头穴丛刺对慢性脑缺血大鼠认知功能障碍及VEGF蛋白表达的影响

目的:观察头穴丛刺对慢性脑缺血大鼠认知功能障碍及VEGF表达的影响,并探讨其作用机制.方法:采取国内改进的双侧颈总动脉永久性结扎法制备慢性脑缺血大鼠模型,制备成功的大鼠随机分为3组:缺血组、头穴丛刺组、尼莫地平组.Morris水迷宫检测大鼠学习记忆能力,HE染色观察大鼠额叶皮层和海马区的细胞形态变化,免疫组化检查VEGF蛋白表达的情况.结果:与假手术组相比,缺血组大鼠逃避潜伏期明显延长(P＜0.05);与缺血组大鼠比较,头穴丛刺组和尼莫地平组大鼠额叶皮层和海马区VEGF蛋白表达明显增多(P＜0.05).结论:头穴丛刺法能上调VEGF在慢性脑缺血大鼠中的表达,减轻大鼠的缺血缺氧情况,改善慢性脑缺血大鼠认知功能障碍的状况.     

缺氧微环境诱导胶质母细胞瘤耐药机制研究进展

胶质母细胞瘤（glioblastoma,GBM）的耐药性是导致其临床治疗失败的主要原因。目前,诸多研究认为肿瘤内部缺氧的微环境能够诱导GBM对放化疗的抵抗。GBM的生长极为迅速,贫瘠的氧供不能满足其对氧气的需求,缺氧的微环境由此形成。缺氧可通过不同机制影响GBM的耐药性。本文将根据缺氧微环境的形成与缺氧诱导GBM耐药的机制进行综述。      

肺癌患者外周血CK19mRNA与微转移的实验研究

目的：检测非小细胞肺癌（NSCLC）患者外周血CK19mRNA的表达情况,探讨其诊断NSCLC外周血微转移的临床意义。方法：选取初治NSCLC患者40例及健康志愿者50例,用实时荧光定量RT—PCR方法检测外周血CK19mRNA,相对定量分析结果。结果：肺癌组与健康对照组CK19mRNA阳性表达率分别为72．5％（29／40）、14．0％（7／50）,差异显著（P〈0．05）;相对表达量分别为1．69±0．44、0．28±0．12,有显著差异（P〈0．05）。阳性表达率与原发肿瘤部位、原发肿瘤大小、临床分期、分化程度及病理类型无相关性;相对表达量在中央型、T3＋T4、Ⅲ期＋Ⅳ期及低分化患者数值较高,但不具有统计学意义,鳞癌患者高于腺癌,且有显著差异（P〈0．05）。结论：CK19mRNA作为Real—time RT—PCR法检测NSCLC外周血微转移的分子标记物,具有一定临床应用价值,但特异性仍需提高,应进一步扩大样本进行研究及随访。相对定量分析是一种值得推荐、准确简便的荧光实时相对定量方法。     

腹腔镜基本技能的模拟训练

腹腔镜基本技能的培训是微创外科发展的必然要求,哈尔滨医科大学附属第四医院微创外科针对从事微创外科的医务工作者,通过讲解有关腹腔镜基本理论知识,并与模拟训练和手术观摩等方式相结合,教法灵活,使学员真正掌握这门微创技术。     

周细胞的研究进展

周细胞是一种多能细胞,可以向骨、软骨等组织分化;具有收缩能力,从而调节微环境的灌流量和通透性;还能和内皮细胞相互作用,参与血管形成和创伤愈合。周细胞的功能失调和许多微血管疾病以及肿瘤的扩散相关。一直以来,对周细胞的存在以及功能有所忽略,最近才对其有一定的认识。本文就周细胞的定位、结构、标记物、功能、相关的信号通路以及在肿瘤中所起的作用做一简单的介绍。     

三阶段临床教学模式在全科医师规范化培训眩晕疾病鉴别中的应用

眩晕是全科医生临床最为常见的症状之一。在全科医师规范化培训眩晕疾病诊疗的理论与实践中,课题组成员中的神经内科眩晕亚专业诊疗组医师,分析了眩晕疾病的流行病学特征及理论与实践教学现状,以多学科为基础,提出符合学员对疾病认识规律的“打牢基础、巩固强化、提升技能”三阶段教学模式并实施。帮助全科医生熟悉眩晕病因和诊疗路径,完善多学科知识结构,建立科学的临床诊疗思维,提高全科医生对眩晕相关疾病的诊治水平,取得良好效果,对改善患者预后发挥积极作用。     

