bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mitochondrial Transformations in the Crayfish Y-Organ During Molt
Authors: Couch Ernest F. 
Published: June 2020

Crustacea, like insects, possess ecdysial glands that produce a hormone governing molting and growth. The hormone is a steriod and the same steroid has been found in insects. The steriod has been given several names, among them are crustecdysone and ecdysterone. The ecdysial glands in insects are named prothoracic glands while the homologous structures in crayfish and other Crustacea are called Y-organs. Y-organs do not always contain the same titer of ecdysterone (Passano and Jyssum, 1963), having the greatest amount of the hormone during the period preceding ecdysis. The cyclical activity of the gland is controlled by a neurosecretory hormone, the molt inhibiting hormone (MIH), released by the sinus gland.Y-organs for this study were obtained from the crayfish, Procambarus simulans. They were fixed with either 3% glutaraldehyde followed by 1% osmium tetroside or simply fixed in buffered 1% osmium. Tissues were embedded in Araldite 502 and prepared for electron miscroscopy. Glands were taken from animals in various periods of the molt cycle.
Cytoplasmic Invaginations in Trophoblasts and Epithelial Cells of Rat
Authors: Baccarini Iracema M. 
Published: June 2020

Some morphological nuclear features (invaginations) in normal and abnormal cells have been described in several electron microscopic studies. They have been referred to by others as blebs, loops, pockets, sheets, bodies, nuclear inclusions and cytoplasmic invaginations. Identical appearing structures were found in cells of the uterine cervical epithelium, in trophoblasts of blastocysts and in trophoblasts of rat placenta.Methods. Uterine cervix (normal rats), rat placenta (9-10 days gestation) and blastocyst were placed in 3% glutarahdehyde for 3 hours. The tissue was washed in phosphate buffer for 24 hours, postfixed in 1%. buffered osmium tetroxide for 1-2 hours and embedded in epon araldite. Sections were double stained with uranyl acetate and lead citrate and viewed in E. M. Siemens 200.Observations. Nuclear invaginations were found in basal, parabasal and mucous cells of the cervix epithelium, in trophoblasts of blastocyst and in trophoblasts of placenta. An oval, round or elongated invagination contained heterogenously cytoplasm surrounded by a double intact membrane; usually several invaginations were found in the same nucleus.
Ultrastructural Changes Associated with Alcoholic Hyalin in Hepatocytes and Biliary Epithelial Cells
Authors: Minick Odell T. , Yokoo Hidejiro , Batti Fawzia 
Published: June 2020

To learn more of the nature and origin of alcoholic hyalin (AH), 15 liver biopsy specimens from patients with alcoholic hepatitis were studied in detail.AH was found not only in hepatocytes but also in ductular cells (Figs. 1 and 2), although in the latter location only rarely. The bulk of AH consisted of a randomly oriented network of closely packed filaments measuring about 150 Å in width. Bundles of filaments smaller in diameter (40-90 Å) were observed along the periphery of the main mass (Fig. 1), often surrounding it in a rim-like fashion. Fine filaments were also found close to the nucleus in both hepatocytes and biliary epithelial cells, the latter even though characteristic AH was not present (Figs. 3 and 4). Dispersed among the larger filaments were glycogen, RNA particles and profiles of endoplasmic reticulum. Dilated cisternae of endoplasmic reticulum were often conspicuous around the periphery of the AH mass. A limiting membrane was not observed.
High Voltage “Electron Petrography” of Lunar Minerals
Authors: Fisher R. M. , Lally J. S. , Radcliffe S. V. , Heuer A. H. , Christie J. M. , Griggs D. T. 
Published: June 2020

Thin sections of selected areas of lunar rocks returned by the Apollo 11 and 12 missions have been studied by high voltage electron petrography (i.e., transmission microscopy). The techniques involved have been described in detail elsewhere.Three of the principle minerals present in the samples, ilmenite (FeTiO3), plagioclase (CaAl2Si208) and clinopyroxene (Fe,Mg,Ca)SiO3, were examined and compared with terrestrial equivalents.Dislocations were evident in all three phases in rock 10029. The arrays, in ilmenite and plagioclase (Figure 1) indicate that mild plastic deformation has occurred. Partial recovery is suggested by hexagonal networks in plagioclase and small dislocation loops in ilmenite. In addition, the plagioclase exhibited extensive twinning and fine precipitates were present in both these phases. “Black spot” images characteristic of radiation damage were found in occasional areas of the plagioclase and pyroxene phases.
Effects of Hyperoxia on Lung Utrastructure
Authors: Harrison Gladys 
Published: June 2020

With the advent of the space age and the need to determine the requirements for a space cabin atmosphere, oxygen effects came into increased importance, even though these effects have been the subject of continuous research for many years. In fact, Priestly initiated oxygen research when in 1775 he published his results of isolating oxygen and described the effects of breathing it on himself and two mice, the only creatures to have had the “privilege” of breathing this “pure air”.Early studies had demonstrated the central nervous system effects at pressures above one atmosphere. Light microscopy revealed extensive damage to the lungs at one atmosphere. These changes which included perivascular and peribronchial edema, focal hemorrhage, rupture of the alveolar septa, and widespread edema, resulted in death of the animal in less than one week. The severity of the symptoms differed between species and was age dependent, with young animals being more resistant.
Intensity Profile of Electron Beam
Authors: Ohr S. M. , Noggle T. S. 
Published: June 2020

In situ studies of electron displacement damage in graphite are being made in Oak Ridge using a 200 kV Hitachi HU 200-E electron microscope. Examples of the damage structure that develops in the area upon which the illuminating beam is incident are shown in Fig. 1. The spot structures (both black and white) are identified as clusters of interstitial atoms. It is of particular interest in this study to have accurate electron dosimetry in order to relate the damage structures to theoretical models. In this paper we wish to report on the technique and some preliminary results obtained in measuring the intensity profiles of the electron beam.Measurements of the beam profiles have been made by replacing one of the side windows of the viewing chamber with a 1” brass plate in which is mounted a retractable arm which can insert a Faraday cup into a position on the axis and at a level approximately one-third the distance from the projector lens to the viewing screen. This arrangement allows one to take pictures with the cup in position, and from the shadow it casts determine its effective area in the magnified image of the beam.
Fine Structural Localization of Acyltransferases Involved in Lipid Synthesis in Intestinal Mucosa.
Authors: Barrnett R. J. , Higgins J. A. 
Published: June 2020

The main products of intestinal hydrolysis of dietary triglycerides are free fatty acids and monoglycerides. These form micelles from which the lipids are absorbed across the mucosal cell brush border. Biochemical studies have indicated that intestinal mucosal cells possess a triglyceride synthesising system, which uses monoglyceride directly as an acylacceptor as well as the system found in other tissues in which alphaglycerophosphate is the acylacceptor. The former pathway is used preferentially for the resynthesis of triglyceride from absorbed lipid, while the latter is used mainly for phospholipid synthesis. Both lipids are incorporated into chylomicrons. Morphological studies have shown that during fat absorption there is an initial appearance of fat droplets within the cisternae of the smooth endoplasmic reticulum and that these subsequently accumulate in the golgi elements from which they are released at the lateral borders of the cell as chylomicrons.We have recently developed several methods for the fine structural localization of acyltransferases dependent on the precipitation, in an electron dense form, of CoA released during the transfer of the acyl group to an acceptor, and have now applied these methods to a study of the fine structural localization of the enzymes involved in chylomicron lipid biosynthesis. These methods are based on the reduction of ferricyanide ions by the free SH group of CoA.
Fine Structure of Armillaria Mellea Hyphae
Authors: Bal Arya K. , Singh Pritam 
Published: June 2020

Armillaria mellea(Vahl ex Fr.) Rummer is an important pathogen, causing “shoe-string”root rot of forest trees; its impact on coniferous plantations in Newfoundland has been realized only recently. Growing interest in the fungus and the disease has led to research on the finer aspects of the pathogen. Attempts to elucidate the ultrastructure of the rhizomorph, have been made recently by Motta and that of the hyphae by Berliner and Duff. The present investigation includes certain aspects of the fine structure of young hyphae, hitherto not dealt with.The fungus was isolated from mycelial fans present under the bark of infected roots ofPicea glauca(Moench) Voss and maintained on 2% Malt extract agar. Peripheral hyphae from 22 days old culture were scraped off from the surface of the medium and fixed in a mixture of paraformaldehyde-glutaraldehyde in Sorensen's buffer pH 7.2. This was followed by post osmication in 1% 0s04 and subsequent Epon embedding.
Preliminary Studies on Heterotopic Calcinosis
Authors: Scott J.R. , Marshall R.B. , Roberts D.K. 
Published: June 2020

Interstitial calcinosis and tumoral calcinosis lesions were studied ultrastructurally and with the use of enzyme cytochemistry. Technics for alkaline phosphatase, acid phosphatase, atpase and aryl sulfatase were utilized after removal of calcium salts with EDTA.Granular elements were seen in both lesions. These granules were seen to lie in cystic spaces of the lesions (Figure 1). Also seen were aggregates of these granules which had apparently calcified (Figure 2). The lesion of tumoral calcinosis had many multinuclear giant cells present peripheral to the cystic spaces with macrophages contributing to the cell population. The lesions all had a pseudocapsule of fibrous connective tissue and “active” connective tissue cells were seen near the cystic space.
Trophoblast Cell Membrane Interactions at Implantation
Authors: Enders A. C. 
Published: June 2020

The alteration in membrane relationships seen at implantation include 1) interaction between cytotrophoblast cells to form syncytial trophoblast and addition to the syncytium by subsequent fusion of cytotrophoblast cells, 2) formation of a wide variety of functional complex relationships by trophoblast with uterine epithelial cells in the process of invasion of the endometrium, and 3) in the case of the rabbit, fusion of some uterine epithelial cells with the trophoblast.Formation of syncytium is apparently a membrane fusion phenomenon in which rapid confluence of cytoplasm often results in isolation of residual membrane within masses of syncytial trophoblast.
Often the last areas of membrane to disappear are those including a desmosome where the cell membranes are apparently held apart from fusion.
Aberrations in the Transmission Electron Microscope
Authors: Ploc R.A. 
Published: June 2020

Three aberrations contribute to the loss of image resolution in the transmission electron microscope; spherical (SA=Csα3), chromatic (CA=Ccα△VV-1) and diffraction (DA=O.61ƛα-1). For high voltage incident electrons and thin materials most microscopists assume resolution is controlled by spherical and diffraction aberrations. We shall discuss whether equating the SA and DA to derive an optimum aperture size (related to αo) and resolution limit (1) is a valid procedure.To determine △V for a given material requires the use of either the Bethe or Landau equations. The Landau formula can be used to give the width of the energy spectrum and the Bethe equation, the mean energy loss after the incident electrons pass through the foil. Since the former is the most probable quantity contributing to CA, Figures 1 and 2 are based on the use of the Landau equation. Zirconium of thickness, t, will be considered for the accelerating voltages 105and 106eV.
Three Dimensional Replication of Fatigue Cracks by Vacuum Infiltration for Study of Crack Tip Morphology by Scanning Electron Microscopy
Authors: Shaw G. G. 
Published: June 2020

I. Introduction: Fatigue investigators have been looking at crack tips by examining the surface and by sectioning the crack. Much useful information has been obtained by these methods, but a look at the complete crack in three dimensions with the tip intact yields much new information. This is especially true when one is able to examine the crack tip in full tension or compression or stages in between, by using the following techniques.II. Vacuum Infiltration in Situ: The crack is generated on a fatigue machine using a sheet sample with a notched central hole. If one desires to replicate in full tension, the machine is stopped in tension and the apparatus shown in Figure 1 is clamped to the sides of the sample.
Creep Induced Twinning in A Γ'-Precipitation Hardened Nickel-Base Alloy
Authors: Kear B. H. , Oblak J. M. , Leverant G. R. 
Published: June 2020

High temperature nickel-base alloys are strengthened by a high volume fraction, coherent precipitate of γ’ [Ni3 (Al,Ti)], with Ll2 structure. The mechanical properties of these alloys are dependent upon the interaction of dislocations with the ordered γ’ precipitate. A detailed diffraction contrast analysis has been made of dislocation/ γ’ particle interactions occurring during 1400oF creep of the nickel-base alloy Mar-M200.In the early stages of creep, two types of γ’ particle shearing mechanisms have been observed, Fig. 1. The interpretation of these micrographs is illustrated in Fig. 2.
Transmission Electron Microscopy of Terrestrial Rocks and Minerals
Authors: Inman Maurice C. 
Published: June 2020

Comprehensive application of transmission electron microscopy (TEM) to rocks and minerals has been made possible by the recent introduction of reliable ion beam thinning devices. The potential of TEM as a diagnostic tool for evaluation of the thermal history, mode of formation, age and general environment of both terrestrial and lunar materials is a matter of considerable present interest. Studies of terrestrial basalts and volcanic glasses at this University have recently revealed that TEM can provide information of considerable diagnostic significance, a specific example of which is given below.Figure 1 is a view of twin bands which we have commonly observed in the plagioclase (Labradorite) component of an olivine basalt from the Cascade Mountains, Oregon. The twin planes are defined by parallel light and dark contrast fringes, and selected area diffraction indicates that we are observing albite twins with composition plane (010). Of particular interest is the morphology of the albite twins at region A. For purposes of comparison, Fiqure 2 reproduces the characteristic appearance of a growing annealing twin in the metal nickel.
Crystallinity of Liquid-Like, Vapor-Deposited Tin Films
Authors: Murr L. E. 
Published: June 2020

In a previous paper, Singh and Murr described the vapor-liquidsolid phase growth of Sn thin films according to the conventions originally outlined by Semenov and Komnik. More recently, Singh and Murr also quantitatively outlined the nucleation and growth characteristics of vapor-deposited Sn thin films and concluded that the results were indicative of a recrystallization process involving the supercooling of liquid drops as described earlier by Takagi.The present study involves a rigorous examination of the nature of the solidified liquid-like Sn clusters following vapor deposition onto air-cleaved NaCl (001) substrates for the condition Ts≥2/3Tm; where Ts and Tm are the substrate temperature and the melting temperature of the Sn in °K respectively.
Characterization of Sputtered Films using the Scanning Electron Microscope
Authors: Schneidmiller R. F. , Thrower W. F. , Ang C. 
Published: June 2020

Solid state materials in the form of thin films have found increasing structural and electronic applications. Among the multitude of thin film deposition techniques, the radio frequency induced plasma sputtering has gained considerable utilization in recent years through advances in equipment design and process improvement, as well as the discovery of the versatility of the process to control film properties. In our laboratory we have used the scanning electron microscope extensively in the direct and indirect characterization of sputtered films for correlation with their physical and electrical properties.Scanning electron microscopy is a powerful tool for the examination of surfaces of solids and for the failure analysis of structural components and microelectronic devices.
Technique for Visualizing Subgrain Structure at Fatigue Crack Tips by Ion Etching and Scanning Electron Microscopy
Authors: Shaw G. G. , Benson D. K. 
Published: June 2020

The subgrain structure in ram size areas adjacent to fatigue cracks has been observed by ion etching followed by scanning electron microscopy. The etch patterns have been definitely identified as subgrain structure resulting from the fatigue strains by direct comparison with channelling electron microscopy. The technique is described as it was applied to a single crystal of aluminum which had been fatigued in Stage I by reversed bending.A 5 mm long section of crystal containing the crack was cut from the fatigue sample by spark machining. This section was sliced into pieces 2 to 3 mm thick, and a slice selected with the crack tip close to its center. The selected slice was placed in a shallow aluminum cup about 2 cm in diameter.
Effects of a Modified Wehnelt Grid Assembly on Electron Microscope Image Contrast
Authors: Maher D. M. , Tanaka A. 
Published: June 2020

The need for higher brightness electron sources with improved coherence has been appreciated for some time by electron microscopists and electron optical manufacturers. The results given in this paper suggest that changes in these electron source characteristics can be expected to influence the image quality of lattice defects taken under two-beam dynamical conditions in thick crystals.In this study stacking faults and bounding partial dislocations in silicon were imaged at various crystal thicknesses using JEM 200 electron microscopes operated at 200 kV. linages were, obtained using microscopes equipped with a normal Wehnelt grid assembly and a modified assembly. In both cases a standard hair-pin filament was used. The modified Wehnelt assembly (so-called Cool beam assembly) differs from the normal one both in shape and filament position.
The Third Dimension in Scanning Electron Microscopy: Scanning Auger Microscopy
Authors: MacDonald Noel C. 
Published: June 2020

During the past few years, Auger Electron Spectroscopy (AES) has been successfully applied to solving many practical surface chemistry and thin film problems. When used as a surface chemical analytical tool, AES identifies chemical elements present in the first 5-50 Å of a solid surface. The combination of AES and ion sputter etching is used to chemically profile thin films with an in-depth resolution of better than 10% of the thickness of the film. Examples of chemical profiles will be presented which illustrate the good in-depth spatial resolution obtainable using AES combined with ion sputter etching.In the past, the lateral spatial resolution has been limited by the electron gun available in commercial AES equipment.
Morphology, Distribution and Identification of Micro-Constituents Along Grain Boundaries in Nickel-Base Alloys
Authors: Fornwalt D. E. , Geary A. R. , Kear B. H. 
Published: June 2020

A systematic study has been made of the effects of various heat treatments on the microstructures of several experimental high volume fraction γ’ precipitation hardened nickel-base alloys, after doping with ∼2 w/o Hf so as to improve the stress rupture life and ductility. The most significant microstructural chan§e brought about by prolonged aging at temperatures in the range 1600°-1900°F was the decoration of grain boundaries with precipitate particles.Precipitation along the grain boundaries was first detected by optical microscopy, but it was necessary to use the scanning electron microscope to reveal the details of the precipitate morphology. Figure 1(a) shows the grain boundary precipitates in relief, after partial dissolution of the surrounding γ + γ’ matrix.
Interfacial Stability and Mechanical Behavior of Nichrome-Tungsten Filamentary Composites
Authors: Burden S. J. , Lawley A. 
Published: June 2020

Filamentary composites are frequently fabricated by an elevated-temperature process such as diffusion bonding. Because of differences in chemical potential of the elements at the interface, processing or subsequent elevatedtemperature exposure is accompanied by interdiffusion and/or reaction. Generally, this is reflected in the degradation of mechanical properties since it is the interface that controls stress transfer from matrix to reinforcement. The purpose of this study was to characterize the interfacial dependence of mechanical behavior in potential high-temperature nickel-alloy matrix composites reinforced with refractory metal wires, and to determine the effectiveness of diffusion barrier layers between fiber and matrix.Tungsten wire-reinforced nichrome composites (Vf in range 10% to 20%; wire diameter 0.010“) were diffusion bonded under vacuum for one hour at 1100°C.
Test Specimens For High Resolution Scanning Electron Microscopy
Authors: Greer Raymond T. 
Published: June 2020

A useful resolution specimen for day-to-day SEM instrument standardization should exhibit uniform, periodic microstructure of hundreds to thousands of angstroms, show low contrast, have low cost, be easily prepared, and demonstrate long term stability.Opal (Figure 1) is particularly useful as a resolution specimen; however, several aspects of sample preparation should be emphasized. A high quality gem opal chip a few millimeters in diameter is sufficient for carefully controlled etching in, for example, 10% HF for 30 seconds. The choice of test specimen microstructure size is established by the maximum wavelength of color observed under white light. The iridescence effect is dictated by the microstructure of uniform silica spheres arranged in a cubic closest packing array.
Characterization of Tamm-Horsfall Urinary Glycoprotein
Authors: Robinson John P. , Puett J. David 
Published: June 2020

Much work has been reported on the chemical, physical and morphological properties of urinary Tamm-Horsfall glycoprotein (THG). Although it was once reported that cystic fibrotic (CF) individuals had a defective THG, more recent data indicate that THG and CF-THG are similar if not identical.No studies on the conformational aspects have been reported on this glycoprotein using circular dichroism (CD). We examined the secondary structure of THG and derivatives under various conditions and have correlated these results with quaternary structure using electron microscopy.THG was prepared from normal adult males and CF-THG from a 16-year old CF female by the method of Tamm and Horsfall. CF female by the method of Tamm and Horsfall.