摘要:

AbstractA controlled atmosphere specimen holder (CASH) has been developed for transmission electron microscopy (TEM) experiments. It is designed for studying the specimen's microstructure before and after treatments in various gases (H2, O2, N2, Ar, etc.) at temperatures up to 600°C. The experiments are carried out without exposing the specimen to the ambient atmosphere. No modification of the electron microscope itself is needed. The same area of the specimen can be easily located after each gas treatment, thus the changes in the microstructure can be studied directly. Preliminary results on the cyclic oxidation and reduction of a model cobalt catalyst are presented

ISSN:0741-0581    

DOI:10.1002/jemt.1060020602

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractReflection electron microscopy (REM) is shown to be applicable to the testing of the quality of AlxGa1−xAs/GaAs layer structures. Cross‐sectional images of quantum well structures with layer thickness down to 1 nm can be obtained. The practical aspects of the REM technique are presented. The most important advantages and drawbacks of cross‐sectional REM are discussed in d

ISSN:0741-0581    

DOI:10.1002/jemt.1060020603

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractAspiration biopsy of tumors and transplanted organs is a popular atraumatic method for diagnosis and also for the management of patients. Apart from the cytological analyses, it is clear that large aggregates of cells are obtained and these may be examined by electron microscopy. A study was carried out with dogs to assess the yield of intact glomeruli and tubules, resulting from a standard fine‐needle aspiration procedure. Employing a 20‐gauge needle, yields of approximately ten intact glomeruli were obtained with a tissue processing protocol that utilized filtration through a nylon mesh and backwashing, to resuspend the trapped aggregates. Processing for electron microscopy was carried out in microcentrifuge tubes. The ultrastructural preservation was excellent and the extension of these studies to investigations of not only renal transplantation, but also for diagnosis in human renal diseases of a broad spectrum, is sugges

ISSN:0741-0581    

DOI:10.1002/jemt.1060020604

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractThe effects of epoxy resin formulation on tissue contrast and organelle size were evaluated by examining thin sections of rat liver in the electron microscope and by doing a simple morphometric analysis of peroxisome and nuclear size. Contrast was greatest for tissues embedded in the Quetol formulation of Kushida and least for tissues embedded in the Ladd formulation. Epon 812, Epon‐Araldite, and Spurr formulations gave results intermediate to those of the Quetol and Ladd formulations. Organelle size was greatest for tissues embedded in the Ladd formulation and smallest for tissues embedded in the Spurr formulation. The maximum size differences were approximately 15%. Epon 812, Epon‐Araldite, and Quetol formulations gave results (for organelle size) intermediate to those of the Ladd and Spurr formulations. The gross shrinkage properties of the epoxy resin blocks were all the same and, therefore, could not account for the differences in organelle s

ISSN:0741-0581    

DOI:10.1002/jemt.1060020605

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractElectron‐dense arsenic inclusions appeared in the nucleus of parenchymal hepatocytes from fish exposed to arsenate, but were absent in fish exposed under identical conditions to solutions lacking arsenic. Images of these inclusions were compared using conventional transmission electron microscopy (CTEM), scanning transmission electron microscopy (STEM), and high‐voltage electron microscopy (HVEM). Stereo pairs from the same individual inclusions were examined using each of these methods to provide a more complete understanding of their three‐dimensional organization and to evaluate the relative merits of each technique in the study of similar electron‐dense structures.Comparable results were obtained with the three types of instrumentation. Although HVEM is the technique of choice for the analysis of three‐dimensional images of such high electron‐dense structures, STEM proved to be a good alternate technique for the selection and general evaluation of samples in preparati

ISSN:0741-0581    

DOI:10.1002/jemt.1060020606

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractThe immunoelectron microscopy preembedding method using peroxidase‐labeled antibodies has enabled us to localize various bioactive substances in subcellular organelles, i.e., nucleus, cytosol, perinuclear space, rough endoplasmic reticulum, Golgi complex, secretory granules, mitochondria, etc. In this text, detailed procedures and some key points for the appropriate staining are described. The applications of this technique to localize substances in various organelles and to observe ultrastructural changes of intracellular hormones are also discusse

ISSN:0741-0581    

DOI:10.1002/jemt.1060020607

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractCross‐sectional transmission electron microscopy (XTEM) is an imaging technique particularly suited to the study of layered structures. For integrated electronic devices it has become a common practice to use XTEM to assess the shape and crystallinity of component layers as well as defect structures introduced by processing. A procedure for preparing samples to be viewed by XTEM is describe

ISSN:0741-0581    

DOI:10.1002/jemt.1060020608

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractA method for bacterial identification has been developed by means of studying the same histological sections through several types of microscopy. With this method, one section was processed and analyzed respectively for light microscopy (LM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Sections of gingival biopsies were Gram stained and bacteria tentatively identified by LM. Photographs of the sections were taken and presketched transparent acetate sheets (PTAS) were made from the photos. The same section was later prepared for SEM, areas previously thought to contain bacteria were localized by placing the PTAS onto the SEM monitoring screen. The SEM specimens were subsequently processed for TEM, bacteria were located, and micrographs obtained. The results showed that out of ten diseased gingival biopsies observed under the LM, bacteria were found to be present in all the specimens and were identified as both Gram positive and Gram negative. By transferring the section from LM to SEM, the bacteria could be relocated and their morphotype (cocci, rods, etc.) clearly identified in most of the cases. Since cocci may resemble other biological granular structures under SEM, they require further analysis under TEM for additional positive identification. This study demonstrated that the method described here is a useful tool for assessing the presence and identifying bacteria within the gingival tissues.

ISSN:0741-0581    

DOI:10.1002/jemt.1060020609

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractA method is proposed to enhance contrast between microdomains of two‐component polymer systems using electron beam radiation damage. The technique is based on the different damage patterns to crosslinking‐type and scission‐type polymer particles embedded in ice. Whereas the former lose little mass and cavities form in the ice around them, the latter lose much more mass, become cellular in appearance, and occasionally swell. Applications of the technique are demonstrated by revealing the microstructure of two‐stage poly(butylacrylate)/polystyrene latices, their size distributions, and the presence of single‐component particles in the two‐compo

ISSN:0741-0581    

DOI:10.1002/jemt.1060020610

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractCurrently, quantitative studies of malignant lymphoma are being performed in an attempt to improve the classification of non‐Hodgkin's lymphoma (NHL) for diagnostic, prognostic, and therapeutic purposes. Morphometric image analysis is one method that can be employed in cases of NHL to obtain objective data of nuclear parameters; condensed chromatin being a compartment of the nucleus best measured at the ultrastructural level. This report assesses similarities or differences in the amount, distribution, and arrangement of condensed chromatin in nuclear profiles of normal and neoplastic lymphocytes in human surgical biopsy specimens. Morphometric data derived from electron micrographs of lymphocytes in germinal centers of lymph nodes with reactive hyperplasia (three cases) and small cell types of NHL two examples of malignant lymphoma, well differentiated lymphocytic type (ML, WDL) and three cases of malignant lymphoma, poorly differentiated lymphocytic type (ML, PDL) are compared. Results indicate that the distribution of condensed chromatin, i.e., the size of aggregates, and their spatial placement within the nucleus varies more than the amount (both mean area per profile or mean volume) of this nuclear parameter, and that this applies to normal as well as neoplastic lymphocytes. When a series of condensed chromatin parameters were statistically compared, no major differences could be detected between lymphocytes in normal tissues and those in ML, WDL and ML, PDL, but considerable differences were found in each of the nuclear morphotypes in the individual cases within the groups. This degree of variation in nuclear characteristics within normal tissues and the two lymphoma categories has not been previously recognized. Clearly, the technique of morphometric analysis, as applied to electron micrographs, can provide new and useful data that must be appreciated if classification schemes currently used in NHL are to improve and reflect biologic consideration

ISSN:0741-0581    

DOI:10.1002/jemt.1060020611

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY