bluuebunny/crossref_metadata_2025 huggingface dataset:
Modification of an SEM for backscattered electron imaging at low vacuum
Authors: Kazmierski T. M. , Millington P. F.
Published: August 2011

Modifications to the Cambridge Scanning Electron microscope enable the viewing of untreated insulating materials directly with no evidence of charging. Beam damage under the conditions employed were quite small, even uncoated polythene could be viewed at magnifications of 20–2000 at 30 keV for long periods of time with little evidence of continuing changes in surface structure. Detailed descriptions of the modifications used are given. Studies on biological material were not satisfactory and work is in progress to confirm that the claims of Robinson (1975a) can be demonstrated in this type of instrument.
Energy Spectra Of Dislocations In Silicon And Germanium
Authors: Schröter Wolfgang , Scheibe Ernst , Schoen Helmut
Published: August 2011

The properties of edge‐type dislocations are strongly dependent on the temperature at which they have been introduced into the crystal. Dislocations produced at T < 0·6 Tm (Tm melting point) exhibit a richer variety of properties than those introduced at T > 0·6 Tm: in germanium a strong increase of the hole density, in silicon an electron para‐magnetic resource (EPR)‐signal, showing many fine details, and several peaks in the deep level transient spectroscopy (DLTS)‐signal, are only found after low‐temperature deformation. The increase in the hole density has been ascribed to point defect clouds, which surround the dislocation, and seem to control their mobility. The clouds are not stable at the deformation temperature.

The electrical and optical properties of edge‐type dislocations, introduced at T > 0·6 Tm into germanium, can be interpreted in terms of a half‐filled one‐dimensional band (for T ≥ 50 K), which might be due to dangling bonds in the dislocation core. In silicon the experimental data indicate a similar form of the local energy spectrum at dislocations.
Interstitial Supersaturation And Climb Of Misfit Dislocations In Phosphorus‐Diffused Silicon
Authors: Strunk H. , Gösele U. , Kolbesen B. O.
Published: August 2011

Bipolar transistors showing the‘emitter‐push effect’ have been investigated by transmission electron microscopy. From the analysis of isolated dislocation helices in the boron base and the phosphorus emitter it is concluded that the diffusion of phosphorus into silicon is coupled with a supersaturation of silicon self‐interstitials. A new generation mechanism for this supersaturation is suggested.
The Nature And Origin Of {113} Faults In Irradiated Silicon And Germanium
Authors: Salisbury I. G.
Published: August 2011

At elevated temperatures, electron irradiation damage in silicon and germanium forms faulted defects on {113} which are elongated in <110>. During the present work on silicon, these {113} faults were observed to unfault, apparently by glide, to give elongated interstitial loops with b = a/2<110>. Since the tetrahedral interstitial sites between adjacent {113}s form a full {113}, in both number and distribution, it was concluded that the atoms were accommodated in these positions.

A fault of this type comprises interstitial pairs, the atoms of which are on adjacent tetrahedral sites a/4<111> apart, and it is proposed that these already exist, or are formed, when a fault nucleates. Two‘di‐interstitials’ then close‐pack along one of the three <110>s normal to their <111> axis, thus nucleating a {112} loop. This is unable to grow in any direction other than <110>, because its habit plane is occupied by matrix atoms, so the loops become extended. The defect grows in width by nucleating further loops on {112} planes, extended parallel to the first, and the‘array’ forms an elongated {113} defect, on a plane 10° from the original {112}. This gives the observed faulted {113} loops, elongated in <110>, with R ≃/11<113>.
Electron Microscope Study Of Microtwins In Epitaxial Silicon Films On Sapphire
Authors: Lihl R. , Oppolzer H. , Pongratz P. , Skalicky P. , Svanda W.
Published: August 2011

Silicon on sapphire films were studied by TEM. The density of microtwins were closely investigated and a non‐uniform distribution with respect to the four {111} twinning planes was found. Crystallographic arguments are given to explain this non‐uniform distribution and the decrease of the fault density with the distance from the interface. Contrast analysis of the microtwins shows that most of them are not 3N‐layer twins but contain a stacking fault.
Characterization Of Grain Boundaries Observed In Polycrystalline Silicon For Solar Cell Applications
Authors: Fontaine Chantal , Rocher André
Published: August 2011

This paper describes some preliminary results concerning the TEM observations of grain boundaries in polycrystalline silicon for solar cell applications. A graphical method of grain boundary characterization has been developed. All the grain boundaries studied have been found to be characterized by twin relationships.
Electron Microscope Studies Of Vpe Gainas Layer Structures Suitable For Use As Infrared Leds
Authors: Hockly M. , Al‐Jassim M. , Booker G. R. , Nicklin R.
Published: August 2011

Electron microscope investigations have been carried out on vapour grown (100) GaAs/GaInAs structures designed for use as infrared emitters of wavelength 1·06 μm. The structures consist of a GaAs substrate, a graded layer in which the indium concentration is increased from zero to 17 atomic %, and a constant composition Ga0·83In0·17As layer which contains a p‐n junction. X‐ray microprobe analysis of cross‐sections of the slices established the uniformity of the grading. TEM analysis showed a dense and extensive asymmetric network of misfit dislocations (1 × 1012 m−2 (108 cm−2)) in the graded layer, threading dislocations and other anomalous contrast features extending from the graded layer through the p‐n junction to the surface (local densities of 1 × 1011–1 × 1012 m−2 (107–108 cm−2)), and a planar network of dislocations just below the surface (spacing 0·2–2 μm). SEM EBIC and CL studies of the layer above the junction revealed dark spots, and a cross‐grid of dark lines, which could be correlated with the threading defects, and the dislocation network just below the surface, respectively. The SEM results showed that these defects had a deleterious effect on the luminescent and electrical properties of the material in the vicinity of the p‐n junction, and would therefore impair the performance of devices made from these layer structures.
Use of differential interference contrast microscopy to determine cell renewal times in mouse intestine
Authors: Smith M. W. , Jarvis L. G.
Published: August 2011

Pieces of mouse mid jejunum have been cleared in glycerin and examined by differential interference contrast microscopy at low powers of magnification. The position and number of crypts and villi can be determined in the same specimen using this technique. The calculated value for crypt/villus ratio 4·53 ± 0·99 (mean ± SD) is less than a previously published value obtained using indirect techniques. A revised estimate of cell renewal time, based on this newly determined value for crypt/villus ratio, is 45 h. This agrees with earlier estimates derived from entirely different methods of analysis. The general usefulness of this form of light microscopy in helping one appreciate some three‐dimensional problems in mucosal architecture is emphasized.
A critical examination of the electron‐microscopical evidence for swollen hydrated cellulose fibrils in green plants
Authors: Willison J. H. M. , Brown R. M. , Mueller S. C.
Published: August 2011

The electron‐microscopical evidence for the existence of ‘nascent cellulose fibrils in green plants’ (Leppard, G.G. & Colvin, J.R., J. Microsc. 113 (1978), 181) is examined critically. It is concluded that images of pre‐shadowed carbon replicas which appear to show cell wall microfibrils having a sheath enclosing a core are unavoidable technical artefacts in which the sheath consists of the replicating carbon. This interpretation is supported by the finding of similar apparent sheaths around air‐dried microfibrils which were suspended above the main plane of the substrate surface at the time of replica‐making. It is shown that the impressions of microfibrils in fractured plasma membranes have greater cross‐sectional dimensions than the microfibrils themselves as a result of the relationship between the microfibrils and the plasma membrane, and that such impressions are not evidence of ‘nascent fibrils’. Furthermore, it is argued that there is no evidence at present which supports the hypothesis that a swollen, sheathed ‘nascent fibril’ of cellulose is produced by prokaryotic Acetobacter xylinum. A light core is demonstrated in images of unshadowed replicas of microfibrils and it is proposed that radiation damage may play a rôle in the formation of this image. It is demonstrated that the coincidence of Fresnel fringes around unshadowed defocused replicas of microfibrils can also lead to the formation of an apparent core. Problems associated with obtaining measurements from replicas of cell wall microfibrils are discussed and some recommendations are made.
Interactions of uranyl ions with lipid bilayer membranes
Authors: Ting‐Beall H. P.
Published: August 2011

Uranyl ions (UO22+), once bound to the phosphate moieties of phospholipid head groups, stabilize bimolecular lipid membranes (BLMs) as well as decrease the nonactin‐induced membrane conductance. UO22+ bind to a phosphatidyl choline‐cholesterol (2:1, molar ratio) BLM surface with a dissociation constant of 2·3 μM and a maximum change in surface potential of 88 mV, which corresponds approximately to one uranyl ion per 31 nm2 surface area. Furthermore, uranyl ions can penetrate the lipid bilayers as neutral complexes such as uranyl acetate.
A simple, combined diffractometer and scanning microdensitometer
Authors: Longley W.
Published: August 2011

A simple device for densitometering electron micrographs or other transparencies by one‐dimensional scanning is described. Micrographs of crystalline materials are oriented by means of their optical diffraction patterns displayed with a slightly modified microscope.
Nonradiative recombination at dislocations in III–V compound semiconductors
Authors: Petroff P. M. , Logan R. A. , Savage A.
Published: August 2011

Carrier recombination at individual dislocations is investigated for the case of misfit dislocations at a heterojunction between Ga1–xAlxAs1–yPy epitaxial layers. Through the combined use of scanning transmission electron microscopy, electron beam induced current and cathodoluminescence analysis, it is shown that the non‐radiative and radiative recombination properties of dislocations are associated with their fine crystallographic configuration. The edge Lomer‐Cottrell dislocation is found to be electrically neutral. The absence of carrier recombination strongly suggests that core reconstruction may be important in eliminating dangling bonds and kink sites along the core of these dislocations. An undissociated dislocation with a Burgers vector b=1/2a〈110〉 is proposed as the more likely configuration for the edge Lomer‐Cottrell dislocation. An asymmetry in the nonradiative recombination properties and crystallographic structure of the 60° dislocation is also reported and discussed.
Observation of dislocations and microplasma sites in semiconductors by direct correlations of STEBIC, STEM and ELS
Authors: Fathy D. , Sparrow T. G. , Valdrè U.
Published: August 2011

A high voltage electron microscope, equipped with scanning transmission (STEM) attachment, electron beam induced conductivity (EBIC) facilities, and electron energy loss spectrometer (ELS), has been used to investigate semiconductor devices. The capability of STEM to produce, simultaneously or sequentially, conductive and transmission images of the same specimen region, which can also be ELS analysed, is exploited in order to establish direct and unambiguous correlations between EBIC and STEM images of defective regions (dislocations and microplasma sites) in silicon devices.

The results obtained are discussed in terms of correlations, resolution, contrast, and radiation damage; in addition, a comparison is made between this method and the other correlation methods based on EBIC/SEM (scanning electron microscope) and TEM (transmission electron microscope).
Minority carrier lifetime mapping in the SEM
Authors: Steckenborn A.
Published: August 2011

A method is described for obtaining two‐dimensional distributions of minority carrier lifetimes in semiconductor materials for optoelectronic applications. The novel features of the system are: on line analogue calculation of the lifetime from the decay of the cathodoluminescence signal after switching off the SEM electron beam; simultaneous computerized mapping of the signals obtained in this manner in the scanning electron microscope. Typically, it permits establishing a map of 1 mm2 with 512 times 512 data points in 10 min for lifetimes down to 3 ns.
EBIC microscopy of double‐heterostructure laser materials and devices
Authors: Stevenson J. L. , Skeats A. P. , Heckingbottom R.
Published: August 2011

The electron beam induced current (EBIC) mode of the scanning electron microscope (SEM) has been used to characterize double heterostructure laser materials and devices in GaAs/Ga1–xAlxAs. Scanning the electron probe across the cleaved face of the laser structure shows that displacement of the p‐n junction with respect to the heterojunctions is not uncommon with displacements ∼ 1 μm occurring. Concurrent measurement of the minority carrier diffusion length gives very short lengths of 0·3–0·4 μm, differing from those in much thicker layers. Scanning the electron probe in the contact plane indicates clearly that long‐lived lasers exhibit marked heterogeneity during degradation. Considerable complexity and variation is recorded depending upon the fabrication details and degradation conditions adopted.
SEM and TEM observations of emitter‐collector pipes in bipolar transistors
Authors: Gowers J. P. , Bull C. J. , Ashburn P.
Published: August 2011

The EBIC mode of the SEM has been used to identify the sites of emitter—collector pipes in diffused npn bipolar transistors. After thinning, the same devices were studied in the TEM at 1 MV. A one‐to‐one correlation was found between the sites of the pipes and the arms of complex dislocations originating from the emitter diffusion‐induced dislocation network and looping down into the collector. The white EBIC contrast at pipes was often accompanied by adjacent black contrast due to the recombination of electrons at parts of the dislocation in the base region.
SEM and TEM studies of defects in Si‐doped GaAs substrate material before and after Zn diffusion
Authors: Darby D. B. , Augustus P. D. , Booker G. R. , Stirland D. J.
Published: August 2011

Si‐doped GaAs slices after Zn diffusion exhibited a marked decrease in luminous efficiency and a large increase in p‐n junction depth when the initial carrier concentration due to the Si was > 3·5 times 1024 m−3. SEM studies using the CL and EBIC methods, and TEM examinations using plan‐view and cross‐section specimens, showed that these behaviours were associated with high densities of structural defects, interpreted as Zn precipitation. Reasons for these behaviours in terms of nucleation behaviour and diffusion mechanisms are suggested.
X‐ray topography of large single crystals
Authors: Dineen C. , Jones F. J. , Isherwood B. J. , Wallace C. A.
Published: August 2011

A requirement exists in the fabrication of certain electronic devices for non‐destructive examinations of the structural perfection of large single crystals. Two X‐ray topographical techniques which fulfill this requirement are described.

A curved crystal transmission topography technique provides images of equivalent definition to those obtained by Lang topography, but with a very large gain in speed. This technique is restricted to the examination of flexible plates of uniform thickness and is particularly suited to silicon slices.

A topographical method, incorporating an unorthodox scanning mode, has been applied to the assessment of the surface perfection of long crystals. Using this technique, crystals up to 205 mm in length have been examined on a suitably modified Lang camera of limited traverse capability.
Measurement of radiation damage by electron energy‐loss spectroscopy
Authors: Egerton R. F.
Published: August 2011

Inner shell ionization edges in the energy‐loss spectrum were used to measure the loss of gaseous elements from thin samples of nitrocellulose, polyvinyl formal, copper phthalocyanine, graphite bisulphate and sodium chloride during exposure to 80 keV electrons. The irradiation kinetics were measured for electron doses up to 104 C m−2 and for dose rates up to 10 mA m−2. The energy‐loss technique is discussed in relation to other methods for assessing radiation damage.
Improved handling of structural fragile cell‐biological specimens during electron microscopic preparation by the exchange method
Authors: Peters Klaus‐Rüdiger
Published: August 2011

An exact method of preparation of soft biological specimens for electron microscopic analysis of surface fine structures is described. It allows routine preparations of fragile specimens for SEM and TEM imaging modes. With this procedure physical preparation parameters such as mechanical loads on the specimen surface or changes of temperature are controlled. The wet specimens are premounted in cheap disposable BEEM‐containers or glass boats and are constantly kept under liquid in a closed system. The exchange of preparation media is performed continuously and, if necessary, over gradients. For comparative investigations with different EM‐modes, at each step of the procedure parts of the specimens may be removed for individual processing. Conventionally prepared critical‐point dried specimens are compared to those processed by the exchange technique and preservation of surface fine structures is demonstrated. Shadow‐casted clathrin cages and stereo‐replicas of virus infected cell cultures are shown in TEM preparations. For SEM, coverslip cell cultures and isolated glomerulus basement membranes are prepared and an additional flat embedding for TEM ultrathin sections is demonstrated.
The construction of a closed‐chambered incubator for use in such techniques as enzyme and immunoperoxidase histochemistry
Authors: Nusbickel Fred R.
Published: August 2011

Many histochemical procedures, in an attempt to be as variable‐free as possible, often require such a quantity of incubation solution that there is a resulting waste of expensive chemical substrates, coupling salts, antigens, etc. More economic procedures are justifiably ignored in histochemical studies because of their uncontrollable variables. However, the variables associated with one such economic procedure (the drop method) can now be eliminated by utilizing the closed‐chambered incubator described in this paper. Slides containing tissue sections incubated in this apparatus need only 1 ml of incubation medium per slide to achieve a similar reaction product as tissue sections emersed in Coplin jars of medium. This incubator incorporates a water‐bath circulator to heat and circulate water below a shelf containing the tissue sections. Within 0·5 h, the entire incubating chamber is saturated with a 310 K water vapour. The water vapour eliminates the primary variable of the drop method incubation, evaporation of the medium. This paper describes the construction of the incubator, its evaluation, the savings obtained from one simple histochemical procedure and its applicability in enzyme and the immunoperoxidase histochemical techniques.
Freeze‐fracture autoradiography of the red blood cell plasma membrane
Authors: Nermut M.V. , Williams L. D.
Published: August 2011

A procedure for electron microscope autoradiography of red blood cell ghosts or their outer membrane leaflets is described: sheep erythrocytes, attached to positively charged mica, were either lysed and air‐dried, or freeze‐fractured ‘by hand’ and freeze‐dried. This was followed by shadowing and carbon replication; coating with photographic emulsion; exposure in darkness at 277 K; developing and fixation; carbon coating; floating off the mica and mounting on grids. Erythrocytes iodinated with 125I using the lactoperoxidase reaction were used as a test object. The efficiency of the procedure was found to be between 3·4% and 5·6%.
A simply constructed heating stage for the scanning electron microscope
Authors: Cohen Judith M. , Hartley Kenneth J. , Waldron Malcolm B.
Published: August 2011

An easily constructed heating stage has been designed for a Cambridge Scientific Instruments' Stereoscan Scanning Electron Microscope. This heating stage is capable of reaching temperatures of at least 1273 K. The stage is a simple design which can easily be built from non‐magnetic stainless steel and a natural stone consisting mainly of pyrophyllite. All heat shielding is made from these materials without the need for any liquid coolant surrounding the stage. The use of this heating stage as an instrument for the study of morphological changes during heating processes up to 1273 K is described briefly.
An improved air‐stream incubator for use in high resolution time‐lapse cinemicrography
Authors: Arro Erik
Published: August 2011

In time‐lapse microscopy of in vitro cultivated cells it is important to keep the cells and the microscope at a stable temperature. With a conventional relay controlled air‐stream incubator the periodical fluctuations in temperature will cause a focal plane oscillation due to size variations in the cell chamber and objective lens, thus making it impossible to work at high magnifications. By substituting a TRIAC‐controlled system such fluctuations can be avoided, making high‐resolution microscopy much easier.
Comparison of hollow cone and axial bright field electron microscope imaging techniques
Authors: Freeman L. A. , Howi A. , Mistry A. B.
Published: August 2011

The use of hollow cone illumination in improving the contrast transfer in bright field high resolution electron micrographs is investigated experimentally. Analysis of the results on an optical bench indicates that, although the contrast transfer is free of sign reversals, the contrast is reduced by a factor of up to 3ṁ3 in relation to axial bright field imaging. This constitutes a severe limitation to the usefulness of the hollow cone bright field technique, particularly in situations where the signal to noise level is already poor, as in high resolution imaging of non‐crystalline specimens. Factors governing the contrast in hollow cone illumination are discussed.
Observations on the structure of amorphous arsenic by high resolution electron microscopy
Authors: Stobbs W. M. , Smith David J.
Published: August 2011

Results are presented of a preliminary investigation of the structure of sputtered films of amorphous arsenic, using both high resolution bright field and tilted illumination dark field imaging modes. It is demonstrated that the material is not microcrystalline but appears to show a different form of short range order than is seen in films of amorphous carbon or germanium. The low angle scattering for the thin films was found to be very variable and it is suggested that this is associated with variability of a ‘cavern‐like’ structure and of the normal triple coordination.
Observations on the ageing of the metallic glass Fe80B20
Authors: Greer A. L. , Stobbs W. M. , Leake J. A.
Published: August 2011

The commercial binary metallic glass, Fe80B20, was examined using transmission electron microscopy after a variety of ageing treatments. While the material was found to be susceptible to beam‐induced oxidation, some tendency to crystallization at temperatures as low as 523 K was observed. Morphologically this was different from the essentially eutectic crystallization behaviour previously observed at 573 K and above.
High resolution electron microscopy of some carbonaceous materials
Authors: Iijima Sumio
Published: August 2011

The image contrast of extremely thin films of amorphous carbonaceous materials has been studied experimentally using thin supporting films of single crystal graphite. The use of thin specimens reduces the ‘overlap’ effect in imaging amorphous materials. Image contrast of their images was therefore interpreted by the ‘projected potential approximation’.

Single sheets of graphitic carbon crystal were imaged with c perpendicular to the beam and their image details were compared with those of the amorphous carbon films. This comparison demonstrated that amorphous carbon films prepared by evaporation contained microcrystalline regions having graphitic structure.
The application of dark‐field electron microscopy to the study of short‐range order in alloys
Authors: Chevalier J. P.
Published: August 2011

Through the comparison of electron diffraction and high resolution dark‐field imaging from two ‘model’ short‐range ordered alloys (quenched CuPt and quenched Ni4Mo) the different nature of short‐range order in these systems is made apparent. Dark‐field stereo microscopy is used to overcome the difficulties due to the projection of the local atomic arrangement, through the foil thickness, on to a plane perpendicular to the electron beam. It is thus possible to distinguish between three‐dimensionally bound scattering regions (called microdomains, when they are associated with a crystal superstructure and have a physically realistic size) and other scattering regions, apparently due to the superposition of scattering from several locally correlated groups of atoms. In this way and through the comparison of other dark‐field images it has been shown that local ordering in CuPt is of the form of microdomains of size 0ṁ7–10 nm, with an imperfectly ordered L ***11 structure, whilst a more appropriate description of short range order for Ni4Mo is that of static concentration wave packets. The results obtained on other short‐range ordered alloys are reviewed in the light of this application.
Microspectrophotometric studies of Romanowsky stained blood cells
Authors: Galbraith William , Marshall PaulN. , Bacus JamesW.
Published: August 2011

This paper describes a microspectrophotometric study of blood smears stained by a simple, standardized Romanowsky technique, using only the dyes azure B and eosin. Absorbance spectra are presented for twenty‐two classes of cellular object, and for the two dyes in solution, together with tabulations of spectral maxima, and suitable wavelengths for use in automated image processing. The colours of objects stained with azure B/eosin are discussed in terms of absorbance spectra. By a spectral subtraction technique, it is shown that the differential colouration of various cell structures may be explained satisfactorily in terms of the varying proportions of only four dye components. These are the monomers and dimers of azure B and eosin. Polymerization was found to occur both in solution and on binding to biopolymers. A similar analysis of a conventional Romanowsky stain would present much greater difficulties, due to the greater number of dye components, which, however, contribute little to the colours observed.
A microdensitometric method for the analysis of staining kinetics
Authors: Goldstein D. J.
Published: August 2011

The rate of histological staining is in general controlled by diffusion of dye in the dyebath and/or substrate. Microdensitometric and mathematical methods for studying the rate of staining are described, and illustrated by experiments on the staining of pancreatic cytoplasmic RNA and nuclei in sections by Azure at pH 4. Under given conditions the [half‐staining time, t1/2, of RNA was about twice that of nuclei, reflecting differences in permeability or porosity. Half‐staining times were approximately doubled if the concentration of dye in the bath was reduced by 75%, suggesting that staining is not a simple first‐order process; one possible explanation for this is that rate is affected by dye diffusion both in the dyebath and in the substrate.

Lowering the temperature from 298 K to 277 K increased t1/2for RNA about eightfold; the activation energy E of staining was therefore approximately 68 kJ mol−1.

Assuming the substrate to consist either of plane sheets of thickness b, or uniform cylinders of radius r, equations originally proposed by Crank were applied to rate‐of‐dyeing data to calculate D/b2 and D/r2, where D is the diffusion coefficient of dye inside the substrate. From the observation that D/b2 and D/r2 decreased markedly during the staining process it was concluded that both substrates studied were heterogeneous.
Mechanisms of the Feulgen acid hydrolysis
Authors: Kjellstrand Per
Published: August 2011

Our present knowledge of the two main reactions responsible for the form of the Feulgen hydrolysis curve is summarized. A suggestion that hydrolysis slightly above room temperature and in 5 M HCl is preferable is made and discussed. A formula making it possible to calculate the appropriate hydrolysis time at any normally used acid concentration and temperature is presented.
Specific techniques for the identification of O‐acylated sialic acids in colonic mucins
Authors: Culling C. F. A. , Reid P. E.
Published: August 2011

The development of methodology for the histochemistry of mucins based upon their PAS reactivity is discussed in terms of mechanism, specificity and application.

Two new histochemical methods (PB/KOH/PAS and PAT/KOH/PAS), supplemented by a variety of new and standard histochemical techniques, and correlated by parallel chemical studies, were used to demonstrate and identify C4 and side chain O‐acylated sialic acids in colonic epithelial mucins.

The application of these methods in the field of histopathology is discussed.
On the estimation of particle number
Authors: Orive Luis‐M. Cruz
Published: August 2011

Two methods are proposed for estimating the number of separated particles within a solid structure per unit volume of structure, Nv. Apart from being arranged with independence of any size parameter, no special assumptions upon the size, shape and orientation of the particles are made. The first method is based on the identity NV = (NA)u ṁ μu−1, where (NA)u is the mean number of particle sections per unit area of a plane probe Tu which is uniform random within the structure and perpendicular to a given direction u, whereas μu is the mean particle caliper length along u. The second method uses NV = AAṁV−1, where AA is the mean areal fraction of the particles per unit area of section, whereas v is the mean particle volume. The estimation of (NA)u, μu, and v requires the examination of parallel serial sections above and below Tu. Particle model reconstructions are not needed, however. Previous approaches to the problem are discussed.
Application of interferometry in quantitative histoenzymatic investigations
Authors: Gawlik Zbigniew , Wiśniewska Irmina Elżbieta
Published: August 2011

The interferometric technique has been used to measure the alkaline phosphatase activity in the kidney and small intestine. The effect of post‐mortem autolysis on the activity of this enzyme was checked in specimens taken from five normal rabbits. The results were entirely reproducible. The limitations of the method are discussed and the possible sources of error analysed.
An improved direct intermicroscopic (LM→SEM‐→TEM) correlative procedure for the examination of mammalian skeletal muscle
Authors: Vriend R. A. , Geissinger H. D.
Published: August 2011

The procedure for direct intermicroscopic (LM→SEM→TEM) correlation of muscle was modified. The major modification was the use of cryostat sections which showed far better ultrastructural preservation than did paraffin sections. The use of an osmium‐thiocarbohydrazide ligand binding procedure (OTOTO) did not noticeably improve the scanning electron microscopic (SEM) image, but did result in a subsequent transmission electron microscopic (TEM) image which showed increased contrast of the intracellular membranous components. Besides improving the preservation at the TEM level of examination, the techniques used to locate the same structure or area previously examined under the complementary modes of microscopy (i.e. LM and SEM), were also refined.
Dimensional changes of cultured smooth muscle cells due to preparatory processes for transmission electron microscopy
Authors: Lee R. M. K. W. , Garfield R. E. , Forrest J. B. , Daniel E. E.
Published: August 2011

The change in volume of cultured smooth muscle cells prepared with four different fixation procedures for transmission electron microscopy was studied. Although the cells showed swelling after being embedded in Spurr's embedding medium, the degree of swelling depended on the particular method of fixation procedure used. When the volume of the cells measured using transmission electron microscopy was compared with that of the fresh cell volume, cells prepared by two of the methods showed swelling, and cellular shrinkage was noted in the other two methods. One method which caused the least amount of volume change is recommended for quantitative electron microscopic study of vertebrate smooth muscle cell systems.
A novel device for the direct recording of diffractograms
Authors: Freeman L. A.
Published: August 2011

A device for directly recording optical diffractograms is described, and its operation and construction outlined. Consisting basically of a detector which is scanned across the optical diffraction pattern, its advantages of speed, linearity and ease of use are demonstrated.
A method for obtaining cryo‐ultramicrotome sections of 35 nm thickness monitored by myofibrillar fine structure
Authors: Tsuji S.
Published: August 2011

A method for obtaining ultrathin frozen sections of 35 nm thickness with mechanical advancing type of cryo‐ultramicrotome is proposed. The monitoring of thickness is by means of myofibrillar fine structure.
A real‐time optical image projection system for electron microscopy
Authors: Spence J. C. H. , Bleha W. P.
Published: August 2011

The Hughes liquid crystal light valve has been coupled to a transmission electron microscope using a fibre optics plate and transmission phosphor. This system makes it possible to reconstruct in real time, electron images in coherent or incoherent light of arbitrary intensity outside the vacuum. The experimental results reported are used to estimate the design parameters of an on‐line coherent optical diffractometer for high resolution work.
Computer simulation of electron microscope images on 35 mm film
Authors: Millward G. R.
Published: August 2011

A technique is described for utilizing the 35 mm microfilm plotting facilities, available at some large computer centres, as a means of portraying calculated electron microscope images. Examples related to images of single layers of carbon are given.
Electron microscopy applied to studies of the biological significance of defects in crocidolite asbestos
Authors: Crawford D.
Published: August 2011

Transmission electron microscopy is used in an investigation of crocidolite asbestos associated with two biological systems. Control material is extremely defective and contains in particular an abundance of Wadsley defects, (100) planar faults, and pores. Fibres sectioned in lung tissue and fibres taken from in vitro exposure to blood serum show evidence of erosion by two mechanisms—preferential attack at (100) planar defects and general surface dissolution.
Acoustic microscopy of human metaphase chromosomes
Authors: Rugar D. , Heiserman J. , Minden S. , Quate C. F.
Published: August 2011

Acoustic micrographs of human metaphase chromosomes have been recorded with wavelengths as short as 470 nm using liquid argon near 85 K as the acoustic wave coupling medium. Chromosomes prepared by trypsin‐Giemsa staining exhibit acoustic banding patterns similar to the G‐bands seen in optical images. Unstained chromosomes exhibit acoustic markings that do not correspond to traditional banding patterns. The observed acoustic contrast may arise from spatial variations in chromosomal mechanical properties, or from thickness variations in the fixed chromosomes.
Recording transmitted beam current for X‐ray microanalysis in a scanning transmission electron microscope
Authors: Marshall A. T.
Published: August 2011

A method of measuring transmitted beam current stability during and between X‐ray microanalyses in a STEM is described. This facility also allows analytical artefacts due to charging, drift, contamination and mass loss to be detected during an analysis.
Discriminatory X‐ray mapping of two or more elements by a pulse stretch method
Authors: Johns I. A. , Skyring G. W.
Published: August 2011

A pulse‐stretch analyser attached to an Energy Dispersive Spectrophotometer for the simultaneous mapping of two or more elements is described. The circuit for the instrument is given and examples of variable spot‐size maps which may be generated, are shown by the distribution of Si, Ti and Cr in polished grains of ilmenite, garnet, spinel and clinopyroxine.
A simple aid in the evaluation of glass knives
Authors: Franchi L. L. , Symons D.
Published: August 2011

This report describes a compact, portable, self‐contained light‐box for the qualitative inspection of glass knives under a microscope. It obviates the need for elaborate illumination and viewing facilities in the microtomy laboratory when the ultramicrotome is not itself equipped with knife‐inspection devices.
A simple method for removing stain precipitates from biological sections for transmission electron microscopy
Authors: Kuo John
Published: August 2011

Stain precipitates originating from either lead salt or double staining with uranyl acetate and lead citrate on ultrathin sections of biological material can be removed by using 10% aqueous glacial acetic acid.
The theory of the direct‐view confocal microscope
Authors: Sheppard C. J. R. , Wilson T.
Published: August 2011

A theory is presented which describes imaging in both conventional and scanning microscopes. This theory embraces conventional microscopes with partially coherent source and scanning microscopes with partially coherent effective source and detector, including confocal microscopes.

The theory is applicable to the direct‐view confocal microscope of Petrán̂, the design of which is discussed. This microscope combines the resolution and depth discrimination improvements of confocal microscopy with the ease of operation of the conventional microscope.
Isolated heart myocytes: ultrastructural case study technique
Authors: Robinson Thomas F. , Hayward Barbara S. , Krueger John W. , Sonnenblick Edmund H. , Wittenberg Beatrice A.
Published: August 2011

We have developed a method for performing case studies of heart muscle cells enzymatically isolated from the ventricular walls of rats that is a simple and inexpensive adaptation of procedures developed for the examination of monolayers of attached, cultured cells. The technique represents a marked departure from published accounts of electron microscopic studies of pellets or monolayers from a population of potentially heterogeneous isolated myocytes. Here we report the method, which we have used under controlled conditions with 0 mmol and 1 mmol added CaCl2, to correlate sarcomere length and electrical stimulatibility in the living state with ultrastructural features that include the relative disposition of myofilaments and the integrity of the cell coat. The degree of shrinkage during the preparative steps is less than 5%, as directly determined from photographs of striations in the living, fixed, and embedded states.
Specimen heating during sputter‐coating
Authors: Robards A. W. , Wilson A. J. , Crosby P.
Published: August 2011

It is possible to sputter thin films of gold on to surfaces of frozen biological specimens at very low temperatures (< 120 K) without untoward effects from heating. This is achieved by using permanent magnets to confine the plasma and thus to minimize the energy required to give a reasonable sputtering yield. The system described uses only 250 V at 12–15 mA to give 15 nm films within 2–3 min. It is shown, from theory portraying ‘worst‐case’ conditions, that the specimen temperature could not increase by more than 6.0 K at equilibrium. Practical results support the theoretical assumptions. Similar considerations have been applied to sputtering at normal ambient temperature where it is shown that appropriate design of simple apparatus and selection of operational conditions can give adequate films in a reasonable time with negligible (< 3 K) temperature rise above the starting temperature.
Continuous recording of microvascular dimensions with a rotating mirror microscope
Authors: Hara Akira
Published: August 2011

A system which permits continuous recording of the dimensions of microscopic blood vessels is described. The system uses a combination of a rotating mirror and a pinhole aperture with a microscope to scan microvessel image signals at a rate of one per second. Image signals from the gate circuit are converted to digital signals; further conversion to analogue signals is obtained by integrating the digital signals. The analogue voltages are proportional to the vessel dimensions. A linear relationship was observed over a range of 20–200 μm (standard deviation ±3.0%). The contrast between vessels and surrounding tissue is amplified by using a B‐12 optical filter. By using this system, the mesenteric arteriole was observed after reaction with adrenaline and noradrenaline in rats. The contractile response of the arteriole to adrenaline was greater than with noradrenaline. A maximum response of 20% decrease of the vessel outer diameter is induced by 5.5 × 10−7 mmol adrenaline and 5.9 × 10−6 mmol noradrenaline.
A simple method for whole‐cell preparation in electron microscopy
Authors: Aizu Seiei , Itoh Tsunetoshi , Yamamoto Toshi Yuki
Published: August 2011

A simple method for whole‐cell preparation without using gold or platinum grids as substrata for culture is described. Cells were cultured on formvar film over round pores, each 3 mm in diameter, of Thermonox coverslips. The cells on the formvar coated coverslip are fixed, stained, dehydrated in situ, and introduced into a critical point drying apparatus. A small quantity of 0.2% mesh‐cement is applied to slot grids, and they are laid onto the formvar film over the pores of the coverslip. After the grids are removed from the plastic substratum, they are ready for observation under the electron microscope.
Effects of glutaraldehyde or osmium tetroxide fixation on the osmotic properties of lung cells
Authors: Wangensteen Douglas , Bachofen Hans , Weibel Ewald R.
Published: August 2011

The osmotic properties of lung cells have been tested before and after perfusion fixation of isolated, perfused lungs with either glutaraldehyde or osmium tetroxide. The testing procedure was to add hypertonic sucrose to the perfusate for several minutes and monitor the lung weight response (an ‘osmotic transient’). Each lung was perfused with one or the other fixative solutions for 10 min, then the perfusate was changed back to Ringer‐lactate before the post‐fixation test was conducted. The results indicate that osmium tetroxide makes the cell membranes as permeable to sucrose as to water, and that sucrose thus causes no osmotic volume change. Glutaraldehyde, on the other hand, apparently preserves the impermeability of the cell membranes to sucrose, but the osmotic volume response is attenuated, indicating that significant changes in the cells have occurred.
Microspectrophotometric studies of Romanowsky stained blood cells
Authors: Marshall Paul N. , Galbraith William , Navarro Erlinda F. , Bacus James W.
Published: August 2011

This paper describes a comparison of the performance of two standardized Romanowsky blood stains, namely those of Marshall et al. and Wittekind et al., both containing azure B and eosin alone. Stain performance is assessed objectively by the use of three complementary techniques, all based on the visible absorbance spectra of stained cellular substrates. The first of these techniques is a simple comparison of the shapes and heights of the absorbance spectra. The second technique uses the CIE Colorimetric System, and thus permits the quantitation of colour in a manner that agrees with human observation. CIE co‐ordinates (chromaticity points, luminance) are calculated directly from absorbance spectra. The third technique is that of spectral subtraction, which yields a set of factors which describe the quantities of component dyes which are bound by the object. This technique, unlike the other two, requires a priori knowledge of the dyes used in the stains, and their spectra when bound to cellular substrates.

Although the differences between the two methods are subtle, and hard for the subjective observer to define, the objective methods described here do show statistically significant differences. Wittekind's stain produces less intense staining, except for lymphocyte and monocyte cytoplasms. To the human eye, the differential coloration of these two substrates is more pronounced, but the difference between all nuclei and cytoplasms is less marked. The major difference in the uptake of dye components is in the small quantities of eosin dimer that are bound in this technique.
Interspersion of phases in a material
Authors: Davy Pamela
Published: August 2011

A 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.
Measuring error and sampling variation in stereology: comparison of the efficiency of various methods for planar image analysis
Authors: Mathieu Odile , Cruz‐Orive L. M. , Hoppeler H. , Weibel E. R.
Published: August 2011

An 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 as Vv, 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 obtaining Vv and Sv estimates. 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 the Vv and Sv estimates 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 of Vv in the biological sample.
Prediction of permeability of non‐woven geotextiles from morphometry analysis
Authors: Masounave J. , Rollin A. L. , Denis R.
Published: August 2011

The permeability coefficient of non‐woven geotextiles used for soil stabilization, erosion control and earth reinforcement is predicted from a proposed analytical method. A mathematical model is used to depict both fabric's void and soil particles histograms and related them to forecast eventual clogging level. Experimental data indicated a relationship between water permeability and fibre density of a fabric. Lastly a proposed method is presented for the prediction of the filtration performance of multi‐layer or composite fabrics.