ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1985.tb02553.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

SUMMARYThe expression used in the electron microscopical measurement of dislocation densities is ϱ=2N/Lt, whereNis the number of intersections between the dislocation lines in a TEM image,Lthe total length of a set of sampling lines superimposed upon that image (corrected for magnification) andtthe thickness of the thin foil containing the dislocation structure. During the estimation of ϱ it is therefore important to reduce errors in the measurements of all three variables. It is shown how calibration of the microscope magnification, careful consideration of diffraction conditions and use of the hollow cone and rocking beam facilities on the hybrid diffraction unit fitted to the Philips EM 400T can assist in increasing the speed and accuracy of the measurement procedur

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1985.tb02554.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

SUMMARYA method is described for scanning electron microscope (SEM) autoradiography whereby preservation of high resolution cell surface details is retained together with degelatination of the emulsion without gross loss or redistribution of silver grains. This method should provide a convenient medium‐sized marker for SEM (using secondary, backscattered electron and X‐ray imaging) topographic studies of biosynthesized molecules, and of cell surface receptors and antigens, using indirect or direct labelling procedures with radio‐labelled li

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1985.tb02555.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

SUMMARYA new technique is presented for studying cell membranes by scanning electron microscopy. It is based on the observation that cells and tissues, embedded in a water‐compatible melamine resin, are as hard as glass and consequently can be fractured with ease. Fracture faces so exposed are either sputter‐coated for studying the surface topography or re‐embedded for thin‐sectioning, or both.Scanning electron microscopy shows that the fracture faces of a variety of tissues reveal cell membranes and associated structures with remarkable detail. Re‐embedding and thin‐sectioning of fractured frog retina, mycoplasma and red blood cells indicate that membranes become divided into their exo‐ and protoplasmic leaflets during fracturing. In this respect, the results reported here must be compared with conventional freeze‐frac

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1985.tb02556.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

SUMMARYUsing a simple and fast technique, chromosomes and nuclei of V. faba were isolated and examined under various magnifications with SEM. Details of chromatin construction were observed.

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1985.tb02557.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

SUMMARYA method is described which permits the observation of microscopic specimens in both top and side views, a rapid change between the two views being possible without disturbing the specimen. The system requires the introduction of simple optical components into a culture chamber, does not restrict the types of microscopy that may be used, and does not necessitate modification of the microscope itself. The technique is discussed in relation to the study of tissue cells in culture, but may find applications in other areas.

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1985.tb02558.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

SUMMARYThe use of high molecular weight polyethylene glycol as an embedding medium for the production of resin‐free sections of plant cells is described. Specimens can be observed at a range of accelerating voltages, are high in contrast and require no heavy metal staining. All the major organelles appear intact and a three‐dimensional network of filaments in the cytoplasm and nucleoplasm is repor

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1985.tb02559.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

SUMMARYThree micrographs made at different tilting angles are necessary to determine the spatial coordinates of each point from the surface of micro‐object. The x′ and y′ coordinates of the points are measured in an arbitrary coordinate system O'X′Y′ which ensures convenience in measurements. The coordinates measured are transformed into a main coordinate system OXYZ related to the microscope and the image plane. The z coordinates are calculated. The coordinates of the points are used to solve the following metric problems by applying analytical geometry: computation of (1) distances (between: two points, a point and a straight line, a point and a plane), (2) angles (between: two straight lines, a straight line and a plane, two planes), (3) area of a triangle and (4) volume of a body, which may devided into tetrahedra. A computer program for solving the above problems is written

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1985.tb02560.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

SUMMARYA modification of the glutaraldehyde‐osmium tetroxide‐tannic acid‐uranyl acetate (GOTU) fixation procedure is described which allows human leucocytes to be examined subsequently by either transmission electron microscopy (TEM) or scanning electron microscopy

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1985.tb02561.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

SUMMARYMeasurement of the width of a thin, cylindrical, transparent object by phase contrast light microscopy has been frustrated by the absence of an established relationship between the true width of the object and its apparent width in the phase contrast image. We have solved this problem by devising a simple method by which individual glass fibres may be measured using both phase contrast light microscopy and electron microscopy. Using this method we have constructed calibration curves relating the diameter measured by phase contrast microscopy to the real diameter of the fibres. These curves are linear in the range 0.10‐2.5 μm real diameter, with slopes close to unity and intercepts of about 0.2 μm. Thus widths of such objects are overestimated. The precise value of the intercept is related to the overall numerical aperture of the optical system. Each calibration curve permits the true width of a cylindrical object to be estimated by phase contrast microscopy with an accuracy of better than ±0.05 μm. We have found that greater precision is obtained by taking measurements of light micrographs subjectively using a microcomparator rather than objectively using a microdensito

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1985.tb02562.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY