bluuebunny/crossref_metadata_2025_split huggingface dataset:
A grinding method for producing sections of large areas of plastic embedded tissues
Authors: Weber Dennis F. , Eisenmann Dale R. , Zaki Abd El‐Moneim 
Published: August 2011

SUMMARYWe have developed a method utilizing relatively thick ground sections of plastic embedded tissue which affords the resolution obtained with 0·5 μm cut sections. The sections, which are permanently affixed to plastic microscope slides, are much larger in area than ultramicrotome sections. Additional advantages are: sections can be destained and restained and selected areas can be examined with various forms of electron microscopy. Autoradiographic studies are also possible. Although the method has a broader application, it is particularly useful in examining the interface between hard and soft tissues.
Microscopic observations on endogenous fluorochromes within a nerve fibre excited by a 325 nm He‐Cd laser
Authors: Cummins J. T. , Rahn C. L. , Rahn R. S. 
Published: August 2011

SUMMARYA microscopic procedure to observe endogenous fluorochromes in superfused tissues is described. In this procedure, a 325 nm beam from a He‐Cd laser is directed through the objective lens of a microscope onto the surface of a brain slice. Fluorescent structures within the tissue can be observed, photographed and measured. A nerve fibre running from the corporis callosi to the dorsal cerebral cortex was studied with this approach. The 325 nm laser beam excited material with an emission peak at 420 nm within a fibre on the cut surface of a rat brain slice superfused with Krebs‐Ringer. A similar fibre was observed in vivo in the exposed mouse brain. Packets of the fluorescent material appear to move within the fibre in vitro. The fluorescence of the fibre was rapidly diminished by cyanide, colchicine, rotenone and the withdrawal of Ca2+. Elevation of [K+] in the superfusate caused a ‘haloing’ of the fibre's granularity without decreasing the total fluorescence. This phenomenon is possibly related to the depolarization by [K+] of neurones. Although the structure of the fluorochrome was not established, it is suggested that it may be a neurotransmitter‐related substance undergoing axonal movement.
The simultaneous use of Hanks' and Hepes buffers in the preparation of human leucocytes for SEM observation
Authors: Lalague E. D. , Haviernick S. , Corvellec M.‐R. , Pelletier L. , Derghazarian C. , Cousineau G. H. 
Published: August 2011

SUMMARYLeucocytes were isolated from the peripheral blood of normal individuals and prepared for SEM observation. The addition of the buffer Hanks and Hepes to the glutaraldehyde fixative was found to maintain the initial ambient pH throughout cell manipulation, and to allow satisfactory preservation of surface architecture.
A simple quantitative analysis of phase contrast microscopy, not restricted to objects of very low retardation
Authors: Goldstein D. J. 
Published: August 2011

SUMMARYA simple vector analysis of the diffraction of light by an ideal, extended phase grating suggests that irrespective of the amount of retardation imposed on the light passing through a transparent microscopic object the diffracted light leaving the object plane is precisely 90° out of phase with the resultant direct (zero‐order diffracted) light. In positive phase contrast microscopy, with a 90° phase plate of transmittance T for the direct light, the image and halo respectively have intensities relative to the original illumination of (√T.cos 1/2Φ–sin 1/2Φ)2 and (√T.cos 1/2Φ+sin 1/2Φ)2. The empty background has an apparent intensity of T. Zero intensity of the image is seen if T=tan2(1/2Φ), and reversal of contrast if T≤tan2(1/4Φ). The same equations can be used to predict the intensities of the image and halo in negative phase contrast microscopy, if Φ is replaced by (360°‐Φ).Unlike the ‘standard’ description of phase contrast microscopy, exemplified by Barer's vector method, the present account is consistent with the conservation of energy and is not restricted to very small object retardations. Barer's method is, however, theoretically valid for objects of any shape, and the two approaches may perhaps be regarded as complementary.
Improved low dose technique for high resolution electron microscopy
Authors: Chalcroft J. P. , Tavener A. 
Published: August 2011

SUMMARYThe use of low‐dose electron micrography can result in unacceptable focusing errors if the specimen plane between focus and micrography areas is tilted. The corrective method applied here involves the use of two focus areas symmetrically disposed with respect to the area to be recorded. A reasonable estimate of correct focus can be made by interpolation between the two known settings.Annular illumination applied to the specimen immediately prior to recording is recommended to reduce any likelihood of specimen drift caused by changing thermal gradients.The methods involve only minor modifications to existing circuitry, are easy to implement, and have resulted in a dramatically improved percentage of well‐focused micrographs.
Permanent slides of freshly collected algae: a review of techniques
Authors: Foote MaryAnn 
Published: August 2011

SUMMARYA number of techniques are given for preparing permanent slides of freshly collected algae. The methods reviewed are suitable for phytoplankton, delicate species, filamentous algae and marine samples. Included are traditional techniques using corn syrup or glycerin and also a new technique with a commercial histological product.
Incident light microscopy of normal and transformed cultured fibroblasts stained with Coomassie blue R250
Authors: Paddock Stephen W. 
Published: August 2011

SUMMARYIncident light microscopy of fibroblasts stained with Coomassie blue R250 results in images of the cytoskeleton with a similar high contrast to those obtained by specific immunofluorescence microscopy. This technique is especially useful for the routine visualization of the cytoskeleton of transformed cells.
The application of automatic image analysis in studies of bubble populations produced by radiation damage
Authors: Shaw M. P. , Kohler V. L. , Ralph Brian 
Published: August 2011

SUMMARYThis paper describes a method by which automatic image analysis can be applied to the study of size distributions of small (< 5 nm) radiation induced bubbles. Statistically valid results are obtained directly from transmission electron microscope negatives and the optimum imaging conditions for obtaining reliable data are discussed.
The preservation of mucus and surface‐associated microorganisms using acrolein vapour fixation
Authors: Garland C. D. , Nash G. V. , McMeekin T. A. 
Published: August 2011

SUMMARYThree fixation schedules were devised and compared in terms of their influence on the preservation of mucus and surface‐associated microorganisms contained within it. Different mucus‐secreting epithelial tissues from normal and spoiled oysters and normal rats were examined by scanning and transmission electron microscopy and light microscopy. On all tissues, mucus was best preserved in specimens fixed by 10% acrolein vapour for 1 h then immersed in 3% glutaraldehyde—3% formaldehyde fixative containing 0·05% ruthenium red, cacodylate buffer pH 7·4, for at least 3 h. This fixation schedule also greatly increased the preservation of microorganisms in mucus in specimens from spoiled oysters and normal rats. In contrast, the retention of mucus and surface‐associated microorganisms was poor in tissues fixed either by 1% OsO4 vapour for 1 h followed by immersion in combined aldehyde fixative, or by direct immersion.The quality of preservation of the mucus layer, epithelium and sub‐epithelium was also noted by transmission electron microscopy in tissues prepared by the different fixation schedules. Cellular preservation was satisfactory in directly immersed tissues but poor in vapour fixed specimens.
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

SUMMARYPhysiological 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

SUMMARYA 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

SUMMARYFlow 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

SUMMARYIn 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

SUMMARYA 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

SUMMARYFailure 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

SUMMARYIn 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

SUMMARYPetroleum 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

SUMMARYEpoxy‐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

SUMMARYWe 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

SUMMARYThe 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

SUMMARYModern 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

SUMMARYDimensional 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

SUMMARYSupercooled 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

SUMMARYA 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.
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

SUMMARYThree 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

SUMMARYVery 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

SUMMARYA 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.