bluuebunny/crossref_metadata_2025 huggingface dataset:
Application of the Ussing Transport Chamber to the Study of Ultrastructure and Function in Injured Cells
Authors: Saladino Andrew J. , Trump Benjamin F.
Published: June 2020

The Ussing transport chamber is a two compartment system separated by an intact epithelial layer. Manipulation and analysis of these compartments and epithelium provide electrophysiological, biochemical and morphological data concerning the partitioning cellular complex. Control over many environmental variables is facilitated. This chamber, therefore, provides a simple system for study of the alterations of morphology and function that follow specific injurious events.

In the present studies the toad bladder was the partitioning cellular complex and inhibition of energy metabolism the specific injury. Incubated control preparations consisted of bladder halves incubated in a balanced salt solution and allowed to function over an extended time period (~15 hours) without exogenous substrate. Experimental preparations were treated with 10-3 M cyanide and 10-4 M iodoacetate for a similar period. The transepithelial potential difference was monitored continuously and tissue was removed for study by electron microscopy.
Cytological Preservation Using 1,5-Difluro 2, 4-Dinitrobenzene
Authors: Philpott Delbert E.
Published: June 2020

A protein cross-linking agent, 1,5-difluro 2,4-dinitrobenzene (DFF) has been used for the preservation of red blood cells, liver and cartilage. This difluro compound is known for Its cross-linking ability which results in the stabilization of membranes by reacting with the free amino groups; this removes the positive charge by removal of a hydrogen atom. The double site on the difluro compound can react if the two amino groups are 5Å or more apart. It also reacts with sulfhydryl, tyrosyl or histidyl groups to form stable dinitro phenyl derivatives. The present studies indicate that preservation extends into the ultrastructure level and demonstrates a method for holding biological material for prolonged periods.
Fine Structure of Carotid Body: Normal and Anoxic Cats
Authors: Al-Lami Fadhil , Murray R.G.
Published: June 2020

Although the fine structure of the carotid body has been described in several recent reports, uncertainties remain, and the morphological effects of anoxia on the carotid body cells of the cat have never been reported. We have, therefore, studied the fine structure of the carotid body both in normal and severely anoxic cats, and to test the specificity of the effects, have compared them with the effects on adrenal medulla, kidney, and liver of the same animals. Carotid bodies of 50 normal and 15 severely anoxic cats (9% oxygen in nitrogen) were studied. Glutaraldehyde followed by OsO4 fixations, Epon 812 embedding, and uranyl acetate and lead citrate staining, were the technics employed.

We have called the two types of glomus cells enclosed and enclosing cells. They correspond to those previously designated as chemoreceptor and sustentacular cells respectively (1). The enclosed cells forming the vast majority, are irregular in shape with many processes and occasional peripheral densities (Fig. 1).
Sequence of Changes in the Fine Structure of the Retina of Dogs Irradiated During Retinal Maturation
Authors: Shively James N. , Phemister Robert D. , Epling Glenwood P.
Published: June 2020

It has been known since early in this century that exposure to ionizing radiation during maturation of the mammalian retina results in necrosis of post-mitotic differentiating cells in the nuclear layer, followed by marked retinal dysplasia with rosette formation, and partial to complete agenesis of outer segments of photoreceptor cells. The effect has been morphologically related to the area of the retina undergoing differentiation at the time of irradiation. Alteration in spacial and pressure relationships are said to result in the tubular rosette formations. These effects have been described in mice, rats, monkeys, dogs and man. Doses less than 25 R have produced severe dysplasia in the developing retina of mice. The mature retina is damaged only by doses of several hundred to a few thousand R.
Fine Structure of the Connecting Piece of the Spermatozoon
Authors: Stefanini Mario , Zamboni Luciano
Published: June 2020

Past studies have demonstrated that the connecting piece of the mammalian spermatozoon consists of several components; namely, the “proximal” centriole, the segmented columns, the fibrils of the axial filament complex, and mitochondria. Little is known, however, of the anatomical and functional relations which bind these structures together. This prompted us to investigate the structural organization of the connecting piece by means of tridimensional studies on thin sections of human and rabbit spermatozoa from testis and epididymis.

The connecting piece has the shape of an inverted cone. At its base lies the proximal centriole which is inclined at an angle of about 45° to the long axis of the flagellum. The nine dense fibers of the flagellum are continuous with the segmented columns (Figs. 1 and 4) which form the wall of the connecting piece. Fusion of fibers 9, 1 and 2 on one side (Fig. 3), and 5 and 6 on the other induces formation of two major segmented elements and reduces to six the total number of columns. However, the nine original columns become reconstituted at the proximal end of the connecting piece where the fused elements of the major columns separate again.
The Ultrastructural Basis of Cellular Swelling
Authors: Trump Benjamin F. , Ginn Fred L.
Published: June 2020

