bluuebunny/crossref_metadata_2025 huggingface dataset:
Formation and Ultrastructure of the Collagen Fibril—Rubin Borasky
Authors: Borasky Rubin , Sturgeon David B.
Published: June 2020

Although much is known about the chemistry and molecular organization of collagens there is a gap in the knowledge concerning the characteristics of the collagen fibril precursors (CFPs) synthesized in the fibroblast and how they are assembled into fibrils in intercellular space. Studies on the amino acids distribution profiles and structural defects of collagen fibrils, supported by chemical analyses and the concept of “macranolecular micelles” as monomeric units of fibrous proteins, permits the formulation of the following hypothesis for the formation and structure of the collagen fibril.

The CFPs or basic subunits of collagens, synthesized in the fibroblast and discharged into intercellular space, have the following properties. They vary in kind according to their amino acid composition and primary structure. They have molecular weights ranging from about 20,000 to 40,000 and consist of from about 150 to more than 300 amino acid residues. Many CFPs are polar in that they have amino acid residues the side chains of which carry charge.
Fine Structure of the Integument of the Cryptocotyle Lingua Redia
Authors: Krupa P. L. , Bal A. K. , Cousineau G. H.
Published: June 2020

Recent electron microscope studies of trematode rediae have revealed microvilli projecting from the integument, presumably to facilitate exchange of materials between the parasite and the snail host. This report on the redia of Cryptocotyle lingua extends these observations and provides an additional basis for future biochemical studies of host-trematode relations. The rediae were removed from crushed snails (Littorina littorea), washed in filtered sea water, fixed in 5% glutaraldehyde-paraformaldehyde solution in sea water, postosmicated, and embedded in Epon in the usual manner.

Light microscopy shows that the apical surface of the redial body wall has numerous undulations or corrugations of varying dimensions and shapes (Fig. 1, arrow). As seen in the electron microscope, many cytoplasmic projections or microvilli stem perpendicularly from these crests and valleys (Figs. 2,3). In tangential sections of the redial surface (Fig. 4), the microvilli appear as thin, flat structures or spatulae, rather than as cylindrical, digitiform projections. The expanded surface of some microvilli is also suggested in sagittal- sectioned rediae (Fig. 2).
Extralysosomal Destruction of Disrupted Bacterial Cells
Authors: Roth Ivan L.
Published: June 2020

It has been well established that the process of phagocytosis involves the enclosure of the phagocytized entity in a membrane limited vacuole called a phagocytic vacuole or phagosome.

In studying the ultrastructural aspects of Bacillus anthracis (anthrax) infections in mouse spleen, it has been found that the phagosome membrane is present around avirulent (non-capsulated) anthrax cells as shown in Figure 1 (M). However, the phagosome membrane has never been seen around virulent (capsulated) anthrax bacilli. This absence of the phagosome membrane around virulent cells might be due to the exotoxin produced by Bacillus anthracis. However, the phagosome membrane is absent even around virulent anthrax bacilli which have been killed by autoclaving (Fig. 2). Perhaps the destruction of the phagosome membrane is due to the surface character of the capsule.
Four Stage E.M. for Phase Contrast and Strioscopic Microscopy
Authors: Johnson H. M. , Parsons D. F.
Published: June 2020

Phase contrast electron microscopy should allow visualization of unstained biological structures. In an attempt to achieve this, we have modified a Siemens Elmiskop la microscope, in a way similar to that described by Faget, et al. (Proc. Fifth Int. Congr. Electron Microscopy, Philad., 1962, Abstract A-7). A number of phase contrast and strioscopic arrangements can be tested. A section consisting of phase plate chamber and additional intermediate lens (I2) was added to the column between the standard intermediate lens (I1) and the projector lens (Fig. 1). I1 was set, so as to project the back focal plane of the objective to the level of the phase plate holder (Fig. 2). I2 supplied final magnifications from 1,000 x to 80,000 x. Resolution was better than 15 Å. Two stigmators were used, one in the objective back focal plane and one in the plane of the phase plate. The source consisted of either a hairpin- or point- filament to allow variable coherence of illumination.
The Hitachi Model HS-8 Electron Microscope
Authors: Akabori H. , Nishiwaki K. , Yoneta K.
Published: June 2020

By improving the predecessor Model HS- 7 electron microscope for the purpose of easier operation, we have recently completed new Model HS-8 electron microscope featuring higher performance and ease of operation.
Electron Microscopy: The High Voltage Approach
Authors: Hart Raymond K.
Published: June 2020

In recent years there has been considerable interest in microscopes which operate at accelerating potentials well above the now conventional level of 100 kV. The use of these high voltage instruments in both biological and physical research offers substantial advantages over what can be realized with their lower voltage counterparts.