递进式案例教学在口腔修复学授课中的应用

口腔修复学教学具有实践性强、内容抽象、知识复杂等特征。从临床（教学）资源的充足程度而言,案例教学更易于在教学型医院实施。在此围绕哈尔滨医科大学附属第一医院本科生的口腔修复学教学序列流程,在本科理论授课、课间实习和临床生产实习中递进式引入案例教学,增加了学生接触临床完整案例的机会,以培养学生从事临床工作所需的实际能力。     

基于导师视角浅析MRI影像 PBL教学策略框架

影像学科对从业人员的复合能力要求,使得MRI的教学环节必须认真思考如何有效地汇总整理纷繁复杂的跨专业领域知识。以问题为基础的学习（PBL）作为系统的教学方案其应具有明确的价值取向、操作原则、工作流程。只有遵循上述规则性的要求,结合MRI专业对于复合型人才的培养目标与实践,才能最大程度发挥PBL在MRI领域中的效能。本研究通过系统梳理PBL教学的本质特征,总结MRI专业特征以及培养方案,提出导师应具备的教学策略框架,以期进一步将PBL理念应用于实践教学环节,提升MRI教学效能,推动我国医疗影像教学和实践的发展。     

Exploring Hydrogen Incorporation into the Nb4AlC3 MAX Phases: Ab Initio Calculations

The Nb₄AlC₃ MAX phase can be regarded as a TMC structure with stacking faults, which has great potential as a novel solid hydrogen storage material. Herein, we used ab initio calculations for understanding the hydrogen incorporation into Nb₄AlC₃ MAX phases, including equilibrium structural characteristics, energy changes, electronic structures, bonding characteristics, and diffusion paths. According to the calculated results, H has thermal stability in the interstice of the Nb-Al layer, and the most probable insertion site is an octahedron (3-site) composed of three Nb atoms and three Al atoms. When C vacancies are introduced, the Nb-C layer has a specific storage capacity for H. In addition, Al vacancies can also be used as possible sites for H incorporation. Moreover, the introduction of vacancies significantly increase the hydrogen storage capacity of the MAX phase. According to the electronic structure and bonding characteristics, the excellent hydrogen storage ability of the Nb₄AlC₃ structure may be due to the formation of ionic bonds between H and Nb/Al. It is worth noting that the H-Al bond in the 1-site is a covalent bond and an ionic bond key mixture. The linear synchronous transit optimization study shows that only H diffusion in Al vacancies is not feasible. In conclusion, the Nb-Al layer in Nb₄AlC₃ can provide favorable conditions for the continuous insertion and subsequent extraction of H, while the vacancy structure is more suitable for H storage. Our work provides solid theoretical results for understanding the hydrogen incorporation into Nb₄AlC₃ MAX phases that can be helpful for the design of advanced hydrogen storage materials.     

In-Situ Measurement and Slow-Tool-Servo Compensation Method of Roundness Error of a Precision Mandrel

This paper describes a method for measuring and compensating the roundness error of a larger mandrel manufactured by an ultra-precision diamond-turning lathe aimed to obtain a calibration cylinder with a roundness of less than 0.1 μm. The diamond-turning machine has a cross-stacked hydrostatic guideway, produces a cutting depth and feed movement direction, and a dual-spindle system that is firmly connected to the bed. Due to the good repeatability of aerostatic spindles, only in situ rather than online real-time measurements are required. To this end, three high-precision capacitance displacement sensors were utilized to detect the cross-section of the workpiece and the time domain via the three-point error separation technique to separate the roundness error from the rotation motion error. The slow tool servo (STS) cutting technique was employed to compensate for the roundness error, which did not require extra axes, only the excellent dynamic response of the feed axis; hence, the servo control parameters could be suitably adjusted. The experimental results reveal that the low-order harmonic error, often caused by aerostatic spindles, is almost removed completely. For this particular lathe, the experiments indicate that about 60% of the rotational error motion is compensated, and the roundness error is reduced to less than 0.1 μm, which is evaluated by the least-squares circle method.