水稻花粉白苗原质体的超微形态观察

通过透射电镜观察了水稻花药培育产生的白苗、再分化白苗及绿苗,发现花粉绿苗的叶绿体和水稻正常植株的叶绿体在超微形态上是相同的。但是在花粉白苗质体观察中未发现能发育成正常叶绿体的质体中心及发育完好的基粒片层和基质片层。在观察中还发现花粉白苗原质体形成有增殖分裂和直接形成两种方式,但不论哪种方式其初始原质体都具有内、外二层被膜(而每层又都是双层的。)内膜内有大量的核糖核蛋白体。当原质体继续发育时内     

大豆子叶细胞中变形质体的形成和发育过程

质体是植物细胞中特有的一种细胞器。原质体、白色体、叶绿体和有色体之间的发育有着密切的关系。变形质体是一类不规则形状的原质体,多呈哑铃形、马蹄形或杯状。前人曾在许多植物的多种组织中看到过变形质体。但是关于变形质体的作用和进一步发育趋势目前尚无一致的看法。本文采用常规透射电镜技术观察了大豆子叶细胞中变形质体的形成和发育途径。结果和讨论:开花后19天的大豆子叶细胞中有许多原质体。其中部分原质体呈圆球形(图1)。部分原质体呈哑铃形(图2)、马蹄形(图3)和环形。从三维空间进行分析,马蹄形质体是杯状质体的一个     

患者增殖体、扁桃体组织内尼曼-匹克细胞的超微结构观察

目的：观察尼曼-匹克病患者增殖体、扁桃体组织中的尼曼-克细胞的超微结构。方法：取增殖体、扁桃体组织做超薄切片,透射电镜下观察尼曼-匹克细胞的超微结构。结果：在透射电镜下,尼曼-匹克细胞呈圆形或椭圆形,细胞质丰富,其中有数量不等的嗜锇板层小体,呈板层状或同心圆状排列。细胞基底部,可查见单层或多层基底膜和细胞表膜下有少数吞饮小泡,具有内皮细胞形态特征。结论：尼曼-匹克细胞的细胞质内可见数量不等的嗜锇板层小体及基底部的单层或多层基底膜,为其特征性的结构,可作为电镜超微结构诊断及鉴别诊断的形态学依据。     

霉形体在原代细胞内增殖的观察

霉形体在原代细胞内增殖的观察杨盛华，宁宜宝，邹啸环，常国权，刘维全（农牧大学军事兽医研究所，长春１３００１２）对接种霉形体的原代细胞进行了电镜观察。结果如下：（１）进入细胞内的霉形体，不仅能以包涵体形式存在，也可以散在形式分布，同时还能进入粗面内质网...     

骨髓瘤瘤细胞的超微形态研究

本文报道了8例骨髓瘤(包括5例多发性骨髓瘤,3例轻链病)瘤细胞的超微形态改变。所见各例瘤细胞的分化程度不同,电镜下瘤细胞的形态变化较大,分化较好的瘤细胞,形态接近正常浆细胞,分化越差,异常形态特征明显。8例标本中,一例有大量核内包涵体(图1),3例有Russell小体(图2),其中一例的Russell小体特别丰富。另一例中,见到结晶体(图3)具有周期性排列的线条结构。此外,在4例骨髓瘤细胞中见到微丝,其中二例尤为显著。本文对骨髓瘤细胞在电镜下主要超微形态改变,以及核内包涵体,胞浆包涵体、胞浆微丝的     

黄金树核内包涵体的研究

应用透射电镜技术研究了黄金体叶芽和根尖细胞中的核内包涵体。观察发现在薄壁组织、保护组织及输导组织的细胞中，都普遍存在核内包涵体。刚分裂后的幼小细胞中的核内包涵体为纤丝状结构，而在成熟的细胞中则主要是大块的片层状结构。我们对梓树属植物的研究证明，核内包涵体有稳定的超微结构特征。在分生组织中，处于有丝分裂前期和中期的细胞中未找到包涵体。而在有丝分裂末期，观察到了纤丝状核内包涵体。本文认为这类包涵体起源     

大豆种子萌发过程中子叶细胞超微结构和ATP酶活性动态研究

采用磷酸铅沉淀的电镜细胞化学方法，研究大豆种子萌发过程中，子叶细胞超微结构变化与ATP酶活性的消长。子叶细胞的ATP酶活性主要定位在质膜。在种子萌发的0-3天，子叶细胞贮存蛋白质和油脂大量急剧降解，并快速转运到胚，质膜ATP酶活性较高。萌发的6-9天，子叶细胞内含物大部分消解，蛋白体膜相互融合形成大液泡，原质体开始有稀疏的片层结构，ATP酶活性渐弱至无。萌发第12天，原质体的片层堆叠成基粒，子叶细胞转为同化器官，制造养分，质膜再度呈现较强的ATP酶活性。子叶细胞质膜ATP酶活性反应子叶细胞生理代谢状态。     

