bluuebunny/crossref_metadata_2025_split huggingface dataset:
Thin Graphite Supporting Films for High Resolution Work
Authors: Iijima Sumio 
Published: June 2020

Background noise arising from amorphous carbon supporting films is a crucial problem for high resolution CTEM work, particularly for biological materials. Many people have been trying to overcome this problem, for example, by use of sophisticated image analysis by computers, but without convincingly successful results so far. On the other hand, it is theoretically expected that if we use thin single crystal films the background noise can be completely eliminated. This has been attempted by a few workers (1,2) who used single crystals of BeO or graphite for observing very small metal particles or single atoms. Here we shall report a method of preparing very thin and clean single crystal films of graphite and their properties.Preparation of thin graphite films. Firstly relatively thin graphite films were prepared by repeated cleavage of a graphite crystal between Scotch tapes. Small flakes of cleaved graphite crystal stuck on the tapes were separated in ethylene dichloride.
Myoneural Junctions in Toadfish Swimbladder Muscle
Authors: Sidle James M. 
Published: June 2020

Among vertebrate striated muscles studied to date, the toadfish swimbladder muscle is fastest with an average contraction time of 5 msec. The ultrastructure of this muscle has been examined, particularly with regard to the elaborate sarcoplasmic reticulum present, and a light-microscoplc study of the neuromuscular junctions has been performed. Motorneurons which innervate the swimbladder muscle were found to be electronically coupled by way of axo-somatic and dendro-somatic junctions.The ultrastructure of the myoneural junctions in the Atlantic toadfish (Opsanus tau) was examined and the findings conform to those obtained from several other teleost twitch fibers.
Ultrastructural Changes in Friend Leukemia Cells After Dimethyl Sulfoxide (DMSO), Dimethyl Formamide (DMF), or 5-Bromo-2’-Dioxyuridine (BUdR) Treatment in Vitro
Authors: Sato T. , Harven E. de , Friend C. , Scher W. , Preisler H. D. 
Published: June 2020

Murine Friend erythroleukemia cell (FLC) lines continuously produce Friend leukemia viruses as evidenced not only by electron microscope observation but also by the immunity against challenge with leukemogenic viruses given to susceptible mice with cell free filtrate of these cultures. When these cells were cultured in the presence of 2% DMSO, 3 major changes were observed: 1)increase of the number of budding viruses; 2)an enhanced cell differentiation along the erythoid pathway; and 3) the formation of cytoplasmic complex vacuolar structures containing many viruses (CVS).We have been studying the effects on FLC of DMSO and DMF, as well as those of halogenated deoxyuridines which have been recently reported to increase the production of some murine RNA viruses, individually or in combinations.
Ultrastructural Evaluation of Ultimobranchial Thyroid Neoplasms in Bulls
Authors: Capen C. C. , Black H. E. 
Published: June 2020

The recently characterized hormone calcitonin (thyrocalcitonin) is synthesized and secreted by parafollicular (C-) cells present in the mammalian thyroid gland. Parafollicular cells are derived embryo logical ly from primordia of neural crest origin that migrate into the ultimobranchial body during early embryonic development.A syndrome of ultimobranchial thyroid neoplasms which shares many characteristics with medullary thyroid carcinoma in man occurs frequently in populations of old bulls. The development of these tumors may be related to a prolonged excessive intake of dietary calcium. Cows raised under similar environmental conditions do not develop ultimobranchial neoplasms. Affected bulls often have extensive skeletal disease and develop tumors in other endocrine organs.
Scanning and Transmission Electron Microscopy of Isolated Cells of Hydra littoralis
Authors: Westfall Jane A. , Enos Paul D. 
Published: June 2020

Using scanning and transmission electron microscopy (SEM and TEM), we observed batteries of 20-30 nematocytes, cnidoblasts, sensory cells, and other neurons invaginated within epitheliomuscular cells ofHydra. In an attempt to determine how the cells were structurally interrelated, we isolated cells ofHydra littoralisfor further study by SEM and TEM.To isolate cells, 30Hydra littoraliswere placed for 30 minutes in a P19 culture medium modified by omitting calcium and magnesium ions, adding 20% sucrose and stabilizing at pH 7.2 with sodium phosphate, then pipetted gently to free the epithelial cells from the mesoglea. Glutaraldehyde was added to make a 5% solution and the cells were fixed 1 hour at 0-4°C, centrifuged 10 minutes at 1000 X g, resuspended in cacodylate buffer twice, and placed 2 hours in 4% osmium tetroxide at 0-4°C.
Control of Secretory Production in the Isopod Hepatopancreas
Authors: Roberts John W. , Witkus E. R. 
Published: June 2020

