration of bolt hole elongation are *** is found that the behavior of bolted connections in HSS have no drastic difference compared to that of conventional steel *** the ductility is reduced,plastic deformation capacity of HSS is sufficient to ensure the load redistribution between different bolts with normal construction *** is also found that behavior of each bolt of multi-bolt connections arranged in perpendicular to load direction is almost identical to that of a single-bolt connection with the same end *** connections with bolts arranged in parallel to load direction,the deformation capacity of the whole connection depends on the minimum value between the end distance and the spacing distances in load *** comparison with existing design codes shows that Eurocode3 and Chinese GB50017-2017 are conservative for the design of bolted connections in HSS while AISC 360-16 may overestimate the bearing resistance of bolted connections.

关键词： High strength steel bolted connection bearing behavior design codes

Distal margin distance in radical resection of locally advanced rectal cancer after neoadjuvant therapy

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Chinese Journal of Cancer Research 2024年第2期36卷 226-232页

作者： Jun Luo Mingxuan Zhu Long Zhao Meiwen He Bei Li yifan Liu Yuhan Sun Guoqing lyu Zhanlong Shen Department of Gastrointestinal Surgery Peking University Shenzhen HospitalShenzhen 518036China Department of Gastroenterological Surgery Laboratory of Surgical OncologyBeijing Key Laboratory of Colorectal Cancer Diagnosis and Treatment ResearchPeking University People's HospitalBeijing 100044China School of Medicine the Chinese University of Hong KongShenzhen 518172China

Colorectal cancer has a high incidence and mortality rate in China, with the majority of cases being middle and low rectal cancer. Surgical intervention is currently the main treatment modality for locally advanced rectal cancer, with the common goal of improving oncological outcomes while preserving function. The controversy regarding the circumferential resection margin distance in rectal cancer surgery has been resolved. With the promotion of neoadjuvant therapy concepts and advancements in technology, treatment strategies have become more *** tumor downstaging, there is an increasing trend towards extending the safe distance of distal rectal margin. This provides more opportunities for patients with low rectal cancer to preserve their anal ***, there is currently no consensus on the specific distance of distal resection margin.

关键词： Colorectal cancer distal resection margin neoadjuvant therapy

The evolving views of hematopoiesis:from embryo to adulthood and from in vivo to in vitro

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Journal of Genetics and Genomics 2024年第1期51卷 3-15页

作者： yifan Zhang Feng Liu Shandong Provincial Key Laboratory of Animal Cell and Developmental Biology School of Life SciencesShandong UniversityQingdaoShandong 266237China State Key Laboratory of Membrane Biology Institute of ZoologyInstitute for Stem Cell and RegenerationUniversity of Chinese Academy of SciencesChinese Academy of SciencesBeijing 100101China

The hematopoietic system composed of hematopoietic stem and progenitor cells(HSPCs)and their differentiated lineages serves as an ideal model to uncover generic principles of cell fate *** gastrulation onwards,there successively emerge primitive hematopoiesis(that produces specialized he-matopoietic cells),pro-definitive hematopoiesis(that produces lineage-restricted progenitor cells),and definitive hematopoiesis(that produces multipotent HSPCs).These nascent lineages develop in several transient hematopoietic sites and finally colonize into lifelong hematopoietic *** development and maintenance of hematopoietic lineages are orchestrated by cell-intrinsic gene regulatory networks and cell-extrinsic microenvironmental *** to the progressive methodology(e.g.,high-throughput lineage tracing and single-cell functional and omics analyses),our understanding of the developmental origin of hematopoietic lineages and functional properties of certain hematopoietic organs has been updated;meanwhile,new paradigms to characterize rare cell types,cell heterogeneity and its causes,and comprehensive regulatory landscapes have been ***,we review the evolving views of HSPC biology during developmental and postnatal ***,we discuss recent advances in the in vitro induction and expansion of HSPCs,with a focus on the implications for clinical applications.

关键词： Hematopoietic stem and progenitor cell Developmental hematopoiesis Postnatal hematopoiesis In vitro hematopoiesis

Theoretical insights of the pharmaceutical compound fluoxetine in water:Role in direct photolysis and indirect photolysis by free radicals

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Journal of Environmental Sciences 2024年第8期142卷 269-278页

作者： Ying Lu Se Wang yifan Shen School of Environmental Science and Engineering Collaborative Innovation Center of Atmospheric Environment and Equipment TechnologyJiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution ControlNanjing University of Information Science and TechnologyNanjing 210044China

The frequent detection of pharmaceutical compounds in the environment has led to a growing awareness,which may pose a major threat to the aquatic *** this study,photodegradation(direct and indirect photolysis)of two different dissociation states of fluoxetine(FLU)was investigated in water,mainly including the determination of photolytic transition states and products,and the mechanisms of indirect photodegradation with·OH,CO_(3)^(*-)and NO_(3)^(*).The main direct photolysis pathways are defluorination and C–C bond *** addition,the indirect photodegradation of FLU in water is mainly through the reactions with·OH and NO_(3)^(*),and the photodegradation reaction with CO_(3)^(*-)is relatively difficult to occur in the water *** results provide a theoretical basis for understanding the phototransformation process of FLU in the water environment and assessing its potential risk.

关键词： Fluoxetine Photochemical mechanism Direct photolysis Free radical reaction DFT

State-Based Opacity Verification of Networked Discrete Event Systems Using Labeled Petri Nets

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IEEE/CAA Journal of Automatica Sinica 2024年第5期11卷 1274-1291页

作者： yifan Dong Naiqi Wu Zhiwu Li The authors are with the Institute of Systems Engineering Macao University of Science and TechnologyTaipa 999078MacaoChina

The opaque property plays an important role in the operation of a security-critical system,implying that pre-defined secret information of the system is not able to be inferred through partially observing its *** paper addresses the verification of current-state,initial-state,infinite-step,and K-step opacity of networked discrete event systems modeled by labeled Petri nets,where communication losses and delays are *** on the symbolic technique for the representation of states in Petri nets,an observer and an estimator are designed for the verification of current-state and initial-state opacity,***,we propose a structure called an I-observer that is combined with secret states to verify whether a networked discrete event system is infinite-step opaque or K-step *** to the utilization of symbolic approaches for the state-based opacity verification,the computation of the reachability graphs of labeled Petri nets is avoided,which dramatically reduces the computational overheads stemming from networked discrete event systems.

关键词： infinite system symbolic