bluuebunny/crossref_metadata_2025 huggingface dataset:
Studies of Plastic Deformation Using High Voltage Microscopy
Authors: Wilsdorf H. G. F.
Published: June 2020

The first investigations of metals deformed plastically inside 100 kV electron microscopes provided the most comprehensive experimental evidence for the dynamic behavior of dislocations as predicted by theory. The fact that single dislocations were discernable during straining and that their path could be followed during additional strain increments, enabled us to see, for example, dislocations of the operating glide system to cross-slip around stationary dislocations, the formation of pile-ups, the dissolution of dislocation sub-boundaries, the cutting of single moving dislocations through dislocation, walls, and even the successive production of dislocations by Frank-Read sources. However, the thickness of the specimens was limited to a few thousand angstroms and dislocation patterns known to be present in deformed pure fee metals, such as “tangles,” were never observed in these thin films. Consequently it must be concluded from these experiments that the dislocation behavior of single dislocations corresponds to theoretical predictions but that the resulting patterns are not characteristic of plastic deformation in bulk specimens. Evidence is now accumulating that representative dislocation patterns can be produced in foils strained in high voltage electron microscopes (HVEM).
Human Interphase Nuclei; Dry Mass and Fiber Diameter
Authors: Golomb H. M. , Engler W. F. , Mikel U. , Bahr G. F.
Published: June 2020

Dry mass determinations of human male chromosomal homologues in each group (A through G) have previously been reported. In this report whole intact interphase nuclei present with the chromosome preparation are studied. The relationship of the dry mass of interphase nuclei to the total chromosomal complement dry mass (46, X, Y karyotype) and their respective fiber diameter is investigated.

Interphase nuclei were photographed quantitatively with a Siemens Elmiskop IA, and measured with the intergrating photometer (Carl Zeiss IPM-2). Absolute dry mass was determined using latex spheres as standards. Fibers of both interphase nuclei and individual metaphase chromosomes were photographed at 19.000X and their diameters measured on a Nikon profile projector.
The Observation of Channeling Patterns in Silicon Single Crystals at 200-500 kv
Authors: Geiss R. H. , Lawless K. R.
Published: June 2020

Transmission electron channeling patterns, the complement to the backscattered electron blocking patterns seen by Coates in the scanning electron microscope, have been observed in near perfect single crystals of silicon with the 500 kV electron microscope at the University of Virginia. Such channeling patterns, which are thought to be associated with the anomalous absorption and transmission of the Block waves describing the electrons inside a crystal, have all the characteristics of Kikuchi patterns and are but another example of the convergent beam phenomena first demonstrated by Kossel and Möllenstedt in 1939.

The difference between the work discussed here and that of Kossel and Möllenstedt and others using convergent beam techniques is that in our experiments the sample is placed near the center of a single field condenser-objective lens. The pre-field of the lens forms a convergent beam with an angular spread of approximately 10−2 radians and gives rise in the channeling pattern, while the post-field acts as an ordinary objective lens and enables defects in the sample to be imaged. The simultaneous action of these fields therefore yields images wherein defects are seen superimposed on the channeling pattern.
Microtubules and Microfilaments in the Glomeruli of Canine Renal Allografts
Authors: Lemanski Larry F. , Beggs John L. , Bertke Eldridge M.
Published: June 2020

The present-day concept of microtubules was originated when Ledbetter and Porter described them in the cytoplasm of plant cells. They concluded that microtubules were cytoplasmic structures of wide occurrence in cells of both plants and animals and that they were associated primarily with cytoplasmic movement. One earlier report of microtubules suggested a function in stabilization of cellular form as a cytoskeleton. De The demonstrated the presence of microtubules in several different animal cells, thus establishing these organelles as generic cytoplasmic structures of wide occurrence. Many subsequent investigations on a wide variety of plant and naimal cells have borne out the original ideas and have brought forth several new concepts regarding structure, function, and occurrence of these organelles. Microtubules have been described as being proteinaceous, having a clear center in cross section, being straight and up to 10μ long, having an outside diameter of about 250 Å, consisting of tubular subunits composing the wall of each tubule, and being most commonly present in the ectoplasm. Although seemingly evanescent, microtubules may be modified into more permanent structures such as fibrile of cilia or thick filaments of striated muscle. Often, microtubules are considered to be temporary structures capable of forming and depolymerizing spontaneously or by changes in pressure or temperature.
Interaction of Monocytes, Platelets, and Bacteria in Vitro
Authors: Clawson C. C. , White J. G. , Good R. A.
Published: June 2020

The injection of inert colloidal material or bacteria into the circulating blood of a living animal induces platelet aggregation and a fall in platelet count. This interaction of particulates with circulating platelets appears to have an intimate relationship with the subsequent clearance of the foreign particles from the circulation by the reticuloendothelial system Most previous investigations of this phenomenon have employed inert colloids in vivo. An in vitro system has been designed which allows close sequential evaluation of the interactions of living bacteria, platelets, serum factors and mononuclear phagocytes (monocytes).
Different Pathways of Food Transportation in the Intestinal Cells of Larvae and Adult Rana Pipiens
Authors: Giaquinta R. , Hayat M. A.
Published: June 2020

Although the ultrastructural changes in the intestinal epithelium during amphibian metamorphosis have been reported (Bonneville, 1963), little information is available on the pathways of food transportation in the intestinal epithelium of various metamorphic stages of Rana pipiens. This report describes two different pathways of food transportation in the intestinal epithelium of larvae and adult frog. Possible physiological significance of the proposed pathways has been discussed.

