bluuebunny/crossref_metadata_2025_split huggingface dataset:
SEM Characterization of Aged Coal Liquefaction Catalysts
Authors: Freeman G. B. , Heink J. B. , Davis B. H. 
Published: June 2020

Coal liquefaction was identified as a national priority in the midseventies, Nonetheless, it was clear that oil is a limited resource and that the energy potential of this country's coal resources must be tapped in an efficient and environmentally sound manner. Coal liquefaction is essentially the thermal process of bond breaking and, if direct coal liquefaction is to succeed as a viable technology, yields must be improved by the use of selective catalysis.While supported CoMo catalysts have been used routinely for hydrodesulfurization (HDS) in the petroleum industry, the environment of coal liquefaction is significantly more severe. Deactivation of the Mo or W and Ni or Co catalysts in coal liquefaction is quite rapid and is thought to be caused by a combination of coke formation (closing off catalyst pore structure), mineral deposition and catalyst sintering.
A Review on Colloidal Gold Post-Embedding Cytochemical Techniques
Authors: Bendayan Moïse 
Published: June 2020

In 1971, colloidal gold was introduced in immunocytochemistry by Faulk and Taylor for the ultrastructural demonstration of antigenic sites at the surface of bacteria. Since then, application of this marker has been growing rapidly, extending its use to the various fields of cytochemistry. Indeed, it has been applied for pre- and post-embedding labeling of cell surface and intracellular binding sites respectively. It has been used in light microscopy as well as in both transmission and scanning electron microscopy, and thus appears today as the marker of choice in cytochemistry.The present short review means to illustrate four different affinity techniques, which have been developed recently for the ultrastructural postembedding localization of various macromolecules using colloidal gold as the electron dense marker.
In Vitro Root Caries: Hexamethyldisilazane Treatment For SEM
Authors: Chan D.C.N. , Wefel J.S. , Dogan Umran 
Published: June 2020

Characterization of in vivo and in vitro root caries systems have traditionally been carried out with transmitted light microscopy, polarized light microscopy and microradiography. Electron microscopy and probe analysis will provide additional information regarding the morphological and chemical features of sound and carious dentin-cemental surfaces. Of equal importance is the correlation of E.M. observations to that ovtained by light microscopy and microradiographic techniques.Previous E.M. investigations of early carious cementum showed a characteristic cross-striations of collagen fibers in sound cemental matrix. These striations were observed to be partially or completely lost in cemental lesions. Another study suggested that the breakdown of the major portion of the collagen occurred late or was the final step in the destructive phase of the carious process.
Conformation of Free Ribosomal RNAs by STEM and Wet Film Technique as a Phylogenetic Probe
Authors: Oostergetel G.T. , Wall J.S. , Hainfeld J.F. , Boublik M. 
Published: June 2020

The similarity of ribosomes involvement in protein synthesis in evolutionarily distant species makes this cellular organelle an attractive phylogenetic probe. The evolutionary changes in ribosomes are reflected not only in the morphology of the ribosome but also in the composition and structure of its components - proteins and RNAs.We have investigated the extent of structural similarity of free rRNAs from baby hamster kidney (BHK) cells and Escherichia coli as examples of RNAs from a eukaryote and a prokaryote, respectively. Using dedicated STEM and “wet film” technique (Wall et al. these Proceedings) for specimen deposition we have improved considerably the resolution of RNA conformation in comparison to the glow discharge technique. A gallery of individual unstained freeze-dried 28S RNA molecules Isolated from the large (60S) ribosomal subunits from BHK cells, obtained by deposition from distilled water, is presented in Fig. 1a.
Endoplasmic Reticulum Specializations in Aging Hamster Neurons
Authors: Tank Buschmann MB. 
Published: June 2020

Rough endoplasmic reticulum has been observed in specialized forms, including the lamellar body (LB) the subsurface cistern (SSC) and a combination of the two known as the lamellar body/sursurface cistern (LB/SSC, Fig. 1) complex. These structures have been described in the neurons of various developing and adult mammals. However, there are no published quantitative reports of these endoplasmic reticulum specializations (ERS) over the life span of a species. In this investigation, quantitative changes were studied in 15- (immature), 100-, 500-(mature), 600- and 700-day (aged) postnatal pyramidal neurons in the frontal cortex of golden hamsters (Mescricetus auratus).The anesthetized animals were perfused with glutaraldehyde-paraformaldhyde in sodium cacodylate buffer (pH 7.3) after the method of Peters. Tissue samples were post-fixed in 2% osmium tetroxide, dehydrated in acetone and embedded in Epon-Araldite resin. Lengths were obtained with the BioQuant Image Analyzer (R & M Biometrics, Nashville, TN).
Tobacco Mosaic Virus-Infected Tissue
Authors: Henry Egbert W. 
Published: June 2020

Tobacco mosaic virus (TMV) infection has been studied in several investigations of Nicotiana tabacum leaf tissue. Earlier studies have suggested that TMV infection does not have precise infective selectivity vs. specific types of tissues. Also, such tissue conditions as vein banding, vein clearing, liquification and suberization may result from causes other than direct TMV infection. At the present time, it is thought that the plasmodesmata, ectodesmata and perhaps the plasmodesmata of the basal septum may represent the actual or more precise sites of TMV infection.TMV infection has been implicated in elevated levels of oxidative metabolism; also, TMV infection may have a major role in host resistance vs. concentration levels of phenolic-type enzymes. Therefore, enzymes such as polyphenol oxidase, peroxidase and phenylalamine ammonia-lyase may show an increase in activity in response to TMV infection. It has been reported that TMV infection may cause a decrease in o-dihydric phenols (chlorogenic acid) in some tissues.
Scanning Electron Microscopy of Staphylococcus Epidermidis Adherence to Continuous Ambulatory Peritoneal Dialysis Catheters
Authors: Lamoreaux William J. , Smalley David L. , Baddour Larry M. , Kraus Alfred P. 
Published: June 2020

Infections associated with the use of intravascular devices have been documented and have been reported to be related to duration of catheter usage. Recently, Eaton et al. reported that Staphylococcus epidermidis may attach to silastic catheters used in continuous ambulatory peritoneal dialysis (CAPD) treatment. The following study presents findings using scanning electron microscopy (SEM) of S. epidermidis adherence to silastic catheters in an in vitro model. In addition, sections of polyvinyl chloride (PVC) dialysis bags were also evaluated by SEM.The S. epidermidis strain RP62A which had been obtained in a previous outbreak of coagulase-negative staphylococcal sepsis at local hospitals was used in these experiments. The strain produced surface slime on exposure to glucose, whereas a nonadherent variant RP62A-NA, which was also used in these studies, failed to produce slime. Strains were grown overnight on blood agar plates at 37°C, harvested from the surface and resuspended in sterile saline (0.85%), centrifuged (3,000 rpm for 10 minutes) and then washed twice in 0.1 M phosphate-buffered saline at pH 7.0. Organisms were resuspended at a concentration of ca. 106 CFU/ml in: a) sterile unused dianeal at 4.25% dextrose, b) sterile unused dianeal at 1.5% dextrose, c) sterile used dialysate previously containing 4.25% dextrose taken from a CAPD patient, and d) sterile used dialysate previously containing 1.5% dextrose taken from a CAPD patient.
Ultrastructure of Equine Mast Cells in Bronchoalveolar Lavage and Lung
Authors: Yamashiro S. , Bast T. , Viel L. , Harris W. 
Published: June 2020

Examination of the cells in the bronchoalveolar lavage is frequently used for the evaluation of inflammatory lesions of the lower airways and alveoli. Identification of the cells in the lavage is important for differential counts. It has been shown that human mast cells and basophils exhibited similar morphological and histochemical features at light microscopic level and they were collectively called basophiloid cells. Dvorak et al have reviewed the ultrastructural characteristics of these cells in humans, guinea pigs and mice but no such study has been done on horses.Bronchoalveolar washings collected from three adult geldings were centrifuged in Wintrobe tubes, followed by the fixation in 2.5% glutaraldehyde in 1.0 M phosphate buffer at pH 7.2. The samples were post-fixed in 2.0% osmium tetroxide in the phosphate buffer and embedded in Epon 812. Small pieces of lung tissues from three adult, normal horses were also processed for transmission electron microscopy (TEM). In addition, blood samples from two adult horses were processed for TEM.
Hepatic Ultrastructure and Biochemistry Following Insulin Withdrawal
Authors: Garfield S.A. , Fellows M.F. , Cardell R.R. 
Published: June 2020

This study examines the hepatic ultrastructural and biochemical responses following insulin withdrawal from insulin-maintained streptozotocin- diabetic rats. This hormonal manipulation permitted analysis of the hepatocellular events occurring during diabetic onset. Normoglycemia was maintained in the induced diabetic rats for seven days with daily injections of 5 U intermediate acting insulin (NPH-Iletin) per 100 gram body weight. This was followed by treatment for 24 hr with regular short acting insulin at 6 hr intervals (2.5 U/100 gr b.w.).Animals were sacrificed at intervals following the last insulin injection. Plasma was collected for glucose and insulin determinations. Liver samples were prepared for ultrastructural analysis or were collected for Isolation of rough and smooth endoplasmic reticulum fractions (RER, SER). Isolated RER and SER membrane preparations were analyzed for glucose-6-phosphatase (G-6-Pase) activity, as well as for phospholipid, cholesterol, and fatty acid composition.
Identification of Maize Rayado Fino Virus by Immunoelectron Microscopy
Authors: Bradfute O. E. 
Published: June 2020

Maize rayado fino virus (MRFV) causes a severe disease of corn (Zea mays) in many locations throughout the neotropics and as far north as southern U.S. MRFV particles detected by direct electron microscopy of negatively stained sap from infected leaves are not necessarily distinguishable from many other small isometric viruses infecting plants (Fig. 1).Immunosorbent trapping of virus particles on antibody-coated grids and the antibody coating or decoration of trapped virus particles, was used to confirm the identification of MRFV. Antiserum to MRFV was supplied by R. Gamez (Centro de Investigacion en Biologia Celular y Molecular, Universidad de Costa Rica, Ciudad Universitaria, Costa Rica).Virus particles, appearing as a continuous lawn, were trapped on grids coated with MRFV antiserum (Fig. 2-4). In contrast, virus particles were infrequently found on grids not exposed to antiserum or grids coated with normal rabbit serum (similar to Fig. 1). In Fig. 3, the appearance of the virus particles (isometric morphology, 30 nm diameter, stain penetration of some particles, and morphological subunits in other particles) is characteristic of negatively stained MRFV particles. Decoration or coating of these particles with MRFV antiserum confirms their identification as MRFV (Fig. 4).
The Effects of Estradiol on Chronically Damaged Human Fallopian Tubes: A SEM Study
Authors: Toledo A. , Stoelk G. , Yussman M. , Apkarian R.P. 
Published: June 2020

Today it is estimated that one of every three women in the U.S. will have problems achieving pregnancy. 20-30% of these women will have some form of oviductal problems as the etiology of their infertility. Chronically damaged oviducts present problems with loss of both ciliary and microvillar epithelial cell surfaces. Estradiol is known to influence cyclic patterns in secretory cell microvilli and tubal ciliogenesis, The purpose of this study was to assess whether estrogen therapy could stimulate ciliogenesis in chronically damaged human fallopian tubes.Tissues from large hydrosalpinges were obtained from six women undergoing tuboplastic repair while in the early proliferative phase of fheir menstrual cycle. In each case the damaged tissue was rinsed in heparinized Ringers-lactate and quartered.
Ultrastructural Characteristics of Vaginal Epithelium of Persistent Estrous Rats
Authors: Francis K. Khosho , Robert C. Kaufmann , Kofi S. Amankwah 
Published: June 2020

Adult female rats exposed to constant light will develop anovulatory acyclicity characterized by persistent vaginal cornification (PE) and formation of multiple large cystic follicles on the ovaries. The purpose of the present communication is to describe the ultrastructural changes in vaginal epithelia in PE rats as compared to that in normal estrous rats.Persistent vaginal estrous with PCO was induced in a group of Sprague-Dawely rats by exposure to constant light for 50-150 days. Rats in normal estrous, as determined by vaginal smears, were used as controls. Nembutal- anethesized rats were perfused through the aorta with 2.5% gluteraldehyde in 1M sodium cacodylate buffer (pH 7.3). The mucosa of the vaginal folds just inferior to the cervix were dissected by microsurgery, postfixed, stained with 0.5% ruthenium red in 1% osmium tetroxide, dehydrated, and embedded in polybed. Thick sections (1μ) were stained with toludine blue for light microscopy studies. Thin sections were stained with uranyl acetate and lead citrate.
Ultrastructure of the Spermatophore of a Mealworm Beetle
Authors: Bricker C.S. , Happ G.M. 
Published: June 2020