There are three aspects to very-high voltage microscopy that make it inviting: these are the presently demonstrated or expected improvements in image contrast, resolution and the thickness of specimens that can be viewed.
Mechanical Design of the One Million Volt U.S. Steel Microscope Column
Authors: Fairbanks J. R.
Published: June 2020

A unitized frame construction is employed as structural support for the one million volt column components. In this way alignment between the high voltage accelerator and the objective lens is maintained, and parallelism between all optical elements is held while permitting manual traverse of the other lenses. The frame, a 700 lb., type 304 stainless casting is suspended from a reference plate, forty inches in diameter by two inches thick. The reference plate is supported by an arched tripod with legs set in a concrete slab isolated from the building proper. (Figure 1) An expandable vacuum seal is located in each of the five shelves of the frame, providing a vacuum seal when expanded and clearance for lens removal when retracted.
Fractography of 6AL-4V Titanium Alloy Failed by Stress Corrosion in Various Environments
Authors: Thomas Gordon , Anderson W. C.
Published: June 2020

Fractures of 6Al-4V titanium alloy failed under stress in various environments are sufficiently characteristic to allow the fractographer to identify the specific environment involved. These environments include exposure to methanol, nitrogen tetroxide, hot sodium chloride, and hydrogen gas. The specimens were sheet stock in STA condition which were bend-loaded in a fixture to maximum stresses varying from 85,000 to 110,000 psi.
Oxidation of HCP Zirconium in the Electron Microscope
Authors: Bigelow W. C. , Hayes W. J. , Allard L. P. , Rowe Anne
Published: June 2020

A reaction stage designed in this laboratory for carrying out gas-solid reactions inside the electron micrpscope was described at the 24th Annual Meeting of the Electron Microscopy Society of America. Purified gas from an auxiliary line is brought into the microscope column and carried through a Teflon tube and slots in the walls of the stainless steel reaction chamber onto both sides of the thin film specimen. The image may be recorded directly on motion picture film as the reaction proceeds.

Earlier work using this stage was carried out on copper films showing wide stacking faults and surface terraces produced by annealing the metal before removal from the NaCl substrate; in subsequent treatments with oxygen the nucleation and growth characteristics of cuprous oxide were observed. Zirconium was selected for study in the high temperature reaction stage as an example of a metal having a hexagonal closest packed structure in which the effect of thermal anneal should be quite different from that in face-centered cubic materials.
Nucleation of Disorder in Fe3Al Alloys
Authors: Swann P. R. , Duff W. R. , Fisher R. M.
Published: June 2020

Recently we have investigated the phase equilibria and antiphase domain structures of Fe-Al alloys containing from 18 to 50 at.% Al by transmission electron microscopy and Mössbauer techniques. This study has revealed that none of the published phase diagrams are correct, although the one proposed by Rimlinger agrees most closely with our results to be published separately. In this paper observations by transmission electron microscopy relating to the nucleation of disorder in Fe-24% Al will be described. Figure 1 shows the structure after heating this alloy to 776.6°C and quenching. The white areas are B2 micro-domains corresponding to regions of disorder which form at the annealing temperature and re-order during the quench. By examining specimens heated in a temperature gradient of 2°C/cm it is possible to determine the effect of temperature on the disordering reaction very precisely. It was found that disorder begins at existing antiphase domain boundaries but that at a slightly higher temperature (1°C) it also occurs by homogeneous nucleation within the domains. A small (∼ .01°C) further increase in temperature caused these micro-domains to completely fill the specimen.
Clustering of Irradiation Produced Defects near Boundaries in Molybdenum
Authors: Mastel B. , Brimhall J. L. , Bierlein T. K.
Published: June 2020

The microstructures of molybdenum containing ∼10 ppm carbon irradiated at 60°C to a neutron fluence of 1 × 1019 n/cm2 (E < 1 MeV) and subsequently annealed at elevated temperatures were compared with microstructures of similar material irradiated at 600°C and subsequently annealed.

Small defect clusters 50Å in diameter form in molybdenum during irradiation at 60 °C. These clusters are uniformly distributed throughout the sample and are believed to be interstitial in character. During a two hour anneal at 575°C cluster density decreases uniformly and cluster size increases somewhat. After a two hour anneal at a sufficiently high temperature, 900°C, all clusters disappeared. Denuding of clusters adjacent to grain boundaries was not observed after any of the isochronal annealing treatments in temperature steps of 100°C.
Electron Microscopic and Optical Observations of Obsidian Hydration
Authors: Gibbon Donald L. , Michels Joseph W.
Published: June 2020

It has been shown that the rate of hydration of obsidian is directly related to the time that hydration has taken place. Thus artifacts made of obsidian exhibit a hydration rim of thickness directly related to the age of the artifact. Accurate determination of the age of obsidian artifacts depends on several factors: 1) the ability of the investigator to accurately measure the thickness of the hydration rim, commonly in the range 1 to 10 microns; 2) the variance of the thickness of the hydration rim over the sample surface; 3) the influence of weathering conditions on the hydration rate. The third point is adequately treated elsewhere. The first two points are the object of this investigation.
Direct Observation of Heat Exchanger Deposits by Cross Sectioning
Authors: Anderson R. W. , Senecal D. L.
Published: June 2020

A problem was presented to observe the packing densities of deposits of sub-micron corrosion product particles. The deposits were 5-100 mils thick and had formed on the inside surfaces of 3/8 inch diameter Zircaloy-2 heat exchanger tubes. The particles were iron oxides deposited from flowing water and consequently were only weakly bonded. Particular care was required during handling to preserve the original formations of the deposits. The specimen preparation method described below allowed direct observation of cross sections of the deposit layers by transmission electron microscopy.

The specimens were short sections of the tubes (about 3 inches long) that were carefully cut from the systems. The insides of the tube sections were first coated with a thin layer of a fluid epoxy resin by dipping. This coating served to impregnate the deposit layer as well as to protect the layer if subsequent handling were required.
An Attack on the Contamination Problem in the Electron Microscope
Authors: Kelsch J. J. , Holtz A.
Published: June 2020

A simple solution to the serious problem of specimen contamination in the electron microscope is presented. This is accomplished by the introduction of clean helium into the vacuum exactly at the specimen position. The local pressure gradient thus established inhibits the migration of hydrocarbon molecules to the specimen surface. The high ionization potential of He permits the use of relatively large volumes of the gas, without interfering with gun stability. The contamination rate is reduced on metal samples by a factor of 10.
Application of Scanning Electron Microscopy to Medical Research
Authors: Hutchison J. D.
Published: June 2020

When the transmission electron microscope was commercially introduced a few years ago, it was heralded as one of the most significant aids to medical research of the century. It continues to occupy that niche; however, the scanning electron microscope is gaining rapidly in relative importance as it fills the gap between conventional optical microscopy and transmission electron microscopy.

IBM Boulder is conducting three major programs in cooperation with the Colorado School of Medicine. These are the study of the mechanism of failure of the prosthetic heart valve, the study of the ultrastructure of lung tissue, and the definition of the function of the cilia of the ventricular ependyma of the brain.
“Interpretation of Micrographs from a Scanning Electron Microscope”
Authors: Eichen E. , Fitchmun D. R. , Sefton L. R.
Published: June 2020

In the past two years, there has been a great increase in interest in the scanning electron microscope as a research tool. Coupled with this has been a large increase in the number of instruments being used throughout the world. The reasons for this popularity stems from the unique abilities of this form of in strumentation which include: (a) a large depth of field which allows one to view a very rough surface; (b) a minimal requirement of specimen preparation; and (c) its ability to make use of voltage contrast in the study of semiconductors.
Scanning and Transmission Electron Microscopy of Human Red Blood Cells
Authors: Tousimis A.J. , Padden T.R.
Published: June 2020

The size, shape and surface morphology of human erythrocytes (RBC) were examined by scanning electron microscopy (SEM), of the fixed material directly and by transmission electron microscopy (TEM) of surface replicas to compare the relative merits of these two observational procedures for this type specimen.

A sample of human blood was fixed in glutaraldehyde and washed in distilled water by centrifugation. The washed RBC's were spread on freshly cleaved mica and on aluminum coated microscope slides and then air dried at room temperature. The SEM specimens were rotary coated with 150Å of 60:40- gold:palladium alloy in a vacuum evaporator using a new combination spinning and tilting device. The TEM specimens were preshadowed with platinum and then rotary coated with carbon in the same device. After stripping the RBC-Pt-C composite film, the RBC's were dissolved in 2.5N HNO3 followed by 0.2N NaOH leaving the preshadowed surface replicas showing positive topography.
Performance Characteristics of the Nondispersive X-ray Spectrometer
Authors: Russ J. C.
Published: June 2020

With the relatively recent introduction of nondispersive (or energy dispersive) xray spectrometers for the scanning electron microscope, there has been much interest on the part of users because this type spectrometer lends itself well to the scanning microscope and consequently there is brisk competition among the various suppliers of these devices. It is necessary for the user to have some working understanding of this type spectrometer as it is quite different from the conventional dispersive spectrometer commonly used on microprobes.
Observation of Biological Specimens with a High Voltage Electron Microscope
Authors: Nagata F. , Hama K.
Published: June 2020

Advantageous merits of a high voltage electron microscope over conventional ones are believed to be as follows. Thicker specimens can be observed easily as a result of greater penetration power. Higher resolution in images is expected to be attained in consequence of greater penetration power and less aberration effects. Specimens are less damaged from the illuminating beam.
Design and Application of a High Voltage Transmission Scanning Electron Microscope
Authors: Cowley J. M. , Strojnik A.
Published: June 2020

A transmission scanning electron microscope operating at voltages up to 600 kV has been built in this laboratory. Initial tests of the performance have been encouraging although the optimum performance has not yet been achieved. Developments and modifications of the instrument are now in progress in order to extend its range of applications and improve its output.

The high voltage power supply and electron accelerator have been described previously. A combination of insulating oil and solid dielectric i s used to decrease leakage. This allows the high voltage unit to be compact, highly stable and inexpensive. It has proved to be reliable and trouble-free in operation.
Recent U.S. Steel Developments in High Voltage Microscopy
Authors: Fisher R.M. , Thomas L.E. , Lally J.S.
Published: June 2020

Since its inauguration, the U.S.S. MVEM has been applied to fundamental studies of the nature of electron radiation damage and the mechanisms of strengthening, precipitation and recrystallization as well as industrial and bio-medical applications. In addition, considerable effort has been expended in optimizing the performance of the microscope and in analyzing the characteristic features of image contrast in high voltage electron micrographs. A brief review of the salient features of these studies of general interest to electron microscopists will be presented.
Materials for Electron Beam Information Storage
Authors: Speliotis D. E.
Published: June 2020

The interaction of electron beams with a large variety of materials for information storage has been the subject of numerous proposals and studies in the recent literature. The materials range from photographic to thermoplastic and magnetic, and the interactions with the electron beam for writing and reading the information utilize the energy, or the current, or even the magnetic field associated with the electron beam.
The Theoretical Contrast in Scanning and Conventional High Resolution Microscopes
Authors: Zeitler E. , Thomson M. G. R.
Published: June 2020

In the formation of an image each small volume element of the object is correlated to an areal element in the image. The structure or detail of the object is represented by changes in intensity from element to element, and this variation of intensity (contrast) is determined by the interaction of the electrons with the specimen, and by the optical processing of the information-carrying electrons. Both conventional and scanning transmission electron microscopes form images which may be considered in this way, but the mechanism of image construction is very different in the two cases. Although the electron-object interaction is the same, the optical treatment differs.
Informational Analysis of Performance for a High Resolution Electron Microscore
Authors: Welton T. A.
Published: June 2020

Conventional performance criteria for transmission electron microscopes generally involve statements of the spatial resolution permitted by the aberrations of the system and the contrast level permitted by the nature of the object under study. An attempt has been made to formulate a more meaningful set of criteria, which take into account all the essential phenomena encountered in the study by transmission electron microscopy of biologically important macromoleeules. These phenomena include beam coherence and energy spread, interaction of beam with sample, defocus and primary and secondary spherical aberration, diffraction by the objective aperture and retardation by a possible phase shift film in the back focal plane, multiple scattering of electrons in the detecting emulsion, and noise arising from electron and silver grain statistics.
Clinical Electron Microscopy of the Glomerulus in Human Renal Disease
Authors: Weimer R. V. , Rupe C. E. , Watson J. H. L.
Published: June 2020

Electron microscopy of the glomerulus in human renal disease has yielded much data of clinical significance. Two predominant classifications of glomerular pathology are met: proliferative and membranous transformations. The latter is further divisible into those with or without deposits, usually associated with the capillary basement membrane BM. A precise ultrastructural classification would be a significant contribution to diagnosis. Seven of the classical glomerular lesions will be presented. The figures represent four of them. Three others will also be given in the demonstration viz. "Systemic" Lupus Erythematosus, Amyloidosis and The Nephrotic Syndrome.
Part III: Ultrastructural Observations on Metastatic Nodules of Human Breast Cancer
Authors: Swedo John L. , Talley R. W. , Watson John H. L.
Published: June 2020

In continuation of the previous two reports describing the ultrastructure of metastatic nodules of human breast cancer which respond favorably to varied hormonal therapy, this report is confirmative and supplementary to the previous two presentations. Specimen preparation was as reported for the earlier reports with the exception that section contrasting was accomplished with combinations of uranyl acetate and lead citrate rather than lead hydroxide. Markers for all micrographs equal 0.25 µ.
Ultrastructural Features of Native Collagen Fibrils
Authors: Pease Daniel C. , Bouteille Michel
Published: June 2020

Unfixed collagen of rat aortic adventitia was dehydrated with ethylene glycol at appropriate speed and at room temperature. Thin sections then were examined after various embedments and staining procedures. During hydroxypropyl methacrylate (HPM) embedment, and to a lesser extent during Vestopal embedment, fibrillar swelling tended to occur which resulted in the separation of more or less isolated cords and septa of material (Figs. 3a and b). This did not occur in Epon. Although the dissociation was clearly an artifact, it provided new insights into native fibrillar structure.
Demonstration of the Use of Tape-Recorded Information from a High Vacuum Electron Microscope
Authors: Hartman Richard E. , Hartman Roberta S. , Ramos Peter L.
Published: June 2020

We have long felt that some form of electronic information retrieval would be more desirable than conventional photographic methods in a high vacuum electron microscope for various reasons. The most obvious of these is the fact that with electronic data retrieval the major source of gas load is removed from the instrument. An equally important reason is that if any subsequent analysis of the data is to be made, a continuous record on magnetic tape gives a much larger quantity of data and gives it in a form far more satisfactory for subsequent processing.
Paramyxovirus-like Structures in Lupus and Dermatomyositis
Authors: Hashimoto Ken
Published: June 2020

Paramyxovirus-like structures in so-called collagen disease have been reported in polymyositis and systemic lupus erythematosus. The identical structure was found in the present study in the skin lesions of discoid lupus erythematosus and dermatomyositis; these two are also called collagen diseases. This report deals with detailed ultrastructure and some aspects of the mode of formation of this structure as they are seen in the skin lesions of discoid lupus and dermatomyositis.
Poxvirion Spectra
Authors: Sharp D. G. , Mcguire Peter
Published: June 2020

The individual virus particles that comprise the entire population released from a culture of infected cells were once thought to be highly uniform in physical characteristics. Present concepts of virus reproduction have provided no good reason to think otherwise nor have excellent recent electron micrographs of highly purified preparations of vaccinia virus shown obvious physical heterogeneity. Nevertheless a considerable range of heterogeneity does exist, both physical and biological, as shown by a combination of zonal centrifugation, electron microscopy and plaque titration.
Intracellular Structures in Negatively Stained Bacteria
Authors: Abram Dinah
Published: June 2020

