bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reversible Effects of Hyperosmolar Sucrose on Frog Sympathetic Ganglion
Authors: Minker E. , Riker W. K. , Russell N. J. 
Published: June 2020

Saline solutions made hyperosmotic by addition of sucrose increase the discharge frequency of miniature spontaneous junctional potentials at neuromuscular junctions and sympathetic ganglia and can alter structure in both muscle and nerve. Since effects of such solutions on synaptic structure are unknown, we have investigated the influence of hyperosmolarity on function and ultrastructure in synaptic regions of isolated abdominal sympathetic ganglia of the bullfrog, Rana catesbiana.Synaptic transmission was monitored by extracellular recording of postganglionic responses to supramaximal.preganglionic stimulation (0.3 Hz). Ganglia were first equilibrated in normal frog Ringer's solution, then transferred to test solutions, and some ganglia were subsequently returned to normal Ringer's to examine functional and structural recovery.
Electron Microscopy of Virus in L1210V Cells
Authors: Chen Pearl L. , Sarkar Nurul H. , Moore Dan H. 
Published: June 2020

Two cell culture lines established in vitro, L1210VA and L1210VB, were obtained from Dr. Dorris J. Hutchison, Sloan- Kettering Cancer Research Institute, Rye, N. Y. They were maintained in Earl'-Eagle' medium containing a double dose of glutamine.The original lymphatic leukemia L1210 was induced by Law et al in a DBA/2 female mouse. In these cells grown intraperitoneally in DBA mice the presence of intracytoplasmic A particles and their incorporation into budding virions, as well as extracellular particles with the morphology of leukemiasarcoma viruses have been described. Since the intracytoplasmic A particles are related to the development of B particles it was our interest to investigate whether or not the cells produce B particles.
Homologs of Leydig and Sertoli Cells in the Testis of the Teleost, Oryzias Latipes
Authors: Gresik Edward W. 
Published: June 2020

The testis of O. latipes is composed of cysts containing germinal elements Tn various stages of spermatogenesis (Fig. 1). The simple epithelial cells of the cyst wall are the Sertoli cell (SC) homologs. When the contained germinal elements have matured, the cyst epithelium fuses with that of the terminal divisions of the efferent duct system. In the connective tissue stroma surrounding the cysts and ducts, the Leydig cell (LC) homologs are found.The LC (Fig. 2) contains a central vesicular nucleus with a distinct nucleolus. Flattened cisternae of rough ER are distributed throughout the cytoplasm; smooth ER, usual in steroidogenic cells, is not present.
Ultrastructure of the Mongolian Gerbil Spermatozoa
Authors: Majumdar S. K. , Thomas T. S. 
Published: June 2020

With the recent broadening of the study of fertilization in vitro and in vivo, the importance of spermatozoon ultrastructure has been greatly emphasized. A great deal of research has been conducted with mammalian spermatozoa. However, no information is available on the Mongolian gerbil (Meriones unguiculatus). Small blocks of testis and epididymis of mature males were fixed in 4% glutaraldehyde and post-fixed in 1% osmium tetroxide adiusted to pH 7.2 with 0.1 M sodium cacodylate. After dehydration, the tissues were embedded in Epon. Sections were cut with glass knives on a Porter-Blum ultramicrotome stained with uranyl acetate-lead-citrate, and examined with an RCA EMU-3G electron microscope.The head of the Mongolian gerbil is falciform and contains a nucleus, an acrosome, and membranous envelopes (Figs. 1 & 7).
A Study on the Fine Structure of the Lateral Line Organ of the Sea Eel
Authors: Hama K. 
Published: June 2020

The lateral line organs of the sea eel consist of canal and pit organs which are different in function. The former is a low frequency vibration detector whereas the latter functions as an ion receptor as well as a mechano receptor.The fine structure of the sensory epithelia of both organs were studied by means of ordinary transmission electron microscope, high voltage electron microscope and of surface scanning electron microscope.The sensory cells of the canal organ are polarized in front-caudal direction and those of the pit organ are polarized in dorso-ventral direction. The sensory epithelia of both organs have thinner surface coats compared to the surrounding ordinary epithelial cells, which have very thick fuzzy coatings on the apical surface.
An Ultrastructural Study of the Lateral Vestibular Nucleus in the Rat: Changes in Glial Cells Following Partial Deafferentation
Authors: Johnson J. E. 
Published: June 2020

Mori and Leblond have reported that oligodendrocytes in the corpus callosum of rats may be classified into three types consisting of light, medium and dark. The light oligodendrocytes are the largest, and the dark ones are the smallest. In the present study, oligodendrocytes of different sizes and densities were found to occur in the normal lateral vestibular nucleus of the rat. Here, as reported in the corpus callosum, the darkest cells are the smallest. The largest of the oligodendrocytes in the lateral vestibular nucleus have a density which approaches that of astrocytes, which are also present throughout the nucleus.The lateral vestibular nuclei of 18 rats were partially deaffer-entated by aspirating the anterior vermis of the cerebellum, from which the nucleus receives input.
Combined elemental and structural imaging in a computer contrlled analytical electron microscope
Authors: Leapman R. D. , Fiori C. E. , Gorlen K. E. , Gibson C. C. , Swyt C. R. 
Published: June 2020

The modern analytical electron microscope incorporates a scanning transmission (STEM) capability together with a variety of detectors for signals resulting from the interaction of the electron probe with the sample. Information about both the elemental composition and morphology of the sample is available. The images derived from STEM signals can be readily digitized, thus allowing precise numerical processing of the data. Since several signals may be recorded concurrently one pixel at at time, the corresponding images are in registration and may be overlaid for comparison or combined for example to give the ratio of two elements. Such composite images can be expected to provide more information than each separately.The large amount of data which has to be processed in the acquisition of a digitized image requires a considerable amount of computer hardware and software. The system developed at NIH for application in biology has been described by Gorlen et al. and Fiori et al. and is outlined in Fig. 1. A Digital Equipment Corporation PDP 11/60 computer with an LSI 11/23 satellite computer is interfaced to a Hitachi H700H TEM-STEM with a magnetic sector electron energy loss spectrometer (EELS), one Kevex top-looking energy dispersive x-ray detector and one Tracor Northern side-looking detector; these provide the analytical signals with digital output.
Hot stage study of γ →α Al2O3 transformations
Authors: Tucker Dennis , Kenik E. A. , Hren John 
Published: June 2020

It has been observed in spherical A12O3 particles precipitated from sulfate solution that polycrystalline γ-Al2O3 forms at 900°C in air during calcination. Further heating brings about the transformation to single crystal α-Al2O3 particles at approximately 1100°C. This behavior has also been observed by other authors for the γ→α Al2O3 transformation. In order to determine the nucleation sites and trie general growth characteristics of these 1-10 μm diameter particles, it was decided to study the transformation in situ in a HVEM*.Powders were prepared after the method of Onoda and Curreri and placed on tungsten grids with a thin Pt film substrate. The powders were then heated in situ in a 1 meV microscope* equipped with a single tilt hot stage capable of achieving 1250°C and a residual gas analyzer.
Atomic structure of ion-implantation produced amorphous silicon and amorphous-crystalline interface structure and kinetics
Authors: Narayan J. , Fathy D. 
Published: June 2020

The structure of amorphous silicon determines its physical properties ranging from crystallization kinetics to efficiency of solar cells. One point of particular interest has been the existance of microcrystallites in the amorphous phase. Different crystallization kinetics are obtained for purely amorphous silicon and for amorphous silicon having a trace of crystallinity. The incorporation of dopants into substitutional sites after solid-phase crystallization has been also found to be affected by the degree of amorphousness.The purpose of this investigation was two fold: first, to characterize the structure of amorphous silicon, and second to study the structure of amorphous-crystalline interface. The importance of these two factors in the crystallization phenomena is discussed.
Cathodoluminescence microanalysis of semiconductors: Potential and limits
Authors: Löhnert K. , Kubalek E. 
Published: June 2020

The potential of the cathodoluminescence (CL) technique in the SEM or STEM for the investigation of semiconducting materials and devices is based on the fact, that it enables the evaluation of inhomogeneities in electronic material properties on a micron scale. Full use of this potential can be only made, however, if the experimental setup is useful not only for the measurement of the integral (undispersed) CL but also for spectral, temporal and temperature-dependent analysis. These requirements are not met with commercial electron beam instruments and therefore suited equipment has to be provided and assembled by the user (for detailed information on the most advanced experimental arrangements see /1,2/).The three primary quantities then available for analysis are a) the CL intensity, b) the CL spectrum and c) the CL decay after pulse excitation, which will be dealt with in the same sequence.
High-resolution structure determination by ALCHEMI
Authors: Self Peter G. , Buseck Peter R. 
Published: June 2020

ALCHEMI (Atom Location by CHanneling Enhanced Microanalysis) enables the site occupancy of atoms in single crystals to be determined. In this article the fundamentals of the method for both EDS and EELS will be discussed. Unlike HRTEM, ALCHEMI does not place stringent resolution requirements on the microscope and, because EDS clearly distinguishes between elements of similar atomic number, it can offer some advantages over HRTEM. It does however, place certain constraints on the crystal. These constraints are: a) the sites of interest must lie on alternate crystallographic planes, b) the projected charge density on the alternate planes must be significantly different, and c) there must be at least one atomic species that lies solely on one of the planes.An electron beam incident on a crystal undergoes elastic scattering; in reciprocal space this is seen as a diffraction pattern and in real space this is a modulation of the electron current across the unit cell. When diffraction is strong (i.e., when the crystal is oriented near to the Bragg angle of a low-order reflection) the electron current at one point in the unit cell will differ significantly from that at another point.
An AEM study of phosphorus segregation in a stainless steel
Authors: Pelton A. R. , Westmacott K. H. 
Published: June 2020

The deleterious effects on the mechanical properties of phosphorus segregation to grain boundaries in ferritic alloys are well documented in the metallurgical literature. An understanding of this recurring problem has profited from the recent application of analytical electron microscopy (AEM). EDS analysis has allowed the detection of phosphorus in thin films at prior austenite grain boundaries and in association with intergranular carbides. Although austenitic alloys also suffer from property degradation due to segregated impurity elements, comparable studies have not been conducted on these materials. The purpose of this paper, therefore, is to report the results from an AEM investigation of phosphorus segregation in an austenitic stainless steel. Of particular concern is the effect of grain boundary type on phosphorus segregation and precipitation.An Fe-18 Cr-10 Ni-0.3P (weight percent) steel was quenched from 1150°C and aged between 400-700°C. Samples were prepared by standard polishing techniques; those samples analyzed by EDS were lightly ion-beam milled to remove surface films formed by the electropolishing.
NiAl precipitation in Fe-12w/o Cr-5w/o Ni-4w/o Al
Authors: Murr L.E. , Dunning J.S. , Shankar S. 
Published: June 2020

Aluminum additions to conventional 18Cr-8Ni austenitic stainless steel compositions impart excellent resistance to high sulfur environments. However, problems are typically encountered with aluminum additions above about 1% due to embrittlement caused by aluminum in solid solution and the precipitation of NiAl. Consequently, little use has been made of aluminum alloy additions to stainless steels for use in sulfur or H2S environments in the chemical industry, energy conversion or generation, and mineral processing, for example.A research program at the Albany Research Center has concentrated on the development of a wrought alloy composition with as low a chromium content as possible, with the idea of developing a low-chromium substitute for 310 stainless steel (25Cr-20Ni) which is often used in high-sulfur environments. On the basis of workability and microstructural studies involving optical metallography on 100g button ingots soaked at 700°C and air-cooled, a low-alloy composition Fe-12Cr-5Ni-4Al (in wt %) was selected for scale up and property evaluation.
The oxidation of Inconel alloy MA754 at low oxidation potential
Authors: Braski D. N. , Goodell P. D. , Cathcart J. V. , Kane R. H. 
Published: June 2020

