bluuebunny/crossref_metadata_2025 huggingface dataset:
Ultra High Vacuum Scanning Electron Microscopy of Directly Deposited Metallic Films
Authors: Ballantyne J. P. , Dix C. , Nixon W. C.
Published: June 2020

A basic scanning electron microscope of similar construction to that described by Pease and Nixon has been modified for ultra high vacuum by using a special stainless steel specimen chamber. The final aperture of the electron optical column is also the differential pumping aperture separating the lens and scan coil region from the specimen chamber. Recent further refinement has given a measured vacuum in the specimen region of 1 x 10-10 torr after baking and day to day operation at 10-8 torr. The specimen stage stability and the electron optical performance permit an electron probe size of 200-300 A at these vacuum levels. The main column is pumped to 10-6 torr.

This improved vacuum performance is necessary for depositing and viewing thin metal films as there is no residual contamination and no effect of partial pressures of gases to influence the main reaction. Both silver and tin films have been deposited from halide compounds with a resulting metal thickness of about one micron giving reasonable conductivity. The substrate is silicon of integrated circuit quality.
Retention of 3-Dimensional Contours by Replicas of Freeze-Fracturcd Specimens
Authors: Steere Russell L.
Published: June 2020

Electron micrographs of complementary replicas prepared by either the freeze-fracture or the freeze-etch procedure have often been disappointing. One replica may look excellent whereas the complement, produced simultaneously in the same system, may look worthless. At least part of this complication may be explained by the fact that these replicas retain much of the 3-dimensional contours of the replicated ice surface when dried on a Formvar film. If the desired part of such a replica is oriented in the microscope in such a position that it is vertical to the beam it usually looks good. However, if the desired area happens to be other than vertical to the electron beam, the resultant image may be somewhat distorted if the angle is slight, or may be completely obscurred by electron scattering if the angle is steep.

Dog cardiac muscle perfused with glutaraldehyde, washed in distilled water, then transferred to 30% glycerol (furnished by Dr. Joaquim Sommer, Duke Univ.) was freeze-fractured at -196° in a Denton DFE-2 Freeze-Etch Unit, shadowed with Pt from a C point, and replicated with C. The replicas were cleaned of biological remains in chromic acid cleaning solution, then mounted on Formvar support films.
Peroxidase Localization in Hartmanella Trophozoites
Authors: Childs George E. , Miller Joseph H.
Published: June 2020

Biochemical and differential centrifugation studies have demonstrated that the oxidative enzymes of Acanthamoeba sp. are localized in mitochondria and peroxisomes (microbodies). Although hartmanellid amoebae have been the subject of several electron microscopic studies, peroxisomes have not been described from these organisms or other protozoa. Cytochemical tests employing diaminobenzidine-tetra HCl (DAB) and hydrogen peroxide were used for the ultrastructural localization of peroxidases of trophozoites of Hartmanella sp. (A-l, Culbertson), a pathogenic strain grown in axenic cultures of trypticase soy broth.
The Nature of Rapidly Extracted Phycocyanin from the Blue-Green Alga Plectonema Boryanum
Authors: Kessel M. , MacColl R.
Published: June 2020

The major protein of the blue-green algae is the biliprotein, C-phycocyanin (Amax = 620 nm), which is presumed to exist in the cell in the form of distinct aggregates called phycobilisomes. The self-assembly of C-phycocyanin from monomer to hexamer has been extensively studied, but the proposed next step in the assembly of a phycobilisome, the formation of 19s subunits, is completely unknown. We have used electron microscopy and analytical ultracentrifugation in combination with a method for rapid and gentle extraction of phycocyanin to study its subunit structure and assembly.

To establish the existence of phycobilisomes, cells of P. boryanum in the log phase of growth, growing at a light intensity of 200 foot candles, were fixed in 2% glutaraldehyde in 0.1M cacodylate buffer, pH 7.0, for 3 hours at 4°C. The cells were post-fixed in 1% OsO4 in the same buffer overnight. Material was stained for 1 hour in uranyl acetate (1%), dehydrated and embedded in araldite and examined in thin sections.
High Voltage Electron Microscopy of Poxvirus Nucleoid Material
Authors: Grimley P. M.
Published: June 2020

Appearance of an eccentric nucleoid within developing poxvirus envelopes is the first ultrastructural evidence of core differentiation. Subsequently, the nucleoid elongates and is flanked by lenticular densities known as lateral bodies. When mature, it collapses into a biconcave form. In ultrathin sections, the eccentric nucleoid usually appears compact; although in the elongate stage central spaces may be apparent. Normally, the stages of poxvirus maturation are asynchronous and difficult to examine in order. Treatment of infected cells with rifampin provides a useful experimental approach for examining the development of nucleoid material.