Tadpole and adult Rana pipiens were fed herbivorous and carnivorous diets respectively, and 48 hr after feeding, thve animals were dissected and segments of the small intestine were collected for electron microscopy. The tissue specimens were processed according to standard procedures (Giaquinta and Hayat, 1970; Hayat, 1970).
Fine Structural Alterations in Fallopian Tube Epithelium
Authors: Horbelt D. V. , Roberts D. K.
Published: June 2020

The epithelium of the uterus and fallopian tube undergo cyclic ultrastructural changes as the levels of feminine hormones fluctuate during the menstrual cycle. Other changes occur when pregnancy ensues. Marked alterations in the hormonal levels occur between term pregnancy and 72 hours post-partum. The ultrastructure of the fallopian tube reflects this change in hormone level. Specimens were obtained from human females at term pregnancy and 72 hours post-partum. The specimens were fixed with osmium tetroxide and embedded in Araldite. They were evaluated with a Philips 200 electron microscope.

Ciliated and secretory cells were considered from the distal and proximal end of each pregnant and post-partum female.
Langerhans Cell Granule as Phagocytic Organelle
Authors: Hashimoto Ken
Published: June 2020

In recent years the epidermal Langerhans cell has been considered to belong to histiocytic rather than melanocytic lineage. However, the functional significance of the Langerhans cell granule, which has also been called Bribeck's granule or racket body, has not been settled. In this study, 0.1 ml of horseradish peroxidase solution (25 mg in 1.0 ml normal saline) was injected intradermally into six sites on the back of a normal adult guinea pig. The injected sites were biopsied at 10, 30, 60, 120, 180 and 300 minutes and later at 22, 120 and 142 hours. The epidermis was minced with sharp razor blades into 1 mm blocks and fixed in 5% glutaraldehyde in 0.1 M cacodylate buffer (pH 7.2) for 3 hours at 4°C. After overnight rinse in the same buffer, tissue blocks were minced again into smaller pieces to facilitate the penetration of benzidine and hydrogen peroxide. Benzidine reaction was done according to the method of Schneeberger-Keeley and Karnowsky.
Changes in Myelin Ultrastructure Produced by a Series of Physical and Chemical Agents
Authors: Di Carlo Vincenzo
Published: June 2020

High-resolution electron microscopy of ultra-thin sections of fixed and plastic-embedded tissue shows that myelin consists essentially of an orderly aggregate of osmiophilic granules and osmiophobic globules. Frequently, granules and globules can be seen organized in hexagonal formations (diameter of about 90-120 A), which have an osmiophilic granule (diameter of about 30 A) in the center and six osmiophobic globules (diameter of about 40-45 A) around it. These formations are morphologically very similar to the “polyhedric-globular” (P-G) units (approx. 40-50 A high hexagonal prisms) which were described in the membrane of synaptic vesicles and mitochondria and in the plasma membranes of frog brain cortex as well as in the ribosomes of neurons of mammalian brain cortex. The P-G units were postulated to be an important, if not the exclusive, constituent of many biological membranes, which would be essentially a mosaic of such hexagonal prisms. Since ribosomes, which are believed to contain no lipid, also show the presence of P-G units in their structure, one wonders whether these units might possibly reflect mainly the presence of protein.
The Ultrastructure of the Trigger Hair in the Venus's Flytrap
Authors: Williams Mary E. , Mozingo Hugh N.
Published: June 2020

The Venus's Flytrap (Dionaea muscipula Ellis) has been the subject of several recent ultrastructural investigations. Only one recent investigation has dealt with the internal structure of the trigger hairs, and in this instance consisted only of a description of associated chloroplasts. Typically, lateral pressure on a trigger hair results in a flexure with a propagated action potential which rapidly results in leaf closure. Flexure occurs at a circumferential constriction near the top of podium supporting the main portion of the hair. These studies were undertaken in an attempt to learn the nature of the pressure transducer. Material was fixed in glutaraldehyde, post-fixed in osmium tetroxide and embedded in a mixture of DER736 and Epon 812. Sectioned material shows a complex internal structure with significant differences occurring between what appear to be three major zones of the podium. The distal area of short cells immediately above the constricted zone are poorly vacuolated, contain numerous mitochondria (M) densely packed with tubular cristae, small chloroplasts with a sparse lamellar system (Fig. B) and few or no apparent thylakoid stacks.
Electron Microscopy of the Developing Cotton Fiber
Authors: Berlin Jerry D. , Ramsey James C.
Published: June 2020

Cotton fibers are single cells that arise by virtue of elongation of certain cells in the outer epidermal layer of the outer integument of the cottonseed. Guard cells are present in this epidermal layer of the cottonseed, but the majority of the cells are cuboidal in nature (Fig. A). These cuboidal cells either elongate to become lint fibers or fuzz fibers or fail to elongate and simply remain as epidermal cells. Initiation of elongation of epidermal cells that ultimately become lint fibers occurs at anthesis. The mature lint fiber is a single cell having a diameter of some 20 micra and which is frequently over an inch in length.
Fine Structure of Interdental Cells in the Mouse Cochlea
Authors: Bruck Roberta M.
Published: June 2020

An unusual structure in the cochlea is the spiral limbus; this periosteal tissue consists of stellate fibroblasts and collagenous fibers embedded in a translucent ground substance. The collagenous fibers are arranged in vertical columns (the auditory teeth of Haschke). Between the auditory teeth are interdental furrows in which the interdental cells are situated. These epithelial cells supposedly secrete the tectorial membrane.

