bluuebunny/crossref_metadata_2025_split huggingface dataset:
Energy-Filtered, Double-Rocked Zone Axis Patterns
Authors: Higgs A. , Krivanek O. L. 
Published: June 2020

Wide angle zone axis patterns (ZAPs) have been acquired by the rock-unrock method by Eades in a Philips 400 and by Tanaka et al. in a JEM 100CX. Tanaka et al. used one set of coils before the specimen for rocking and one after the specimen for unrocking. Although this was sufficient to make the beam stationary at the detector, it did not bring it back parallel to the optic axis. Eades used two sets of coils both before and after the specimen and achieved complete de-scanning as well as complete de-rocking.When the ZAPs are to be energy filtered it is important that the beam enter the spectrometer on axis. We have therefore followed Eades' approach and used two sets of coils before the specimen (coils IA, IB) to rock the beam about a stationary point on the specimen (Fig. 1), and two sets of coils after the specimen (IIA, IIB) to de-rock the beam in a precisely reciprocal arrangement.
Crystal Structure Analysis of Cu-Zr Alloys by Convergent Beam Diffraction
Authors: Marshall A. F. , Steeds J. W. , Bouchet D. , Shinde S. L. , Walmsley R. G. 
Published: June 2020

Convergent beam electron diffraction is a powerful technique for determining the crystal structure of a material in TEM. In this paper we have applied it to the study of the intermetallic phases in the Cu-rich end of the Cu-Zr system. These phases are highly ordered. Their composition and structure has been previously studied by microprobe and x-ray diffraction with sometimes conflicting results.The crystalline phases were obtained by annealing amorphous sputter-deposited Cu-Zr. Specimens were thinned for TEM by ion milling and observed in a Philips EM 400. Due to the large unit cells involved, a small convergence angle of diffraction was used; however, the three-dimensional lattice and symmetry information of convergent beam microdiffraction patterns is still present. The results are as follows:1) 21 at% Zr in Cu: annealed at 500°C for 5 hours. An intermetallic phase, Cu3.6Zr (21.7% Zr), space group P6/m has been proposed near this composition (2). The major phase of our annealed material was hexagonal with a point group determined as 6/m.
Asbestos Microdiffraction with a High-Voltage Electron Microscope
Authors: Webber S. , Green I. S. , Ratkowski A. J. 
Published: June 2020

Conventional transmission electron microscopes (TEM) are the most commonly used analytical tools for positive identification and quantitation of asbestos in air and water samples. Selected-area electron diffraction (SAED), the accepted method of asbestos identification, often cannot yield identifiable diffraction patterns from chrysotile asbestos fibers smaller than 0.1-μm diameter. Beaman and Baker introduced microdiffraction for positive identification of 0.02-μm diameter chrysotile fibrils but this focused-beam technique is optimal only with strongly demagnifying triplecondenser TEM's.The small wavelength of the electron beam generated by high-voltage electron microscopes (HVEM) has distinct advantages for diffraction studies. The Ewald sphere at l000kV is approximately four times larger than the sphere of a l00kV beam and consequently intersects and projects more widespread points from a given plane in the reciprocal lattice. Furthermore, the beam can penetrate thicker specimens than conventional TEM's. We have assessed the capability of a double-condenser 1200kV HVEM (AEI EM7) to identify asbestos by microdiffraction.
CBED Evidence of Lattice Strain in RSR 197 Superalloy
Authors: Kersker M. , Aigeltinger E. A. , Hren J. J. 
Published: June 2020

Convergent beam diffraction is becoming more widely used as more precise crystallographic techniques become necessary. Relative lattice parameter measurements, crystallographic orientations, and crystal structure determinations are only a few applications. Carpenter [1] has used the technique to determine the Burgers vector of a dislocation in Si from one CBED pattern. Other applications to strain measurements are immediately suggested. Unfortunately, the technique is not quantitative in highly irregular strain fields unless a correlation can be made between line broadening and local strain. This paper reports the use of CBED fine structures to measure the local strain fields between γ' precipitates in a Ni-base superalloy.A Philips 400 with a FEG was used to make the strain measurements. This combination is ideal for crystallographic measurements since it has a focusable probe in the conventional TEM mode of the order of 100 Å. Using the shadow image technique, very sensitive beam placement and rapid tilting are also possible.
Nanolithography Using In-Situ Electron Beam Vaporization of Very Low Molecular Weight Resists
Authors: Isaacson M. , Muray A. 
Published: June 2020

We have begun a program of investigation of the suitability of very low molecular weiqht materials as electron beam resists for the development of structures on the nanometer scale. With the advent of reliable field emission source technology, electron sources can be produced that have brightnesses several orders of magnitude greater than existing thermionic sources. Thus, nanoamp beam currents are attainble in subnanometer diameter electron probes. This means that as little as a 10 μsec exposure is needed to deposit a dose of 1 C/cm2 in a sample. It therefore becomes reasonable to explore the ultimate limits of 1ithography, since different materials can be studied that are not necessarily as radiation sensitive as the standard high molecular weight resists (e.g., PMMA).Our explorations have centered on materials of molecular weight around 100 which could be readily vaporized under the action of the incident electron beam directly within an electron microscope ( 10-3 to 103 C/cm2). The initial pattern writing and development can then be done in one step.
Electronmicrofcopic Analysis of a Cabbage Moth Virus
Authors: Mazzone H.M. , Engler W.F. , Wray G. , Gröner A. , Zerillo R. , Bahr G.F. 
Published: June 2020

A nucleoplyhedrosis virus (NPV) has been isolated from the cabbage moth (Mamestra brassicae, Linnaeus), a serious pest insect, and bears promise of becoming an effective biological insecticide against its host. Our studies on this virus constitute part of an effort to support its approval as an insect control agent.The NPVs are characterized by the presence of polyhedral inclusion bodies, containing rod shaped virus particles. When ingested by the host insect, the inclusion bodies are broken down in the gut. The released virus particles infect and multiply in the nuclei of susceptible cells. Viruses having these properties are representatives of the Baculoviruses, subgroup A.The inclusion bodies of the cabbage moth NPV (Darmstadt strain) analyzed were approximately 1 - 2.3 um in diameter (Fig. 1). We used the HVEM to penetrate whole mount, naturally contrasted, airdried inclusion bodies to obtain their average mass value.
Use of TEM in Plant Disease Diagnosis: A Xylem-Limited Bacterium Associated with Diseased ‘Toronto’ Creeping Bentgrass
Authors: Baker Karen K. , Roberts David L. 
Published: June 2020

Plant disease diagnosis is most often accomplished by examination of symptoms and observation or isolation of causal organisms. Occasionally, diseases of unknown etiology occur and are difficult or impossible to accurately diagnose by the usual means. In 1980, such a disease was observed on Agrostis palustris Huds. c.v. Toronto (creeping bentgrass) putting greens at the Butler National Golf Course in Oak Brook, IL.The wilting symptoms of the disease and the irregular nature of its spread through affected areas suggested that an infectious agent was involved. However, normal isolation procedures did not yield any organism known to infect turf grass. TEM was employed in order to aid in the possible diagnosis of the disease.Crown, root and leaf tissue of both infected and symptomless plants were fixed in cold 5% glutaraldehyde in 0.1 M phosphate buffer, post-fixed in buffered 1% osmium tetroxide, dehydrated in ethanol and embedded in a 1:1 mixture of Spurrs and epon-araldite epoxy resins.
Structural Role of rRNAs on the Ribosomal Subunits from E. Coli by Scanning Transmission Electron Microscopy
Authors: Boublik M. , Robakis N. , Wall J.S. 
Published: June 2020

The three-dimensional structure and function of biological supramolecular complexes are, in general, determined and stabilized by conformation and interactions of their macromolecular components. In the case of ribosomes, it has been suggested that one of the functions of ribosomal RNAs is to act as a scaffold maintaining the shape of the ribosomal subunits. In order to investigate this question, we have conducted a comparative TEM and STEM study of the structure of the small 30S subunit of E. coli and its 16S RNA.The conventional electron microscopic imaging of nucleic acids is performed by spreading them in the presence of protein or detergent; the particles are contrasted by electron dense solution (uranyl acetate) or by shadowing with metal (tungsten). By using the STEM on freeze-dried specimens we have avoided the shearing forces of the spreading, and minimized both the collapse of rRNA due to air drying and the loss of resolution due to staining or shadowing. Figure 1, is a conventional (TEM) electron micrograph of 30S E. coli subunits contrasted with uranyl acetate.
An Ultrastructural Study of Particulate Matter and Ferruginous Bodies in the Sputum from Former Asbestos Workers
Authors: Dodson Ronald F. , Glenn Williams M. , McLarty Jerry W. , Hurst George A. 
Published: June 2020

