bluuebunny/crossref_metadata_2025 huggingface dataset:
Visualization of the Structure of the Rat Oocyte by Scanning Electron Microscopy
Authors: Bagavandoss P.
Published: June 2020

Mammalian oocytes have been well studied with the light and the transmission electron microscopes(1,2). Glutaraldehyde and osmium tetroxide, which offer excellent fixation have certain limitations when used for SEM studies of rat ovaries. These fixatives require very small specimens for penetration, but such small specimens provide only a few intact oocytes for SEM observations. However, for meaningful observation of the changes brought about by various hormone treatments on the oocytes, a maximum number of oocytes must be available frcm a single ovary. Also, aldehyde and OSO4 fixed tissues are not easy to cut into smooth halves. This report cctnmuni- cates preparation techniques that yield useful SEM of the oocyte and associated structures of rat ovaries.

Rat ovaries were dissected out and immediately placed in Bouin's fluid for 24 hours at rocm temperature. After fixation each ovary was cut into two halves with a sharp blade and kept in 70% alcohol overnight.
Comparative Scanning Electron Microscopy Study of the Anuran Basilar Papilla
Authors: Lewis E.R.
Published: June 2020

Frishkopf and his coworkers demonstrated the auditory sensitivity and frequency range of the basilar papilla in the bullfrog; and, more recently, Capranica and his coworkers have demonstrated the auditory sensitivity and frequency range of that organ in other anuran species, spanning four of the five anuran superfamilies. In each case, the receptors of the basilar papilla respond to frequencies well above those that excite the other anuran auditory organ, the amphibian papilla. However, the range of best excitatory frequencies for the basilar papilla varies from species to species. Frishkopf and Flock have examined the bullfrog basilar papilla with TEM and light microscopy, and Lewis and Li have studied receptor surface topography in that organ with SEM; but no previous comparative studies have been reported.

To date, we have examined eleven species, spanning five families (three superfamilies) and including four of the species studied by Capranica and his coworkers.
The peroxisome membrane: effects of detergents and lipid solvents upon its ultrastructure and permeability to catalase
Authors: Yokota S. , Fahimi H.D.
Published: June 2020

The peroxisome (microbody) membrane differs markedly from other cytoplasmic membranes, especially the lysosomal, in its susceptibility to various disruptive treatments and detergents. Although this phenomenon has been extensively studied in biochemical literature, there have been no ultrastructural or cytochemical investigations of it. We now report on the effects of detergents, organic lipid solvents, and several adjuvants used in cell fractionation upon the ultrastructure of the peroxisomal membrane and its permeability to catalase, as demonstrated cytochemically by the DAB reaction and biochemically by the assay of catalase activity.
Structural modifications of intercellular junctions.
Authors: Metz J. , Merlo M. , Forssmann W. G.
Published: June 2020

Structure and function of intercellular junctions were studied under the electronmicroscope using conventional thin sectioning and freeze-etch replicas. Alterations of tight and gap junctions were analyzed 1. of exocrine pancreatic cells under cell isolation conditions and pancreatic duct ligation and 2. of hepatocytes during extrahepatic cholestasis.

During the different steps of cell isolation of exocrine pancreatic cells, gradual changes of tight and gap junctions were observed. Tight junctions, which formed belt-like structures around the apex of control acinar cells in situ, subsequently diminished, became interrupted and were concentrated into macular areas (Fig. 1). Aggregations of membrane associated particles, which looked similar to gap junctions, were intermixed within tight junctional areas (Fig. 1). These structures continously disappeared in the last stages of the isolation procedure. The intercellular junctions were finally separated without destroying the integrity of the cell membrane, which was confirmed with porcion yellow, lanthanum chloride and horse radish peroxidase.
Variations of separate junction structure in the invertebrates
Authors: Green Colin R.
Published: June 2020

Three main variations of the invertebrate septate junction are now generally accepted; the Hydra type, the pleated septate and the smooth septate junctions. A junctional study of many members of a wide range of invertebrate phyla using thin section, lanthanum tracer and freeze-fracture techniques has however revealed at least eight distinct septate junction types, including two anastomosing septate junctions in the higher invertebrate phyla.

In the Coelenterata three forms of septate junction occur. The Hydra type found in Hydrozoa (Fig 1), a pegged junction seen in the epidermal cells of Anthozoa and a ladder-like junction seen in the endodermal cells of Anthozoa. The pegged Anthozoa junction consists of septa with distinct short pegs branching at right angles mainly from one side (fig 2). Where two septa run close together, the pegs may form crossbars linking them. The ladder junction has a pegged double septum with crossbars linking the two parts of each septum (fig 3).
Detection of antibodies to rabies virus by immunoelectron microscopy
Authors: Chaudhary R. K. , Charlton K. M. , Monette M. T. , Kelen A. E.
Published: June 2020

Immunization of humans and domesticated animals at risk of contracting rabies is common practice. The mouse neutralization test (MNT) is still the standard technique used for detecting and measuring antibody to rabies virus in sera of vacinees. However, it suffers from problems of reproducibility associated with tests performed in vivo. It also has the disadvantage of being expensive, time-consuming and hazardous. Hence, there has been a continuous search for a simple, rapid and safe test. In recent years, methods based on haemagglutination, haemadsorption, plaque reduction, immunofluorescence and radioimmunoassay have been developed, but none of them has eliminated the hazard involved in the use of live virus.