The isopod hepatopancreas, as exemplified byOniscus ascellus. is comprised of four blind-ending diverticula. The regenerative cells at the tip of each diverticula differentiate into either club-shaped B-cells, which serve a secretory function, or into conoid S-cells, which serve in the absorption and storage of nutrients.The glandular B-cells begin producing secretory material with the development of rough endoplasmic reticulum during their process of maturation from the undifferentiated regenerative cells. Cytochemical and morphological data indicate that the hepatopancreas sequentially produces two types of secretory material within the large club-shaped cells. The production of the carbohydrate-like secretory product in immature cells seems to be phased out as the production of the osmiophilic secretion was phased in as the cell matured.
Electron Microscope Study of the Closed Circulatory System of Nereis
Authors: Nakao Taisuke 
Published: June 2020

According to the architecture of the walls, blood vessels of Nereis can be classified into three groups: I) interstitial type; 2) mesothelial type; 3) epidermal or respiratory type.Interstitial type: It is represented by the intestinal vessels which are located in the interstitial connective tissue of the gut wall between the intestinal epithelium and the muscular strata which are assumed to be derived from the mesothelium. The walls of these vessels are made of a fibrillar, collagenous, connective tissue which directly limits the contour and extension of the vascular lumen. There is no true endothelium but amoebocytes can be found scattered against the wall. On the coeliac side of the vessels, this tissue is limited by the basal lamina which is backed by the muscular strata and the mesothelial cell layer, while it is limited, on the other side, by the basal lamina of the intestinal epithelium.
Electron Microscope Observations on DNA and Chromatin Fibres of Hydra Vulgaris and Ephydatia Meyeni
Authors: Mookerjee Anjali 
Published: June 2020

The present paper reports the observations made on DNA and chromatin material obtained from Hydra vulgaris (raised in laboratory culture) and a fresh water sponge Ephydatia meyeni. Both samples were prepared following Marmur's method, with slight modifications. For the chromatin fibres, samples were used just after the cell lysis stage without any shaking or further purification procedures. The specimens for electron microscopy were prepared by the protein monolayer technique.The diameter of rotary shadowed purified DNA samples from H. vulgaris and E. meyeni was 60-80 A and the length of the Fibres varied between 5-18 /u (Fig. 1), and 5-10/u respectively.
Ultrastructural Similarities Between Adrenal Medullary and Paraganglion Cells
Authors: Mascorro Joe A. , Yates Robert D. 
Published: June 2020

The fine structural characteristics of adrenal medullary chromaffin cells to include their cytoplasmic detail, vascularity, innervation and catecholamine (CAM) content have been well studied. However, not until recently has this same interest been applied to similar chromaffin cells classified, as paraganglion cells and located in areas away from the adrenal medulla. The present results involving morphological comparisons between paraganglion (PC) and adrenal medullary cells (AMC) indicate that these cellular elements are essentially identical.Syrian hamsters were perfused with 3% glutaraldehyde in 0.1 M phosphate buffer and post fixed, in 1% osmic acid. A retroperitoneal tissue block containing the coeliac and superior mesenteric artery trunks and abdominal aorta was excised, divided into slices and flat embedded in Epon 812.
Subplasmalemmal Microfilaments and Microtubules in Cultivated Macrophages
Authors: Reaven E.P. , Axline S.G. 
Published: June 2020

Recent studies suggest that contractile microfilaments and/or microtubules may mediate cell movement and intracellular transport of cytoplasmic constituents. Current studies of control, phagocytizing and cytochalasin B (CB) treated macrophages provide evidence that membrane translocation required for endocytosis may involve similar mechanisms.Mouse peritoneal macrophages, cultivated for 48 hours, were fixed and embedded directly on glass coverslips to preserve the original orientation of the monolayers. Analysis of serial thin sections cut parallel to the plane of glass attachment disclosed a number of features of the cells not previously described.1) A loose, delicate, continuous network of 40-50 Å microfilaments extending from the inner surface of the plasmalemma to a depth of 500-600 Å were found in all regions of the cell (Fig. 1). In areas of normal pseudopodal folding or retraction, the network was thickened and of increased density. The filaments of this network were insensitive to CB treatment (5-10 μg/ml).
Alcoholic Hyalin and Cytoplasmic Filaments in Biliary Epithelial Cells
Authors: Minick Odell T. , Yokoo Hidejiro , Batti Fawzia 
Published: June 2020

Biliary epithelial cells have previously been shown to be a site of alcoholic hyalin (AH) deposition. To learn more of the nature and pathogenesis of this inclusion, the fine structure of proliferating biliary ductules was studied in 20 patients with alcoholic liver disease. The changes were compared with those observed in hepatocytes containing alcoholic hyalin.The ductular cells often displayed dilated cisternae of rough endoplasmic reticulum, prominent Golgi complexes, and an increase in lysosomes. Mitochondria were larger, more numerous and contained more cristae than those usually seen in ductules (Fig. 1). Double nuclei were common. Dense, compact cells, probably degenerative in nature, were often noted.
St. Louis encephalitis virus infection of a mosquito vector
Authors: Whitfield Sylvia G. , Murphy Frederick A. , Daniel Sudia W. 
Published: June 2020

The course of arbovirus infections in the arthropods necessary for their transmission in nature has been studied extensively, but in only a few instances at the ultrastructural level. In the present study a model system was established for the infection of Culex mosquitoes with St. Louis encephalitis (SLE) virus (arbovirus group B ), the most important mosquito-bome disease in the United States. Results were compared with those of a previous study of Eastern equine encephalitis virus (arbovirus group A) in Aedes mosquitoes (this Proceedings, 1969, pp. 378-379) since differences in sites of maturation in mammalian cells have been found between the two groups.Culex pipiens mosquitoes were infected by feeding upon suckling mice infected with SLE virus (plasma viremia titer 105.4 SMLD50/ml). Mosquitoes were then held at 27°C; they were tested for capacity to transmit virus via bite, and specimens of salivary glands and other organs were collected at 18 intervals during 32 days.
The Nature of Polyhedral Inclusion Bodies of Thiobacillus Neopolitanus
Authors: Ball F. L. , Shively J. M. , Breillatt J. P. , Caton J. E. , Brownt D. H. 
Published: June 2020

Polyhedral inclusion bodies (alpha particles) of unknown function have been observed previously in T. neopolitanus by electron microscopy of thin sections. Partial characterization of these bodies has been accomplished by means of rate-zonal centrifugation. The cells were broken by a French pressure cell, treated with deoxyribonuclease prior to centrifugation.Figure 1 is a thin section of T. neopolitanus showing bacteria with varying numbers of alpha particles.Initial attempts were made to isolate the intact alpha particles by ratezonal and isopycnic methods in both swinging bucket and zonal rotors. Nevertheless, the alpha particles were usually contaminated with membrane fragments and other cellular material as well as inner components (alpha particles) from partially ruptured alpha particles, as shown in Fig. 2.
An Electron Microscopic Study of the Human Gastric Epithelia with Special Reference to the Ultrastructural Changes of the Parietal cells Induced by “Histalog“
Authors: Saito Hiroshi , Asano Goro , Aihara Kaoru , Fukushi Katsunari , Yoshida Minoru , Kimura Ken 
Published: June 2020

This is to communicate the ultrastructural changes of the parietal cells of the human gastric mucosa in “Histalog” stimulation.Gastro-endoscopic biopsy specimens from 48 adult patients suffering from various gastritic conditions are studied. The patients are roughly divided into two groups. The first group consists of the control study. In essentially intact gastric mucosa (hyperacidic) cases, the “Histolog” 50mg had been injected intramuscularly to the subjects and chronologically endoscopic biopsy study had been achieved at 5, 10, 15, 20, 30, and 60 minutes respectively. The second group consists of the study with advanced atrophic gastritis (anacidity) and similar manipulation has been attemped. The obtained specimens were quickly fixed in 2.5% glutaraldehyde, postosmificated, and dehydrated in graded alcohols and embedded in Epon 812. Sections were cut and observed with the Hitachi 11U-B electron microscope with 50kv or 75kv accelerating voltages.
Electron Microscopic Characterization and Quantitation of Air Borne Particulate Matter with Special Emphasis on Asbestos
Authors: Mueller Peter K. , Smith Glenn R. , Carpenter Leslie M , Stanley Ronald L. 
Published: June 2020

At the present time the primary objective of the electron microscopy group of the Air and Industrial Hygiene Laboratory is the development of a method suitable for use in establishing an air quality standard for asbestos in ambient air and for use in its surveillance. The main concept and thrust of our approach for the development of this method is to obtain a true picture of fiber occurrence as a function of particle size and asbestos type utilizing light and electron microscopy.We have now available an electron micrographic atlas of all asbestos types including selected area diffraction patterns and examples of fibers isolated from air samples. Several alternative approaches for measuring asbestos in ambient air have been developed and/or evaluated. Our experiences in this regard will be described. The most promising method involves: 1) taking air samples on cellulose ester membrane filters with a nominal pore size of 0.8 micron; 2) ashing in a low temperature oxygen plasma for several hours;
Scanning Microscopy of Human Intestinal Explants in Organ Culture
Authors: Wetzel Bruce , Buscho Robert , Dolin Raphael 
Published: June 2020

It has been reported that explants of human fetal intestine can be maintained in culture for up to 21 days in a viable condition and that these organ cultures support the growth of a variety of known viral agents responsible for enteric disease. Scanning electron microscopy (SEM) has been undertaken on several series of these explants to determine their appearance under routine culture conditions.Fresh specimens of jejunum obtained from normal human fetuses were washed, dissected into l-4mm pieces, and cultured in modified Leibowitz L-15 medium at 34° C as previously described. Serial specimens were fixed each day in 3% glutaraldehyde for 90 minutes at room temperature, rinsed, dehydrated, and dried by the CO2 critical point method in a Denton DCP-1 device. Specimens were attached to aluminum stubs with 3M transfer tape No. 465, and one sample on each stub was carefully rolled along the adhesive such that villi were broken off to expose their interiors.
Hole Formation in Gold Films
Authors: Vook R. W. , Cook R. , Ziemer R. 
Published: June 2020

During recent experiments on Au films, a qualitative correlation between hole formation and deposition rate was observed. These early studies were concerned with films 80 to 1000A thick deposited on glass at -185°C and annealed at 170°C. In the present studies this earlier work was made quantitative. Deposition rates varying between 5 and 700 A/min were used. The effects of deposition rate on hole density for two films 300 and 700A thick were investigated.Au was evaporated from an outgassed W filament located 10 cm from a glass microscope slide substrate and a quartz crystal film thickness monitor. A shutter separating the filament from the substrate and monitor made it possible to obtain a constant evaporation rate before initiating deposition. The pressure was reduced to less than 1 x 10-6 torr prior to cooling the substrate with liquid nitrogen. The substrate was cooled in 15 minutes during which the pressure continued to drop to the mid 10-7 torr range, where deposition was begun.
The Structure of Graphite Fibers Utilized in Field Ionization
Authors: Bowles C.Q. , Stillie G.D. 
Published: June 2020

Field ionization mass spectrometry has become an increasingly useful analytical tool because of the absence of mass spectra cracking patterns normally associated with electron impact methods. However a rather trouble some experimental difficulty has been the development of an ionization source with ionization efficiency sufficient to produce detectable signals of trace components.A graphite filament ionizer was recently developed at our laboratory and consists of a graphite whisker mounted taut between two tungsten posts. The exposed length of filament and its diameter are nominally 8 mm and 10-3 mm (1 micron) respectively. Ion yields of 10-11 amp at 10-6 torr (10-5 amp/torr) with ion energies of 6-7 Kev are readily obtainable. The filaments have also been used for field emission and Cox has used the Fowler-Nordheim equation modified for cylinderical geometry to obtain an estimated emitter diameter of 40 Å from his experimental data.
Displaced Aperture Dark Field Images by an Aberration Correction
Authors: Shirota K. , Yamamoto T. , Yanaka T. , Vingsbo O. 
Published: June 2020

In displaced aperture dark field microscopy, the direction of the incident electron beam with respect to the specimen is maintained unaltered between bright field and dark field images, unlike the case of usual high resolution dark field microscopy by tilted illumination. The displaced aperture technique, however, gives a strong dark field image deterioration due to field aberrations. These are prounouncedly large since the deviation of the orbits of the imaging electrons from the optical axis is very large in this case. In the present paper, the improvement of the image quality by aberration correction is discussed.1. The chromatic field aberration is composed of components mainly from the objective and intermediate lenses. It can be corrected by changing the electron orbit by means of a beam deflector, introduced in the image plane of the objective lens.
Photographic Equidensitometry of High Voltage Electron Images of Thick Noncrystalline Materials
Authors: Kobayashi Keinosuke 
Published: June 2020

Equidensitometry as developed by E. Lau and W. Krug has been little used in the analysis of ordinary electron photomicrographs, yet its application to the high voltage electron images proves merits of this procedure. Proper sets (families) of equidensities as shown in the next page are able to reveal the contour map of mass thickness distribution in thick noncrystalline specimens. The change in density of the electron micrograph is directly related to the mass thickness of corresponding area in the specimen, because of the linear response of photographic emulsions to electrons and the logarithmic relation between electron opacity and mass thickness of amorphous object.This linearity is verified by equidensitometry of a spherical solid object as shown in Fig. 1a. The object is a large (1 μ) homogeneous particle of polystyrene. Fig. 1b is a composite print of three equidensities of the 1st order prepared from Fig. 1a.
Electron Microscope Image Intensification and Specimen Exposure
Authors: Heinemann Klaus , Poppa Helmut 
Published: June 2020

The efficiency of electron microscope image intensification (EMII) systems is often represented in terms of signal-to-noise ratio as a function of current density in the final microscope image plane. Such a characteristic is one way of evaluating the sensitivity of an EMII-system. It determines the intensification necessary to raise the signals of individual electrons well above the equipment noise level of the intensifier/display chain.This approach to the problem of EMU may lead to misinterpretations since it does not consider the spatial resolution in the specimen. Usually, the spatial resolution of the EMII-chain is considerably inferior to the resolution of conventional photographic material. In internal photography one can, therefore, normally work with considerably lower electron optical magnifications than with an image intensifier system to resolve specimen details of the same dimensions.
Phase Contrast Enhancement by Single Sideband Modulation Transfer
Authors: Andersen Willem H.J. 
Published: June 2020

Through-focal series of an empty carbon film with the corresponding optical diffractograms illustrate beautifully the contrast transfer theory of the electron microscope. This theory has gained great popularity among the electron microscope designers because it presents a means of obtaining an image quality figure for the instrument independent of the object, by using the contrast transfer function. Present objective lenses are nearly perfect in the sense that they perform close to the theoretical expectations. Paradoxically, this presents a serious problem for the biological electron microscopist who wants a faithful image of his sample at high magnification.Biological E.M. samples are weak phase objects and consequently the E.M. is in principle not able to image the object with any contrast. Due to spherical aberration and defocussing, details < 10 Å are transferred, but the oscillating nature of the transfer function causes image interpretation problems. Staining of the object to obtain contrast is very unsatisfactory and methods have been sought to image phase structures from 5 Å upward with enhanced contrast.
Technique For Examining the Structure of Sputtered MoS2 Lubrication Films by Ion Erosion and Transmission Electron Microscopy
Authors: Shaw G. G. , Lavik M. T. 
Published: June 2020

Sputtered MoS2 films have exhibited good friction and wear characteristics; and to reveal the morphology and crystal structure of the rather thick films, the following methods were used.MoS2 was sputtered onto mechanically polished 1/8 in. thick 1100 aluminum blocks to a thickness of approximately 2 microns. The temperature of the blocks during sputtering was held at around 200°C by water cooling the sample holder. These conditions have yielded films of good lubrication properties. The sputtered surface was then coated with a heavy film of formvar and when dry, was scored into 1/8 in. squares and the squares floated off with a 4% solution of HgCl2 and then thoroughly washed in water. Since we wanted to examine the metal MoS2 interface, the center of the film, and the free surface; ion milling was chosen as a means of thinning to electron transmission thickness.