适用于扫描电镜的拟南芥蜡质样品制备方法

扫描电镜是观察植物表皮蜡质结构的极佳方法。由于蜡质成分不同,不同的植物有不同的样品干燥方法。本文以拟南芥叶片为实验材料,比较FAA固定和戊二醛－锇酸双固定,CO2临界点干燥和冷冻干燥,以及乙醇、乙酸异戊酯、丙酮和叔丁醇等不同的固定方法、不同的干燥方法和不同的有机溶剂对蜡质的溶解作用后,认为更适于拟南芥表皮蜡质观察的样品制备方法是：戊二醛－锇酸双固定,叔丁醇与乙醇梯度脱水,叔丁醇冷冻干燥。     

柑桔寄生线虫扫描电镜制样技术比较研究

应用组织导电法(MPA和CLPG导电液)、环氧树脂包埋法、空气干燥法、CO2临界点干燥法(选用不同的固定剂和脱水剂)等六种方法制样，对云南省柑桔寄生线虫：半穿刺线虫(图1)、短体线虫(图2)、螺旋线虫(图3)进行扫描电镜观察，经过比较，认为用戊二醛-锇酸双固定、酒精梯度脱水、CO2临界点干燥法制样效果优于其它方法：虫体表面环纹、侧线、阴门、肛门、交合刺等明显易见，清晰度好。     

草履虫的扫描电镜观察

草履虫是原生动物门纤毛虫纲的代表动物。它对于细胞遗传和癌症的诊断有重要价值。用DMSO冷冻割断法和扫描电镜制样技术对草履虫进行处理和观察,能获得体表和体内微细结构的三维图象,提供一些新的信息。材料与方法:稻草浸液培养草履虫,2％lugol′s液缓慢地杀死,2.5％戊二醛和锇酸双固定,乙醇逐级脱水,乙酸异戊酯置换,CO_2临介点干燥,高真空浅射黄金,扫描电镜观察。断面样品用DMSO冷冻割断法。     

适合光镜和电镜诊断肾小球疾病的固定剂选择

目的：为了使已经石蜡包埋的肾穿组织脱蜡后进行电镜观察,关键是选择适当的固定剂。方法：在石蜡包埋前,肾穿组织分别用甲醛、戊二醛及戊二醛、锇酸双固定。根据光镜和电镜观察结果,选择能兼顾光镜和电镜的固定剂。结果：甲醛固定不能有效保存肾穿组织的超微结构,锇酸的固定能有效地保存超微结构,但严重影响了光镜切片的染色;而戊二醛与甲醛相比,较好地保存了肾穿组织的超微结构,同时又不影响光镜切片的染色。结论：在石蜡包     

扫描电镜观察不同抗凝剂对血细胞形态的影响

电子显微镜观察血液细胞的形态及超微结构的报导很多,但采血时所用的抗凝剂及制样固定时的温度对血细胞形态的影响却报导至少。本实验主要以扫描电镜观察肝素、枸橼酸钠、草酸钾三种常用抗凝剂对血细胞形态的影响。实验方法;取健康狗静脉血,分别注入三种抗凝及生理盐水管摇匀待用。红细胞制备:分别取上述四种血样用二甲胂酸钠缓冲液(pH7.4)洗涤后,滴到有Formvar膜的盖玻片上,静置数分钟,吸去上清液,戊二醛及锇酸双固定,以下按常规脱水、置换、临界点干燥,喷镀、镜检。生理盐水作为对照。     

一种适用于蚊类扫描电镜样品简便快速的制备方法

本文介绍一种适合蚊类研究的扫描电镜样品制备方法.以库蚊为样品,用四氧化锇直接单固定处理,适当缩短脱水时间,改进临界点干燥前的制样程序.此方法观察效果良好,提高了样品制备质量,为蚊类扫描电镜样品制备提供了一种简易而快速的方法.     

人早幼粒白血病细胞(HL—60)的表面超微结构及其在诱导分化过程中的变化

为了解HL—60细胞的表面形态特征以及它们在诱导分化过程中的变化,我们应用扫描电镜技术,结合超薄切片和组织化学方法,对HL—60细胞的表面形态进行了观察分析。 HL—60细胞常规培养,部分细胞以终浓度为10~(-6)M的维生素A酸处理。在指定时间内,收集对照组与给药组的HL—60细胞,2.5％戊二醛固定。经锇酸—单宁酸—锇酸处理后,梯度乙醇脱水,CO_2临界点干燥,真空喷金。在日立S—450扫描电镜下观察。透射电镜标本制备和糖原的组织化学反应(PAS)按常规进行。扫描电镜下,HL—60细胞最明显的表面形态特征是绝大多数细胞(约占90％)具有丝状伪足。这种丝状伪足     

含水生物样品的环境扫描电镜观察

目前，在常规的扫描电镜中观察含水的生物样品有两种方法：（１）用戊二醛和锇酸固定细胞的骨架，再用乙醇脱水，二氧化碳临界点干燥后喷金，然后放入扫描电镜观察。（２）样品深度冷冻后使用冷冻样品台放入扫描电镜观察。以上两种制备方法都会使样品失去原来的自然面貌。...     

