bluuebunny/crossref_metadata_2025_split huggingface dataset:
Use of an Energy Dispersive X-ray Spectrometer on a Transmission Electron Microscope
Authors: Geiss Roy H. , Jesser William A. 
Published: June 2020

An Ortec Si(Li) energy dispersive X-ray detector designed for use on a Cambridge scanning electron microscope has been coupled to a Siemens transmission electron microscope by replacing the side tilt control on the Siemens by a brass tube as shown in figure 1. The Siemens specimen holder was modified to tilt the specimen approximately 20° from a horizontal position and to elevate it such that it is just visible to the detector through the side port. This increased specimen height requires an objective focal length of greater than 8 mm and consequently effects a lower resolution of the image, especially at low accelerating voltages. The peak/background in the X-ray spectra is best at 40kV, however, and deteriorates progressively with increasing accelerating voltage.Experiments similar to those of Fuchs, who employed a wavelength dispersive system on a Siemens TEM to measure film thickness, were repeated with the present energy dispersive system by analysing spectra from vacuum deposited gold films of various thicknesses. A linear relation between peak height and thickness was confirmed for several films up to 2000Å thick by comparing spectra from two adjacent grid squares, one covered by a single thickness of gold, the other covered by a double thickness, and noting that the peak heights were in the ratio of 1:2 to within a few percent.
New Three-Dimensional Algebraic Reconstruction Techniques (Art)
Authors: Gordon Richard , Bender Robert 
Published: June 2020

Algebraic reconstruction techniques (ART) for 3-dimensional reconstruction from electron microscope data have been developed and implemented in this laboratory. These methods are an alternitive to the Fourier method of de Rosier and Klug and have several advantages over it, such as:relatively few views are required (about 6-12)limited angular ranges give useful reconstructions (+/-30°)no presumption of symmetry is necessary for facile implementingcomputation is fasterthe computation is stable in the presence of noiseThe dimensionality of the problem may be reduced from three to two by tilts about a single axis, so that planes perpendicular to the axis of tilt are independent of each other. This is not absolutely necessary, but is by far the most tractable mode computationally. A typical input data set, then, consists of m≥6 photos of the same region of the specimen at several known angles of tilt about the same axis. In general the direction of the tilt axis is not known.
Preparation of Transmission Electron Microscopy Samples from Silicon Integrated Circuits
Authors: Smith P. J. , Kulkarni M. V. , Troutman H. A. 
Published: June 2020

A new preparation technique for transmission electron microscopy samples has been developed which allows an individual device within a silicon integrated circuit to be thinned.Typical devices within present silicon integrated circuits are located in the top few microns of a silicon chip, Fig. 1, and have lateral dimensions on the order of a fraction of a millimeter. Sample preparation for electron microscopy is usually accomplished by jet-etching the bottom side of the wafer, directly under the device of interest; thickness is estimated by the color of transmitted light. It is extremely difficult to ensure that the sample will be thinned in exactly the area of interest since the jet is incident on the bottom side of the sample while the device is on the top side, making exact alignment difficult; the jet is large compared to transistor dimensions; the presence of differently doped regions leads to non-uniform thinning.
The Interpretation of Crystal Lattice Images
Authors: Cowley J. M. , Iijima Sumio 
Published: June 2020

With the high-resolution electron microscopes now commercially available, it is possible to obtain resolution in images of crystal lattices of 2Å or better. While this is applied most frequently for obtaining simple fringe patterns from materials having small unit cells, it may also be used to resolve detail within the unit cell of more complicated structures as in figure 1, obtained with a JEM-100B electron microscope at 100kV. We are investigating means for obtaining better images, e.g. by the use of pointed filaments, and are studying the possibility that the details of contrast in such images may be interpreted in terms of the crystal structure.Since a thin crystal is primarily a phase object, a simple, intuitive interpretation of the contrast is not possible. Calculations of contrast made by Elizabeth Chidzey (1970) using a phase-grating approximation for very thin crystals and a more complete n-beam dynamical theory for thicker crystals have confirmed the strong dependence of the contrast on crystal orientation, crystal thickness and the defocus of the microscope.
Observations on the Structure of Ultramicrotomed Thornel—50 Carbon Fiber
Authors: Phillips V. A. , Hugo J. A. , Roberts B. W. 
Published: June 2020

Previous lattice plane observation on high strength carbon filaments has shown a high degree of alignment of the (00.2) basal planes parallel to the filament axis. Most of these observations have been made on thin electron-transparent protrusions from fractures, on fibers ground and dispersed ultrasonically, or through the periphery of corrugated filaments. In all cases the axis of the filament was parallel to the plane of the micrographs. However, in order to arrive at an appropriate 3-dimensional model of the structure, it is necessary to know the arrangement of the packets of planes in the third dimension. The results of Harling, indicated that ultramicrotomy could be used.Thornel—50 Union Carbide Co. C-fiber, which is made from alpha cellulose (rayon) precursor, was mounted in Araldite for sectioning. Slices cut with a diamond knife were examined in a Philips EM300 microscope at 100 kv.
Determination of Preferred Orientation in Crystals from Surface Diffraction Techniques
Authors: Diggs Isaac W. 
Published: June 2020

This paper will examine a method of determining preferred orientation in reflection diffraction specimen without the use of a camera constant for the electron microscope. This method was devised in the absence of being able to find any such method in the literature. The method was used to study the orientation of nickel crystals grown on the faces of Al2O3 substrates. The diffraction work was done with 75kv (.0446A) electrons on a model HU-11 Hitachi Electron Microscope. Diffraction patterns were recorded on a photographic film in such a manner that successive frames showed pattern change as a function of angular displacement (tilt rotation).If for any surface diffraction pattern, the orientation data of the crystals involved were desired, the following procedure would yield accurate results. The first action is to reproduce the pattern at a convenient size. This can be done by photographic means or by any other means available. Next, the interplanor spacings should be measured for at least three sets of planes which appear in the pattern.
Interaction of Gallium with Copper Surfaces
Authors: Chen Y. T. , Lawless K. R. 
Published: June 2020

The interaction of gallium with single crystalline copper surfaces has been investigated by means of high energy glancing angle electron diffraction, transmission microscopy and metallography. Surface structural changes and morphological changes were both recorded. Gallium was deposited in-situ onto both bulk single crystalline copper surfaces and thin film Cu surfaces grown in-situ on (100) NaCl surface inside the HEED apparatus.Cu-Ga alloy films were observed to grow epitaxially at room temperature on clean (111), (001) and (110) copper surfaces. The epitaxial growth was obgerved only with a deposition rate for Ga of approximately 30 A/min. and on clean copper surfaces. No epitaxial growth of Cu-Ga alloy films was observed on surfaces covered with cuprous oxide. Higher deposition rates always gave diffuse ring type patterns. An early stage ordered ʓ h.c.p. phase was observed to grow on Cu (111) face. A later stage Ø tetragonal phase was observed to grow on all three faces of Cu with three orientations on the (111) face, four major orientations on the (001) face and two orientations on the (110) face.
Precipitation Within a Precipitate—Nickel-Rich Alloys of Nickel, Aluminum and Titanium
Authors: Oblak J. M. , Kear B. H. , Leverant G. R. 
Published: June 2020

Figure 1 shows how a precipitate of γ might form within a precipitate of γ' in a given Ni-Al-Ti alloy. The alloy reverts to single phase fcc γ on heating above the solvus temperature TS. Upon aging at T1 an LI2 γ' Ni3 (Al,Ti) phase of composition is formed and is in equilibrium with a γ matrix of composition. . If the alloy is subsequently aged at a lower temperature T2, not only does additional γ' form within the matrix, but γ can also precipitate within γ', provided that the γ' phase boundary is as represented.In this study a Ni-10.7Al-5.1Ti (at. %) alloy was air cooled from a solution temperature of 2250°F to form coarse γ' particles. The cooling rate was sufficiently rapid that equilibrium was not. achieved at temperatures corresponding to T2 in Figure 1. Samples were then aged for 16 hours at l400°F and their microstructure examined. As evident in Figure 2(a,b), the large γ' particles contained small plate-like precipitates after aging and these appeared to lie on {100} planes.
Microscopical Characterization of Grafted Cotton Fibers
Authors: Goynes Wilton R. 
Published: June 2020

Radiation induced graft polymerization of the cellulose of cotton fibers with various other polymers produces textile fibers with new properties. Chemical analysis and physical tests are used to determine changes in such properties as breaking strength, wrinkle recovery angle, and resistance to abrasion. While such tests give reliable evaluations of the overall nature of any improvement, they give little information on what changes actually occurred in the fiber itself. One means of obtaining this information is through microscopical observations.Penetration and reaction of the polymer within yarns and fibers can be tested by cutting Hardy cross sections of the fibers after they have been dyed with a stain specific for the reacted polymer. More detailed information can be obtained from ultrathin sections, using the transmission electron microscope. Structural changes often occur which are obvious from comparison of cross sections of untreated and treated fibers. Use of the scanning electron microscope permits evaluation of changes in surface features of fabrics and individual fibers.
Scanning Electron Microscopy of the Choroid Plexus and Ventricular Wall Ependyma in the Rhesus Monkey
Authors: McGrath Philip P. , Clark Ronald G. , Ewell John B. , Wehrung John M. 
Published: June 2020

The lumen of the lateral ventricles is separated from the brain parenchyma and the circulatory system by a single layer of specialized epithelial cells, the ependyma. This ependyma is divided into choroid plexus ependymal cells, which coat the pia arachnoid invagination in the lateral ventricles, and the wall ependymal cells which separate the lateral ventricle lumen from brain parenchyma. Using transmission electron microscopy, the ultrastructure of these cells has been described with special emphasis on the difference in apical surface membranes. The apical surface of the choroid plexus ependymal cell contains numerous microvilli and an occasional cilia while the wall ependymal cell contains numerous cilia and only a few microvilli. By scanning electron microscope we have demonstrated differences in the apical surface membrane.The specimens were fixed in glutaraldehyde by vascular perfusion or infusion into the ventricles and postfixed in osmium tetroxide. They were rinsed in cacodylate buffer and three changes of distilled water, blotted dry, and freeze dried, using liquid nitrogen. They were coated with gold palladium and examined in a Cambridge Mark II A stereoscan, scanning electron microscope.
Differentiation of Ribosomes and Beta Glycogen in Canine Myocardium
Authors: Bishop Sanford P. 
Published: June 2020

During the ultrastructural examination of the canine myocardium, it became apparent that the positive identification of specific granules as either ribosomes or β glycogen was very difficult in sections stained with lead citrate and uranyl acetate. In the normal adult canine myocardium ribosomes are not a prominent organelle, but in certain conditions, free ribosomes may become greatly increased in number. Unlike some other species, glycogen and ribosomes are very nearly the same size (200-250 Å) in the canine myocardium. Following glutaraldehyde fixation and epoxy resin embedding there is considerable variation in electron density of glycoen (Fig. 1).In an attempt to differentiate glycogen from free ribosome particles, myocardial samples from four normal dogs and six dogs with experimental right ventricular hypertrophy were processed 1) according to routine procedure, 2) following autolysis, 3) following diastase digestion and 4) by the periodic acid silver proteinate method of Theiry (J. Microscopie 6:986, 1967).
Electron Microscopy of the Hypertrophic Scar
Authors: Kischer C. W. , Linares H. , Dobrkowsky M. , Larson D. L. 
Published: June 2020

Hypertrophic scarring frequently occurs during or after the healing of deep second degree or third degree burns or equivalent trauma to the body surface. Clinically, the scar begins as a generalized firming or hardening of the skin area with an increased reddening over that of normal skin. These conditions intensify rapidly. The scar elevates and begins contracting, sometimes resulting in serious deformities, grotesque appearance, and severe loss of function.During development of the scar the reticular dermis undergoes an unusual reconstruction. The collagen fibers first become oriented into whorl-like arrangements, which most likely develop further into discrete nodules. The etiology of the hypertrophic scar is unknown. However, since nodular formation is so characteristic for the scar an examination of the nodule itself may suggest etiologic possibilities for the scar.
Pathology of Bone Cells in Pigs with Experimental Turbinate Osteoporosis (Atrophic Rhinitis)
Authors: Fetter A. W. , Capen C. C. 
Published: June 2020

Atrophic rhinitis in swine is a disease of uncertain etiology in which infectious agents, hereditary predisposition, and metabolic disturbances have been reported to be of primary etiologic importance. It shares many similarities, both clinically and pathologically, with ozena in man. The disease is characterized by deformity and reduction in volume of the nasal turbinates. The fundamental cause for the localized lesion of bone in the nasal turbinates has not been established. Reduced osteogenesis, increased resorption related to inflammation of the nasal mucous membrane, and excessive resorption due to osteocytic osteolysis stimulated by hyperparathyroidism have been suggested as possible pathogenetic mechanisms.The objectives of this investigation were to evaluate ultrastructurally bone cells in the nasal turbinates of pigs with experimentally induced atrophic rhinitis, and to compare these findings to those in control pigs of the same age and pigs with the naturally occurring disease, in order to define the fundamental lesion responsible for the progressive reduction in volume of the osseous core.
Permeability in the Blood-Brain Barrier in Monkeys Following Exposure to High Altitude
Authors: Demaree R.S. , Ackerman L.J. , Anderson D. L. 
Published: June 2020

People who rapidly ascend to high terrestrial elevations may experience the “acute mountain sickness” syndrome. Speculation and limited evidence suggest that cerebral edema may play an important role in initiating and perpetuating this condition. We have recently demonstrated by electron microscopy that a mild cerebral edema develops in some Cebus apella monkeys rapidly transported to 14,110 feet. In the present study, Cebus apella monkeys were terminated at 1, 3, or 5 days after being shipped from sea level (160 feet) to 14,110 feet without acclimatization at intermediate altitudes.Thorotrast was administered IV 30 minutes prior to termination by perfusion or guillotine. Cerebral cortex was fixed by either perfusion or immersion in glutaraldehyde, and postfixed in osmium tetroxide. Following fixation, the tissues were dehydrated in ascending concentrations of ethanol followed by propylene oxide and embedded in Epon 812. Ultrathin sections were either not stained or doubly stained with uranyl acetate and lead citrate.
Continuous Type C Virus Production in a Tissue Culture of Human Origin (Burkitt Lymphoma)
Authors: Priori Elizabeth S. , Dmochowski Leon , Myers Brooks , Wilbur Jordan R. 
Published: June 2020

Electron microscopy of numerous tissue cultures derived from various types of human tumors revealed only occasional type C virus particles in tissue cultures of leukemia and lymphoma (Dmochowski, L., Fourteenth Annual Conf. on Cancer, Yearbook Medical Publ, Inc., 37, 1969) and of solid tumors such as osteosarcoma, giant cell tumors (Priori, E. S. et al., J. Nat. Cancer Inst., 1971, in press), and in rhabdomyosarcoma.This report describes a monolayer tissue culture derived from pleural effusion cells of a patient with Burkitt lymphoma (American type) which continuously produces type C virus particles. The child expired 14 days after collection of the pleural effusion due to a generalized varicella infection. Varicella virus particles could not be found in the original pleural effusion cells nor in any of the tissue culture passages.
Lysosome-Like Bodies in the Hepatopancreas of Oniscus Ascellus
Authors: Roberts John W. , Witkus E. R. 
Published: June 2020

The hepatopancreas of the Isopod, Oniscus ascellus is comprised of two pairs of blind-ending diverticula which empty into the straight-line digestive tract through the hepatopancreatic duct. The cells at the blind distal tip are unspecialized regenerative cells. Mitotic activity of the cells in this region pushes older cells proximally in the lobe. As this occurs, the cells differentiate into either secretory B-cells or absorptive S-cells. By making serial sections, it is possible to trace the differentiation of the regenerative cells into both cell types.Lysosome-like bodies were observed within the secretory B-cells. These bodies were found to measure approximately 0.5 to 2.5 microns in diameter. These bodies also were observed to contain many membrane-figures (fig. 1).
Complex Carbohydrates Associated with the Tegument and Subtegument of the Developmental Stages of the Blood Fluke, Schistosoma Mansoni
Authors: Shannon W. Allen 
Published: June 2020

Periodic acid-thiocarbohydrazide-osmium(PATCO) and periodic acid-chromic acid-silver methenamine (PACrAS) techniques are employed to visualize complex carbohydrates. The nature of the various inclusions observed in the tegument and subtegument and the acetabular gland inclusions is of particular interest.In the sporocyst stage, glycogen (gl) is the most prominent PATCO-(Fig.1) and PACrAS-positive substance in the tegument or subtegument. The Ig type of inclusion gives a positive PATCO (Fig.1) or PACrAS reaction when found in the tegument but not when associated with glycogen deposits in the subtegument. In immature cercariae, the glycocalyx (g) as well as the postacetabular gland inclusions (PO) react strongly to the PATCO (Fig.2) and the PACrAS techniques. Both reactions result in some variation in intensity in the postacetabular gland inclusions which may reflect the state of formation or condensation of the ingredients. The preacetabular gland inclusions (PR) are not reactive and disintegrate somewhat under the conditions of the experiments (Fig.2). I1 and I2 types of inclusions in the tegument react intensely (Fig.2). In addition, I3 inclusions in the subtegument exhibit what appears to be a positive reaction with the PACrAS technique.
Optical Shadowing of Macromolecules
Authors: Haydon Glen B. , Hill Bruce C. , Lemons Ross A. 
Published: June 2020

Dramatic 3-D effects resembling that seen in the scanning microscope are possible with the conventional transmission electron microscope employing its full resolution. The effect is especially useful in the study of macromolecules spread upon a substrate. Three examples illustrate the potential:(1) A strand across a hole in a clean parlodion-carbon film, Figure 1,(2) A typical shadowed preparation of DNA, Figure 2,(3) A preparation of ferritin, Figure 3Although it is premature to draw definitive interpretations from such micrographs, some speculation is possible. Since the optically shadowed image of fresh carbon films shows a very smpoth surface as seen in Figure 1, the rough appearance seen in Figures 2 and 3 must be related to the material which is placed upon the substrate. A part of the appearance probably results from aggregated protein material distributed over the surface. The alteration of such protein structures by the electron beam is not understood. Sufficient exposure to image a molecule might be expected to cause significant molecular rearrangement or dissociation (Breedlove & Trammell, Science 170:1310, 1970). Thus, the rough appearance is that of the organic residue altered to a more stable form in the beam. In the ferritin preparation, Figure 3, the iron cores appear upon a rough surface which is presumably composed of denatured proteins further modified by the electron beam.
High Resolution Stereography of Complementary Freeze-Fracture Replicas Reveals the Presence of Depressions Opposite Membrane Associated Particles of Split Membranes
Authors: Steere Russell L. 
Published: June 2020

Complementary replicas have revealed the fact that the two common faces observed in electron micrographs of freeze-fracture and freeze-etch specimens are complementary to each other and are thus the new faces of a split membrane rather than the original inner and outer surfaces (1, 2 and personal observations). The big question raised by published electron micrographs is why do we not see depressions in the complementary face opposite membrane-associated particles? Reports have appeared indicating that some depressions do appear but complementarity on such a fine scale has yet to be shown.Dog cardiac muscle was perfused with glutaraldehyde, washed in distilled water, then transferred to 30% glycerol (material furnished by Dr. Joaquim Sommer, Duke Univ., and VA Hospital, Durham, N.C.). Small strips were freeze-fractured in a Denton Vacuum DFE-2 Freeze-Etch Unit with complementary replica tooling. Replicas were cleaned in chromic acid cleaning solution, then washed in 4 changes of distilled water and mounted on opposite sides of the center wire of a Formvar-coated grid.
Biological Applications of the Scanning Transmitted Electron Microscope
Authors: Matsuo Tatsuya , Suzuki Mikio 
Published: June 2020

Recently, very thick section of biological specimens have been observed by using super high voltage electron microscope to obtain a three dimensional model of a specimen.However, the thicker the section, the more difficult the penetration of staining solution into the depth of thick section. So, it is doutful whether the stain solution fully penetrated into the thick section. This paper reports an observation of various thick unstained sections using scanning transmitted electron microscope(STEM) and conventional electron microscope(CEM).The observed specimen is mice liver cells. The tissue was fixed in cold 1% phosphate-buffered osmium tetroxide solution for 2 hours. After fixation, the tissue was dehydrated in a graded series of ethanols and then embedded in Epon 812. The 500 Å, 5,000 Å and 1μ thick sections were cut, not stained with uranyle and lead, and then examined with STEM and GEM operated at accelerating voltage 80 kV.