bluuebunny/crossref_metadata_2025 huggingface dataset:
Aspects of scanning microdensitometry I. Stray light (glare)
Authors: Goldstein D. J.
Published: August 2011

Glare or stray light, an important source of error in microdensitometry, is mainly due to reflections at glass‐air surfaces in the microscope objective, and much less to imperfections in other parts of the optical system. It is only slightly affected by the numerical aperture of the microscope condenser, but is closely related to the area of specimen‐free field illuminated. If Ff is the amount of glare (expressed as a fraction of the intensity of the light incident on the specimen) with a given object and area of field illuminated, and F∞ is the glare with an infinite field size or an infinitesimally small object, F∞ approximately equals FfA/(A ‐ a), where A is the area of the whole field illuminated and a is the area of the specimen itself.

Glare with a given specimen and under given conditions of illumination may be taken to equal the apparent transmittance of an opaque object of the same size as the specimen to be measured, provided the opaque object is light absorbing (of low reflectance) and not too small (at least 5–10 μm diameter). The true absorbance Et of the specimen equals log [(1 ‐ F)/(Ip ‐ F)] where the intensity of the incident light is unity, and Ip is the apparent transmittance of the specimen in the presence of F glare. The true absorbance of a specimen is never less than F% higher than its apparent absorbance, in the presence of F% glare, and the error rises sharply with increasing absorbance. Apparent differences in the amount of dye taken up by nuclei of different sizes, stained by the Feulgen method, which have been reported by various workers and attributed to differences in DNA content, are of an order of magnitude which could be due to the presence of glare in the system. This factor should be allowed for in critical work.

Two methods of correcting the error due to glare in measurements of integrated absorbance are described. The first method utilizes data on the area of specimen containing material with an absorbance greater than a set threshold value, as provided for example by the area‐measurement facility on the Vickers M85 integrating microdensitometer. In the second, and generally preferable method, glare is compensated for electronically in a way analogous to the offsetting of the dark‐current of the photomultiplier tube of the instrument.
A histochemical and electrophoretic study of the enzymes hydrolysing certain naphthol AS esters
Authors: Fisher A. W. F. , Bulmer D.
Published: August 2011

An investigation has been carried out into the nature of the enzymes hydrolysing two substrates, naphthol AS β‐chloropropionate and naphthol AS β‐phenyl‐propionate, which have been reported as specific for the demonstration of esterases with a proteolytic activity. Parallel histochemical and electrophoretic studies on rat liver, kidney, lung, spleen, stomach and intestine show that naphthol AS chloropropionate and phenylpropionate, used in a substrate mixture containing 20% dimethyl formamide, are hydrolysed by a large number of the non‐specific esterases which hydrolyse naphthyl acetate. The histochemical investigations show a few sites where hydrolysis of naphthol AS chloropropionate and phenylpropionate occurs without hydrolysis of naphthyl acetate, but the enzymes concerned are not present in sufficient amount to show in the zymogram patterns.
Electron microscope studies of deaminated and crosslinked collagen
Authors: Grant R. A. , Cox R. W. , Kent C. M.
Published: August 2011

Glutaraldehyde‐crosslinked rat‐tail collagen, compared with native fibres, showed an increase in the size of the light bands when examined in the electron microscope using a negative‐staining technique. Collagen deaminated with nitrous acid gave similar patterns to native fibres and showed no change after treatment with glutaraldehyde. It was concluded that the increase in the size of the light bands is due to the formation of intermolecular crosslinks rather than charge neutralization of lysine amino groups.
A replica method for the examination of large specimens in the scanning electron microscope
Authors: Stirland D. J.
Published: August 2011

A simple replica technique has been used to examine larger than normal size specimens in the scanning electron microscope. Examples of the application of the method to the examination of a steel fracture surface are given, together with a discussion of the limitations of the method.
The preparation of cross‐sections of textile materials by grinding
Authors: Lomas B. , Simmens S. C.
Published: August 2011

Difficulties encountered with existing methods of obtaining cross‐sections of textile materials have been overcome by a grinding technique. This produces good, flat sections of large area and it can be used over a wide range of materials from fibres and cigarette filter tips to fabrics and metallic fibres. Little skill or experience is required and equipment costs are low.
The use of the scanning electron microscope for the study of weathered wood
Authors: Borgin Karl
Published: August 2011

The use of the scanning electron microscope for the study of the changes in the structure and ultrastructure of weathered wood was evaluated in a study of wood exposed to natural weathering for several hundred years.

Stereoscan photographs taken of the surface structure of wood revealed in detail the mechanism of the structural breakdown, which could not be found by using the light microscope or the conventional transmission electron microscope.

The gradual and very slow deterioration and ultimate destruction of the middle lamella, the various layers of the cell wall and the cohesive strength of wood tissue as well as the wood fibres are illustrated by a serious of photographs.

Since no preparative technique can be used which would interfere with the surface of the weathered wood and due to the deep three‐dimensional change in the structure, the scanning electron microscope was found to be the ideal instrument for the study of the structure of weathered wood at both high and low magnification with excellent resolution of detail.
A new technique for specimen manipulation in the scanning electron microscope
Authors: Bywater N. E. , Buckley T.
Published: August 2011

By the use of suitable DC micromotors mounted on the specimen stage of the Cambridge Scanning Electron Microscope (SEM), extra degrees of freedom may be imparted to the specimen, thus enabling a more thorough examination of a surface to be carried out. The properties that make an electric motor suitable for use inside the vacuum specimen chamber are discussed. After showing the way in which DC motors have successfully solved two problems in the fibre field, some further applications are proposed.
The statistical analysis of autoradiographs: I. Grain count distributions over uniformly labelled sources
Authors: England J. M. , Rogers A. W.
Published: August 2011

Autoradiographs have been prepared of sections of tritiated poly‐n‐butyl methacrylate (‘tritiated polymer’). Repeated visual grain counts over the sections showed good agreement with predictions from a Poisson distribution, as did similar counts of background from around the sections. Photometric measurements of grain density from the same material could also be analysed in terms of a Poisson distribution. The processes of autoradiography and grain counting whether visual or photometric, do not necessarily introduce any added variance to that attributable to the randomness of radioactive disintegration.
Field‐ion images of dilute solid solutions
Authors: Ryan H. F. , Suiter J.
Published: August 2011

Vacant‐site contrast observed in the field‐ion images of Pt‐Rh, Pt‐Au and Au‐Pd alloys is interpreted in terms of preferential evaporation of the solute atoms. Preferential retention of the solute atoms was observed in a Au‐Pt alloy. These observations conflict with predictions based on a theory of image formation proposed by Southworth & Ralph (1969).
An improved hole grid pattern for the relocation of specimens in the electron microscope
Authors: Fursey Anita
Published: August 2011

An electron‐microscope grid with circular holes arranged in a pattern indicating the orientation of the central area to the edge is described. The grids allow regions observed in a transmission electron microscope to be relocated easily or identified in lower resolution instruments.
Materials for teaching microscopy in the sixth form*
Authors: Gliddon Richard
Published: August 2011

Recent events in scientific and educational research demand that we examine critically the role of the microscope in sixth‐form biology. The advent of the electron microscope has removed the light microscope from its position as the ultimate in structural studies. The many new sixth‐form syllabuses have caused us to change from almost purely descriptive biology, with a strong emphasis on anatomy and histology, to a more balanced approach with time devoted to experimental work in such fields as physiology, biochemistry, ecology, embryology and genetics. The microscope is no longer the most expensive piece of equipment in a sixth‐form laboratory, but it is still the most versatile and valuable. It is still the best instrument we have for observing events in living materials.

With some careful thought and planning the light microscope can be effectively used in a good deal of experimental work with living or freshly prepared materials. It also enables us to miniaturize such topics as ecology and behaviour which might otherwise be neglected in urban areas. A functional approach to histology has always been the real aim of the histologist and some staining techniques help us to achieve that aim.

Quite a number of practical experiments in physiology, biochemistry and genetics also depend on use of the microscope. Behaviour, ecology and experimental embryology are all fields where materials can be successfully studied under the microscope. Some suggestions are made for suitable materials for the microscope in these experimental fields.
Preparation and mechanical requirements for freeze‐etching thick‐walled plant tissues*
Authors: Robards A. W. , Parish G. R.
Published: August 2011

The freeze‐etching technique is useful in studying cells from higher plant tissues even when thick cell walls are present. However, such cells require special consideration both in preparation for the freeze‐etching process as well as during fracturing and subsequent stages. Modifications to the technique and to the apparatus are described which make it possible to freeze‐etch thick‐walled plant tissues more successfully than by employing other methods.
A rapid method for the visual determination of size distribution of spheres from the size distribution of their sections*
Authors: Hennig August , Elias Hans
Published: August 2011

The difficulty of calculating size distributions of spheres in masses from the size distributions of sectional circles is overcome by providing standard pairs of curves representing most imaginable particle‐size distributions which might occur in nature. An observer needs only to match the histogram representing his own observations with one of the new curves to obtain immediately the size distribution of spheroid particles in his material.
The synthesis of the immobilization antigens in Paramecium aurelia: in situ localization of immobilization antigen using fluorescein‐or ferritin‐conjugated antibodies
Authors: Sinden R. E.
Published: August 2011

A technique is described for the preparation of frozen sections of a cell suspension of Paramecium, in an aqueous medium, that produces negligible ultra‐structural distortion. Incubation of osmium tetroxide‐fixed sections with fluorescein or ferritin‐conjugated globulins has revealed two extensive non‐immune reactions: namely, globulin‐tissue adsorption, and globulin‐globulin adsorption. The distribution of a group of antigenic proteins‐the immobilization antigens‐in P. aurelia was investigated using both fluorescein‐and ferritin‐conjugated globulins prepared from the sera of rabbits immunized with purified immobilization antigen. The majority of the immobilization antigen is located on the outer surface of the pellicle, but trace quantities are detected in an unresolved cytoplasmic fraction.
Electron‐probe micro‐analyser examination of worn cutting edges*
Authors: Gregory B.
Published: August 2011

A technique is outlined for wear and machinability studies on certain cemented carbide tool materials using electron‐probe micro‐analysis. Results of metallic interdiffusion and adherence are presented and are illustrated by characteristic X‐ray scanning images for certain of the chemical elements involved.
Cytochemical localization of ATP‐ase activity in plant root cells*
Authors: Hall J. L.
Published: August 2011

ATP‐ase activity in root‐tip cells of Zea mays has been localized by using a lead phosphate precipitation procedure. Activity is associated with the plasmalemma, nucleus, mitochondria, Golgi bodies, vacuoles and endoplasmic reticulum al though the relativeactivities vary in different regions of the root. The localization of surface ATP‐ase is compared with that of surface β‐glycerophosphatase and the results discussed in relation to the possible role of ATP‐ase in ion transport.
Changes induced in the ultrastmcture of the cytoplasmic and intracytoplasmic membranes of several Gram‐positivebacteria by variations in OsO4 fixation
Authors: Silva M. T.
Published: August 2011

Several Gram‐positivebacteria, belonging to different genera, fixed by the complete Ryter‐Kellenberger procedure exhibited asymmetric membranes and prominent, tubular or vesicular, intracytoplasmic membrane systems (mesosomes). When the prefixation step was omitted mesosomes were not generally observed in three of the four bacteria studied. Fixation under conditions of Ca2+ deficiency resulted in symmetric membranes and lamellar mesosomes. From the data available it is difficult to conclude which, if any, of these different patterns of membrane ultrastructure is real.
The cohesive failure of wood studied with the scanning electron microscope
Authors: Borgin Karl
Published: August 2011

The purpose of the present investigation was to establish the value and suitability of the scanning electron microscope for research on the mechanism of fracture and cohesive failure of the structure of wood. Wood samples, mainly consisting of various pines, were stressed to the point of failure in tension and shear parallel or perpendicular to the main fibre direction. The rate of loading and the temperature were varied between wide limits. The fractured surfaces were studied and gave the following results:

(1) In tension parallel to the grain, fissures developed between the microfibrils in the cell walls causing the wood to rupture perpendicular to the longitudinal axis of the fibres. At both high and low temperatures the matrix, in which the microfibrils are embedded, and to a much lesser extent the middle lamella between the fibres failed by plastic flow when the external load was applied very slowly. Under such conditions strands or bundles of microfibrils were pulled out and fractured in an irregular pattern. Cohesive failure in tension caused by sudden impact was characterized by limited slippage of microfibrils and a near brittle failure of the embedding matrix. A remarkable clean cleavage approaching a true brittle failure was observed when the wood was stressed rapidly perpendicular to the grain.

(2) Cohesive failure when the wood was exposed to shear along the grain and tension across the grain, showed clearly that the weakest part of the ultrastructure of wood under such conditions was the bonds between parallel strands of microfibrils which were pulled out with little resistance from the matrix. However, the adhesion between the middle lamella and the cell wall or the middle lamella itself failed when the wood was exposed to cleavage parallel to the grain. If the process of cleaving was carried out extremely fast, as in the machining of wood, the rheological properties of the middle lamella did not allow for plastic deformation with subsequent failure, and the bulk structure of the wood tissue behaved almost as a homogeneous material.

The use of the scanning electron microscope for the study of the structure of wood under stress and the mechanism of its cohesive failure can supply information which seems to be unobtainable by any other method.
Scanning electron microscopy of plant cuticles
Authors: Baker E. A. , Parsons Elizabeth
Published: August 2011

The scanning electron microscope (SEM) has been used to examine the structure of a wide range of different plant cuticles. The extent to which wax deposits may be damaged by mechanical abrasion in the preparative stage and by the electron probe during the scanning processes has been investigated. Techniques have been developed for the examination of the constitution of complex wax deposits and in particular of their underlying structure. Methods of preparation of isolated cuticular membranes for study by scanning electron microscopy are described. The value of wet mounting for membranes which are subject to shrinkage during drying is discussed.
High‐resolution electron microscopy of high‐modulus carbon fibres*
Authors: Crawford D. , Johnson D. J.
Published: August 2011

High‐resolution electron‐microscope images of high‐modulus carbon‐fibre fragments have been recorded under conditions which allow resolution of the individual 0.34 nm graphite layer planes. Extinction bands previously observed at low resolution are now seen to originate from several different structural features. Single bands are caused by lattice distortion due to non‐basal edge dislocations and low‐angle boundaries of tilt or twist character; periodic bands are the result of Moiré effects from overlapping or interlinked crystallites. Accurately controlled tilting experiments give further insight into the complex interlinked nature of the crystallites and the results are summarized in terms of a model which is also capable of explaining the partial recrystallization observed with boron doping.
Improvements to the functional design of the Roberts and Trevan type culture chamber
Authors: Friend J. V.
Published: August 2011

The design of the body of the cell‐culture chamber developed by Roberts & Trevan (1961) has been modified. The original chamber consists of two cover‐glasses separated by a silicone ring held together by three small screws in an aluminium alloy housing. This type of metal and method of clamping has several disadvantages. The new type of chamber, made of stainless steel which is hard‐wearing and resistant to chemicals, also includes an improved rapid method for clamping the component parts together under pressure without the danger inherent in the original of cracking the coverglasses.
Strengthening mechanisms in high strength structural steels*
Authors: Orr J.
Published: August 2011

The factors controlling the strength and impact properties of predominantly ferritic structural steels including solid‐solution strengthening, ferrite‐grain size and precipitation strengthening, have been discussed. It has been shown how individual factors can be combined to give strong‐tough structural steels. Examples of commercial and experimental steels with high strength and good impact properties have been given.
An improved apparatus for perfusion fixation with automatic pressure control
Authors: Gil Joan , Weibel Ewald R.
Published: August 2011

A method and equipment are described which allows vascular‐perfusion fixation for electron microscopy under controlled pressure conditions. Hydrostatic pressure can be kept constant during fixation by automatic adjustment of the flow rate of a peristaltic pump which is governed by a fully automatic remote‐control device. Colloid osmotic pressure of the perfusates must also be adjusted to assure adequate balance of the pressures in the tissue at physiological levels.
A new stereo‐adaptor for use with the scanning electron microscope
Authors: Unsworth A. , Hepworth A.
Published: August 2011

A description is given of a new specimen carriage and specimen holder, for use with the scanning electron microscope, to facilitate the preparation of accurate stereo‐micrographs. A detailed calibration procedure shows the apparatus to be extremely reproducible, and giving errors of less than 2% in reported stereo‐measurements.
High‐resolution surface scanning electron microscopy of mineralized tissues
Authors: Boyde A. , Broers A. N.
Published: August 2011

By using an ion‐pumped SEM with high brightness gun, resolution of the order of 5 nm has been demonstrated on the mineral matrix of animal bone and tooth enamel. Measurements of collagen fibril diameter have also been obtained.
A distortion‐free low‐magnification stage for the Hitachi HU‐11B electron microscope
Authors: Thompson D. W. , Heap P. F. , Chapman S. K.
Published: August 2011

A low‐magnification stage is described which facilitates the production of distortion‐free images in the Hitachi HU‐11B electron microscope in the range × 150–2000. The construction and method of operation of the device together with its advantages and potential uses in the material and biological sciences are considered.
Periodic acid‐Schiff‐phosphotungstic acid as an electron histochemical method for ultrathin sections
Authors: Horobin R. W. , Hague Annette
Published: August 2011

Structures which are regarded as ‘PAS positive’ may be strongly and selectively stained for electron microscopy in ultrathin sections by using the following procedure. Tissues were fixed by buffered osmium tetroxide or by glutaraldehyde followed by postfixation in osmium tetroxide. After dehydration the fixed tissues were embedded in butyl methacrylate‐methyl methacrylate (10:1 v/v). Other embedding media do not give successful results. Ultrathin sections were cut and mounted on formvar‐coated gold grids. The sections were treated with 1% w/v periodic acid in aqueous alcohol (water‐ethanol 1:1 v/v) for 10 min, washed in water for 2–3 min, then treated with Schiff reagent for 20 min. The Schiff reagent was made according to the method of de Tomasi and allowed to age for 3–5 h. The sections were then washed in two changes of water for 3–5 min each, dried in air, stained in 1% w/v aqueous phosphotungstic acid for 1.5 h then rinsed in water for 2–3 min.
Preliminary studies of the effects of DMSO on histochemical reactions
Authors: Ward P. , Smith Audrey U.
Published: August 2011

Slices of mammalian kidney were treated with concentrations of dimethyl sulphoxide (DMSO) theoretically high enough to protect living cells against damage during freezing and thawing. The blocks were cooled slowly to −45°C and then quenched in liquid nitrogen. Sections were cut at −45°C and post‐fixed in various reagents. They were stained for lysosomal and mitochondrial enzymes. Cellular and tissue morphology was better preserved than in tissue which had been treated by conventional histochemical freezing methods. The staining of the enzymes was satisfactory and the localization of mitochondrial enzymes, in particular, was sharper.
An investigation of some organic chemicals as cathodoluminescent dyes using the scanning electron microscope
Authors: De Mets M. , Lagasse A.
Published: August 2011

