bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of the polymeric cryoprotectant dextran on fluid secretion in the isolated rabbit pancreas
Authors: Kuijpers Gemma A. J. , Roomans Godfried M.
Published: August 2011

Physiological effects of the polymeric cryoprotectant dextran on an ion‐transporting epithelium were investigated. In the isolated rabbit pancreas, dextran caused inhibition of fluid secretion and an increase of the concentrations of Na+, K+ and Cl− in the secreted fluid. Dextran did not affect the basal or pancreozymin‐stimulated enzyme secretion. These effects of dextran can partially be explained by the fact that it is osmotically active and does not permeate through the epithelium. The effect of dextran on water transport can be compensated by lowering the ion concentrations in the solvent of the cryoprotectant. It is concluded that in cryoprotected ion‐transporting epithelia the absolute ion concentration values obtained by X‐ray microanalysis of frozen‐hydrated specimens may not be completely correct, but that valid conclusions about intracellular ion distribution may still be drawn.
A method for studying the three‐dimensional organization of cytoskeletal elements of cells: improvements in the polyethylene glycol technique
Authors: Nagele R. G. , Roisen F. J. , Lee H.
Published: August 2011

A method utilizing polyethylene glycol (PEG) as an extractable embedment for electron microscopy is described. Tissues are fixed according to conventional protocols, embedded in PEG, and sectioned. Sections (ranging from 100 to 500 nm in thickness) are mounted on grids, divested of their PEG matrix, critical‐point‐dried, and examined stereoscopically. This method greatly facilitates studies on the three‐dimensional organization of cytoskeletal and cytoplasmic contractile systems in both muscle and nonmuscle cells.
Combined flow cytometry and image cytometry of the same cytological sample
Authors: Tanke H. J. , van Driel‐Kulker A. M. J. , Cornelisse C. J. , Ploem J. S.
Published: August 2011

Flow cytometry and image cytometry, two measuring techniques in the field of analytical cytology, can be used sequentially on the same cytological sample. Cells stained with a fluorochrome for the determination of for example, DNA or RNA content are first analysed in suspension by flow cytometry. The results of the fluorescence analysis of the individual cells are presented after data processing as frequency histograms of the DNA or RNA content of all the cells of the sample. In these histograms certain cell populations such as those with an increased DNA content are defined and these are then selected for further investigation. This is achieved by sorting cells of interest into centrifugation buckets by means of electrostatic deflection of the droplets containing such cells. Sorted cell populations are then centrifuged on to glass slides and stained according to the acriflavine Feulgen–SITS staining procedure, a quantitative method for DNA and protein. Image cytometry of these stained cells is performed with a computer controlled television based image analysis system (LEYTAS). With this system abnormal cells with elevated DNA content or increased chromatin contrast are automatically detected, thereby eliminating almost all artefacts and normal cells. Subsequently detected objects are stored in grey‐value memories after the automated analysis for visual examination by the cytologist.

The possibilities of combined flow cytometry and image cytometry are illustrated in typical examples in the field of cervical, bladder and mammary cytology.
Determination of the illuminating angle and defocus spread in transmission electron microscopy
Authors: Tsuji M. , Manley R. St. John
Published: August 2011

In high resolution electron microscopy the beam divergence and defocus spread are important factors determining the resolution limit of the microscope. In this paper a straightforward method is proposed to estimate the illuminating angle (beam divergence) and the parameter of defocus spread using optical diffraction patterns from a through focal series of electron micrographs of a thin amorphous film.
BSE Z contrast imaging of uranium stained pores in the avian eggshell
Authors: Silyn‐Roberts H.
Published: August 2011

A method is described for estimating the number of blocked pore channels and pore density and spatial distribution by the staining of the exterior pore openings of unobstructed pores with uranyl acetate, and identification of them using backscattered electron atomic number contrast imaging in the scanning electron microscope.
The complex‐shaped ‘perforated’ synapse, a problem in quantitative stereology of the brain
Authors: Groot Didima M. G. De , Bierman Egbertus P. B.
Published: August 2011

Failure to appreciate the consequences for stereological work of the simultaneous presence of complex‐shaped perforated and disc‐like non‐perforated synapses in brain tissue results in underestimation of synaptic profile length and overestimation of synaptic density when measured in randomly selected ultrathin E‐PTA slices. This problem can be solved by using serial slices and a calculation method which makes no assumptions about synaptic size and shape. A three‐dimensional reconstruction is unnecessary.
The study of high temperature oxidation by transmission electron microscopy
Authors: Butler E. P.
Published: August 2011

In this contribution, the experimental techniques available for the study of the high temperature oxidation of metals and alloys by transmission electron microscopy are reviewed. The important first steps of specimen preparation are briefly discussed and the unique advantages of examining thin vertical sections emphasized. A number of microscope imaging modes, both conventional and unconventional in nature, are then described, which can provide useful information about particular features of oxidation processes. Finally the contribution in situ experimentation can make in permitting direct observation of the early stages of oxidation is noted. The capabilities of the techniques are illustrated with examples from oxidation studies in Ni, Fe, Ti, Al and their alloys.
Microscopic techniques to examine structure in anisotropic cokes
Authors: Markovic V. , Marsh H.
Published: August 2011

Petroleum pitches on carbonization form anisotropic cokes. Structure in these cokes is dependent upon the method of carbonization. For example, the delayed coker can produce needle‐cokes from suitable feed‐stocks. Structure in cokes cn be studied as the optical texture of polished surfaces using optical microscopy, the optical texture being descriptive of macro‐crystallinity within the coke. These polished surfaces of cokes when studied using polarized light indicate the orientation of the constituent lamellar molecules of the macrocystallinity to the plane of the polished surface. This approach has limited application in assessments of structure in three dimensions. The study describes how the techniques of etching of polished surfaces of coke, mapped initially by optical microscopy, using a solution of chromic acid followed by examination of the same area by scanning electron microscopy, reveals structure in anisotropic cokes.
Factors which influence light microscopic visualization of biological material in sections prepared for electron microscopy
Authors: Rieder Conly L. , Bowser Samuel S.
Published: August 2011

Epoxy‐embedded biological material, sectioned for conventional or high‐voltage electron microscopy, can be visualized within the section with good contrast and detail by phase‐contrast or dark‐field light microscopy. The (phase) contrast of such material is not substantially influenced by the type of embedding resin or section support substrate. It is, however, influenced by the type of fixation, by heavy metal (uranyl and lead) staining and by the section thickness. After screening ultrathin and semithin sections for content with the light microscope, one need stain and examine only those grids containing sections of interest. This approach eliminates the need to screen sections with the electron microscope and, in some cases, the need to stain non‐useful sections. This time‐saving procedure is particularly useful for studies requiring ultrastructural examination of a selected area or structure which is large enough to be visualized with the light microscope but which comprises only a small volume of the embedded material.
Integral hologram using scanning electron micrographs: a new application of display holography
Authors: Mann Mary‐Jacque , Eisen Judith A. , Stork David G.
Published: August 2011

We produced at 43 times 23 cm, 120° integral hologram of a marine protozoan test to investigate the museum exhibit potential of interfacing scanning electron microscopy with commercially available integral holography. We describe here our procedure and some of the strengths and weaknesses of this holographic medium in exhibit situations.
Selection of calcium isotopes for secondary ion mass spectrometric analysis of biological material
Authors: Burns Margaret S.
Published: August 2011

The use of stable isotopes as tracers for elemental localization is a function of the background count rate which is dependent upon both the natural abundance and the quantity of interferences at the nominal mass. The occurrence of a variable and unpredictable high background count rate at mass 44+ in biological tissue, probably CO2+, limits the usefulness of this isotope for physiological problems.
Applications of modern microdiffraction to materials science
Authors: Carpenter R. W. , Spence J. C. H.
Published: August 2011

Modern experimental techniques for static convergent beam electron microdiffraction in transmission electron microscopes are discussed and compared to the better known selected area electron microdiffraction methods. The effects of probe coherence are qualitatively discussed. Some recent applications of convergent beam microdiffraction to microstructural characterization of small particles, various lattice defects and amorphous solids are described.
Dimensional changes of tissues in the course of processing
Authors: Iwadare TSUKASA , Mori Hidekazu , Ishiguro Katsuyuki , Takeishi Makoto
Published: August 2011

Dimensional changes of bovine kidney and liver tissues in the course of processing under four different schedules were measured. Shrinkage of tissues at dehydration, substitution with intermedium and paraffin infiltration stages was 1–2%, 2–5% and 5–10% respectively. There was no significant difference in final dimension and morphology among the specimens processed under the different schedules. Any one of the investigated schedules can be employed for practical tissue processing.

For many years, biologists' attention has been paid to swelling and shrinkage of tissues in the course of specimen preparation for microscopy. Morphometric changes of tissues throughout specimen preparation for EM were discussed by Kushida (1962) and Hansdete & Gerrits (1983). Bahr et al. (1957) precisely measured changes of volume, weight and specific gravity of several organs of guinea‐pigs during fixation and subsequent processing. Lee et al. (1980) described dimensional changes of specimens at the stages of plastic monomer infiltration and polymerization. A morphometric study from fixation through cutting of cervical tissue by Boonstra et al. (1984) appears in a current journal. Further, effects of lithium salts as additives and 2,2‐dimethoxypropane as a dehydrant on dimensional stabilization at dehydration stage were reported by Boyde & Maconnachie (1980) and Truter et al. (1979) respectively.

While there have been the above‐cited studies, it appeared of interest to investigate further dimensional changes of tissues with the passage of time at each stage of processing. As precise determination of tissue dimensions and comparison of shrinkage under various conditions seemed of importance, we have devised a rational processing schedule for optical microscopy.
Ethanol, an efficient coolant for rapid freezing of biological material
Authors: Marchese‐Ragona S. P.
Published: August 2011

Supercooled ethanol was used for freeze‐quenching protozoan samples and gave reasonable ultrastructural preservation. The use of ethanol as a coolant has considerable advantages in terms of its relative safety, high cooling efficiency and low cost when compared with other coolants currently used for freeze‐quenching.
Facility for rapid preparation of silicon and silicide TEM specimens
Authors: Kritzinger S. , Churms C. L.
Published: August 2011

A simple chemical jet polishing arrangement, for the thinning of semiconductors or metals for transmission electron microscopy (TEM), is described for the specific case of silicon and silicides. The effect of variation in three mechanical parameters on the profile and quality of the specimen is described, and the optimum conditions are determined. A proposed polishing solution is one part 48% HF mixed with one part fuming HNO3. Reproducibility is only achieved in the presence of a relatively large concentration of nitrous acid in the polishing solution. The solution must also be relatively concentrated, as the reaction rate falls off rapidly with decreasing concentration.
Scanning electron microscopy of Vicia faba nuclei structure
Authors: Polakowski I. J. , Macewicz J. B.
Published: August 2011

Using a simple and fast technique, chromosomes and nuclei of V. faba were isolated and examined under various magnifications with SEM. Details of chromatin construction were observed.
Electron microscope study of surface topography by geometrical determination of metric characteristics of surface elements
Authors: Simov S. , Simova E. , Davidkov B.
Published: August 2011

Three micrographs made at different tilting angles are necessary to determine the spatial coordinates of each point from the surface of micro‐object. The x′ and y′ coordinates of the points are measured in an arbitrary coordinate system O'X′Y′ which ensures convenience in measurements. The coordinates measured are transformed into a main coordinate system OXYZ related to the microscope and the image plane. The z coordinates are calculated. The coordinates of the points are used to solve the following metric problems by applying analytical geometry: computation of (1) distances (between: two points, a point and a straight line, a point and a plane), (2) angles (between: two straight lines, a straight line and a plane, two planes), (3) area of a triangle and (4) volume of a body, which may devided into tetrahedra. A computer program for solving the above problems is written in BASIC.
Very low voltage sputter coating
Authors: Echlin Patrick , Gee Wilf , Chapman Brian
Published: August 2011

Very low voltage sputter coating, in the range 175–300 V, has been used to produce finely structured thin films of noble and refractory metals for use in high resolution scanning electron microscopy. There is a marked diminution in the particle size with a decrease in cathode voltage. Although the sputtering times are longer than with conventional diode sputter coating, such times are shorter than those required to produce similar films by Penning or ion‐beam sputtering. The refractory metals produce films which are fine grained and suitable for high resolution studies. The method has been used to sputter coat thin layers of aluminium. All attempts at sputtering carbon have failed; the reasons for this are discussed in some detail.
A modified cleansing procedure to obtain large freeze‐fracture replicas
Authors: Mazière Ann M. G. L. De , Aertgeerts Philip , Scheuermann Dietrich W.
Published: August 2011

A method for cleaning freeze‐fracture replicas is elaborated which avoids their rolling up and fragmentating during successive steps. Immediately after freeze‐fracturing, the replicated tissue is slowly thawed from 77 K to room temperature on solid methanol. Safe passage through the subsequent cleaning steps is facilitated by using solutions of gradually increasing surface tension. After at least 24 h of fixation in methanol, the tissue is digested in half‐strength bleach containing 5% ethanol. Following further cleaning in full‐strength bleach, the remaining organic material attached to the replica is dissolved overnight at room temperature in 50% saturated sodium hydroxide.
A technique for revealing tissue embedded within resin blocks
Authors: Wang X.‐D. , Canny M. J.
Published: August 2011

A technique is described for revealing in fine detail large pieces of tissue still embedded within rough, scratched or partly‐trimmed blocks of epoxy and other resin before sectioning. The pieces of tissue immersed in baths of oil or glycerol and illuminated by an appropriate optical system, may be photographed to provide a guide to subsequent sectioning, aiding the precise location of elements in the sections back to their position in the parent tissue, and for tracing the connections of the element between serial sections. The method has been used by the authors in sectioning for light microscopy, but could equally be used with sections for electron microscopy.
Reflection X‐ray microscopy
Authors: Franks A. , Stedman M.
Published: August 2011

X‐ray microscopy has an important role to play both in microstructural studies of materials and in the examination of high temperature plasmas. Reflection microscopy offers some advantages over other types of X‐ray microscopy in the range of wavelengths which can be employed, in its potential for absorption analysis and in the ultimate resolution of about 10 nm, which may be achieved in favourable circumstances. In the first of a series of microscopes now under development, submicrometre resolution has been achieved at a wavelength of 0.8 nm.
Progress in multilayer devices as X‐ray optical elements
Authors: Dhez P.
Published: August 2011

A new kind of mirror based on multilayering techniques gives the possibility of preparing artificial Bragg reflectors over all the X‐UV range. The possibility to choose most of the parameters governing the reflectivity opens the possibility to get a very good efficiency, even under normal incidence. Main parameters, evaporating techniques and tests are described. Some example of recent results are compared to the theoretical predictions.
Some theoretical aspects of type‐1 magnetic contrast in the scanning electron microscope
Authors: Wells Oliver C.
Published: August 2011

Type‐1 magnetic contrast can be obtained in the secondary electron (SE) image in the SEM from a sample having an external magnetic field if the SE detector is directionally sensitive. Gauss' theorem is applied to show that the normal component of induction at the surface of the sample can be calculated from the measured spatial derivative(s) of the SE difference‐signal. A method is given in this paper for calculating the three components of the induction in the entire volume above the sample surface. Reasons are given for believing that type‐1 magnetic contrast is limited in spatial resolution by the fluxon unit.
A simple re‐embedding method for the preparation of testicular cell cultures for light and electron microscopy
Authors: Jones Huw Bowen , Gray Tim J. B.
Published: August 2011

A simple and reproducible method is described for the preparation of cell cultures for light and transmission electron microscopy. Mixed testicular cells are grown on collagen layered, PTFE‐coated coverslips. Thin sheets of plastic‐embedded cells are packed together and re‐embedded permitting the examination of sections cut perpendicular to the plane of the culture and, thus, the intercellular relationships at different levels throughout the culture.
Recrystallization and ice‐crystal growth in a biological specimen, as shown by a simple freeze substitution method
Authors: Steinbrecht R. A.
Published: August 2011

The sensory hairs of the silkmoth, Bombyx mori, are suitable test objects to check for recrystallization and secondary freezing damage in a biological object, because cryofixation by immersion into propane (90 K) routinely yields well‐preserved specimens without noticeable freezing damage. After rewarming the frozen specimens for 10 min to 230 K (boiling propane), the tissue preservation has not deteriorated, and even after 45 min at 230 K, ice‐crystal ghosts rarely exceed 50 nm. Two minutes at 250 K (in deep freezer) produced moderate freezing damage with ice‐crystal ghosts of 30–75 nm, whereas 90 min at 250 K resulted in severe damage with ice‐crystal ghosts well over 100 nm. Secondary freezing damage by ice‐crystal growth upon rewarming well‐frozen biological specimens, therefore, is a relatively slow process, depending not only on the temperature, but also on the exposure time. Moreover, with some biological specimens, secondary ice‐crystal growth starts at much higher temperatures than previously guessed, and with short exposure times rarely should become a hazard in fine structure work.
Contrast of biological cryosections in scanning transmission electron microscopy
Authors: Zierold Karl
Published: August 2011

Ultrathin (70–100 nm thick) frozen‐hydrated cryosections of yeast cells were studied by scanning transmission electron microscopy (STEM). Generally, the contrast is very poor in brightfield and increases slightly by use of the darkfield signal in imaging. The contrast can either be enhanced by selective staining before cryofixation or by mass loss caused either by freeze‐drying or by radiation damage. Partial freeze‐drying by superficial ice sublimation seems to be the most efficient method to increase the contrast in cryosections in the frozen‐hydrated state. The highest contrast in cryosections is achieved after complete freeze‐drying.
Immunocytochemical demonstrations of cytoplasmic and cell‐surface EGF receptors in A431 cells using cryo‐ultramicrotomy, surface replication, freeze‐etching and label fracture
Authors: Boonstra J. , van Belzen N. , van Maurik P. , Hage W. J. , Blok F. J. , Wiegant F. A. C. , Verkleij A. J.
Published: August 2011

In this paper we describe the use of a number of complimentary methods to visualize cytoplasmic and cell‐surface located epidermal growth factor (EGF) receptors in cultured A431 cells. Cryo‐ultramicrotomy in combination with immuno‐gold labelling will be shown to provide an excellent method in visualizing cytoplasmic located EGF receptors in addition to cell‐surface located EGF receptors. An important aspect in this method involves the possible effects of the fixatives on antigenicity. Using radioactive labelled anti EGF receptor antibodies, it was shown that formaldehyde as a fixative had no significant effect on label‐efficiency.

The density and lateral distribution of EGF receptors at the cell surface has been studied by three methods, i.e. surface replication, freeze etching and label fracture, all methods in conjunction with immuno‐gold labelling. These methods allow in principle a quantitation of the surface distribution of the EGF receptors. The surface‐replication method involves, however, dehydration and critical‐point drying steps, and using radioactive labelled anti EGF receptor antibodies it was shown that in particular OsO4 fixation and dehydration caused a significant loss of cell‐associated antibodies. This disadvantage is overcome by freeze etching and the label‐fracture method, and as such these techniques provide the best methods for quantitative analysis of the planar distribution of cell‐surface located EGF‐receptors.
Normarski differential interference microscopy study of the ferroelastic domains in NaCN, RbCN and KCN
Authors: Gash Philip , Lüty Fritz
Published: August 2011

Photomicrographs of the ferroelastic domains present in the low temperature, intermediate phase of NaCN, RbCN and KCN are presented with their linear dimensions and angular orientations. The Normarski optical technique used to display the domain surfaces in colour and used to determine the small out‐of‐plane angular orientations is discussed in detail. Figures and the construction details are presented of the cold stage that allowed microscopic examination of the crystal surfaces by either reflected or transmitted light down to liquid nitrogen temperatures.
The effect of subsurface topography on secondary electron images from chromate pretreated aluminium surfaces
Authors: Treverton J. A. , Amor M. P.
Published: August 2011

In secondary and scanning transmission electron microscopes, secondary electron images of surface films can be dominated by an image derived from electrons back‐scattered from the interface between the film and the substrate. The extent of the domination has been established by studying the variation in image obtained using primary beams of different energy and by platinum coating to enhance surface secondary electron emission.

Studies of thicker films also established that chemical or structural difference within a film also lead to imaging effects. In general, 5 keV electrons are the most effective in producing subsurface and structural or chemical imaging effects.
The suitability of various adhesives as mounting media for scanning electron microscopy. II. General purpose glues
Authors: Witcomb M. J.
Published: August 2011

The results presented in this paper complement those on epoxies, sprays and tapes reported in Witcomb (1981). One hundred and thirteen relatively commonly used general purpose glues or made‐up solutions have been tested with respect to possible application as scanning electron microscope specimen mounting adhesives. Recommendations are made as to the most appropriate adhesives to use.
Fast cryofixation technique for X‐ray microanalysis
Authors: Zglinicki Thomas von , Rimmler Martina , Purz Hans‐Joachim
Published: August 2011

The proposed cryofixation technique uses a tubule‐shaped needle chilled in liquid propane for simultaneous excision and freezing of a tissue specimen. Due to this simultaneity, ionic shifts created by traumatic influences are avoided even in the outermost cells of the specimen.

Moreover, it is shown here that stopping the blood flow for more than about 10 s results in notable ionic shifts between cells and extracellular space in rat heart and liver. Such preparative ischaemic injury is minimized by the Fast Cryofixation Technique because it can be easily performed on organs within the circulatory system, whilst the heart of the animal is still beating.

Intracellular concentrations of the monovalent ions in rat heart and liver, obtained by this method, tally well with recent results from different independent techniques reported in the literature.

As demonstrated by cross‐sectioning and freeze‐fracturing, the structural preservation of the freezing technique is sufficient for X‐ray microanalytical work.
Raster images and measurement with a Vickers M86 scanning microdensitometer and interferometer by computer control
Authors: te Meerman G. J. , Anders G. J. P. A. , Wierda J.
Published: August 2011

A simple and easily adaptable interface between a Vickers M86 scanning microdensitometer and microinterferometer and a Z80 CP/M based microcomputer (Zenith Z89) is described. The hardware is supplemented by a software package written in Fortran‐66, linked with an assembly routine for two‐dimensional spot control and measurement. Facilities are provided for background correction, image processing, calibration of the spot movement, correction for glare, diffraction and finite spotsize and computer‐aided focusing. Results can be plotted on a matrix printer and on a graphical unit as ruled surface plot, as isophase or isodensity contour diagram or in three‐dimensional projection with hidden line removal.
Steric hindrance in immunolabelling
Authors: Voorhout W. F. , Leunissen‐Bijvelt J. J. M. , Leunissen J. L. M. , Verkleij A. J.
Published: August 2011

In this paper we describe immunocytochemical detection of PhoE pore protein in the outer membrane of E. coli K‐12 cells in dependence of a variety of labelling approaches.

Immuno‐gold labelling on ultrathin cryosections showed a uniform, dense labelling of the outer membrane of all cells. However, using immunofluorescence, whole‐mount or freeze‐etch labelling methods, labelling was limited to less than 5% of the cell population.

In order to understand this phenomenon, immunoincubated cells exhibiting less than 5% labelling were processed for cryo‐ultramicrotomy. Reincubation of the sections with antibody and probe resulted in labelling of all of the cells.

If an E. coli Gal‐U mutant strain, defective in the lipopolysaccharide (LPS) carbohydrate chain length, was used, each approach rendered 100% labelling.

From these results it is concluded that the antigenic sites of the PhoE pore protein are not accessible in intact ‘wild‐type’ cells due to steric hindrance caused by the LPS carbohydrate chains. In cryosections this steric hindrance is partly precluded since antigenic determinants are exposed at the section surface in transversely cut membranes.

Our results emphasize the necessity to compare results obtained by means of several, basically different approaches.
High resolution electron microscopy of partial dislocations in the Laves phase structure
Authors: Kitano Y. , Takata M. , Komura Y.
Published: August 2011

A Mg‐base Laves phase was investigated by high resolution electron microscopy (HREM). Linear defects found at terminations of stacking faults were classified into three groups. The first is a partial dislocation at a termination of a stacking fault, the second is a superposed partial dislocation which is defined as a defect produced by a superposition of terminations of two or more stacking faults lying on neighbouring layers, and the third is a combined linear defect which consists of a characteristic combination of terminations of stacking faults. In the last case the total stacking fault vector becomes equal to the translation vector in the basal plane, so that the defect needs no relaxation of the lattice. The Burgers vectors of the partial dislocations were estimated with the aid of modified Burgers circuits.
The use of gold markers in immunocytochemical studies of microbiological organisms: a review
Authors: Beesley Julian E.
Published: August 2011

Colloidal gold probes have revolutionized electron immunocytochemistry and are now used extensively for microbiological studies. The gold probes can be applied in one of several methods to gain valuable information from the sample. The pre‐embedding technique, the post‐embedding technique, the immunonegative stain technique, the immunoreplica technique and the immunofreeze‐fracture technique, are each described and their applications in microbiology, for diagnosis, for the detection of the site of antigen synthesis in host cells, for vaccine production and for genetic engineering are reported.
A rapid and simple technique for correlating light microscopy, transmission and scanning electron microscopy of fixed tissues in Epon blocks
Authors: Cajander Stefan B.
Published: August 2011

summary

A simplified and standardized technique for close correlation between light microscopy (LM), transmission electron microscopy (TEM) and scanning electron microscopy (SEM) is described. Perfusion and immersion fixed tissue specimens were embedded in Epon 812 and cut for conventional LM and TEM. The Epon blocks with remaining tissue were thereafter treated with epoxy solvent (ethanol‐NaOH solution) for partial epoxy resin removal only (dissolving rate approx 33μm/h). The blocks with partially blotted tissue specimens were then critically point dried and gold coated for SEM. This method, in an easy way, allows repeated observations with LM, TEM and SEM with preserved fine structure and exact correlation. Since the technique is so simple and there is no need for special equipment the method can easily be adopted in all laboratories with basic SEM standards.
SEM low magnification stereoscopic technique for mapping surface contours: application to measurement of volume differences in human teeth due to polishing
Authors: Russ J. C. , Hare T. M. , Christensen R. P. , Hare K. T. , Russ J. C.
Published: August 2011

SEM stereogrammetry with a low magnification mosaic of pictures is used to measure the elevation of many individual points. This random array of elevations is then connected into a triangular mesh, from which a contour map of elevation is drawn for the entire surface. Maps of surfaces before and after removal of material are used to determine the volume removed. The method is applicable to many circumstances of wear, erosion or deformation of surfaces. It is applied here to the erosion of human teeth due to dental polishing.
Fluorescence reactions of orcein: new applications for an old stain
Authors: Molero M. L. , Castillo P. Del , Stockert J. C.
Published: August 2011

The fluorescence properties of orcein are described in this paper. Under suitable exciting light, acidic solutions of orcein showed emission peaks at 587 nm (low concentration) and at 620 nm (high concentration). In fluorescence microscopy an intense orange‐red emission was found in the cytoplasm and nucleoli from acetic orcein squashes of meristematic cells, as well as in the cytoplasm of Ehrlich tumour cells and in chicken erythrocyte nuclei. When semithin sections of Epon‐embedded tissues were treated with orcein, a strong fluorescence reaction (orange‐red) appeared in starch granules, cell walls, elastin, collagen, reticulin, keratohyalin, chromatin and mucin. Cytofluorometric measurements of orcein‐stained chromatin revealed an emission peak at 585 nm with a shoulder at 620 nm. These spectroscopic and microscopical results suggest the possibility of employing orcein as a fluorochrome.
Morphological optics
Authors: Serra J.
Published: August 2011

Image analysis methods are first classified into four groups of theories related to optics, after which the associate hypotheses, the structures, the laboratory equipment and the mathematical framework for one of them, better known by the term of morphological optics, are studied in detail. Conclusions are drawn as to the role played by hypotheses in image analysis.
Determination of the direction of the crystal optical axis of ground uniaxial precious stones by means of polarized‐light microscope photometry
Authors: Boguth W.
Published: August 2011

The direction of the crystal optical axis of a uniaxial microscopic object is determined on the basis of the known correlation between this direction, the displacement of isogyres of the conoscopic figure, and the rotation of the microscope stage. It is shown that the use of photoelectric equipment for indicating the displacement, a stepping motor controlled by a microprocessor for rotating the stage, and a desk calculator for processing the photometric data provides a more convenient and accurate determination than classicial procedures, involving visual inspection and manual operation. The method is particularly suitable for uniaxial crystals of the size and shape of precious stones.
On double‐refracting microinterferometers which suffer from a variable interfringe spacing across the image plane
Authors: Pluta M.
Published: August 2011

It has been stated that interference fringes are asymmetrically distributed in the image plane of some double‐refracting microinterferometers. This defect is especially produced by typical birefringent Wollaston prisms and is responsible for some errors in the measurement of optical path differences. In particular, the errors arise when the interfringe spacing is directly measured in the image plane or determined from an interferogram recorded on a photographic material.
The intracellular distribution of ions and water in rat liver and heart muscle
Authors: Zglinicki Thomas von , Bimmler Martina
Published: August 2011

Local dry mass concentrations of intracellular compartments in rat heart muscle and liver cells were estimated by quantitative electron microscopy and X‐ray microanalysis of ultrathin frozen‐dried cryosections. The results were used to calculate elemental concentrations per litre of compartment water from the X‐ray microanalytical data.

Water fractions were between 80.3 ± 1.3% of wet weight in the decondensed chromatin and only 45.1 ± 1.7% in mitochondria of liver cells. The lowest water fraction in heart muscle cells was also found in mitochondria. The ionic concentrations found in the cytoplasm of liver cells and in the myofibrils are in accord with the electroneutrality rule and in osmotic equilibrium with the extracellular concentrations. The concentrations of Na, K, Cl and P both in the cytoplasm and in the regions of decondensed chromatin within the nuclei were found to be equal.

However, in regions of condensed chromatin K+ concentrations were found to be much higher than expected for a Donnan distribution of ions free in solution. Most probably the activity coefficient for K+ is lower in the condensed chromatin than in the decondensed or in the cytoplasm. The same holds true for the A‐band as compared to the I‐band in heart muscle cells. A sequestration of K+ was measured also in the rough endoplasmic reticulum (RER) of hepatocytes. The Cl− concentration in mitochondria both in heart muscle and liver cells has been measured far in excess of what might be expected from a Nernstian distribution. A coupled inward Cl− transport in mitochondria must, therefore, be assumed.
Electron microscopy and diffraction of icosahedral and decagonal quasicrystals in aluminium‐manganese alloys
Authors: Thangaraj N. , Subbanna G. N. , Ranganathan S. , Chattopadhyay K.
Published: August 2011

Electron microscopic observations on the morphology of icosahedral and decagonal quasicrystals in aluminium‐manganese alloys have been interpreted in favour of a heterogenous nucleation mode. The transition of icosahedral quasicrystals from nonfacetted dendrites to facetted particles occurs as a function of composition. While the variety of electron diffraction patterns to be expected from icosahedral quasicrystals has been demonstrated for a number of alloys, subtle intensity differences exist among analogous patterns from Al‐Mn, Al‐Cr, Al‐Mn‐Si and Mg‐Al‐Zn‐Cu alloys. Electron diffraction patterns from decagonal quasicrystals can be understood on the basis of an edge‐centred icosahedron as opposed to a vertex‐centred icosahedron for icosahedral quasicrystals. Truncation from two‐dimensional quasicrystals is discussed.
Local translational order in the NiTi2 icosahedral quasicrystal
Authors: Zhang Z. , Kuo K. H.
Published: August 2011

After heating to 400°C, the icosahedral quasicrystal in (Ti1‐IVI)2Ni alloys displays a kind of local or short range translational order as evidenced by a more or less commensurate arrangement of electron diffraction spots along one or several twofold directions. This is supported partly by a high resolution electron microscopic image which shows, in some parts of it, a somewhat regular arrangement of bright points. A structural model with some short‐range translation order in the range of a few nanometres along one of the fifteen twofold directions in the icosahedral matrix has been proposed and its optical diffraction pattern is in good agreement with the experimental observations.
A temperature controlled chamber to allow observation and measurement of uptake of fluorochromes into live cells
Authors: Payne J. N. , Cooper J. D. , MacKeown S. T. , Horobin R. W.
Published: August 2011

A temperature controlled cell chamber is described which permits phase‐contrast and fluorescence microscopy of living cells. It is shown how the cellular uptake of fluorochromes can be investigated both photographically and photometrically. Some sample results are presented for the uptake of Evans Blue.
Low‐temperature scanning tunnelling microscopy and spectroscopy on Pb and Au
Authors: Ramos M. A. , Vieira S. , Buendia A. , Baro A. M.
Published: August 2011

We have designed and built a scanning tunnelling microscope (STM) in order to work at temperatures ranging from 1·2 to 300 K. Tunnelling spectroscopy has been performed in Au and Pb with this STM. Our results on Au show different conductance‐voltage behaviours, their relation with the cleaning state of the tip being discussed. For Pb, the fitting of our I‐V characteristics to a BCS density of states gives A = 1·25 meV for the superconducting energy gap at about 5 K.
Scanning tunnelling microscopy of graphite‐adsorbed molecular species
Authors: Hubacek J. S. , Brockenbrough R. T. , Gammie G. , Skala S. L. , Lyding J. W. , Latten J. L. , Shapley J. R.
Published: August 2011

A new variable‐temperature STM has been used to perform studies of the adsorption and ordering of simple polar molecules such as acetone and dimethylsulphoxide (DMSO) on graphite. The primary objective of this work is to obtain fundamental information which can serve as a basis for studies of complex systems. Following exposure of graphite to acetone vapour, STM images show cloudy patches of acetone drifting across the surface, with individual molecules being indistinguishable. Following prolonged exposure, however, an ordered monolayer forms, having triangular symmetry and 2×2 commensurate periodicity relative to the substrate. Similar results are obtained for DMSO on graphite; however, the monolayer is more closely packed and probably incommensurate with the substrate. In a related effort, nitric acid is shown to be an effective chemical etch for creating steps in basal plane graphite. It is hoped that this, and related techniques, will enable the use of STM to study important chemical systems, such as treated fuel‐cell electrodes, which utilize non‐basal plane graphite.
STM of layered‐structure semiconductors
Authors: Henson Tammy D. , Sarid Dror , Bell L. Stephen
Published: August 2011

We have used scanning tunnelling microscopy to characterize the layered structure semiconductors MoS2, WSe2 and SnS2. Atomically resolved images as well as spectroscopic data in both tunnelling directions have been obtained for the cleaved surfaces of these materials.
Nano‐machining of gold and semiconductor surfaces
Authors: Packard William E. , Liang Young , Dai Ning , Dow John D. , Nicolaides Ruth , Jaklevic Robert C. , Kaiser William J.
Published: August 2011

Using a scanning tunnelling microscope tip formed by cutting a platinum wire, we have modified the surfaces of gold and Hg1‐xCdxTe on a nanometre scale by mechanical contact between the tip and the surface. By using the same tip to form images, we have been able to gain ‘before’ and ‘after’ pictures of surfaces that have been selectively ‘sanded’, controllably ‘chiselled’, and ‘swept’.

We have also obtained images taken under glycerin of Hg1‐xCdxTe and of the diluted magnetic semiconductor Hg1‐xMnxTe.
Metal‐induced reconstructions of the silicon(111) surface
Authors: Park Sang‐il , Nogami J. , Quate C. F.
Published: August 2011

We have used scanning tunnelling microscopy (STM) to study changes in the structure of the Si(111) surface induced by deposition of the group III metals In and Ga. For both metals, several different ordered reconstructions are seen as a function of coverage. The STM images provide new structural information on each of these reconstructions. With In metal deposition, we have seen the surface reconstructions √3×, √3, √31× √31, √7×√3 and 4×1 as the coverage increases. In the case of Ga on Si(111), we have studied structures that exist up to 0·7 ML. At 1/3 ML, there is a √3×√3 structure identical to that of In. Above 0·3 ML there is a different phase that may correspond to the (6·3times6·3) RHEED pattern reported in this coverage range. This surface tends to grow as triangular islands at higher coverages.
Scanning tunnelling microscopy of biomacromolecules
Authors: Guckenberger Reinhard , Wiegräbe Winfried , Baumeister Wolfgang
Published: August 2011

When imaging biomacromolecules with a STM, coating of specimens with a conductive layer is a convenient preparation method which provides a good rate of success. Utilizing evaporated platinum/carbon as a coating film we have investigated two biomacromolecules of very different appearance. The first of these is the HPI‐layer, a natural two‐dimensional protein crystal with a period of 18 nm, which is found on the surface of the bacterium Deinococcus radiodurans. The second specimen is type IV collagen which forms long triple‐helical strands approx. 1·5nm in diameter. The resulting STM pictures compare very well with electron microscopical images.
A technique for studying the development, metamorphosis and morphology of insects, using projection X‐ray microscopy
Authors: Davies Robert Ll. , Worrill Nicola , Bowen Ivor D. , Harrison Timothy J. , Evans Kenneth T.
Published: August 2011

A technique is described for studying insect morphology and flight musculature using an X‐ray microscope. We have shown that a resolution of about 1 μm is possible in intact insects. Electron opaque markers have been used to locate cytochemical sites of enzyme activity, and to investigate gross morphology during developmental metamorphosis in Heliothis armigera.
Acoustic microstructure of mature soya bean (Maple Arrow)
Authors: Kolodziejczyk E. , Saurel J. M. , Fernandez‐Graf M. R. , Attal J. , Fryder V. , Saied A. , Dillmann M. L. , Rey V.
Published: August 2011

The acoustic microscope is used to visualize the acoustic microstructure of wet soya beans. The microacoustic patterns are correlated with their corresponding scanning electron microscopic and light microscopic images. The results show that the acoustic microscope is convenient for rapid and precise studies of thick specimens and gives structural information on a tissular and on a subcellular scale.
A simple technique for in situ embedding of monolayer cultures in Lowicryl K4M
Authors: BOU‐Gharios G. , Adams G. , Moss J. , Shore I. , Olscen I.
Published: August 2011

A number of difficulties are encountered in embedding monolayer cultures at low temperature in Lowicryl K4M resin. In this paper we present a simple procedure using Lab‐Tek Flaskettes in which fixation, processing and embedding of monolayer cultures can readily be achieved.
X‐ray microanalysis with continuous specimen cooling: is it necessary?
Authors: Zglinicki Thomas von , Uhrík Branislav
Published: August 2011

An X‐ray microanalytical preparation technique using continuous specimen cooling and consisting of cryotransfer of frozen sections into the electron microscope, freeze‐drying of the sections within the microscope and analysis at liquid nitrogen temperature is compared with a more conventional technique characterized by freeze‐drying of sections in a vacuum evaporator with subsequent carbon coating, transfer of frozen‐dried sections through the room air into the electron microscope and analysis at ambient temperature. For this comparison elemental concentrations in mitochondria, in areas of the rough endoplasmic reticulum and in the cytoplasm of rat hepatocytes, were measured.

Si is found in abundance in specimens freeze‐dried outside the microscope due to the use of a vacuum evaporator contaminated with pump oil. Radiation damage will be more severe at ambient temperature and is assumed to be the reason for observed differences in S concentration in mitochrondria and the cytoplasm. However, peak‐to‐background ratios for Na, Mg, P, Cl and K are in general the same for both types of preparation.
A perfusion chamber for high‐resolution light microscopy of cultured cells*
Authors: Finch Simon A. E. , Stier Anton
Published: August 2011

A perfusion chamber suitable for general microscopic work on upright and inverted microscopes with cultured cells is described. The device features a minimal internal volume and large field of view within small outer dimensions. In particular the chamber body is very flat to accommodate large‐aperture condenser and objective lenses. It is constructed of innocuous, sterilizable materials, incorporates permanent seals for the windows, is robust and simple to use.
BASIC programs to compute source densities from autoradiographic cross‐fire matrices
Authors: Cau Pierre
Published: August 2011

Two different mathematical procedures to compute source densities from cross‐fire matrices in quantitative EM autoradiography are reported. BASIC programs for a desk‐top microcomputer were written to fit the hypothetical silver grain distribution to the observed real silver grain distribution using a non‐iterative linear process (least‐squares procedure) and an iterative method, which minimizes the chi‐square component between the observed and computed silver grain distributions. The latter procedure uses a Gauss‐Newton algorithm.