bluuebunny/crossref_metadata_2025 huggingface dataset:
Digitally Controlled Multipoint STEM-EDX Microanalysis
Authors: Boyes E. D.
Published: June 2020

Spatially resolved microchemical analysis of thin specimens by STEM-EDX can with advantage be performed using a series of quantitative analyses at a number of selected discrete points in a digitally controlled array.

The conventional line traces in X-ray peak intensity are not necessarily a good indication of elemental distributions. Substantial errors can occur as a result of the need for spectrum processing, X-ray corrections and in the case of thin specimens due to variations in specimen thickness which may be associated with differential polishing of regions of different chemical composition during sample preparation. In some circumstances ratio line scanning1 may be an improvement.
The Cytological Basis for Cortisone Action on Rat Liver Cells
Authors: Friedberg Jonathan E. , Cardell Robert R.
Published: June 2020

The objective of this investigation is to provide morphological information on the action of a hormone. We have chosen to study the action of cortisone on the rat liver because it is established that this steroid has a stimulatory effect on the synthesis of the gluconeogenic enzymes. The glucocorticoids (including cortisone) are secreted by the adrenal cortex; hence, adrenalectomy renders the animal deficient in these hormones and impairs carbohydrate metabolism in the hepatocyte by reducing gluconeogenesis. Cortisone injection into an adrenalectomized rat increases the capacity of this cell to produce glucose from non-carbohydrate precursors. We have studied with the electron microscope liver cells from normal, adrenalectomized, and adrenalectomized, cortisone-treated rats. All rats were allowed free access to saline solution and were fasted for 15 hours before sacrifice.

The liver cell of the adrenalectomized rat (Fig. 1) presents several striking alterations as compared with the normal hepatocyte. A conspicuous difference is the almost complete absence of particulate glycogen after the animal has been fasted for 15 hours. More remarkable is the very sparse development of the smooth endoplasmic reticulum (SER) in these glycogen-depleted cells.
Light and Electron Microscopic Observations of the Urinary Bladder Epithelium in the Rhesus Monkey
Authors: Moize Sarah M. , Richter Ward R.
Published: June 2020

Our continued interest in urinary bladder epithelium led to a preliminary observation of these cells in the monkey revealing an epithelium many cells in thickness and ultrastructure suggestive of a high rate of metabolic activity at all cell levels. This finding differs from reports on other species where an epithelium of 3 cell layers has been described in mice, rats, rabbits and dogs. To expand this comparative study samples were collected from 10 monkeys. When cut at right angles to the bladder wall the epithelium is 6-12 cells thick with a wide range in cell size and shape (Fig. 1). The epithelium can be arbitrarily divided into 3 zones based on the staining intensity of the cells as observed by light microscopy. The surface layer of oval, pale staining giant cells may display a large round nucleus with dense staining cytoplasmic granules. The intermediate zone 4-8 cells thick shows an increased stain reaction in the cytoplasm and nucleus. A dark staining nucleus is frequently present as well as clusters of cytoplasmic granules of varying stain intensities. In the basal zone the cells are smaller with the nucleus and cytoplasm staining intensely. Prominent intercellular spaces appear to vary in width with the degree of collapse in the bladder wall. Directly beneath the basal cells is a delicate basal lamina, a network of blood capillaries and associated fibroblasts supported on a connective tissue lamina.
Correlated Changes Between the Golgi Apparatus and Cell Wall Formation During Sporogenesis
Authors: Ridgway John E.
Published: June 2020

During the formation of cell wall layers of the sporocyte and spore during sporogenesis in Anthoceros fuciformis Mont., there appears to he an intimate relationship between the Golgi apparatus and cell wall deposition. As the initial sporocyte wall if formed, the cisternae of the Golgi apparatus become extensively hypertrophied and produce large vesicles which move through the cytoplasm and empty their contents through the plasma membrane to form the developing primary sporocyte wall layer (I) (Figure 1). In both methods of fixation used, a similiar electron density was observed in the contents of the Golgi cisternae, the Golgi secretory vesicles, and the components of the sporocyte wall layer-I.
Fine Structure of Meiotic Prophase Chromosomes in Lilium Longiflorum
Authors: Moens Peter B.
Published: June 2020

The presence of the tripartite ribbon within synapsed homologues has been reported for a large number of sexually reproducing organisms (over one hundred species, including fungi, plants, vertebrates and invertebrates). The absence of the ribbon in some species is associated with uncommon synaptic behaviour of meiotic prophase chromosomes (Drosophila melanogaster males, Drosophila melanogaster females homozygous for synapsis suppressing mutant C3G, and achiasmatic Dipteran species, reported by G. F. Meyer, 1964, Third European Regional Conference on Electron Microscopy). The tripartite ribbon, or synaptinemal complex, may therefore be assumed to be related to pairing of homologues at meiosis. The presence of the complexes and multi-complexes in non-meiotic cells such as insect obcyte nurse cells and spermatids suggests a somewhat broader function of the complexes. This is further supported by the occurrence of complexes in non-homologous paired chromosomes in the pollen mother cells of haploid tomato plants.
Sites of Adsorption of the Bacteriophages T3 and T5 on the Wall of Escherichia Coli B.
Authors: Bayer Manfred E.
Published: June 2020

Bacterial viruses adsorb specifically to receptors on the host cell surface. Although the chemical composition of some of the cell wall receptors for bacteriophages of the T-series has been described and the number of receptor sites has been estimated to be 150 to 300 per E. coli cell, the localization of the sites on the bacterial wall has been unknown.

When logarithmically growing cells of E. coli are transferred into a medium containing 20% sucrose, the cells plasmolize: the protoplast shrinks and becomes separated from the somewhat rigid cell wall. When these cells are fixed in 8% Formaldehyde, post-fixed in OsO4/uranyl acetate, embedded in Vestopal W, then cut in an ultramicrotome and observed with the electron microscope, the separation of protoplast and wall becomes clearly visible, (Fig. 1, 2). At a number of locations however, the protoplasmic membrane adheres to the wall even under the considerable pull of the shrinking protoplast. Thus numerous connecting bridges are maintained between protoplast and cell wall. Estimations of the total number of such wall/membrane associations yield a number of about 300 per cell.
Freeze Etching With Radiant Energy in a Simple Cold Block Device
Authors: McAlear James H. , Kreutziger G. Oscar
Published: June 2020

Freeze etching of biological samples was developed by Steere, refined by Moor et al, and simplified by Bullivant. Moor's device permitted the rapid freezing of specimens, precision fracturing in vacuo and etching of the fractured surface by raising the specimen temperature. Bullivant’s simplification featured cleaving the frozen specimen outside of the vacum under liquid N and then protecting the cleaved surface in a cold block with a tight fitting lid until he was ready to shadow and replicate. He could not etch with this device and much detail in the specimen was lost.

The present device uses the cold block and lid concept. The lid has tunnels through which shadowing and replication of the specimen surface occurs. This lid, however, is free to swing bringing a knife on its lower surface through the specimen which is affixed to a pedestal on the upper surface of the base (Figures 1, 2 & 5). After cleaving the specimen the lid passes to its clockwise stop bringing the tunnels in the lid in line with the electrodes and the specimen surface.
The Correlation of Cellular Ultrastructure and Electrophysiology
Authors: DeFelice L.J. , Challice C.E.
Published: June 2020

Attempts have been made to identify cells of special electrophysiological significance for electron microscopy, particularly from the heart. When the area of interest is very small, the correlation has been less certain. A technique has been developed which allows identification to within about ten cells in any direction, simultaneously defining one axis of orientation. The aim was to identify regions of special electrophysiological interest in the atrioventricular node of the rabbit heart, and involved fixing the tissue with the tip of the microelectrode in the recording position immediately following measurement of the action potential.
Action of Estrogen on the Fine Structure of the Rabbit Uterus: Changes in Distribution of Capillary Mucopolysaccharides and Endometrial ATPase Activity
Authors: Henzl Milan , Smith R. E.
Published: June 2020

In a continuing study on the subcellular cytochemistry of the rabbit uterus in response to exogenous estrogen, our attention focused on sequential changes in endometrial capillaries. Tissue segments from castrate (30 days post-operative), and ovariectomized animals administered daily estradiol benzoate (1 mcg/Kg b. wt.) for 1, 5, and 10 days starting on 30th day after castration were fixed 5 hours in cold 1.5% singly distilled glutaraldehyde containing 1% sucrose, buffered at pH 7.4 with phosphate, and an osmolarity of 290 to 298 milliosmols. Nonfrozen sections were cut at 30-40μ using a Sorvall TC-2 Tissue Sectioner, and stored in cold sucrose acetate-veronal buffer for short periods prior to cytochemical reactions. ATPase activity was demonstrated at neutral pH by the lead-salt procedure of Wachstein and Meisel. Mucopolysaccharides (MPS) at pH 2.6 were demonstrated by a slightly revised Periodic acid—Thiocarbohydrazide—Osmium tetroxide method of Seligman and coworkers (J. Hist. Cytochem. 13:629, 1965). Sections reacted for ATPase were subsequently postfixed in buffered 1% 0S04, dehydrated, and embedded. Sections reacted for MPS were dehydrated and embedded in Araldite 502 without propylene oxide.
Quantitative Estimation of the Loss of Membrane Images Resulting From Oblique Sectioning of Biological Membranes
Authors: Loud Alden V.
Published: June 2020

Williams and Kallman pointed out one of the major artifacts in the electron microscopy of biological thin sections, namely, the failure to form images of membranes which are inclined at large angles within the section. This loss is a significant consideration in the qualitative interpretation of electron micrographs and especially in the quantitative assay of endoplasmic reticulum and mitochondrial cristae membranes. In order to estimate the effective loss of membrane images it would be desirable to use a specimen which provides a considerable length of membrane tilted at a known angle and a simple method of measuring its “visibility”. The spherical nuclear envelopes of rat liver parenchymal cells satisfy these conditions. Figure 1 shows part of a binucleate liver cell in which the nuclear membrane is clearly visible around the larger section but blurred by oblique orientation in the smaller section.
Pathological Protein Biosynthesis in the Vestibular Nucleus and Other Neurons of Rat Brain During Kanamycine Administration
Authors: Bak I. J.
Published: June 2020

An electron microscopic study was made on cells of the vestibular nucleus and other neurons of rat brain during kanamycine and streptomycine treatment.

15 healthy male rats with an average body weight of 250-300 g were used throughout the whole experiments. The animals were devided into 3 groups and were given intramuscular injections of 200mg/kg of streptomycine and 400mg/kg of kanamycine respectively) the 3rd group was used as control. After repeated injections over a period of 5 days, the brains were removed and the vestibular nucleus, substantia nigra and pineal gland were harvested and fixed in 6% glutaraldehyde, buffered with phosphate at pH 7.4 prior to OsO4 fixation.

The tissues were dehydrated in a series of graded alcohol and embedded in Epon 812, sectioned with LKB ultratome, stained in both uranyl acetate and lead citrate and studied in a Siemens Elmiskop 1A.
The Chromatoid Body in Syrian Hamster Spermatocytes: Its Morphology and Distinctive Characteristics
Authors: Krishan A. , Uzman B. G.
Published: June 2020

The chromatoid body (“sphere chromatophile”) has recently been characterized in the developmental stages of animal sperm cells as a cytoplasmic structure rich in RNA and basic proteins but containing no DNA. In electron micrographs of widely divergent species several different structures have been designated chromatoid bodies: aggregates of dense granules; bodies with concentric membranous substructure; and tubules (500 A in diameter) arranged in parallel array.

We shall describe, in early spermatocytes of the Syrian hamster, masses of fine, amorphous, electron-dense material adjacent to the nuclear membrane often in close proximity to nuclear pores (Figure 1); similar material has been so identified in other mammalian species. In later spermatocytes and in spermatids, this same material is recognized closely associated with the centriolar area which in these stages lies at the posterior end of the nucleus or sperm head.
75 KEV Electrostatic Energy Analyzer and Filter Lens
Authors: Edmonds J.D. , Silcox J.
Published: June 2020

A unipotential electrostatic energy analyzer and filter lens has been developed for the Hitachi HU-11A electron microscope which can simultaneously analyze the selected area energy loss spectra of the transmitted and diffracted beams with a resolution of about 0.5 eV (see Fig. 1). The electron image or diffraction pattern can also be filtered of those inelastically scattered electrons which lose more than a few eV, but further work is needed to reduce the aberrations in the image. The analyzer consists of a high voltage electrode inserted between grounded electrodes in the diffraction chamber of the Hitachi HU-11A (see Fig. 2). Earlier work by Shaffer, Silcox and Siegel at 50 keV demonstrated that such an analyzer placed between the intermediate and projector lenses of an experimental microscope was capable of about 1 eV resolution. The electrode geometry is patterned after the filter lens work of Hahn. The effects on the image of changing the lens parameters, altering the alignment of the central electrode and varying the electron beam over a few hundred volts, have been investigated experimentally.
An Electron Transmission Microscopy Study of Chemically Reduced Cobalt
Authors: Fisher R. D. , Jackson F. J. , Morton V.
Published: June 2020

The early growth stages of chemically reduced cobalt on thin Formvar substrates were examined by electron transmission microscopy. The growth characteristics were examined as a function of the average effective thickness and the deposition rate (1 Å/sec. to 6 Å/sec.). The chemical reduction method is essentially a controlled autocatalytic reduction of cobalt ions from solution by hypophosphite ions in the presence of a catalyst (Co, Ni, Pd, Al). Thin Formvar films prepared on a glass base were indirectly catalyzed with palladium by immersion in a stannous chloride solution, rinsing and immersing in a palladium chloride solution.
Studies on Extended Dislocation Nodes in a ζ-Phase Silver-Tin Alloy
Authors: Ives L. K. , Ruff A. W.
Published: June 2020

A determination of the intrinsic stacking fault energy as a function of composition has been previously reported for the face-centered-cubic phase in the silver-tin alloy system. The method involved direct measurements on extended dislocation nodes observed by transmission electron microscopy in alloys containing from 0 to 7.8 at.% tin. The stacking fault energy γ was found to decrease from a value of 22.8 erg/cm3 for silver to 4.2 erg/cm2 for the 7.8 at.%. alloy. Figure 1 shows the phase diagram for this system. At room temperature, the α-phase limit occurs at about 8.5 to 9 at.%. tin. A two-phase region extends to approximately 11.5 at.% followed by the ζ- Ag Sn phase region which exists to about 17 at.% tin. A series of hexagonal ζ alloys of various compositions are presently under study to determine the variation of the stacking fault energy with composition. Preliminary results indicate that the stacking fault energy increases with increasing solute concentration in the ζ-phase region. Extended dislocation nodes have been observed in all the ζ alloys, together with extended ribbons in the dilute alloys. This paper will consider only the results obtained on the most dilute alloy (12 at.% tin) and compare them with the a-phase results.
Coprecipitation of Barium and Lead Sulfates
Authors: Takiyama Kazuyoshi
Published: June 2020

Coprecipitation studies have been generally done from a stand point of analytical chemistry, but it is important to study on the coprecipitation from a view point of crystallography to clarify the mechanism of impurification of precipitates.

Barium and lead sulfates belong to the orthorhombic system, Vh16, and the spacings of the crystals are slightly different from each other.
Electron Diffraction Characteristics of Two-Phase Structures in Alnico 6
Authors: Dash J. , Bitler W. R.
Published: June 2020

Alnico permanent-magnet alloys can be prepared in a metastable single-phase condition by solution-treatment above 1200°C and rapid quenching to room temperature. The metastable phase, thought to have ordered BCC structure, can be decomposed by further heating at temperatures below 850°C according to the reaction, α − α1 + α2 The phase α1, is thought to be weakly magnetic and composed mainly of Ni and Al, whereas α2 is thought to be strongly magnetic and composed mainly of Fe and Co. Both α1 and α2 are thought to have BCC structure of nearly the same lattice parameter, and one or both of the phases may be ordered. The uncertainty in available information on the properties of these phases arises because the phase transformation occurs on such a fine scale (∼100 Å particle diameter) that it is very difficult to obtain unambiguous information on the phases separately.
Gold Microcrystals of Pentagonal Symmetry
Authors: Bottoms W. R. , Morriss R. H.
Published: June 2020

Face-centered cubic metallic crystals exhibiting fivefold symmetry have been observed by a number of investigators. Schwoebel has recently observed this anomalous structure in carbon replicas of gold which was vapor deposited onto electropolished gold single crystals. His results are consistent with a model proposed by Melmed and Hayward according to which the pentagonal crystal consists of five segments, each separated by a twin boundary. In an effort to explain this unusual morphology, Schwoebel has suggested the possibility of impurity atoms with a diameter approximately 0.7 that of gold serving as nuclei around which five gold atoms cluster in a modified close-packed arrangement.

In this study microcrystals of gold exhibiting a similar structure have been observed in colloidal suspensions prepared by the chemical reduction of chlorauric acid with oxalic acid. The hydrosols contain gold particles of three general morphologies: thin platelets of trigonal symmetry, cube-octahedra with the {111} faces primarily developed and the {100} faces developed to a lesser extent, and particles exhibiting fivefold symmetry.
A Replica Technique for the Inside Surfaces of Small Diameter Pipes and Tubes
Authors: Gregory T. G.
Published: June 2020

A nondestructive replica technique permitting complete inspection of bore surfaces having an inside diameter from 0.050 inch to 0.500 inch is described. Replicas are thermally formed on the outside surface of plastic tubing inflated in the bore of the sample being studied. This technique provides a new medium for inspection of bores that are too small or otherwise beyond the operating limits of conventional inspection methods.

Bore replicas may be prepared by sliding a length of plastic tubing completely through the bore to be studied as shown in Figure 1. Polyvinyl chloride tubing suitable for this replica process is commercially available in sizes from 0.037- to 0.500-inch diameter. A tube size slightly smaller than the bore to be replicated should be used to facilitate insertion of the plastic replica blank into the bore.
The Preparation of Fine Recrystallized Tungsten Wire for Transmission Electron Microscopy
Authors: Koch E. F. , Walter J. L.
Published: June 2020

In a study of the structure and properties of tungsten wire used for lamp filaments, it became desirable to perform transmission electron microscopy on the wire in the annealed as well as in the drawn condition.

Wire used for lamp filaments is generally drawn to diameters less than 0.010" which is too fine for the preparation of transmission samples from single wires. Thus, it is clear that some assembly of wires must be used to form a “wire sheet” similar to that used by Glenn and Duff.

Commercially-doped (218) tungsten filament wire in diameters of 0.001", 0.004", and 0.010" was wound on 1" square tungsten plates, 0.060" thick, using standard coil-winding techniques. After winding, the plates were annealed at temperatures of 1800°C to 2200°C, in vacuo. Following the anneal, the samples were treated in one of two ways. The 0.010" and 0.004" diameter wire sheets were encapsulated in epoxy and ground from both faces to a thickness of about 1/2 the wire diameter. The exposed wires were then electropolished with 107. NaOH electrolyte. The epoxy protected the edges of the flat wires so that the central area of the wire could be thinned.
Whither Scanning Electron Microscopy
Authors: Everhart T. E.
Published: June 2020

Although scanning electron microscopes have been available commercially for a relatively short time, their use is increasing rapidly. Countless persons have marvelled at their great depth of field, which produces an easily interpreted image of a three-dimensional object. Trained electron-microscopists have been impressed by the minimal sample preparation required for scanning microscope observation of inorganic objects, and of some organic objects. Non-specialists find the instrument easy to use, because many of the controls are related to familiar controls on television sets, on cathode-ray oscilloscopes, etc., and because the image on the cathode-ray tube screen is easy to interpret. Now seems the opportune moment to re-emphasize how the scanning electron microscope (SEM) differs fundamentally from the transmission electron (TEM), in order to insure that constraints imposed by the physics of image formation in the TEM will not be taken subconsciously as constraints in the SEM too.
The Broad Applications of the Scanning Electron Microscope
Authors: Nightingale C. T. , Summers S. E. , Turnbull T. P.
Published: June 2020

The ease of operation of the scanning electron microscope has insured its wide application in medicine and industry. The micrographs are pictorial representations of surface topography obtained directly from the specimen. The need to replicate is eliminated. The great depth of field and the high resolving power provide far more information than light microscopy.
Examination of Schistosome Cercariae and Schistosomules by Scanning Electron Microscopy
Authors: Johnson D. , Moriearty P.
Published: June 2020

Since several species of Schistosoma, or blood fluke, parasitize man, these trematodes have been subjected to extensive study. Light microscopy and conventional electron microscopy have yielded much information about the morphology of the various stages; however, scanning electron microscopy has been little utilized for this purpose. As the figures demonstrate, scanning microscopy is particularly helpful in studying at high resolution characteristics of surface structure, which are important in determining host-parasite relationships.
Scanning Electron Microscopy of Human Bone Marrow
Authors: Trubowitz S. , Broers A. , Pease R. F. W.
Published: June 2020

Limitation of both depth of field and resolution of the light microscope directed attention to the scanning electron microscope in the examination of the structural and organizational details of the human marrow. Particles of marrow tissure, obtained by aspiration from the sternum, were rapidly separated from the aspirate,, fixed in 6.75% ice-cold glutaraldehyde for ten minutes and post fixed in 1% buffered osmic acid for 30 minutes. The particles were placed on aluminum specimen stubs, coated with a few hundred angstroms of aluminum and then inserted in the microscope for examination.
Use of Glow discharge for Inhibiting Agglomeration of Gold Films on Glass
Authors: Paulson G. , Friedberg A.
Published: June 2020

A major problem which limits the use of vapor deposited gold films on glass surfaces is the extreme agglomeration or aggregation of the gold during the initials tages of nucleation. An agglomerated film consists of discrete islands or aggregates of gold, and is electrically discontinuous. As the islands grow larger and “touch”, the films become good electrical conductors. Agglomerated gold films may be as thick as 300 angstroms or even thicker before they become electrically continuous. For certain applications it is desirable to prepare electrically continuous films with high optical transparency. Agglomerated films which have adequate conductivity commonly transmitless than 50% of visiblelight. In a recent study, we have investigated the various parameters which control the agglomeration tendencies of vapor deposited gold films on glass substrates. The effect of an oxygen glow discharge in reducing agglomeration is presented here.
Technique for Stripping Evaporated and Sputtered Films
Authors: Bienes H. , Larson H. W. , Eubank W. R.
Published: June 2020

The field of D.C. and R.F. Sputtering has grown rapidly in recent years and the question arose how the morphology of sputtered thin films compared with that of evaporated thin films. One of the stumbling blocks in shedding more light on this subject was the difficulty in stripping sputtered films from suitable amorphous substrates (similar to glass) with minimum introduction of strains. This search covered materials from which thin sputtered or evaporated films could easily and rapidly be detached.
Electron Diffraction by an Optical Grating
Authors: Curtis G. H. , Ferrier R. P.
Published: June 2020

Carbon replicas of optical diffraction gratings can be used, not only for magnification calibration in electron microscopy, but also as angular standards in small-angle electron diffraction. These replicas are usually shadowed with a heavy material to improve image contrast, but we acquired some unshadowed samples (kindly supplied by Mr. R.H. Alderson of AEI Ltd,) for the experiments described below. The gratings are cross-ruled with 2,160 lines per mm to give a spacing of 463 nm and a diffraction angle of about 9 microradians at U=80KV.
A New High Resolution Transmission Electron Microscope with Second-Zone Objective Lens
Authors: Tochigi H. , Uchida H. , Shirai S. , Akashi K. , Evins D. J. , Bonnici J.
Published: June 2020

A New High Excitation Objective Lens (Second-Zone Objective Lens) was discussed at Twenty-Sixth Annual EMSA Meeting. A new commercially available Transmission Electron Microscope incorporating this new lens has been completed.

Major advantages of the new instrument allow an extremely small beam to be produced on the specimen plane which minimizes specimen beam damages, reduces contamination and drift.
Development Program for a 500-kV High Resolution Microscope
Authors: Worsham R. E. , Mann J. E. , Richardson E. G. , Slaughter G. G. , Ziegler N. F.
Published: June 2020

The goal of the development program for high resolution microscopy at Oak Ridge National Laboratory is a 100-500 kV instrument with a point-to-point resolution of at least 1Å. As reported previously, this microscope is intended for biological specimens to be observed at liquid helium temperature. This resolution is to be achieved principally by reduction of the primary spherical aberration for the objective lens with a quadrupole-octupole system of lenses.
Early Effects of Salicylate on Gastric Mucosal Ultrastructure
Authors: Pfeiffer C. J. , Weibel J. , Roth J. L. A.
Published: June 2020

For many years the adverse effects of salicylate on the gastric mucosa have been recognized. However, the mechanism of salicylate-induced gastric bleeding remains obscure. In order to determine the cellular morphologic sites of action of salicylate, aspirin-treated animals were studied during the early pathogenesis of the gastric mucosal, bleeding diathesis.
A Bacterium Capable of using Phytol as its Sole Carbon Source, Isolated from Algal Sediment of Mud Lake, Florida
Authors: Hoag K.B. , Tousimis A.J. , Bradley W.H.
Published: June 2020

As part of an investigation related to the biological and chemical nature of Mud Lake in north central Florida, the lake water and sediment were examined to determine whether any micro-organisms existed which were capable of metabolizing pure phytol. Phytol is a side chain of the chlorophyll molecule and is considered the most likely precursor of the isoprenoid hydrocarbons found in the oil shale of the Green River Formation of Colorado, Wyoming, and Utah. Phytol and its metabolic products are also known to play an important role in Refsum's disease. From the algal sediment of this lake, which is believed to be a modern analogue of the oil shale, we have isolated a bacterium that will attack phytol and can survive in cultures where phytol is the sole source of carbon.
Effects of Denervation on Insect Muscle
Authors: Randall Winnifred
Published: June 2020

Some insect muscles disappear prematurely or remain for relatively long periods after denervation, depending on the hormonal environment. These effects do not occur in all insects. Do the ultrastructural changes in denervated insect muscle resemble normal metamorphic degeneration? To determine this, I cut the nerves which supply the proleg retractor muscles of the wax moth, Galleria mellonella (L.), and followed changes in their structure. There are three retractor muscles in a proleg, and each muscle is a single fiber. Two of these muscles in each proleg of the third abdominal segment normally degenerate during the first 24 hours of the pupal stage, and the third fiber remains a week longer.
Adsorption of DNA on Aluminum-Mica
Authors: Gordon C.N. , Kleinschmidt A. K.
Published: June 2020

The use of cleft mica as a substrate for mounting DNA and other biological macromolecules for electron microscopy was first proposed by Hall. Macromolecules were sprayed onto the mica, pre-shadowed with Pt or Pt-Pd and then replicated with C or SiO (“pseudo-replication”). A major disadvantage of the technique as described by Hall resides in spraying the solutions since this can degrade some biomacromolecules. In particular, it has been shown that DNA is degraded by the shearing forces attendant in spraying DNA solutions.
The Ultrastructure of Muscular Cirrhosis of the Human Lung
Authors: Brinkman G. L. , Brooks N. L.
Published: June 2020

Muscular cirrhosis of the lung is an uncommon form of idiopathic fibrosis in which excessive amounts of collagen and non-striated muscle form in the alveolar septa interfering with the transport of oxygen and carbon dioxide across the alveolar membrane.

The patient in this case was a man aged 56 years, who had had progressive shortness of breath for three years. Thoracotomy was performed and the lingular lobe biopsied. The tissue was fixed in 3% phosphate buffered gluteraldehyde, and after dehydration in acetone, embedded in Vestopal. Thin sections were stained with uranyl magnesium acetate.
Temperature Dependance of Freeze-Etch Images
Authors: Staehelin L. Andrew , Bertaud William S.
Published: June 2020

Freeze-etching has been termed the “true to nature” preparation method for electron microscopy because certain ceils remain viable throughout the treatment. However, even in the frozen state aqueous systems undergo various phase changes with temperature and little is known about the effects of these changes on frozen biological materials.

Our present investigation was designed to provide some information as to what extent the temperature(s) at which the specimens are held during the various freeze-etch procedures can influence the final image of the material.
The Pathogenesis of Experimental Mycotic Encephalitis
Authors: Swenberg James A. , Koestner Adalbert , Tewari R.P.
Published: June 2020

Previous investigations of pathogenetic mechanisms in mycotic encephalitis have been restricted to light microscopic and mycologic approaches. In this study, electron microscopy was utilized to determine the mode of vascular penetration and the cellular and subcellular host-parasite interrelationships in brains of mice infected with Oidiodendron kalrai. This newly isolated fungus was selected because of its ability to consistently produce encephalitis with gross and microscopic lesions similar to those observed in naturally occuring mycoses.
A Light and Electron Microscopic Study on the Development of Canine Distemper Inclusion Bodies in vitro
Authors: Howard Joanne , Chapman A. L.
Published: June 2020

It has been demonstrated by a number of investigators that certain strains of canine distemper virus (CDV), when grown in an appropriate monolayer of culture cells, manifest characteristic cytopathic effects (CPE). These cells are distinguishable by the appearance of eosinophilic cytoplasmic inclusions, nuclear inclusions, syncytial formation and/or spindal-shaped cells. Although virus particles have been described using a negative stain, the structure of the sectioned virus and inclusion body has not been reported. Therefore a light and electron microscopic study of the distemper inclusion body was undertaken to determine its developmental morphology. The Ondersproot strain of canine distemper virus was inoculated into monolayers of Hep2 cells. The cells were harvested at various times between 1 and 168 hours post-infection, centrifuged at 2,500 RPM for 15 minutes, fixed for one hour in glutaraldehyde and stored overnight in.2M buffered sucrose.
Nuclear Structure in Rainbow Trout Spermatozoa as Revealed by Freeze-Etching
Authors: Koehler James K.
Published: June 2020

Freshly obtained milt from spawning rainbow trout were treated with 10% glycerol in fish ringer for several hours at 4°C. Centrifuged pellets of cells were frozen quickly in liquid freon 22 and examined by the freeze-etching method. Slowly frozen cells, or those treated with DMSO, gave generally poorer results than the method described above.

Several sperm heads are seen in Figure 1. Note that the sperm tails are fractured away at the point of insertion into the head (arrows). The plane of fracture most commonly proceeded around the sperm head membrane, however, on occasion a cross fracture through the injclear region could be seen (Figure 2).
Principles and Techniques of Stereo Electron Microscopy
Authors: Cole Arthur
Published: June 2020

Fig. 1 illustrates the basic principles of conventional stereo electron microscopy. An image is recorded for each of two tilt positions of the specimen. Consider the points A and B where B lies at the distance z below A. The displacements Pl and Pr produced by the tilt - ⊝ and + ⊝, are imaged as relative parallax displacements and on the film. When the stereo pair is viewed by binocular vision the positions of the points are reconstructed at A'” and B'”. For the conventional geometry used in electron microscopy (i.e., object size and objective aperture very small compared with the focal length) it can be shown that where M is the microscope magnification. Thus, a measurement of the parallax value determines z when M and ⊝ are known.

Fig. 2 illustrates an instrument for viewing and analysing stereo pairs. Both plates are translated together by the master stage. Proper stereo alignment is achieved by use of sub-stages which allow rotation of either plate and translation of the right plate.
A New Electron Dense Stain For Elastin
Authors: Albert Ernest N.
Published: June 2020

Only phosphotungstic acid (PTA) has been demonstrated to have a reasonably specific affinity for elastin in electron microscopy. However phosphotungstic acid is effective as a specific stain for elastin only at very acid pH. If the pH is increased, PTA is no more a specific stain for elastin, instead it acts as a general protein stain. Therefore at low pH only elastin is visible and one is unable to study the morphological relationships of the elastic components to their surrounding structures due to the virtual absence of contrast in them.

Tetraphenylporphine sulfonate (TPPS) has, been shown to have a specific, affinity for elastic tissues of the body in fluorescence microscopy. However TPPS does not impart electron density to this tissue and thus is not suitable for electron microscopic studies. Therefore tetraphenylporphine sulfonate was complexed with various heavy metals in order to use it as a specific stain for elastin in electron microscopy.
Uranyl Acetate and Rotary Shadowing to Increase the Contrast of Small Aggregated Virus Particles
Authors: Ellis Lee F. , Van Frank Richard M. , Kleinschmidt Walter J.
Published: June 2020

The extract from Penicillum stoliniferum, known as statolon, has been purified by density gradient centrifugation. These centrifuge fractions contained virus particles that are an interferon inducer in mice or in tissue culture. Highly purified preparations of these particles are difficult to enumerate by electron microscopy because of aggregation. Therefore a study of staining methods was undertaken.
An Ultra High Vacuum Modular Electron Beam System
Authors: Christiansen F.
Published: June 2020

Traditionally, x-ray microprobes, scanning electron microscopes and similar electron microbeam instruments have been designed and built in much the same manner as transmission electron microscopes; that is, as single purpose instruments with provisions for a miltiplicity of attachments to increase their scope. Electron optically these instruments are nearly identical, the only differences being in mechanical restrictions necessary to accommodate spectrometers, specimen stages, light optics, etc. Hence, it appears desirable to modularize an electron microbeam system to provide a variety of instruments, each sharing a common foundation. This then allows the user to convert an instrument from one configuration to another at minimum expense without sacrificing performance and also to readily construct specialized instruments from standard parts. Other advantages of modular construction, both from the builders' and users' standpoint have been discussed previously.
A Compact Field Emission Scanning Electron Microscope
Authors: Welter L. M. , Coates V. J.
Published: June 2020

A compact field emission scanning electron microscope has been developed and modeled after the optical microscope. The new instrument consists of the field emission electron gun, an externally adjustable aperture strip containing four different hole sizes, an electromagnetic single deflection system, an electromagnetic stigmator with independent magnitude and amplitude control, an ion pumped specimen chamber, and a television readout system. No magnetic lenses are used.

The field emission electron gun incorporates an electrode system which simultaneously accelerates and focuses the electrons drawn from a field emission source. Several improvements have been made in the basic gun to provide for higher tip stability and reliability. A unique pumping scheme has been incorporated in the gun to provide tip region pressures in the order of 10-9 Torr and below so that stable field emission can be routinely obtained.
Early Stages of Ordering in Ni3Mo
Authors: Das S. K.
Published: June 2020

The very early stages of ordering in Ni3Mo has been investigated by transmission electron microscopy and diffraction. The short range ordered state in this alloy is similar, hut not identical to that of Ni4Mo. On quenching from 1300°C, in addition to the diffuse peaks at () positions, diffuse peaks also appear at positions very close to where the long range ordered Ni4Mo and Ni2Mo peaks should appear (Fig. 1). This suggests that in the short range ordered state this alloy has clusters of Ni4Mo and Ni2Mo type. Thus the structure in the short range ordered state may consist of not one hut several types of clusters, the structure of which can he different from its long range ordered structure. The word cluster is used here in the general sense of the term to mean groups of atoms of two species A and B.
Transmission Electron Microscopy of Non-Metallic and Geological Materials
Authors: Radcliffe S. V.
Published: June 2020

It is now rather more than a decade since the development of satisfactory techniques for the preparation from bulk metals and alloys of thin foils suitable for examination by transmission electron microscopy. The application of such techniques to substructural problems in these materials and the accompanying developments in diffraction contrast theory has been both intensive and rewarding over this period. However, the application of transmission microscopy to bulk inorganic non-metallic materials, i.e., semi-conductors, ceramics and geological materials, has been much less extensive — especially for the latter. The term ceramics is used broadly here to include all inorganic compounds of metallic and non-metallic elements — i.e., including such diverse materials as alkali halides, glass and concrete — together with the refractory non-metallic elements such as carbon. The present paper is concerned to examine some of the major problems and advances in specimen preparation, observation and analysis in the transmission microscopy of these non-metallic materials and to illustrate selected aspects from current work.
A Preparation of High Resolution Standards for Electron Microscopy. Part II
Authors: Tanaka Akira , Harling David F.
Published: June 2020

In the previous paper, the author reported on a technique for preparing vapor-deposited single crystal films as high resolution standards for electron microscopy. The present paper is intended to describe the preparation of several high resolution standards for dark field microscopy and also to mention some results obtained from these studies. Three preparations were used initially: 1.) Graphitized carbon black, 2.) Epitaxially grown particles of different metals prepared by vapor deposition, and 3.) Particles grown epitaxially on the edge of micro-holes formed in a gold single crystal film.

The authors successfully obtained dark field micrographs demonstrating the 3.4Å lattice spacing of graphitized carbon black and the Au single crystal (111) lattice of 2.35Å. The latter spacing is especially suitable for dark field imaging because of its preparation, as in 3.), above. After the deposited film of Au (001) orientation is prepared at 400°C the substrate temperature is raised, resulting in the formation of many square micro-holes caused by partial evaporation of the Au film.
New Possibilities for Electron Diffraction
Authors: Cowley J. M.
Published: June 2020

Apart from its well-known applications for phase identification and determinations of geometry and orientations in conjunction with bright- and darkfield electron microscopy, electron diffraction has undergone considerable development in the last few years, principally in the direction of a more quantitative use of the technique. Computing methods are available for the calculation of intensities with arbitrary accuracy for well-characterized specimens. Instruments for the accurate measurement of diffracted intensities and for energy analysis have been developed. The major lack, in many cases, is a systematic method for combining data from diffraction and microscopy to determine the crystal morphology, perfection and orientation with sufficient precision. Each of these factors can affect the diffraction intensities strongly. Any one of them may be determined if the others and the crystal structure are known.

In cases for which the specimen characteristics may be defined with sufficient precision, the comparison of intensities calculated by use of n-beam dynamical theory and experimental observation has shown excellent agreement and led to the determination of Fourier coefficients of potential distribution with an accuracy of the order of 0.5 per cent, which is more than comparable with the most precise X-ray measurements.
Enhanced Resolution of Dislocation Imaging at High Voltages
Authors: Osiecki R. , Thomas G.
Published: June 2020

Some results of up to 12 beam contrast calculations for systematic orientations have indicated that high order reflections at high voltages may provide improved dislocation resolution. For example the contrast profiles for dislocations show a decrease in image width for increasing order of reflection (i.e. increasing ḡ·), thus enabling improved resolution of narrow dislocation dissociations and closely spaced dipoles or superdislocations.

This paper provides experimental confirmation that high order systematic reflections do indeed result in an improvement in bright field image resolution, e.g. image widths of dislocations can be reduced by a factor of ~3. The results have been obtained from [001] foils of GaAs semiconducting devices in which dislocations are associated with surface and interfacial defects. In each case the crystal is set at the exact Bragg condition for each reflection along the systematic row being used. The work was done on the Berkeley Hitachi microscope operated at 650 kV.
Diffraction Observations from Very Thin Crystals
Authors: Eichen E. , Melvin C. D. , Plummer H. K.
Published: June 2020

Crystals exhibiting unusual electron diffraction characteristics have been observed in association with cellulose acetate membranes. Subsequently the same type crystals were found on parlodion films which had been stripped from glass slides. These crystals are generally found in conglomerates with random orientation and exhibit hexagonal symmetry in the reciprocal lattice type electron diffraction pattern, as shown in Figures 1 and 2. The most interesting characteristic of these crystals is observed by tilting a crystal through a large angle while observing the diffraction pattern. The diffraction pattern spreads perpendicular to the tilt axis so that it becomes eliptical rather than circular in symmetry and the primary spots observed at 0° tilt remain in the diffraction pattern through at least 45° of tilt, as shown in Figures 2 and 3. The spreading of the diffraction pattern seems to follow the inverse cosine of the tilt angle when tilting from +45° to -30°, and the off axis spots increase in structure with tilt.
Direct Observation of a New Coherent Precipitate in Commercial Nickel-Base Alloys
Authors: Doherty J. E. , Fornwalt D. E. , Kear B. H.
Published: June 2020

A nickel-base superalloy consists essentially of a Ni/Cr solid solution γ matrix strengthened by the precipitation of the γ' phase, Ni3(Al,Ti). In commercial alloys, transition metal additions are made for solid solution strengthening and C, B and Zr are added to improve grain boundary properties. The carbon reacts to form a variety of carbide phases. (MC, M23C6, M6C and M7C3) depending on composition and heat treatment whereas the B normally reacts to form M3B2-type diborides. In what follows it is shown that in addition to these basic reactions, C and B together can combine with Ti and Nb to form a borocarbide phase. Evidence has also been found for the precipitation of γ within the interdendritic massive γ'.