Thirty‐three organic chemicals have been investigated for their cathodoluminescent properties under standard conditions in the scanning electron microscope. The results are classified according to the luminescent yield of these substances and to the decrease of the luminescence after the specimen was scanned for a given time at magnifications of about × 1700 and × 3500 (beam effect). The relationship between molecular structure and luminescent yield, and the origin of the beam effect are difficult to describe. Reference has been made to data obtained from scintillation‐counting studies.
Localization in the electron microscope by acid phosphatase of casein particles in lactating mammary glands of rats
Authors: Tan W. C. , Livingston D. C. , Gilbert J. D. , Young Stretton
Published: August 2011

Caseins are phosphoproteins and contain phosphate in monoester form; acid phosphatase is a specific hydrolysing enzyme for such phosphate monoesters; and electron‐dense particles of lead phosphate can be precipitated from a solution containing lead by the hydrolysed phosphate radical. We have made use of these facts to verify that the previously described ‘protein droplets’ located within the vacuoles of mammary epithelial cells contain phosphoprotein. Since these protein particles respond to an enzyme having Phosphomonoesterase activity at the correct pH it seems likely that they contain phosphate monoester in their structure and that they are therefore most likely to be casein particles.

The method appears to have applications in the study of lactating mammary glands and the secretory activity of mammary tumours.
Lanthanum as an intracellular stain
Authors: Bannister L. H.
Published: August 2011

In mouse and fish olfactory mucosæ, lanthanum has been found to penetrate various intracellular components of cells including the endoplasmic reticulum, mitochondria, microvilli, microtubules and cilia, outlining their substructure in negative contrast when seen in sectioned specimens.

Structural details approaching those seen in disrupted negatively stained material were observed in sections, suggesting that intracellular lanthanum staining may prove a useful tool in morphological studies.
Field‐ion microscopy of iron‐molybdenum solid solutions
Authors: Papazian J. M.
Published: August 2011

The average density of bright spots in the (200) region of field‐ion microscope images is found to be related to the nominal molybdenum composition in a series of iron‐molybdenum alloys containing 1/2 to 5 weight percent molybdenum. The bright spot density is found to be proportional to the square of the tip radius and is thus linearly related to the surface area. This indicates that a correlation between the observed bright spot density and a bulk property is permissable. The bright spot density is also found to increase approximately linearly with molybdenum content, at least up to 3% molybdenum. Observation of specimens with similar amounts of molybdenum in solid solution but different nitrogen contents shows that the observed correlation is independent of the nitrogen content. Similarly, it is shown that the correlation is also independent of carbon content. Thus, it is concluded that the bright spot density is directly related to the amount of molybdenum in solid solution and can be used as a measure of the local molybdenum concentration. The nature of the bright spot contrast is discussed and is shown to be consistent with a current theory of image formation.
The use of the scanning electron microscope for comparing the structure of weak and strong egg shells
Authors: King N. R. , Robinson D. S.
Published: August 2011

A scanning electron microscopic investigation has been made of the radial fracture surfaces of both weak and strong egg shells. Generally in weak and thin egg shells the mammillae were of irregular shape, very porous, frequently not attached to the outer shell membrane fibres and were cleaved both radially and transversally during fracture.
Optical shadowing in the electron microscope
Authors: Haydon Glen B. , Lemons Ross A.
Published: August 2011

Optical shadowing offers a valuable technique for the study of many transmission electron microscope specimens. Simply blocking half of the illumination with the objective aperture produces an image with a striking shadowed effect which gives a distinctly three‐dimensional appearance to the specimen's surface topography. Theoretical analysis shows that this is due primarily to a discrimination between electrons refracted in opposite directions, and that the characteristic features of the effect are successfully explained by a refraction model. The capability of visualizing surface topography is applicable up to the full resolving power of the instrument and accordingly opens many new avenues of investigation.
Some observations on the filaments of frozen‐etched striated muscle
Authors: Willison J. H. M. , Cocking E. C. , Lawrie R. A.
Published: August 2011

Frozen‐etched rabbit psoas muscle and locust flight muscle are illustrated. The myofibril structure of striated muscle as seen by freeze‐etching is wholly compatible with the well‐established interdigitating sliding filament model. A major difficulty in interpretation arises from the detailed appearance of projecting myofilaments which arise when myofibrils lie obliquely to the fracture plane. They appear to be surrounded by a grey halo, with a light central spot, but without sufficient projection to account for the length of the shadow. The grey halo consists of undissolved myosin released from the replicated projecting myofilament during the drying of the replica following cleaning. It may be removed by recleaning. The surface tension forces involved in removing the myosin from its casing, however, cause the case itself to be destroyed, leaving a phantom shadow. The light, central spot is a resultant hole in the replica. Thick and thin filaments are found in longitudinally fractured myofibrils. There is a close correspondence with the images of frozen‐etched muscle from previous work.
Graphic three‐dimensional representations from serial sections*
Authors: Dunn Robert F.
Published: August 2011

A method is described whereby steric configurations and surface contours may be produced in schematic form from serial light or electron micrographs. The resultant illustration, similar to those used by cartographers, is easily prepared and obviates the necessity of publishing large numbers of half‐tone micrographs to substantiate the analysis.
Negative staining of viruses
Authors: Nermut M. V.
Published: August 2011