Limited data exist concerning the ultrastructural assessment of the particulate content of sputum from occupationally exposed individuals. These assessments along with cytopathological screening provide valuable information about the current lung clearance patterns of these individuals.Sputum samples were collected from nine former asbestos workers who were selected because their cytopathological history included the presence of ferruginous bodies. A portion of each sample not needed for cytopathologic screening was utilized in the present study. Some of this material was fixed, embedded, and sectioned for electron microscopy, while a separate portion of the material was digested and collected on a Nuclepore filter. Energy dispersive analysis was used in assessing inorganic matter in both preparations as well as defining the core composition of the ferruginous bodies.The ultrastructural studies of the macrophage--ferruginous body interactions revealed abundant fibrillar elements (Fig. 1) in the subplasmalemmal zone of the macrophages. The extracellular boundary consisted of a halo of finegrained material separating the cell membrane from the dense ferruginous material.
Ultrasonically Induced Changes in Synapses
Authors: Borrelli M. J. 
Published: June 2020

It had previously been demonstrated that controlled ultrasonic exposures of the mammalian central nervous system (CNS) produced reversible nerve potential suppression and irreversible limb paralysis. These functional effects appeared immediately after the exposures,but no abnormal morphology was detected with the light microscope for at least 10 min, and not all exposures resulting in functional changes produced observable altered morphology. It was therefore speculated that ultrasound produced its initial effects within the tissue ultrastructure,and that some post-exposure time was required before any changes attained dimensions observable with light microscopy.Ultrasonically exposed CNS tissue has recently been examined with transmission electron microscopy and induced changes have been observed within 30 sec after the exposure. Adult female cats were anesthetized and placed in a stereotaxic unit. The animals were prepared for ultrasonic exposure of the brain as described by W. Fry and the common carotid arteries were cannulated.
Insights into the Secretory Pathway, the Mechanism of Terminal Glycosylation and Intracellular Peptide Hormone Receptors from Studies on Hepatic Golgi Fractions
Authors: Bergeron J.J.M. , Posner B.I. , Paiement Jacques , Sikstrom R. , Khan M. 
Published: June 2020

Recent studies on purified subcellular fractions of hepatic Golgi apparatus have provided insight into the functioning of the Golgi apparatusin vivo.The hepatocyte is the site of synthesis of most circulating plasma proteins. On a total protein basis, purified Golgi fractions revealed mainly secretory content (albumin, transferrin and other plasma proteins) as major constituents. After anin vivoinjection of radiolabeled leucine, newly synthesized secretory protein followed a temporal route fromcistotransregions of Golgi apparatus before appearance in the plasma. This route was revealed by studies on disrupted Golgi fractions enriched in disparate regions of the Golgi apparatus.The terminal glycosylation of secretory glcyoproteins (e.g. transferrin) can be studied by observing the transfer of UDP-(3H)-galactose to endogenous acceptors within Golgi fractions. Transfer was shown to occur to a glycolipid (dolichyl galactosyl phosphate) probably on the cytosolic aspect of the Golgi membrane. Translocation of the labeled galactose across the membrane coincided with fusion of Golgi sacculesin vitro. It is felt that during the process of Golgi membrane fusion, inverted lipid- micellar membrane structures translocate the dolichyl galactosyl phosphate from a cytosolic to a luminal orientation. Luminally oriented dolichyl galactosyl phosphate would then serve as substrate for galactose transfer to intraluminal glycopeptide acceptors via intraluminal galactosyl transferase enzyme.
Ultrastructural Observations of Ovarian Ceroid Accumulation in Mice Exposed In Vitro to Diethylstilbestrol (DES)
Authors: Wordinger R. , Miller G. 
Published: June 2020