The fine structure of interdental cells in the rat was reported by Iurato (1962). Since the mouse appears to be different, a description of the fine structure of mouse interdental cells' is presented. Young adult C57BL/6J mice were perfused intervascularly with 1% paraformaldehyde/ 1.25% glutaraldehyde in .1M phosphate buffer (pH7.2-7.4). Intact cochlea were decalcified in .1M EDTA by the method of Baird (1967), postosmicated, dehydrated, and embedded in Araldite. Thin sections stained with uranyl acetate and lead citrate were examined in a Phillips EM-200 electron microscope.
Band Patterns in Chick Muscle at Short Sarcomere Length
Authors: Hagopian M. , Spiro D. , Yau P.
Published: June 2020

Glycerinated chick pectoral muscle was prepared for electron microscopy. Sarcomere lengths varied from 2.3 to 1.1μ reflecting various degrees of shortening. Over a sarcomere range of 2.3 to 1.3μ the thin actin filaments which measure 1.0μ and the thick myosin filaments which measure 1.5μ are constant in length (Fig. 1). At sarcomere lengths below 2μ the thin filaments penetrate through the center of the A band into the opposite halves of the sarcomere producing A contraction bands as previously described. In sarcomeres which measure 1.5 to 1.3μ additional contraction bands are noted adjacent to the Z lines. In longitudinal sections the array of filaments in the Z contraction band appears orderly (Fig. 2). It is our impression that these Z contraction bands result from penetration of the tapered lateral ends of the myosin filaments through the Z lines into the adjacent sarcomere rather than a crumpling of thick filaments as has been previously stated. Below 1.3μ in length the sarcomeres are disorganized, and it is not possible to define filament lengths.
Freeze-Etch Replication of the Microvasculature in Loose Connective Tissue of the Chick Embryo and Young Chick
Authors: Sanderson Margaret H. , Steamer S. Phyllis
Published: June 2020

The extra-embryonic membrane of the 3-day chick embryo and the mesentery of the 3-week chick, tissues of similar structure, were studied in conventional thin sections and freeze-etch replicas. The ultrastructure of the microvasculature and the surrounding interstitial region of the two tissues is compared.

In the 3-day chick embryo, there is no differentiation into vessel types. Small vessels in the area pellucida have a continuous endothelium (E) surrounded by processes of mesenchymal cells(M) (Fig. 1). The lumen(L) often contains erythrocytes (R). No continuous basement lamina(BL) is seen, and the interstitial spaces(IS) contain a few collagen fibers(C). In freeze-etch replicas, the endothelium is thin, with numerous cytoplasmic processes (Fig.2). The cytoplasmic matrix has some randomlyspaced particles, a few pinocytotic vesicles(PV), and other organelles. The interstitial space beneath the endothelium has a uniform vacuolar appearance. No basement lamina can be identified.
The Cartilaginous Nature of the Cervine Antler
Authors: Banks William J. , Neal Jennifer
Published: June 2020

The histomorphology and ossification process of the antler has been a subject of controversy. The exact nature of antler cartilage, based on light microscopic and limited histochemical analyses, has not been clarified. This report presents evidence that the ultrastructural features of antler progenitor cells and chondrocytes are similar to other cartilaginous systems which arise from reserve, undifferentiated cells.

An extensive fibrocellular cap covered the distal portion of the growing antler and was continuous with the typical periosteum of the antler shaft and frontal bone. This hyperplastic tissue (Fig. 1) was composed of fibroblastlike cells which contained large nuclei with 1 or 2 nucleoli (N). The cytoplasm contained numerous free ribosomes and polyribosomes, as well as granular endoplasmic reticulum (ER). The latter was tubular or vesicular; some exhibited dilations.
Studies on Leukemogenic and Sarcomagenic Viruses
Authors: Dmochowski Leon
Published: June 2020

Electron microscopy has proved to be an invaluable discipline in studies on the relationship of viruses to the origin of leukemia, sarcoma, and other types of tumors in animals and man. The successful cell-free transmission of leukemia and sarcoma in mice, rats, hamsters, and cats, interpreted as due to a virus or viruses, was proved to be due to a virus on the basis of electron microscope studies. These studies demonstrated that all the types of neoplasia in animals of the species examined are produced by a virus of certain characteristic morphological properties similar, if not identical, in the mode of development in all types of neoplasia in animals, as shown in Fig. 1.
Structural and Functional Changes in Altered and Reconstituted Cell Membranes
Authors: F. Trump Benjamin , U. Arstila Antti , J. Mergner Wolfgang
Published: June 2020

