bluuebunny/crossref_metadata_2025_split huggingface dataset:
A comprehensive set of stereological formulae for embedded aggregates of not‐necessarily‐convex particles
Authors: Miles R. E. 
Published: August 2011

SUMMARYTheoretical stereological approaches to particle aggregates characteristically suppose that each particle is convex, so that upon sectioning, each particle gives rise to either 0 or 1 convex planar profile. Actually, the essential requirement in such approaches is that each planar section profile be connected; such particles need not be convex.In this paper, aggregates of quite general non‐convex particles, whose individual planar section profiles may thus comprise a number of disjoint connected regions, are considered. For this, it is necessary to anticipate the ultimate technical development of ultra‐sensitive devices (or other methods) capable of identifying in a planar section those disjoint connected regions stemming from the same particle. With this assumption, it is shown how, using the ‘4‐linc’—a new line section characteristic—to estimate the aggregate volume moment ratio , the standard isotropic section theory fully extends. To complete the picture, the recent development by Jensen & Gundersen of estimators for is extended to the ‘restricted’ case considered here. Allowing the particle volume distribution to belong to a two‐parameter family, these two parameters, Nv and the aggregate mean values may all be estimated.
Stereological estimation of the volume‐weighted mean volume of arbitrary particles observed on random sections*
Authors: Gundersen H. J. G. , Jensen E. B. 
Published: August 2011

SUMMARYA stereological estimator of the weighted mean volume of particles of arbitrary shape is described. This unbiased estimator is based on simple point‐sampling of linear intercept lengths. The complete absence of shape assumptions effectively breaks the long‐standing ‘convexity‐barrier’: the only requirement here is that individual particles can be unambiguously identified by their profiles on random sections. Practical details of the simple estimation procedure and an example with very irregular particles are reported. Finally, an estimator of the variance of the weighted distribution of particle volume is discussed. This estimator is also valid for particles of arbitrary shape. For any mixture of ellipsoids (spheres, oblates, prolates and triaxial ellipsoids) the estimator is reduced to a simple function of measurements of diameters in the section plane.
Signed line intercept count
Authors: DeHoff R. T. 
Published: August 2011

SUMMARYElements of surfaces that bound a phase (β) in a two phase mixture (α+β) may be classified as: (a) convex (++) if both principal curvatures are positive; (b) concave (− −) if both are negative; and (c) saddle (+ −) if one is positive and the other negative. This classification excludes the limiting cases for which one or both of the principal curvatures is zero. The traces of these surfaces that form the boundaries of the β areas on a representative two dimensional section may also be: (a) convex (+) if the local curvature is positive; or (b) concave (−) if it is negative. Line intercepts may be tabulated separately for intersections with convex (+) and concave (−) segments of boundary. This paper presents a derivation of fundamental stereological formulae that relate these counting measurements to three‐dimensional geometric properties of the structure they sample.
The use of pattern recognition for classification of stochastic specïmens by a set of standard specimens
Authors: Vollath D. 
Published: August 2011

SUMMARYThis paper describes an empirical method for the experimental assigning of specimens to a set of standard specimens. The procedure was developed especially for stochastic scenes. Typical applications of such a procedure are found in material sciences in assigning specimens to a standard series. The assignment is based on feature vectors obtained from analyses of the specimen texture by means of erosion or opening. In cases where the arrangement of particles is characteristic of the specimen, dilation or closing are used to obtain a feature vector. To increase the sensitivity of the method described the use of more than one structuring element is recommended in the analysis. Besides the classification of an unknown specimen the procedure provides information on the separability of the standard specimen and the significance of assignment.
Laser produced plasmas as intense X‐ray sources for microscopy at the Central Laser Facility
Authors: Rumsby P. T. 
Published: August 2011

SUMMARYSome of the X‐ray microscopy work being performed at the Central Laser Facility (CLF) is reviewed. The X‐ray sources generated by the high power glass and gas lasers, Vulcan and Sprite, are discussed and compared with other sources. The instrumentation used to perform X‐ray microscopy of laser driven implosions at the CLF is outlined and the results obtained shown. Other experimental work utilizing the intense X‐ray emission properties of laser produced plasmas is reviewed and details of work involving X‐ray diffraction, EXAFS and X‐ray microscopy of biological samples is given.
Synchrotron radiation applied to the microscopical examination of solid state and biological materials in the X‐ray region
Authors: Duke P. J. 
Published: August 2011