Intact bacteria have been examined after negative staining with five compounds commonly used to reveal ultrastructure in biological material. Escherichia coli, Proteus vulgaris, Spirillum serpens, Bacillus pumilus, Bacillus circulans and Bacillus anthracis were employed. Exponential phase cells on agar containing 1%. trypticase and 0.2% yeast extract were washed off with distilled water to yield suspensions containing 109 to 1011 cells/ml. Aqueous solutions of potassium phosphotungstate, pH 6.8 to 7.2 (KPT), lithium tungstate, pH 7.1 (LiT), sodium tungstate, pH 7.1 (NaT), ammonium molibdate, pH 7.0 (AM) and urnyl acetate EDTA complex, pH 6.8 (UA/EDTA) were used to stain the cells.
Structure of the Secretory Portion of Calliphora Salivary Glands
Authors: Oschman J. L. , Berridge M.J.
Published: June 2020

There has been much interest in the morphogenesis of the protein secretions of insect salivary glands. However, little is known about how the watery component of the saliva is produced. We have studied this aspect of secretion in Calliphora erythrocephala, an insect which apparently produces only one salivary enzyme, amylase. In vitro preparations of the abdominal portions of the paired salivary glands of this insect secrete fluid slowly. Addition of 5-hydroxytryptamine (1 x 10-9 M) to the bathing medium causes a 60-fold increase in the secretion rate. The secreted fluid is high in K and low in Na compared to the bathing medium.
Electron Microscopic Observations of L-Lactate Dehydrogenase Crystals
Authors: Labaw L. W.
Published: June 2020

Dogfish muscle lactate dehydrogenase (LDH) has been shown by M. G. Rossmann and his associates at Purdue University to crystallize in space group 1422 with the tetramolecular tetragonal unit cell dimensions of a = b = 103.5, c = 155.1 Å. They have found the roughly cubic molecule to contain four approximately rectangular-prism-shaped subunits arranged in 222 symmetry. The molecular weight (140,000) and unit cell size suggest that these crystals might profitably be studied with the electron microscope for comparison with the x-ray information. Suitably sized crystals grown by Rossmann's group in about 40% saturated ammonium sulfate were either cross-linked with gluteraldehyde and embedded in Maraglas for sectioning or washed in 50% saturated ammonium sulfate preparatory to making the shadowed carbon replicas.
Changes in Tissue Organization which Precede the Onset of Cell Division in the Cultured Rabbit Lens
Authors: Unakar N. J. , Reddan J. R. , Harding C. V. , Bell R. M.
Published: June 2020

Mitosis in the adult lens is normally confined to a region of the epithelium referred to as the germinative zone. Cells of the central epithelium are normally devoid of proliferative activity but can be induced to undergo a parasynchronous burst of DNA synthesis and mitosis when cultured under suitable conditions. It would seem that the maintenance of the "blocked" mitotic state and the release of the cells from this state must have a basis in the overall organization of the tissue. If this is true, triggering of mitosis might be reflected in the initial fine structural changes which precede cell division in the cultured lens.
Effect of Cystine on Fertilization Membrane Development
Authors: Inoué S. , Hardy J.P. , Cousineau G.H. , Bal A.K.
Published: June 2020

The fertilization membrane of sea urchin embryos are formed by the elevation of the vitelline membrane to which cortical material fuses. As was shown by Monroy the addition of cystine does not prevent either the elevation of the vitelline membrane or the adherence of the cortical material, but the cortical material does not fuse with the vitelline membrane.
Effects of Puromycin on Fat Absorption in the Rat Intestinal Epithelial Cell
Authors: Friedman Harold , Cardell Robert R.
Published: June 2020

The intestinal absorptive cells of a normal rat begin to accumulate lipid fifteen minutes after intubation of corn oil. This lipid is found within vesicles or tubules of smooth endoplasmic reticulum (SER) in the apical cytoplasm of the cell. It is within the ER that the lipid is resynthesized from free fatty acids and 2-monoqlycerides into triglycerides. With the passage of time, the vacuoles and droplets of triglyceride increase in size and migrate to the Golgi apparatus. Here the droplets are condensed into larger ones and they may undergo modifications reauired for transport from the cell. Then the lipid droplets, known as chylomicra migrate via Golgi vacuoles to the lateral cell border, the vacuole membrane fuses with the plasma membrane and the lipid is discharged into the intercellular space.
Comparative Ultrastructure of Freeze-Cleaved and Thin-Sectioned Membranes
Authors: Weinstein Ronald S. , McNutt N. Scott
Published: June 2020

The structure of biomembranes may now be studied at relatively high resolution using two vastly different electron microscopic preparative techniques. One utilizes thin sections of chemically fixed, dehydrated, and plastic embedded tissue while the other, freeze-cleaving, allows for the examination of partially hydrated tissues which are physically fixed by freezing. Each technique introduces certain artifacts, some of which have been investigated and others that are ill-defined. Although there is a minor degree of overlap between the artifacts of the two techniques, most of the artifacts are unique to one technique or the other. Therefore, comparison of the electron microscopic images of membranes produced with the two techniques may shed light on both technical artifacts and on the true structure of membranes. We have carried out comparative studies on a number of different kinds of membranes, two examples of which are briefly described.
Bacteria in the Epithelium of Jejunum in Whipple's Disease
Authors: Watson John H. L. , Haubrich William S.
Published: June 2020