豚鼠半乳糖性白内障晶体的扫描电镜观察

200g左右成年豚鼠17头分成对照及模型二组。模型组用25％d一半乳糖125mg/kg作球后注射,每天一次,连续34天。在第10天后作裂隙灯检查,晶体发现有空泡,20天后有晶体周边空泡及混浊,第34天摘眼球每鼠取1晶体作扫描电镜观察。制样方法:将晶体放入4％戊二醛磷酸缓冲液(1/15M,pH7.3)数日,1％锇酸后固定,丙酮梯度脱水,临界点干燥,沿前后轴断裂样品。     

心肌纤维的ODO高分辨扫描电镜观察

本文采用ODO高分辨扫描样品制备技术,观察了小白鼠、大白鼠和犬心肌纤维表面及断面的微细结构,并讨论了高分辨扫描电镜观察法的技术特点,分析了心肌纤维的超微结构及其与功能之间的关系。技术方法按常规取材、将样品修成梭形,放入1％锇酸中固定1～2小时;继以1/15M磷酸缓冲液清洗,用25％、50％的二甲基亚砜分别浸泡20分钟,并在TF-2型冷冻割断台上将样品割断;尔后,用1％锇酸对样品作后固定,0.1％锇酸软化细胞基质,再以1～2％单宁酸对样品作导电处理,用1％锇酸对样品进行终末固定;最后,对其进行脱水、干燥、镀膜处理后,用扫描电镜观察。     

高压冷冻-冷冻替代技术在神经组织超微结构中的应用

采用高压冷冻-冷冻替代技术对小鼠和线虫这两种模式生物的神经组织进行了样品制备、超薄切片和电镜观察,并在取材方式上进行了摸索,旨在比较化学固定法(CF)、高压冷冻固定法(HPF)和化学-高压冷冻联合固定法(CF+ HPF)三种不同方式对神经组织超微结构的影响,促进高压冷冻-冷冻替代技术在神经生物学中的应用.透射电镜观察结果显示:与传统的化学固定相比,高压冷冻固定对神经组织样品具有较好的优势,能够减少化学处理所产生的人工假象;另一方面,对于不同动物的神经组织而言,所适用的固定方式也不相同,鼠脑适用于活检枪(biopsy gun)取样后直接进行HPF固定,所得结构比较完整,神经组织微观结构清晰.而在高压冷冻之前选用CF进行预固定,能加大样品结构保存的完整性,但在膜的细腻程度上不如直接进行高压冷冻制样的结果.线虫样品由于存在较厚的体壁保护,它更适于直接进行HPF处理,从而缩短了固定前的滞留时间,可有效保留腹部神经元超微结构.     

A useful method for observing intracellular structures of free and cultured cells by scanning electron microscopy

Scanning electron microscopy (SEM) using osmium-maceration methods has been used for analyzing the three-dimensional structure of cell organelles in tissue samples, but it has been quite difficult to observe free and cultured cells with this technique. The present study was performed to develop a method that can be applied to free and cultured cells for SEM studies of intracellular structures after osmium maceration. The method was also applied to light microscopy (LM) and to transmission electron microscopy (TEM). HeLa cells and human leukocytes were fixed with a mixture of 0.5% paraformaldehyde and 0.5% glutaraldehyde followed by an additional fixation with 1% osmium tetroxide. These cells were embedded in low-melting-point agarose. A temperature-responsive dish was also used for collection of cultured cells before embedding. For LM and TEM, the cell-embedded agarose was further embedded in epoxy resin, and semi- and ultrathin sections were examined conventionally. For SEM, the agarose was freeze-fractured in 50% dimethyl sulfoxide, processed for osmium maceration and observed in a high-resolution SEM. Low-melting-point agarose was useful as an embedding medium for SEM, because it was well preserved during prolonged osmication for SEM. Thus, the fine structure of cell organelles was clearly analyzed by SEM after osmium-maceration treatment. These SEM images could also be compared with those of LM and TEM of the agarose-embedded tissues.     