SUMMARYThe paper describes the properties of synchrotron radiation and makes some comparison with other X‐ray sources. The use of synchrotron radiation for various types of X‐ray imaging is discussed with reference to specific examples drawn from work carried out recently at the SERC Daresbury Laboratory.
Developments in contact X‐ray microscopy in biomedical research
Authors: Davies R. Ll. , Flores N. A. , Pye J. K. 
Published: August 2011

SUMMARYContact X‐ray microscopy (microradiography) is a method of studying the microstructure of biological tissue. These techniques have been used to study the historadiological details of human breast tissue and sections of human ear ossicles. X‐ray microscopy can also be used to demonstrate variations in structural densities seen in histological specimens including the detection of microcalcification. A modification of existing apparatus is described which has resulted in improved image‐contrast and detail.The ability of X‐rays to penetrate relatively thick sections of tissue makes it an ideal method for studying the morphology of biological structures, particularly in calcified tissue. The tissues may be further examined by conventional histology, elemental analysis, etc. The technique has a complementary role to alternative methods of tissue microscopy.
Absorption microanalysis with a scanning soft X‐ray microscope: mapping the distribution of calcium in bone
Authors: Kennedy J. M. , Jacobsen C. , Kirz J. , Rarback H. , Cinotti F. , Thomlinson W. , Rosser R. , Schidlovsky G. 
Published: August 2011

SUMMARYThis article describes the scanning transmission X‐ray microscope operated at the National Synchroton Light Source. The application of the instrument to elemental analysis is detailed. In particular, qualitative results on the calcium distribution in human skull tissue are presented.
X‐ray microscopy using computerized axial tomography
Authors: Elliott J. C. , Dover S.D. 
Published: August 2011

SUMMARYComputerized axial tomography with MoKa X‐radiation has been used to study a 0.8times0.8 mm column of human femoral bone at a resolution of 15 μm. This non‐destructive X‐ray microscopic technique allowed ‘sections' to be made with 25 μm separation and the distribution of linear absorption coefficient in each section to be determined.
Recollections of the early days of SEM in the Cambridge University Engineering Department, 1948–53
Authors: McMullan D. 
Published: August 2011

SUMMARYAfter a brief survey of the early development of the scanning electron microscope in Germany and the U.S.A., the paper describes the work on the subject that was carried out in the Cambridge University Engineering Department, particularly in the years 1948–53. This and later work led directly to the Stereoscan SEM marketed by the Cambridge Instrument Company in 1965. The paper is illustrated with a number of micrographs produced by early scanning electron microscopes.
High resolution electron beam fabrication: a brief review of experimental studies that began at Cambridge University in 1962
Authors: Broers A. N. 
Published: August 2011

SUMMARYElectron beam fabrication studies with the scanning electron microscope began at Cambridge University in 1962. Early experiments demonstrated that structures could be made that were smaller than could be made by other methods, but it was not until several years later at IBM Research that useful devices with these smaller dimensions were made. It was even later (1981) before the resolution limits of electron beam lithography with conventional resist were measured. It is now understood that with conventional resists, electron/resist interaction effects limit the minimum structure size to about 10 nm. Newer methods that involve the direct sublimation of materials such as NaCl and LiF allow structures down to about 1 nm to be made.
An X‐ray diffraction analysis of rat tail tendons treated with Cupromeronic Blue
Authors: Meek K. M. , Scott J. E. , Nave C. 
Published: August 2011

