bluuebunny/crossref_metadata_2025 huggingface dataset:
Surface Damage of Delustered Nylon 66 Fibers Exposed to Light
Authors: Zeronian S. H. , Tomioka M. K. , Pangborn J.
Published: June 2020

Zeronian, using a scanning electron microscope-(SEM), found that when nylon 66 fabric was exposed simultaneously to light from a xenon arc lamp, and to air, and periodically sprayed with water, pits appeared on the surface of the semidull fibers. The size and number of the pits increased with time of exposure.

In the present study, we examined the influence of TiO2 on the surface structure of 70-34-Z DuPont nylon 66 filament yarn exposed to light. Bright, semidull, and dull forms were used at respective TiO2 concentrations of 0.02, 0.30, and 2.0%. The yarns were exposed simultaneously to light and air in a Weather-Ometer, and were sprayed with water for 18 min every 2 hr.
The Future of Sputtering in the Electron Microscope Laboratory
Authors: Paulson G. G. , Ferrell R. E.
Published: June 2020

In such fields as electronics and optics, the sputtering process is rapidly displacing the conventional evaporation process. Its major advantage is the ability to deposit a variety of refractory metals and dielectric materials with good control and reproducibility. This advantage and numerous others are valid reasons why sputtering may eventually displace thermal evaporation in the typical electron microscope laboratory. Sputtering is readily adapted to the procedures utilized in TEM, however, the following discussion highlights the advantages of sputtering for applying coatings to specimens for SEM.

Sputtering is not a new concept. Numerous papers and books had been published before 1900 concerning the use of sputtering for depositing thin films.
The Stress Induced Martensite-Austenite Interface in Fe-15Ni-15Cr Single Crystals
Authors: Stone G. A. , Thomas G.
Published: June 2020

A single crystal stressed in the [3]𝛄 direction at 185°K was transformed to 5% 𝛂 martensite and 2% Ɛ martensite by volume. The austenite slip system of maximum shear stress is the (11)𝛄 [01)𝛄. Fig. 1 shows a two surface study using the electron and optical microscopes. The a martensite is confined between £martensite plates with the (0001)Ɛ ∥ (11)𝛄. The size of the acicular martensite crystals is controlled by the spacing of the £ martensite plates. These £ martensite plates are seen in Fig. 1A as dark vertical bands. The axes of the acicular crystals lie in the (11)𝛄 plane. The £ martensite habit plane is defined as the plane perpendicular to the (11)𝛄 containing the vector defining the crystal axis.
Scanning Electron Microscopy Study of Gold-Refractory Thin Film Reliability
Authors: Day H. , Christou A.
Published: June 2020

In recent years, efforts to increase the reliability of microwave power transistors has led to the investigation of more suitable metallizations which can withstand the high temperatures encountered in these devices without causing degradation or failure due to alloying or the interdiffusion of silicon, silicon dioxide and metal. In the present paper we report the results of an SEM study of surface reconstruction and degradation at elevated temperatures in thin films of Au-Ta, Au-Ta-Pt, Au-Ta-Pd, Au-W and Au-Mo due to reagent contamination. The contaminants originated from a conventional oxide etching solution. The extent of subsequent rinsing was used as a measure of contamination.
A Photoemission Electron Microscope using an Electron Multiplier Array
Authors: Baxter William J. , Rouze Stanley R.
Published: June 2020

We have converted a Philips thermionic emission electron microscope into a photoemission electron microscope by adding a simple ultraviolet illumination system, and a Channeltron Electron Multiplier Array (CEMA) for image intensification. This microscope provides photoemission images with or without heating of the sample, without removal of the surface oxide, and without activation. We illustrate with two examples: 1) a photoemission image of nickel, and 2) the first direct images of the exoelectron emission produced by abrasion of a metal surface.

The microscope consists essentially of an electrostatic lens and two magnetic lenses. The immersion electrostatic lens is formed by the specimen, the Wehnelt cap at −15 kV, and the anode at ground potential.
Auger Electron Emission Micrography and Microanalysis of a Stained Surface of Pure Iron Plate
Authors: Hayakawa K. , Okano H. , Kawase S. , Yamamoto S.
Published: June 2020

A new primary beam scanning Auger electron energy analyser was constructed. The primary electron energy is variable in the energy range from 1 KeV to 10 KeV. The diameter of the primary beam is about 2 μm at 9 KeV. Using this apparatus, Auger emission microanalysis was carried out on the surface of the various solid matters by selection analysing points in the absorbing current image of the specimen surface. In addition, by synchronizing the scanning of the primary beam on the specimen surface with the flying spot of a CRT, Auger emission micrograph (AEM) was obtained as the brightness modulation due to a particular Auger spectral line emitted from the specimen.
Precipitation Hardening in Gold-Titanium Alloys
Authors: Graham M.
Published: June 2020

The strength of gold alloys can be improved through heat treatment. Our previous work demonstrated an eight-fold increase in yield strength from the as-quenched to the maximum age-hardened state of a Au-4 at.% Ti alloy. This increase is attractive in terms of developing stronger gold alloys for clinical use and for studying strengthening mechanisms.