Cellular swelling is a common early reaction of cells to injury. In order to study the detailed pathogenesis of this reaction we have employed the isolated flounder kidney tubule system described previously. Tubules were teased from freshly-removed kidneys of Paralichthys lethostigma or Parophrys vetulus and incubated at ~20°C in a medium with the following composition (millimoles/liter): NaCl, 135, KC1, 2.5, CaCl2, 1.5; MgCl2, 1.0; NaH2PO4, 0.5; NaHCO3, 10; and chlorphenol red, 0. 02 or Diodrast 1131, 0. 01. The medium was oxygenated and active transport studied by following dye or Diodrast accumulation. Composition of medium and/or incubation temperature was modified as indicated. Cell swelling was assessed by light microscopy of unfixed tubules.
Special Cutaneous Receptor Organs of Fish: Synaptic Structures of Eigenmannia
Authors: Szamier R. Bruce , Wachtel Allen W.
Published: June 2020

Special cutaneous receptor organs of fresh-water weakly electric fish are grossly similar to other receptor organs of the acoustico-lateralis system, but differ in numerous cytological details. They are presumed to function as detectors of weak electric currents. Those of Eigenmannia are of two types that have been designated tuberous and ampullary receptor organs. Parts of the lateral and basal surfaces of the receptor cells are in contact with accessory cells. A single relatively large, almost spherical, nerve ending is inserted between the basal end of each receptor cell and the subjacent accessory cell, lying within a hemispherical concavity in the base of the receptor cell.

The presumed synaptic areas between each receptor cell and the nerve ending associated with it are not contiguous, but are morphologically discrete structures, separated by nonsynaptic areas of membrane (Fig. 1). Approximately thirty synaptic areas are found on each receptor cell in both kinds of organs. The surface contours of the apposed cell membranes are irregular in the nonsynaptic areas, and hence the extracellular space is variable in width. In the synaptic areas the membranes of both cells appear slightly thickened (Fig. 2), and are separated by a constant gap of about 200 Å. Fine fibrillar material spans the synaptic gap.
A Slotted Electrode Stigmator for Correction of Short Focal Length Objectives
Authors: Reisner J. H. , Schuler J.J
Published: June 2020

One of the difficulties which must be overcome in the design of objective lens stigmators is that they necessarily take up space where it is most precious, in the vicinity of the specimen. The space following the specimen is needed for the contrast aperture while the space between magnetic poles in the gap is required for stage mechanism. To go appreciably below the objective back focal plane to position stigmators subjects the image to possible image distortion when correction is large. A further problem is caused by the trend to shorter objective focal lengths, e.g., 1.5 mm, thus further reducing the space available for the stigmator.

To adapt the electrostatic stigmator to these physical restraints, a design has been completed which is only 0.75 mm thick and has a free bore diameter of the same size. Its sensitivity is 0.1 micron/volt with 100 kV electrons. The overall diameter is uncritical and may be adapted to the physical requirements of the system. It should be possible to make stigmators of 3 mm thickness with a simple reduction of critical dimensions (thickness and slot width).
Electron Accelerator for a 1-MeV Electron Microscope
Authors: Reinhold Guenter
Published: June 2020

Highly stabilized electron accelerators are required for the supply of high energy microscopes, such as the 1-MeV microscope installed by RCA at the Research Center of the US Steel Corporation at Monroeville, Pa. As shown in figure 1, the accelerating voltage is generated by a 5-stage Cockcroft-Walton cascade rectifier with an additional filter stack. The accelerator structure is connected to the cascade generator through a high-ohmic damping resistor which also serves as a filter resistor in connection with the capacitive part of the precision voltage divider in parallel to the accelerating tube. The beam tube consists of porcelain isolators sealed together by metal flanges and double 0 rings. The accelerating electrodes are made of highly polished mumetal as well as the cylindrical shields which cover the accelerating gaps. Entire mumetal screening is necessary to minimize the effect of the magnetic field of the earth on the electron beam. The beam tube is surrounded by several insulating cylinders which include the voltage divider, a bleeder-chain, a coupling capacitor for the compensation of the residual ripple voltage, and six insulating shafts which are used to control the electron gun and the injector system at high voltage potential.
The Effect of Vacuum on the Structure of Vapor Deposited In, V, and Mn
Authors: Murr L. E.
Published: June 2020

It has been observed by transmission and diffraction electron microscopy that the nominal background pressure just prior to the vapor deposition of certain metals, particularly those possessing more than one structure possibility, can be influential in determining the crystallographic structural phase which will form. Previous experimental investigations along this line have also revealed the fact that the nominal system pressure influences such structural features as grain size and epitaxy.
Evaporated Copper Deposits on Nickel Substrates
Authors: Goodman William L. , Lawless Kenneth R.
Published: June 2020

The structure of thin copper electrodeposits on single crystal nickel substrates has been previously studied in this laboratory. We thought it would be desirable to prepare similar bi-crystal films by the evaporation of copper onto nickel so that a comparison of the structures obtained by the two methods of deposition could be made. For this purpose, single crystal nickel films of (100), (110) and (111) orientations were prepared by evaporation onto heated (410°C) rocksalt substrates. Without breaking the vacuum, copper was evaporated in the form of a thin wedge onto the nickel surfaces after the nickel was cooled to room temperature. High purity (99.999%) metals were used, and these were thoroughly outgassed before evaporation. The thickness gradient of copper was obtained by moving a shutter between the substrate and the copper source during the evaporation. The resulting bi-crystal films were then stripped from the rocksalt and examined by transmission electron microscopy.
Electron Microscopic Study of Quench-Hardening in Aluminum
Authors: Mori T. , Meshii M.
Published: June 2020

Fundamentals of the morphology of plastic deformation in quench-hardened aluminum single crystals were studied. The study confirmed the correspondence of the loop-depleted zone (channeling) to the slip bands which was previously reported in polycrystalline specimens. Furthermore, kinetics of formation and growth of the slip bands were studied as a function of plastic strain.

Single crystals of 99.999% aluminum, grown by the strain anneal method from sheets of 0.8 mm. thickness, were quenched from 640°C into brine at -40°C and aged for 2 hours at 60°C. The density of vacancy loops, approximately 170 Å in diameter, which was produced by this quenching and aging treatment is about 1015/cm3. Tensile tests were performed with an Instrom machine with the strain rate of 2 x 10-4/sec.
Identification of BetaSiC Precipitate Formed in p-Type Silicon Single Crystals during Annealing
Authors: Tufts Charles F.
Published: June 2020

Using high energy reflection electron diffraction, Newman (1) identified a precipitate of PSiC structure below the surface of silicon single crystals annealed in the range of 1000°-1250°C. This structure is cubic with SG: TD2 and ao = 4.358 Å. Most crystals were in the size range: 0.3-0.7μ. PSiC was not detected unless the silicon contained both aluminum and an n-type doping impurity such as phosphorus. Dislocation densities to 3 × 104/cm2 were present.

Similar studies at this Laboratory showed that βSiC structure could be detected in silicon single crystals without the presence of aluminum and n-type impurities. In our work, accelerating voltage for electron diffraction was 100 kV; a double condenser was the only lens; camera length was 50 cm; direct beam spot size was 35-50μ at the plate plane. Specimens were p-type (111) Si wafers grown by Czochralski methods; resistivities were 50-60 ohm cm; boron was the major impurity.
Systematic Reflections and the Two Beam Concept of Extinction Distance
Authors: Sheinin S. S. , Cann C. D.
Published: June 2020

The effects of systematic reflections on the variation of diffracted beam intensity with depth in a crystal can only be taken into account by using the multi-beam dynamical theory. The results of calculations of this kind, which are presented here, indicate that the intensity profiles obtained are not periodic. Since extinction distance is a concept strictly applicable only when the diffracted beam intensity varies periodically with depth, its use as a parameter in describing multi-beam intensity profiles must be carefully considered.
Oriented Overgrowths on Sodium Chloride
Authors: Rosauer E. A. , Wagner C. B.
Published: June 2020

Replica studies of a freshly-cleaved surface of a NaCl single crystal which had been treated for 15 seconds with a relatively impure (bulk) methanol revealed the presence of a large number of three-dimensional oriented overgrowths having cubic symmetry (Fig. 1). Attempts to reproduce such morphological surface phenomena about 6 months later with the same methanol were not successful, possibly due to “aging” of the methanol. Treatment for 15 seconds with A.C.S. methanol did not result in any significant surface morphology. So far, the nature of the impurity in the bulk methanol has not been identified; however, analyses indicate that it is present in an amount less than 0.15%. All surface treatments of NaCl were followed by a 5-second rinse in A.C.S. acetone and another 5-second rinse in petroleum ether (Skelly B). Neither rinse contributed to surface morphology. Freshly cleaved NaCl surfaces were also treated with 1.25% by weight of A.C.S. NH4Cl in A.C.S. methanol and 1.36% by weight of U.S.P. 37% formaldehyde-water-methanol solution in A.C.S. methanol.
Epitaxial Growth of Cadmium Sulfide Films Evaporated Upon Mica
Authors: Shimaoka G. , Walch A. S.
Published: June 2020

It has been reported that thin cadmium sulfide films evaporated onto a glass substrate show strong preferred orientation with the (0001) plane parallel to the substrate surface. Escoffery has reported highly oriented CdS crystals evaporated onto mica heated at 250°C. The purpose of the present experiment is to study the structure and orientation of thin CdS films evaporated onto a mica substrate as a function of the substrate temperature and to find the temperature of optimum epitaxial growth.

Cadmium sulfide was evaporated onto a freshly cleaved mica surface heated at various temperatures between 25° and 500°C in a vacuum of ∼ 1 × 10−4 torr. Average thickness of the evaporated films was about 500Å. The evaporated specimens were divided into two parts. The first part was examined by reflection electron diffraction for several different azimuthal positions of the deposits on the mica surface. The other part was used for direct transmission electron microscopy.
Closing the GAP—A 5Å Scanning Microscope
Authors: Crewe A. V.
Published: June 2020

We have become accustomed to differentiating between the scanning microscope and the conventional transmission microscope according to the resolving power which the two instruments offer. The conventional microscope is capable of a point resolution of a few angstroms and line resolutions of periodic objects of about 1Å. On the other hand, the scanning microscope, in its normal form, is not ordinarily capable of a point resolution better than 100Å. Upon examining reasons for the 100Å limitation, it becomes clear that this is based more on tradition than reason, and in particular, it is a condition imposed upon the microscope by adherence to thermal sources of electrons.
Secondary Electron Detection in a Field Emission Scanning Microscope
Authors: Crewe A. V. , Isaacson M. , Johnson D.
Published: June 2020

A scanning microscope using only a field emission gun, without auxiliary lenses, has been described elsewhere. It has been shown capable of 100 Å resolution using transmitted electrons with a beam current of 10-10 amps. Detectors have now been installed to test its performance using secondary electrons.

Detection of secondary electrons in this microscope differs in some ways from detection in a conventional scanning microscope. First, the operating vacuum of 10-9 to 10-10 Torr places restrictions on detector construction and materials. Second, the high beam current reduces the noise restrictions on detector and amplifier. Third, the large possible working distance (up to ∿ 8 cm for a beam diameter of 200 Å) increases flexibility in the mechanical design.
Fiber-Matrix Bonding in Boron-Reinforced Aluminum Composites
Authors: Corvin I. , Morrow H. , Johari O. , Parikh N.
Published: June 2020

A significant amount of research has been done in the past few years in the development of suitable composite materials in general and on boron fiber-aluminum matrix composites in particular. The mechanical properties of the composite depend on the structures and strengths of the matrix and fibers; on the amount, distribution, and surface characteristics of the fibers; and on the quality of the bond at the fiber-matrix interface. The results presented here illustrate the application of the SEM in studying the structure of the fiber-matrix interface and the fracture features of boron and aluminum.
Copper Localization in Cirrhotic Rat Liver by Scanning Electron Microscopy
Authors: Russ J. C. , McNatt E.
Published: June 2020

In order to study the retention of copper in cirrhotic liver, rats were made cirrhotic by carbon tetrachloride inhalation twice weekly for three months and fed 0.2% copper acetate ad libidum in drinking water for one month. The liver tissue was fixed in osmium, sectioned approximately 2000 Å thick, and stained with lead citrate. The section was examined in a scanning electron microscope (JEOLCO JSM-2) in the transmission electron mode.

Figure 1 shows a typical area that includes a red blood cell in a sinusoid, a disse, and a portion of the cytoplasm of a hepatocyte which contains several mitochondria, peribiliary dense bodies, glycogen granules, and endoplasmic reticulum.
Lattice Defects in the Li2 Superlattice
Authors: Kear B. H.
Published: June 2020

At the AB3 composition, four families of phases exist that can be classified according to various stacking schemes of identical close-packed octahedral planes. These are listed in Table I. The noteworthy feature of all four stacking variants is that each A atom is surrounded by 12 nearest neighbor B atoms.

1. Stacking Faults

Stacking faults in the fee (Li2) superlattice are of three basic types - superlattice intrinsic (or extrinsic) faults, antiphase boundary faults, and complex faults.
Residual Gas Reaction in the Electron Microscope: II The Design of a Gas-Control Chamber for Quantitative Observations
Authors: Calbick Chester J. , Hartman Richard E.
Published: June 2020

Quantitative studies of the phenomenon associated with reactions induced by the electron beam between specimens and gases present in the electron microscope require precise knowledge and control of the local environment experienced by the portion of the specimen in the electron beam. Because of outgassing phenomena, the environment at the irradiated portion of the specimen is very different from that in any place where gas pressures and compositions can be measured. We have found that differential pumping of the specimen chamber by a 4" Orb-Ion pump, following roughing by a zeolite sorption pump, can produce a specimen-chamber pressure 100- to 1000-fold less than that in the region below the objective lens.
Some Recent Developments in the MAC 700 Scanning Electron Microscope
Authors: Buchanan R. , Yew N.
Published: June 2020

There has been much interest recently in combining the features of the high resolution scanning electron microscope and the x-ray microprobe analyzer in one instrument. The instrument described here is a high resolution scanning electron microscope to which a single fully-focusing x-ray spectrometer with associated signal processing and readout electronics has been added.
An Ultrahigh-Vacuum Specimen Chamber for In-Situ Electron Microscopy of Vapor Deposition Processes
Authors: Moorhead R. Dale , Poppa Helmut
Published: June 2020

The electron microscope has often been used in the past to study in-situ the details of thin film nucleation and growth processes. However, a lack of adequate control of important experimental deposition parameters, such as substrate cleanliness, residual gas pressure and composition, and super-saturation ratio, has limited the usefulness of the technique and in most cases prevented the acquisition of reliable quantitative results.

Accordingly, a new specimen chamber for use on a RCA EMU-4 instrument was built that regularly reaches base pressures of 3x10-10 torr, maintains pressures of less than 5x10-9 torr during the vapor deposition phase, and affords accurate control of the other deposition parameters.
Strioscopic Electron Microscopy
Authors: Johnson H. M. , Parsons D. F.
Published: June 2020

The dark field technique of strioscopy has provided high contrast with reasonable resolution at the organelle level for diffusely scattering, biological-type specimens and information concerning scattering processes in electron microscopy. It has involved the removal of the direct beam from the diffraction pattern by a central wire and subsequent image formation by diffracted beams, limited by a central back focal plane aperture. Strioscopic apertures (Fig. 1) have been constructed by microwelding 10µ platinum wire onto conventional platinum objective apertures. These strioscopic apertures were carried in the normal objective lens aperture holder. The focal length of a Siemens Elmiskop IA E/M was shortened to achieve coincidence of aperture and diffraction planes (Fig. 2).
Resolving Crystallites in Zirconium Oxide Films
Authors: Ploc R.A.
Published: June 2020

The optic axis of an electron microscope objective lens is usually assumed to be straight and co-linear with the mechanical center. No reason exists to assume such perfection and, indeed, simple reasoning suggests that it is a complicated curve. A current centered objective lens with a non-linear optic axis when used in conjunction with other lenses, leads to serious image errors if the nature of the specimen is such as to produce intense inelastic scattering.
Information Storage in Microspace
Authors: Newberry S. P.
Published: June 2020

The orderly storage and use of information is becoming a major concern of our culture. There is considerable interest in a system compatible with both human and machine comprehension and with access to the total of publicly held information in addition to the total of one's personal accumulation. It is therefore axiomatic that the data be a combination of digital, alpha-numeric, and pictorial formats.
Design of an Electron Microscope for High Resolution and Image Quality
Authors: Watanabe M. , Yanaka T. , Suzuki S. , Fujisawa M. , Nagakama Y. , Russ J.
Published: June 2020

With the commercial introduction of the JEM-100B having a guaranteed 2Å resolution it has been necessary to improve many design features over conventional electron microscopes in order to achieve the required stability and performance. Starting with the high voltage power supply we have reduced the ripple from conventional levels by improving the feedback resistor. The new resistor is a double coaxial cylinder so that the outer cylinder acts as a shield, eliminates voltage gradients and hence prevents circulation of the insulating oil. This reduces superimposed noise voltages in the high voltage for an overall stability better than 10-6 per minute. The high voltage system is designed for 20, 40, 60, 80, 100 kV operation, which can be switch-selected with no change in magnification, illumination or image motion.
Observation of Crossed [111] Planes in Silicon and Germanium
Authors: Phillips V. A. , Hugo J. A.
Published: June 2020

We previously described the resolution of a single set of {111} atomic planes in silicon and germanium using the 2-beam tilted illumination technique. In such an image, the position of the planes, but not of the atom rows, is defined. This work has now been extended to the simultaneous resolution of two sets of {111} planes which are inclined at 70° 32' to each other in the diamond cubic structure. The planes are normal to the (011) crystal slice plane and parallel to the microscope axis. In the 3-beam tilted illumination technique used, the zero order beam and two first order {111} beams are arranged on a circle centered on the optical axis of the microscope, and are allowed to pass through the objective aperture so that they are recombined in the image. The image is produced by phase contrast.
Residual Deformation Twin Structure in Planar Shock-Loaded Inconel 600
Authors: Murr L. E. , Foltz J. V.
Published: June 2020

Following the initial observations of twins in explosively shock-loaded nickel by Nolder and Thomas, numerous occurrences of deformation twins in shock-loaded metals and alloys of low stacking-fault energy (<40 ergs/cm2) have been observed to contribute in a significant manner to their residual mechanical properties. In many cases, the microtwin structures have exhibited pronounced deviations from pronounced twin compositions, suggesting in most instances that the planar defects were in fact composed of a combination of HCP phase bundles, stacking faults, and twins. The strengthening afforded by these planar twin-faults has been attributed mainly to the, locking of dislocations within their small volumes; and their ability to effectively block dislocation motion in the matrix.
Fracture Characteristics of Ferrous and Nickel Base Alloys Under Accelerated Stress Corrosion
Authors: Herfert R. E.
Published: June 2020

The mechanical property evaluation of ferrous and nickel base alloys under stress corrosion conditions requires testing times of many thousands of hours. This study was designed to achieve an experimental technique for accelerating this testing without changing the nature of the mechanisms operating during the long-time test. An increasee concentration of NaCl aqueous solution was used to provide the accelerated environment.
New Dimensions in Freeze-Etching
Authors: Steere Russell L. , Moseley Michael
Published: June 2020

A redesigned specimen holder and cap have made possible the freeze-etching of both fracture surfaces of a frozen fractured specimen. In principal, the procedure involves freezing a specimen between two specimen holders (as shown in A, Fig. 1, and the left side of Fig. 2). The aluminum specimen holders and brass cap are constructed so that the upper specimen holder can be forced loose, turned over, and pressed down firmly against the specimen stage to a position represented by B, Fig. 1, and the right side of Fig. 2.
The Ultrastructure of Human Sputum
Authors: Siegesmund K. A. , Pendharker M. B. , Kory R. D. , Boren H. G. , Pederson H. J.
Published: June 2020

Specimens of human sputum were obtained from normal individuals and from hospital patients with chronic respiratory diseases. In each case a fresh sample of sputum was placed immediately into a fixative containing 3% phosphate buffered osmium tetroxide for a period of two hours. The specimen was rapidly dehydrated in a graded series of alcohols, stained with a 0.1%solution of phosphotungstic acid in propylene oxide and embedded in Epon 812. The sections were examined at 100 kv in an RCA EMU 3b electron microscope.
Localization of Marek's Disease Herpesvirus and Its Antigen by Electron Microscopy and Fluorescent Antibody Techniques
Authors: Nazerian K. , Sprandel Barbara J. , Purchase H. G.
Published: June 2020