SUMMARYCupromeronic Blue was used to stain selectively the proteoglycans in rat tail tendons under ‘critical electrolyte’ conditions. Earlier electron microscopical observations indicated that at least one type of proteoglycan filament is associated with tendon collagen fibrils at the positive staining band ‘d’. To ensure that this was not an artefact caused by specimen preparation or the subsequent positive staining of the collagen fibrils, we have analysed low angle meridional diffraction patterns from stained but not dehydrated, embedded or counterstained tissues. Axial electron density profiles of Cupromeronic Blue‐stained compared with unstained rat tail tendons revealed the axial locations and relative amounts of dye in both mature and young wet specimens.In mature tendons, the difference electron density profile contained a broad peak centred near residue 180 along the 234‐residue D‐period. This corresponds to the electron‐optical staining band ‘d’. In young tendons a similar distribution of stain was observed although in this case there was evidence of a doublet of peaks, one centred near residue 182 (band ‘d’) and the other near residue 165 (midway between bands d and e1).The wet proteoglycan‐Cupromeronic Blue complexes distribute over about 30 nm along the collagen fibril axis. Comparison with the images of filaments seen in the electron microscope suggests that the dye complexes collapse significantly on dehydration and embedding.
Plunge‐cooling of tissue blocks: determinants of cooling rates
Authors: Ryan Keith P. , Purse David H. 
Published: August 2011

SUMMARYTissue blocks have been plunged into a liquid coolant and the resultant ice‐crystal damage is discussed. Some blocks have been frozen without apparent ice‐crystal damage; they were not treated with cryo‐protectants but were mounted on streamlined foil supports which separated the specimen from the thermal mass of the support pin. Hydrated gelatin specimens of various sizes have been built around thermocouples and plunged at different speeds. Results show that cooling is relatively slow in specimens mounted on solid metal supports. In specimens mounted on foil supports cooling is related to plunge velocity in 0.25 mm diameter specimens but in 1 mm diameter specimens cooling occurs mainly after coming to rest. In 0.5 mm diameter specimens cooling is related to plunge velocity at low immersion speeds but then it decreases with increasing plunge velocity; this trend should allow monitoring of attempts to improve the efficiency of the plunge‐cooling technique.
Specimen preparation methods for the examination of surfaces and interfaces in the transmission electron microscope
Authors: Newcomb S. B. , Boothroyd C. B. , Stobbs W. M. 
Published: August 2011

SUMMARYVarious techniques for the preparation of cross‐sectional and plan view TEM specimens of surfaces and interfaces are described. Particular emphasis is given to preparative methods which are both generally applicable and which minimize differential thinning of the materials present on either side of the interface of interest, thereby improving the reliability of the approach.
Electron microscopy of oxide scales modified to resist high‐temperature oxidation
Authors: Chadwick A. T. , Taylor R. I. 
Published: August 2011

SUMMARYThe high temperature oxidation of metals and alloys is slowed to a useful extent by the presence of certain elements or their oxides in the metal or on its surface. Particles of the reactive element oxide are found in part of the oxide scale and, by an unknown mechanism, retard the diffusion of metal through oxide grain boundaries. Changes in texture are also observed, which might affect geometry of individual grain boundaries. In this study the rotational geometry of grain boundaries in nickel oxide scales has been characterized both in the presence of particles of cerium dioxide and in their absence. Proximity of the relationship of neighbouring grains to a coincidence orientation could have an important influence on diffusion rate. Ways of testing this are compared and a new method for analysing orientation data from electron diffraction is presented, which allows statistically sound conclusions to be drawn. The frequency of occurrence of coincidence orientations in the presence of CeO2 is little greater than random, so one possible mechanism for the ‘reactive element effect’ may be rejected.
Analysis of ceramic materials by electron spectroscopy
Authors: Watts J. F. 
Published: August 2011

SUMMARYThe basic principles of X‐ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy are described and their relative advantages as analysis methods for ceramic materials are reviewed. Their application in ceramics technology is illustrated by examples taken from the fields of catalysis and mineralogy. In particular, attention is drawn to recent developments of XPS which make it especially attractive for the study of ceramic materials. These include quantitative application of the X‐ray photoelectron diffraction effect to layered, single crystal minerals; the development of higher energy X‐ray sources for XPS, and the attendant study of the Sils–KLL Auger parameter as a probe of molecular and crystalline structure; and the analysis of small (≃250 μm) surface features by XPS.
Stroboscopic testing of LSIs with low voltage scanning electron microscope
Authors: Todokoro H. , Yoneda S. , Yamaguchi K. , Fukuhara S. , Komoda T. 
Published: August 2011