The male mealworm beetle, Tenebrio molitor, transfers sperm to the female by means of a spermatophore, or sperm sac. This study was undertaken to determine the ultrastructure of the spermatophore and the origins of its components.For ultrastructural studies spermatophores were fixed in 3% glutaraldehyde in 0.1 M phosphate buffer, pH 7.2, post-fixed in OsO4,, dehydrated in ethanol and embedded in Spurrs resin. Silver sections were cut on a Reichert Om U2 microtome, stained with uranyl acetate and lead citrate, and examined in a Philips 201 microscope at 60kV.The spermatophore is an elongate sac composed of an inner cylinder within an outer wall. A lumen is located between the outer wall and cylinder, and contains sperm and secretory products from the TAGs (a pair of tubularshaped reproductive accessory glands). The outer wall consists of 4 or 5 concentric layers formed by the secretory products from the paired beanshaped accessory glands (BAGs). The cylinder contains the same layers as the outer wall, but in a reversed order of location, plus a central core which is a mixture of different products and possibly cell debris (Fig. 1).
A Comparison Between Sterological Point Counting and Digitizing Tablets
Authors: Basgen John M. , Ellis Eileen N. , Michael Mauer S. , Steffes Michael W. 
Published: June 2020

To determine the efficiency of methods of quantitation of the volume density of components within kidney biopsies, techniques involving a semi-automatic digitizing tablet and stereological point counting were compared.Volume density (Vv) is a parameter reflecting the volume of a component to the volume that contains the component, e.g., the fraction of cell volume that is made up of mitochondrial volume. The units of Vv are μm3 /μm3.Kidney biopsies from 15 patients were used. Five were donor biopsies performed at the time of kidney transplantation (patients 1-5, TABLE 1) and were considered normal kidney tissue. The remaining biopsies were obtained from diabetic patients with a spectrum of diabetic kidney lesions. The biopsy specimens were fixed and embedded according to routine electron microscogy protocols. Three glomeruli from each patient were selected randomly for electron microscopy. An average of 12 unbiased and systematic micrographs were obtained from each glomerulus and printed at a final magnification of x18,000.
Lamellar microstructure of discontinuous precipitation reaction front in Cu-7.5%In
Authors: Solorzano I. G. , Audier M. 
Published: June 2020

There is an increasing body of evidence for discontinuous precipitation (DP) as a general solid state phase transformation in materials. The understanding of the DP phenomenon, however, requires to establish its energy balance. The lamellar microstructure at the grain boundary reaction front (RF) is of particular interest since it results from the optimization of, at least, chemical, capillary and interfacial energy terms coupled with the boundary mobility at a given undercooling. Our investigation into this field has lead us to the conclusion that an additional term reflecting the residual stresses in the transformed product should be incorporated. In the present paper, microstructural features focused at the lamellar growth front are illustrated and discussed supporting the idea that DP is a non-equilibrium reaction.The alloy used for this study, Cu-7.5at.%In, was prepared at the Max-Planck-Institut, Stuttgart, from high purity components by induction melting under argon atmosphere and chill cast. After homogenization at 600°C/300h samples were directly aged isothermally at different temperatures and quenched. The parent FCC matrix α decomposes into depleted α lamellae and tetragonal Cu3In β lamellar precipitates.
New detection system for HAADE and holography in STEM
Authors: Mankos Marian , Wang Shi Yao , Weiss J.K. , Cowley J.M. 
Published: June 2020

A novel detection system has been designed and realized experimentally on the HB5 STEM instrument. Shadow images, diffraction patterns as well as high-angle annular dark field and bright field images are observed simultaneously with high efficiency using CCD and TV cameras. The microscope can be operated in a wide range of instrument modes which includes the implementation of new techniques for high resolution imaging.As shown in Fig. 1, the detection system has three triple choice stages. Diffracted beams can be collected by three P47 fast phosphor annular detectors inclined at 45 degree to the axis and having different inner and outer acceptance angles, which can be adjusted by the postspecimen lenses. The detector is observed through a window by a photomultiplier. The annular detectors have been used also for a new bright field STEM technique which utilizes the inner rim of the detectors to collect only the outermost annular part of the central beam and promises an improvement in resolution by a factor of about 1.6. Initial results show some promise (Fig. 2). The transmitted beam is then converted into a light signal in YAG and P47 detectors; optionally the central part of the beam can be detected in the EELS spectrometer. The generated light signal is reflected through a system of mirrors, exits the vacuum chamber and is collected with high efficiency by high aperture optical lenses.
Test of a method for phase retrieval in HREM
Authors: Beeching M.J. , Spargo A.E.C. 
Published: June 2020

1. IntroductionSeveral methods of phase retrieval from HRTEM image intensity distributions have been proposed but no standard method has emerged. We report on the results achieved using a technique based on a development of the “focus variation method”. The dependence of the retrieved wavefunction on various experimental parameters is investigated and the method tested using computer simulated images. The method is shown to be useful in finding the complex wavefield at the exit surface of the specimen, but the relationship of this to the specimen structure is left as a seperate problem.
Preparation and examination of Y-Ba-Cu-O wire sections
Authors: Zanota A. , Perry D. , Kvam E.P. , Balkin D. , McGinnt P. 
Published: June 2020

The electrical properties of directionally solidified YBa2Cu3O7 wires have been shown to be as good as or better than any other bulk-form materials in many situations. However, the microstructural defects, including subgrain, stacking fault, and dislocation contents of these materials have not been well-characterized, in part because of the difficulty of preparing specimens for TEM examination.A new technique has been developed to prepare these wires for TEM examination. The wires were less then .7mm in diameter, making handling of cross-sections difficult. Further, adhesion of evaporated films, electroplated films,and epoxies to the wires was so poor that the wire sections would either shed the films completely, or fall out of the epoxy even when several hundred microns thick. To avoid this problem, a coating technique which adhered tightly to the wire surface was needed.
Fluorescence microscopy of molecular organization and dynamics in cultured cells
Authors: Wang Yu-li 
Published: June 2020

Over the past ten years various technical advances have allowed the direct study of molecular activities in cultured cells under a fluorescence microscope. Fluorescent probes are well known for their high sensitivity, specificity and amenability to various spectroscopic analyses. When used in conjunction with low-light-level detectors and image processing computers, high resolution images of weak signals from single cells can be successfully acquired. In addition, the availability of digitized images has greatly facilitated the extraction of photometric and morphometric information.We use Zeiss inverted microscopes equipped with epi-illuminators and Dage-MTI ISIT video cameras or Photometrics cooled CCD cameras. Custom incubator systems built on the microscope stages allow the maintenance of live cells for up to several days. The signals are processed with image processing systems (Imaging Technologies) interfaced with graphics workstations (Silicon Graphics, Model 3130 or 4D/20) or personal computers (386/33). All images are acquired by frame averaging/signal integration, followed by subtraction of the dark noise, and storage as computer files. A variation of this simple processing strategy has allowed the detection of extremely weak signals that are essentially invisible on unprocessed ISIT images. Computer programs are then used to display sequences or images as motion pictures, to measure the linear dimension and angular orientation, and to integrate intensities over defined areas.
EM of associated spermatozoa of squirrel (Funambulus pennanti)
Authors: Bawa S. R. , Bains H. K. 
Published: June 2020

Associations amongst spermatozoa have been reported in a variety of vertebrate and invertebrate animals. Spermatozoa come together and are attached to each other only in the region of the head, their tails are free – required to steer the spermatozoa. We have studied sperm-sperm association in squirrel using electron microscopy.Small pieces of epididymides of adult squirrels (Funambulus pennanti) were fixed in cacodylate buffered glutaraldehyde and processed in a conventional manner for transmission and scanning electron microscopy Ultrathin sections and freeze-fracture replicas were examined with JEOL 1200 EX electron microscope.