Observations of yield stress as a function of aging treatment and test temperature, and on the nature of the yielding (serrated) allowed us to deduce a physical model of the strengthening mechanism. Concurrent transmission electron microscopy provided direct evidence about the structural changes accompanying heat treatment and about the modes of deformation. The results presented here illustrate the change in internal structure with precipitation and the resulting change in mechanical properties.
On the Origin of Recrystallization Texture
Authors: Rath B. B. , Hu H.
Published: June 2020

The recrystallization process involves the nucleation and growth of strain-free grains and results in grain orientations which are grossly different from those in the deformed matrix. The texture developed during recrystallization has been attributed either to the oriented nucleation or to the oriented growth mechanisms. Although the orientation dependence of the growth rates of recrystallized grains is well recognized, the crystallographic relationships between the grain nuclei and the matrix are not clearly understood.

The origin of recrystallization texture has been investigated in detail by examining the orientations and the size of the stable nuclei and their relation to those of the surrounding matrix.
Observation of Sub-Lattice Dislocation Pairs in an Improved High Temperature Protective Coating Alloy
Authors: Tzeng Wen-Shian , Strutt P. R. , Polvani R. S.
Published: June 2020

A twenty-fivefold enhancement in the creep strength of nickel aluminide (NiAl) has been made by specific selection of a transition metal atom addition (Ti). The titanium addition in strongly favoring formation of the extremely stable Ni2A1Ti Heusler type phase gives rise to an alloy with a continuous Ni2AlTi phase containing a distribution of large NiAl ppts., see fig. 1. In the heat treated and undeformed alloy the lattice mismatch (−1%) is accommodated by two orthogonal sets of ao<100> dislocations. However, as creep ensues, these interfacial boundaries absorb glide dislocation to produce more complex networks of the type shown in fig. 1.
Phase Transformations in Ti-15w/OMo-3w/oAl
Authors: Kannan V. C. , Fujishiro S.
Published: June 2020

The effect of additional alloying elements on the decomposition of metastable beta titanium alloys during isothermal aging has received much attention for the past few years. Aluminum, which is an a-stabilizer, was shown to effectively retard the formation of ω-phase and accelerate 𝛂-nucleation. It was proposed by previous investigators that complete suppression of ω-phase in titanium alloys, with large amounts of the alloying elements, leads to the decomposition of ω-phase through an intermediate phase separation reaction. In the present studies, phase transformations in Ti-15w/oMo-3w/oAl were investigated using X-ray diffraction and transmission electron microscopy.
Vapor-Liquid-Solid Whisker Growth on Lunar Breccia 15015
Authors: Carter James L. , Crosthwait D. L.
Published: June 2020

Possible VLS (Vapor-Liquid-Solid) whisker growth has been discovered for the first time in nature on the surface of lunar breccia 15015. Rock 15015 was collected on the Apollo 15 flight and is blocky, angular, largely glass-covered, almost 30 cm long and weighs 4.5 kg. A 62 mm2 glass-covered surface of a fragment of 15015 (15015,36) was coated with 150 Å of Au and selected areas studied in detail with a JEOLCO JSM-1 scanning electron microscope (SEM), an ARL scanning electron microprobe (EMX SM) with a QANTA/METRIX energy dispersive spectrophotometer and a Cambridge MK IIA SEM at Texas Instruments, Inc. of Dallas.
Resolution Attainable With the Present Day STEM
Authors: Wall J. S. , Langmore J. P. , Isaacson H. , Crewe A. V.
Published: June 2020

The scanning transmission electron microscope (STEM) constructed by the authors employs a field emission gun and a 1.15 mm focal length magnetic lens to produce a probe on the specimen. The aperture size is chosen to allow one wavelength of spherical aberration at the edge of the objective aperture. Under these conditions the profile of the focused spot is expected to be similar to an Airy intensity distribution with the first zero at the same point but with a peak intensity 80 per cent of that which would be obtained If the lens had no aberration. This condition is attained when the half angle that the incident beam subtends at the specimen, 𝛂 = (4𝛌/Cs)¼
Considerations in Making Stereo Micrographs With the Scanning Electron Microscope
Authors: Walter E. R.
Published: June 2020

The information obtainable with the scanning electron microscope can often be increased severalfold through the use of stereomicrograph pairs. Not only is the detail which can be observed the equivalent of a 2X increase in magnification over that apparent in a single micrograph, but, threedimensional spatial relationships are more accurately preserved. This is especially true where protruding or pyramided fine structure and/or gross reentrance exists. Since stereo micrographs are conveniently obtained with most scanning electron microscopes, it is generally desirable to add the additional information they offer whenever the three-dimensional relationships present in the specimen'are not readily apparent.
Energy Filtering in Electron Microscopy and Electron Diffraction
Authors: Castaing R.
Published: June 2020

Energy filtering has proved to be a most valuable tool in electron microscopy. By the simple introduction of a dispersive device in the column of the electron microscope, it is possible to select quite easily, for the production of the image, those of the electrons which have suffered, when crossing the specimen, a given amount of energy loss. A simple filtering device, comprising two 90° magnetic deflections separated by a reflection on an electrostatic mirror, makes possible to select a 1 eV energy bandwidth in the energy loss spectrum of 100 keV electrons without disturbing the quality of the image ; the chosen energy loss may go from zero (quasi-elastic images) up to several hundredths of electron-volts.
Ultrastructural Studies of the Lungs of Miniature Swine Following Cobalt Metal Inhalation
Authors: Watson John H.L. , Goodwin Jessica , Kerfoot Edward
Published: June 2020

Inhalation of dust by workers in the tungsten carbide industry causes pulmonary reactions, often referred to as “hard metal disease”. We have been interested in the ultrastructural changes in the lungs of such workers who have developed symptoms of interstitial pulmonary fibrosis. The symptoms are thought to be a function of metallic cobalt in the WC mixture. This animal inhalation study was undertaken to investigate this hypothesis, and experimental conditions simulating actual working conditions in the WC industry were used with groups of miniature swine which were exposed to Co atmospheres of 0·1 mg/m3 and 1·0 mg/m3.
Lung Ultrastructure of Exercising Monkeys After Nitrogen Dioxide Exposure
Authors: Bils Robert F.
Published: June 2020

Mice, rats, guinea pigs, rabbits and other common laboratory animals have been used in toxicology for many years. However, extrapolation of results to humans will always be under question. Although subhuman orimates have been utilized in many areas of research, little work has been done on the effects of toxic gases on the respiratory system of monkeys. Henry et al. bserved an emphysematous condition in monkey lungs exposed to 50 ppm NO2 for 2 hrs. while studying resistance to infection.

This is the beginning of a comprehensive project exposing exercising monkeys to atmospheric pollutants, and analyzing the morphological, biochemical and physiological changes that occur.
A New Method For Staining Epon-Araldite “Thick” Sections
Authors: Lloyd B. J. , Davis D. A.
Published: June 2020

In electron microscopy, the preparation and examination of "thick" sections is frequently of considerable value preliminary to final sectioning and staining. The use of the following simple method has been found to increase a number of histological details without the need to employ time-consuming supplemental stains.

A variety of tissues were prefixed for 1.5 hours in 0.05 M phosphate buffered acrcplein (0.6%) and purified glutaraldehyde (2.8%) at pH 7.5. Subsequently, postfixation was carried out in 0.05 M phosphate buffered osmium tetroxide for one hour at pH 7.5.
Quantitative Measurements on the Ion Etching of TMV
Authors: Bendet Irwin , Rizk Nabil
Published: June 2020

Preliminary results reported last year on the ion etching of tobacco mosaic virus indicated that the diameter of the virus decreased more rapidly at 10KV than at 5KV, perhaps reaching a constant value before disappearing completely.

In order to follow the effects of ion etching on TMV more quantitatively we have designed and built a second apparatus (Fig. 1), which incorporates monitoring devices for measuring ion current and vacuum as well as accelerating voltage. In addition, the beam diameter has been increased to approximately 1 cm., so that ten electron microscope grids can be exposed to the beam simultaneously.
The Ultrastructure of Mature and Mineralizing Cartilaginous Matrix in Deer Antler (Odocoileus Hemionus Hemionus)
Authors: Newbrey Jarrett W. , Banks William J.
Published: June 2020

Core biopsies of mature and mineralized cartilage were removed from the main beams and tines of deer antler at various times throughout the growing season and were examined with an electron microscope (Hitachi, HS-8; Zeiss, EM-9A). Certain morphological characteristics were identical with those features reported for matrices of mature and mineralizing somatic cartilage .

The lacunae (L) of the mature cartilage cells were not devoid of matrix components. Although the lacunae lacked any banded collagen fibers (Fig. 1), they did contain many interconnected fibrils (F) which were associated with lead-stained granules (arrows). The lead binding coincided with matrix granules described in the lacunae and general matrix of growth plate cartilage.
Functional Acinar Cell Carcinoma of the Pancreas
Authors: Burns W. A. , Vander Weide G. C. , Matthews M. J.
Published: June 2020

Malignant tumors arising from pancreatic acinar cells are relatively uncommon. Rarely these tumors may be functional, secrete amylase or lipase and present clinically with polyarthropathies and skin lesions resembling erythema nodosum. Some of the reported cases were supported with confirmative data, but none to our knowledge had chemical and ultrastructural confirmation. We wish to report the electron microscopic and bio-chemical studies of a functional acinar cell carcinoma of the pancreas.

The patient was a 52 year old, black male who had constant complaints of polyarthropathy and was found to have a tumor of the pancreas with liver metastases.

Tissue from a pre-mortem liver biopsy and post-mortem from the pancreatic tumor and the liver metastases were examined.
Altered Fine Structure of B Lymphocytes Correlated with Defective Terminal Differentiation
Authors: Bockman Dale E. , Frank Wu L. Y. , Lawton Alexander R. , Cooper Max D.
Published: June 2020

B-lymphocytes normally synthesize small amounts of immunoglobulin, some of which is incorporated into the cell membrane where it serves as receptor of antigen. These cells, on contact with specific antigen, proliferate and differentiate to plasma cells which synthesize and secrete large quantities of immunoglobulin. The two stages of differentiation of this cell line (generation of B-lymphocytes and antigen-driven maturation to plasma cells) are clearly separable during ontogeny and in some immune deficiency diseases. The present report describes morphologic aberrations of B-lymphocytes in two diseases in which second stage differentiation is defective.
The Disappearance of the Acid Mucopolysaccharide Coating in Blood Vessels Exposed to Oxygen, Radiation and in Old Age and Possible Implications
Authors: Philpott Delbert E. , Takahashi Akira , Turnbill Charles
Published: June 2020

The blood vessels are known to be involved in radiation pathology, both the fragility and permeability being altered. Delayed radiation response has been shown to involve a loss of the blood supply to necrotic areas. Since the structure of the mucopolysaccharide (MPS) coating on the luminal wall is heparin-like in nature and heparin has known anti-coagulant properties, the observed increase in clotting in older persons suggests possible alteration of the acid MPS coating.

Rats were treated in several ways to examine the effect of various factors on the MPS coating. Young rats were whole-body irradiated with 2400r X-rays and sacrificed 24 and 48 hours later. Another group of rats were exposed to 100% oxygen at one atmosphere for periods up to 72 hours.
The Cold Stub: A Simple Stage For the Direct Observation of Frozen Samples in the Scanning Electron Microscope
Authors: McAlear James H. , Germinario Louis T.
Published: June 2020

Cold block devices have been used in the scanning electron microscope to permit the viewing of frozen samples. These have the advantage of simplicity in that feedthroughs for liquid nitrogen (LN) or temperature control may not be necessary. Previous cold stages for the SEM have either been cumbersome and expensive or in some way restrict the use of the microscope for general purposes. Previous cold sinks designed by the authors, like other common cold stages, require a period of temperature adjustment so that contamination introduced to the sample surface during the loading phase of the SEM sublimes, exposing the underlying frozen surface. The present device carries the simplification steps somewhat further.
A New Working Hypothesis for the Structure and Function of the Golgi Apparatus in Plant Cell Wall Biogenesis
Authors: Malcolm Brown R.
Published: June 2020

It is the general belief of many investigators that the pathway of cellulose biogenesis occurs via soluble pools of hexose phosphate monomers and the plasma membrane which is thought to be the site of polymerization and/or crystalization. Brown and coworkers and Ray (see 1) have proposed to the contrary that the Golgi apparatus is the site of cellulose biogenesis in certain scale-producing algae and higher plants respectively. While it has been fairly well established that cellulose can be biosynthesized by the Golgi apparatus, considerable doubt has been expressed that this type of system could be applicable to cellulose biogenesis in higher plant systems. Conversely, the problems associated with in vitro cellulose biosynthesis in Golgi-enriched homogenates raises questions about the in vivo localization of B-(1,4)-glucan synthetase activity.
Preservation of Plant Cell Surfaces For Scanning Electron Microscopy
Authors: Sicko Linda M. , Jensen Thomas E.
Published: June 2020

The use of critical point drying is rapidly becoming a popular method of preparing biological samples for scanning electron microscopy. The procedure is rapid, and produces consistent results with a variety of samples. The preservation of surface details is much greater than that of air drying, and the procedure is less complicated than that of freeze drying. This paper will present results comparing conventional air-drying of plant specimens to critical point drying, both of fixed and unfixed material. The preservation of delicate structures which are easily damaged in processing and the use of filter paper as a vehicle for drying will be discussed.
Scanning Electron Microscopy of Plant Surfaces - Applications
Authors: Dayanandan P. , Kaufman P. B.
Published: June 2020

Previous studies and our own observations of surface features in more than 80 species show that the SEM can be of great value in determining the nature and distribution of stomata, trichomes, wax, cuticular ridges, silica bodies, spores and other particulate pollutants as well as meristems and their derivatives. We suggest applications of surface studies to the fields of taxonomy and plant water relations.

Many epidermal surfaces can be observed with or without coating at 15 KeV with no detectable alterations in the wax pattern. Wax is deposited as granular, rod-like, thread-like or plate-like structures. Of particular interest are the wax patterns around stomatal apparatuses.
Fine Structure of Posthodiplostomum Minimum Metacercarial Cyst Wall
Authors: Mitchell C. W.
Published: June 2020

The metacercaria of the digenetic trematode Posthodiplostomum minimum inhabit the major visceral organs, e.g. liver, kidney or heart, of numerous species of fresh-water fish as second intermediate hosts. These larval trematodes establish a thin cyst wall which is composed of a cellular, outer wall of host origin and an inner, acellular layer of parasitic origin. This report describes some preliminary observations on the ultrastructural organization of the metacercarial cyst wall found within naturally infected sunfish liver.

These observations represent the first strigeid cyst studied by electron microscopy. However, cyst structure resembled others encysted within tissues of an intermediate host. A primary wall, apparently secreted by the parasite, prevents host destruction of the metacercaria.
Action of the Glandular Vas Deferens in the Nematode Ascaris Lumbricoides
Authors: Foor W. Eugene
Published: June 2020

It has been well demonstrated that the spermatozoa of certain nematodes undergo marked morphological and physiological changes after they have been deposited in the reproductive tract of the female worm. Although it was previously assumed that the spermatozoan changes occur in response to stimulatory substances present within the female tract, recent investigations utilizing Ascaris lumbricoides as the experimental model, provide strong evidence that the substances responsible for the spermatozoan changes actually originate in the glandular vas deferens of the male worm.

In Ascaris the glandular vas deferens is a whitish gland located posterior to the seminal vesicle. The cells comprising the gland are characterized by the presence of large amounts of rough endoplasmic reticulum and Golgi saccules which apparently give rise to substances which are secreted into adjacent collecting ducts (figure 3) and eventually find their way to the lumen.
Fine Structure of the Anthocodium of Renilla Mulleri
Authors: Spurlock Ben O.
Published: June 2020

Renilla mulleri is a colonial marine coelenterate commonly called a sea pansy. Its body consists of a distal reniform shaped rachis bearing numerous secondary polyps which are restricted to the superior surface and a single proximal peduncle devoid of polyps. The secondary polyps illustrate the dimorphic nature of the colony by establishing a division of labor among zooids for feeding and circulation. The latter is accomplished by numerous clusters of tentacle-less zooids, which serve as pumps driving water into the colony, called siphonozooids. Water passes from the colony through a single exhalant siphonozooid. The feeding and/or reproductive polyps are called autozooids. These polyps are typically alcyonarian in that they possess eight hollow pinnate tentacles with eight single complete mesenteries. All polyps are embedded in a common tissue mass, the coenenchyme. The anthocodium, the only portion of the autozooid which projects above the coenenchyme, is the subject of this paper.
Fractographic Studies of the Honey Bee Pore Plate Organ by Scanning Electron Microscopy
Authors: Dietz Alfred , Anderson Leroy M.
Published: June 2020

Odor perception in honey bees is confined to the eight distal segments of the 10 segmented antennal flagellum. Electrophysiological studies have demonstrated that two types of olfactory cells, associated with the pore plates on the antennae of all castes of honey bees, respond to the pheromones of the honey bee. One of the cell types is specific for the queen substance, while the other responds to the odor of the Nasonov gland. Work in our laboratory on the surface structure of this sensory organ has shown that there are considerable variations in the shape of the pore plate. Whether such structural differences between these pore plates could have any biological significance in terms of olfaction cannot be stated at present. However, a detailed knowledge of the fine structure of olfactory sensilla is necessary for a critical evaluation of the olfactory function.
Histamine Storage and Release
Authors: Uvnäs B.
Published: June 2020

Isolated rat peritoneal mast cells respond to compound 48/80 and to antigen with degranulation and histamine (Hi) release. In electronmicroscopic studies the initial structural changes were seen at the periphery of the cell immediately adjacent to the cell membrane, indicating that the effect of compound 48/80 (and of antigen) starts from the cell membrane. Close apposition and fusion of the cell membrane and the perigranular membrane occurs. The fusion process proceeds towards the cell interior by additional fusions so that branching cavities are formed. The granules in these cavities swell, become less electron dense and lose their surrounding membrane. Some of the granules are extruded to the exterior of the cells, whilst others are retained in the cavities.
Reversible Effects of Hyperosmolar Sucrose on Frog Sympathetic Ganglion
Authors: Minker E. , Riker W. K. , Russell N. J.
Published: June 2020

Saline solutions made hyperosmotic by addition of sucrose increase the discharge frequency of miniature spontaneous junctional potentials at neuromuscular junctions and sympathetic ganglia and can alter structure in both muscle and nerve. Since effects of such solutions on synaptic structure are unknown, we have investigated the influence of hyperosmolarity on function and ultrastructure in synaptic regions of isolated abdominal sympathetic ganglia of the bullfrog, Rana catesbiana.

Synaptic transmission was monitored by extracellular recording of postganglionic responses to supramaximal.preganglionic stimulation (0.3 Hz). Ganglia were first equilibrated in normal frog Ringer's solution, then transferred to test solutions, and some ganglia were subsequently returned to normal Ringer's to examine functional and structural recovery.
Electron Microscopy of Virus in L1210V Cells
Authors: Chen Pearl L. , Sarkar Nurul H. , Moore Dan H.
Published: June 2020

Two cell culture lines established in vitro, L1210VA and L1210VB, were obtained from Dr. Dorris J. Hutchison, Sloan- Kettering Cancer Research Institute, Rye, N. Y. They were maintained in Earl'-Eagle' medium containing a double dose of glutamine.

The original lymphatic leukemia L1210 was induced by Law et al in a DBA/2 female mouse. In these cells grown intraperitoneally in DBA mice the presence of intracytoplasmic A particles and their incorporation into budding virions, as well as extracellular particles with the morphology of leukemiasarcoma viruses have been described. Since the intracytoplasmic A particles are related to the development of B particles it was our interest to investigate whether or not the cells produce B particles.
Homologs of Leydig and Sertoli Cells in the Testis of the Teleost, Oryzias Latipes
Authors: Gresik Edward W.
Published: June 2020

The testis of O. latipes is composed of cysts containing germinal elements Tn various stages of spermatogenesis (Fig. 1). The simple epithelial cells of the cyst wall are the Sertoli cell (SC) homologs. When the contained germinal elements have matured, the cyst epithelium fuses with that of the terminal divisions of the efferent duct system. In the connective tissue stroma surrounding the cysts and ducts, the Leydig cell (LC) homologs are found.

The LC (Fig. 2) contains a central vesicular nucleus with a distinct nucleolus. Flattened cisternae of rough ER are distributed throughout the cytoplasm; smooth ER, usual in steroidogenic cells, is not present.
Ultrastructure of the Mongolian Gerbil Spermatozoa
Authors: Majumdar S. K. , Thomas T. S.
Published: June 2020

With the recent broadening of the study of fertilization in vitro and in vivo, the importance of spermatozoon ultrastructure has been greatly emphasized. A great deal of research has been conducted with mammalian spermatozoa. However, no information is available on the Mongolian gerbil (Meriones unguiculatus). Small blocks of testis and epididymis of mature males were fixed in 4% glutaraldehyde and post-fixed in 1% osmium tetroxide adiusted to pH 7.2 with 0.1 M sodium cacodylate. After dehydration, the tissues were embedded in Epon. Sections were cut with glass knives on a Porter-Blum ultramicrotome stained with uranyl acetate-lead-citrate, and examined with an RCA EMU-3G electron microscope.

The head of the Mongolian gerbil is falciform and contains a nucleus, an acrosome, and membranous envelopes (Figs. 1 & 7).
Necessity of Endogenous Cholesterol for Normal Myelination in Central and Peripheral Nervous System
Authors: Rawlins Frank A.
Published: June 2020

The results of several recent investigations on the role of cholesterol in myelin, appear to indicate that the synthesis and maintenance of myelin is achieved by at least three processes: a) recycling of molecules within the nervous system; b) synthesis of new molecules, and c) incorporation of exogenous material. Although synthesis of cholesterol, which is very high during rapid myelination, deereases to very low levels in the adult animal, uptake of exogenous cholesterol by myelin occurs not only during myelination but also in the adult animal.Whether exogenous and endogenous cholesterol molecules accomplish different roles in the development of the nervous system in general and in the formation and maintenance of the myelin sheaths in particular is still unknown.
A Study on the Fine Structure of the Lateral Line Organ of the Sea Eel
Authors: Hama K.
Published: June 2020

The lateral line organs of the sea eel consist of canal and pit organs which are different in function. The former is a low frequency vibration detector whereas the latter functions as an ion receptor as well as a mechano receptor.

The fine structure of the sensory epithelia of both organs were studied by means of ordinary transmission electron microscope, high voltage electron microscope and of surface scanning electron microscope.

The sensory cells of the canal organ are polarized in front-caudal direction and those of the pit organ are polarized in dorso-ventral direction. The sensory epithelia of both organs have thinner surface coats compared to the surrounding ordinary epithelial cells, which have very thick fuzzy coatings on the apical surface.
An Ultrastructural Study of the Lateral Vestibular Nucleus in the Rat: Changes in Glial Cells Following Partial Deafferentation
Authors: Johnson J. E.
Published: June 2020

Mori and Leblond have reported that oligodendrocytes in the corpus callosum of rats may be classified into three types consisting of light, medium and dark. The light oligodendrocytes are the largest, and the dark ones are the smallest. In the present study, oligodendrocytes of different sizes and densities were found to occur in the normal lateral vestibular nucleus of the rat. Here, as reported in the corpus callosum, the darkest cells are the smallest. The largest of the oligodendrocytes in the lateral vestibular nucleus have a density which approaches that of astrocytes, which are also present throughout the nucleus.

The lateral vestibular nuclei of 18 rats were partially deaffer-entated by aspirating the anterior vermis of the cerebellum, from which the nucleus receives input.
Ultrastructural Aspects of Golgi Complex Function in Parathyroid Cells of Winter Frogs
Authors: Dougherty William J.
Published: June 2020

The regulation of secretion in exocrine and endocrine cells has long been of interest. Electron microscopic and other studies have demonstrated that secretory proteins synthesized on ribosomes are transported by the rough ER to the Golgi complex where they are concentrated into secretory granules. During active secretion, secretory granules fuse with the cell membrane, liberating and discharging their contents into the perivascular spaces. When secretory activity is suppressed in anterior pituitary cells, undischarged secretory granules may be degraded by lysosomes. In the parathyroid gland, evidence indicates that the level of blood Ca ions regulates both the production and release of parathormone. Thus, when serum Ca is low, synthesis and release of parathormone are both stimulated; when serum Ca is elevated, these processes are inhibited.
Combined elemental and structural imaging in a computer contrlled analytical electron microscope
Authors: Leapman R. D. , Fiori C. E. , Gorlen K. E. , Gibson C. C. , Swyt C. R.
Published: June 2020

The modern analytical electron microscope incorporates a scanning transmission (STEM) capability together with a variety of detectors for signals resulting from the interaction of the electron probe with the sample. Information about both the elemental composition and morphology of the sample is available. The images derived from STEM signals can be readily digitized, thus allowing precise numerical processing of the data. Since several signals may be recorded concurrently one pixel at at time, the corresponding images are in registration and may be overlaid for comparison or combined for example to give the ratio of two elements. Such composite images can be expected to provide more information than each separately.

The large amount of data which has to be processed in the acquisition of a digitized image requires a considerable amount of computer hardware and software. The system developed at NIH for application in biology has been described by Gorlen et al. and Fiori et al. and is outlined in Fig. 1. A Digital Equipment Corporation PDP 11/60 computer with an LSI 11/23 satellite computer is interfaced to a Hitachi H700H TEM-STEM with a magnetic sector electron energy loss spectrometer (EELS), one Kevex top-looking energy dispersive x-ray detector and one Tracor Northern side-looking detector; these provide the analytical signals with digital output.
Hot stage study of γ →α Al2O3 transformations
Authors: Tucker Dennis , Kenik E. A. , Hren John
Published: June 2020

It has been observed in spherical A12O3 particles precipitated from sulfate solution that polycrystalline γ-Al2O3 forms at 900°C in air during calcination. Further heating brings about the transformation to single crystal α-Al2O3 particles at approximately 1100°C. This behavior has also been observed by other authors for the γ→α Al2O3 transformation. In order to determine the nucleation sites and trie general growth characteristics of these 1-10 μm diameter particles, it was decided to study the transformation in situ in a HVEM*.

Powders were prepared after the method of Onoda and Curreri and placed on tungsten grids with a thin Pt film substrate. The powders were then heated in situ in a 1 meV microscope* equipped with a single tilt hot stage capable of achieving 1250°C and a residual gas analyzer.
Atomic structure of ion-implantation produced amorphous silicon and amorphous-crystalline interface structure and kinetics
Authors: Narayan J. , Fathy D.
Published: June 2020

The structure of amorphous silicon determines its physical properties ranging from crystallization kinetics to efficiency of solar cells. One point of particular interest has been the existance of microcrystallites in the amorphous phase. Different crystallization kinetics are obtained for purely amorphous silicon and for amorphous silicon having a trace of crystallinity. The incorporation of dopants into substitutional sites after solid-phase crystallization has been also found to be affected by the degree of amorphousness.

The purpose of this investigation was two fold: first, to characterize the structure of amorphous silicon, and second to study the structure of amorphous-crystalline interface. The importance of these two factors in the crystallization phenomena is discussed.
Cathodoluminescence microanalysis of semiconductors: Potential and limits
Authors: Löhnert K. , Kubalek E.
Published: June 2020

The potential of the cathodoluminescence (CL) technique in the SEM or STEM for the investigation of semiconducting materials and devices is based on the fact, that it enables the evaluation of inhomogeneities in electronic material properties on a micron scale. Full use of this potential can be only made, however, if the experimental setup is useful not only for the measurement of the integral (undispersed) CL but also for spectral, temporal and temperature-dependent analysis. These requirements are not met with commercial electron beam instruments and therefore suited equipment has to be provided and assembled by the user (for detailed information on the most advanced experimental arrangements see /1,2/).

The three primary quantities then available for analysis are a) the CL intensity, b) the CL spectrum and c) the CL decay after pulse excitation, which will be dealt with in the same sequence.
Etch characteristics and defect structure in sputtered zinc oxide films
Authors: Hickernell F.S. , Hickernell T.S.
Published: June 2020

Sputtered zinc oxide films are used in the fabrication of acoustical and optical microelectronic devices. The ZnO deposits as a fine grain C-axis oriented polycrystalline film on amorphous substrates with piezoelectric and electro-optic properties approaching single crystal material. Different sputtering techniques have yielded different levels of performance particularly with respect to surface acoustic wave, SAW, and guided optical wave, GOW, propagation characteristics. Etching studies have shown that rapid etch rates are associated with lower velocities and higher propagation losses whereas slow etch rates yield films with near single crystal velocities and low propagation losses. In this investigation partially etched ZnO films were examined using a scanning electron microscope to determine the microstructural changes. This has led to a more detailed understanding of the defect structure of the films, the nature of the etch process and its relation to the etch characteristics of single crystal ZnO.
Practical application of type I magnetic contrast in the SEM: The delineation of defects in magnetic recording disks
Authors: Smallen M.J. , Mee P.B.
Published: June 2020

To locate specific surface and/or subsurface defects on a magnetic recording disk so called "write bracketing" can be employed in which regions of alternating magnetization are written circumferentially from the defect. Visualization and hence delineation of the defect in question can be realized through the use of Bitter colloid decoration of the flux transitions. However, to carry out EDX and surface analysis on these defects, unadulterated surfaces are normally required. To achieve both flux transition visualization and analysis, a modified Banbury Nixon detector was constructed to image the write bracketing via Type I magnetic contrast in the SEM. The Type I magnetic contrast technique has been reviewed by Wells and, essentially, involves, in the case of uniaxial anisotropic materials, the deflection by the Lorentz force of the lowest energy secondary electrons as they traverse the write bracket fringing field. To date, applications of Type I magnetic contrast have been restricted to domain imaging in cobalt, bubble materials and magnetic tapes, in a purely demonstrative fashion with no ultization as a failure analysis tool having been reported. This paper describes the use of magnetic contrast to locate defects for analysis on longitudinal γFe2O3 particulate recording media.
High-resolution structure determination by ALCHEMI
Authors: Self Peter G. , Buseck Peter R.
Published: June 2020

ALCHEMI (Atom Location by CHanneling Enhanced Microanalysis) enables the site occupancy of atoms in single crystals to be determined. In this article the fundamentals of the method for both EDS and EELS will be discussed. Unlike HRTEM, ALCHEMI does not place stringent resolution requirements on the microscope and, because EDS clearly distinguishes between elements of similar atomic number, it can offer some advantages over HRTEM. It does however, place certain constraints on the crystal. These constraints are: a) the sites of interest must lie on alternate crystallographic planes, b) the projected charge density on the alternate planes must be significantly different, and c) there must be at least one atomic species that lies solely on one of the planes.

An electron beam incident on a crystal undergoes elastic scattering; in reciprocal space this is seen as a diffraction pattern and in real space this is a modulation of the electron current across the unit cell. When diffraction is strong (i.e., when the crystal is oriented near to the Bragg angle of a low-order reflection) the electron current at one point in the unit cell will differ significantly from that at another point.
An AEM study of phosphorus segregation in a stainless steel
Authors: Pelton A. R. , Westmacott K. H.
Published: June 2020

The deleterious effects on the mechanical properties of phosphorus segregation to grain boundaries in ferritic alloys are well documented in the metallurgical literature. An understanding of this recurring problem has profited from the recent application of analytical electron microscopy (AEM). EDS analysis has allowed the detection of phosphorus in thin films at prior austenite grain boundaries and in association with intergranular carbides. Although austenitic alloys also suffer from property degradation due to segregated impurity elements, comparable studies have not been conducted on these materials. The purpose of this paper, therefore, is to report the results from an AEM investigation of phosphorus segregation in an austenitic stainless steel. Of particular concern is the effect of grain boundary type on phosphorus segregation and precipitation.

An Fe-18 Cr-10 Ni-0.3P (weight percent) steel was quenched from 1150°C and aged between 400-700°C. Samples were prepared by standard polishing techniques; those samples analyzed by EDS were lightly ion-beam milled to remove surface films formed by the electropolishing.
NiAl precipitation in Fe-12w/o Cr-5w/o Ni-4w/o Al
Authors: Murr L.E. , Dunning J.S. , Shankar S.
Published: June 2020

Aluminum additions to conventional 18Cr-8Ni austenitic stainless steel compositions impart excellent resistance to high sulfur environments. However, problems are typically encountered with aluminum additions above about 1% due to embrittlement caused by aluminum in solid solution and the precipitation of NiAl. Consequently, little use has been made of aluminum alloy additions to stainless steels for use in sulfur or H2S environments in the chemical industry, energy conversion or generation, and mineral processing, for example.

A research program at the Albany Research Center has concentrated on the development of a wrought alloy composition with as low a chromium content as possible, with the idea of developing a low-chromium substitute for 310 stainless steel (25Cr-20Ni) which is often used in high-sulfur environments. On the basis of workability and microstructural studies involving optical metallography on 100g button ingots soaked at 700°C and air-cooled, a low-alloy composition Fe-12Cr-5Ni-4Al (in wt %) was selected for scale up and property evaluation.
The oxidation of Inconel alloy MA754 at low oxidation potential
Authors: Braski D. N. , Goodell P. D. , Cathcart J. V. , Kane R. H.
Published: June 2020

It has been known for some time that the addition of small oxide particles to an 80 Ni—20 Cr alloy not only increases its elevated-temperature strength, but also markedly improves its resistance to oxidation. The mechanism by which the oxide dispersoid enhances the oxidation resistance is being studied collaboratively by ORNL and INCO Alloy Products Company.

Initial experiments were performed using INCONEL alloy MA754, which is nominally: 78 Ni, 20 Cr, 0.05 C, 0.3 Al, 0.5 Ti, 1.0 Fe, and 0.6 Y2O3 (wt %).Small disks (3 mm diam × 0.38 mm thick) were cut from MA754 plate stock and prepared with two different surface conditions. The first was prepared by mechanically polishing one side of a disk through 0.5 μm diamond on a syntron polisher while the second used an additional sulfuric acid-methanol electropolishing treatment to remove the cold-worked surface layer. Disks having both surface treatments were oxidized in a radiantly heated furnace for 30 s at 1000°C. Three different environments were investigated: hydrogen with nominal dew points of 0°C, —25°C, and —55°C. The oxide particles and films were examined in TEM by using extraction replicas (carbon) and by backpolishing to the oxide/metal interface. The particles were analyzed by EDS and SAD.
Chemical partitioning of elements in Ni-base MC-carbide reinforced eutetic superalloys
Authors: Koch E. F. , Hall E. L. , Yang S. W.
Published: June 2020

The plane-front solidified eutectic alloys consisting of aligned tantalum monocarbide fibers in a nickel alloy matrix are currently under consideration for future aircraft and gas turbine blades. The MC fibers provide exceptional strength at high temperatures. In these alloys, the Ni matrix is strengthened by the precipitation of the coherent γ' phase (ordered L12 structure, nominally Ni3Al). The mechanical strength of these materials can be sensitively affected by overall alloy composition, and these strength variations can be due to several factors, including changes in solid solution strength of the γ matrix, changes in they γ' size or morphology, changes in the γ-γ' lattice mismatch or interfacial energy, or changes in the MC morphology, volume fraction, thermal stability, and stoichiometry. In order to differentiate between these various mechanisms, it is necessary to determine the partitioning of elemental additions between the γ,γ', and MC phases. This paper describes the results of such a study using energy dispersive X-ray spectroscopy in the analytical electron microscope.
Lorentz electron microscopy of rare-earth permanent magnets
Authors: Hadjipanayis G. C. , Horton L. L.
Published: June 2020

Rare-earth-cobalt permanent magnets are characterized by large coercive fields and energy products. The hard magnetic properties depend strongly on the microstructure and are usually achieved after a complex heat treatment. A single phase microstructure with low defect density has been observed in SmCo5 and Sm2Co17 magnets. The addition of copper to these materials produces a two-phase cellular structure with a 1:5 hexagonal phase at the cell boundaries and a 2:17 rhombohedral phase in the cell interiors. The single- and two-phase microstructures lead to different magnetic hysteresis behavior. The purpose of this work is to determine the relationship of the microstructure with the magnetic domain structure to further clarify the origin of the high-coercive fields in these permanent magnet materials. Lorentz electron microscopy has been used to image the domain walls and study their interactions with crystalline defects. A JEM 120C TEM equipped with an AMG objective pole piece has been used for these studies. The magnetic field at the specimen is 3.4 Oe with this pole piece.