SUMMARYA stroboscopic scanning‐ electron microscope (SEM) with 1 keV electrons has been developed to analyse the internal voltage waveforms in very large scale integrated circuits (VLSIs). A field emission gun and a short focal length objective lens are used to obtain a fine probe. Secondary electrons returning up through the objective lens are detected and analysed by a hemispherical retarding field energy analyser. The working distance of the objective lens is 3 mm, and a small stable probe of 0.1 μm in diameter with 1.6 nA in beam current is obtained. The linearity of the potential measurement is fairly good in spite of analysing secondary electrons which pass through the magnetic field. A minimum time resolution of 500 ps as well as a voltage resolution of 50 mV can be measured. This stroboscopic SEM has been successfully applied to evaluation of high speed waveforms in a ECL‐4K bit bipolar RAM.
Fine structure in electron channelling patterns
Authors: Madden M. C. , Hren J. J. 
Published: August 2011

SUMMARYElectron channelling patterns contain information from high index planes lying in the first order Laue zone. These lines are prominent in the area immediately surrounding low index poles, and can be indexed using procedures similar to those used for convergent beam electron diffraction. They reflect the lattice symmetry more clearly than the overall channelling pattern, and their exact geometry is sensitive to both lattice parameter and accelerating potential. They should also be sensitive to elastic strain.
Images of arterioles in unfixed tissue obtained by acoustic microscopy
Authors: Neild T. O. , Attal J. , Saurel J. M. 
Published: August 2011

SUMMARYA scanning acoustic microscope operating at 600 MHz was used to observe arterioles in a thin sheet of collagenous connective tissue dissected from the submucosa of the guinea‐pig small intestine. The arterioles were clearly defined in images made using transmitted ultrasound, and the acoustic attenuation (α) of the arteriolar wall was estimated to be 120 cm−1. Images made using reflected ultrasound did not show the arterioles clearly.
Towards more precise definition of conditions for satisfactory deep etching
Authors: Haggis G. H. 
Published: August 2011

SUMMARYExperiments were carried out to determine whether propane‐jet freezing could be as satisfactory as impact freezing in deep etch work. The material used was the intestinal brush border, previously studied by Heuser and coworkers where the 5–6 nm decoration of actin rootlet filaments, and the fine network of filaments linking these rootlets, provide good criteria by which to judge the quality of the preparation, as regards ice crystal growth and surface contamination. Propane jet freezing was indeed found satisfactory provided appropriate conditions were met (viz thin specimen, fracture near the surface). Variable results were obtained until it was realized that with a Balzers freeze‐etch unit fitted with a rotating specimen table there is a 10–15 min delay (when specimen temperature is reset) between the time the recording thermocouple shows a given temperature to have been obtained and the time the specimen block actually reaches this temperature. Appropriate allowance must be made for this lag to achieve satisfactory deep etch replicas.
Microscopic spectral imaging using a video camera
Authors: Balaban R. S. , Kurtz I. , Cascio H. E. , Smith P. D. 
Published: August 2011

SUMMARYA technique is described which permits the simultaneous acquisition of multiple fluorescent emission and/or absorption spectra from discrete regions of a specimen under microscopic observation. The instrument consists of a modified inverted microscope, an optical diffraction grating, a silicon intensified target (SIT) camera, and a digital video image processor. Observation of the zero diffraction order of the grating with the SIT camera permits an optical slice of the specimen to be selected by positioning the region of interest over the entrance slit of the grating housing. To obtain the spectral characteristics of this optical slice, the grating is rotated to impinge the first order diffraction on the camera. The video image of this first order diffraction maintains spatial integrity along the slit's long axis and provides spectral dispersion on the perpendicular axis. Thus, each of the horizontal video lines along the long axis of the slit represents a spectral analysis of the corresponding spatial location within the specimen. The spectral resolution (0.2 nm/channel) of each video line is determined by the resolution of the camera system in conjunction with the resolution of the grating. The image processing system acquires and processes all 500 spectra in 33 ms and permits the accurate localization of the source of each spectrum in the slice. This type of topological spectral analysis permits the determination of both spatial and spectral characteristics of intrinsic or extrinsic chromophores within the specimen. In addition, this technique permits the detection of and the possible correction for photobleaching, light scattering and image plane effects. The application of this technique to the study of single cells is discussed and an example of the technique in determining the fluorescence spectra of acridine orange within the nucleus of an intact mammalian blastocyst is described.
Quantitative DNA measurements in an instrument combining scanning electron microscopy and light microscopy
Authors: Wouters C. H. , Koerten H. K. , Bonnet J. , Daems W. Th. , Ploem J. S. 
Published: August 2011