HeLa cells were treated with rifampin (100µg/ml) during an 8 hr. infection with vaccinia virus. Rifampin interrupts vaccinia morphogenesis at a stage prior to the formation of coated envelopes, and membranous precursors of envelopes accumulate. When the drug is washed out, large numbers of virus envelopes form simoultaneously (Fig. 1).
Physical Properties of Isolated Perfused Renal Tubular Basement Membranes
Authors: Grantham Jared , Welling Larry
Published: June 2020

In the course of urine formation in mammalian kidneys over 90% of the glomerular filtrate moves from the tubular lumen into the peritubular capillaries by both active and passive transport mechanisms. In all of the morphologically distinct segments of the renal tubule, e.g. proximal tubule, loop of Henle and distal nephron, the tubular absorbate passes through a basement membrane which rests against the basilar surface of the epithelial cells. The basement membrane is in a strategic location to affect the geometry of the tubules and to influence the movement of tubular absorbate into the renal interstitium. In the present studies we have determined directly some of the mechanical and permeability characteristics of tubular basement membranes.
Nucleated and Anucleated Spermatozoa in Inseminated Female Silkworms
Authors: Friedländer M.
Published: June 2020

The silkworm Bombyx mori, like other moths, produces both typical-haploid and atypical-anucleate spermatozoa. Typical spermatogenesis takes place in the larva and ceases in the pupa, while atypical spermatogenesis starts in the pupa and continues in the adult. Typical spermatozoa fertilize the eggs. The function of the atypical spermatozoa is unknown and even their presence in the inseminated female is uncertain.

Genital ducts of inseminated female silkworms were studied to find out whether the atypical spermatozoa reach the female, and if they do, to determine their fate. The changes in the spermatozoa during the process of capacitation were also studied. Ducts were fixed in 1.7% glutaraldehyde in 0.1M phosphate buffer, pH 7.3, refixed in OSO4, embeded in Epon, and examined.
Useful Resolution Standards for Freeze-Cleave and Etch Replication Techniques
Authors: McNutt N. Scott , Weinstein Ronald S.
Published: June 2020

Kreutziger has noted that obscuration of hexagonal arrays of depressions (pits) in the inwardly-directed face (face B) of membranes at the nexus can be a result of specimen surface contamination and that the visualization of these pits can be used as a quality test for freeze-cleave and etch replicas. During our study of nexus membranes, we observed that pits in nexus face B can be observed in replicas which by other criteria would be judged as quite crude. We now suggest two images which can be used conveniently as resolution standards and which have been seen only in high quality replicas.

Rabbit and human erythrocytes were isolated from fresh blood by differential centrifugation and glycerinated to 20% glycerol in 0.9% NaCl. Yeast cells (Saccharomyces cerevisiae) were grown on Sabaroud's medium at room temperature, harvested, and glycerinated to 10% glycerol in 0.9% NaCl. Mouse cardiac muscle was fixed in 1% glutaraldehyde-0.1M cacodylate buffer, pH 7, for 15 minutes and then glycerinated to 10% or 20% glycerol in 0.9% NaCl. Erythrocytes or yeasts were centrifuged into a loose pellet which was used as a mounting support matrix around specimens of cardiac muscle on the specimen holder of an MGH-Type II simple cold block freeze-cleave device.
High Voltage Electron Microscopy in Europe
Authors: Cosslett V. Ellis
Published: June 2020

There are two well established high voltage microscopy laboratories in Europe, several new installations and a few experimental instruments still in the development stage. The latest information about each of these projects will be presented.

C.N.R.S. Laboratory, Toulouse, France: The 3 MV microscope is in operation. In initial tests, micrographs of 5 μm stainless steel have been obtained at 2 MV. The HV generator and the lens current systems have been described, as well as the microscope itself. Many studies, mainly of physical aspects of high voltage microscopy, have been made with the 1.5 MV instrument.

Cavendish Laboratory, Cambridge, England: A great variety of research projects are under investigation on the “home-built” 750 kV microscope, in biology as well as in metallurgy and polymer science. Quantitative studies have been made of energy loss in typical materials, and of the sensitivity and resolution of viewing screens and photographic emulsions. Special stages and other apparatus have been developed.
Herpestype Virus and Type C Particles in Spontaneous Equine Lymphoma
Authors: Maruyama K. , Swearingen G. R. , Dmochowski L. , Jardine J. H. , Joiner G. N.
Published: June 2020

Herpestype and type C virus particles are known to produce tumors in animals of certain species, and to be present in a variety of human tissues. Similar particles were found in a horse lymphoma.

Electron microscope study was carried out on a tumorous prescapular lymph node from an adult female horse with spontaneous lymphoma. Lymph node cells grown in vitro for a total of 105 days (6th passage) were also studied. The lymph node was infiltrated by blastic cells of reticulum cell type and of lymphoblast type. No virus particles were found in the original lymph node. The cultured cells have a large cytoplasm with well developed rough endoplasmic reticulum and Golgi's apparatus, and an indented nucleus with marginated chromatin. Occasionally, intranuclear fibrous structures were observed. Elongated nuclear protrusion were frequently seen.
Observations on the Fine Structure of Metastatic Malignant Melanoma
Authors: Mackay Bruce , Lichtiger Benjamin , F. Tessmer Carl
Published: June 2020

The electron microscope is used as a routine supplement to conventional light microscopy in tumor diagnosis at this hospital. One of the most difficult diagnostic problems faced by the surgical pathologist, and the most frequent, is the occurrence of a metastatic tumor which is insufficiently well differentiated to permit classification by light microscopy, and where clinical and other investigations have failed to demonstrate a primary site. In such a situation, malignant melanoma must always be considered in the differential diagnosis. We have therefore found it necessary to study the fine structure of a series of melanomas in order to determine the range of morphologic appearances that the tumor cells may assume in electron micrographs, and to establish criteria for diagnosis.
Effect of Improved ThO2 Particle Dispersion in Nickel on High-Temperature Strength
Authors: Kimmel E. R. , Anthony H. L. , Scheithauer W.
Published: June 2020

The strengthening effect at high temperature produced by a dispersed oxide phase in a metal matrix is seemingly dependent on at least two major contributors: oxide particle size and spatial distribution, and stability of the worked microstructure. These two are strongly interrelated. The stability of the microstructure is produced by polygonization of the worked structure forming low angle cell boundaries which become anchored by the dispersed oxide particles. The effect of the particles on strength is therefore twofold, in that they stabilize the worked microstructure and also hinder dislocation motion during loading.
On the Fine Structure of Carbon Fibers
Authors: Khoury F.A. , Boucher E.A.
Published: June 2020

In accord with Johnson and Tyson readily discernible dark (extinction) bands in bright field images and bright (intensity) bands in (002) dark field images were observed in fragments as well as the ends of broken commercial polyacrylonitrile based graphitized carbon fibers (tensile strength = 1.78 × 109 Nm-2, tensile modulus = 3.48 × 1011 Nm-2; 6.895 × 103 Nm-2 = 1 psi). The bands are oriented at right angles to the fiber axis. Denoting the band dimensions parallel and perpendicular to the fiber axis direction as Bx and By respectively, it was found that Bx was in the range ∼1.5 nm - 7.0 nm whereas By was in the range ∼3.0 nm - 25.0 nm. The ratio Bx/By for individual bands varied in the range 1/8 to one but was usually less than one.
Hydration Chamber for Jeolco 200 Kv Microscope
Authors: Matricardi V. R. , Hausner G. G. , Parsons D. F.
Published: June 2020

In order to observe room temperature hydrated specimens in an electron microscope, the following conditions should be satisfied:

The specimen should be surrounded by water vapor as close as possible to the equilibrium vapor pressure corresponding to the temperature of the specimen.

The specimen grid should be inserted, focused and photo graphed in the shortest possible time in order to minimize dehydration.

The full area of the specimen grid should be visible in order to minimize the number of changes of specimen required.

There should be no pressure gradient across the grid so that specimens can be straddled across holes.

Leakage of water vapor to the column should be minimized.
Interfacial Dislocations in (111) Ag-Cu Bilayers
Authors: Homg C. T. , Vook R. W.
Published: June 2020

Smooth (111) single crystal Cu films (1200Å) were evaporated on NaCl/mica in an ultra-high vacuum RHEED systemI (base pressure ≤1×10−9 torr) The total residual gas pressure during Cu evaporation was less than 1×10−8 torr. These Cu films served as substrates for thin epitaxial monolayer Ag growth ranging in thickness from 1Å to 20Å, as measured by a quartz thickness monitor. These Ag-Cu bilayers were formed and examined in-situ in the RHEED system.

The unusual RHEED patterns first re orted by Gradmann and Krause were observed in the present work up to l0Å of Ag. Beyond 10Å, only Ag and Cu lines plus double diffraction effects were detected. A typical example of the former is given in Fig. 1. The pattern was previously interpreted as due to a two dimensional grid of interfacial dislocations.
Microstructures of the Superplastic Al-Zn Eutectoid Deformed at Constant Strain Rates
Authors: Franti G. W.
Published: June 2020

Much of the work on the deformation behavior of superplastic alloys has been carried out using constant velocity testing. In constant velocity testing, the true strain rate is continuously decreasing with strain and the effect of the strain based on the deformation behavior is difficult to assess.

In the present study, an Instron tensile testing machine (Model TT-CM-L) was modified with the addition of a small analog computer to yield true constant strain rates in the range of 10−4 min.−1 to 10 min.−1

The Al-Zn eutectoid was cast from the pure metals and hotrolled to a 75% reduction in area. Tensile samples of 0.475 cm gauge diameter and 3.50 cm guage length were homogenized at 375°C for three hours and ice-water quenched. Prior to testing, samples were annealed at 250°C for three hours to yield an average grain size of one micron.
Reconstruction of Objects from their Projections Using Orthogonal Functions
Authors: Zeitler Elrnar
Published: June 2020

Considering any finite three-dimensional object, a “projection” is here defined as a two-dimensional representation of the object's mass per unit area on a plane normal to a given projection axis, here taken as they-axis. Since the object can be seen as being built from parallel, thin slices, the relation between object structure and its projection can be reduced by one dimension. It is assumed that an electron microscope equipped with a tilting stage records the projection

Where the object has a spatial density distribution p(r,ϕ) within a limiting radius taken to be unity, and the stage is tilted by an angle 9 with respect to the x-axis of the recording plane.
Ultrastructural Localization of 5'-Nucleotide Phosphodiesterase in Rat Liver and Hepatoma
Authors: Tsou K. C. , Gupta P. D.
Published: June 2020

The difficulty in developing a 5'-nucleotide phosphodiesterase cytochemical method suitable for electron microscope is well-known. Unlike ATPase or 5′-nucleotidase, where the insoluble lead phosphate can be used successfully to localize the hydrolytic product, both products from enzymatic hydrolysis of a 5′-nucleotide phosphodiester are soluble. Earlier, an indigogenic substrate, 5′-(5-iodo-3-indolyl)-thymidine phosphodiester was used to yield an insoluble 5,5′-di-iodoindigo. This method was ultimately improved with the use of a mixture of 5′-(5-iodo-3-indolyl)-5-fluorodeoxyuridine (5′-IIp-FUdR), and 5′-(5-nitro-3-indolyl)-5-fluorodeoxyuridine (5′- N02lp-FUdR), which produced an insoluble electron-dense indigo complex. The present report demonstrates its usefulness for the ultrastructural localization of this enzyme in rat liver and hepatoma.
Origin of Hepatic Nuclear Inclusion Bodies
Authors: Zaki F. G. , Greenlee J. A. , Keysser C. H.
Published: June 2020

Nuclear inclusion bodies seen in human liver cells may appear in light microscopy as deposits of fat or glycogen resulting from various diseases such as diabetes, hepatitis, cholestasis or glycogen storage disease. These deposits have been also encountered in experimental liver injury and in our animals subjected to nutritional deficiencies, drug intoxication and hepatocarcinogens. Sometimes these deposits fail to demonstrate the presence of fat or glycogen and show PAS negative reaction. Such deposits are considered as viral products.

Electron microscopic studies of these nuclei revealed that such inclusion bodies were not products of the nucleus per se but were mere segments of endoplasmic reticulum trapped inside invaginating nuclei (Fig. 1-3).
Scanning Electron Microscopy of Vascular Casts For the Study of Vessel Connections in a Complex Vascular Bed - The Trout Gill
Authors: Gannona B.J. , Campbell Graeme , Randall D.J.
Published: June 2020

The microcirculation of fish gills has been investigated by light microscopic study of sample or serial sections, transmission electronmicroscopy, and microscopic study of intact Blood or ink filled gill filaments; it is considered to consist of a series of respiratory pathways and non-respiratory shunts.

However, reconstruction of a complex 3 dimensional structure from 2. dimensional information, as is available from section study, is fraught with difficulty, especially in establishing connections between micro-vessels. Also, investigation of intact specimens is hampered by poor resolution and inadequate depth perception into the tissue.

Perfusion of the microcirculation with a liquid plastic mixture which will polymerise in situ produces a mechanically selfsupporting object, after tissue removal, for study with the S.E.M; this approach permits direct examination of the microvasculature in three dimensions.
Critical Point Drying of Freeze-Fractured Tissue For Scanning Electron Microscopy
Authors: Humphreys Walter J. , Spurlock Ben O. , Johnson Janet S.
Published: June 2020

The critical point method eliminates distortion that might have been caused by surface tension during drying of specimens being prepared for scanning electron microscopy. Such preparations can be made rapidly and routinely, and the structural fidelity of surfaces of cells and tissues thus prepared is excellent. But attempts to look inside the tissues or cells with the scanning electron microscope have been less successful. Critical point dried tissue can be broken or cut, and the exposed surface viewed. But plastic deformation of the exposed surface structures caused by the cutting or breaking severely limits the usefulness of this approach. Plastic deformation is minimized when tissue is freeze-fractured to expose internal surfaces, and the water (ice) can be sublimed away from small fragments of tissue without surface tension distortion by freeze-drying the specimen in a vacuum. But freeze damage, resulting mainly from ice crystal formation, is very difficult to avoid.
Nucleolus-Like Cytoplasmic Body in a Pyramidal Cortical Neuron in a Normal Cat
Authors: Feria-Velasco Alfredo
Published: June 2020

Cytoplasmic bodies resembling nucleolus have been reported in the literature to be present in various types of cells, specially in nerve cells. This type of structure has been frequently observed in nerve cells of dorsal nucleus of the vagus and in some hypothalamic nuclei. There is only one communication as to the occurrence of a nucleolus-like structure in cortical nerve cells (entorhinal cortex) of mice previously injected with puromycin intracerebrally.

In the present work, it is reported the presence of a nucleolus-like body in the cytoplasm of a motor cortical pyramidal nerve cell of a normal cat. The animal was not receiving any type of treatment which would interfere with protein synthesis. Its behavior and electronencephalographic records were within normal limits.
Fine Structural Localization of Intravenously Injected Cytochrome C in the Porcine Choroid Plexus
Authors: Davis D. A. , Milhorat T. H. , Lloyd B. J.
Published: June 2020

In the continuing search for suitable markers that can be used for examining mechanisms of cerebrospinal fluid (CSF) formation, we were recently led to a study of cytochrome c. This hemo-chromogen has two primary advantages as a marker: 1. It is g. considerably smaller protein (molecular wt. 13,000, radius 15 Å) than ferritin (molecular wt. 400,000, radius 5 Å) or horseradish peroxidase (molecular wt. 40,000, radius 25-30Å) ; 2. It is easily visualized by electron microscopy after reaction with 3,3'-diaminobenzidine (dab).

Cytochrome c (Cal Biochem Grade A) was administered intravenously to pigs (7-9 kg. in wt.) in doses of 25-30 mg./100 g. wt.
Membrane Junctions Between Neurons in the Brain of the Housefly, Musca Domestica
Authors: Sohal R. S. , Sharma S. P.
Published: June 2020

Invertebrate organisms are increasingly being employed for basic neurophysiological studies, however, the cytological features of the invertebrate brain are not very well understood. The present report describes the interneuronal membrane junctions in the brain of the housefly, Musca domestica. Soma of the neurons in Musca brain are located on the periphery of the brain and are completely surrounded by glioplasm which precludes theexistence of synaptic junctionsl. Synaptic sites occur in the neuropil mass which constitutes the core of the brain and is formed by.the intermingling of axons and glial processes. Glial processes only partially surround the axons.
Growth instability of polyethyleneterephthalate oligomer crystals
Authors: Perovic Aleksandra
Published: June 2020

The growth forms of crystals have been an ongoing subject of interest to scientists and an enormous amount of factual material has been accumulated and a comprehensive theory of crystal growth has evolved. One of the most interesting aspects of the growth of regular, polyhedral crystals is that of relating to the establishments of the stability conditions governing the transformation of regular crystal shapes into hopper, skeletal or dendritic shapes.

The growth features of instability conditions have been observed in hexagonal plate-like oligomer crystals in polyethyleneterephthalate forming on the surface of the film during annealing. Figures 1(a) and (b) represent scanning electronmicrographs of oligomer crystals developed on the surface of polyethyleneterephthalate film during heat treatment. The hexagonal plates have smooth basal faces.
High-resolution TEM and analytical study of second-phase particles in Al2O3
Authors: Morrissey K. J. , Kouh Y. , Carter C. B.
Published: June 2020

The influence of additives such as MgO, NiO, and ZrO2 and impurities such as Na, K, and Ca on the sintering of alumina compacts has been the focus of a considerable amount of research. Since these additives affect compact density and grain size it is of interest to determine the behavior of the elements during processing. That is, it is important to know whether Ca and Mg segregate to grain boundaries or are located in the second-phase particles. Current results suggest that Ca is found uniformly at the grain boundaries and that Mg is accommodated in the second-phase particles.

The present investigation is concerned with identifying second-phase particles in different commercially-produced Al2O3 compacts and studying both their structure and composition. Preliminary results have been discussed previously. The investigation has dealt mainly with two different alumina compacts. One compact was prepared from an initial powder containing 0.25% MgO, a small amount of intentionally added Ni, and was prepared by hot pressing.
Microstructure of highly reactive submicrometer TiB2 powders
Authors: Angelini P. , Lehman G. L. , Brynestad J.
Published: June 2020

Research has begun involving the pressing and evaluation of TiB2 compacts produced from submicrometer-sized TiB2 powder. Among the advantages offered by the use of such starting powder are that sintering and densification may be performed at relatively low temperatures (1400°C), limited grain growth may occur (<1 μm grains), and densification may proceed without the need of binder phases. However, one of the difficulties with the use of such powder is that it oxidizes rapidly when exposed to air. Thus processing may need to be performed under inert conditions.

Powders analyzed in this study included those exposed to air, to water, and only to an inert atmosphere (He). Large particle size material can tolerate exposure to air, but small particle size powder must first be exposed to H2O before being exposed to air. This exposure can modify the as-produced powder either by oxidation or dissolution processes.
Lithography below 100 nm
Authors: Jackel L. D.
Published: June 2020

Most production electron beam lithography systems can pattern minimum features a few tenths of a micron across. Linewidth in these systems is usually limited by the quality of the exposing beam and by electron scattering in the resist and substrate. By using a smaller spot along with exposure techniques that minimize scattering and its effects, laboratory e-beam lithography systems can now make features hundredths of a micron wide on standard substrate material. This talk will outline sane of these high- resolution e-beam lithography techniques.

We first consider parameters of the exposure process that limit resolution in organic resists. For concreteness suppose that we have a “positive” resist in which exposing electrons break bonds in the resist molecules thus increasing the exposed resist's solubility in a developer. Ihe attainable resolution is obviously limited by the overall width of the exposing beam, but the spatial distribution of the beam intensity, the beam “profile” , also contributes to the resolution. Depending on the local electron dose, more or less resist bonds are broken resulting in slower or faster dissolution in the developer.
Transmission electron microscopic studies of phase transformations in Ti-H and Ti-6A1-4V alloys
Authors: O'Neal J. E. , Sastry S. M. L.
Published: June 2020

At 600°C, hydrogen readily combines with titanium and has a solubility in excess of 3 wt% (60 at.%). This addition of hydrogen reduces the betatransus temperature and stabilizes the more-open body-centered-cubic phase of titanium. This is a reversible process, however—the Ti-H solid solution formed by annealing Ti at 600°C in a hydrogen atmosphere can be converted to hydrogen-free titanium by subsequent annealing in a vacuum. This heat treatment, termed “hydrovac”, produces considerable grain refinement in titanium alloys. Hydrovac processing has beneficial effects on titanium forging, superplastic forming/diffusion bonding, and titanium powder consolidation. This study was made to determine the morphological and phase changes associated with the various hydrovac processing steps for Ti and Ti-6A1-4V alloy.
Evaluation of single-electron movies of glutamine synthetase molecules
Authors: Kunath W. , Zeitler E. , Kessel M.
Published: June 2020

The features of digital recording of a continuous series (movie) of singleelectron TV frames are reported. The technique is used to investigate structural changes in negatively stained glutamine synthetase molecules (GS) during electron irradiation and, as an ultimate goal, to look for the molecules' “undamaged” structure, say, after a 1 e/Å2 dose.

The TV frame of fig. la shows an image of 5 glutamine synthetase molecules exposed to 1/150 e/Å2. Every single electron is recorded as a unit signal in a 256 ×256 field. The extremely low exposure of a single TV frame as dictated by the single-electron recording device including the electron microscope requires accumulation of 150 TV frames into one frame (fig. lb) thus achieving a reasonable compromise between the conflicting aspects of exposure time per frame of 3 sec. vs. object drift of less than 1 Å, and exposure per frame of 1 e/Å2 vs. rate of structural damage.
Development of an electron energy loss spectrometer (H-8020) for 200kV ATEM
Authors: Kobayashi H. , Isakozawa S. , Kamimura S. , Okamura S.
Published: June 2020

We have developed an electron energy loss spectrometer (H-8020) for a 200kV electron microscope (H-800).

(Fig. 1) This spectrometer utilizes a sectorQtype electro-magnet with a radius of 132 mm and a deflection angle of 90°. The magnet allows 3-dimensional beam focus. There is an alignment coil and stigmator built-in at the entrance of the magnet to ensure good resolution. At the outlet of the magnet, there is a pair of electrodes. An RF voltage, which is synchronized with a rockin- amplifier, is applied as a carrier wave across the electrodes. Thus, electron energy loss spectrum is detected in a differentiated form so that back ground noise of the spectrum is eliminated and it permits elemental mapping image of a specified element. In addition, we have incorporated a CRT for monitoring spectrum and such new functions as auto main peak search, auto gain control for improved overall operation.

Fig. 2 is an example of energy resolution of aluminum evaporated film. It shows 2eV resolution at 200kV.

Fig. 3 is an example of boron nitride (BN). It shows fine structures at the edge of B-K peak.
Development of an automatic electron diffraction pattern analyzing system
Authors: Moriguchi S. , Shinkawa T. , Watanabe E. , Makita Y. , Sakurai S. , Kokubo Y. , Tokiwai M.
Published: June 2020

The electron diffraction pattern has information on the crystal structure of samples, such as the crystal system, lattice constants and the orientation for the incident beam. Material can be identified by measuring the above characteristics and, in general principle by measuring their accurate lattice spacings. However, this measurement requires a lot of time and fundamental knowledge of the crystal structure.

The present automatic analyzing system of the electron diffraction pattern makes the analysis ease. The outline of this system is described in this paper.

The hardware system consists roughly of three components; a low-light-level TV device called the image carrier, a frame memory, and a minicomputer. The image carrier transforms the image formed on the flourescent screen of a transmission electron microscope (TEM) into video signals. The frame memory is provided with a memory plane of 512 x 512 pixels, each having 256 gray levels. It digitaizes video signals of the image and stores them in itself.
Selective contrast in images of crystalline cytochrome oxidase dimers
Authors: Frey T. G. , Costello M. J. , Reardon J. E. , Frey P. A.
Published: June 2020

Vesicle crystals of cytochrome oxidase dimers embedded in the phospholipid bilayer of a collapsed vesicle are produced when beef heart mitochondria are treated with Triton detergents. The crystals have the symmetry of plane group p22121 with unit cell dimensions of a=95 A, b=125 A, and c=210 A. The molecules protrude 60 A beyond the lipid bilayer on the inside of the vesicle, but very little beyond the bilayer on the outside. Decoration of crys- stals with subunit-specific antibodies identified the outside surface of the vesicle crystals as corresponding to the M-side (matrix) of the inner mitochondrial membrane and the inside surface as the C-side (cytoplasmic).

We have used various methods of specimen preparation to selectively image different regions of the dimer crystals in order to correlate the structure of dimers with that of 'Y'-shaped monomers. Electron micrographs of negatively stained specimens (Fig. 1a, 2a) give a two-dimensional projection of the three-dimensional stain replica of the entire structure.
Molecular structures of isolated lung basement membranes in man
Authors: Lee Y.S. , Juan S.Y. , Chang C.H.
Published: June 2020

Basement membranes, the extracellular structures close to the plasma membranes, have been suggested to have differences in chemical and molecular structures to serve a wide variety of functional roles in different tissues. Although the chemical compositions of the basement membranes are well known the molecular organization within the membrane matrices remains unclear. Recently, several investigators have proposed different models for the organization of collagen molecules in the basement membranes. In fact, these models are actually unable to represent the molecular structures within the native basement membranes. Since there has been no direct knowledge regarding the molecular structures in the lung basement membranes the purpose of the present investigation is to characterize the internal structures of the isolated lung basement membranes at the molecular level by the conventional electron microscope technique.

This study was carried out on human lung specimens which were obtained from 6 autopsy patients.
Microtubule polarity and spindle function
Authors: Euteneuer Ursula
Published: June 2020

The idea that microtubule (MT) polarity is important for spindle function was first proposed more than a decade ago. However, it was not until 1974 that this idea could be put to a direct test. The identification of methods for MT polymerization in vitro made it possible to use flagella and cilia as seeds for purified brain tubulin; it was demonstrated that under given conditions one end of the MT grows at a faster rate than the other. The two different ends were designated 'plus' and 'minus' end. Subsequently efforts were made to determine the polarity of spindle MTs with the help of these rate measurements. Mitotic centers as well as chromosomes were isolated and the rate of MT growth from these initiation sites was compared to the rates of MT growth from the two ends of flagella or cilia. The results from these experiments revealed that MTs were growing at a fast rate from both structures, suggesting that the plus ends of aster and kinetochore MTs are distal to these sites.
X-ray microanalysis of embryonic tissue exposed to lead
Authors: Kuettel Michael R.
Published: June 2020

Developmental malformations of the cardiovascular system are relatively common and well known. Less well known is the fact that this system may play an important role in the genesis of non-cardiovascular defects. Specifically, pilot studies indicated that caudal malformations in lead treated chick embryos are directly caused by a preceding cardiovascular abnormality; the presence of a large, blood filled caudal hematoma. These hematomas develop 16 to 24 hours after 20 μl of a lead nitrate solution (10 mM) is administered subgerminally on the second day of incubation. Small breaks and ultrastructural changes within the caudal embryonic dorsal aorta were observed as early as 4 hours after treatment. As these hematomas expand, they compress the surrounding soft embryonic tissues, destroying both the spatial relationships between tissues and the integrity of the tissues themselves. Pyknosis follows rapidly, and ultimately the dead or dying tissues and the hematoma itself are resorbed leading to a condition known as rumplessness (caudal dysplasia in humans). Within a short time of the formation of the initial hematoma, a tissue deficit is the only sign that a cardiovascular anomaly has occured.
Acute response of lung parenchyma to volcanic ash
Authors: Dodson R.F. , Akematsu T. , Williams M.G. , O'Sullivan M.F. , Hurst G. A.
Published: June 2020

The eruption of Mt. St. Helens on May 18, 1980, resulted in a concentrated short-term exposure for a large segment of the population of eastern Washington, northern Idaho, and western Montana. Samples were collected from all three regions and the respirable size particles (⋜0.6μ) were separated and analyzed. The predominance of the respirable size fraction was found by X-ray energy dispersive analysis to be alumino silicates. A homogeneous preparation was intratracheally injected into young adult guinea pigs. The dose given the animals consisted of 52.5 mg in saline. This dose provided a short-term heavy exposure setting similar to that of the populus. At the end of the selected post-injection intervals of either 2 or 4 hours or 1 through 7 days, the animals were sacrificed by vascular perfusion through the right ventricle.

Embedded tissue samples were reviewed at the light microscopy level and selected fields were thin sectioned for transmission electron microscopy and scanning transmission electron microscopy (correlated with X-ray energy dispersive analysis). The EM was carried out on a JEOL 100CX TEMSCAN.
Structural alterations in early myocardial anoxia
Authors: Ashraf M. , Rahamatulla P.M.
Published: June 2020

Occlusion of a major coronary artery in a canine results in heterogenous infarct that makes the study of sequential subcellular changes on a temporal basis difficult. In this investigation, global anoxia was induced in isolated rat hearts in order to produce uniform anoxic changes. The hearts removed from Sprague-Dawley rats were perfused with Krebs-Henseleit (KH) medium saturated with 95% O2, 5% CO2 for 30 minutes (control). The ingredients of the anoxic medium were the same except glucose was replaced by mannitol to adjust osmolarity. The anoxic medium was bubbled with 95% N2 and 5% CO2. The perfusion was changed to anoxic medium for 5, 10, 15, 20, 25, and 30 minutes. Six rats were used for each time interval. At the end of experiments, the hearts were perfused with 3% buffered glutaraldehyde, pH 7.3, postfixed with 1% buffered osmium tetroxide for 1 1/2 hours, dehydrated in ethanol and processed for electron microscopy.
Presence of antibody in virus-infected brain cells of SSPE ferrets
Authors: Brown Hannah R. , Donato Tammy L. , Thormar Halldor
Published: June 2020

Measles virus specific immunoglobulin G (IgG) has been found in the brains of patients with subacute sclerosing panencephalitis (SSPE), a slowly progressing disease of the central nervous system (CNS) in children. IgG/albumin ratios indicate that the antibodies are synthesized within the CNS. Using the ferret as an animal model to study the disease, we have been attempting to localize the Ig's in the brains of animals inoculated with a cell associated strain of SSPE. In an earlier report, preliminary results using Protein A conjugated to horseradish peroxidase (PrAPx) (Dynatech Diagnostics Inc., South Windham, ME.) to detect antibodies revealed the presence of immunoglobulin mainly in antibody-producing plasma cells in inflammatory lesions and not in infected brain cells.

In the present experiment we studied the brain of an SSPE ferret with neutralizing antibody titers of 1:1024 in serum and 1:512 in CSF at time of sacrifice 7 months after i.c. inoculation with SSPE measles virus-infected cells. The animal was perfused with saline and portions of the brain and spinal cord were immersed in periodate-lysine-paraformaldehyde (P-L-P) fixative. The ferret was not perfused with fixative because parts of the brain were used for virus isolation.
Auger Electron Spectroscopy with the Scanning Electron Microscope
Authors: Hart Raymond K.
Published: June 2020

Various SEM-AES combinations have been described in the literature during the past six years. All these instruments, with one exception, were dry pumped and capable of operating at pressures below 10-7torr. The equipment described herein, see Fig.1, is a modified ULTRASCAN SEM with an Auger-electron analysis system from Physical Electronics Industries (PHI): it is also dry pumped to the low 10-7torr range.

The electron optical column uses two electromagnetic lenses instead of the original three, and with a 200 micron objective aperture it delivers a maximum of 0.6 to 0.8 x 10-8A at the specimen. At the short working distance (1.2 cm) the spatial resolution is between 70 and 80 nm, while at the longer working distance (3.2 cm) the resolution is about 100 nm. The scintillator assembly was transposed to the right side of the specimen chamber so that a PHI small cylindrical-mirror velocity analyzer, with bellows extension could be mounted diametrically opposite the scintillator.
Lattice Imaging of Grain Boundaries in Ceramics
Authors: Clarke D. R. , Thomas G.
Published: June 2020

Grain boundaries have long held a special significance to ceramicists. In part, this has been because it has been impossible until now to actually observe the boundaries themselves. Just as important, however, is the fact that the grain boundaries and their environs have a determing influence on both the mechanisms by which powder compaction occurs during fabrication, and on the overall mechanical properties of the material. One area where the grain boundary plays a particularly important role is in the high temperature strength of hot-pressed ceramics. This is a subject of current interest as extensive efforts are being made to develop ceramics, such as silicon nitride alloys, for high temperature structural applications. In this presentation we describe how the techniques of lattice fringe imaging have made it possible to study the grain boundaries in a number of refractory ceramics, and illustrate some of the findings.
Lattice Imaging of Twin, Lath and α/Martensite Boundaries in Duplex Low Carbon Steels
Authors: Koo J. Y. , Thomas G.
Published: June 2020

High resolution electron microscopy has been shown to give new information on defects(1) and phase transformations in solids (2,3). In a continuing program of lattice fringe imaging of alloys, we have applied this technique to the martensitic transformation in steels in order to characterize the atomic environments near twin, lath and αmartensite boundaries. This paper describes current progress in this program.

Figures A and B show lattice image and conventional bright field image of the same area of a duplex Fe/2Si/0.1C steel described elsewhere(4). The microstructure consists of internally twinned martensite (M) embedded in a ferrite matrix (F). Use of the 2-beam tilted illumination technique incorporating a twin reflection produced {110} fringes across the microtwins.
Analysis Of Multipoints On A Particle Using A Computer Controlled Sem
Authors: Hoover M.R. , Lebiedzikf J. , Strickler D.W.
Published: June 2020

The computer controlled SEM has been used extensively to study mineral matter in coals and residues from solvent refined coals (SRC). Both dispersed powders and polished sections have been studied. The dispersions have been made on beryllium substrates using the camphor-napthalene (1) and also frozen distilled water sublimination techniques. The polished sections have been prepared by vacuum impregnating the samples with a thermo-setting resin. To achieve some contrast in the electron back-scattered (EBS) signal, a cobalt-rich hardener has been used with the resin. With an inverted EBS signal the coal grains appear brighter than the background.

The automated SEM recognizes a grain of coal or other feature of interest by using the fact that a signal (EBS, SEI, etc.) from the feature is brighter than the same signal from the background material. The SEM determines the average diameter of the particle by summing the lengths of eight diameters taken every 22.5° and dividing by eight.
Electron Microscopic Observations on Virus-Like Particles of a Catfish Papilloma
Authors: Edwards M. R. , Samsonoff W. A.
Published: June 2020

Papillomas in catfishes have been described (1) but the presence of viruses in these tumors has not (2). This report is concerned with the study of a papilloma found on the lower lip of a brown bullhead (letalurus nebulosus) which had been frozen prior to arrival at our laboratory.

Tumor tissues were thawed in 2.5% glutaraldehyde and postfixed in 1$ osmium tetroxide. Both fixatives were prepared in Millonig's buffer. Fixation, washing, dehydration, and Epon embedding were accomplished according to conventional electron microscopic techniques.

Examination of thin sections revealed virus-like particles in epidermal cells which constituted the major part of the neoplasm (Fig. 1). No particles were found in the connective tissue surrounding the epidermal papillae. The cells containing particles were usually isolated from one another, had a spindle or fusiform shape, and exhibited many cytoplasmic extensions in random directions. Their nuclei were pleomorphic and displayed irregular nuclear envelopes with relatively large lacunae. Vesiculation of the cytoplasm was extensive, apparently caused by dilations of the endoplasmic reticulum.
Systematic Morphological Variability along the Length of Muscle Fibers in Extraocular Muscle of Rabbit: A Study in Serial Sections
Authors: Davidowitz Jacob , Pachter Bruce R. , Philips Gloria , Breinin Goodwin M.
Published: June 2020

A basic assumption underlying the discrimination of different structural fiber types in extraocular muscle (EOM) has been that of morphological constancy along the length of individual fibers. In the present study, marked variation of a consistent nature was observed along both singly innervated fibers (SIF) and multiply innervated fibers (MIF) in the orbital surface layer of rabbit superior rectus. The muscle of prepubertal (2 Kg) New Zealand white rabbit was embedded whole in Epon and serially sectioned at 5u, thus permitting the following of respective fibers and their ultrastructural sampling from end to end (1). The presence of two varieties of MIF in addition to the SIF of this layer has been describe by light microscopy (2), as has the occurrence of endplatelike neuromuscular junctions on these MIF in addition to their numerous small junctions (3).
Comparison of Acrylamide and Agar Gels by Freeze-Etching
Authors: Steere Russell L. , Erbe Eric F.
Published: June 2020

Thin sheets of acrylamide and agar gels of different concentrations were prepared and washed in distilled water, cut into pieces of appropriate size to fit into complementary freeze-etch specimen holders (1) and rapidly frozen. Freeze-etching was accomplished in a modified Denton DFE-2 freeze-etch unit on a DV-503 vacuum evaporator.* All samples were etched for 10 min. at -98°C then re-cooled to -150°C for deposition of Pt-C shadow- and C replica-films. Acrylamide gels were dissolved in Chlorox (5.251 sodium hypochlorite) containing 101 sodium hydroxide, whereas agar gels dissolved rapidly in the commonly used chromic acid cleaning solutions. Replicas were picked up on grids with thin Foimvar support films and stereo electron micrographs were obtained with a JEM-100 B electron microscope equipped with a 60° goniometer stage.

Characteristic differences between gels of different concentrations (Figs. 1 and 2) were sufficiently pronounced to convince us that the structures observed are real and not the result of freezing artifacts.