With emphasis on laboratory safety, attempts were made to use inactivated rabies virus for antibody assay by immunoelectronmicroscopy (IEM), in comparison with the MNT.

Inactivated rabies virus grown in human diploid cells was supplied by Connaught Laboratories Limited (CLL). The virus was purified by sucrose density gradient centrifugation and used at a concentration to give 35-50 particles per grid square.
conformational studies of covalently closed circular viroid RNA
Authors: Klotz Günther , Kleinschmidt Albrecht K. , Sänger Heinz L.
Published: June 2020

Viroids are uncoated infectious RNA molecules pathogenic to certain higher plants. The molecular structure of viroids is characterised by single-strandedness, circularity and partial complementarity within the chain of about 350 nucleotides. In the native state the viroid molecule exists as a highly base-paired rod-like structure. Fig. 1 shows a dark-field micrograph of cucumber pale fruit viroid (CPFV) spread with cytochrome c and positively stained with uranyl salts. Under our conditions rods measure 37. 5 nm ± 2. 5 nm in length. They appear slightly flexible. Specific details are not recognized. Using benzyldimethylalkylammonium chloride (BAC) as the film forming surfactant most of the molecules appear as dumb-bell shaped rods with terminal knots (Fig. 2). Length determination led to the mean value of 33 nm ± 3 nm.

The variety of structures previously described was further investigated to assess that they reflect different conformational states of only one species of molecules.
Electron microscopy of nocardial cell division
Authors: Woodward Janet Hearn
Published: June 2020

Nocardia polychromogenes is an aerobic, gram (+), non-motile, partially acid-fast actinomycete with primary mycelia that fragment into bacillary and coccoid elements.

For scanning electron microscopy, N. polychromogenes culture strain Waksman 3409-A was grown on Potato Dextrose Agar at 25 C for 12-72 h. Five mm2 sections of the colonies, including portions of the interior and perimeter were fixed by exposure to osmium fumes for 16-24 h and air dried for 2 h. Specimens, mounted on stubs and sputter coated with gold, were viewed in a Cambridge Stereoscan Mark II scanning electron microscope. For transmission electron microscopy, the organism was grown on Potato Dextrose Agar at 25 C for 12-32 h. Whole colonies, 1-2 mm in diameter, were fixed by exposure to osmium fumes for 24 h. After suspension in noble agar, cells taken from the periphery of the fixed colonies were stained with 0. 5% uranyl acetate made in acetate-veranol buffer.
Behavior of mitochondria during sporulation in yeast
Authors: Stevens Barbara J.
Published: June 2020

The number and the form of mitochondria in vegetatively growing yeast, Saccharo-myces cerevisiae, have previously been determined by the use of serial thin sections of entire cells. It was found that the number of mitochondria is directly related to the growth phase: logarithmic phase cells contain few mitochondria, less than 10, while stationary phase cells have numerous organelles, from 30 to 50 individual mitochondria. A single mitochondrion was found in 2 log phase, glucose-repressed cells, but all other cells had more than one mitochondrion. In the present study, the behavior of the chondriome during meiosis and sporulation in yeast was followed by the serial section technique and was compared to that in vegetative cells.

Diploid strains Z193, Z239-6B6B and s4l were obtained from R. and M. Esposito and S. Klapholz (Univ. of Chicago) and serial sections of strain 112 were kindly provided by D. Zickler (Univ. Paris-Sud). Cells were fixed in glutaraldehyde, treated with glusulase (Endo Lab.) or zymolyase (Kirin Brew. Co.) to remove the cell wall, and post-fixed in Dalton's chrome osmium.
Effects of dextran on ultrastructure and function of renal tubule cells
Authors: Christensen Erik IlsØ , Maunsbach Arvid B.
Published: June 2020

Dextran, a much used plasma expander, causes pronounced ultrastructural changes in renal proximal tubule cells after intravenous injection. The aim of the present study was to determine the effects of dextran on uptake, transport, and digestion of low molecular weight protein in proximal tubule cells.

Rats of a strain tolerant to dextran were infused i. v. with dextran T 40 (10% in saline) at a rate of 7 ml/h to a total dose of 5 g/kg body weight. Control rats were infused with saline only. At the end of the infusion, the rats were injected i. v. with 0. 2 mCi of 125I-1abel1 ed egg white lysozyme. One hour later the kidneys were either fixed by perfusion with 1% glutaraldehyde and prepared for electron microscope autoradiography or slices were taken from the renal cortex and incubated in vitro to determine the lysosomal digestion of lysozyme in the proximal tubule cells.
Gap junction associated filaments in testis interstitial cells of the rat
Authors: David-Ferreira J.F. , David-Ferreira K.L. , Miranda M.H. , Lemos J.C.
Published: June 2020

The testis interstitial cells of the rat are closely associated forming small aggregates in the vicinity of the vessels. The finality of the present study is to analise the relationship between the interstitial cells and to describe some particularities of their junctions.

The observations were made in thin sections from testis of 2 to 3 months old rats fixed by immersion or perfusion with 2 to 3% glutaral- dehyde in s-collidine or cacodylate buffer followed by 2% osmium tetro-xyde in the same buffers. Some specimens have been prepared following the technique of Shea. The thin sections obtained after embedding in Epon were double stained in uranyl acetate and lead citrate. For the cryofracture study the tissues were fixed in 3% glutaraldehyde in cacodylate buffer, impregnated in 28% glycerol, frozen in Freon 22 and stored in liquid nitrogen. Freeze fracture and platinum-carbon shadowing were done in a Balzers 300.
Crystalloids of actin-like filaments in the swine sertoli cell
Authors: Toyama Yoshiro , Obinata Takashi , Holtzer Howard
Published: June 2020

Crystalloids have been observed by light microscopy in Sertoli cells of both experimentally induced and spontaneous azoospermic testes of the swine and in Sertoli cells of normal human testes. However crystalloids have not been found in normal swine testes with the light microscope. Swine crystalloids are distinguished from human crystalloids in that the diameter of the filaments is 5 nm instead of 10-15 nm. This paper confirms this distinction by showing that the filaments of swine crystalloids bind heavy meromyosin (HMM) but those of human crystalloids do not.

Human testes were removed from four patients with prostate cancer, whereas normal and cryptorchid swine testes were acquired from a slaughterhouse. HMM extracted from rabbit skeletal muscle was dissolved in 10 mM Tris buffer (pH 7. 4) containing 0. 1 M KCI and 0. 001 M MgCl2 at a final concentration of 7 mg/ml. Pieces of testicular tissue were exposed to HMM at 4°C for 24 hours after glycerination or saponin treatment.
Exocytosis by multinucleate giant cells
Authors: Papadimitriou J. M.
Published: June 2020

Multinucleate giant cells which are often found in inflammatory reactions are polykarya formed by the fusion of exuded monocytes. Such syncytia, however, display a reduced phagocytic performance in comparison to mononuclear phagocytes but cell populations containing large numbers of multinucleate giant cells have been shown to selectively secrete lysosomal hydrolases. In this communication the possibility of exocytosis by these polykarya has been investigated by ultrastructural and electron cytochemical techniques.

Multinucleate giant cells were produced by the implantation of small sheets of melenex plastic film into the subcutaneous tissues of mice. The macrophage polykarya which formed on the surface of the plastic sheet were then subjected to ultrastructural examination, either untreated or after exposure to cytochalasin B or zymosan or both. In some experiments the cells were exposed to thorotrast or ferritin before the various treatments were performed. Some specimens were stained with tannic acid while in others the electron cytochemical demonstration of acid phosphatase or surface ATPase was performed.
Inclusion body myositis: Electron microscopy study of 9 cases
Authors: Kalyan-Raman U.P. , Kalyan-Raman Krishna , Caughey R.C.
Published: June 2020

On routine examination of 266 muscle biopsies by histology, histochemistry and transmission electron microscopy, we diagnosed 9 cases of inclusion body myositis (IBM). We analyzed all the ultrastructural features present in these cases as to the pre-dictability of them in diagnosing IBM. All 9 cases shared common transmission electron microscopy features, such as: intranuclear filaments (Fig. 1), filaments within muscle fibers (Fig. 2), membranous whorls (rimmed vacuoles), cytoplasmic bodies (Fig. 3), mitochondrial accumulation and paracrystalline inclusions (Fig. A), honeycomb structures (Fig. 5), and atrophic fibers (Fig 6).

266 muscle biopsies were studied. The biopsy was obtained by using the convential muscle clamp in all the cases. After getting the muscle biopsy in each case, about 1/3 of the length was frozen in liquid nitrogen at -170 degrees F to be used for histochemistry. The second 1/3 was fixed in formalin for paraffin section, and the remaining 1/3 was minced in small pieces and fixed in 2.5% glutaraldehyde for electron microscopy study.
The application of 3D volume investigation methods to serial confocal and serial EM data: Distribution of microtubules in PC12 cells
Authors: Stevens John K. , Trogadis Judy
Published: June 2020

CAD or Computer Assisted Design uses a computer workstation to create or design new objects. Volume Investigation (VI) uses a computer workstation to understand or analyze existing objects. CAD systems are used to produce a mathematical model of a new object, stored in the workstation's memory. This model is created interactively by the user of the workstation. In contrast, VI systems synthesize a similar mathematical-model automatically from an existing object. The model is usually created or “reconstructed” from a stack of serial cross-sections of the original object. These cross-sections may be collected non-destructively from computerized tomography scans (CT), magnetic resonance imaging scans (MRI), confocal microscopy or destructively from serial light microscopy, serial electron microscopy, or any other source of serial sections. VI workstations are in widespread use in clinical settings, but have not been used at all in scientific research.
Three-dimensional microscopy and computer graphic representations of internal membrane system components of neurons
Authors: Ellisman Mark H. , Carragher Bridget , Martone MaryAnn
Published: June 2020

There are several types of intracellular membrane systems now known to be present in neurons. Much can be learned about the macromolecular composition and three dimensional distribution of many of these systems using the laser-scanning confocal microscope. However, detailed study of the morphology of these structures requires electron microscopy since most of the components of these intracellular systems are beyond the resolving power of the light microscope. Progress in selected research projects will be presented to provide examples for how new structural techniques are being used to study the internal membrane systems of neurons. Examples of membrane systems of neuronal cell bodies, and dendritic processes will be considered.
Design of an analytical TEM with integrated imaging ω spectrometer
Authors: Bihr J. , Benner G. , Krahl D. , Rilk A. , Weimer E.
Published: June 2020

Conventional transmission electron microscopy (CTEM) can be used for high resolution imaging of specimens and for the analysis of minute specimen areas. The capabilities of such an instrument are strongly improved by the integration of an imaging electron energy loss spectrometer. All imaging and diffraction techmques are provided in such an energy filtered transmission electron microscope (EFTEM).

In addition to the well-known objective lens for Koehler illumination, the new Zeiss EFTEM features a projective lens system which integrates a new imaging ω-spectrometer comprising four individual magnets and one hexapole corrector Fig.l and Fig. 3 show the design of this microscope.
Auger electron spectroscopy and microscopy in STEM
Authors: Hembree Gary G. , Luo Frank C. H. , Venables John A.
Published: June 2020

Spatial resolution in Auger electron spectroscopy (AES) is primarily a function of the excitation beam current distribution. For highest resolution the question of how to produce such a small probe of electrons is coupled with how to extract the secondary electrons efficiently from the sample. Kniit and Venables have shown the optimum configuration for highest resolution AES is a combination of a magnetic immersion lens, additional solenoids (“parallelizers“) to shape the weak magnetic field in the low energy electron transport region and a concentric hemispherical analyzer (CHA) to disperse and detect the secondary electrons. This combination has been incorporated into a new ultra-high vacuum STEM at ASU, along with the low energy electron optics required to interface the magnetic collection system with the CHA.
Improved in-lens low-loss electron detector for the Scanning Electron Microscope
Authors: Wells Oliver C. , Munro Eric
Published: June 2020

We have built an improved version of in-lens low-loss electron (LLE) detector for the scanning electron microscope (SEM) in which the LLE are energy-filtered by the focusing field. The sample is in the high-field region of a condenser-objective lens (Fig. 1). The fastest scattered electrons are then confined by the magnetic field of the lens into a region with a well-defined outer surface (Fig. 1(b)). A detector is moved under micrometer control to be just inside this surface. In this way, only the fastest scattered electrons (which are the LLE) are collected. In the earlier work, the detector was a flat aluminized garnet scintillator. This showed that the method did work but required that the incident beam energy E0 should be greater than the energy threshold of the scintillator.
High-speed electron counting system for TV scan-rate secondary-electron images of SEM
Authors: Yamada S. , Ito T. , Gouhara K. , Uchikawa Y.
Published: June 2020

We reported a system for counting secondary electrons (SEs), with which SE image quality of SEM such as signal to noise ratio (SNR) and linearity were improved, in particular under the condition of low irradiation. The system had been developed for slow-scan rates (over 6 sec/flame). The TVscan rate (1/30 sec/frame) is often used to avoid charging of insulators and biological specimens. We developed a high speed electron counting system with which SE images can be obtained in the TVscan rate. This paper describes the new system attached to an SEM, and some experimental results obtained with it.

A schematic diagram of the new system is shown in FIG.1, which consists of four main parts; Everhart-Thornley type detector (DT), main amplifier (MA), counter (CNT) and image processor (IP). In designing the system we took precautions for high speed data acquisition in the TV-scan rate. As described in the previous papers, the thermal noise and the fluctuations of the pulse height of the SE signal contained in the output of the DT can be removed through the CNT.
A computerized database for CBED bibliography using a microcomputer
Authors: Sung Changmo
Published: June 2020

Convergent beam electron diffraction (CBED) technique has been widely used to investigate characteristics of crystal structure, defects, crystal potential etc. as new materials developed. It is now a routine characterization technique especially for the identification of lattice-type, point and space group as well as defects analysis. One problem with CBED is that its use is widespread across several disciplines and therefore the results of the technique are published in a diverse range of journals and conference proceedings. Sometimes papers related to CBED are not indexed by the large bibliographic services since they deal with only titles and a few keywords of published papers. Since Lyman suggested a computerized bibliography service through EMSA/MAS only a few bibliographic databases for electron microscopy research have been published. Mannheimer compiled and published an excellent bibliography of books (written in English, French, German, Portuguese, and Spanish) on materials microscopy, a chronological listing (1940-1989).
UHV-TEM studies of laser-induced damage
Authors: Savage T.S. , Ai R. , Dunn D. , Marks L.D.
Published: June 2020

The use of lasers for surface annealing, heating and/or damage has become a routine practice in the study of materials. Lasers have been closely looked at as an annealing technique for silicon and other semiconductors. They allow for local heating from a beam which can be focused and tuned to different wavelengths for specific tasks. Pulsed dye lasers allow for short, quick bursts which can allow the sample to be rapidly heated and quenched. This short, rapid heating period may be important for cases where diffusion of impurities or dopants may not be desirable.

At Northwestern University, a Candela SLL - 250 pulsed dye laser, with a maximum power of 1 Joule/pulse over 350 - 400 nanoseconds, has been set up in conjunction with a Hitachi UHV-H9000 transmission electron microscope. The laser beam is introduced into the surface science chamber through a series of mirrors, a focusing lens and a six inch quartz window.
Electron spectroscopic imaging and diffraction
Authors: Rühle M. , Mayer J. , Spence J.C.H. , Bihr J. , Probst W. , Weimer E.
Published: June 2020

A new Zeiss TEM with an imaging Omega filter is a fully digitized, side-entry, 120 kV TEM/STEM instrument for materials science. The machine possesses an Omega magnetic imaging energy filter (see Fig. 1) placed between the third and fourth projector lens. Lanio designed the filter and a prototype was built at the Fritz-Haber-Institut in Berlin, Germany. The imaging magnetic filter allows energy-filtered images or diffraction patterns to be recorded without scanning using efficient area detection. The energy dispersion at the exit slit (Fig. 1) results in ∼ 1.5 μm/eV which allows imaging with energy windows of ≤ 10 eV. The smallest probe size of the microscope is 1.6 nm and the Koehler illumination system is used for the first time in a TEM. Serial recording of EELS spectra with a resolution < 1 eV is possible. The digital control allows X,Y,Z coordinates and tilt settings to be stored and later recalled.
X-ray photoelectron spectroscopy of annealed Co-Cr films
Authors: Demczyk B.G. , Estry H.W.
Published: June 2020

Co-Cr thin films have been studied extensively as leading candidates for perpendicular recording media. The enhancement of the magnetic properties (saturation magnetization and coercivity) in rfsputtered Co-Cr films has been reported by several investigators. Concurrent work has revealed similar improvements in the magnetic properties of annealed Co-Cr films produced by magnetron sputtering. Honda et al. propose that compositional inhomogeneities in annealed films give rise to these properties changes. In this work, we have employed X-ray photoelectron spectroscopy (XPS) to investigate compositional changes in annealed Co-Cr layers of thickness 10-200 nm.

Films were deposited from a Co-22wt%Cr alloy target onto glass (Coming Type 7059) substrates using a Varian DC Magnetron ("S" gun) sputtering system. Sputtering conditions included an argon pressure of lmTorr and room temperature substrates. The sputtering rate was 0.25 nm/sec. Annealing was performed at 360°C in a vacuum (10-6 Torr) in incremental times up to 49 hours.
A microstructural characterization of Co-Zr type permanent-magnet materials
Authors: Lawless K. R. , Hadjipanayis G. C.
Published: June 2020

Considerable interest has been shown recently in the hard magnetic properties of Co-Zr, Co-Zr-B, and Co-Hf-B alloys, but as yet no detailed microstructural studies have been published. The Co-Zr phase diagram seems to be reasonably well known, although the crystal structure of the Co11Zr2 phase is only partially determined. This paper will report on some preliminary studies of rapidly solidified Co-Zr-B-Si and Co-Hf-B-Si alloys and binary Co-Zr alloys.

All specimens used in this study were prepared by melt spinning. Specific alloys were heat treated at temperatures from 650 to 900°C. TEM specimens were prepared from ribbon material by ion milling.

X-ray diffraction studies of these alloys all showed a characteristic broad peak centered around d = 0.205nm. Although it was obvious that this was a complex peak, attempts to deconvolute it were unsuccessful. SAD patterns revealed that major phases in the alloys were very heavily faulted, thus giving rise to the very confusing X-ray diffraction patterns.
Characterization of defects and impurities in wide band gap semiconductors by cathodoluminescence in TEM
Authors: Graham R.J.
Published: June 2020

As a characterization technique for semiconductors, cathodoluminescence (CL) performed in TEM has several useful advantages over the more common SEM-based technique, the most important being that the acquisition of CL data from localized regions in an electron transparent specimen allows a correlation of microstructural and optical/electronic information. For example, it is possible to determine the distribution of low concentrations of optically active impurities and their possible association with defects, often at submicron resolution. Examples of TEM CL as a method of characterizing defects in semiconducting materials presented here are taken from wide band gap materials which are of current interest including CVD-grown diamond films and β-GaN on Si.
Microstructural characterization of implanted LOCOS + trench-isolated structures
Authors: David Theodore N. , Vasquez Barbara , Fejes Peter
Published: June 2020

As device dimensions decrease and circuit densities increase, conventional LOCOS (Local-Oxidation of Silicon) isolation presents a limitation due to lateral encroachment of the isolation-oxide. Variations in LOCOS, including poly-buffered LOCOS have been of interest as means to limit lateral encroachment of the field-oxide into the active device-region. Deep-trench isolation provides a means to support device scaling and in this work is integrated with poly-buffered LOCOS to create self-aligned shallow fieldoxide elements with minimal encroachment into active regions. Use of these technologies however requires an understanding of the behavior of the materials and structures being used and their interactions under different processing conditions. The effect of fabrication-related stresses in the structures is of interest because extended-defects, if formed, could electrically degrade devices.
Stress Relaxation and the Formation of Silicides in the Process of the Crystallization of NI-NB Films on SI
Authors: Rozhanski N. , Lifshitz V.
Published: June 2020

Thin films of amorphous Ni-Nb alloys are of interest since they can be used as diffusion barriers for integrated circuits on Si. A native SiO2 layer is an effective barrier for Ni diffusion but it deformation during the crystallization of the alloy film lead to the appearence of diffusion fluxes through it and the following formation of silicides. This study concerns the direct evidence of the action of stresses in the process of the crystallization of Ni-Nb films on Si and the structure of forming NiSi2 islands.
Tilt Unlimited: A 360 Degree Tilt Specimen Holder for the Jeol 4000-Ex 400 Kv TEM with Modified Objective Lens
Authors: Horn E. , Ashton F. , Haselgrove J. C. , Peachey L. D.
Published: June 2020

Intermediate voltage electron microscopes are used in biological research to produce high quality images of relatively thick specimens, including whole cells prepared by critical point drying and sections up to several microns thick of embedded cells and tissues. Pairs of images with the specimen tilted by angles appropriate for the magnification and the specimen thickness can be viewed stereoscopically as a way to extract 3D information from these thick specimens. The tilts appropriate for stereo imaging of such thick specimens usually don't exceed +/-20 degrees. Quantitative 3D measurement and 3D reconstruction using tomography or computer graphic tracing methods give the highest accuracy results when the maximum range of tilt angles is available.
Core excitation studies of poly(ethylene terephthalate) and molecular analogues by EELS
Authors: Rightor E. G. , Hitchcock A. P. , Urquhart S. G. , Wen A. T.
Published: June 2020

The near-edge region of core ionization edges can be used as a probe of the local bonding and structure of atoms excited by incident radiation, such as in electron energy loss spectroscopy (EELS) or x-ray absorption techniques. Recent installation of efficient parallel EELS spectrometers in ATEMs promotes study of these transitions in radiation sensitive materials such as polymers. To study relationships between poly(ethylene terephthalate) [PET] structure and EELS transitions, we compared polymer spectra with molecular analogues.

The PET examined (from Scientific Polymer Products) was cut using a diamond knife and a Reichert-Jung Ultracut E ultramicrotome with FC4E cryoattachment. A JEOL 2000FX TEM with a LaB6 filament and a Gatan parallel-EELS system was used to examine PET sections on holey carbon. The gas phase EELS of molecules (from Aldrich, Matheson) was performed under inelastic scattering conditions as described previously.
The Use of Microspectroscopy in the Stem for the Identification of Membrane Components
Authors: Hainfeld J. , Isaacson M. , Sogard M.
Published: June 2020

In recent years, more notice has been given to the fact that the energy loss spectra of fast electrons transmitted through thin specimens may be employed to analyze their composition (e.g. refs. 1,2). A program to explore the usefulness of energy loss spectra (with a STEM) in identifying the components of biological membranes has been initiated.

One would like to scan, for example, over an intact membrane surface and analyze, point by point, the composition. However, some preliminary studies are necessary: First, the energy loss spectra of each major membrane component must be determined; second, the change in these spectra with beam dose must be found, since damage may be a problem as resolution (and therefore dose) is increased; third, a practical scheme of obtaining point-bypoint data (i.e., pictures that relate composition to contrast) must be devised.
Neuromuscular Junction Variability on Multiply Innervated Fibers of Rabbit Extraocular Muscle
Authors: Davidowitz Jacob , Pachter Bruce R. , Breinin Goodwin M.
Published: June 2020

It is well known that mammalian extraocular muscle (EOM) contains multiply innervated fibers (MIF) in addition to those with single innervation (SIF). There is general agreement that nerve endings on the SIF are not significantly different from end plates of the peripheral musculature. While the neuromuscular junctions on MIF are usually described as being small and superficial, light microscopy of rabbit (1) and rat (2) EOM indicates that both large and small endings may occur on MIF. An EM study of rat EOM (2) suggests that the large endings on MIF are essentially a tight grouping of superficial endings with minimal junctional folding. In the present study of rabbit EOM, end-plate-like endings were observed on MIF in addition to numerous more or less superficial neuromuscular junctions. The m. superior rectus of New Zealand white rabbit was prepared by standard methods, and embedded whole in Epon 812.
Ultrastructure of the Celis of a Fish Tastebud
Authors: Korte Gary E.
Published: June 2020

Four types of specialized epithelial cells have been observed in the fish tastebud, within the capsule formed by the flattened epidermal cells. However, only two or three of these have been previously noted in any one species, including the glass catfish Kryptopterus bicirrhis, the subject of this investigation (1,2). For the first time, all four types of specialized cells have been observed,and an artifact of fixation relevant to the identification of these cell types has been uncovered.

A single basal, or B cell lies on the basement membrane of the epidermis (Fig. 1). It makes many synapses with the afferent nerve plexus, which lies just above it. The other three cell types, designated S,L and T cells (Fig. 2A) are external to the nerve plexus, and only rarely make synapses onto nerves, confirming the observations of several other investigations.
Ultrastructural Description of three Different Epithelial Cell Types in Rat Mammary Gland.
Authors: Russo I.H. , Ireland M. , Isenberg W. , Russo J.
Published: June 2020

The mammary gland is composed of epithelial and myoepithelial cells. In the present work, we show that the epithelial component is composed of three types of cells differing in their ultrastructural profiles.

Sprague-Dawley virgin female rats, 60 to 100 days old, were sacrificed during estrus. The mammary gland was fixed in Karnovsky's fluid (1), embedded in Epon-Araldite (2), thin-sectioned, stained with uranyl acetate and lead citrate, and examined in an Hitachi HU-11A or a Siemens Elmiskop 1A. To see whether ultrastructural differences correspond to size differences, the nuclear and cytoplasmic areas of 1000 cells were determined from photographs at 10,000X, using a compensating polar planimeter.

The population of epithelial cells in the mammary gland is comprised of three different cell types (Fig. 1): a) light cells, b) dark cells, and c) intermediate cells.
Comparative Scanning Electron Microscopy of the Outer Wall of the Bladder of C. Cellulosae and C. Racemosus.
Authors: González-Angulo A. , Hernández-Jáuregui P. , Rabiela M. T. , Ruíz de Chávez. I.
Published: June 2020

Whereas clear cut differences are grossly apparent between Cysticercus cellulosae and Cysticercus racemosus (1), their origin from one or two separate species of taeniae is still unsolved. An attempt was made to find ultrastructural differences or similarities on the external configuration of the bladder of these two cestode larvae which may shed light on their origin. For this, a scanning electron microscopy study was carried out in C. cellulosae and C. racemosus obtained from human brains and of C. cellulosae obtained from skeletal muscle of infested swine. Tissue from the wall of the bladder was fixed dehydrated and further desiccated by the critical point drying method. After gold coating, the samples were examined in a JSM-35 scanning electron microscopy when seen in lower magnifications.
Negative Staining of F-Actin and Actin-Like Microfilaments using Tannic Acid
Authors: LaFountain J.R. , Zobel C.R. , Thomas H.R. , Galbreath C.
Published: June 2020

Subsequent to its introduction a few years ago by Mizuhira and Fukaesaku (1) the practice of using tannic acid (TA) in glutaraldehyde (GA) fixatives followed by heavy metal postfixation has become a standard technique for revealing the substructure of microtubules. We showed in a previous report that a reaction similar to that between TA and tubulin also occurs between TA and actin. Actin filaments of striated muscle appear negatively stainedin situafter GA-TA fixation and osmium postfixation (2). That result suggested that GA-TA fixatives might be applied to studies of actin-like filaments in non-muscle cells. However, in light of the results of Szamieret at(3) showing that naked (not protected by tropomyosin) F-actin is destroyed by osmium, it was questionable whether it was possible to preserve and negatively stain naked F-actin, as well as actin-like microfilaments, with GA-TA fixatives. Also, we did not know if osmium must be used as a postfixative or whether other heavy metals could be substituted for it.
Preparation of Freeze-Stopped Rat Liver Tissue for Transmission Electron Microscopy
Authors: Lim B. S. , Veech R. , Slovis R. , Solomon J. D.
Published: June 2020

The relationship of morphological integrity and viability of mitochondria in freeze-stopped cells is of considerable interest and importance to biological scientists. This study represents the preliminary work for obtaining ultrastructural data for comparison with glutamate dehydrogenase activity, a marker for mitochondria protein, on freeze-stopped liver tissue from the rat.

The pellets of ground freeze-stopped rat liver were fixed in three different ways: (l) OsO4 fume fixation. The fixing chamber consists of a capped plastic centrifuge tube containing an open ampule of OsO4 crystals. The chamber was maintained at -90°C at all time before and during fixation. After an overnight fixing, the tissue pellets were gradually brought to 4°C in a refrigerator and postfixed in glutaraldehyde.
Rapid Infiltration of Biological Tissues Utilizing n-Hexenyl Succinic Anhydride (HXSA)/Vinyl Cyclohexene Dioxide (VCD), An Ultra-Low Viscosity Embedding Medium.
Authors: Mascorro Joe A. , Ladd Margaret W. , Yates Robert D.
Published: June 2020

HXSA/VCD recently was introduced as an ultra-low viscosity embedding medium for biological electron microscopy (Mascorro et al., TSEM/LSEM Joint Symposium Proceedings, In Press, 1976). The medium utilizes a newly developed short carbon chain anhydride (HXSA) in combination with components of known low viscosities. The completed medium exhibits a markedly low viscosity (20 ±1 cps d 25°C) which facilitates rapid and complete infiltration in minimum time. The components and preparation of the medium are as follows:

A small amount of standard mix includes 5 grams VCD, 10 grams HXSA, 0.75 gram Araldite RD-2 and 0.15 gram DMAE, combined gravimetrically. Components are drawn by syringe and dispensed into a dry beaker placed on a Mettler balance. The fluid nature of the medium allows precise measuring.
Microchemical Analysis of thin Metal Foils
Authors: Zaluzec N. J. , Fraser H. L.
Published: June 2020

Several techniques have been developed for quantitative x-ray microanalysis of thin metal foils. These techniques usually provide relative elemental concentrations, and assume that for a “thin” homogeneous alloy of elements A and B, the ratio of intensity (I) of any two characteristic x-ray peaks (e.g.IAKα/IBKα) should be independent of specimen thickness. Recently, Fraser et al., conducted experiments using a highly ordered alloy (β-NiAl) to investigate this assumption, and indeed showed that in electron transparent regions of the foils there was a marked variation in the ratio of the Ka peaks of Ni and Al, respectively. The results given by Fraser et al., are summarized in Fig. 1.
A Bending Holder for “In-Situ” Deformation Of Electron Microscope Specimens
Authors: Noggle T. S. , Narayan J.
Published: June 2020

The use of “in-situ” deformation for the study of deformation in the electron microscope has been inhibited either by the special specimen and specimen mounting requirements of deformation stages and/or the limitations on specimen tilting for control of diffraction contrast and analysis of the deformation structures. We report here on a deformation holder which was designed for use in a Hitachi 200E electron microscope, but whose basic features should adapt to holders for use in other makes of electron microscopes. This holder permits tilting of the specimen over the full range (10°) of the tilting specimen stage, employs standard 3-25 mm. diameter specimens which have been dimpled on one side and thinned for electron transmission and permits controlled introduction of strain into the specimen.
Considerations in Making Stereo Micrographs with the Scanning Electron Microscope - Positioning the Stereo Window
Authors: Walter Earl R.
Published: June 2020

A variety of factors must be controlled in order to obtain stereo micrograph pairs with the SEM which provide maximum effectiveness along with ease of viewing. These include the following:

1. Where possible, micrographs should be sharp from edge to edge. This may require the use of an Autofocus attachment although somewhat the same effect can be obtained by maintaining the point of sharpest focus near opposite edges of the two micrographs forming the stereo pair.

2. The difference in tilt angle between the two micrographs of the pair should be kept in the4to 6° range to provide a normal perspective.

3. Micrographs forming a stereo pair should be made at relatively low tilt angles to prevent large differences in the field of view of the two micrographs and to minimize the left to right magnification variations.
On the Shape of Field-Ion Emitters
Authors: Eaton H.C. , Ranganathan B.N. , Burwinkle T.W. , Bayuzick R. J. , Hren J.J.
Published: June 2020

The shape of the emitter is of cardinal importance to field-ion microscopy. First, the field evaporation process itself is closely related to the initial tip shape. Secondly, the imaging stress, which is near the theoretical strength of the material and intrinsic to the imaging process, cannot be characterized without knowledge of the emitter shape. Finally, the problem of obtaining quantitative geometric information from the micrograph cannot be solved without knowing the shape. Previously published grain-boundary topographies were obtained employing an assumption of a spherical shape (1). The present investigation shows that the true shape deviates as much as 100 Å from sphericity and boundary reconstructions contain considerable error as a result.

Our present procedures for obtaining tip shape may be summarized as follows. An empirical projection, D=f(θ), is obtained by digitizing the positions of poles on a field-ion micrograph.
Field Emission Analytical Electron Microscope
Authors: Harada Y. , Kokubo Y. , Goto T. , Tamura N. , Iwatsuki M. , Koike H.
Published: June 2020

Recently, analytical electron microscopes (AEM), which provide the functions of the transmission electron microscope (TEM), scanning electron microscope (SEM) and energy dispersive X-ray spectrometer (EDS) have been put to practical use with a view to analyzing elements in micro areas, xo improve the performance of this type of AEM, a field emission gun was attached to our AEM instead of a conventional thermionic gun. This has allowed a sellected area smaller than several 100 Å to be easily analyzed. Moreover, an electron energy analyzer (EA) was attached to the AEM for detecting light elements which cannot be detected by the EDS.These modifications have resulted in an advanced type of an AEM, namely, a field emission analytical electron microscope (FEAEM).

Fig. 1 shows a general view of our FEAEM. The feature of this FEAEM is that it is designed on the basis of a 100 kV field emission electron microscope provided with a strongly-excited objective lens having a very small aberration coefficient and with an eucentric goniometer tiltable to 60°.
Autocatalytic Nucleation of Omega Phase in a Beta-Titanium Alloy
Authors: Headley T. J.
Published: June 2020

The well-known ββ+ω transformation has been observed in many b.c.c.- stabilized titanium, zirconium, and hafnium alloys(1,2). Although considerable controversy still exists regarding the exact mechanism(s) for formation of the ω phase, recent studies suggest that both the athermal and isothermal types form by the same mechanism and that they may therefore be considered equivalent products(3,4).

The present observations are concerned with the formation of isothermal w in the B-titanium alloy RMI(38-6-44) [composition in wt.%: 3.4 Al, 8.3 V, 5.8 Cr, 3.9 Zr, 4.2 Mo, balance Ti] and form a part of a more general study of the aging characteristics of this alloy(5). The alloy was solution treated at 927°C, air-quenched, aged at appropriate temperatures, and examined in a Phillips EM 200 electron microscope. TEM failed to reveal the presence of athermal m in the solution treated and quenched material. Isothermal OJ formed during aging at 250° and 300°C, but it was not stable at temperatures of 350°C and above.
Nature and Distribution of Pyrite in Iowa Coal
Authors: Greer Raymond T.
Published: June 2020

Iowa has a large reserve of high-sulfur coal. In view of the projected energy requirements for the state, in-state coal resources should provide a significant contribution. Environmental considerations and air pollution regulations emphasize the desirability of sulfur removal. Both microstructural and microchemical characteristics of Iowa coal relate to the choice and improvement of processing and purification procedures, as well as provide information which may aid in local correlation of deposits.

Iron sulfides occur in the coal as nodules and narrow seams (up to 150 mm thick, thinning out over a distance of hundreds of millimeters) and in finely disseminated form. Individual pyrite euhedra occur predominantly in a size range of about one to 40 micrometers in diameter, with by far most of the crystallites being one to two micrometers in diameter (Fig. 1). This raises special characterization problems for routine conventional optical microscope studies. The pyrite also occurs as spherical assemblies of crystallites. These framboidal masses (after Framboise, the French for Raspberry) range from a few micrometers to several hundred micrometers in diameter, with most of them being approximately 10 and 20 micrometers in diameter (Fig. 2).
Lorentz Microscopy on Amorphous Films with Perpendicular Anisotropy as a Function of Temperature
Authors: Herd S. R.
Published: June 2020

Lorentz microscopy on amorphous thin films of GdCoX (X=Au,Mo) with perpendicular anisotropy is used to show the change in the magnetic domain structure as a function of Q, the ratio of perpendicular anisotropy, Ku, to the square of the saturation magnetization . The films were prepared by RF-sputtering on to HaCl substrates from which they were floated off on to standard electron microscope grids. After a slight modification of the Philips EM-301 objective lens the current could be varied smoothly down to 0 which allowed use of the objective lens field as perpendicular bias field while the diffraction lens was used to obtain the out-of-focus image.

As the perpendicular anisotropy increases, striped domains are formed in which the magnetization oscillates between ± TT/4 in and out of the plane of the film in the direction of the in-plane field component.