It has been known for some time that the addition of small oxide particles to an 80 Ni—20 Cr alloy not only increases its elevated-temperature strength, but also markedly improves its resistance to oxidation. The mechanism by which the oxide dispersoid enhances the oxidation resistance is being studied collaboratively by ORNL and INCO Alloy Products Company.Initial experiments were performed using INCONEL alloy MA754, which is nominally: 78 Ni, 20 Cr, 0.05 C, 0.3 Al, 0.5 Ti, 1.0 Fe, and 0.6 Y2O3 (wt %).Small disks (3 mm diam × 0.38 mm thick) were cut from MA754 plate stock and prepared with two different surface conditions. The first was prepared by mechanically polishing one side of a disk through 0.5 μm diamond on a syntron polisher while the second used an additional sulfuric acid-methanol electropolishing treatment to remove the cold-worked surface layer. Disks having both surface treatments were oxidized in a radiantly heated furnace for 30 s at 1000°C. Three different environments were investigated: hydrogen with nominal dew points of 0°C, —25°C, and —55°C. The oxide particles and films were examined in TEM by using extraction replicas (carbon) and by backpolishing to the oxide/metal interface. The particles were analyzed by EDS and SAD.
Analytical electron microscopy of aluminum ion-implanted with molybdenum
Authors: Stephenson L. D. , Bentley J. , Benson R. B. , Parrish P. A. 
Published: June 2020

The microstructures of aluminum ion-implanted with molybdenum and subjected to various heat treatments are being investigated for correlation with nearsurface properties such as corrosion. Previous work indicated enhanced corrosion resistance, but dealt chiefly with the as-implanted condition and involved little microstructural characterization. In addition, the Al-Mo binary system is of interest because metastable phase formation was considered to be possible and the equilibrium phase diagram is poorly defined. Electropolished coupons 38 × 28 × 0.5 mm of 99.999% A1 with ∽0.5 mm grain size were implanted with Mo+ ions at the Naval Research Laboratory. The dual energy implant schedule of 4.88 × 1019 ions/m2 at 50 keV plus 6.14 × 1019 ions/m2 at 110 keV resulted in a peak concentration of 4.4 at. % Mo (measured by ion backscattering) within the projected range of ∽50 nm.Disks (3 imi diam) were electrodischarge machined from as-implanted specimens and then were backthinned by electropolishing.
Analytical electron microscopy of supported bismuth molybdate catalysts
Authors: Kolar H.R. , Carpenter R.W. 
Published: June 2020

Three major phases of bismuth molybdate are commonly used as selective oxidation catalysts: Bi2Mo3O12(α), Bi2Mo2O9(β) and Bi2MoO6(γ). The distribution of phases and microstructural configuration is of great interest as the phases are often mixed to produce particular catalytic properties.Two samples of Bi2Mo3O12(α) supported on SiO2 were examined in a Philips EM400ST (Cs=1.5mm) at 100kV with a field emission source and EDAX energy dispersive x-ray spectrometer. The samples were prepared from Bi(NO3)3 and amonium molybdate with the pH adjusted to 5. Ludox was added to obtain a yield of 1:1 Bi2Mo3O12 to SiO2 and the samples were spray dried. The samples were then calcined in air at 550°c and 650°C (A and B respectively). After suspension in acetone and crushing in a mortar and pestle the samples were dispersed onto a holey carbon film on Cu grids. EDS spectra were obtained with a focussed probe of approximately 15Å diameter (measure) in the STEM mode. A Gatan low background, low temperature stage (T-185°C) was used to reduce contamination. Acquisition times of 150s were used to obtain reasonable counting statistics.
On-line Fourier analysis of electron-microscope images using electronic apertures
Authors: Krakow William 
Published: June 2020

In recent years digital television frame store devices have made it possible to digitze high resolution TEM images directly and obtain their Fourier transforms (i.e. optical transforms) in real time.1-3 Generally, restricted areas of 64x64 pixels are processed to reduce computer overhead hence the resultant optical transforms suffer from speckle due to the finite sampling. A larger array size of 256x256 has been attempted4 but the computation time to obtain the FFT was probably greater than ten minutes or done off-line. More efficient and extensive computer methods have been developed in our laboratory for flexible, real time, Fourier analysis via a digital TV frame store which will now be described.The facilities of the digital frame store are described elsewhere in this proceedings. A JEOL 200CX top entry pole piece microscope was coupled through a transmission to a low light level SIT camera having a true 512x512 pixel resolution and provided input to the frame store. The problem of Fourier analysis then reduces to methods of digitizing data, transmitting it to the host computer, manipulating and processing data in the host and displaying final results by shipping da ta back to the frame store from the host computer for display.
Overlapping SAD patterns
Authors: Ploc R.A. 
Published: June 2020

Most computer techniques used to index Selected Area electron Diffraction (SAD) patterns deal with simple patterns in the sense of there being present a single linear array of two reciprocal lattice vectors. If more than one crystal orientation contributes to the pattern, the investigator must judiciously pick and choose pairs of reflections (or groups of reflections if measuring errors are to be minimized) in an effort to sort out which reflections belong to what orientation. Even further complicating the issue is the usual desire to establish the orientational relationship between the different diffracting materials. These problems have been addressed at our laboratories by creating a computer code to isolate and identify overlapping SAD patterns.The basis of our analysis rests upon the fact that each crystal orientation giving rise to an SAD pattern is but a twodimensional sectioning of a much larger three-dimensional reciprocal lattice. At 100 keV operation, the reciprocal lattice vectors associated with each reflection are, to a good approximation, parallel to the vector from the diffraction pattern origin to the reflection in question.
Three-D structure of luminal plasma membrane protein from urinary bladder
Authors: Wade R.H. , Brisson A. 
Published: June 2020

We present a low resolution (35 Å) three dimensional reconstruction of the molecular form of the membrane protein which forms the naturally occuring crystalline arrays of the luminal plasma membrane of the mammalian urinary bladder.This membrane consists of concave plaques 120 Å thick with 80 Å thick interplaque regions, giving the scalloped appearance observed on thin sections. Isolated luminal membranes, observed by negative staining and freeze etching present reqular hexagonal arrays of particles with a lattice parameter of 160 Å. Image averaging techniques show that the particles possess 6 or 12 resolvable subunits having a stellate appearance. These arrays called hexagonal membranes correspond to the 120 Å thick concave plaques. Thin sections show the hexagonal membrane to be asymmetric,with a 80 Å thick luminal leaflet and a 40 Å thick cytoplasmic leaflet.The isolation procedure described by Caruthers and Bonneville was followed with slight modifications. 1 % PTA (pH 7.0-7.4) was used as negative stain.
Vaginal microflora in a rat model of polycystic ovarian disease
Authors: Singh K.B. , Tewari Ram P. , Khosho F. K. 
Published: June 2020

Exposure of female rats to continuous light for prolonged periods induces persistent estrus (PE), an anovulatory disorder. Instead of cyclic fluctuations, the vaginal smears from PE rats show only cornified cells as the hormonal control of the estrous cycle becomes inappropriate, and ovaries become cystic when ovulation ceases. The reproductive tract, a key target organ in PE, shows numerous manifestations of chronic estrogenic influence.In this paper, we report our findings on bacterial colonizations and ultrastructural examinations of the vaginal surface epithelium of PE rats with polycystic ovaries (PCO). Quantitation of bacteria in the vaginal lavage was done with a standard volume of sterile normal saline and studied in five different hormonal states: diestrus day 1 (D-1), diestrus day 2 (D2), proestrus (Pro E), estrus (E), and persistent estrus (PE). Scanning electron microscopy (SEM) was used to examine the vaginal surface epithelium from PE rats with PCO and compared to the controls. In all rats, cardiovascular perfusion was performed for in vivo fixation of the organs using 2.5% glutaraldehyde in 0.1 M Na Cacodylate buffer (pH 7.3) for 30 minutes.
The use of Lab-Tek tissue culture Chamber/ Slides and Flaskette for processing cultured monolayers for electron microscopy
Authors: Chien K. , Van De Velde R.L. , Heusser R.C. , Said J.W. 
Published: June 2020

In situ embedding is a preferable means for the ultrastructural study of cultured cell monolayers. However, the major difficulty is the separation of the polymerized plastic resin from the supporting substrates. This abstract demonstrates a simple, fast procedure for using existing products for cell culture and in situ embedding of monolayers. Epoxy block surfaces up to 10 cm2 can be easily separated from an untreated glass slide and sectioned vertically or horizontally for EM studies.The Lab-Tek tissue culture Chamber/Slides or Flaskette are constructed so that 1 to 8 chamber compartments or a single flask is attached to a regular glass slide by gaskets. Different cell lines or procedures can be performed on the same chamber/slide. When the plastic chambers and gasket are removed, the glass slide can be coverslipped and filed for reference. We use these products routinely for cell cultures. When an EM study is needed, we fix the cell monolayers in situ within the chambers or flask, dehydrate with ethanol, infiltrate and embed in an epoxy resin.