Bacteria, both free and phagocytized within macrophages, have been reported by many investigators within the lamina propria of the human intestine in Whipple's disease, but not in any other locations within the intestinal wall. The only exception to this has been the description of certain rounded, polymembranous structures with an electron-dense interior (differentially stained by uranyl acetate), within lysosome-like bodies in the epithelial cells. These structures have been discovered frequently in the present work, and are exampled at the arrows in the insert to Fig. A. They are found in both longitudinal and cross section, and have all the morphological and size properties identical with the bacteria found so plentifully in the lamina propria. In an effort to find other occurrences of bacterial bodies outside the lamina propria, specimens of 10-year old, methacrylate-embedded tissue were reexamined in greater detail.
Morphological and Immunological Studies on Cat Embryo Cells in Vitro Treated with Cell-Free Filtrate of Spontaneous Feline Lymphoma
Authors: Maruyama K. , Dmochowski L. , Swearingen G. R. , Lewis M.
Published: June 2020

Following the demonstration by mixed hemadsorption reaction of a common antigen in cell cultures containing type C particles and derived from leukemic animals of different species (K. Maruyama and L. Dmochowski: Texas Rpts. Biol. & Med., 1969, in press), the present study was undertaken to ascertain relationship of the common antigen with type C virus particle infection.
Surface Structures in Budding Cells of Torulopsis Giabrata
Authors: Edwards Mercedes R. , Holt Stanley
Published: June 2020

The fine structure of Saccharomyces cerevisiae has been investigated extensively while relatively little work has been done on other yeast species. The present study compares Torulopsis glabrata with S. cerevisiae. Cells in the logarithmic phase of growth were (a) quickly frozen in Freon 22, cut and replicated in a Balzer's apparatus according to Moor's technique; (b) fixed in glutaraldehyde-osmium, dehydrated, and embedded by conventional methods. Only the illustrations of the surface structures are presented.
Uranyl Acetate as a Stain and a Fixative for Heart Tissue
Authors: Hayat M. A.
Published: June 2020

Lead salts show affinity for a wide range of cellular structures and they increase general contrast much more intensely than any other known electron stain. However, lead stains do not show a strong affinity for nucleic acids, especially DNA. Since uranyl salts exhibit special affinity for nucleic acids, double staining of sections with uranyl acetate followed by lead acetate has become quite popular. Uranyl acetate is also an excellent fixative provided the tissue is treated with this reagent prior to dehydration. After double fixation with glutaraldehyde and osmium tetroxide, uranyl acetate treatment prior to dehydration markedly improves the preservation of all cell components especially that of nucleic acids, ground proteins, myofibril including Z bands, and mitochondrial matrix. Thus, when employed prior to dehydration, uranyl acetate acts not only as a stain but also as a general fixative for both nucleic acids and proteins (Hayat, 1969). Uranyl acetate is so easy to apply to both the tissue block and the sections that there seems no reason for not routinely using it for general staining. In the present study, tissues were exposed to uranyl acetate twice. The details of the method used are given below.
Strioscopic Dark Field Imaging with the AEI EM801S
Authors: Brookes K. A. , Hilditch D. H. , Chescoe D.
Published: June 2020

Insufficient contrast is generally the main limitation in resolving fine detail in biological specimens. Various preparation techniques such as staining and shadowing have been devised to improve image contrast, but these usually result in loss of resolution. It is therefore advantageous to be able to increase the contrast in the microscope image without recourse to special preparation techniques. The two techniques commonly used to gain such an improvement are Dark Field Imaging and Objective Defocus, the latter suffering the disadvantage of image interpretation due to the filtering of specific frequencies depending upon the amount of defocus and the spherical aberration of the lens. Dark field images can be formed by various techniques, displaced objective aperture, tilted illumination, contrast stop objective aperture and annular condenser aperture, the latter two collectively termed strioscopy. Since biological specimens are predominately amorphous thus giving only diffuse scattering with a few ring maxima and no discrete reflections, a strioscopic technique is preferred.
Computer Control of Energy Analysis in an Electron Microscope
Authors: Batson P. E. , Silcox J. , Vincent R.
Published: June 2020

Recent experiments have shown that, for suitable alloy systems (Al-Cu, Al-Mg), it is possible to detect changes in composition ∼ 1 atomic wt. % with a spatial resolution 10nm, by measuring shifts in the energy loss spectrum of electrons transmitted through a specimen in an electron microscope. The sensitivity and accuracy of the technique for microanalysis is limited by several factors: (i) the energy-loss spectrum is recorded photographically and then traced on a photodensitometer; the resulting curve is smoothed by hand and the data points are transferred to a computer; (ii) since both voltage and intensity scales are non-linear at this stage, they are adjusted by reference to calibration plates; (iii) even for a monochromatic incident beam, the half-peak full width of the 15 eV plasmon loss in Al is 1 eV; for Al-Mg alloys a composition change of 1% corresponds to a shift in the plasmon peak of 0.055 eV and so curve-fitting techniques must be applied to the corrected data.
High Resolution Goniometer Stage for Electron Microscope
Authors: Mikaziri A. , Ohomori S. , Yamamoto T.
Published: June 2020

The performance of a goniometer stage to an electron microscope may be evaluated from several view points, such as operational easy, stability and resolving power. Stability is the fundamental, however. As is often experienced, the incorporation of a specimen tilting mechanism into the specimen chamber causes a functional unstability of the instrument and also causes inconvenience in the design of the objective lens. The top entry goniometer stage has an advantage in mechanical and thermal stability, since the specimen and specimen shifting stage are symmetrically supported around the optical axis. This supporting system is the main difference from that of the side entry goniometer stage. In the latter, the vibration and thermal drift of the specimen is unavoidable, in principle, due to an unbalanced specimen support.