SUMMARYAn instrument for combined scanning electron microscopy (SEM) and light microscopy (LM) to which a photometer unit is attached is described. A special stage in the vacuum chamber of a scanning electron microscope incorporates light microscope optics (objective and condenser) designed for transmission and epi‐illumination fluorescence LM. An optical bridge connects these optics to a light microscope, without objective and condenser. The possibility of performing quantitative DNA measurements in this combined microscope (the LM/SEM) was tested using preparations of either chicken erythrocytes, human lymphocytes, or mouse liver cells. The cells were fixed, brought on a cover‐glass, quantitatively stained for DNA, dehydrated, and critical point dried (CPD). After mounting the cells were coated with gold. The specimens were brought into the vacuum chamber of the combined microscope and individual cells were studied with SEM and LM. Simultaneously DNA measurements were performed by means of the photometer unit attached to the microscope. It is shown in this study that DNA measurements of cells in the combined microscope give similar results when compared to DNA measurements of embedded cells performed with a conventional fluorescence microscope. Furthermore, it is shown that although the gold layer covering the LM/SEM specimens weakens the fluorescence signal, it does not interfere with the DNA measurements.
Demonstration of pseudorabies virus DNA in the mouse inner ear by an in situ nucleic acid hybridization technique in plastic embedded bony material
Authors: Falser N. , Bandtlow I. , Haus M. , Wolf H. 
Published: August 2011

SUMMARYThis investigation is concerned with the possibility of identifying viral DNA using the in situ DNA hybridization method in methylmethacrylate‐embedded material. As an experimental model we chose viral labyrinthitis produced by intranasal infection of the mouse with pseudorabies virus. Fixation and embedding methods specially adapted to this procedure and bony histology preparation technique (specimens by grinding or micromilling) made it possible to identify viral DNA directly morphologically and virologically in the inner ear. Quantitative microphotometric analyses of trans‐sagittal sections of the entire skull after in situ DNA hybridization are presented and discussed here as an explicit method of investigating the path of distribution of viral DNA in the brain and the inner ear.
Surface exchange area of the porcine placenta: morphometry of anisotropic interdigitating microvilli
Authors: Hasselager Erik 
Published: August 2011

SUMMARYThe pig has a diffuse epitheliochorial placenta. The foeto‐maternal surface area (SV(F), SV(M)) is enlarged at three levels: level I: macroscopic folds of uterine mucosa covered by foetal membranes; level II: light microscopic folds of uterine epithelium covered by trophoblastic epithelium; level III: ultrastructural formation of both maternal and foetal microvilli in an interdigitating pattern.This study presents a morphometric method, using intersection counting, to estimate the surface area of these interdigitating, highly oriented microvilli at level III, i.e. the ‘true’ surface exchange area. The method is applied to different stages in pregnancy.The epithelial surfaces are enlarged by a factor 8–11 due to the formation of microvilli. This factor varies during pregnancy, being lower early in gestation and before delivery, and for the first time it is shown to be significantly different for mother and foetus. At level III the foetal surface of placenta is larger than the maternal indicating that the two opposing surfaces are not congruent at the ultrastructural level and that membrane‐linked placental transport may be different in mother and foetus. A three‐compartment model is suggested for placental exchange with maternal, intermicrovillous and foetal compartments.