bluuebunny/crossref_metadata_2025_split huggingface dataset:
Lattice Imaging Analysis of the Solid State β-α Ot Transformation in CVD Grown SiC
Authors: Shinozaki S. , Kinsman K. R. 
Published: June 2020

In SiC anisotropic α phase morphologies and planar defect dominated microstructures of the close-packed α (Hexagonal) and β (FCC) phases, and their coherent crystallographic relationship to one another in mixtures, have been observed. These characteristics indicate a fundamental mechanistic similarity to other FCC-HCP solid state transformations in a host of metallic alloy systems. In these metallic systems (1,2) as well as in SiC (3), it is apparent that the key transformation feature is rearrangement of close packed planes by nucleation and propagation of stacking faults. In this paper, we present support for this view, using chemical vapor deposited (CVD) SiC as a basis material.The deposition condition used encourages large grains, a textured arrangement of the grains, and promotes profuse twinning along {111} β aligned mostly along the direction of growth (Fig. 1). X-ray diffraction analysis indicates the bulk sample is β phase. Transmission electron microscopy and selected area electron diffraction (SAD) of a single grain (Fig. 2) reaffirm that the as-grown structure is comprised of β phase with twins and stacking faults.
Specialized Junctions of the Intercalated Disc of the Active and Hibernating Bat Heart
Authors: Hagopian Martin 
Published: June 2020

Active bats, Myotis lucifugus, were caught in October, and hibernating bats were caught in January from their natural habitat. Left ventricles were fixed in 6.25% cacodylate buffered gluturaldehyde, washed in buffer, and postfixed in 1% osmium tetroxide. Some tissue in each group was stained en bloc with uranyl acetate, dehydrated, and embedded in Araldite or Epon.The muscle cells of the bat heart are approximately cylindrical in shape and are connected with one another end-to-end at the intercalated discs. Occasionally the cardiocytes are connected along the lateral surfaces. In general the intercalated disc is composed of transverse and longitudinal segments.
Unique Photoreceptor in Tornaria Larvae (Hemichordata: Enteropneusta)
Authors: Woollacott Robert M. , Brandenburger Jean L. , Eakin Richard M. 
Published: June 2020

To extend a survey of photoreceptors in the animal kingdom, initiated by one of us (RME), we examined electron microscopically the paired eyespots on tornariae of two species of hemichordates. Some specimens (species unknown) were collected from the plankton near the Santa Catalina Marine Biological Laboratory, Santa Catalina Island, California; other tornariae were reared from eggs of Ptychodera flava at the University of Hawaii.The tornarian ocellus studied by us is a single-layered, ectodermal cup open to the exterior but without a lens, contrary to the description of light microscopists (see 1). Two types of cells form the wall of the eyecup: sensory and pigmented.
Ultrastructural Findings of a Rare Myxoid Tumor in a Case of Scleroderma
Authors: Cowley L. H. , Turk L. L. , Grafton W. D. , Jamison R. M. 
Published: June 2020

Scleroderma is a skin disease of unknown cause. The systemic form frequently begins peripherally, producing atrophy of the underlying fat and a thickening of the dermis. Tumors associated with scleroderma are distinctly uncommon. Only one other similar case has been alluded to in the literature.This patient presented with tumors 4mm to 3cm in size over the fingers and toes. The tumors were tense to touch although readily depressable without pain. A large tumor was removed surgically from the right index finger. Hematoxylin and eosin staining of paraffin sections revealed a normal appearing epidermis with slight thickening of the papillary dermis. The reticular dermis was edematous and contained sparse amounts of collagen with some fibroblast-like cells which were spindle-shaped and stellate. Histochemical stains showed a large quantity of amorphous material that was PAS positive, diastase-resistant and alcian blue positive at pH 4.
Spermatogenesis in the Dragonfly with Particular Reference to the Cytoplasmic Organelles
Authors: Sekhon Sant S. 
Published: June 2020

Although there have been numerous studies concerning the morphogenetic changes accompanying the maturation of insect sperm, only a few deal with the sperm differentiation in the dragonflies. In two recent electron microscopic studies Kessel, has comprehensively treated the erlationship of microtubules to the nucleus and mid-piece structures during spermiogenesis in the dragonfly. The purpose of this study is to follow the sequential nuclear and cytoplasmic changes which accompany the differentiation of spermatogonium into a mature sperm during spermatogenesis in the dragonfly (Aeschna sp.).The dragonfly spermatogonia are characterized by large round nuclei. Loosely organized chromatin is usually unevenly distributed within the spermatogonial nuclei. The scant cytoplasm surrounding the nucleus contains mitochondria, the Golgi apparatus, elements of endoplasmic reticulum and numerous ribosomes (Fig. 1).
Binucleate Spermiogenesis in the Mouse
Authors: Wolosewick John J. 
Published: June 2020

Classically, the male germinal epithelium is depicted as synchronously developing uninucleate spermatids conjoined by intercellular bridges. Recently, binucleate and multinucleate spermatids from human and mouse testis have been reported. The present paper describes certain developmental events in one type of binucleate spermatid in the seminiferous epithelium of the mouse.Testes of adult mice (ABP Jax) were removed from the animals after cervical dislocation and placed into 2.5% glutaraldehyde/Millonig's phosphate buffer (pH 7.2). Testicular capsules were gently split and separated, exposing the tubules. After 15 minutes the tissue was carefully cut into cubes (approx. 1mm), fixed for an additional 45 minutes and processed for electron microscopy.
Structures Resembling Striated Rootlets in Oocytes
Authors: Ernst Valerie V. 
Published: June 2020

During the earliest stage of oocyte development in the limpet, Acmea scutum, Golgi complexes are small, few and randomly dispersed in the cytoplasm. As growth proceeds, the Golgi complexes increase in size and number and migrate to the periphery of the cell. At this time, fibrous structures resembling striated rootlets occur associated with the Golgi complexes. Only one fibrous structure appears to be associated with a Golgi complex.The fibers are periodically cross banded with an average of 4 dense fibrils and 6 lighter fibrils per period (Fig. 1). The cross fibrils have a center to center spacing of about 7 run which appears to be the same as that of the striated rootlets of the gill cilia in this animal.
Effects of Chorionic Gonadotropic Hormone (HCG) on the Ultrastructure of Normal and Grafted Ovaries
Authors: Baccarini I. M. 
Published: June 2020

Human chorionic gonadotrophic hormone (HCG) has a luteotropic effect which induces luteinization of the granulosa cells. A large concentration of HCG in a culture of granulosa cells induces luteinization and increases the levels of progesterone secreted by each of the granulosa cells. The present report describes the submicroscopic structure of the granulosalutein cells under long term daily doses of human chorionic gonadotropic hormone.The ovaries from a group of 10 mice 30 days old were removed, and a small piece of one ovary was placed into the spleen. Another group of 5 mice of the same age was used for a control. Human chorionic gonadotropic hormone (28 Ul) was injected daily subcutaneously. The vagina was opened on the fourth day after the first injection.
Mass and Mass Loss Measurements on DNA and fd Phage
Authors: Wall Joseph 
Published: June 2020

Mass measurements can be done with the scanning transmission electron microscope in a manner similar to the densitometry of conventional microscope plates. Since the measurements are made directly on the microscope output signal, however, there are none of the non-linearities associated with film. The two signals (proportional to normalized elastically and inelastically scattered currents) are recorded directly on digital tape for analysis.Mass can be determined from the scattering data using atomic scattering cross-sections and assuming the cross-section of an object is the sum of the individual atomic cross-sections. Since the elastic and inelastic cross-sections have different dependence on atomic number, it also is possible to estimate the average Z of the object being measured. These calculations are performed using a Nova 800 computer system which is interfaced directly to the microscope.
Head Size and DNA Content in Bacteriophage T4
Authors: Eiserling Fred , Doermann A. H. , Boehner Linde 
Published: June 2020

The control of form or shape inheritance can be approached by studying the morphogenesis of bacterial viruses. Shape variants of bacteriophage T4 with altered protein shell (capsid) size and nucleic acid (DNA) content have been found by electron microscopy, and a mutant (E920g in gene 66) controlling head size has been described. This mutant produces short-headed particles which contain 2/3 the normal DNA content and which are non-viable when only one particle infects a cell (Fig. 1).We report here the isolation of a new mutant (191c) which also appears to be in gene 66 but at a site distinct from E920g. The most striking phenotype of the mutant is the production of about 10% of the phage yield as “giant” virus particles, from 3 to 8 times longer than normal phage (Fig. 2).
Stereo Electron Microscopy and Problems of Interpretation
Authors: Steere Russell L. 
Published: June 2020

The need for and value of a goniometer stage and stereo electron microscopy to obtain maximum information from preshadowed carbon replicas of frozen biological specimens has already been documented. Now it is important that one be forewarned of the possibility of misinterpretation of the morphology of an object if only a single electron micrograph or a single stereo pair is used for interpretation.Surface replicas of the outer surface of frozen begonia petals were prepared in the usual manner. The large pieces of cleaned replica were lifted onto uncoated 75 mesh grids and examined in the JEM 100-B electron microscope with goniometer stage.
Silicon Tetrachloride Synthesis from Rice Hulls: Transmission and Scanning Electron Microscope Study
Authors: Thomas Richard S. , Basu Prabir K. , Jones Francis T. 
Published: June 2020

Silicon tetrachloride, used in industry for the production of highest purity silicon and silica, is customarily manufactured from silica-sand and charcoal.SiCl4 can also be made from rice hulls, which contain up to 20 percent silica and only traces of other mineral matter. Hulls, after carbonization, actually prove superior as a starting material since they react at lower temperature. This use of rice hulls may offer a new, profitable solution for a rice mill byproduct disposal problem.In studies of the reaction kinetics with carbonized hulls, conversion of SiO2 to SiCl4 was found to proceed within a few minutes to a constant, limited yield which depended reproducibly on the ambient temperature of the reactor. See Fig. 1. This suggested that physical or chemical heterogeneity of the silica in the hull structure might be involved.
Cytopathology of Coxsackievirus B3 Infection in Newborn Mouse Pancreas
Authors: Harrison Alyne K. , Bauer Sally P. , Murphy Frederick A. 
Published: June 2020

Of the infectious agents suspected of causing acute pancreatitis in man, the group B Coxsackieviruses have long been regarded the prime candidates. Histopathological studies of these viruses in mice have shown extensive damage to acinar cells while ducts and islets were spared. However, recent evidence Indicates that particular Coxsackievirus B types may affect acinar cells whereas others may attack endocrine cells. In the present study, Coxsackievirus B3 was used to elicit a necrotizing pancreatitis in newborn mice which involved both the endocrine and exocrine portions of the gland.Litters of Swiss mice (ICR strain), less than 12 hours old, were inoculated intraperitoneally with 0.02 ml. of undiluted stock virus suspension (Coxsackievirus B3, Nancy prototype strain).
A Freeze-Fracture Technique for Examining Human Stratum Corneum
Authors: Hannon Daniel P. 
Published: June 2020

Human stratum corneum is a difficult tissue to process for electron microscopic examination. Most of the difficulty is due to the inability of the chemical fixative to adequately preserve all of the constituents of this tissue. As a result, during sectioning, breaks occur between cells creating voids which preclude any studies of these areas. Also, because the fixative is usually in an aqueous medium, studies of hydrated or dehydrated states are impossible. However, these problems can be overcome by using an alternative method of sample preparation, freeze-fracture electron microscopy.Samples of human skin both untreated and soaked for 20 minutes in 20% glycerin were cut into strips 1 mm wide by 2 mm long and placed in specially made copper discs with a 1 mm deep central cup. Freezing was accomplished by immersion in liquid Freon 22.
High Resolution Shadowing of DNA
Authors: Abermann R. , Salpeter M. M. 
Published: June 2020

High resolution shadowing by electron beam evaporation was used to visualize DNA molecules. Its applicability to the study of macromolecules at this resolution level was previously demonstrated on monomeric and dimeric tRNA particles.To utilize the potential of the high resolution shadowing for DNA, a mounting procedure was employed which provided a smooth substrate to which the naked molecules could be bound. This consisted of a two step process, modified from Kleinschmidt Lang, and Harford and Beer. When a 50μl droplet of cytochrome c (20 μg/ml in 0.2M Na acetate at pH 5) was allowed to stand on teflon for 20 minutes, a monolayer of protein formed on its surface. The film was picked up onto carbon coated grids, washed in ethanol and air dried. As test specimen, we used DNA from SV4O. The protein coated grids were floated for 30 minutes on buffer droplets containing 0.1-0.5 μg DNA/ml 10-3SSC and the molecules were bound to the protein monolayers by diffusion. Grids were then washed successively in 50% and absolute ethanol and air dried.
Intramitochondrial Viruses of Reptilian Cell Origin
Authors: Lunger Philip D. , Clark H. Fred 
Published: June 2020

In the course of fine structure studies of spontaneous “C-type” particle production in a viper (Vipera russelli) spleen cell line, designated VSW, virus particles were frequently observed within mitochondria. The latter were usually enlarged or swollen, compared to virus-free mitochondria, and displayed a considerable degree of cristae disorganization.Intramitochondrial viruses measure 90 to 100 mμ in diameter, and consist of a nucleoid or core region of varying density and measuring approximately 45 mμ in diameter. Nucleoid density variation is presumed to reflect varying degrees of condensation, and hence maturation stages. The core region is surrounded by a less-dense outer zone presumably representing viral capsid.Particles are usually situated in peripheral regions of the mitochondrion. In most instances they appear to be lodged between loosely apposed inner and outer mitochondrial membranes.
Tubular Structures in Endoplasmic Reticulum; Are They Viruses?
Authors: Baringer J.R. , Swoveland P. 
Published: June 2020

Recently, tubular structures 18 - 26 nm in diameter have been found within endoplasmic reticulum (ER) of endothelial and other cells in a number of conditions including normal monkey tissue, renal biopsies from human lupus erythematosus and other diseases, a variety of sarcomas, lymphomas, and leukemias, and several viral infections both in vivo and in vitro. The structures have in common a convoluted tubular form, near uniform diameter, and general appearance suggesting a resemblance to the myxoviruses.We have observed similar particles within the ER of endothelial cells within the cerebral lesions caused by herpes simplex virus (HSV) both in experimentally infected rabbits and in a human case of herpes simplex encephalitis.Rabbits inoculated on the cornea with HSV developed focal encephalitic lesions in the brainstem within 4 days; cells within the lesions contained HSV.
Cytochemical Studies of Cell Wall Biosynthesis in Staphylococcus Aureus
Authors: Koike Masaatsu , Nakashima Koichi , Iida Kyoko 
Published: June 2020

Penicillin exerts the activity to inhibit the peptide cross linkage between each polysaccharide backbone at the final stage of wall-peptidoglycan biosynthesis of bacteria. Morphologically, alterations of the septal wall and mesosome in gram-positive bacteria, which were occurred in early time after treatment with penicillin, have been observed. In this experiment, these alterations were cytochemically investigated by means of silver-methenamine staining after periodate oxidation, which is applied for detection of localization of wall mucopolysaccharide.Staphylococcus aureus strain 209P treated with 100 u/ml of penicillin G was divided into two aliquotes. One was fixed by Kellenberger-Ryter's OSO4 fixative at 30, 60 and 120 min after addition of the antibiotic, dehydrated through alcohol series, and embedded in Epon 812 (Specimen A). The other was fixed by 21 glutaraldehyde, dehydrated through glycolmethacrylate series and embedded in glycolmethacrylate mixture, according to Bernhard's method (Specimen B).
Ultrastructural Changes in the Brain Following Local Application of Guinea Pig Serum
Authors: Bystrom Barbara G. , Costin Anatol , Ross Adey W. 
Published: June 2020

It was previously reported that evoked potentials and impedance were diminished when guinea pig serum was introduced into the lateral geniculate body of the cat. The cats used in the present study were chronically implanted with electrodes and cannulae. Two hours after injection of 1 μl guinea pig serum directly into the lateral geniculate body, when electrophysiological changes were evident, the cats were sacrificed. The brains were perfused with phosphate buffered 2%Glutaraldehyde-2% formaldehyde after flushing with physiological saline. Post fixation was with 1% OsO4. Dehydration was carried out in graded Ethanol, and embedment was in Epon. The silver to silver-grey sections were intensified with uranyl acetate and lead citrate. In all cases, one lateral geniculate body was used for control and the other for experimental injection.The electron microscopy study was done "blind" in that the treatment, if any, or the site of injection, if any, was unknown by the microscopist.
Optimizing Sectioning with Diamond Knives
Authors: Sawers J. R. 
Published: June 2020

Du Pont diamond knives; although utilized in cataract surgery, precision machining and film slitting, are used primarily in ultra-microtomy. Today, we would like to describe our process for making diamond knives and then some results of our work optimizing sectioning procedures.Our diamond knives are made from gem quality natural diamonds and as such can bear tremendous compressive forces but torque, lateral or tensile forces can easily fracture the blade edge. The first step in the manufacturing process is to cleave the diamond into slabs approximately 25 mils thick along the (111) plane. After cleaving, a diamond is soldered into a slotted shaft. The first grinding step, called “roughing”, begins by tapering one side of the shaft until the diamond just becomes visible, then the other side is tapered. Grinding continues until no nicks are visible at 50x. Next, “polishing” fine grinds the knife edge until it is “nick-free” at 600x.
Scanning Electron Microscopy of the Denticles and Eggs of Ascaris lumbricoides and Ascaris suum
Authors: Ubelaker John E. , Allison Venita F. 
Published: June 2020

Morphological differences between Ascaris of human and porcine origins have been difficult to detect. Sprent has distinguished the two species by the characteristics of the denticles observed by light microscopy. The present study is concerned with the differences in morphology of the denticles and with the examination of the ova of the two species as revealed by scanning electron microscopy.Hospital and slaughter house specimens were acquired locally, fixed in phosphate buffered paraformaldehyde and stored in 70% ethanol overnight. Preparative procedures for scanning electron microscopy were as previously reported. Specimens were examined in a JEOL JSMU-3 scanning electron microscope.The denticles of Ascaris suum are regular in distribution and conoid in shape (Fig. 1, A and B). Each denticle is cuspid; no multiple cusps were observed. The “molar teeth” forms previously described probably result from observations of cusps from which adhering debris was not removed in preparation.
Frozen Resin Cracking Method for Scanning Electron Microscopy and its Application to Cytology
Authors: Tanaka K. , Iino A. 
Published: June 2020

Until recently, a few reports have been published as to the methods for observing intracellular structure by means of scanning electron microscopy. Makita and Sandborn saw intracellular granules in the glands of the hen oviduct with tissue sections by means of Smith-Farquhar tissue sectioner. Geminario and McAlear applied the freeze-fracturing technique in order to ascertain the intracellular structure of retinas from mice.A new method, attempted by us, embedding the materials in epoxy resin and cracking it into two pieces after freezing, is described below with its application to cytology.1. The pieces of tissue are fixed in glutaraldehyde and osmium tetroxide.2. They are dehydrated by graded series of ethanol and propylen oxide.3. Then they are embedded in small gelatin capsules (size no. 2) which are filled with Cemedine 1500 (epoxy resin) without any catalysts (Epon 812 or Rigolac can be used but the temperature for hardening them is very low, -80°C).
Preparation of Red-Green Stereo Lantern Slides from SEM Micrographs
Authors: Nemanic Michael 
Published: June 2020

The procedure detailed allows the projection and viewing of stereoscopic slides without the use of a special stereo projector or a polarizing screen; a standard lantern slide projector is used, and the slides are viewed through red and green acetate filters.A stereo pair is taken on a scanning electron microscope with a tilt difference of 7° (Fig. 1). After the first member of the pair is taken, the sample is tilted. The image is refocused by means of the z-axis control and recentered by means of the x- and y-axis controls. These two manipulations ensure that both micrographs in the stereo pair are at the same magnification and that they will be superimposed properly on the color slide.A Polaroid MP-3 Industrial Viewer, a Graflex 120 roll film back, and a framing table (or equivalent equipment) can be used to make stereo slides from stereo pairs.
Enhancement of EDAX Spectra from TEM and SEM Analysis
Authors: Russ John C. 
Published: June 2020

The attachment of EDAX systems to the TEM and SEM makes possible the microanalysis of features observed in the high magnification images. In general the interpretation of the resulting spectra is very straightforward, with qualitative identification of the major and minor elements present requiring only reference to a simple chart, and semiquantitative estimation of concentration possible by direct comparison of peak heights. True quantitative analysis requires more complex mathematics and/or standards but this is not generally the aim of most SEM and TEM users.There is one class of problems for which the direct interpretation of the recorded EDAX spectrum can be difficult, especially for the operator not highly trained in EDAX methods. This is the case of very low total count rates, typically encountered with low concentrations of elements in organic matrices and/or with low total specimen mass as encountered with thin sections.