Genetial tract abnormalities in female offspring have been reported in mice following prenatal exposure to diethylsti1bes- trol (DES). Some of these abnormalities may be ovarian-dependent since most offspring are in a persistant estrogenic state even at 12-18 months of age. Accumulation of ovarian ceroid after long-term estrogen exposure has been described by light microscopy. This study was designed to examine the ultrastructure of ceroid accumulation in ovaries of mice exposed prenatally to DES.Virgin random bred Swiss mice 6-8 weeks old, were placed with individual males and examined daily for vaginal plugs. The presence of a vaginal plug was considered Day 0 of pregnancy. Pregnant mice were given a s.c. injection of DES (10μg/kg in 0.1.cc corn oil) or corn oil on Day 15 of gestation. All animals were allowed to give birth, and offspring were weaned at 4 weeks of age. Female offspring were housed in groups of 6 until 5 months of age and then sacrificed.
Gastric Ulcers Produced by Cisplatin
Authors: Aggarwal S.K. , San Antonio J. 
Published: June 2020

Cisplatin (cis-dichlorodiammineplatinum(II)) a potent antitumor agent is now available for the treatment of testicular and ovarian cancers. It is however, not free from its serious side effects including nephrotoxicity, gastro intestinal toxicity, myelosuppression, and ototoxicity. Here we now report that the drug produces peculiar bloating of the stomach in rats and induces acute ulceration.Wistar-derived rats weighing 200-250 g were administered cisplatin(9 mg/kg) ip as a single dose in 0.15 M NaCl. After 3 days the animals were sacrificed by decapitation. The stomachs were removed, the contents analyzed for pepsin and acidity. The inner surface was examined with a dissecting microscope after a moderate stretching for ulcers. Affected areas were fixed and processed for routine electron microscopy and enzyme cytochemistry.The drug treated animals kept on food and water consistently showed bloating and lesions (Fig. 1) with a frequency of 6-70 ulcers in the rumen section of the stomachs.
Cell Fine Structure as Revealed in Dessicator-Dried Resinless Sections
Authors: Becker R. P. , Wolosewick J. J. , Ross-Stanton J. 
Published: June 2020

Methodology has been introduced recently which allows transmission and scanning electron microscopy of cell fine structure in semi-thin sections unencumbered by an embedding medium. Images obtained from these “resinless” sections show a three-dimensional lattice of microtrabeculfee contiguous with cytoskeletal structures and membrane-bounded cell organelles. Visualization of these structures, especially of the matiiDra-nous components, can be facilitated by employing tannic acid in the fixation step and dessicator drying, as reported here.Albino rats were fixed by vascular perfusion with 2% glutaraldehyde or 1.5% depolymerized paraformaldehyde plus 2.5% glutaraldehyde in 0.1M sodium cacodylate (pH 7.4). Tissues were removed and minced in the fixative and stored overnight in fixative containing 4% tannic acid. The tissues were rinsed in buffer (0.2M cacodylate), exposed to 1% buffered osmium tetroxide, dehydrated in ethyl alcohol, and embedded in pure polyethylene glycol-6000 (PEG). Sections were cut on glass knives with a Sorvall MT-1 microtome and mounted onto poly-L-lysine, formvar-carbon coated grids while submerged in a solution of 95% ethanol containing 5% PEG.
Localization of Calcific Deposits in Aortic Valve Leaflets by Radiography, X-Ray Analysis, and Transmission Electron Microscopy
Authors: Colonna Kathryn N. , Breese Sydney S. , David Deck J. 
Published: June 2020

Bioprosthetic heart valves composed of preserved tissue frequently calcify over a period of years after implantation in place of diseased natural valves. Recent experiments which implanted porcine aortic valves in young calves were followed less than four weeks later by beginning calcification of valve leaflets. To confirm, localize and measure the varying densities of calcific deposits, leaflet tissues were systematically examined by radiography, energy dispersive x-ray analysis and transmission electron microscopy.Soft x-ray photography of recovered valves demonstrated tissue densities, presumably calcified sites, fanning into the leaflets from similarly dense areas of leaflet attachment to the aortic wall (Fig. 1). Regions of leaflets showing a range of densities were excised and critical-point dried for scanning electron microscopy and x-ray microanalysis. Samples from areas of unimplanted valves radiographically free of dense aggregations were excised and prepared similarly for controls. These specimens were examined by means of the scanning and x-ray modes of a JEOL-100 CX electron microscope with an attached KEVEX-7000 micrg-x-ray analyzer at 60 KEV and 300x magnification.
Ions and Water in Cells and Tissues Studied by Microprobe Analysis of Frozen-Hydrated Sections in the SEM
Authors: Gupta Brij L. , Hall T. A. 
Published: June 2020