Several techniques and procedures of negative staining are described and compared from the point of view of both ‘drying’ and ‘specific staining’ artefacts. These are shown on examples from several virus species. The ‘drying artefacts’ can be prevented using the freeze‐drying technique or reduced using ‘paper‐filtration’, ‘pseudoreplication’ or the Kleinschmidt techniques. The ‘specific staining’ artefacts can be avoided by using another stain which does not affect the structure under study. Different ways are shown to stain the surface or the interior of virus particles.
A microscopical examination of an alleged 1933 penny
Authors: Green L. , Moon J. R.
Published: August 2011

An alleged 1933 penny has been examined by scanning electron microscopy and microprobe analysis. It was shown that the penny was a forgery and a possible method of forging was deduced.
Quantitative analysis of scanning electron micrographs
Authors: Hilliard J. E.
Published: August 2011

Scanning electron microscopy (SEM) provides a considerably greater depth of field than optical microscopy at the same magnification. It is therefore particularly suitable for the examination of specimens with irregular surfaces.

This review of procedures for quantitative measurements on SEM images falls into two parts. The first deals with mensuration; that is, with the determination of the lengths, dihedral angles and other properties of specific features in the image. Particular emphasis is given to means of correcting for non‐linearity and other distortions caused by instrumental defects. The second part considers the analysis for bulk properties such as volume fraction and boundary area per unit volume. In the case where observations are made on a planar section, these properties can be determined by use of the standard stereological relationships after making a computable correction (where necessary) for the tilt of the specimen and non‐linearities in the scan. However, for irregular surfaces (for example, those produced by fracture) rigorous estimations are not possible without certain assumptions which, unfortunately, are in many cases unrealistic.
Stereology and structuring elements
Authors: Serra J.
Published: August 2011

An object's quantitative analysis is not purely objective. On the contrary, it results from the interaction of a structuring element chosen by the observer, with the object to be analysed. After defining this relation in a quantitative way (hit‐or‐miss transformation), and recalling its probabilistic interpretation (Matheron, 1971) some examples of structuring elements are given:

The couple of points which measures the covariances matrix. It allows harmonic analysis and the solving of sample problems.

The segment which measures the chord distribution, and leads to the stereo‐logical parameter ‘the star’.

The parallel segments doublet, which measures curvature radius distribution and the number of particles in the two‐dimensional space.

The hexagon, which measures bi‐dimensional granulometries, etc.

These measurements have been made on the texture analyser, built by us especially for that purpose. As a conclusion, we give an application of structuring elements to clustering measurements.
Multi‐dimensional perspectives on stereology
Authors: Miles R. E.
Published: August 2011

The structures of primary concern in Part A are varieties—the generalization in higher dimensions of smooth curves and surfaces. Fixed orientation random s‐sections (s‐dimensional flat sections) of a fixed t‐variety (t‐dimensional variety) in Rd (d‐dimensional space) are considered in Section 2. The t‐variety induces a density‐cum‐orientation distribution which is related to corresponding sectional quantities. The by now classical basic formula; of stereology are all special cases of the simple multi‐dimensional formula (2.16). Next (Section 3), statistics of the variety of intersection of several statistically homogeneous random varieties are related to the corresponding statistics of the parent varieties.

Part B is concerned with the analysis by random s‐sections of fixed aggregates of t‐dimensional opaque particles (i.e. varieties for 1 ≤ t ≤ d — 1, domains for t = d) embedded within an opaque specimen. Fixed orientation random sections are considered in Section 5, and isotropically oriented ones in Sections 6–10. It is shown in Section 7 that the mean particle ‘caliper diameter’, a key quantity, may in theory be estimated by isotropic slice sectioning. The theory is particularly rich when the particles are convex, witness the arrays of useful formula; in Sections 8–10. Crofton's remarkable ‘second theorem’ comes into its own in Section 9, permitting simple estimates from isotropic test lines of mean area squared to mean perimeter (when d = 2) and mean volume squared to mean surface area (when d = 3); in fact, the formulæ of Sections 7–9 suggest estimates for both mean and variance of the areas (when d = 2) and volumes (when d = 3) of aggregates of embedded convex particles. Further results for aggregates of convex polytopes are given in Section 10. Certain general considerations and principles relating to estimation from random sections in the practical cases, i.e. d ≤ 3, are included in the final Section 11.

Equations which are the specializations of multi‐dimensional formulæ to the practical cases are asterisked. A feature is the attention given to the proper probabilistic specification of random sections through the specimen, a matter that seems largely to have been ignored.
Rasterable pointsets
Authors: Giger Hans
Published: August 2011

A very general class ℛ of pointsets is introduced which is named rasterable.

The term ‘rasterable’ designates the important property of these pointsets that they can be represented by the raster of those points of a lattice belonging to the pointset. This representation concerns the Minkowski measures and has to be interpreted in a statistical sense.

It is shown that the directional Minkowski measures for rasterable pointsets can be interpreted as coefficients of the expansion of the corresponding correlation function. It follows that the well‐known Wiener spectrum of a two‐dimensional texture, which equals the Fourier transformation of a reduced correlation function, does not preserve the topological properties of the pointset.

The described representability of a pointset by a point picture may clarify the property of the pointset to be ‘normal’ in the common sense of the word. If one knows the pathological appearances in the theory of pointsets this clarification is of special interest.
A generalization of the concept of size
Authors: Delfiner P.
Published: August 2011

The size of a set is defined without ambiguity as a ratio of homothety with an elementary set having the same shape. In order to generalize this, we compare the object studied with the elements of the family {λB} of the homothetics of B. The size λ of a particular element B is going to act as a measure of the object.

If the latter is made up of individualized elements, we can calculate the size of each one and construct the size histogram, assuming for example that the size of a connex component C according to B is the size of the largest B included in C. (Examples: inscribed circle radius, maximum intercept.) For any object (alveolar lung space, pore system), the size at each point x is defined as the largest λB included in the object and containing x. The set of points x of a given size λ is related to the opening with respect to λB. This geometrical transformation of opening has mathematical properties similar to those of the sieving process, and is the basis of the size distribution concept as generalized by mathematical morphology.

In the plane, the texture analyser allows the above measurements.
Order‐disorder phenomena in aggregations of particles of sizes and shapes which vary randomly within limits
Authors: Moore Richard E. M.
Published: August 2011

When particles of randomly varied sizes and shapes within limits are aggregated, the expectation is that their disorder will increase as particles are added. But, depending on how disorder is measured, this is not necessarily so. It is shown mathematically that a maximum to the degree of disorder exists, and moreover, that this maximum can only be maintained by highly specialized sequences of particles thereafter. Consequently, it is probable that the degree of disorder, having first increased, will then decrease. As the degree of disorder falls, it becomes more probable that it will increase, so that the expectation is for the degree of disorder to oscillate as particles are added. If sampling sections pass through these more ordered regions the impression can arise that the structure is ordered, whereas the structure may in fact be random.
Graphic stereo‐reconstruction of serial sections
Authors: Yamada Munesato , Yoshida Shuji
Published: August 2011

Serial histological sections may be graphically reconstructed in the form of paired ‘stereo‐maps’ for observation with a stereoscope. Comfortable stereo‐vision is obtained if the contour lines which produces grades are laterally parallaxed to an appropriate degree. Since the technique is advantageous and its procedures are simple in practice, it will be applied in a number of investigations. The basis of the technique is that the parallax is achieved by staggering one of the half‐maps with a micrometer at the rate of one‐tenth the section interval, which gives rise to perspective in the stereo‐vision. Some fundamental conditions, involved in procedures as well as observation, were investigated in order to consider the nature of the final image. Thus, it has proved to be a satisfactory representation. Other than the primary reconstruction, which is observed at right angles to the sectional plane, a method to convert the viewing direction, or the profile cartography, has been developed, so that we are able to observe sectioned structures practically from any direction.
Analysis of dendrite patterns by use of an adaptive scan system*
Authors: Wyss Urs R.
Published: August 2011

A scanning procedure is described by which means morphometric parameters of dendrite tree structures may be collected with low operator interaction. The system requires a small computer with 4K core and interfacing to A/D and D/A converters, a scanning oscilloscope, a standard microscope and a photo‐multiplier tube. Modular, or local pattern information is sampled on a circular scan raster, and standardized patterns specified in terms of the number of dendrite processes scanned. These modular patterns are linked together to map a chord approximation of the object. Branches out of focus are recognized and the stage adjusted by remote control of a stepping motor. The paper records a pilot study, performed at the Department of Anatomy, University of Rochester, N. Y.
A computerized method of determining the number of synaptic contacts in a volume of cerebral cortex*
Authors: West Mark J. , Coleman Paul D. , Wyss Urs R.
Published: August 2011

A computerized flying‐spot scanning device has been used to count the number of synaptic contacts in neural tissue stained with ethanolic phosphotungstic acid (E‐PTA). The ability of the computer to idealize the irregular synaptic contacts as solid disks by modifying the information gleaned from scanning the preparation allows the stereological principle of Weibel & Gomez to be used to calculate the number of E‐PTA stained synaptic contacts per unit volume of tissue. This technique represents a significant improvement over the time necessary for making similar quantitative determinations manually.
Measurement and stereological size analysis of sized spheres
Authors: Timčák Gejza M. , Jones Meurig P.
Published: August 2011

Accurately sized copper spheres were dispersed in a ‘putty‐like’ Araldite in an attempt to achieve a random spatial distribution. Random sections were then cut through the hardened Araldite and the exposed copper circles were measured by two types of instruments; one measured the diameter of the copper circles whilst the other measured random chords across the circles.

The experimental results are compared with the results of a computer simulation of the sectioning of randomly positioned spheres.
Computer techniques in the analysis of field‐ion micrographs
Authors: Youle A. , Davies D. M. , Dury B. L. , Schwartz D. M. , Taylor D. M. , Ralph B.
Published: August 2011

The computer techniques at present used in the extraction and analysis of data from field‐ion micrographs are described. These techniques are divided into three categories: simulation of field‐ion images, the analysis of particle sizes and the determination of precipitate shapes and interface topography. The theory and techniques of each are described, together with examples of their use.
Perspectives of application of quantitive television microscopy to earth sciences
Authors: Pinault J. L. , Prevosteau J. M. , Williams D. G.
Published: August 2011

The quantitative application to earth sciences of the recent techniques of opto‐electronic methods has become possible not only thanks to new methods of sample preparation, to analysis at all levels of magnification, to progress in image analysis, but also to the mathematical formulation and evaluation of data. At the level of the light microscope (thin slice, polished section) this methodology is applicable to porous media, to powder granulometry, and to an analysis of metallic ores. As a special case, we have treated an example of the modal analysis of eight phases in an ore considered difficult from the point of view of identification and separation of the phases. At the macroscopic or geological level, we have tried to determine the hydraulic diameter of fissures and cracks, that is their orientation, working on a structural survey by simple application of stereological functions.
A general method of calculating particle size distributions
Authors: Schwartz D. M.
Published: August 2011

A general nonparametric approach to estimating the true distribution of particle sizes from either light or electron micrographs of particles of known shape is described. This method can deal with any arbitrary shape and fixed or random orientations, it assumes that the observed distribution is obtained by recording the maximum observed diameters of the particles under study. As examples, the method is applied to the distributions of both cubic particles observed in an optical metallographic specimen and spherical particles observed in a transmission electron microscope specimen.
A comparison of several methods for stereological determination of the numbers of organelles per unit volume of cytoplasm
Authors: Mayhew T. M.
Published: August 2011

Granules in electron micrographs of normal rat peritoneal macrophages were analysed using a number of stereological procedures currently available for estimating the numbers of discrete particles from measurements made on random sections. The distinction between the various procedures was dependent upon the nature of the parameters derived from micrograph samples, and upon the degree to which particle shape and size distribution coefficients were incorporated within the mathematical derivations. Whilst all methods were found to produce similar estimates of granule number per unit volume of macrophage cytoplasm, two procedures demonstrated a greater degree of flexibility of application. It is concluded that these two methods may possess important advantages when quantitating experimental systems exhibiting alterations in particle morphology.
A theory of field‐ion imaging: II. On the origin of site‐current variations*
Authors: Forbes Richard G.
Published: August 2011

Experimental evidence demonstrates the incompleteness of the usual rate constant explanation of field‐ion image appearance, and suggests that gas distribution effects may be the dominant influence on image contrast, certainly in some circumstances. Further evidence shows that gas concentration variations across the surface would not be given by any simple formal rule. However, significant features of image behaviour in the helium‐on‐tungsten system can be rationalized by closer examination of gas behaviour during and after accommodation. For the normal imaging range a provisional working rule is suggested, that regional contrast may be primarily determined by supply‐and‐capture effects, but local contrast by a tendency for local gas equilibria to be established.
Use of vibratory polishing for the location of ion‐bombardment induced voids in metal foils
Authors: Mazey D. J. , Hudson J. A. , Francis S. , Whitton J. L.
Published: August 2011

The technique of vibratory polishing has been successfully applied to the controlled removal of surfaces for examination of ion‐irradiation damage structure in nickel, a nickel‐based alloy, and stainless steel. The application of this technique to the study of voids formed in localized layers in nickel and stainless steel during high dose 20 MeV carbon ion irradiation is described. Transmission electron microscopy observations of the vibratory polished surfaces reveal mechanical damage in the form of linear tracks (∼ 100 nm wide) which are produced by the abrasive Al2O3 particles used for polishing. These tracks do not prevent observation of irradiation damage structure. An example is shown of a thin (∼ 100 nm edge thickness) foil produced entirely by this mechanical polishing process. It is proposed that this technique will be equally applicable to the preparation of transmission electron microscope specimens from a wide range of metals, from alloys containing second‐phase particles and from ceramics, glasses and oxides which are not amenable to preparation by chemical or electro‐polishing.
Electron microscope measurements: A digital read‐out across the intermediate lens
Authors: Yodaiken Ralph E.
Published: August 2011

In order to ensure reproducibility of magnification and to determine the accuracy of figures taken from the magnification meter on the side of a Siemens electron microscope, a sensitive voltmeter with a digital read‐out was put in the intermediate as well as the objective and projector lens circuits. The microscope was calibrated on different days and the results of the magnification measurements taken from the scale were compared with the results obtained using the read‐out system. The conclusions underline the necessity for exercising caution in interpreting magnification figures and suggest a relatively inexpensive method of improving reproducibility.