人生殖道疣和子宫颈癌中病毒基因检测及超微结构研究

本实验用透射电镜观察了32例子宫颈癌,6例宫颈湿疣和2例外阴疣的超微结构,同时以～(32)P-dCTP标记的HPV 16 DNA为探针,检测了宫颈癌活检组织中的病毒DNA相关序列。电镜下,生殖道疣各例均可见典型凹空细胞病变,细胞核内的核小体,染色质之间颗粒,染色质周围颗粒显著增多。核酸杂交显示23例宫颈癌组织中存在病毒DNA相关序列。杂交呈强阳性及中强阳性组织中的癌细胞核中的核小体明显多于弱阳性及阴性标本。。     

去膜精子染色质诱导体外重建核及其lamina成份分析

去膜精子染色质诱导体外重建核及其ｌａｍｉｎａ成份分析曲健，张传茂，翟中和（北京大学生命科学学院，北京１００８７１）本文利用非洲爪蟾去膜精子染色质和活化卵提取物为材料进行非细胞体系细胞核重建实验，结果成功地获得了体外重建核；并进一步利用免疫荧光和Ｗｅｓ...     

电镜放射自显影方法检测分布于染色质间颗粒内的RNA

快速分离大白鼠肝细胞,用H~3尿嘧啶处理,再孵育于无放射性尿嘧啶和DRB药内,用电镜放射自显影技术测定核放射性,在这些条件下显示染色质间颗粒被标记,并用低剂量Actinomycin D颗粒处理细胞,这些观察指出在DRB处理细胞内,染色质间颗粒是核仁RNA聚集或运输部位。染色质间颗粒(IG)存在于大多数细胞核的核质内,如形态学上已确定的结构,平均直径为200—250A,由细的原纤维联接成不同大小IG丛,用Bcrnhard选择性RNP染色法,IG显示强染色,本实验用DBR处理分离肝细胞后,出现了特殊的IG丛,这些IG丛含有核仁起源的RNA,亦证明了IG是核仁RNA的聚集或运输部位,但对IG     

盐离子浓度对HeLa细胞内提取的“30nm”染色质结构影响的电镜观察

染色质是遗传信息发挥作用的重要处所,其结构受到了广泛的关注。研究人员基于不同的实验材料和方法提出一些30 nm染色质纤维结构模型,但并没有形成一个统一的结论。本文选择人源Hela细胞作为实验材料,综合前人的实验方法,从细胞内提取纯化染色质"30 nm"纤维并进行电子显微观察,在不同Na+离子浓度盐溶液中对Hela细胞染色质"30 nm"纤维结构形态及折叠紧密程度的影响进行了分析。结果表明,在0～100 mmol/L Na+之间,随着盐浓度的升高,染色质结构折叠呈现逐渐紧密的趋势。与此同时,在提取染色质纤维的过程中可以通过调节Na+,Ca2+,Mg2+等盐离子浓度抑制Hela细胞内源性核酸酶的活性。本文结果为进一步研究30 nm染色质纤维的高级结构提供了有益的信息。     

电镜技术解析出30nm染色质的双螺旋结构

正2014年4月25日,中国科学院生物物理研究所朱平研究员和李国红研究员课题组在美国Science杂志上,以研究论文(Research Article)形式发表了题为"Cryo-EM study of the chromatin fiber reveals a double helix twisted by tetranucleosomal units"的学术论文,解析了30 nm染色质纤维的三维结构,提出了"左手双螺旋结构"模型。这一重大发现,受到国内外学者的密切关注。1一道憋了30年的难题DNA是细胞中遗传物质的载体,它究竟以什么     

大鼠淋巴结的透射电镜观察

对T、B淋巴细胞超微结构的鉴别目前意见不一,本文对大鼠淋巴结进行了透射电镜观察,看到可分四种细胞类型;①细胞表面较光滑,核较大,核浆比例较大,异染色质多,附于核膜下。胞质内核糖体非常丰富,有少量线粒体分散存在。此类细胞相当T淋巴细胞(图_2~1上)。②细胞表面也较光滑,核较前者小,核浆比例也较前者小,核内染色质与前者相似。胞质内有大量泡状或板层状粗面内质网,其间有散在的线粒体。此类细胞相当B淋巴细胞(图1下)③细胞表面伸出一些较长突起,相邻细胞突起间看到缝管连接。核椭圆或不甚规则,异染色质很少。胞质电子密度低,内有少量细长的粗面内质网,多分布于胞体的一侧,     

黑麦小孢子母细胞核基质的超显微结构观察

把黑麦的幼穗剪下插入含5％二甲基亚砜(DMSO)的Banner's盐溶液中。室温下培养24小时后,解剖出花药,按常规的超薄切片法制片。透射电子显微镜下观察发现小孢子母细胞核内出现类似微丝的微纤丝结构。这种结构粗约6-7nm,集合成微纤丝束,特异性地出现在凝线期的小孢子母细胞核中。在凝线期,染色质向核的一极集中,靠近核膜的区域由于染色质的转移变为透明区。微纤丝束通常分布在这种透明区。微纤丝束位于染色质附近,并与细胞核的长轴和染色质向极端运动的方向平行。在未经DMSO处理的小孢子母细胞中偶尔也可看到这种结构。文章讨论了黑麦小孢子母细胞核中微纤丝结构的生化本质和可能的作用。     

用激光在蚕卵上植入染色质引起变异

报道一种移植异种基因的新技术,它是用脉冲微束激光照射到置于显微镜下的活细胞,在细胞上造成微孔损伤,异种基因便被植入。我们在“龙角”蚕卵上植入“黑缟”蚕的某种染色质溶液,经过培育生长,成活率达90%以上,并出现了按预期目的特定变化的变异体。这种变异与用传统的针刺法植入染色质引起的变异完全一致。     

洋葱细胞周期中线粒体DNA合成的电镜放射自显影研究

许多工作表明,线粒体DNA的合成是在整个细胞周期中不断进行的,但在不同生物细胞周期的不同时相中线粒体DNA合成速度高低不同。过去这方面的研究通常都是用动物和低等植物进行的。本文以洋葱根端细胞为材料,用电镜放射自显影法研究了细胞周期各时相的线粒体DNA合成。幻根在~3H-胸腺嘧啶核苷溶液中培养10分钟,水洗5分钟,按常规制备了电镜自显影标本。有丝分裂间期各对相是按核内染色质集缩的形态特点、细胞板形成的进程和核内银粒的多少确定的。按Baserga(1985)报告,Gl期     

用激光在蚕卵上植入染色质引起变异

本文报道一种移植异种基因的新技术，它是用脉冲微束激光照射到置于显微镜下的活细胞，在细胞上造成微孔损伤，异种基因便被植入。我们在“龙角”蚕卵上植入异种染色质溶液，经过培育生长，出现了按预期目的特定变化的当代变异体。并对激光与细胞的作用进行了初步分析。     

Electromigration lifetimes and void growth at low cumulative failure probability

We have investigated electromigration (EM) lifetimes and void formation at cumulative failure probability of around 50 ppm. We carried out EM test in damascene Cu lines using sudden-death test structures. Cumulative failure probability of the test ranges from 50 ppm to 90%. To investigate the void nucleation and growth behaviour, Cu microstructures were investigated by using scanning transmission electron microscopy (S-TEM) and electron backscatter diffraction (EBSD) technique. EM lifetime shows strong correlation with the void nucleation site and the void volume. In addition, the worst case for EM lifetime is that wide angle grain boundary exists just under the via as a void nucleation site.     

可溯源电镜图像管理与检索信息系统的研究与应用

针对电镜分析测试工作中存在的实验信息、样品资料和电镜图像间相互割裂,用户不能便捷地获取实验结果图像和难以进行溯源监管等问题,研发了可溯源电镜图像管理与检索信息系统,实现了实验信息、样品资料和电镜图像的一体化管理和电镜图像即时传递,采用以“图搜图”的反向图片搜索算法,实现电镜图像的可溯源管理.     

Microanalysis and electromigration reliability performance of high current transmission line pulse (TLP) stressed copper interconnects

Electrostatic discharge events can degrade the electromigration (EM) reliability of devices. Transmission line pulsing stress analysis is used to evaluate electrostatic discharge robustness of copper (Cu) interconnects and the impact to EM performance. Compelling evidence from transmission electron microscope data suggests the change in the microstructure of the interconnects explains the creation of latent EM failures.     

Electron microscopy characterization of airborne micro- and nanoparticulate matter

The aim of this work was to offer a state-of-the-art critical survey for characterizing airborne nano- and microparticles by means of electron microscopy (EM) techniques and to highlight advantages and limits of different possible operation modes. Procedures of collection and sample preparation are revisited and improved to analyse airborne particles deposited on filtering membranes by using various sampling methods. Three kinds of electron microscopes are used to this end: scanning electron microscope (SEM), field emission scanning electron microscope (FE-SEM) and transmission electron microscope (TEM). Following and extending previous studies, we optimized procedures by varying both the sample collection/preparation and the operational parameters of the microscopes. In particular, we diversified the sampling methods applied, using ad hoc filters as well as common filters for standard gravimetric measures. This approach enabled us to achieve a simple and clean procedure allowing direct SEM or TEM observation of the collected particulate matter.     

高端电子显微镜实验室环境设计与建设技术要点

电子显微镜(以下简称电镜)是具有超高分辨率的高精密电子光学仪器,广泛应用于科研、工业、医疗、食品安全和生命健康等众多领域,已成为现代物质形态与微结构的重要测试表征与科学研究仪器.近年来,随着球差/色差校正技术、各类原位电镜技术等的快速发展与应用,原子尺度(静态与动态)微结构图像的获取已不再遥不可及.冷冻电镜的发展与普及...     

Electromigration in width transition copper interconnect

Electromigration (EM) experiments are conducted for submicron dual damascene copper interconnects with width transition. The direction of electron flow (from narrow-to-wide segment and wide-to-narrow segment) and the ratio of lengths (e.g. ratio of narrow-to-wide segment lengths) are found to be significant factors in determining the life-time of such interconnects. About 69% shorter EM life-time is obtained for the case of electron flow from narrow-to-wide segment, and thus to avoid over estimation of EM life-time of such interconnect system, the direction of the electron flow should be chosen appropriately in the reliability assessment. On the other hand, it is found that the width transition location is not the failure site, and finite element model is presented to explain the experimental findings.     

Electromigration and Thermomechanical Fatigue Behavior of Sn0.3Ag0.7Cu Solder Joints

The anisotropy of Sn crystal structures greatly affects the electromigration (EM) and thermomechanical fatigue (TMF) of solder joints. The size of solder joint shrinkage in electronic systems further makes EM and TMF an inseparably coupled issue. To obtain a better understanding of failure under combined moderately high (2000 A/cm²) current density and 10–150°C/1 h thermal cycling, analysis of separate, sequential, and concurrent EM and thermal cycling (TC) was imposed on single shear lap joints, and the microstructure and crystal orientations were incrementally characterized using electron backscatter diffraction (EBSD) mapping. First, it was determined that EM did not significantly change the crystal orientation, but the formation of Cu₆Sn₅ depended on the crystal orientation, and this degraded subsequent TMF behavior. Secondly, TC causes changes in crystal orientation. Concurrent EM and TC led to significant changes in crystal orientation by discontinuous recrystallization, which is facilitated by Cu₆Sn₅ particle formation. The newly formed Cu₆Sn₅ often showed its c-axis close to the direction of electron flow.     

Mechanism of pre-annealing effect on electromigration immunity of Al–Cu line

In this work, we have investigated effects of pre-annealing, which means annealing performed prior to electromigration (EM) test, on EM lifetime of Al–Cu lines. We also investigated the relationships between void formation and size of Cu precipitated area in the line under various pre-annealing conditions. It is found that EM lifetime decreases while the size of the Cu precipitated area increases with lengthening of the pre-annealing period. However, no void is observed after this pre-annealing treatment. The results indicate that the tiny voids generated by formation of Cu precipitation do not move during the pre-annealing period. In the case of EM testing, Cu precipitation occurs followed by void formation at the cathode area, probably due to diffusion of vacancies which are generated by Cu atom movement by electron wind. As a result, resistance of the line increases and eventually it fails completely.It is demonstrated that pre-annealing helps Cu atoms to accumulate at the grain boundary forming the Cu precipitates. However, in samples with no pre-annealing treatment, the accumulation of Cu atoms at the grain boundaries begins just after the start of the EM testing and then the Cu precipitates diffuse toward the anode. Since EM test conditions are the same for samples with and without pre-annealing treatment, the only variation is the incubation time to accumulate Cu atoms at the grain boundaries. This is the reason why EM lifetime of pre-annealed samples is shorter than that of samples with no pre-annealing treatment.     

肺黏膜相关淋巴组织型淋巴瘤的免疫组织化学和电镜观察

探讨肺黏膜相关淋巴组织型淋巴瘤（MALTLoma）的免疫表型和超微结构特点，对3例经开胸肺活检病理诊断的肺MALTLoma进行光镜和透射电镜观察以及免疫组化染色。光镜观察发现，瘤细胞主要由中心细胞样淋巴细胞、小淋巴细胞样瘤细胞组成；3例均有淋巴上皮性损伤和反应性淋巴滤泡以及淋巴滤泡的克隆化。免疫组化显示瘤细胞表达B细胞相关抗原。透射电镜观察发现，在支气管黏膜上皮和肺泡上皮细胞周围以及肺泡腔内有较多的淋巴细胞源性瘤细胞浸润，瘤细胞具有淋巴细胞的超微结构特点。对肺MALToma的超微结构观察为该瘤的研究提供了形态学依据，电镜观察对判断瘤细胞的来源和免疫表型有帮助。     

基于EM算法的宽带信号DOA估计及盲分离

本文提出了一种基于EM算法的宽带信号DOA估计与盲分离方法.首先将宽带混合信号转换到频域,然后综合利用带宽内所有频点信息建立似然函数,在此基础上推导出宽带条件下的EM迭代式,从而实现宽带信号DOA及波形的联合估计.并且本文通过分析EM算法的收敛性,自适应的设定角度搜索空间,提高了算法的运算效率.与传统方法相比,本文方法运用的有效信息更多,因此,其在DOA估计精度及波形恢复性能方面都更有优势.仿真实验表明了该算法的有效性.