二种固定方法对扫描电镜用植物细胞冷冻割断样品的影响

本文用冷冻割断法在扫描电镜下观察了大蒜(Allium sativum L.)根尖分生组织细胞内部的三维结构。样品制备采用了两种固定方法:冷冻割断前只用1％的锇酸固定的材料易在细胞质和细胞核之间断开;而先用Bouin‘s液固定,再用1％锇酸固定的材料易使细胞核被断开。据此认为前一固定法适于研究细胞质的内部结构(如细胞骨架纤维、线粒体、内质网等)及其三维分布关系;后一种固定法适于核内结构(染色质、核仁、核基质纤维)的三维图象的研究,特别是核仁纤维中心染色质的三维结构。     

A novel accelerated test technique for assessment of mechanical reliability of solder interconnects

New generations of lead-free solder interconnects are widely used in consumer electronics. Reliability of the devices which are subjected to rough handling, depends on the fracture resistance of the solder interconnects to shock and mechanical loading. The conventional reliability testing procedures are reported to be expensive and time consuming. Thus alternative tests and evaluation methods for reliability assessment of solder joints are required. In this study a new method for quality assessment of solder interconnects under high strain vibrational shear loading is presented using an ultrasonic fatigue testing system in combination with a special experimental set-up. Using this technique lifetime curves for solder ball bonds of two different Sn–Ag–Cu lead-free alloys were obtained. Failure mechanisms of the solder ball bonds were studied using SEM methods and the reliability curves were discussed with regard to the failure modes and the composition of the lead-free alloys. The applicability of the proposed method is discussed with regard to the literature data.     

Electron channelling contrast imaging for III-nitride thin film structures

Electron channelling contrast imaging (ECCI) performed in a scanning electron microscope (SEM) is a rapid and non-destructive structural characterisation technique for imaging, identifying and quantifying extended defects in crystalline materials. In this review, we will demonstrate the application of ECCI to the characterisation of III-nitride semiconductor thin films grown on different substrates and with different crystal orientations. We will briefly describe the history and the theory behind electron channelling and the experimental setup and conditions required to perform ECCI. We will discuss the advantages of using ECCI, especially in combination with other SEM based techniques, such as cathodoluminescence imaging. The challenges in using ECCI are also briefly discussed.     

Reprint of: Electron channelling contrast imaging for III-nitride thin film structures

Electron channelling contrast imaging (ECCI) performed in a scanning electron microscope (SEM) is a rapid and non-destructive structural characterisation technique for imaging, identifying and quantifying extended defects in crystalline materials. In this review, we will demonstrate the application of ECCI to the characterisation of III-nitride semiconductor thin films grown on different substrates and with different crystal orientations. We will briefly describe the history and the theory behind electron channelling and the experimental setup and conditions required to perform ECCI. We will discuss the advantages of using ECCI, especially in combination with other SEM based techniques, such as cathodoluminescence imaging. The challenges in using ECCI are also briefly discussed.     

Application of the environmental SEM in human dentin bleached with hydrogen peroxide in vitro.

The environmental SEM (E-SEM) can be used unfixed biological samples under a low vacuum and wet condition. In this study, the fractured dentin of unfixed human teeth was treated with a 30% hydrogen peroxide solution (H2O2) for the examination of tooth-bleaching prior to the E-SEM and a conventional SEM. The peritubular matrix (PM) always showed a few cracks along the long axis of a dentinal tubule, and the ends of fine fibrils rose to the smoothly changed surface of the intertubular matrix (IM). The E-SEM with non-fixation and the conventional SEM following fixation indicated that the hydrogen peroxide solution easily permeated the PM and dissolved the non-fibrillar substance including the cracks of the PM by the constriction. In the IM, the solution may partially dissolve the organic parts within mineralized fibrils as well as non-fibrillar substance between the fibrils, although these remnants might precipitate again there.     

A Hybrid SIM-SEM Method for 3-D Electromagnetic Scattering Problems

A new method combining the spectral integral method and spectral element method (SIM-SEM) is proposed to simulate 3-D electromagnetic scattering from inhomogeneous objects. In this hybrid technique (a special case of the finite element boundary integral (FEM-BI) combination), the SEM with the mixed-order curl conforming vector Gauss-Lobatto-Legendre (GLL) basis functions are used to represent the interior electric field with high accuracy, while the SIM on a cuboid surface is used as an exact radiation boundary condition. The Toeplitz property of the SIM matrix is utilized to reduce the memory and CPU time costs in an iterative solver by using the fast Fourier transform algorithm. Unlike the traditional FEM-BI combination where the BI portion usually dominates the computational complexity, the computational costs are much lower in the SIM-SEM method. Numerical results verify the accuracy and capability of this method, confirming that the SIM-SEM method is a good alternative for solving scattering problems from inhomogeneous objects.