Important functional alterations involving membranes commonly occur in injured and diseased cells. Such alterations include, for example, changes in ion pumping activity, in energy transducing systems, in membrane permeability, and in protein synthesis. The structural and functional relationships of such changes are not clear; the extent to which the functional alterations can be reconstituted has hardly been explored. We have examined this general problem utilizing model membrane systems and comparing results obtained to studies utilizing intact cells. The systems utilized are 1) hepatic microsomes treated with phospholipase C; 2) hepatic microsomes subjected to lipid peroxidation using the NADPH dependent system described by Hochstein and Ernster; and 3) rat kidney mitochondria aged in vitro or isolated from ischemic rat kidneys.
Hepatic and Cardiac Changes in Protein-Deficient Rats
Authors: Zaki F. G.
Published: June 2020

A kwashiorker-like experimental model has been studied in young growing Holtzman rats fed protein-deficient diet (4% alpha-soy-protein) for 6-20 weeks. The animals lost weight during the first three weeks, but became adapted to the protein-deficient diet and maintained practically constant weight thereafter.

Hepatic lipid content progressively increased from 10% by the 6th week to about 20% after the 20th week. Deposition of hepatic lipid appeared initially in the periportal areas but gradually spread throughout the hepatic lobules. No fatty cysts nor fibrosis were encountered. Fatty degeneration was also noted in the cardiac muscle and the diaphragm.
The Morphology of the Rat Kidney Following Folic Acid Administration
Authors: Byrnes Aline , Ramos Elsa E. , Suzuki Minoru , Mayfield E.D.
Published: June 2020

Renal hypertrophy was induced in 100 g male rats by the injection of 250 mg folic acid (FA) dissolved in 0.3 M NaHCO3/kg body weight (i.v.). Preliminary studies of the biochemical alterations in ribonucleic acid (RNA) metabolism of the renal tissue have been reported recently (1). They are: RNA content and concentration, orotic acid-c14 incorporation into RNA and acid soluble nucleotide pool, intracellular localization of the newly synthesized RNA, and the specific activity of enzymes of the de novo pyrimidine biosynthesis pathway. The present report describes the light and electron microscopic observations in these animals. For light microscopy, kidney slices were fixed in formalin, embedded, sectioned, and stained with H & E and PAS.
The Cellular Origin in Atheromatous Lesion
Authors: Murad T. M. , Newman H. A. I. , Kern K. F.
Published: June 2020

The origin of lipid containing cells in atheromatous lesion has been disputed. Geer in his study on atheromatous lesions of rabbit aorta, suggested that the early lesion is composed mainly of lipid-laden macrophages and the later lesion has a mixed population of macrophages and smooth muscle cells. Parker on the other hand, was able to show evidence that the rabbit lesion is primarily composed of lipid-laden cells of smooth muscle origin. The above studies and many others were done on an intact lesion without any attempt of cellular isolation previous to their ultrastructural studies. Cell isolation procedures have been established for atherosclerotic lesions through collagenase and elastase digestion Therefore this procedure can be utilized to identify the cells involved in rabbit atheroma.
Ultrastructure of Fibroblast Cultures, Lymphocytes, and Liver in Mucopolysaccharidoses Types I, II, III, IV, and VI.
Authors: Hug George , Schubert William K. , Soukup Shirley
Published: June 2020

McKusick subdivided the syndrome of mucopolysaccharidoses into six types according to clinical, roentenographic, and genetic criteria and to the kind of mucopolysaccharide(s) excreted in the urine (1). Deficient activity of a lysosomal enzyme, (β-galactosidase, has recently been reported in types I, II and III of mucopolysaccharidoses as well as in generalized gangliosidosis (2). This apparent lack of disease specificity makes the enzymatic deficiency difficult to interpret. Nevertheless, the involvement of a lysosomal enzyme tends to characterize these disorders as lysosomal diseases.
Ultrastructural Changes in Patients With Heat Stroke
Authors: Minick O. T. , Kew M. C.
Published: June 2020

The effects of heat stroke on hepatic structure were studied in 32 Bantu patients who worked underground in the Transvaal and Orange Free State Gold Mines.

Judging from biochemical and morphologic findings, liver damage is an invariable complication of heat stroke. In the milder cases (90 per cent) raised enzyme levels, bromsulphalein retention, and increased prothrombin times were the most common abnormalities.
Neurovisceral Storage Disease of Childhood
Authors: Garcia Julio H. , Cox Janice V.
Published: June 2020

The majority of diseases in which there is central nervous system dysfunction, secondary to catabolic abnormalities (neuronal "storage" diseases), have been shown to result from enzymatic defects that lead to the intracellular accumulation of one or more of the following metabolites: sphingomyelin, gangliosides, cerebrosides and cerebroside-sulfuric acid esters (sulfatides).
Single Atom Contrast in a Scanning Microscope
Authors: Crewe V. , Langmore J. , Wall J. , Beer M.
Published: June 2020

The use of a scanning microscope offers unique opportunities in the way electrons penetrating a specimen can be Identified and collected.

In particular, a number Ne will be elastically scattered by virtue of a total cross-section σe which is proportional to Z4/3. The angular distribution is such that most electrons are scattered outside the Illuminating cone which is incident on the specimen. In addition, a number Ni will be inelastically scattered this time by very small angles with a total cross-section σi which is proportional to Z1/3.
Studies of DNA Using a 5 å Scanning Microscope
Authors: Wall J. , Langmore J.
Published: June 2020

One of the more important problems in electron microscopy has been the visualization of unstained DNA. Using the scanning microscope developed in the Crewe lab1 it is possible to see unstained DNA and to directly compare the observed contrast with that calculated from a simple incoherent scattering theory.

The electrons passing through a 5 Å spot on the specimen can be conveniently separated into three groups--elastically scattered, inelastically scattered and unscattered. These groups are separated in space and can be simultaneously counted by independent detectors. In this way each 5 Å point on a square raster is measured sequentially. Table I shows calculated and measured intensities for various salts of double-stranded DNA on a 30 Å thick carbon film.
Radiation Damage, Contrast and Statistics in High Resolution Biological Electron Microscopy
Authors: M. Glaeser Robert
Published: June 2020

It is well known that a large flux of electrons must pass through a specimen in order to obtain a high resolution image while a smaller particle flux is satisfactory for a low resolution image. The minimum particle flux that is required depends upon the contrast in the image and the signal-to-noise (S/N) ratio at which the data are considered acceptable. For a given S/N associated with statistical fluxtuations, the relationship between contrast and “counting statistics” is s131_eqn1, where C = contrast; r2 is the area of a picture element corresponding to the resolution, r; N is the number of electrons incident per unit area of the specimen; f is the fraction of electrons that contribute to formation of the image, relative to the total number of electrons incident upon the object.
The Energy Loss of 20 Kev Electrons in Biological Molecules
Authors: Crewe V. , Isaacson M. , Johnson D.
Published: June 2020

As part of a program to investigate the Interactions of fast electrons with thin specimens, we have measured the characteristic energy loss spectra of 20 kev electrons transmitted through thin films of various biological molecules. Such spectra are necessary In order to determine the potential of energy loss information as a contrast mechanism in high resolution transmission electron scanning microscopy.
Electron Beam Damage in Biological Molecules
Authors: Crewe A. V. , Isaacson M. , Johnson D.
Published: June 2020

In order to determine the potential of electron energy loss Information as a contrast mechanism in transmission scanning microscopy, as well as to better understand the interaction of electrons with the specimen in any electron microscope, more knowledge is needed concerning the damage produced in the specimen by the beam. This is especially true in biological specimens where the radiation damage is very significant, but not well understood. To investigate this problem, we have begun a series of experiments studying the effects of the passage of a ∼20 kv electron beam through thin films of important biological molecules.
Ultrastructure of Atypical Spermatozoa in Colcemid-Treated Chinese Hamsters
Authors: Brinkley B. R. , Rattner J. B. , Gay Marion
Published: June 2020

Colcemid, a derivative of colchicine, is well known for its capacity to inhibit microtubule formation in plant and animal cells. To determine the role of various microtubular systems such as the manchette, centrioles, and flagellar apparatus in mammalian spermiogenesis, adult male Chinese hamsters were injected daily with Colcemid at concentrations of from 6.5 x 10-5 M to 2.8 x 10-2 M. At various times following injections, the animals were sacrificed and testes and epidiymides were prepared for both light and electron microscopy.

Concentrations greater than 2.7 x 10-4 M generally were lethal to animals within a period of 24 hours to 9 days. At lesser concentrations, animals survived normally without apparent ill effects.
Ultrastructural Changes of Stromal Cells in the Hamster Uterus During Pseudopregnancy
Authors: Brinsfield T. H. , Clark M. V.
Published: June 2020

It is well known that the uterus is involved in regulating the lifespan of the corpus luteum in several species of farm and laboratory animals. Removal of the uterus during the luteal-phase of the estrous cycle or during particular days of pseudopregnancy extends corpus luteum lifespan to approximately that of gestation. These studies suggest that the uterus is in some way responsible for the normal regression of the corpus luteum. The purpose of the present study was to determine if ultrastructural changes could be detected in the endometrial stromal cells of the hamster uterus during that phase of pseudopregnancy in which the uterus influences the corpus luteum lifespan.
Crystalline Inclusions Associated With Virus
Authors: Pardo M. , Merkow L. P. , Henry C. , Slifkin M.
Published: June 2020

In a rare, benign hilar cell tumor of the ovary, many crystals (crystalloids) of Reinke were found within the cytoplasm or nucleus of neoplastic hilar cells. These crystals of Reinke (Fig. 1), by electron microscopy, displayed six hexagons surrounding one central hexagon in a transverse plane of section. The diameter across three hexagons of a mature crystal was approximately 90 my. In addition, immature or elementary tubular inclusions were also noted either in the nucleus or cytoplasm (Fig. 2), but not simultaneously in both. These immature inclusions in a longitudinal plane of section consisted of numerous elongated rods (Fig. 2). However, in a transverse plane, six microcylinders circumscribing one central microcylinder were evident and formed a “petals of a flower” or rosette pattern. The diameter of one rosette of an immatture inclusion was also approximately 90 mμ.
Polymerizable Glutaraldehyde-Urea Mixtures as Water-Soluble Embedding Media
Authors: G. Peterson Richard , C. Pease Daniel
Published: June 2020

Aldehyde-urea mixtures can be polymerized in the presence of substantial quantities of water. The components are highly polar. This provides an opportunity for preserving lipid structures in situ for ultrathin sectioning. Myelin retains its true periodicity (180Å) and integrity without osmication (1). Furthermore, the use of such embedding media permits superior preservation of highly hydrated structures, such as the glyco-calyx, which otherwise collapses.

We have been preparing resin mixtures by adding appropriate amounts of urea to either 50%. (Fisher Co.) or 70% (Ladd Co.) glutaraldehyde, adjusted as necessary to pH ≃ 6. The proportion is not critical, but a 1: 1 molar ratio which provides equal numbers of aldehyde and amide groups polymerizes satisfactorily.
The Third Dimension of Rheumatoid Arthritis
Authors: M. Riddle Jeanne , B. Bluhm Gilbert
Published: June 2020

Our application of scanning electron microscopy to the investigation of synovial membrane surface topography in humans has yielded new morphologic information. Samples of synovium removed from patients with advanced rheumatoid arthritis exhibited projecting villi such as those depicted in Fig. 1 as a prominent feature of their three-dimensional microarchi-tecture. In addition, localized areas of fibrin deposition, large parallel folds and focal irregular cavities were observed. Synovial lining cells were protuberant, increased in number and variable in size with many larger synoviocytes evident. Individual synoviocytes or small clusters were separated by only narrow areas of intercellular matrix. Membrane activities such as erythrophagocytosis and pinocytosis, the latter illustrated in Fig. 2, attested to the dynamic quality of the synovial lining cells as they participated in this inflammatory disease state. Frequently individual synovial lining cells were connected by slender, intercellular cytoplasmic spans. This form of cellular linkage illustrated in Fig. 2-was heretofore undiscovered by studies utilizing either light or transmission electron microscopy. Large finger-like structures depicted in Fig. 2 also jutted from some synoviocytes and either extended into the joint space or bridged gaps between adjacent synovial lining cells. In the latter situation, these filopodia perhaps served as a second type of adhesive cell contact as the layers of synoviocytes increased in depth.
Use of the Magnetostatic Analogue In Electromagnetic Lens Engineering
Authors: Coleman John W.
Published: June 2020

In the design engineering of high performance electromagnetic lenses, the direct conversion of electron optical design data into drawings for reliable hardware is oftentimes difficult, especially in terms of how to mount parts to each other, how to tolerance dimensions, and how to specify finishes. An answer to this is in the use of magnetostatic analytics, corresponding to boundary conditions for the optical design. With such models, the magnetostatic force on a test pole along the axis may be examined, and in this way one may obtain priority listings for holding dimensions, relieving stresses, etc..

The development of magnetostatic models most easily proceeds from the derivation of scalar potentials of separate geometric elements. These potentials can then be conbined at will because of the superposition characteristic of conservative force fields.
A Simple Electron Beam System for Teaching and Research
Authors: Nixon W. C.
Published: June 2020

A SIMPLE ELECTRON BEAM SYSTEM FOR TEACHING AND RESEARCH W. C. Nixon Engineering Department, Cambridge University, England The simple electron beam equipment shown in Fig. 1 has been constructed in the Engineering Dept., Cambridge University and used for several years in the Electrical Sciences Tripos course. The electron gun is at the bottom of the column below the supporting table in Fig. 1. The two micrometer screws control the specimen stage motion. The magnetic electron lenses are placed on top of each other with a spacing ring between. This ring may contain an aperture stage or specimen holder. Up to four lenses may be used at one time. The lens bores are wide enough to permit pumping through the bores so that no external vacuum manifold is needed. This means very rapid changes from one mode of experiment to another. The vacuum system is standard and manually operated. The high voltage of 25 kV and the lens current supplies are conventional and stable enough for a resolution of a few hundred Angstroms.
Thermal Recovery of Explosive-Shock Deformed Inconel 600 Alloy
Authors: Vydyanath H. R. , Murr L. E.
Published: June 2020

Inconel specimens explosively shock-loaded to pressures of 80 and 460 Kb were annealed at temperatures of 700°C and 800°C for 1 hour, and the recovery of the shocked structures was followed by hardness, and electron microscopy observations.

The initial (as-shocked) 80 Kb specimens were characterized by dense networks of dislocations with long dipoles, superjogs, etc., as shown in Fig. 1(a), whereas the as-shocked 460 Kb specimens were profusely twinned [Fig. 1(b)], the twin volume percent being 24%. The Vickers hardness numbers for the 80 and 460 Kb specimens were 265 VHN and 432 VHN respectively, an increase of 16% and 92% respectively with respect to their unshocked hardness values.
Dislocation Reactions Produced in Creep of β-NiAL
Authors: Rowe G. M. , Strutt P. R.
Published: June 2020

In previous studies, summarized by Strutt & Dodd, electron microscopy was used to identify operative glide systems in ß-NiAL single crystals deformed in high temperature creep. A summary is now given of (i) the dislocation reactions that occur, and (ii) the sub-boundaries that form as a result of the operation and interaction of these glide systems. Thin film specimens were sectioned from deformed crystals parallel to (111), and with the electron beam initially normal to this plane the specimen could be tilted in a 360° rotation and ± 45° tilt goniometer stage to obtain 12 major Bragg reflections. Two invisibilities were obtained for each dislocation segment analyzed to uniquely determine by the criterion Contrast from edge dislocations due to the displacement was considered, and in some instances image profiles were computed that took lattice elastic anistropy into account. The results are summarized briefly.
Oxidation of Single Crystal Iron Film at Very Low Pressures
Authors: Fan P. L. , Brockway L. O.
Published: June 2020

The oxidation of iron has been studied mostly with polycrystalline samples and at advanced stages of oxide formation. The formation of isolated iron oxide grains on single crystal iron films has rarely been observed. This work is to report the observation, by transmission electron microscopy, of such oxide grains formed by controlled oxidation of single crystal iron films.

Single crystal iron films were obtained by vapor deposition from an electron beam evaporator onto polished (001) faces of NaCl. The substrate, temperature was 350°C. The vacuum just before deposition was about 8 × 10−6 torr. The deposition rate was 8 - 10 A/sec and the thickness of the film was in the order of 1000 Å.
Electron-Mirror Microscopic Aspects of Ferroelectric Domains of BaTiO3 And Ca2Sr (C2H5CO2)6
Authors: Someya Teruo , Kobayashi Jinzo
Published: June 2020

Recent progress in the electron-mirror microscopy (EMM), e.g., an improvement of its resolving power together with an increase of the magnification makes it useful for investigating the ferroelectric domain physics. English has recently observed the domain texture in the surface layer of BaTiO3. The present authors ) have developed a theory by which one can evaluate small one-dimensional electric fields and/or topographic step heights in the crystal surfaces from their EMM pictures. This theory was applied to a quantitative study of the surface pattern of BaTiO3).
Variations in Surface Textures of Quartz Sand using Electron Microscopy
Authors: Amaral Eugene J.
Published: June 2020

Examination of sand grain surfaces from early Paleozoic sandstones by electron microscopy reveals a variety of secondary effects caused by rock-forming processes after final deposition of the sand. Detailed studies were conducted on both coarse (≥0.71mm) and fine (=0.25mm) fractions of St. Peter Sandstone, a widespread sand deposit underlying much of the U.S. Central Interior and used in the glass industry because of its remarkably high silica purity.

The very friable sandstone was disaggregated and sieved to obtain the two size fractions, and then cleaned by boiling in HCl to remove any iron impurities and rinsed in distilled water. The sand grains were then partially embedded by sprinkling them onto a glass slide coated with a thin tacky layer of latex. Direct platinum shadowed carbon replicas were made of the exposed sand grain surfaces, and were separated by dissolution of the silica in HF acid.
The Microstructure: of Agate and Chalcedony
Authors: Barber D. J.
Published: June 2020

Agate, a decorative natural polycrystalline form of silica, is well Known for its strength and resistance to abrasion. Moreover, agates appear to possess some of the structural characteristics now being sought in the production of ceramics and composites. Unbanded agates are dense and the grain size is small, leading to isotropy in bulk properties. This generalization breaks down in polycrystalline silica exhibiting growth bands or a marked fibrous structure. X-ray investigations apart, little attention has been given to the microstructure of these materials. It may be of value, therefore, to apply the newer techniques of scanning (s.e.m.) and transmission (t.e.m.) electron microscopy to their study. One may anticipate information on the sizes of pores in agate and chalcedony (believed to be water-filled in the latter), the nature of bands, the distribution of opal (which is deduced from X-ray data), etc. This paper reports some of the first results.
The Effect of Sulphur Impurity on the Crystallization of Calcite
Authors: Walker C. W. , Paulson G. G.
Published: June 2020

Crystal morphology may be a key to understanding the mode of formation of the mineral calcite. Morphological features include crystal shape, crystal size, macrostructure and microstructure. To define these features, a combination of optical and electron microscopes were employed. An x-ray diffractometer and a x-ray spectrometer were used as supporting equipment.

Samples were chosen on the basis of simplicity to exclude unforeseen variables such as clay or other accessory minerals which are often present in limestones. Such material was obtained from the calcite zone in the cap rock of the Minden Salt Dome, Webster Parish, Louisiana.

The calcite consists of essentially two phases as determined by x-ray diffraction; the major phase CaCO3 and the minor phase, sulphur. There is an apparent relationship between the amount of sulphur present and calcite crystal size, shape, surface microstructure and often times color.
Embedding Procedure for Water Swollen Samples
Authors: Thomas Ann M. , Shemeley Virginia
Published: June 2020

Those samples which swell rapidly when exposed to water are, at best, difficult to section for transmission electron microscopy. Some materials literally burst out of the embedding block with the first pass by the knife, and even the most rapid cutting cycle produces sections of limited value. Many ion exchange resins swell in water; some undergo irreversible structural changes when dried. We developed our embedding procedure to handle this type of sample, but it should be applicable to many materials that present similar sectioning difficulties.

The purpose of our embedding procedure is to build up a cross-linking network throughout the sample, while it is in a water swollen state. Our procedure was suggested to us by the work of Rosenberg, where he mentioned the formation of a tridimensional structure by the polymerization of the GMA biproduct, triglycol dimethacrylate.
Direct Resolution of Crystal Defects
Authors: Phillips Victor A.
Published: June 2020

The design of high resolution conventional electron microscopes has now advanced to a point where the direct resolution of crystal defects is possible in a wide range of materials. The technique involves using phase contrast instead of diffraction contrast. Information on the periodicities of the crystal planes is carried by the electron beams diffracted from these planes. By recombining one or more of these beams with the transmitted beam, fringe patterns may be obtained under appropriate conditions which represent the crystal planes and show the correct periodicities. In order to image the planes, it is necessary that the resolution of the electron microscope be not limiting. Furthermore, lens aberrations and other factors can introduce a relative phase shift between the beams used to form the image, resulting in a progressive loss of contrast and information.
Structural Imperfections in thin Oxide Films Formed on Some Fe- and Ni-Base Alloys
Authors: Lemaire L. P. , Fornwalt D. E. , Pettit F. S. , Kear B. H.
Published: June 2020

Oxidation resistant alloys depend on the formation of a continuous layer of protective oxide scale during the oxidation process. The initial stages of oxidation of multi-component alloys can be quite complex, since numerous metal oxides can be formed. For oxidation resistance, the composition is adjusted so that selective oxidation occurs of that element whose oxide affords the most protection. Ideally, the protective oxide scale should be i) structurally perfect, so as to avoid short-circuit diffusion paths, and ii) strongly adherent to the alloy substrate, which minimizes spalling in response to thermal cycling. Small concentrations (∼ 0.1%) of certain reactive elements, such as yttrium, markedly improve the adherence of oxide scales in many alloy systems.
Diffraction Contrast of Small Vacancy Clusters in Silicon
Authors: Magee T. J. , Morriss R. H.
Published: June 2020

Diffraction contrast profiles have been examined utilizing the two beam dynamical theory for a thin sample containing a spherical vacancy cluster. The differential equations describing electron diffraction amplitudes in an absorbing crystal have been given by Howie and Whelan and the strain parameter for a center of dilation in a semi-infinite solid has been derived by Mindlin and Cheng. Using a Runge-Kutta integration scheme, the contrast equations were solved numerically to yield the intensities of the transmitted and scattered beams at the exit surface of the foil. In all computations, the many beam 220 extinction distance of 723 Å was used in predicting contrast profiles.
Nucleation and Early Growth of Sputtered thin Films
Authors: Sherman Dudley M. , Hutchinson Thos. E.
Published: June 2020

The in situ electron microscope technique has been shown to be a powerful method for investigating the nucleation and growth of thin films formed by vacuum vapor deposition. The nucleation and early stages of growth of metal deposits formed by ion beam sputter-deposition are now being studied by the in situ technique.

A duoplasmatron ion source and lens assembly has been attached to one side of the universal chamber of an RCA EMU-4 microscope and a sputtering target inserted into the chamber from the opposite side. The material to be deposited, in disc form, is bonded to the end of an electrically isolated copper rod that has provisions for target water cooling. The ion beam is normal to the microscope electron beam and the target is placed adjacent to the electron beam above the specimen hot stage, as shown in Figure 1.
A Preparation of High Resolution Standards for Electron Microscopy - Part 1
Authors: Tanaka Akira
Published: June 2020

One of the means of Gemonstrating the resolving power of the electron microscope is to use the lattice image of vacuum evaporated thin single crystals. Although the technique for obtaining such single crystal films has been reported, there are many difficulties in practice, including the requirement for special vacuum evaporation equipment and highly sophisticated procedures.

This paper describes the method of obtaining single crystal films in a relatively short time. A simplified vacuum depositing unit will be described in detail as well as optimum temperatures and conditions for the substrate, annealing and controlling of the film thickness. A few examples will also be presented.
Advances of Field Ion Microscopy by the Atom-Probe Fim
Authors: Müller Erwin W.
Published: June 2020

Since its conception 15 years ago the field ion microscope has remained the only device capable of imaging a specimen in atomic detail. The unique feature of seeing point defects, dislocation cores and the atomic structure of grain boundaries and precipitates made the instrument a useful tool of physical metallurgy, particularly since various in-situ treatments and the capability of dissecting the specimen atom layer by atom layer with the help of controlled field evaporation made the bulk structure accessible. As different atoms look very much alike, a way of identifying them was needed. The most unambiguous identification, by mass spectrometry, has now been obtained with the atom-probe FIM. A single atom, as seen in the million times magnified image, can be chosen by the microscopist, picked up and sent through a mass spectrometer.
Image Intensifier with Fiber Optics Plate and Image Orthicon Tube
Authors: Mayeda M. , Yamamoto T. , Watanabe M. , Kitamura N.
Published: June 2020

When observing extremely fracturable specimens, such as organic compounds, clays and biological specimens by means of electron microscopy, it is very difficult to photograph the image of an object due to the very small current density of the irradiating electron beam. It is, therefore, desirable to use a high efficency image intensifier. The intensifiers presently used utilize Vidicon or Plumbicon camera tubes which exhibit comparatively low efficency. As a result, it is necessary to insert a photo-electron multiplier between the photo receiving surface and the surface of the camera tube. By so doing, the signal on the receiving surface is transformed into an amplified output signal, which involves considerably large shot noise arising from the collision of the photo-electron onto the electrodes or the fluorescent film in front of the second stage fiber optics plates.