摘要:

SUMMARYA system is described for rapid, simultaneous three colour elemental mapping with a scanning electron microscope (SEM) and an energy dispersive X‐ray analyser. The technique, which uses a SEM scanning at TV rate, minimizes the disadvantages of long scan times such as inefficient use of linear amplifier and observable dead‐time shadowing. The system also employs a digital scan‐stop assembly utilizing a light pen to rapidly and reproducibly direct the beam to an object of choice for spot‐mode analysis. Application of the system to analysis of fine particulates with emphasis on fly ash derived from coal‐fired electric power plants is discussed. Chemical heterogeneity of fine particles in standard reference material fly ash and in phagocytized fly ash within pulmonary macrophages is demonstrated.This system combines the morphologic capability of the SEM with X‐ray multielement mapping to provide a needed tool for particulate source ide

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1977.tb00019.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

SUMMARYWhen energy‐dispersive X‐ray microanalysis is practised in a scanning electron microscope, most of the spectral background may come from electrons entering the detector. This background can be eliminated by deflecting magnets. Alternatively, the electrons can be blocked by a plastic film but only at the cost of suppression of the low‐energy end of the X‐ray s

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1977.tb00020.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

SUMMARYThe X‐ray microanalysis of thin foils has been investigated using a scanning transmission electron microscope fitted with an energy dispersive spectrometer. Thin foils prepared from an iron‐nickel and an aluminium‐zinc‐magnesium‐copper alloy have been observed and analysed. For foil thicknesses between 200 and 300 nm the X‐ray intenstiy ratios are consistent with X‐ray absorption characteristics. For regions less than 200 nm thickness the measured intensity ratios increase by up to a factor of 5. These results have been explained in terms of a solute enriched or depleted surface layer developed during the preparat

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1977.tb00021.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

SUMMARYA computer simulation of the random linear intersecting process has been used to derive the relative frequency distributions of random intercepts through selected convex shapes. The classes of shapes chosen for investigation were ellipsoids, rounded cubes, orthogonally‐faceted spheres, rectangular prisms and triangular prisms. Certain shape‐related characteristics of the distributions are pointed

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1977.tb00022.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

SUMMARYA novel hinged device for freeze‐fracturing of cell monolayers in the Balzers freeze‐etch unit is described. It is economical on biological material and enables oriented adsorption of sheet‐like membrane fragments.For freeze‐fracturing ‘by hand’ a monolayer is formed on a positively charged piece of mica (with polylysine) and this is covered with another piece of mica, thin brass plate or filter paper. Such a sandwich is frozen in liquid nitrogen and fractured by means of forceps. Several modifications of this technique as well as practical examples are described. Among possible applications are: negative staining of intramembranous protein particles; chemical or physical analyses of single membrane leaflets; identification of protein complexes by immunoelectron micr

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1977.tb00023.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

SUMMARYZone‐refined aluminium and dilute alloys with silicon and indium have been irradiated inside a high voltage electron microscope. Interstitial dislocation loops nucleated and grew in all samples, but no voids could be observed. The precipitation of silicon was observed during irradiation. The effect of alloying on the loop growth rate is discusse

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1977.tb00024.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

SUMMARYA method of sample preparation for scanning electron microscopy (SEM) studies based on the use of stainless steel discs as a cell culture substratum is described in detail. A number of different cell lines were grown on stainless steel, and the growth patterns and biocompatibility of cells cultured on stainless steel were compared to identical cells cultured on aluminium, glass and plastic substrata. Stainless steel provides cells with an excellent growth surface which allows these cells to retain their normal growth characteristics and appearance. The non‐toxic stainless steel discs can be manipulated through any combination of fixatives and organic solvents. The discs have been incorporated into a versatile system of sample preparation for SE

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1977.tb00025.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

SUMMARYA simple electron beam gun for platinum shadowing of freeze‐fractured or freeze‐etched surfaces is described. In the Steere‐Denton freeze‐etch instrument, this inexpensive device consistently yielded high quality replicas. The compact design possibly renders this gun operable in most freeze‐etch in

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1977.tb00026.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

SUMMARYThe average thickness of the thyroid epithelial cells may be determined either directly or indirectly. By the direct or caliper method, this thickness is overestimated as a result of which its empirical value must be divided by a correction factorKd. By the indirect method, on the other hand, the thickness of the thyroid gland epithelium is calculated as the ratio of the double volume density of the epithelium to the sum of the inner and the outer surface density of the epithelium; in this case the sought for thickness value is underestimated and must consequently be multiplied by a factorKi.Both correction factors are algebraically defined. Their values are calculated and graphically represented as a function of the thyroid activation index (the ratio between the volume density of the epithelium and the colloid) for the range from 0·1 to 100.The validity of the theoretical interpretation of the discrepancy between the values obtained for the average thickness of the thyroid epithelium by the direct and the corresponding values obtained by the indirect method, is empirically tested. It is shown that by the introduction of appropriate correction factors the difference between the results obtained by each method can be reduced. These improved direct and indirect methods for determining the wall thickness of a hollow sphere seem to lend themselves to being used in the stereological analysis of other biological, perhaps even non‐biological materials of similar structu

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1977.tb00027.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

SUMMARYProteins were stained (brilliant red) by using 0·5% Ponceau 2R (C.I. 16150) in sulphuric acid (pH 2) at 40°C on sections 1–2 μm thick of tissues fixed in glutaraldehyde‐osmium tetroxide and embedded in epoxy resins. The staining is free from precipitates and does not require the removal of the embedding media.Section bleaching with 1–2% periodic acid at 40°C for 30–90 min was also carried out in order to obtain a more brilliant colour of the proteins which may be photographed using black and

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1977.tb00028.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY