bluuebunny/crossref_metadata_2025 huggingface dataset:
Type IV glyogenosis: Electron microscopic characterization of cytoplasmic accumulations
Authors: Simons P.K.
Published: June 2020

Type IV glycogenosis (amylopectinosis) is a heritable disease resulting from the deficient activity of the enzyme amylo-l,4--l ,6-transglucosidase. The clinical manifestations include hepatomegaly, portal fibrosis, and cirrhosis. In the strict sense of the term, this is not a true glycogenosis since the tissue concentration of glycogen has been reported as normal or even decreased, although the few light microscopic studies available have shown a definitive deposition of an abnormal storage material in a number of tissues but especially in the liver. While the histologic picture is inconclusive and may mimic other conditions, particularly alpha-l-antitrypsin deficiency, the electron microscopic pattern is quite unique and has been described elsewhere. The purpose of this study was to closely examine and characterize the storage material found in liver cells of a case of Type IV glycogenosis.
T.E.M. analysis of fine needle aspirate glomeruli
Authors: Rowden G. , Dean S. , Campbell J. , Belitsky P.
Published: June 2020

Fine needle aspiration cytology is currently of great interest in the diagnosis of tumors and also in monitoring the course of organ transplants (1-4). Specimens may be procured with little associated trauma to the tissue or discomfort to the patient (5,6). In the case of kidney transplantation, daily biopsies may be carried out to determine the possible onset of rejection episodes (4). Cytological assessment of the types and extent of any mononuclear cell infiltrate are critical in determining the possible immunosuppressive protocols that are used in kidney grafting (6). T.E.M. studies of fine needle aspirates from kidney specimens are very limited and little attention has been paid in such cases to glomeruli present in the samples. Glomerular changes although not critical in renal transplant rejection are of great interest in diagnosis of many renal diseases.
Electron microscopy in diagnostic virology
Authors: Miller S. E.
Published: June 2020

The techniques for detecting viruses are many and varied including FAT, ELISA, SPIRA, RPHA, SRH, TIA, ID, IEOP, GC (1); CF, CIE (2); Tzanck (3); EM, IEM (4); and molecular identification (5). This paper will deal with viral diagnosis by electron microscopy and will be organized from the point of view of the electron microscopist who is asked to look for an unknown agent--a consideration of the specimen and possible agents rather than from a virologist's view of comparing all the different viruses. The first step is to ascertain the specimen source and select the method of preparation, e. g. negative stain or embedment, and whether the sample should be precleared by centrifugation, concentrated, or inoculated into tissue culture. Also, knowing the type of specimen and patient symptoms will lend suggestions of possible agents and eliminate some viruses, e. g. Rotavirus will not be seen in brain, nor Rabies in stool, but preconceived notions should not prejudice the observer into missing an unlikely pathogen.
Ultrastructural immunocytochemistry in diagnostic pathology
Authors: Huang Shao-nan
Published: June 2020

The objectives of this communication include the following: (1) to illustrate some aspects of practical ultrastructural immunocytochemistry, thus examplifying its value in diagnostic pathology, and (2) to compare the sensitivity, specificity and technical complexity of the three methods, i.e., protein Agold (PAG), immunoferritin (IFe) and peroxidase-antiperoxidase (PAP).

For the immunogold method, monodispersed gold particles were obtained with the use of sodium citrate as the reducing agent on chloroauric acid solution. The PAG complex was then prepared according to the method described by Horisberger. The efficacy of PAG is assessed by its ability to bind the preformed immune complexes, such as shown in FIG.1, a smear preparation of hepatitis B core antigen (HBcAg) immune complex. A high degree of specific labelling with PAG would ascertain its high efficacy in immunocytochemical staining. Prior treatment of the immune complexes with protein A blocks the subsequent labelling with PAG, thus indicating specificity.
Imaging of platinum-shadowed macromolecular complexes in dark field
Authors: Andrews D.W. , Ottensmeyer F.P.
Published: June 2020

Shadowing with heavy metals has been used for many years to enhance the topological features of biological macromolecular complexes. The three dimensional features present in directionaly shadowed specimens often simplifies interpretation of projection images provided by other techniques. One difficulty with the method is the relatively large amount of metal used to achieve sufficient contrast in bright field images. Thick shadow films are undesirable because they decrease resolution due to an increased tendency for microcrystalline aggregates to form, because decoration artefacts become more severe and increased cap thickness makes estimation of dimensions more uncertain.

The large increase in contrast provided by the dark field mode of imaging allows the use of shadow replicas with a much lower average mass thickness. To form the images in Fig. 1, latex spheres of 0.087 μ average diameter were unidirectionally shadowed with platinum carbon (Pt-C) and a thin film of carbon was indirectly evaporated on the specimen as a support.
Toward ordered arrays of the proton transport F1F0-ATPase
Authors: Loren Buhle E. , McEnery Maureen W. , Petersen Peter L. , Aebi Ueli
Published: June 2020

Proton transporting ATPases are large multisubunit enzymes that can be isolated from membrane systems and catalyze the phosphorylation of adenosine diphosphate (ADP) by inorganic phosphate (Pi) to form adenosine triphosphate (ATP). The rat liver F1F0-ATPase complex can be biochemically separated into an F1 portion containing the catalytic activity and weighing approximately 384,000 daltons [1] and an F0 portion, estimated to weigh 100,000 daltons [2] and believed to span the inner mitochondrial membrane [1]. The structure of the F1 portion of the rat liver proton ATPase has recently been determined by X-ray diffraction analysis to 9.0Å [3]. No ordered forms suitable for structural studies by X-ray crystallography or high resolution electron microscopy of the F1F0-ATPase complex from any species have been reported to date.
Localization of bombesin at the electron microscope level employing the modified ABC method in the rat neostriatum
Authors: Bradley Ronald H.
Published: June 2020

Bombesin was originally isolated from frog skin (1) and it has been recently localized with the CNS (2). Bombesin has been shown to bind certain pharmacological drugs such as diazepams within the CNS (3). Recent investigations by our lab have been successful in localizing other putative neurotransmitter candidates such as methionine enkephalin, leucine enkephalin, substance P and GAD with the modified avidin-biotin complex technique within rat neostriatum (4). The present study was designed to localize bombesin in somata of neostriatal neurons in rats that were treated with colchicine to increase somatal neurotransmitter concentrations.

The increase of somatal bombesin, a putative neurotransmitter, was accomplished by bilateral stereotaxic intraventricular injections of 15 µ1 (10 µ1/µg) colchicine per ventricle. Following a 48 hr survival time, the rats were intracardially perfused with our modified immunocytochemical buffer (3) which contains 1% glutaraldehyde, 1% paraformaldehyde in a microtubule stabilizing buffer (MSB) at pH 7.1 (37°C).
SEM evaluation of the TEM cold-stage double-film specimen
Authors: Bellare Jayesh
Published: June 2020

Seeing is believing, but only after the sample preparation technique has received a systematic study and a full record is made of the treatment the sample gets.

For microstructured liquids and suspensions, fast-freeze thermal fixation and cold-stage microscopy is perhaps the least artifact-laden technique. In the double-film specimen preparation technique, a layer of liquid sample is trapped between 100- and 400-mesh polymer (polyimide, PI) coated grids. Blotting against filter paper drains excess liquid and provides a thin specimen, which is fast-frozen by plunging into liquid nitrogen. This frozen sandwich (Fig. 1) is mounted in a cooling holder and viewed in TEM.

Though extremely promising for visualization of liquid microstructures, this double-film technique suffers from a) ireproducibility and nonuniformity of sample thickness, b) low yield of imageable grid squares and c) nonuniform spatial distribution of particulates, which results in fewer being imaged.
Radiation effects in Langmuir-Blodgett films
Authors: Joy D. C. , Ellington M. , Rozenshtein L.
Published: June 2020

The process of making multi-layer films of fatty acids by repeated deposition of monolayers from the surface of a liquid to the surface of a solid was first described nearly fifty years ago. Although for most of the intervening years these “Langmuir - Blodgett” films have remained laboratory curiosities they are now the subject of considerable attention because of their many special properties. One area of such interest is that of high resolution electron beam lithography. The minimum line width that can be fabricated in a resist is governed by the amount of energy needed to initiate the lithographic action. In conventional polymer resists such as PMMA, where cross-linking is the mechanism, electrons of only a few eV energy can cause exposure. Consequently secondary electrons participate in the exposure process and limit the minimum line width attainable.
Ultrastructural study of tobacco mosaic virus-infected chloroplasts
Authors: Henry Egbert W.
Published: June 2020

There have been several reports on the effects of tobacco mosaic virus (TMV) infection in Nicotiana tabacum leaf tissue. TMV infection does not appear to have an exact or precise infective selectivity, with respect to particular tissues. The tissue abnormalities such as lignification, suberization, vein banding, and vein clearing, may not be direct tissue responses to TMV infection. However, it has been suggested that plasmodesmata and possibly ectodesmata, may represent the actual sites of TMV infection, especially the plasmodesmata of the basal septum.

TMV infection has also been implicated in host resistance vs. the levels of phenolic-type enzymes. A rise in oxidative metabolism has been associated with TMV infection, thus causing an increase in the, activity of peroxidase, polyphenol oxidase and phenylalanine ammonia-lyase. In addition, TMV infection may cause a lowering of o-dihydric phenols such as chlorogenic acid in some tissues.
Resolution at its Current Limit: Applications of the Berkeley ARM
Authors: Gronsky R.
Published: June 2020

The Atomic Resolution Microscope (ARM) is a high voltage electron microscope manufactured by JEOL, Ltd. to achieve a point-to-point resolution consistently at or better than 0.18 nm over its entire 400 kV to 1000 kV accelerating potential range. Both the history of the project and details of the instrument have been previously reviewed. Now located within the National Center for Electron Microscopy, the ARM is made available by the Department of Energy for use by all microscopists submitting an approved proposal. The purpose of this paper is to highlight some of its recent and planned applications which exploit its superior resolution.
Electron microscopy of high performance PBO and ABPBO polymers
Authors: Krause S. J. , Haddock T. , Adams W. W.
Published: June 2020

Recent developments in the synthesis and preparation of high molecular weight polymers have resulted in the generation of two new aromatic heterocyclic polymers with excellent mechanical properties. The polymers are the rigid rod poly-p-phenylene benzobisoxazole (PBO) and the flexible coil poly 2,5(6) benzoxazole (ABPBO). The purpose of this study was to characterize the morphology of PBO and ABPBO in as-spun (AS) and annealed (AN) conditions by the use of transmission electron microscopy (TEM) imaging and diffraction techniques, and to compare the results with other high performance polymers.

Samples were prepared for TEM by detachment replication. A JEOL 100CX was operated at 120 kV. Dark field images were formed from the first, second, and third equatorial reflections in the case of PBO, and from the first and second equatorial reflections for ABPBO. In order to minimize beam damage artifacts, the areas of the sample used for dark field imaging were adjacent to those used for locating and focusing.
Combined TEM/SEI of polymer membranes
Authors: Sawyer L. C.
Published: June 2020

Structure-property relationships are important in the process optimization and fundamental understanding of many polymeric materials, including membranes. Polymer membranes are currently being used for separation, concentration or purification in a wide range of industrial process applications. The process used to manufacture the membrane, and the polymer type, determines the morphology, which influences the membrane transport properties and potential applications. The morphology includes: pore size, shape, distribution and their overall three dimensional arrangement. Microscopical methods are needed to image the structures formed by the various processes, in order to systematically study changes in variables for specific applications.
The void lattice in α-Al2O3
Authors: Lee W.E. , Jenkins M.L. , Pells G.P.
Published: June 2020

Alignment of irradiation-induced voids along specific crystallographic directions has been observed in many monatomic bcc, fee and cph metals. Observations of void alignment in diatomic materials, however, have been limited to just three cases: electron-irradiated CaF2 and SrF2 and neutron or heavy-ion irradiated α-Al2O3. We describe here a study of the evolution of the void lattice with increasing dose in heavy-ion irradiated α-Al2O3.

Thin (∽50μm) polished, single crystals of α-Al2O3 were irradiated with 4MeV Ne+ and Ar+ ions to doses up to 30dpa over a range of temperatures from 500-900°C. Specimens were progressively backthinned through the damage profile by ion-beam milling and were examined at various stages in a Philips EM400 STEM. Voids were imaged using phase (defocused) contrast techniques.
Inhomogeneities in hot-pressed silicon nitride
Authors: Donlon W.T. , Shinozaki S. , Mindroiu V. , Beckwith E.C. , Ezis A.
Published: June 2020

Silicon nitride is currently being applied in wear applications such as cutting tools (1-2) and is being actively investigated for use as structural components in ceramic heat engines (3). Processing flaws and metallic inclusions such as Fe,Al, and free silicon are known to influence the physical and mechanical properties of the final product.

In this investigation, flaws in a hot-pressed silicon nitride containing Y2O3 were identified using optical, scanning electron, (SEM) and transmission electron microscopy (TEM).

A representative microstructure of the silicon nitride which was investigated is shown in Fig. 1. The size of typical β-Si3N4 grains is less than one micron, and the intergranular phase (which is rich in yttrium) is completely crystalline and appears dark in this bright-field micrograph.
Analytical electron microscopy of SiC implanted with Cr ions
Authors: Sklad P. S. , Angelini P. , McHargue C. J. , Williams J. M.
Published: June 2020

Silicon carbide is an attractive structural material for high temperature applications that require chemical stability in aggressive environments and wear resistance. In order to investigate ion implantation as a means of improving surface properties, specimens of SiC were implanted with chromium ions. The present work is concerned with characterizing the near-surface microstructure produced by implantation and monitoring changes which occur during post-implantation annealing.

A polycrystalline specimen of α SiC, pressureless sintered with boron additions by the Carburundum Co., was implanted with chromium ions at ambient temperatures. In order to obtain a broad fairly uniform depth distribution a multiple-energy implant schedule was employed: 4.03 x 1015 Cr ions/cm2 were implanted at 95 keV, 7.26 x 1015 Cr ions/cm2 were implanted at 190 kev, and 10 x 1015 Cr ions/cm2 were implanted at 280 keV.
In-situ reduction of ferrites
Authors: Tucker D.S. , Porter J.R.
Published: June 2020

An environmental cell equipped TEM can be used to observe gassolid reactions directly. In previous work, the hematite-magnetic reaction was studied by ‘in-situ’ HVEM. The direct observation of the nucleation of reduced phases and the development of porosity provided information to complement kinetic experiments. When mixed oxides, such as zinc ferrite and nickel ferrite, are reduced, cation segregation across the reduction interface can occur, with the possibility of rate control by the back segregation of one cation ahead of the reduction interface. An EDS capability allows changes in the cation ratio ahead of the reduction interface to be monitored after reduction.
Intergrowths and aggregates of natural kaolinite
Authors: Hurst V. J. , Rigsby W. E.
Published: June 2020

Kaolinite crystallites, which are pseudohexagonal platelets, generally are found not singly but as intergrowths or aggregates of several platelets.

Until recently only coarser intergrowths (Figs. 1-2) could be imaged with SEM in sufficient detail for intersectional relationships to be unambiguously interpreted. With newer SEMs, the smallest intercrystal relations can be resolved. Floccules can be distinguished from intergrowths. In-situ crystallization texture (Fig. 3) can be distinguished from sedimentational fabric (Fig. 4).
High-resolution image processing of bright-field electron micrographs
Authors: Kirkland E.J. , Siegel B.M. , Uyeda N. , Fujiyoshi Y.
Published: June 2020

A general form of the analytical model of a CTEM bright field image is:

(1)

where G is the Fourier Transform (F.T.) of the recorded image intensity, F is the F.T. of the complex specimen transmission function, CO is a background constant, δ is the Dirac delta function, N is a random noise component, is a spatial frequency vector in the image plane, and Tμ is the transmission cross coefficient. In the special case of coherent imaging:

(2)

(3)
Study of precipitation in 90W-5Ni-5Fe using stereo TEM
Authors: Posthill J.B.
Published: June 2020

Tungsten-based heavy alloys have received considerable attention since 1935 when McLennan and Smithells reported the development of a 90wt%W-balance Ni,Cu alloy that was produced by liquid-phase sintering. In the past fifteen years the majority of heavy alloy research has concentrated on the W-Ni-Fe system because of its superior mechanical properties. The commercially-produced 90W-5Ni-5Fe alloy basically consists of two phases; a network of contiguous bcc W-phase spheroids (98.8at%W-0.1at%Ni-1.1at%Fe) that are 20-30 μm in diameter embedded in a fcc matrix γ-phase (19.2wt%W-41.4wt%Ni-39.4wt%Fe). The mechanical properties of the alloy are governed by the properties and microstructure of the respective phases and the W-γ and W-W boundaries. This contribution is concerned with a precipitation reaction that occurs within the W-phase.
Microstructural evaluation of a rapidly solidified Ti alloy containing Er and B
Authors: Koch E. F. , Rowe R. G.
Published: June 2020

The high strength to density ratio of titanium alloys make them ideal for applications where weight and moderate temperature resistance are critical. The maximum temperature for use of state of the art titanium alloys which are solid solution strengthened is on the order of 1000-1100°F. The chemical stability of most precipitate phases has been shown to be inadequate for the precipitaion strengthening of titanium alloys in this temperature range. Recently, it has been shown that alloying with rare earth elements combined with rapid solidification from the melt can produce stable rare earth oxide dis-persoids which have the potential for dispersion strengthening, and thus increase the high temperature capabilities of titanium alloys. In this paper, we describe the microstructural evaluation using analytical electron microscopy of rapidly-solidified filaments of titanium alloys containing rare earth and boron additions.
Image compression: Rate versus distortion assessment
Authors: Pennebaker William B. , Gonzales Cesar A. , Mitchell Joan L.
Published: June 2020

The aim of digital image coding for compression is to minimize memory for storage and/or bandwidth for transmission. In the case of grayscale images, compression is typically accompanied by some distortion or loss of information in the reconstructed image. Generally, the larger the distortion, the better the compression; a balance between these competing trends has to be achieved in any practical coding design. Different coding schemes can result in distortions which are perceived differently by viewers. These various schemes can also give different compression rates, but rate comparisons among them are hampered by the lack of a good measure of image fidelity consistent with subjective appreciation of image quality by the human viewer. A problem that is simpler, but still useful, is the study of the rate-distortion tradeoff for a particular type of distortion such as that produced by a particular class of coders.
Three-dimensional displays of computer-generated and real images
Authors: Sher Lawrence D.
Published: June 2020

This paper discusses a new generic kind of computer-generated display, one which can realistically be described as having depth rather than depth cues. It was developed to its present state by this author and has been called SpaceGraph, a name which will be used here.

Computer output is normally on paper or on a CRT, both of which are nominally flat. The SpaceGraph display provides computer output which is not flat. Its output is displayed in a volume. The output can take two basic forms: a computer-generated figure, like a stick figure of a molecule, or image data acquired from a volume sensing system, e.g., as encountered in reconstruction from projections or from serial sections. Since the display volume's spatial z-axis is just as real and as versatile as its x- or y-axes, the user has a wholly new display resource.
The on-line use of histogram data for high-speed correction and alignment of electron microscope images
Authors: Krakow William
Published: June 2020

In the past few years on-line digital television frame store devices coupled to computers have been employed to attempt to measure the microscope parameters of defocus and astigmatism. The ultimate goal of such tasks is to fully adjust the operating parameters of the microscope and obtain an optimum image for viewing in terms of its information content. The initial approach to this problem, for high resolution TEM imaging, was to obtain the power spectrum from the Fourier transform of an image, find the contrast transfer function oscillation maxima, and subsequently correct the image. This technique requires a fast computer, a direct memory access device and even an array processor to accomplish these tasks on limited size arrays in a few seconds per image. It is not clear that the power spectrum could be used for more than defocus correction since the correction of astigmatism is a formidable problem of pattern recognition.
High energy resolution spectrometer for the dedicated STEM
Authors: Batson P.E.
Published: June 2020

Use of the STEM to obtain precise electronic information has been hampered by the lack of energy loss analysis capable of a resolution and accuracy comparable to the 0.3eV energy width of the Field Emission Source. Recent work by Park, et. al. and earlier by Crewe, et. al. have promised magnetic sector devices that are capable of about 0.75eV resolution at collection angles (about 15mR) which are great enough to allow efficient use of the STEM probe current. These devices are also capable of 0.3eV resolution at smaller collection angles (4-5mR). The problem that arises, however, lies in the fact that, even with the collection efficiency approaching 1.0, several minutes of collection time are necessary for a good definition of a typical core loss or electronic transition. This is a result of the relatively small total beam current (1-10nA) that is available in the dedicated STEM. During this acquisition time, the STEM acceleration voltage may fluctuate by as much as 0.5-1.0V.
Site symmetry effects in the EELS fine structure of Be2C
Authors: Disko M.M. , Spence J.C.H. , Sankey O.F.
Published: June 2020

A relationship between observed electron energy loss near edge fine structure (ELNES) and the local site symmetry of the excited atomic species has recently been demonstrated by Taftϕ and Zhu. These workers have shown that the K edge ELNES (0 to 20 eV above threshold) of Mg and Al octahedrally coordinated by oxygen is dominated by a single peak approximately 10eV wide, while the K edge ELNES of Mg, Al, and Si at tetrahedral sites exhibit one or two narrow (width 5eV) features. We present here an initial study of similar behavior in the antifluorite structure crystal Be2C. This system was selected because C is at an octahedral site and Be is at a tetrahedral site (see Fig.1) Furthermore, the light elements involved make acquisition of the ELNES signal less difficult than for heavier elements.
X-ray microanalysis of ion-implantation profiles in backthinned specimens
Authors: Bentley J. , Angelini P.
Published: June 2020

As an alternative to the use of cross-sectioned specimens, a method which uses backthinned specimens has been developed for the measurement of concentration profiles in ion-implanted materials. The technique is less direct but avoids the sometimes insurmountable problems associated with the preparation of suitable cross-sectioned specimens and is more applicable to low-energy implants where the penetration depth is small. A series of x-ray spectra is measured in a wedge-shaped, backthinned foil.
The simulation of tilt boundary images viewed edge-on at moderate and very high resolutions
Authors: Krakow William , Wetzel Jeffrey T.
Published: June 2020

Several high resolution electron microscope studies of grain boundary structure have concentrated on semiconducting materials or Si/metal silicide interfaces because of the somewhat larger atomic spacings than metals and alloys. Some success in the study of metallic interfaces has been achieved with 200kV and 1meV microscopes, at least from the point of view of obtaining experimental images, for a ∑=41 boundary in molybdenum and [110] tilt boundaries in Au. In these papers exacting analysis of atomic positions and subtle contrast features at the interfaces were not pursued because image computations were not available. The questions which have not yet been addressed must therefore include not only good structural models for image computations but, more immediately, the question of a microscopes performance at the 2Å resolution level. Further impetus to evaluating boundary structures in metals has also been enhanced by the soon to become commercially available 300 and 400kV short focal length microscopes which will have performance characteristics well below the resolution required for most metallic interfaces.
Calculated images of dolomite - calcite interfaces: Feature identification in saddle dolomite
Authors: King A.H. , Chen Fu-Rong , Reeder R.J. , Barber D.J.
Published: June 2020

Images of saddle dolomite show defects which appear as fringe contrast effects as seen in Fig.1. These defects appear to branch or terminate, frequently without any sign of a dislocation, indicating that the nature of the defects is not that of a stacking fault, at least in the usual sense of that term. The possibility that the faults are merely thin layers of compositional variants of the parent phase has accordingly been investigated.

The mineral phases dolomite, CaMg(CO3)2 and calcite, CaCO3, have very similar structure, both having rhombohedral unit cells with very similar lattice parameters: calcite may be obtained from dolomite by substituting calcium on the sites normally occupied by the magnesium ions. The problem of computing the bright field and dark field intensities for a fault arranged as in Fig.2 is particularly amenable to a scattering matrix approach, and we have carried out two-beam calculations to compare the main features of the images with those of the calculated intensity profiles.
The edge-on electron microscopy of multilayered Au/Ag films
Authors: Baxter C.S. , Somekh R.E. , Stobbs W.M.
Published: June 2020

Multilayered metallic films exhibit property anomalies at layer spacings ≲2nm but it is not known if these are generally associated with structural changes. We are therefore investigating the application of “edge-on” transmission electron microscopical techniques to the examination of films of this type. The observations reported here are of Au/Ag films with modulation wavelengths 19nm and 5nm grown epitaxially on a silver substrate on (001) NaCl using a dual source D.C. magnetron sputter deposition system with a base pressure of 0.06μPa. The longer wavelength (19nm) film was grown at an argon sputtering pressure of 5Pa on a substrate at 250°C, while the shorter wavelength film was grown at 7Pa on a substrate at 160°C. The deposition rates were about 0.5nm sec-1 at a target/substrate separation of 50mm. It can be seen from figures 1 and 2 that in both cases the films have even layer spacings and flat interfaces, except where a few layers of about lnm were introduced into the 5nm wavelength film. The edge-on TEM foils were produced by ion beam thinning at liquid N2, temperatures.
HVEM irradiation and oxidation of zirconium
Authors: Herring R.A.
Published: June 2020

The oxidation of electropolished zirconium has been studied using an AEI EM7 HVEM. Two types of experiments have been performed. In the first experiment a specimen was examined at 1 MeV and 400 KeV while it was heated to 675 K at 20 torr oxygen pressure in an environmental cell. It was questioned whether HVEM irradiation could produce cubic zirconia, as has been produced during ion and neutron irradiationd. In the second experiment, thin layers of oxide formed during examination at 675 K in the HVEM operating at a vacuum level of ∼10-6 torr were removed from the underlying metal by electropolishing and subsequently examined in the HVEM.
1250-kilovolt scanning transmission electron microscope
Authors: Imura T. , Maruse S. , Mihama K. , Iseki M. , Hibino M. , Saka H. , Kubozoe M. , Matsui I. , Satoh H. , Katagiri S.
Published: June 2020

Ultra high voltage STEM has many inherent technical advantages over CTEM. These advantages include better signal detectability and signal processing capability. It is hoped that it will explore some new applications which were previously not possible. Conventional STEM (including CTEM with STEM attachment), however, has been unable to provide these inherent advantages due to insufficient performance and engineering problems. Recently we have developed a new 1250 kV STEM and completed installation at Nagoya University in Japan. It has been designed to break through conventional engineering limitations and bring about theoretical advantage in practical applications.

In the design of this instrument, we exercised maximum care in providing a stable electron probe. A high voltage generator and an accelerator are housed in two separate pressure vessels and they are connected with a high voltage resistor cable.(Fig. 1) This design minimized induction generated from the high voltage generator, which is a high frequency Cockcroft-Walton type, being transmitted to the electron probe.
Some data of a superconducting lens with iron circuit
Authors: Lefranc G. , Anzinger H. , Knapek E. , Dietrich I.
Published: June 2020

In our laboratory the electron optical data of several iron free lens types were calculated from their axial field distribution /1/. One of these lens types, the shielding lens, which was especially suitable for our purposes has been constructed for practical application and it is now in operation in several electron microscopes. A point to point resolution of 0.15 nm could be established and the specimen drift could be reduced in comparison with conventional microscopes to 0.03 nm/min. The shielding lens is particularly of advantage for high voltage microscopes. But the performance is also satisfactory in the 100 kV range.

The shielding material, however, we use for our shielding lens is not commercially available and the machining of this material is difficult. For this reason we wanted to find out if in principle a superconducting iron circuit lens could replace the shielding lens in our system (Fig. 1) at lower beam voltages, i.e. if an iron circuit lens with the same dimensions and the same electron optical data could be constructed.
On-line computer archival storage of thin specimen images by means of STEM
Authors: Okagaki T. , Jones M. , Clark B.A. , Pan T. , Hsing R. , Tzou H.H.
Published: June 2020

The computer archiving of diagnostic electron photomicrographs of thin sections has inherent merits: (1) a large amount of dark room processes can be eliminated, (2) an image file in the archive can be easily accessed and displayed, (3) the archive can be incorporated into a hospital or laboratory based computer information data bank, (4) an image can be easily enhanced and its contrast and grey level can be adjusted to the optimum for interpretation, (5) grey scale linearity can be preserved for future densitometry, (6) morphometry and pattern recognition can be applied, and (7) a distribution map of data from analytical electron microscopy can also be incorporated.

Although a photographic film can store an extremely large amount of information, recent development of large storage devices, notably optical (laser) disks, make archiving of a high resolution digitized image physically and economically feasible.
Stability of osmium carbonyl cluster catalysts in different reaction environments
Authors: Datye A. K. , Allard L. F. , Schwank J. , Gates B. C.
Published: June 2020

There is considerable interest in the nse of organometallic clnster compounds bound to oxide supports as heterogeneous catalysts. In particular, clusters derived from Os3(CO)12 are known to react with terminal OH groups on metal oxides to yield HOs3(CO)10-O-M where M can be Si or Al. In a previous study we have reported high-resolution electron micrographs of such Os3(CO)12 derived catalysts supported on A12O3. We found ca. 0.5 nm scattering centers to be clearly visible in samples that had undergone a 2 hr treatment in flowing Argon at 473 K. The catalysts were characterized by IR spectroscopy and other techniques to establish that the 3 osmium atom triangular framework was intact even on the supported samples. The samples treated in Argon were remarkably stable even under prolonged examination with 100 keV electrons. However, when the catalysts were treated in flowing H2 also at 473 K for 2 hr the resulting particles were unstable and disappeared in the course of extended observation in the microscope.
Real fibre diameters from freeze-etched Pt-C replicated fibre images: A DNA study
Authors: Ruben George C. , Marx Kenneth A.
Published: June 2020

Not only is recognition of characteristic filament surface structure important in identifying filaments of cellular origin but so is a reliable method for accurately measuring real filament width. Although a number of methods have been reported for estimating filament diameters these replication techniques are inappropriate for resolving filament surface detail to 12Å. To investigate how Pt-C metal replication changes the thickness of single or paired tightly wrapped hydrated DNA double helices, we have measured fibres with their long axis oriented (±5°) in the direction of metal replication in freeze-etched preparations. These fibres are coated with metal on both sides of their upper surface and are suspended horizontally above the ice surface over unshadowed regions so that both fibre edges are clearly delineated. The materials and methods have been described previously.
High-resolution structural analysis of eukaryotic ribosomal RNAs by scanning transmission electron microscopy
Authors: Oostergetel G.T. , Hainfeld J.F. , Wall J.S. , Boublik M.
Published: June 2020

The structure and function of ribosomes, small cellular organelles involved in protein synthesis, are determined by both their macromolecular components - proteins and RNAs. The protein/RNA ratio depends on the evolutionary level of the organism. In eukaryotic ribosomes the protein/RNA ratio is ~ 1:1 (w/w). While the number and composition of ribosomal proteins varies from species to species, the number and composition of RNAs is highly conserved.

We have chosen the 18S and 28S ribosomal RNA isolated from baby hamster kidney cells to study the structural role of eukaryotic RNAs on the ribosome. Similarity in the extent of secondary structure suggests that the eukaryotic RNAs have similar “domain” structure as their prokaryotic counterparts. This structure consists of segments of double stranded stems, single strands and loops. However, folding of these segments into a conformation contributing to the 3-D structure of the ribosome remains to be established.
Initiation of placentation in the pig
Authors: Keys J.L.
Published: June 2020

The microscopic structure of the mature placenta in domesticated species has been described in many publications but the early developmental stages have only been studied in detail within the past decade. The earliest date previously cited for initial attachment of the porcine trophoblast to the maternal epithelium is 14 to 18 days of gestation. This investigation was undertaken to establish morphological changes in the maternal epithelium in preparation for this event.

Four or 5 nulliparous gilts were slaughtered on each of d10 and d13 of the estrous cycle and pregnancy (d0=1st d of estrus), and tissue samples prepared for correlative light and electron microscopy. Samples were compared between gilts on equivalent days of the cycle/pregnancy in order to determine endometrial changes specific to pregnancy. Sites adjacent to embryos were contrasted with those lacking trophoblastic contact within the same animal to investigate whether epithelial adaptations for attachment are localized to trophoblast proximity or represent a generalized uterine response.
Ultrastructure of Melosira resting cell rejuvenation
Authors: Bourne C. E. M. , Sicko-Goad L.
Published: June 2020

Much recent attention has been focused on vegetative survival forms of planktonic diatoms and other algae. There are several reports of extended vegetative survival of the freshwater diatom Melosira in lake sediments. In contrast to those diatoms which form a morphologically distinct resistant spore, Melosira is known to produce physiological resting cells that are indistinguishable in outward morphology from actively growing cells.

We used both light and electron microscopy to document and elucidate the sequence of cytological changes during the transition from resting cells to actively growing cells in a population of Melosira granulata from Douglas Lake, Michigan sediments collected in mid-July of 1983.
Uptake and destruction of intracellular forms ofTrypanosoma cruziby murine macrophages: An ultrastructural study
Authors: Pankratz H. S. , Villalta F. , Kierszenbaum F.
Published: June 2020

Very little is known about the outcome of the interaction of phagocytic cells with the intracellular (amastigote) form ofTrypanosoma cruzi, the causative agent of Chagas’ disease. Work with this form of the parasite has been hampered by the difficulties associated with the isolation of sufficient numbers of undamaged amastigotes from infected host tissues. Because amastigotes are the only forms ofT. cruzicapable of multiplying in mammalian hosts, studies on phagocytic cell interaction withT. cruziamastigotes are relevant to the mechanisms of host defense against and dissemination of the parasite. The recent development in our laboratory of conditions to produceT. cruziamastigotes in axenic ML-15HA medium has rendered it possible to conduct research with this form of the organism.
Microstructures in Beta-III Titanium Alloys
Authors: Fujishiro S.
Published: June 2020

In an effort to increase the elastic modulus of commercial Beta-III Titanium alloy (Ti-12Mo4.5Sn5.5Zr) without impairing other mechanical properties, the alloy has been solutionized in the beta and beta/alpha fields and subsequently aged at the alpha and alpha/omega forming temperature range, following water quench; the volume fraction and morphology of the precipitation phases govern the elastic modulus and other mechanical characteristics. Dilatometric technique was employed to determine the omega forming range which is indicated by a notable contraction; contraction is due to depletion of the Mo content in the beta phase. TEM was utilized in order to identify the phases and define morphology whereas the volume fraction of phases was determined by X-ray.
A Transmission Electron Microscopy Study of Decomposition in the Zn-Al Eutectoid Alloy
Authors: Nuttall K.
Published: June 2020

There has been considerable interest in the Zn-Al eutectoid alloy in recent years mainly because it exhibits superplastic deformation under certain conditions. A feature of particular importance is that the microstructural requirements for superplasticity can be achieved.in this alloy by heat treatment alone. However in spite of this, the mechanisms of phase transformation have not been widely studied; some aspects of these are described in this paper. The eutectoid reaction takes place at a composition of 78 wt% Zn and a temperature of 276°C by the decomposition of the high temperature γ phase (F.C.C.) to the Zn-rich β phase (C.P.H.) and the Al-rich α phase (F.C.C.) terminal solid solutions. Experiments have mainly involved quenching directly from the γ - phase field and isothermally transforming at various temperatures below 276°C.
Tensile Failure of 55-Nitinol Wire
Authors: Grace F. I.
Published: June 2020

An interest in NiTi alloys with near stoichiometric composition (55 NiTi) has intensified since they were found to exhibit a unique mechanical shape memory effect at the Naval Ordnance Laboratory some twelve years ago (thus refered to as NITINOL alloys). Since then, the microstructural mechanisms associated with the shape memory effect have been investigated and several interesting engineering applications have appeared.

The shape memory effect implies that the alloy deformed from an initial shape will spontaneously return to that initial state upon heating. This behavior is reported to be related to a diffusionless shear transformation which takes place between similar but slightly different CsCl type structures.
Scanning Electron Microscopy of Single-Crystal NiO Energetics
Authors: Murr L. E. , Miglionico C.J.
Published: June 2020

The fusion of NiO powder in an oxygen-rich oxy-hydrogen flame at ∼2000°C at atmospheric pressure has been observed to produce, in addition to single-crystal Ni growth, a residual (001) vicinal NiO growth which exhibits an intergrowth and regrowth of isolated particles characterized as equilibrium (regular-faced) polyhedra, and a prominent “negative crystal” phenomena in the vicinal faces of the oxide. Observations of the NiO crystal growth and particle morphologies were made in a JE0L-JSM-50A scanning electron microscope operated at 25 kV in the secondary electron emission mode. The samples were uncoated.

Figure 1(a) shows typically the NiO growth phenomena observed, while Fig. 1(b) illustrates the vicinal-surface growth features schematically. The major structural features can be characterized as terraces, ledges, and kinks, with "negative" growth features related to systematic terrace-atom desorption.
SEM Study of Marine Ferromanganese Micronodules from the Atlantic Ocean
Authors: McKee Thomas R.
Published: June 2020

Recently there has been increased research on deep ocean ferromanganese n odule deposits due to interest in mining them for their Ni, Co and Cu content (up to 1%). In addition to the scattered surficial deposits of nodules (dia > 10 mm) there are also micronodules (dia < 1 mm) which are much more widespread and seldom studied. Several cores sampled for the present study were taken in the abyssal plain and hills region (depth > 5000 m) of the Northwest Atlantic Ocean (obtained 1973 by S.K.A. aboard R/V Conrad cruise R-16). The micronodules were separated by sieving the coarse fraction > 62 μm), which composed up to 10% by dry weight of the surface sediment, decreasing to 1% at depth (9m) and consisting mainly of ferromanganese micronodules with small amounts of quartz and biogenic material. An initial survey has been completed utilizing reflected light microscopy and scanning electron microscopy (JEOL JSM-U3 equipped with an EDAX energy dispersive X-ray spectrometer) in preparation for a more extensive study of the microstructure, mineralogy and chemistry of the micronodules and sediment.
Application of Energy Dispersive X-Ray Analysis to Textile Fibers
Authors: Goynes W. R. , Carra J. H.
Published: June 2020

In development of chemically finished textile products it is advantageous to be able to determine locations of interactions of finish and fiber. Microscopical tests have been developed for this purpose but those showing internal fiber interactions have been largely subjective. Energy dispersive X-ray (EDX) analysis has extended the capability for location of deposited or reacted elemental species from fabric finishes.

Effectiveness and durability of flame-retardant finishes for textile fabrics depend in part on location and distribution of flame-retardant chemicals. Location of the finish within yarn and fiber structures aids in production of the most efficient flame-retardant product and may serve as well for quality control of flame-retardant processes.
On the Feasibility of Quantitative Microchemical Analysis of Thin Metal Foils
Authors: Fraser G. L. , Zaluzec N. J. , Woodhouse J. B. , Sis L. B.
Published: June 2020

Several techniques have been developed for the quantitative microchemical analysis of thin foils. These procedures require that in an alloy AB the measured intensity ratio, IA/IB frora the foil be independent of foil thickness. Cliff and Lorimer find that this condition is met in all cases they have examined whereas Jacobs and Baborovska show data where absorption of longer wavelength X-rays was apparent.

The present study was undertaken to evaluate these procedures for the combination of a scanning transmission electron microscope (JEOL JSEM 200) and an energy dispersive analyzer (Ortec).
Inner Shell Ionization by 60 keV Electrons, Application to Microanalysis
Authors: Kihn Y. , Sevely J. , Jouffrey B.
Published: June 2020

By using a Castaing-Henry filtering device adapted on a Siemens Elmiskop I electron microscope, we have directly observed plasmon and inner shell excitations by 60 keV electrons on electron energy loss spectra. Inner shell excitation edges have been detected up to 1900 eV.

By comparing L and K inner shell excitation profiles in the case of Magnesium, Aluminium and Silicon, it is concluded that the optical selection rules, △1 = ±1, explain the shape of the spectrum after the edge in a first approximation.
An Improved Specimen Mount for Scanning Electron Microscopy
Authors: Lamvik M. K. , Lin S. D.
Published: June 2020

The development of a specimen holder for use without adhesives was originally motivated by the need to maintain an especially clean specimen environment in ion-pumped high vacuum scanning microscopes. Since then, it has become clear that the system is very convenient and inexpensive in everyday use and would be of value in many types of scanning microscopes. We report here some recent improvements in the system.

The design is based on the use of a simple disc as the specimen mount, rather than a more complex shape such as a "stub." Since the disc may be the actual substrate upon which a specimen is obtained, no adhesive is needed to attach the substrate to a mounting stub.