支原体感染的不育症精子扫描、冷冻复型观察

男性不育症患者精液及从精液中分离培养的解脲支原体,加磷酸缓冲液多次离心纯化后用2.5％戊二醛固定,再离心备用,作扫描电镜观察的样品:取沉淀物滴于铜片上、脱水、临介点干燥、镀金,用H—3010及Amray 1000B扫描电镜观察;作冷冻复型的样品经3％甘油处理后在BAF400D冷冻复型仪中制成复型膜,用H—300及JEM1200EX电镜观察。结果:1.解脲支原体(图3):解脲支原体是能独立生长的最小微生物,缺乏细胞壁,只有一层细胞膜(由暗-明-暗3层组成),最适生活环境为pH7.5,厌氧环境生长更好;形态为多形性的,有球形、杆形、哑铃形,有的部分膨大、分枝成星形或螺旋形,偶见链状或丝状,大小差别很大,从80-800nm不等,分裂繁殖或分枝断裂繁殖。     

灰茶尺蛾核型多角体病毒形态发生的超微结构

灰茶尺蛾(Ectropis grisescens W)是我国中南地区茶树的主要害虫。灰茶尺蛾核型多角体病毒可以使该幼虫致死。该病毒为单粒包埋型的昆虫杆状病毒。作者曾对多粒包埋型的斜纹夜蛾核型多角体病毒等在体内的形态发生和装配过程作过详细的报告。近两年来,我们应用电子显微技术,对该种新发现的灰茶尺蛾核型多角体病毒,在幼虫体内形态发生过程中的丝状纤维和核糖体等的超微结构进行了观察和分析。     

木薯块根膨大初期淀粉体形态及发育的扫描电镜观察

对华南木薯3个品种（SC124、SC8、Arg7）膨大初期的木薯块根淀粉体的大小、形态、分布排列和发育等特性进行了扫描电镜观察。结果表明：淀粉主要沉积在木薯块根的次生韧皮部和木质部的薄壁细胞中。木薯块根淀粉体形态品种间没有明显差异,主要为球形,常见有椭球体、不规则的半球体、多极球体等形态,但淀粉体大小及空间排列在3个品种间差异显著。SC124淀粉体平均直径最小,淀粉体的变异系数大,淀粉体间空隙较大,呈层状排布;SC8淀粉体大小较为一致,变异系数小,淀粉体排列紧密,呈束状排布;Arg7淀粉体大小及变异系数都较小,淀粉体排列较为疏松,成团状排布。结论：淀粉体的大小、形态、空间排列及增殖方式可能是影响木薯块根淀粉充实程度和品质特性直接原因。     

Development of a Ground-Based Simulated Experimental Platform for Gravitational Biology

The purpose of this study is to develop a ground-based experimental platform which can provide a long-term, persistent, and stable weightless environment to provide technical support for the fundamental study of space life sciences. The platform included a superconducting magnet which can generate a large gradient high magnetic field, temperature control system, object stage, observing system, and gas control system. The platform can accurately measure and control comprehensive parameters, such as temperature, humidity, sample location, gravity level, and magnetic induction intensity. The biological experiment by means of the platform indicated that diamagnetic levitation affected cell morphology but had nonlethal effects on cell growth, which is consistent with the results of spaceflight. It suggests that the platform can meet the need of the simulated experimental conditions for gravitational biology research from molecule, cell, tissue, and organ to model animal.     

Diamagnetic levitation causes changes in the morphology, cytoskeleton, and focal adhesion proteins expression in osteocytes

Diamagnetic levitation technology is a novel simulated weightless technique and has recently been applied in life-science research. We have developed a superconducting magnet platform with large gradient high magnetic field (LG-HMF), which can provide three apparent gravity levels, namely, μg (diamagnetic levitation), 1g, and 2g for diamagnetic materials. In this study, the effects of LG-HMF on the activity, morphology, and cytoskeleton (actin filament, microtubules, and vimentin intermediate filaments) in osteocyte - like cell line MLO-Y4 were detected by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) methods, hematoxylin-eosin (HE) staining, and laser scanning confocal microscopy (LSCM), respectively. The changes induced by LG-HMF in distribution and expression of focal adhesion (FA) proteins, including vinculin, paxillin, and talin in MLO-Y4 were determined by LSCM and Western blotting. The results showed that LG-HMF produced by superconducting magnet had no lethal effects on MLO-Y4. Compared to control, diamagnetic levitation (μg) affected MLO-Y4 morphology, nucleus size, cytoskeleton architecture, and FA proteins distribution and expression. The study indicates that osteocytes are sensitive to altered gravity and FA proteins (vinculin, paxillin, and talin) may be involved in osteocyte mechanosensation. The diamagnetic levitation may be a novel ground-based space-gravity simulator and can be used for biological experiment at cellular level.     

