ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1981.tb01192.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

SUMMARYA new stereological technique for investigating the relative positions of different phases within a material is presented. The method can be used both to quantify the degree of inhomogeneity within a specimen, and to compare the shapes and internal structures of individual features in the specimen. It can be adapted either to manual point counting or to automated image measurement.

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1981.tb01193.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

SUMMARYThe relationship between the inflection point count on a representative microsection and the integral‐asymptotoic line curvature of saddle surface in the system constitutes a new fundamental stereological equation. While the geometric meaning of this quantity cannot be readily visualized, it is unambiguous, and general for all structures. Combinations of the inflection point count with other descriptors of two‐dimensional structures provide potentially useful descriptors of particle roughness, scale, and some aspects of shape. Like all measures of boundary properties, the inflection point count is sensitive to resolution; it is thus essential to report the level of resolution in conjuction with any experimental determination o

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1981.tb01194.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

SUMMARYAttention is paid to the random curve (or curves) of intersection of a fixed surface in a spatial specimen by a random plane through that specimen. A formula is given for the expectation of the integral of a general function of curvature along that curve. This in turn yields a large family of formulae for stereological ratios.

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1981.tb01195.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

SUMMARYA method is proposed for testing the randomness of the location of an organelle within a given area of a cell section. The approach chosen is to analyse the distance between this organelle and a specific point considered as a point of reference. The method consists of converting this distance into the ratio of one given area to another and comparing the statistical distribution of the converted values to the uniform distribution. This method has the advantage of being valid in the absence of any restrictive assumptions concerning the heterogeneity in size and/or shape of the collection of sections sampled. Detailed examples are given to illustrate the practical use of the method, and its possible extensions are discussed.

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1981.tb01196.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

SUMMARYLetXbe a phase in a specimen. Given two arbitrary pointsxandyofX, let us define the numberdx(x, y) as follows:dx(x, y) is the greatest lower bound of the lengths of the arcs inXending at pointsxandy, if such arcs exist, and + ∞ if not. The functiondXis a distance function, called ‘geodesic distance’. Note that ifxandybelong to two disjoint connected components ofX, dx(x, y) = + ∞. In other words,dxseems to be an appropriate distance function to deal with connectivity problems.In the metric space (X, dx), all the classical morphological transformations (dilation, erosion, skeletonizations, etc.) can be defined. The geodesic distancedxalso provides rigourous definitions of topological transformations, which can be performed by automatic image analysers with the help of iterative algorithms.All these notions are illustrated with several examples (definition of the length of a fibre; automatic detection of cells having at least one nucleus, or having exactly a single nucleus; definitions of the geodesic centre and of the ends of a particle without holes, etc.). As an application, a general problem of segmentation is treated (automatic separation of balls in a polished s

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1981.tb01197.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

SUMMARYEstimating surface and volume density of subcellular membrane systems at different magnifications yield different results. As the magnification is increased from × 18,000 to × 130,000 the estimates of surface density of endoplasmic reticulum and inner mitochondrial membranes increase by a factor of 3, whereas that for outer mitochondrial membranes increases only by 20%. The estimate of volume density of endoplasmic reticulum also increases by a factor of 3. No further increase is observed at magnifications above × 130,000 which is therefore called critical magnification. The findings are interpreted on the basis of the concept of fractals proposed by Mandelbrot, and the fractal dimensions of the membrane systems considered are estimated. This can lead to the derivation of resolution correction factors which permit measurements obtained at any magnification to be converted to estimates at critical magnification. These findings may explain, at least in part, the large discrepancy in the estimates of the surface of cytomembranes found in the literatu

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1981.tb01198.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

SUMMARYThe aim of the sampling design for stereology is to obtain the maximal amount of quantitative structural information at a given total cost or effort. Principles of such optimal designs are discussed and methods for generating them are illustrated by a biological example. In general, the variation between different individuals—the biological variation—is the major determinant of overall efficiency, whereas the variation between single microscopic features is unimportant. It follows that the expenditure of time and/or money in order to increase the precision of the individual measurements is irrational in almost all studies where the emphasis is on the biological resu

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1981.tb01199.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

SUMMARYAn evaluation is made of the relative efficiency (precision of the final estimate per unit time of measurement on a given set of sections) of different methods for planar analysis aimed at estimating aggregate, overall stereological parameters (such asVv, Sv). The methods tested are point‐counting with different densities of test points (4 ≤PT≤ 900 per picture), semiautomatic computer image analysis with MOP and automatic image analysis with Quantimet, for obtainingVvandSvestimates. One biological sample as well as three synthetic model structures with known coefficients of variation between sections are used. The standard error of an estimate is mainly determined by the coefficient of variation between sampling units (= sections in the present paper) so that measuring each sample unit with a very high precision is not necessary. Automatic image analysis and point‐counting with a 100‐point grid were the most efficient methods for reducing the relative standard errors of theVvandSvestimates to equivalent levels in the synthetic models. Using a 64‐point grid was as precise, and about 11 times faster than using a tracing device for obtaining the estimate ofVvin the biolog

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1981.tb01200.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

SUMMARYIn this paper mathematical morphology is applied to describe the microstructural changes of metal powders during sintering. We show which morphological parameters are accessible to rapid and automatic methods. Of these parameters the change in the connectivity number and the concavity number enable the various stages of sintering to be distinguished. Moreover the growth of the necks between powder particles can be followed using a morphological method of analysis to reveal them. This method can be applied to the investigation of the microstructure of any material consisting of convex grains.

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1981.tb01201.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY