bluuebunny/crossref_metadata_2025_split huggingface dataset:
Oxygen precipitation in carbon-containing silicon
Authors: Tsai H.L. , Carpenter R.W. , Peng J.D. 
Published: June 2020

The effect of carbon on oxygen precipitation in heat-treated silicon has been of current research interest. It has been suggested that carbon impurity may act as nucleation center for oxide precipitates (1). On the other hand, evidence indicates that the precipitate density does not necessarily increase with the carbon concentration (2). In this paper, we report the results of the TEM study of oxide precipitates in the carboncontaining CZ silicon under various heat-treatment conditions.The (111) wafers which were cut from several positions along a silicon ingot were initially annealed at 750°C for various times ranging from 0 to 100 h and were second-step annealed at 1050° C for 16 h or 11 h. Some (100) wafers were preannealed at 750°C for 100 h and then annealed at 1050°C for 0 to 8 h. Initial oxygen concentrations in the as-grown silicon crystals were in the range of (1.4-1.7) x 1018 cm-3 and carbon concentrations were (2-9) x 1016 cm-3.
Examination of optical fibers by the luminescent method in the scanning electron microscope (SEM)
Authors: Wells Oliver C. , Bailey Philip J. 
Published: June 2020

Light is transmitted along the central core of an optical fiber by total internal reflection at the interface with the surrounding layer. Here, we describe a method by which the optical properties of a cross-sectioned fibre can be studied by means of the luminescent image in the scanning electron microscope (SEM).The sample is prepared by depositing a thin cathodoluminescent layer over the end of a broken or cross-sectioned optical fiber. A thin conducting layer is then deposited to prevent charging. The far end of the fiber is optically coupled to a photomultiplier. During examination in the SEM, the sample is scanned by a fine electron beam, which gives a localised source of light on the surface of the sample at the point of impact of the beam. The quantity of light that is transmitted along the fiber to the photomultiplier determines the brightness of that particular pixel in the recorded image.
Quantitative measurement of magnetization distribution in domain walls of 1.2%Fe-Co by differential-phase-contrast STEM
Authors: Tsuno K. , Sekiguchi T. , Watanabe D. , Kersker M. 
Published: June 2020

When a ferromagnetic specimen is observed under diffraction mode of an electron microscope, central spot splits according to the magnetization direction in the magnetic domain of the specimen. Amount of shift of the diffraction spot is proportional to the intrinsic magnetization and specimen thickness. Magnetic domain can be seen under the image mode by covering one of the spots with an objective aperture.If electron intensity of split diffraction discs are detected by the two adjacent detectors, one signal is subtracted from the other and the subtracted signal is displayed under the scanning mode, domain image can also be displayed under the STEM mode. This magnetic domain observation technique (differential phase contrast (DPC) STEM) has been investigated by Chapman et al.
TEM observations on pores in alumina
Authors: Morrissey K. J. 
Published: June 2020

Pores play an important part in the microstructural development of ceramic materials such as α-Al2O3. In sintered materials pores are often found at two grain interfaces, grain boundary triple points, and in integranular regions. The separation of pores from grain boundaries in the final stage of sintering results in the isolation of the pores and prevents the material from reaching full density. The process of pore-breakway is an important aspect of the study of grain boundary migration.This investigation has centered on observing pores in as received polycrystalline α-Al2O3 compacts and thin films of α-Al2O3. This report is part of a larger study on grain boundaries and interfaces in Al2O3. The first observations of pores in this study were made on an α-Al2O3 sample which had been extruded and sintered, MgO was used as the densification aid. Pores can affect the migration of a boundary by pinning it, moving with the boundary, or the boundary may move past the pore.
Lattice misfit by convergent-beam electron diffraction - Part II: Energy measurement
Authors: Lin L. S. , Walsh J. M. 
Published: June 2020

Geometry measurement described in Part I required photographing the CBED and measuring the height of the triangle Pγ, Pγ' and the folz ring radius Rγ/γ'. These manipulations can be eliminated by an energy measurement approach first described by Steeds. Using the small angle approximation to Bragg's law givesFor a cubic material with lattice constant a, Eq. (1) can be restated asSmall changes in the accelerating voltage will change the position of holz lines and are related to changes in lattice constant as in Eq. (4)
Translation symmetries in convergent-beam electron diffraction
Authors: Buxton B. F. , Shannon M. D. , Eades J. A. 
Published: June 2020

For crystallographic studies in the transmission electron microscope the “ideal” sample is considered to be a parallel sided slab, oriented perpendicular to the electron beam, cut from perfect crystal. Such a slab does not, in general, have the full symmetry of the crystal from which it has been cut. As a result, there arises the question as to whether the symmetry observed in the diffraction pattern reflects the symmetry of the slab or that of the infinite, perfect crystal. For the most part this matter is clear but there is one class of situation that has been (and perhaps still is) the subject of some debate.If the infinite crystal contains glide planes or screw axes for which the corresponding translation is not parallel to the slab, then, strictly speaking, the slab does not have these symmetries. Normally, however, in transmission electron diffraction patterns, symmetry features that result from the presence of these symmetry elements are observed (although Goodman asserts that they should not be).
A complex network of “snake-like tubules” revealed by the NADPase cytochemical reaction in the acinar cell of pancreas
Authors: Beaudoin A.R. , Grondin G. , Lord A. , Pelletier M. 
Published: June 2020

We have recently described the ultrastructural localization of NADPase activity in the exocrine pancreas of rat. The enzyme was found in the intermediate saccules of the Golgi apparatus, in dense bodies and lysosomes but was absent from zymogen granules. A very intense reaction was noticed in a peculiar structure which was termed “Snake-Like Tubule” (SLT). The purposes of the present study were firstly to delineate SLT distribution in the acinar cell and secondly to define any possible relationship or association with other cellular organelles.NADPase cytochemical reaction was performed on the pancreas of adult Sprague Dawley rats. Small lobules were excised and fixed for 50 min, at 4°C, in 2% glutaraldehyde buffered with 0.1M cacodylate at pH 7.2. Lobules were rinsed several times with the same buffer containing 570 sucrose and cut with a Mcllwayn tissue chopper. Sections were washed several times with buffer and incubated for 2 hr at 37°C in the following medium: 4mM NADPH; 40mM sodium acetate buffer, pH 5.0; 4mM lead acetate and 5% sucrose.
An ultrastructural investigation of urethane-induced lung tumors in strain-A mice
Authors: Gunning W.T. , Stoner G.D. , Maklinson A.M. , Goldblatt P.J. 
Published: June 2020

The cellular origin of chemically-induced lung tumors in mice has not been completely resolved. Brooks (1968) reported that most urethane-induced lung tumors in strain A mice were derived from type II alveolar epithelial cells. In contrast, Kauffman (1981) observed that the majority of clinically- induced lung tumor in Swiss mice were derived from Clara cells of the bronchiolar epithelium. Preliminary results from the present study are in agreement with those of Kauffman (1981) in that most urethane-induced lung tumors in strain A/J mice appear to be derived from Clara cells.Eight week-old female A/J mice were injected I.P. with 1000 mg/kg of urethane. Twelve months after injection, the mice were sacrificed by cervical dislocation and their lungs fixed in buffered 4% formalin - 1% glutaraldehyde, introduced via the trachea. Tumors in the right lung were identified grossly, catagorized according to size (<1-.5, 1.6-5, and >5 mm in diameter) and location (centrolobular or peripheral), and prepared for both light and electron microscopy.
Light and ultrastructural studies of renin granules in methacrylate and epon embedded kidneys
Authors: Tausch J.H. , Moore J.D. , Barsoum N.J. , Gough A.W. , Sturgess J.M. 
Published: June 2020

The juxtaglomerular apparatus (JGA) is a distinct morphofunctional unit in the kidney and the main constituent cells are modified smooth muscle cells called juxtaglomerular (JG) cells. JG cells, located within the sleeve of afferent arterioles of glomeruli, are characterized morphologically by secretory granules. The granules contain renin, an enzyme of the reninangiotensin-aldosterone system that regulates blood pressure and electrolyte balance. The purpose of this report is to describe plastic embedding and staining procedures used to study renin granules by light and electron microscopy in a rat experimental model.The rats were orally administered enzyme inhibitors that induced hypertrophy and hyperplasia of JG cells resulting in increased storage and synthesis of renin granules. At necropsy, thin transectional slices of renal cortex were collected and specimens for light and ultrastructural examination were taken from adjacent cortical tissue in each rat. For histology, 2 mm thick slices of kidney were fixed in neutral buffered formalin.
Morphometric analysis of the effects of phosphorus and chromium on a diatom
Authors: Lazinsky Diane , Sicko-Goad Linda 
Published: June 2020

Nutrients, particularly phosphorus, may influence, and in some cases, mediate toxicity effects of heavy metals on algae. Further, heavy metal and phosphorus uptake can be coupled and the metal may be incorporated into polyphosphate bodies thereby reducing the amount of metal available to intracellular sites. A series of experiments was designed to evaluate the effects of chromium on a diatom and to determine if these effects are modified by the phosphorus status of the cell.A cultured diatom, Cyclotella aff. meneghiniana was the test organism and was grown in WC medium at 20°C. The experimental regime consisted of control cells with the following phosphorus status: phosphorus deficient, phosphorus sufficient, and an overplus of phosphorus which was achieved by placing cells in phosphate free medium and then adding double the standard amount of phosphorus. Hexavalent chromium at a concentration of 0.2 μg-at/L was added to each of the above phosphorus categories. The addition of chromium to the overplus cells occurred before overplus and following the period of overplus.
Electron Microscope Study of the Effect of Substrate Metal Dislocation Structure on the Structure of Electrodeposited Nickel
Authors: Gundiler I. , Murr L.E. 
Published: June 2020

The role of dislocations on crystal growth was first introduced by Frank and an extensive treatment of the theory was developed by Burton, et al. The growth parameters pertaining to electro-crystallization have been defined, and theories on the mechanism and kinetics of electrodeposition have been developed. The formation of spirals and pyramidal growth patterns are both explained by the screw-dislocation mechanism. Two dimensional nucleation on displacement-free surfaces and step-bunching mechanisms have also been suggested.Although a surface-diffusion-to-dislocation-steps mechanism for electrocrystallization is generally accepted, the effect of dislocation structure and density in the substrate on the microstructure of electrodeposited metals has not been systematically studied.
Clustering and Fluctuation Characteristics of Carbon Films Observed in Darkfield Electron Microscopy
Authors: Brakenhoff G. J. 
Published: June 2020

It is possible to determine in darkfield EM the relative mass of, for instance, biological particles. The method is based on the linear relationships, first in darkfield EM between mass and the electron intensity scattered by it, and second between electron intensity and the photographic density in the micrograph. Limitations are set by the background structure present in thin carbon supporting films. Although films without structure (i.e. graphite lamellae, 2)) could be used, this seems not practicable for day to day biological application, hence this investigation of the more common carbon films.The darkfield mass determination method was modified to obtain particle mass distributions by computer. The micrographs are scanned by a densitometer on a network of (in this case) 50x50μm measuring grid and the density values are put on magnetic tape.
Characteristics and Application of Temperature-Field Emitters
Authors: Tamura N. , Goto T. , Harada Y. 
Published: June 2020

On account of its high brightness, the field emission electron source has the advantage that it provides the conventional electron microscope with highly coherent illuminating system and that it directly improves the, resolving power of the scanning electron microscope. The present authors have reported some results obtained with a 100 kV field emission electron microscope.It has been proven, furthermore, that the tungsten emitter as a temperature field emission source can be utilized with a sufficient stability under a modest vacuum of 10-8 ~ 10-9 Torr. The present paper is concerned with an extension of our study on the characteristics of the temperature field emitters.
Dynamical Scattering in Crystalline Biological Specimens. II. The Domain of Validity for Different Approximations
Authors: Jap Bing K. , Glaeser Robert M. 
Published: June 2020

Unlike other complex dynamical scattering approximations, the phase object approximation and the higher order phase object approximation give an invertible relationship between the projected object potential and the transmitted wave function. These two approximations therefore offer an attractive solution for correcting the dynamical scattering effects in electron micrographs. There is, however, only a limited domain in terms of resolution, specimen thickness and electron energy in which the approximations are valid. We have evaluated the domain of validity for each approximation, using the criteria discussed in part I.The multislice formulation of Cowley and Moodie was used as our point of reference to calculate the 'exact' diffracted wave function of organic crystals. Anhydrous Cytosine crystal and 'DISOPS' (Disodium 4-Oxypyrimidine-2-sulfinate Hexahydrate) were used as our test objects.
A New Method for Single Atom Specimen Preparation
Authors: Chiu W. , Glaeser R. M. , Prussin S. 
Published: June 2020

A reliable method of confirming that one is able to produce single atom images in high resolution electron microscopy is to make a comparison of the number of atoms per unit area that is seen by the electron microscopic observations and the number per unit area as determined by a separate experimental technique of high accuracy. This report presents a method of preparinga specimen composed of a low distribution of gold atoms (ca. 1 atom/104 Å2) sandwiched between two ultra-thin carbon films, and also a method of measuring the gold atom density in the specimen by neutron activation analysis.The specimen was prepared by evaporation onto a freshly cleaved mica substrate in a vacuum evaporator, as shown in Figure 1. One side of the vacuum chamber was used to prepare a thin carbon film according to the method of Williams and Glaeser (1972), and the other side was used to evaporate the gold atoms from a molybdenum strip, which had a micro-quantity of gold deposited on a 1 cm2 surface area from a previous evaporation.
Lattice Images at θ’ Precipitates in Al-3%Cu Alloy
Authors: Phillips V. A. 
Published: June 2020

As part of a high resolution electron microscopic study of the precipitation sequence at 130°C in aluminum - 3% copper alloy, we studied G. P. [1], G. P. [2] or θ”, and θ’ precipitates by the lattice imaging technique. This approach proved valuable for phase identification and distinction. Examples of cros sed-lattice and c-plane lattice images at θ’ platelets will be presented here.Slices were spark cut nearly parallel to {001} from a melt-grown single crystal of aluminum -3.0 wt. % copper, previously solution treated at540°C and water quenched. Slices were aged at 130°C in argon and hand ground. Discs were chemically, electrolytically or in one case ion thinned, and examined at 100 kV in a slightly modified Philips EM 300 microscope.In the aluminum-copper system, the intermediate phases (G. P. zones and θ’) separate parallel to cube matrix planes, so that the slice orientation chosen resulted in two sets of platelets being parallel and one set normal to the beam.
Stereoscopic Methods in TEM
Authors: Thomas L. E. 
Published: June 2020

The use of stereoscopy to characterize three-dimensional structures observed by TEM has become widespread since the introduction of instruments operating at 1 MV. In its emphasis on whole structures and thick specimens this approach differs significantly from conventional methods of microstructural analysis based on three-dimensional image reconstruction from a number of thin-section views. The great advantage of stereo derives from the ability to directly perceive and measure structures in three-dimensions by capitalizing on the unsurpassed human ability for stereoscopic matching of corresponding details on picture pairs showing the same features from different viewpoints. At this time, stereo methods are aimed mainly at structural understanding at the level of dislocations, precipitates and irradiation-induced point-defect clusters in crystal and on the cellular level of biological specimens. 3-d reconstruction methods have concentrated on the molecular level where image resolution requirements dictate the use of very thin specimens.For the most part the stereo methods used in TEM are direct and unsophisticated. Stereo pairs of micrographs are taken by tilting the specimen to record two views of the same structural features from viewpoints ten or so degrees apart.
Metaphase Chromosomes in the Scanning Proton Microscope
Authors: Escovitz William H. , Fox Timothy R. , Levi-Setti Riccardo 
Published: June 2020

Radiation damage of biological specimens has become a great concern of scientists in high resolution microscopy. Although modern refinements have pushed the ultimate resolution of microscopes below 5Å, specimen damage and preparation techniques have thwarted the realization of this resolution in biological molecules near their natural states. Because Scanning Transmission Ion Microscopy (STIM) with protons is thought to be much more damaging than electron microscopy, critics have doubted the applicability of proton microscopy to biological research, especially at high resolution. As a first step in exploring proton-beam induced damage in biological material, whole-mount chromosomes have been imaged at low resolution by proton microscopy for the first time. After prolonged proton irradiation, the same chromosomes were examined by Conventional Transmission Electron Microscopy (CTEM).Figure 1 is a bright-field proton micrograph of a chromosome obtained from human peripheral lymphocytes. The specimen, prepared by Dr. H. M. Golomb, is unstained and critical-point dried.
Studies of the Crystalline Yolk Complex from Xenopus Laevis
Authors: Collins M.L. , Ohlendorf D.H. , Banaszak L.J. 
Published: June 2020

Yolk platelets isolated from oocytes of Xenopus laevis contain a lipoprotein-phosphoprotein complex arranged in highly ordered microcrystals. The dimeric lipoprotein, lipovitellin, contains about 20% lipid and is complexed with two molecules of a smaller, highly phosphorylated protein, phosvitin. It has been possible to obtain both x-ray data and electron images of the negatively stained lattice. We are trying to use these two approaches to derive a model for the lipovitellin-phosvitin complex. To do this, it has been necessary to: 1) correlate the parameters obtained from x-ray measurements with those from negatively stained lattices, and 2) determine the number of molecules in the unit cell.The x-ray data from wet native crystals indicated an orthorhombic unit cell with dimensions a = 88.5, b = 174.8, and c = 198.9 Å (Ref. 1). Lyophilized native, and wet and lyophilized uranyl acetate stained crystals also produced similar x-ray powder photographs. The cell dimensions of lyophilized uranyl acetate stained crystals were a = 82.6, b = 159.8, and c = 180.4 Å.
Transmission Electron Microscopy of the Brenner Tumor. Contribution to the Histopathogenesis
Authors: accarini I.M. B 
Published: June 2020

The histogenetic interpretation of the Brenner tumor remains obscure, despite the many contributions that attempts to explain their origin.Six human ovaries containing islands of Brenner tumors were studied by histologic procedures and by the electron microscope; special stains, PAS, Oil red 0, toluidin blue and Wilder reticulum were also used. Fresh tissue was fixed in 3% glutaraldehyde, embedded in Epon, stained with Uranyl-acetate, Lead citrate and viewed in RCA E.M. The islands of tumor were located in the cortex, in the stroma or in the deep medulla; they were classified in developing, well developed, and degenerated one, depending upon the comparison of the histologic findings with the ultrastructure of the cytoplasmic organelles. These islands were set in a dense fibrous tissue in the stroma. In one case, the tumor was in the periphery of an ovarian fibroma developed in the ovarian cortex.The ultrastructure of the cells were identical, except for the different degree of degeneration, noted in some cells.
cis—Dichlorodiammineplatinum (II) and its Effect on Microfilaments in Mammalian Cells
Authors: Aggarwal S.K. , McAllister P. 
Published: June 2020

The regression of various tumors after cis-dichlorodiammineplatinum (II) (cis-Pt (II) treatment has been suggested to be mediated through mitotic inhibition and enhancement of the immune system. Present study illustrates the possible action of cis-Pt (II) on microfilaments and their role in the prevention of cytokinesis.Sarcoma-180 ascites cells in culture were treated with cis-Pt(II) (5ppm; 2 μg/ml) for intervals of 15, 30, 60 and 120 minutes. Controls were incubated in culture medium without cis-Pt (II) . Both the treated and non-treated cultures were then glycerinated and incubated with heavy meromyosin (HMM) (Ishikawa, et al., 1969. J. Cell Biol., 43, 312). Heavy meromyosin was prepared from myosin (Lowery, et al., 1969, J. Mol. Biol., 42, 1) using trypsin as inhibitor. Cell cultures treated with cis-Pt(II) for 30 minutes were also transferred to fresh medium containing 25μg/ml cytochalasin B and 1% dimethyl sulfoxide (DMSO) for 2-24 hours.
Influence of Vagotomy on Duodenal Fat Absorption
Authors: Lamb James C. , Nopanitaya Waykin , Shinoda Brian A. 
Published: June 2020

This study was undertaken to evaluate the effect of unilateral cervical vagotomy on duodenal fat absorption in rats. Increase in fecal fat has been reported following vagotomy. This study demonstrates changes in the duodenal absorptive cell of rats fed vegetable oil when their vagus nerve was previously sectioned on the right side of the neck.Female white rats of a Wistar strain weighing approximately 300 gm were either vagotomized or underwent a sham operation two weeks before tissues were removed for study. The animals were fasted for 48h then fed 2ml Wesson oil through an intragastric feeding tube. One hour later the animals were sacrificed and a segment of the duodenum was removed and processed for transmission electron microscopic analysis.U1trastructural findings in the duodenal epithelial absorptive cells of the sham-operated, oil-fed controls (Fig. 1) were similar to those previously reported.