Monolayer cultures of chicken embryo fibroblasts (CEF) and duck embryo fibroblasts (DEF) grown in 35 mm falcon plastic petri dishes were infected with high tissue culture passaged JM strain of Marek's disease herpesvirus (MDHV). Forty eight to 72 hours after infection, representative plates from both cultures with well developed and isolated microplaques located in the center of the dish were stained by the indirect fluorescent antibody (FA) technique. The cultures were examined with the fluorescence microscope and well developed microplaques were photographed and marked. The same cultures were then fixed in osmium tetroxide and embedded in situ. A portion of the monolayer containing the marked microplaque was sectioned and examined with the electron microscope.
Ultrastructural Studies of the Femoral Tendon Cells in the Freshly Molted Cockroach Nymph
Authors: Hagopian Martin , Spiro David
Published: June 2020

In our electron microscopic studies of the freshly molted cockroach,Leucophaea maderae, the tendon (epidermal) cells in the nymph's femur show some characteristic features which have hitherto not been described. Within an hour of ecdysis the majority of tendon cells are attached to the cuticle and adjacent tendon cells; others are joined to the cuticle on one side and fastened to muscle on the opposite side; and some are apparently migrating free in the hemolymph. The tendon cells, whether adjacent to the cuticle or within the hemolymph, display very large numbers of microtubules and also have regions which contain rough endoplasmic reticulum and secretion granules (Fig. 1). The microtubules are oriented parallel to the myofilaments in underlying muscle cells.
Aldehyde Fixation and Fine Structural Localization of Alkaline Phosphatase Activity in Intestinal Epithelial Cells
Authors: Makita T. , Sandborn E.B.
Published: June 2020

A high level of enzymatic activity can be retained in tissues which have been fixed for very brief periods of time (5 to 10 minutes) by perfusion in aldehyde-DMSO solutions. Following the combination of short fixation time and the lead citrate method for alkaline phosphatase, membranes in the normal rat duodenum were studied.

Tissues fixed in glutaraldehyde (4%), paraformaldehyde (4%), and a mixture of the two fixatives all containing 5% DMSO and 5% sucrose in a 0.1M cacodylate buffer were compared.
Electronhistochemical Demonstration of Increased Capillary Permeability in Cholera
Authors: Merrill Thomas G. , Sprinz Helmuth
Published: June 2020

Our earlier studies of experimental cholera in pretreated guinea pigs and accidental laboratory infected human cholera cases had led us to believe that the action of the choleragenic moiety was directed at the small intestinal vasculature. This lesion (Fig. 1) was characterized by progressive degenerative endothelial changes accompanied by a rapid inflammatory response. At that time we proposed that the endothelial lesion was morphological evidence of increased capillary permeability and was the underlying cause, together with altered epithelial secretory activity, of the characteristic diarrhea of cholera. To test this hypothesis, experiments were undertaken to delineate the route and, if possible, rate of fluid passage out of the intestinal microcirculation using injected horseradish peroxidase as an electron dense tracer.
Ultrastructural Cytopiasmic Changes of Adrenal Cortex During Pregnancy
Authors: Murad T. M. , Israel Karen , Geer Jack C.
Published: June 2020

Adrenal steroids are normally synthesized from acetyl coenzyme A via cholesterol. Cholesterol is also shown to enter the adrenal gland and to be localized in the lipid droplets of the adrenal cortical cells. Both pregnenolone and progesterone act as intermediates in the conversion of cholesterol into steroid hormones. During pregnancy an increased level of plasma cholesterol is known to be associated with an increase of the adrenal corticoid and progesterone. The present study is designed to demonstrate whether the adrenal cortical cells show any dynamic changes during pregnancy.
Microtubules of the Hindgut Epithelium in the Woodlouse, Oniscus Ascellus
Authors: Witkus E. R. , Grillo Ramon S. , Smith William J.
Published: June 2020

Cytoplasmic microtubules are recognized as universal components of both plant and animal cells. They have been strongly implicated in supplying asymmetric cells with both structural rigidity and form, and as orienting units for cellular organelles. The present report describes unusually large concentrations of microtubules in the hindgut of the terrestrial isopod, Oniscus ascellus.
Electron Microscopy of Clam Myocardium Under Normal and Experimental Conditions
Authors: Sitzenstock Nan E. , Baxter William D.
Published: June 2020

The effect of 2,4-dinitronhenol (DNP) on the fine structure of the myocardium of several vertebrates has been reported by DiDio. We have studied the effects of DNP and lowered oxygen tension on the myocardium of a fresh water clam, an invertebrate.

The clam, Amblema plicata (Say, 1817), was used in this investigation. All specimens were maintained in stream water saturated with oxygen unless otherwise noted. Control and experimental animals were opened and the still-beating heart fixed in cold, buffered 1.2% osmium tetroxide. Small blocks of ventricle were dehydrated through an ethanol series, equilibrated in propylene oxide, and embedded in Araldite.
Lysosomal Multilaminate Organelles in a Platyhelminth Parasite
Authors: Krupa Paul L. , Cousineau Gilles H. , Bal Arya K.
Published: June 2020

The surface layer of flatworm parasites is an anucleate cytoplasmic tegument connected to subsurface cytons via internuncial processes. A sound concept of host-parasite interactions is contingent upon a more thorough understanding of the apical cytoplasmic contents of these parasites.
X-Ray Diffraction of Membrane Structure Changes Occurring During E.M. Specimen Preparation
Authors: Parsons Donald F.
Published: June 2020

Models representing the internal arrangement of lipid and protein of cell membranes continue to be debated with little new structural evidence to decide between them. X-ray diffraction is limited to the situation that the membranes occur, or can be placed, in very regular stacks to give a total thickness of at least 0.5 mm. Isolated preparations of membrane fragments cannot yet be packed sufficiently well for this X-rapurpose, andy patterns are obtained only after partial drying of the pellet of membranes. Such patterns are likely to result from re-crystallization of the lipid which occurs during the drying. By far, the best material for X-ray diffraction studies of membranes is the well stacked myelin of peripheral nerves. Six orders of exact diffraction data can be obtained and the reflections can be phased by a new heavy metal labelling technique. This material makes possible a close comparison between the structure indicated by the calculated electron density distribution across the membrane and the structure revealed directly by electron microscopy.
Interlocking Subunit Arrays Forming Nexus Membranes
Authors: McNutt N. Scott , Weinstein Ronald S.
Published: June 2020

The nexus is commonly considered to be a region of contact or fusion of the outer surfaces of the plasma membranes belonging to adjacent cells. In this study, examination of unfixed nexus membranes by the freezecleave technique reveals a unique assembly of membrane subunits. Limited portions of this subunit array have been previously revealed by thinsection techniques, negative staining of isolated nexuses, and freezecleaved (and etched) aldehyde-fixed nexuses.
Site of Lysosome Production During Hepatic Injury
Authors: Unakar Nalin J.
Published: June 2020

The increased number of lysosomes as well as the close approximation of lysosomes to the Golgi apparatus in tissue under variety of experimental conditions is commonly observed. These observations suggest Golgi involvement in lysosomal production. The role of the Golgi apparatus in the production of lysosomes in mouse liver was studied by electron microscopy of liver following toxic injury by CCI4.
Nucleolar Segregation and Chronic Methanol Intoxication
Authors: Garcia Julio H. , Van Zandt Janice P.
Published: June 2020

Repeated administration of methyl alcohol to Rhesus monkeys (Maccaca mulata) by intragastric tube resulted in ultrastructural abnormalities of hepatocytes, which persisted in one animal twelve weeks after discontinuation of the methyl alcohol regime. With dosages ranging between 3.0 to 6.0 gms. of methanol per kg. of body weight, the serum levels attained within a few hours averaged approximately 475 mg. per cent.
Developmental Stages in African Swine Fever Virus (ASFV) Infection
Authors: Breese Sydney S.
Published: June 2020

The continuing study of ASFV infection has proceeded by several different routes in determining the sequence of events of its adsorption, uncoating, replication and release in host cells of primary swine kidney tissue culture. Most of the studies have been based on electron microscopy, but other techniques have been used to explain or confirm what has been seen in the electron microscope.
Cytoplasmic Tubules in Cells Infected with Laryngotracheitis Virus
Authors: Watrach A. M.
Published: June 2020

During a study of the development of infectious laryngotracheitis (LT) virus in tissue culture cells, unusual tubular formations were found in the cytoplasm of a small proportion of the affected cells. It is the purpose of this report to describe the morphologic characteristics of the tubules and to discuss their possible association with the development of virus.

The source and maintenance of the strain of LT virus have been described. Prior to this study, the virus was passed several times in chicken embryo kidney (CEK) tissue culture cells.
Transovum Transmission of a Polyhedrosis Virus and a Microsporidian Parasite in the Pink Bollworm and Corn Earworm
Authors: Adams J. R. , Wilcox T. A. , Bullock H. R. , H. T. Dulmage
Published: June 2020

Rearing of pink bollworm,Pectinophora gossypiella(Saunders) and corn earworm,Heliothis zea(Boddie) have been plagued sometime with cytoplasmic polyhedrosis and a chronic microsporidian infection. This problem inspired us to make histopathological examinations of egg, larval, and adult stages of specimens from the rearing stocks of these species in Brownsville, Texas, Tucson, Arizona and our laboratory.
Freeze-Etch Crystal-Like Structures in Membranous Glomerulosclerosis
Authors: Silver Burton B.
Published: June 2020

Tissue from a non-functional kidney affected with chronic membranous glomerulosclerosis was removed at time of trnasplantation. Recipient kidney tissue and donor kidney tissue were simultaneously fixed for electron microscopy. Primary fixation was in phosphate buffered gluteraldehyde followed by infiltration in 20 and then 40% glycerol. The tissues were frozen in liquid Freon and finally in liquid nitrogen. Fracturing and replication of the etched surface was carried out in a Denton freeze-etch device. The etched surface was coated with platinum followed by carbon. These replicas were cleaned in a 50% solution of sodium hypochlorite and mounted on 400 mesh copper grids. They were examined in an Siemens Elmiskop IA. The pictures suggested that the diseased kidney had heavy deposits of an unknown substance which might account for its inoperative state at the time of surgery. Such deposits were not as apparent in light microscopy or in the standard fixation methods used for EM. This might have been due to some extraction process which removed such granular material in the dehydration steps.
A Superconducting Microscope
Authors: Worsham R. E. , Mann J. E. , Richardson E. G.
Published: June 2020

This superconducting microscope, Figure 1, was first operated in May, 1970. The column, which started life as a Siemens Elmiskop I, was modified by removing the objective and intermediate lenses, the specimen chamber, and the complete vacuum system. The large cryostat contains the objective lens and stage. They are attached to the bottom of the 7-liter helium vessel and are surrounded by two vapor-cooled radiation shields.

In the initial operational period 5-mm and 2-mm focal length objective lens pole pieces were used giving magnification up to 45000X. Without a stigmator and precision ground pole pieces, a resolution of about 50-100Å was achieved. The boil-off rate of the liquid helium was reduced to 0.2-0.3ℓ/hour after elimination of thermal oscillations in the cryostat. The calculated boil-off was 0.2ℓ/hour. No effect caused by mechanical or electrical instability was found. Both 4.2°K and 1.7-1.9°K operation were routine. Flux pump excitation and control of the lens were quite smooth, simple, and, apparently highly stable. Alignment of the objective lens proved quite awkward, however, with the long-thin epoxy glass posts used for supporting the lens.
Observability of Very Thick Specimen by Using Transmission Scanning Electron Microscope
Authors: Shibatomi K. , Yamanoto T. , Koike H.
Published: June 2020

In the observation of a thick specimen by means of a transmission electron microscope, the intensity of electrons passing through the objective lens aperture is greatly reduced. So that the image is almost invisible. In addition to this fact, it have been reported that a chromatic aberration causes the deterioration of the image contrast rather than that of the resolution. The scanning electron microscope is, however, capable of electrically amplifying the signal of the decreasing intensity, and also free from a chromatic aberration so that the deterioration of the image contrast due to the aberration can be prevented. The electrical improvement of the image quality can be carried out by using the fascionating features of the SEM, that is, the amplification of a weak in-put signal forming the image and the descriminating action of the heigh level signal of the background. This paper reports some of the experimental results about the thickness dependence of the observability and quality of the image in the case of the transmission SEM.
A Method of Extending Electron Microscope Filament Life
Authors: Thomas G. F.
Published: June 2020

One of the problems of electron microscopy is the short life of the electron source, or filament. Exchanging filaments frequently requires realignment and recalibration procedures which are time-consuming.

We have developed a simple “tempering” procedure which more than doubled the filament life in our instrument, an RCA EMU-3G electron microscope.

Early in the use of our microscope, we noted that during the initial phase of emission of a new filament, a physical dislocation of the filament from its original point of alignment occurred. We also noted that oxidized surface material on the filament decomposed and emitted as contaminants into the gun area. It was felt that if a preliminary heating under well-controlled conditions (gradual increase of electron flow in a clean atmosphere as in a vacuum evaporator) was applied to a filament, there would be a pre-functional reorientation of valence electrons.
Combined Scanning—Transmission and Electron Probe Analysis of the Mammalian Small Intestine
Authors: Tousimis A. J.
Published: June 2020

The fine structure of the epithelium lining of the small intestine has been extensively studied by transmission electron microscopy of ultrathin sections during the past two decades.Chemical identification of cellular components, visualized by this method, have been limited primarily to the physicochemical identification of isolated fractions. Biochemical reactions carried out on these components are utilized for the indirect localization of macromolecular species such as proteins, carbohydrates, lipids, nucleic acids, nucleoproteins and other. Similarly, ionic species-electrolytes, nucleic acids and other molecular species transported or utilized by and for cellular activity have been “localized” by indirect methods only.

Early electron probe microanalyses of biological tissues have been applied in the localization and measurement of structural components of the cell, mineral or inclusion and biological calcification studies. Measurement of organic molecules in situ is possible only on tissue sections that have been specifically reacted with chemicals that can be elementally differentiated from other cellular structures.
A Computational Method for Image Analysis of a Crystal Containing Defects
Authors: Tan T. Y. , Bell W. L.
Published: June 2020

Within the scope of column approximation, image analysis of crystals containing defects amounts to solving the set of linear differential equations for all appreciably excited Bragg beams:

(here all quantities have their usual definitions as in the literatures).
Laboratory Computer-Scanning Electron Microscope System
Authors: MacDonald N. C. , Waldrop J. R.
Published: June 2020

The use of large, remote computers in electron microscopy for picture processing is now quite common. In scanning electron microscopy the picture information is generated by electronically scanning the electron beam across the specimen and monitoring an electrical signal, and consequently the scanning electron microscope (SEM) lends itself quite easily to complete electronic control and signal processing by an on-line computer. A prototype on-line computer-SEM system was constructed at Berkeley using an IBM 1800 computer and a control console located at the SEM. The results obtained with this system clearly demonstrated the usefulness of this approach. In this paper we describe the use of a small laboratory computer to control the electron beam, to process the many different signals generated by the SEM, and to display the resulting information in the desired format. Although the system is capable of storing pictures and performing simple picture processing, its main advantage is that it allows one to perform unique experiments with the SEM, to correct and analyze the data during the experiment, and to store the information for future processing and display. An additional advantage of the system is that complex SEM experiments can be performed without the usual delay time and additional cost required for constructing new electronics for each experiment; it is this system flexibility that we wish to illustrate by the results presented below.