We have recently developed a top entry goniometer for the JEM-100B Electron Microscope, taking these points into account to meet the demand for high resolving power: this goniometer is of double tilt type, permitting each axis to tilt by ±30° and enabling the specimen to tilt around some composite tilting axis by ±40°.
Electron Image Analysis
Authors: Gibbard D. W. , Crawley J. A. , Cowham M. J.
Published: June 2020

The history of automatic image analysis is a short one, the techniques being limited until recent years due to the “state of the art” of technology in electronics. A new third generation image analysis machine, the Quantimet 720 was introduced in 1969 designed with a modular construction for application to many fields of interest. It was the first equipment of its type to depart from T.V. standards to scan standards required for optimising the conflicting requirements of high resolution, high speed and high signal to noise ratio. It features high resolution and digital circuitry for accuracy and repeatability and a large and growing range of modules for high computing power. It has also been applied to a wide range of image producing devices including light microscopes, epidiascope (for analysis of photo-micrographs), transmission and scanning electron microscopes.
Direct Observations of Twinning Dislocations in Iron Single Crystals
Authors: Ogawa Keiichi , Takeuchi Tomoyuki
Published: June 2020

Experimental confirmations so far obtained of twinning dislocations in bcc metals have been limited to the observation of the phase change in the stacking fault fringe contrast. In the present experiments, twinning dislocations in iron crystals have been directly observed by their strain field contrast.

Deformation twins were introduced into iron single crystals (1.8x6 mm2 in cross section) by an impact compression along <110> at 78°K. The compressive strain given was about 4%. The twinned specimens were mechanically sliced nearly parallel to the twin boundary {112} by a slitting saw. After mechanical polishing by emery paper, these slices were chemically polished to remove the damaged surface layers. The final thinning was performed by both jet and electrolytic polishing.
Shock Hardened and Annealed Type 316 Stainless Steel
Authors: Gelles S. H.
Published: June 2020

The structure of shock hardened Type 316 stainless steel has been examined by transmission electron microscopy in a number of different conditions involving variations in shock pressure, temperature, and post-shock annealing in an effort to correlate changes in mechanical properties with structural changes. The samples for microscopy were prepared by careful slicing from 1/2-inch-thick shock-hardened plate, the plane of the slice being parallel to the shock wave propagation direction. This was followed by dimpling in a 60 percent H3PO4-40 percent H2SO4 bath at 125 °C, and electrolytic polishing to break-through in the same solution at 70 °C.

Increasing the shock wave pressure from 0 to 320 kbar at ambient temperature produced structures with increasing dislocation densities. At 80 kbar, the easily-resolvable dislocations were relatively straight and lay in arrays on{111} [-planes as shown in Figure 1. At the 320 kbar pressure level, twin-like features formed (Figure 2) and were accompanied by a fine dislocation structure consisting in part of a high concentration of dislocation loops.
Direct Observation of the Diffusionless β → β + ω Transformation in Titanium Alloys
Authors: Paton N. E. , de Fontaine D. , Williams J. C.
Published: June 2020

The electron microscope has been used to study the diffusionless β → β + ω transformation occurring in certain titanium alloys at low temperatures. Evidence for such a transformation was obtained by Cometto et al by means of x-ray diffraction and resistivity measurements on a Ti-Nb alloy. The present work shows that this type of transformation can occur in several Ti alloys of suitable composition, and some of the details of the transformation are elucidated by means of direct observation in the electron microscope.

Thin foils were examined in a Philips EM-300 electron microscope equipped with a uniaxial tilt, liquid nitrogen cooled, cold stage and a high resolution dark field device. Selected area electron diffraction was used to identify the phases present and the ω-phase was imaged in dark field by using a (101)ω reflection. Alloys were water quenched from 950°C, thinned, and mounted between copper grids to minimize temperature gradients in the foil.
Electron Diffraction Effects in Multi-Layered (Overlapping) Palladium Single-Crystal Films
Authors: Wong G. I. , Singh H. P. , Murr L. E.
Published: June 2020

Simple multiple diffraction effects dealing with scattered or re-entrant beams in single foils containing twins or crystalline phases giving rise to double diffraction are generally well known. In addition, multiple diffraction arising in two overlapping thin films such as a multiple vapor deposit or an oxide on a crystalline substrate or base film has been studied. There are very few, if any, studies which attempt to systematically describe the diffraction patterns arising from overlapped, rotated, and imperfect single and polycrystalline thin films. This study demonstrates the complicated electron diffraction patterns which can arise by multiple diffraction in laye redarrays of thin Pd films, and describes the origins of some of the observed reflections.
Nucleation and Epitaxial Growth of Vapor-Deposited Films: Electron Transmission and Field-Ion Microscopy Studies
Authors: Murr L. E. , Inal O. T. , Singh H. P.
Published: June 2020

Current knowledge of the growth and structure of vapor-deposited thin films is based primarily upon experimental evidence obtained by electron diffraction and electron transmission microscopy. While a considerable body of information has been amassed, our understanding of nucleation and the occurrence of epitaxy is unclear. This disclarity arises in part because nucleation theories attempt to apply macroscopic (bulk) thermodynamic properties to small atomic aggregates on free surfaces, and because the sizes of so-called critical nuclei are deduced from extrapolations of experimental data involving observations of clusters in the electron microscope; having minimum sizes orders of magnitude larger. Clearly a fundamental understanding of nucleation and epitaxy can only be obtained by direct observations of the nature and orientation of nuclei, or of the atomic nature of the initial few atom layers of a deposit on a substrate. A potential technique for accomplishing these ends involves field-ion microscopy. This paper describes some field-ion microscope (FIM) studies of vapor-deposited Pt.
Nucleation and Growth Characteristics of Thin Metal Films
Authors: Singh H. P. , Murr L. E.
Published: June 2020

This paper reports observations of nucleation and growth characteristics of thin metal films vapor deposited onto heated sodium chloride substrates. An attempt is made to explain the differences in nucleation and growth characteristics on the basis of classical nucleation theory.

Thin metal films were prepared by vapor deposition onto heated NaCl (001) substrates in a commercial vacuum unit using a constant evaporation rate of approximately 1000 Å/sec. In the case of discontinuous thin films, approximately 200 Å of carbon was deposited for support. Samples for electron microscopy were prepared by standard techniques and were observed at 125 kV. Figs. 1(a) to (c) show a growth sequence of gold thin films characterized by 1) the formation of random, three dimensional, isolated nuclei at initial deposition, and their growth with further deposition predominantly by surface diffusion; 2) coalescence of these nuclei forming bigger islands; 3) the flattening of islands and formation of network structure : and 4) the filling up of these network structures with further deposition forming a continuous film.
The Clinical, Roentgenological and Morphological Effects of an Acute Exposure of Phosgene on the Lungs of Dogs
Authors: Bils R. F. , Diller W. F. , Huth F.
Published: June 2020

Phosgene still plays an important role as a toxic substance in the chemical industry. Thiess (1968) recently reported observations on numerous cases of phosgene poisoning. A serious difficulty in the clinical handling of phosgene poisoning cases is a relatively long latent period, up to 12 hours, with no obvious signs of severity. At about 12 hours heavy lung edema appears suddenly, however changes can be seen in routine X-rays taken after only a few hours' exposure (Diller et al., 1969). This study was undertaken to correlate these early changes seen by the roengenologist with morphological alterations in the lungs seen in the'light and electron microscopes.

Forty-two adult male and female Beagle dogs were selected for these exposure experiments. Treated animals were exposed to 94.5-107-5 ppm phosgene for 10 min. in a 15 m3 chamber. Roentgenograms were made of the thorax of each animal before and after exposure, up to 24 hrs.
Microanatomy of the Periplasm of Bacillus Licheniformis
Authors: Ghosh B.K.
Published: June 2020

Periplasm of bacteria is the space outside the permeability barrier of plasma membrane but enclosed by the cell wall. The contents of this special milieu exterior could be regulated by the plasma membrane from the internal, and by the cell wall from the external environment of the cell. Unlike the gram-negative organism, the presence of this space in gram-positive bacteria is still controversial because it cannot be clearly demonstrated. We have shown the importance of some periplasmic bodies in the secretion of penicillinase from Bacillus licheniformis.

In negatively stained specimens prepared by a modified technique (Figs. 1 and 2), periplasmic space (PS) contained two kinds of structures: (i) fibrils (F, 100 Å) running perpendicular to the cell wall from the protoplast and (ii) an array of vesicles of various sizes (V), which seem to have evaginated from the protoplast.
Intracytoplasmic Membrane Formation in the Hydrocarbon Oxidizing Bacterium, Micrococcus Cerificans
Authors: Kennedy R. S. , Spurlock Ben O. , Finnerty W. R.
Published: June 2020

Micrococcus cerificans is a gram negative, pleomorphic, coccoid bacterium capable of growth in complex or chemically defined media. The complex medium employed was nutrient broth-yeast extract (NBYE) while hydrocarbons constituted the sole source of carbon and energy in the chemically defined medium. Cells cultured in the above media were harvested in the late logarithmic growth phase and fixed according to the procedure of Kellenberger, et al. A variety of embedding techniques were used including those developed by Luft; Staubli; and Spurlock et al.

M cerificans cultured in the NBYE medium showed characteristic gram negative morphology including mesosomes. In the hydrocarbon grown cells an intracellular membrane system distinct from mesosomes was observed. Evidence suggests that these highly ordered membranous structures which appear as sheaths or bundles extending the width and/or length of the cells are continuous with the cytoplasmic membrane and are specific to hydrocarbon grown cells.