bluuebunny/crossref_metadata_2025_split huggingface dataset:
TEM Observations of Vanadium Carbide Reversion in an HSLA Steel
Authors: Locci I. E. 
Published: June 2020

Microalloy precipitates in HSLA steels have relatively high equilibrium solubility temperatures. Being equilibrium phases, they are not normally associated with precipitate reversion processes. However, a recent observation has indicated that VC precipitate reversion may occur when HSLA steels are subjected to rapid heat treatment cycles. This investigation sought to determine if VC reversion occurs during rapid austenitization heat treatment cycles applied to a.14 wt% C,.48 wt% Mn and.49 wt% V HSLA steel.As-hot-rolled strips of the alloy were cut into sections VL cm by ∼0.5 cm thick. The equilibrium solubility temperature of VC in this alloy is 1037° C. Samples were initially solution treated at 1150°C for 1/2 hour, then quenched in iced brine solution to produce low carbon martensite.
Micro Beam Orientation Determinations in Highly Deformed Cu - 12.5% Ni Alloy
Authors: Caceres P.G. , Garwood R.D. 
Published: June 2020

Convergent beam microdiffraction (CBD) techniques have been used to determine changes in orientation along and across subs truetural regions such as microbands, shear bands, crystallites, etc., in a heavily cold rolled Cu - 12.5% Ni alloy of high purity. The investigation is an extension of similar studies on copper and alpha brass (see eg. 1, 2 and 3).Pole figures and inverse pole figures determined by x-ray diffraction techniques have shown (see 4 and 5) that this alloy develops a copper-type deformation texture, although, more slowly than the pure metal since a substantial increase of the 422 reflection, arising from a (112) [111] end orientation, occurs only at deformations greater than 90% (ε ∼2.30).
High-Resolution STEM Characterisation of Discontinuous Precipitate Products in Aluminum-Zinc
Authors: Solórzano G. 
Published: June 2020

Discontinuous precipitation is an interface diffusion-controlled transformation resulting from the decomposition of a supersaturated parent phase α° to yield generally a lamellar second phase 8 and a less-supersaturated matrix α'. The main transformation interface is therefore a grain boundary which acts as a fast diffusion path, enabling the required composition to change at temperatures too low for appreciable volume diffusion. The practical importance of this transformation, present in a large number of alloy systems, is related to the degradation of precipitation hardening microstructures, wherein an otherwise long lived microstructure is discontinuously coarsened by the sweeping grain boundaries.The Kinetic and thermodynamical aspects of the steady state transformation has been Know, in theory, for many years. The theory predicts that the grain boundary-reaction front is capable of supporting a composition difference across it and a composition gradient along it.
Titanium-Suicide Contacts on GaAs
Authors: Liliental Z. , Wakita A. , Kocot C. , Washburn J. , Gronsky R. 
Published: June 2020

Successful use of titanium silicides as contacts on Si suggested the possibility of their application as Schottky contacts on GaAs. One composition of Ti:Si with the ratio 1:3 annealed for 5 sec at 875°C was found to result in good Schottky contacts. The barrier height and ideality factor were 0.8 eV and 1.15, respectively. The same heat treatment procedure for the composition of Ti:Si 1:2 did not give satisfactory electrical parameters.Cross section samples were prepared from these contacts for both compositions and were examined in a JEOL 200 CX electron microscope. Energy dispersive X-ray (EDX) and electron energy loss spectra (EELS) were taken using a Phillips 400 FEG electron microscope at 100 KV accelerating voltage.As-deposited structures with Ti:Si ratios 1:2 and 1:3 consisted of four alternate Ti and Si layers with different thicknesses. The interface of the first Ti layer with GaAs was very flat and abrupt for both compositions.
Electron Microscopy of Barium-Promoted Copper Chromite
Authors: Hall J. B. , Kouba J. K. 
Published: June 2020

Copper chromite was reported as an effective catalyst for the hydrogenation of esters to alcohols by Homer Adkins in 1931, and it still remains the catalyst of choice for this reaction. Its most common commercial application is in the hydrogenation of fatty esters to detergent range linear alcohols. Typical reaction conditions are relatively severe: 200-250°C and 2000-4000 psig hydrogen. Barium is often used as a promoter and such a catalyst is prepared by codeposition of barium and copper chromates followed by calcination to the mixed chromite. The catalyst is usually activated by reduction with hydrogen which is believed to generate highly dispersed copper metal. The barium supposedly retards overreduction of the catalyst and ameliorates sulfate poisoning.Knowledge of the distribution and association of the Ba, Cu, and Cr catalyst components is important in understanding its function and in the design of better catalysts.
Microanalysis of Radiation-Sensitive Semiconductor Interfaces
Authors: O.L. Krivanek  , Liliental Z. 
Published: June 2020

Owing to the success of high resolution electron microscopy (HREM), the structure of the most important semiconductor interfaces is now relatively well known on a scale of about 0.3nm. What is frequently missing, however, is information on the chemical composition on a similar scale.The spatial resolution of conventional depth-profiling, broad-beam techniques (Auger, ESCA, ion scattering) is usually limited to about 3nm normal and several PM parallel to the interface. High resolution microanalysis of cross-sectional samples by EELS and EDXS in a field emission STEM instrument is limited by the probe diameter and spreading, and the de-localization of inelastic scattering to about 2nm (theoretically), both normal and parallel to the interface. However, to obtain such a resolution, doses of the order of 108 to 1010 electrons/ nm2 are required. In semiconductors and particularly in oxides such doses lead to significant radiation damage and mass loss, often to the point of perforation of the sample.
Time-Resolved Electron Energy Loss Spectroscopy on Copper Oxides
Authors: Long N.J. , Skiff W.M. , Higgs A. , Carpenter R.W. , Lyman C.E. 
Published: June 2020

In a previous paper it was shown that it is possible to distinguish CuO from Cu metal in a CuO/ZnO catalyst. It was also observed that the CuO showed signs of reduction under the impact of the high current density used in a field emission UHV STEM. This work reports on the efforts so far to study the changes in the L3, 2 edge of Cu as a function of time and hence ultimately to determine the kinetics of whatever radiation damage process is responsible for the changes observed in the catalyst CuO.The first problem to be overcome was to provide a multichannel analyzer system capable of recording the same region of an ELS spectrum repeatedly and yet retain the individual scans. A Kevex 7000 series computer/MCA system was modified and software written which enables the user to select a region of a normal spectrum for subsequent analysis. An additional D to A converter, plus modified Gatan ELS spectrometer electronics, provided the means to offset the spectrometer magnet by an amount equal to the chosen windows so that the same energy window would be scanned sequentially. The electron microscopy was performed using a Philips EM400ST with a field emission gun at 100kV.
An Analysis Of Residual Asbestos Remaining In Preparative Vials Following Bleach Digestion
Authors: Corn C. J. , Williams M. G. , Dodson R. F. 
Published: June 2020

A continual question that concerns researchers using digestion techniques for the study of asbestos load in tissue is, “What percentage of the total fibers remains adhered to the walls of the preparative vials after digestion?“In order to get a perspective on this problem, a test series was established which enabled us to define this residual fiber content following several variations in the rinsing procedure. The test material for all studies was a digested piece of lung tissue from a former asbestos worker. The digestion procedure used was based on the bleach digestion technique presented by Smith and Naylor. This tissue contained 3x108 fibers and 8x105 ferruginous bodies per gram and had a fiber per ferruginous body ratio of 37.5. Aliquots (1.5 ml) of the digest were used to create reproducible standards.
Technical Evaluation of Four Common Embedding Resins Used in Electron Microscopy
Authors: Juengel L.I. , Uphoff C. , Cole T.B. 
Published: June 2020

Today, numerous types of embedding media are available for use in the electron microscopy laboratory. Laboratories generally choose a particular embedding media based on their own practical experiences with it. This study was performed to compare and evaluate four common resins found in electron microscopy laboratories.Skeletal muscle was removed from rats perfused with 3% glutaraldehyde in 0.1M collidine, cut into rectangles and allowed to remain in fixative for 6 hours. Tissue was then washed in 0.1M collidine buffer and post fixed for 1 hour with 1% osmium tetroxide in 0.1M collidine. After rinsing in collidine buffer the tissue was divided into groups for processing according to established procedures for the following resins: Araldite, Epon, Mollenhauer, Spurr (see formulas).
Rapid Specimen Preparation Using Microwave Energy
Authors: Baldwin F. , Diocee M.S. 
Published: June 2020

In recent years the feasibility of using microwave energy to fix tissue and expedite histologic staining has been tested. The technique has proven to be particularly valuable for shortening staining time of light microscopy preparations', thus enabling more rapid diagnosis which may be critical to patient care.Rapid preparation of tissue for electron microscopy is often desirable in diagnostic ultrastructural pathology but with techniques commonly in use several hours may elapse before epoxy resin blocks reach a consistency suitable for ultrathin sectioning.In this laboratory, microwave energy has been used to polymerise epoxy resin and the usefulness of the technique has been evaluated.Kidney, liver and lung from male Wistar rats were fixed in phosphate buffered glutaraldehyde, cacodylate buffered glutaraldehyde and universal fixative.
Rapid Processing for Diagnostic Electron Microscopy Using an Epon Replacement-Embed 812
Authors: Woods William J. , Ucci Angelo A. 
Published: June 2020

Shortened turnaround time is a definite advantage in a diagnostic laboratory. It has been our experience that following a good initial fixation we can and do routinely rapid process our biopsies and surgical specimens for electron microscopic study. Surgical residents and consulting hospital personnel are instructed to send to our laboratory 1-2mm slices of appropriate areas of tissue (not necrotic) in Trumps 4CF-IG fixative. Specimens can be held in this solution without appreciable loss of ultrastructural detail until we can process them further. The processing schedule is listed below.The specimen after at least 15 minutes in fixative is minced into cubes, slightly smaller than 1mm on a side, and processed according to the following shortened time schedule.
Ultrastructural Kinetics of Electrically Induced Fusion of Human Erythrocytes
Authors: Stenger D.A. 
Published: June 2020

Conditions for electrical breakdown and subsequent fusion of biological membranes have been reported for a variety of eukaryotic cell systems. Large fusion yields may be obtained by first causing cells to form pearl chains parallel to the electric flux lines in a high frequency a.c. field by a process known as dielectrophoresis. The dielectrophoretic force affords close positioning of the cells and facilitates maintenance and expansion of intercellular membrane and cytoplasmic contiguity initiated by one or more sharp square pulses directed through the pearl chains. Reversible disruption of the cell membrane occurs when the compressive electrical force caused by the square pulse exceeds a critical value.This investigation focused on elucidating the ultrastructural kinetic mechanism(s) involved in the electrically-induced fusion of human erythrocytes. In this case, rapid freeze copper sample holders for freeze-fracture were incorporated as electrodes into a circuit capable of performing the type of protocol described above (Fig. 1). Washed human erythrocytes were suspended in 0.3 M sucrose containing 25.7 μm latex beads for electrode separation.
Is Smooth Endoplasmic Reticulum Involved in Hepatic Glycogen Synthesis in the Fetal Mouse?
Authors: Breslin Joanette S. , Robert R. Cardell  
Published: June 2020

Considerable evidence suggests that hepatic smooth endoplasmic reticulum (SER) functions in both glycogen deposition and depletion and is closely associated with glycogen particles during both processes in the adult rodent liver. In this study we have investigated the time course of hepatic glycogen deposition and examined the association of SER with glycogen particles during fetal glycogen synthesis, i.e., from day 15 to day 19 of gestation (plug day = day 1).Livers were removed from fetal ICR mice and processed for either light (LM) and electron microscopy (EM) or biochemical determination of glycogen. Biochemical analysis of glycogen concentrations in each liver revealed an average of 0.1% glycogen in day 15 and day 16 fetal livers, 0.6% in those from day 17, 2.0% on day 18 and nearly 5.0% by day 19. Light microscopic analysis of periodic acid-Schiff (PAS) stained semi-thin (1.0μm) sections confirmed the presence of increasing amounts of glycogen beginning on day 16 and reaching a maximum on day 19 of gestation.
Extracellular Cylindrical Rod Structures in a Sparganum, Tape Worm Larva, of Human Host Origin
Authors: Sun C. N. 
Published: June 2020

Banded and laminated structures have been reported in human and animal tissues in the extracellular space. To my knowledge, extracellular cylindrical laminated rod structures have not been previously reported in the animal tissues. In the study of a sparganum (spirometra Sp) this unusual structure was found.A sparganum in a nodule from the outer aspect of the right thigh of a 30 year old male in Arkansas has recently been described which is believed to be either S. mansonoides or S. mansoni. The worm, which was 90 mm long and 1 mm wide, was fixed in neutral buffered formalin and post-fixed with buffered 2 percent osmium tetroxide. The tissues were then dehydrated in serially increasing concentrations of ethanol and embedded in Epon 812. Sections were stained with uranyl acetate and lead citrate.
Isolation, Electron Microscopy, and Computer Processing of Chromosomes
Authors: Mazzone H.M. 
Published: June 2020

Computer processing of electron microscope images has been of great value in the delineation and correlation of structural characteristics. An appropriate system for such study is that which enhances the high spatial frequency components in an image, thereby assisting in the observation of its fine structure. The present study reports on the isolation of intact chromosomes from a mammalian cell culture and their examination in the transmission electron microscope. The images of the chromosomes were then enhanced by computer processing.Isolation of the chromosomes and their examination in the electron microscope was done in the Dept, of Biology of the Massachusetts Institute of Technology. A mammalian cell line, STR-T, was maintained under standard conditions. Fresh cultures were prepared and when the cells were in log phase, colchicine was added to arrest the chromosomes at metaphase. After chemical fixation with ethanol-acetic acid (3:1), the cells were mechanically dislodged by scraping the vessel surface with a rubber policeman. The cells were place in a test tube and gently homogenized by hand.
The Effect of Benzene on Bluegill Olfactory Lamellae
Authors: Mattie D.R. , Fisher J.W. 
Published: June 2020

Jet fuels such as JP-4 can be introduced into the environment and come in contact with aquatic biota in several ways. Studies in this laboratory have demonstrated JP-4 toxicity to fish. Benzene is the major constituent of the water soluble fraction of JP-4. The normal surface morphology of bluegill olfactory lamellae was examined in conjunction with electrophysiology experiments. There was no information regarding the ultrastructural and physiological responses of the olfactory epithelium of bluegills to acute benzene exposure.The purpose of this investigation was to determine the effects of benzene on the surface morphology of the nasal rosettes of the bluegill sunfish (Lepomis macrochirus). Bluegills were exposed to a sublethal concentration of 7.7±0.2ppm (+S.E.M.) benzene for five, ten or fourteen days. Nasal rosettes were fixed in 2.5% glutaraldehyde and 2.0% paraformaldehyde in 0.1M cacodylate buffer (pH 7.4) containing 1.25mM calcium chloride. Specimens were processed for scanning electron microscopy.
From Frozen Section to HVEM: Prospects For Enhanced Pathologic Characterization of Single Invading Cells With Ultrastructural Information
Authors: Vernon King Murray , Parsons Donald F. 
Published: June 2020

Identification of single cells in frozen sections of tissue in the light microscope (LM) with subsequent reprocessing for examination in the high-voltage electron microscope (HVEM) for ultrastructural characterization offers an expedient route for studying such processes as the dissemination of cancers by single-cell invasion. The HVEM combines a high resolution that enables more certain identification of a cell and assessment of its activity at the instant of fixation with the convenience of an allowed thickness range (0.25-2.0 μm) close to that employed by the pathologist using the LM.Employment of frozen sections allows adequate ultrastructural preservation, while at the same time enabling recognition of specific cell types by immuno-histochemistry or enzyme histochemistry. Only very brief aldehyde fixation is required—about four minutes. After reembedding, tissue containing marked cells is dissected out for reprocessing for the HVEM. Ultrastructural examination in turn enables more detailed identification and characterization of cell types. The LM staining process is illustrated with results from immuno-histochemical recognition of single invading squamous carcinoma cells in head-and-neck cancer.
Nanosecond Exposure Time Soft X-Ray Contact Imaging
Authors: Rosser R. J. 
Published: June 2020

Soft x-ray contact microscopy has been pursued for many years because of the potential advantages of 1 to 10 nm electro-magetic radiation for imaging biological materials. These are the lower damage and greater penetration than electrons and considerably higher resolution than visible light microscopy, both possible without exotic optics.The technique is similar to contact printing. The object to be viewed is placed as close as possible to the recording medium which is then exposed to a suitable x-ray source.. The sample is removed from the recording medium which is then chemically developed. The result is map of the x-ray opacity of the original specimen.The high resolution has only become reality in recent years with the use of x-ray photo-resists as the recording material. These were origionally developed for use in the electronics industry but have been used for contact images of biological material.
Surface Changes in Vaginal Epithelial Cells During Persistent Estrous Rats
Authors: Francis K. Khosho , Robert C. Kaufmann , Kofi S. Amankwah 
Published: June 2020

Light exerts a major influence on the reproductive functions of the female rat, and the presence of constant light results in an aberrant vaginal cycle, leading to infertility associated with polycystic ovary (PCO) syndrome. In the present communication, we have utilized scanning electron microscopy (SEM) to study changes on the surface epithelium of persistent estrous (PE) rats with PCO.Sprague-Dawely female rats were exposed to constant light for 50-150 days according to protocol that has been previously described. Rats in normal estrous, as determined by vaginal smears, were used as controls. Nembutal- anesthesized rats were perfused through the aorta with 2.5% gluteraldehyde in 0.1M sodium cacodylate buffer (pH 7.3). The mucosa of the upper third of the vagina from PE and control rats were microdissected, processed for SEM studies by a modified 0T0T0 technique, dehydrated, and critical point dried with C02- The specimens were examined in a Hitachi scanning electron microscope Model S-500.
Sinusoidal Cells in Bone Marrow Take Up BSA-Au Conjugates in the Presence of an Artificial Blood Substitute
Authors: Geoffroy J.S. , Becker R.P. 
Published: June 2020

The pattern of BSA-Au uptake in vivo by endothelial cells of the venous sinuses (sinusoidal cells) of rat bone marrow has been described previously. BSA-Au conjugates are taken up exclusively in coated pits and vesicles, enter and pass through an “endosomal” compartment comprised of smooth-membraned tubules and vacuoles and cup-like bodies, and subsequently reside in multivesicular and dense bodies. The process is very rapid, with BSA-Au reaching secondary lysosmes one minute after presentation. (Figure 1)In further investigations of this process an isolated limb perfusion method using an artificial blood substitute, Oxypherol-ET (O-ET; Alpha Therapeutics, Los Angeles, CA) was developed. Under nembutal anesthesia, male Sprague-Dawley rats were laparotomized. The left common iliac artery and vein were ligated and the right iliac artery was cannulated via the aorta with a small vein catheter. Pump tubing, preprimed with oxygenated 0-ET at 37°C, was connected to the cannula.
Gene-Specific Labeling For An Electron Microscopic Study of Chromosomal Proteins
Authors: Varkey Jacob , Hannibal Mark , Brantley John , Stewart Brian , Beer Michael 
Published: June 2020

With the aim of understanding the control of gene expression we are developing techniques to study the proteins bound to particular genes at various stages of activity. To accomplish this we have worked out a gene specific labeling procedure and are testing it with the 5S RNA genes of Xenopus.Our approach is based on the gene specific purification proposed by Workman and Langmore (1984). Chromatin is digested with a suitable restriction enzyme followed by lambda exonuclease to yield a protruding 3’ end. DMA from the same gene is cut with the same restriction enzyme and nick translated with biotin-dUTP. Then it is digested with exonuclease III to produce a protruding single strand complementary to that of the chromatin. Probe and chromatin are annealed to each other under gentle conditions (0. 1m NaCl; 37°C), Avidin linked to Ferritin is added to decorate the biotin containing regions of the probe and the material is examined in the electron microscope. The chromatin pieces of interest can be recognized by the attached Ferritin labeled probe.