原子力显微镜在生殖支原体研究中的应用

为了确定生殖支原体在活性条件下的结构形貌,并在较高的分辨水平上观察其三维形貌结构,本研究采用原子力显微在常温常压下对生殖支原体标准株及分离株进行形态学的初步观察,将标本固定于云母上,在ｔａｐｐｉｎｇ模式下扫描成像,结果显示：生殖支原体多呈烧瓶状或鸭梨状,有突出的颈产及膨大的头端,与电镜观察结果类似,其大小亦与银镜测量结果类似。     

Controlling radiated emission from a physically largetelecommunication system

This paper deals with the problems that arise when physically large systems, such as a digital switching exchange for high speed broadband applications, must be tested in order to comply with the EN 55022 standard for radiated emission. Simple closed formulas to predict radiated emissions from elementary sources, such as tracks in PCBs, cables, and small apertures, are outlined with their limits of application and verified by measurements. An analysis of the radiation patterns of simple structures and complex systems is also given     

A global spatial similarity optimization scheme to track large numbers of dendritic spines in time-lapse confocal microscopy

Dendritic spines form postsynaptic contact sites in the central nervous system. The rapid and spontaneous morphology changes of spines have been widely observed by neurobiologists. Determining the relationship between dendritic spine morphology change and its functional properties such as memory learning is a fundamental yet challenging problem in neurobiology research. In this paper, we propose a novel algorithm to track the morphology change of multiple spines simultaneously in time-lapse neuronal images based on nonrigid registration and integer programming. We also propose a robust scheme to link disappearing-and-reappearing spines. Performance comparisons with other state-of-the-art cell and spine tracking algorithms, and the ground truth show that our approach is more accurate and robust, and it is capable of tracking a large number of neuronal spines in time-lapse confocal microscopy images.     

The effect of electroplating parameters and substrate material on tin whisker formation

Electroplated tin finishes are widely used in the electronics industry due to their excellent solderability, electrical conductivity and corrosion resistance. However, the spontaneous growth of tin whiskers during service can result in localised electrical shorting or other harmful effects. Until recently, the growth of tin whiskers was successfully mitigated by alloying the tin with lead. However, restriction in the use of lead in electronics as a result of EU legislation (RoHS) has led to renewed interest in finding a successful alternative mitigation strategy.Whisker formation has been investigated for a bright tin electrodeposit to determine whether whisker growth can, at least partially, be mitigated by control of electroplating parameters such as deposition current density and deposit thickness. The influence of substrate material and storage at 55 °C/85% humidity on whisker growth have also been investigated.Whisker growth studies indicate that deposition parameters have a significant effect on both whisker density and whisker morphology. As deposition current density is increased there is a reduction in whisker density and a transition towards the formation of large eruptions rather than potentially more harmful filament whiskers. Increasing the tin coating thickness also results in a reduction in whisker density. Results demonstrate that whisker growth is most prolific from tin deposits on brass, whilst that from tin deposits on rolled silver is greater than that observed for tin deposits on copper.     

Valence band mixing and optical emission in modulation-doped GaAs-(AlGa)As heterostructures

Unexpected optical emission spectra from electrons confined in GaAs quantum layers reveal a strong component with polarization normal to the plane of the layers. For elementary electron-hole recombination processes, this suggests surprisingly large band mixing in the ground valence subband. Effective mass theories that include conventional symmetry breaking mechanisms do not satisfactorily account for this phenomenon. The stress dependence of the spectra confirm that many body shake-up processes in the Fermi sea are important in describing emission associated with the 2D electron plasma.     

On the integration of an internal human conditioning system

Medical equipment is reviewed for its relative importance in sales and for its suitability to be integrated. It is shown how most implantable circuit configurations can be derived from an internal human conditioning system (IHCS), which carries out all elementary functions of measurement and stimulation in the human body. The potential integration of such an IHCS is discussed. For the sake of illustration a number of devices and circuits are presented, such as a low-power VCO, a micropower op amp, a biotelemetry chip, and an ear stimulator decoder chip.     

一种随机Petri网性能等价化简与分析方法

随机Petri网模型是系统性能评价的有力工具,但其状态空间随模型规模的增长而指数性增长的问题限制了其对复杂和大规模系统模型的性能数量分析能力.因此,在对模型进行分析之前,先对其进行适当的性能等价化简,是一种更为可行的分析方法.本文首先讨论了一类随机Petri网-基本随机Petri网(ESPN)的性能等价分析方法,这类随机Petri网由顺序、并行、选择和循环等四种基本结构及其组合构成.作者推导出这四种基本结构的性能等价公式,并运用自底向上逐步综合替代的分层分析方法,给出这类随机Petri网模型的性能等价化简分析方法,该方法的复杂性随模型增长而线性增长,有效解决了其性能数量分析问题.然后,讨论了两种非基本结构到基本结构的转换规则,使得复杂的随机Petri网模型也可能转换为ESPN模型,从而使性能等价算法可应用于一般随机Petri网.