Electrolyte elements including Na, K, Cl, Ca and Mg are increasingly implicated in a variety of cell and tissue functions. A proper understanding of their role requires knowledge of the distribution of these elements in and around cells at microscopic levels. There has been a lack of suitable methods to measure elemental concentrations in microvolumes in situ. The electron probe x-ray microanalysis (microprobe analysis) of frozen sections is proving effective in providing such data.The total concentrations in subcompartments measured by microprobe analysis can be compared with the free concentrations and the activities measured by other methods such as microelectrodes to yield information on the possible binding or sequestration sites for the elements concerned.Method. The technique of microprobe analysis of thick(>0.5 μm) frozen-hydrated sections in a scanning electron microscope column (SEM) was initiated and developed and has been applied in our laboratory to investigate a range of cellular transport processes.
Entry of Membrane Viruses into Animal Cells
Authors: Simons K. , Matlin K. , Reggio H. , Helenius A. 
Published: June 2020

Recent work in this laboratory has shewn that Semliki Forest virus, an enveloped alphavirus, enters BHK-21 cells by adsorptive endocytosis in coated vesicles, and is routed via endosemes (prelysosomal vacuoles) into the lysoscmal compartment where the low pH induces a fusion reaction between the virus membrane and the lysoscmal mentorane.This fusion event introduces the virus nucleocapsid into the cytoplasm where virus replication commences.We have now studied hew two other enveloped viruses, fowl plague virus (FPV), an influenza virus and vesicular stomatitis virus (VSV), a rhabdovirus, enter into MDCK-cells. FPV binds to sialic acid- containing receptors, mainly located on microvilli of the cell surface. The surface-bound virus is rapidly internalized through coated pits into coated vesicles which prcbably fuse with endosemes. From here the virus is routed into lysosomes. Biochemical assays shewed that surface-bound viruses are internalized with a half-life of 10-15 minutes. This is in the same range as previously described for Semliki Forest virus and physiological ligands internalized into the cell by receptor-mediated endocytosis.
The Ultrastructure of the Human Bronchial Submucosa
Authors: Brinkman G. L. , Brooks N. , Bryant V. 
Published: June 2020

Up until now the only clinical interest in the human submucosa has centered around the hypertrophy of the mucous secreting glands in patients with chronic cough and sputum. Besides this function, the submucosa, which is a loose connective tissue, provides mechanical and functional support for the mucosa and also contains numerous cells whose contribution to bronchial physiology is not yet fully understood.The mucosa is separated from the submucosa by the basement membrane, which is a thin, amorphous sheet between these two tissues. Auerbach has reported budding of the mucosal cells into the basement membrane in cigarette smoking dogs; a similar finding is shown in Figure 1 in a human cigarette smoker. Immediately beneath the basement membrane is a collection of reticular fibers which vary from being a thin layer of light density to a dense, thick layer of fibers. The reticular fibers are smaller, shorter and thinner than collagen fibers, and always single.
Myocardial Alterations in Animals Following High Altitude Exposure
Authors: Bischoff M. B. , Dean W. D. , Bucci T. J. , Frics L . A. 
Published: June 2020

There is a paucity of morphological evidence, particularly at the ultrastructural level, to correlate with tile physiological effects of chronic exposure to high altitude. In this study the myocardium of dogs and rabbits subjected to five months exposure at an altitude of 14,110 feet was compared to that of animals residing at sea level. The animals kept at 14,110 feet were shipped from sea level (160 feet) witnout acclimatization at intermediate altitudes.The physiological parameters including the hematologic changes, pulmonary artery pressures, pulmonary artery oxygen saturations, electrocardiograph changes, right ventricular weight to body weight and right ventricular weight to total heart weight ratios observed in these animals have been reported previously.The animals were necropsied at the end of the five months. The myocardium was quickly removed, cut into small pieces and immersed in 1% osmium tetroxide buffered with veronal acetate. Following fixation the tissues were dehydrated in ascending ethanol concentrations followed by propylene oxide and embedded in Epon 812. Ultrathin sections were doubly stained in uranyl acetate and lead citrate.