bluuebunny/crossref_metadata_2025 huggingface dataset:
TEM in situ annealing of fluorine-implanted amorphized silicon
Authors: Kaushik Vidya S. , Hance Robert L. , Grove Charlotte L.
Published: June 2020

In situ heating experiments in the transmission electron microscope offer unique opportunities to visualize and understand material behavior. The annealing behavior of silicon amorphized by conventional dopant implants as studied by in situ TEM has been reported in the literature. As part of a study on the behavior of fluorine in silicon, we have performed in situ anneals of fluorine-implanted amorphized silicon on XTEM samples, and compared these with bulk furnace-annealed samples.

The wafer was an n-type (100) silicon (18-24 ohm-cm) implanted with 1 x 1016 /cm2 fluorine at 60 keV at room temperature through a 13 nm oxide layer. The XTEM samples were heated within the TEM in a Gatan sample holder in a JEOL 2000 FXII STEM operated at 200 kV. The behavior of the sample was observed using a wide angle CCD TV camera and recorded on videotape. Micrographs were recorded before the anneal and after the temperature had stabilized.
Deposition and anneal behavior of Al-1.5%Cu films: TEM characterization
Authors: David Theodore N. , Dreyer Mike , Varker Charles
Published: June 2020

Al-1.5%Cu materials are of interest for interconnect-metallization in semiconductor integrated-circuits. It is known from the literature that the mean-time-to-failure (MTF) due to electromigration of the Al-1.5%Cu interconnects depends on the microstructure of the materials. A correlation is seen for instance between grain-size distributions in the material and the MTF. Uniform large-grained distributions improve lifetime. The present study evaluated the microstructure of Al-1.5%Cu films deposited and annealed under different conditions.

Al-1.5%Cu films had been deposited at 25°C and at 300°C; the layers had then been annealed at 300°C for 17 hours, prior to TEM investigation. Plan-view TEM specimens were prepared in the 100 substrategeometry, and cross-section TEM specimens were prepared in the 110 substrate-geometry. These were then analyzed using bright-field and dark-field TEM imaging techniques. A JEOL JEM 200CX transmission electron microscope was used for the investigation, operating at 200 kV.
Structure and Orientation of As Precipitates in LT-MBE Grown GaAs
Authors: Claverie Alain , Liliental-Weber Zuzanna
Published: June 2020

GaAs layers grown by MBE at low temperatures (in the 200°C range, LT-GaAs) have been reported to have very interesting electronic and transport properties. Previous studies have shown that, before annealing, the crystalline quality of the layers is related to the growth temperature. Lowering the temperature or increasing the layer thickness generally results in some columnar polycrystalline growth. For the best “temperature-thickness” combinations, the layers may be very As rich (up to 1.25%) resulting in an up to 0.15% increase of the lattice parameter, consistent with the excess As. Only after annealing are the technologically important semi-insulating properties of these layers observed. When annealed in As atmosphere at about 600°C a decrease of the lattice parameter to the substrate value is observed. TEM studies show formation of precipitates which are supposed to be As related since the average As concentration remains almost unchanged upon annealing.
Solid-State Amorphization in a Ti/B Multilayer
Authors: Jankowski Alan F. , Wall Mark A. , Makowiecki Daniel M.
Published: June 2020

Thin films of pure crystalline metals, that have a negative heat of mixing, are known to amorphize. Solid-state amorphization reactions are possible to study using multilayered structures. The amorphization reaction is typically observed in multilayered structures in which one layer of the pair is crystalline and the adjacent layer or interface is amorphous, as in Ni/Zr and Cu/Y. The reaction progresses via a low temperature isothermal anneal (at several hundred degrees centigrade) in which one species preferentially diffuses into the other. Recently, in-situ observation of solid-state amorphization in a completely crystalline Ni/Ti multilayer indicates that nucleation of the amorphous phase occurs at incoherent crystalline interlayer boundaries. (The completely crystalline as-deposited structure was achieved by ensuring thermalization of the sputtered neutrals.) The progression of solidstate amorphization in Ti-B is examined using the multilayered configuration.
On the Phase Transformation between the Quasicrystalline to Crystalline Phases in Alloys of Al-Cu-Fe-Co
Authors: Pérez R. , Juárez-Islas J.A. , Martínez L. , Campillo B. , Albarrán J.L.
Published: June 2020

We report in this investigation preliminary results on the phase transformations between the quasicrystalline phases in quaternary alloys of Al-Cu-Fe-Co to crystalline structures. In these alloys obtained by normal casting methods under inert atmospheres both quasicrystalline phases; icosahedral and decagonal are found to coexist. By means of annealing, transformation of the quasicrystalline phases to crystalline structures are induced.

Although not quite clear from diffraction patterns along the five-fold and threefold axis, experimental evidence on this crystallization process is clearly obtained along the two-fold axis. The diffraction patterns obtained from the annealed specimens show sign of different degrees of crystallization for different quasicrystalline grains.
TEM Studies of Grain Boundary Films in Si3N4 Ceramics
Authors: Kleebe H.-J. , Vetrano J.S. , Bruley J. , Rühle M.
Published: June 2020

It is expected that silicon nitride based ceramics will be used as high-temperature structural components. Though much progress has been made in both processing techniques and microstructural control, the mechanical properties required have not yet been achieved. It is thought that the high-temperature mechanical properties of Si3N4 are limited largely by the secondary glassy phases present at triple points. These are due to various oxide additives used to promote liquid-phase sintering. Therefore, many attempts have been performed to crystallize these second phase glassy pockets in order to improve high temperature properties. In addition to the glassy or crystallized second phases at triple points a thin amorphous film exists at two-grain junctions. This thin film is found even in silicon nitride formed by hot isostatic pressing (HIPing) without additives. It has been proposed by Clarke that an amorphous film can exist at two-grain junctions with an equilibrium thickness.
Preliminary Study of Domain Boundaries in Barium Titanate with High Angle Annular Dark Field(HAADF) Imaging
Authors: Tsai Feng , Wang Shi-Yao , Cowley John M.
Published: June 2020

BaTiO3 have been studied for years by electron microscopists. Those studies have revealed the existence of 90° and 180° ferroelectric domain boundaries. The high angle annular dark field(HAADF) STEM technique is known to have strong sensitivity to atomic number Z. The signal is generated by the channelling of electrons along rows or planes and high angle scattering(mostly thermal diffuse scattering) from the atoms. Contrast in HAADF images can be given by crystal defects as a result of changes in channeling or changes in the high angle scattering process. This work reports a preliminary study of ferroelectric domain boundaries in BaTiO3 with HAADF imaging and a qualitative discussion of the observed domain wall contrast.
A Novel TEM Technique for Characterizing As-Grown CVD Diamond Films
Authors: Wang Z.L. , Bentley J. , Clausing R.E. , Heatherly L. , Horton L.L.
Published: June 2020

Microstructural studies by transmission electron microscopy (TEM) of diamond films grown by chemical vapor deposition (CVD) usually involve tedious specimen preparation. This process has been avoided with a technique that is described in this paper. For the first time, thick as-grown diamond films have been examined directly in a conventional TEM without thinning. With this technique, the important microstructures near the growth surface have been characterized. An as-grown diamond film was fractured on a plane containing the growth direction. It took about 5 min to prepare a sample. For TEM examination, the film was tilted about 30-45° (see Fig. 1). Microstructures of the diamond grains on the top edge of the growth face can be characterized directly by transmitted electron bright-field (BF) and dark-field (DF) images and diffraction patterns.
Transmission Electron Microscopy of Shock-Deformed Sapphire
Authors: Chen S.-J.
Published: June 2020

An understanding of the micromechanisms which occur during the shock deformation of hard ceramic materials would be helpful to the development and optimization of these materials in ballistic environments. Previous studies of shock loaded alumina show evidence of plastic flow by basal slip 1/3<110> (0001), basal twinning, pyramidal slip 1/3<010>{113} and prismatic slip 1/3<101>(110), It has also been observed that the grain boundary and interphase material (e. g. glass) play an important role in determining the microstructural characteristics. In order to elucidate the response of different slip systems, as a function of the impact orientation and the magnitude of peak pressure, some experiments with single crystal alumina (sapphire) have been carried out and the preliminary results are presented here.
AEM of Bi-Processed Mg2Al4Si5O18: Cation Chemistry of Hexagonal and Orthorhombic Cordierites
Authors: Schwartz K.B. , Leong D.B. , McConville R.L.
Published: June 2020

Cordierite, Mg2Al4Si5O18, is a refractory aluminosilicate whose low dielectric constant, good strength, and small thermal expansion coefficient are valued in applications of ceramic technology. A significant impediment to its widespread use in ceramic packaging of electronic circuits has been difficulties inherent in standard fabrication techniques. Recently, a new process has been developed for the preparation of cordierite below 1000°C using a bismuth oxide flux. This process produces dense cordierite bodies containing residual amounts of bismuth oxide flux at grain boundaries and triple points.
Tensile Creep of Y-Si3N4: II. Cavitation
Authors: Hockey B. J. , Wiederhorn S. M.
Published: June 2020

ATEM has been used to characterize three different silicon nitride materials after tensile creep in air at 1200 to 1400° C. In Part I, the microstructures and microstructural changes that occur during testing were described, and consistent with that description the designations and sintering aids for these materials were: W/YAS, a SiC whisker reinforced Si3N4 processed with yttria (6w/o) and alumina (1.5w/o); YAS, Si3N4 processed with yttria (6 w/o) and alumina (1.5w/o); and YS, Si3N4 processed with yttria (4.0 w/o). This paper, Part II, addresses the interfacial cavitation processes that occur in these materials and which are ultimately responsible for creep rupture.
Image-Recording Systems for Photons and Charged Particles
Authors: Timothy J. Gethyn
Published: June 2020

Image-recording systems for photons and charged particles are under intensive development at this time to meet the needs of space astrophysics and space plasma physics missions. Many of these image-recording systems are also finding applications in a number of other disciplines.

A number of different technologies for photon imaging have made major progress in the past five years. First, the development of T-grain emulsions has significantly improved the resolution and dynamic range of photographic emulsions and greatly improved their sensitivity at extreme-ultraviolet and soft x-ray wavelengths.
Multiple-inelastic phonon, single electron, and valence excitations in high-energy electron scattering
Authors: Wang Z. L.
Published: June 2020

In this paper, inelastic scattering theory, as described in Reference 1, is applied to multiple-elastic and -inelastic electron scattering in crystals. Under the small angle approximation, the inelastically scattered wave Ψnof energy En=E-enafter exciting the nthcrystal excited state can be taken as a position modification to the elastically scattered wave,

(1)

where Ψn0(r) is the elastic wave of wave vector knand satisfies the elastic scattering Schrödinger equation,

(2)

and V = H'nnis the crystal potential;. Under the small angle and forward scattering approximations

(3)
Surface morphology characterization of industrial polymers by low-voltage scanning electron microscopy
Authors: Berry V. K.
Published: June 2020

There has been an increase in awareness in low voltage scanning electron microscopy (LVSEM) of polymers in recent years because not only is it possible to use uncoated or very lightly coated (1-5nm) polymer samples but also due to an inherent advantage of limited beam damage of polymer samples by low energy beams. A steady increase in the use of low accelerating voltages for characterizing polymers has been made possible due to some major developments, such as high brightness field emission source, better lens and column design to minimize lens aberrations, and newer and improved detector systems with higher collection efficiency, incorporated by instrument manufacturers in their newer commercial models in recent years. Although there is still room for further improvements, the described instrumental changes have made possible the appreciation of LVSEM in characterization of polymers and non-conducting, beam sensitive materials.
Phase transitions of a comb-shaped side-chain polyester: An electron diffraction study
Authors: Li L. S. , Stupp S. I.
Published: June 2020

In order to reveal the phase transition sequence of aromatic polyesters and to characterize each phase appearing during heating, a comb-shaped side-chain polyester has been studied using electron diffraction techniques at room and higher temperatures. The chemical structure of the polyester is shown below,

Fig. 1 is an electron diffraction pattern of two layers of the polymer, showing a chiral smectic E phase at room temperature. In this phase each layer consists of three orthorhombic lattices with orientations related to each other by rotations of ±60° as in a smectic E phase. However, there is an additional rotation of 5.9° between orthorhombic lattices in adjacent layers. When this polymer was heated to 67°C the electron diffraction pattern changed dramatically (Fig. 2). There are six strong reflections arrayed at equal angles, and the whole pattern shows a hexagonal reciprocal lattice plane. This indicates that the structure of the polymer is no longer that of a chiral smectic E phase, but a new phase, which is similar to the phase of p-hydroxybenzoate/m-hydroxybenzoate copolymer(95/5) at 350°C.
Electron microscopy of crystalline structure in thermotropic random copolymers
Authors: Anwer Afzana , Eilidh Bedford S. , Spontak Richard J. , Windle Alan H.
Published: June 2020

Random copolyesters composed of wholly aromatic monomers such as p-oxybenzoate (B) and 2,6-oxynaphthoate (N) are known to exhibit liquid crystalline characteristics at elevated temperatures and over a broad composition range. Previous studies employing techniques such as X-ray diffractometry (XRD) and differential scanning calorimetry (DSC) have conclusively proven that these thermotropic copolymers can possess a significant crystalline fraction, depending on molecular characteristics and processing history, despite the fact that the copolymer chains possess random intramolecular sequencing. Consequently, the nature of the crystalline structure that develops when these materials are processed in their mesophases and subsequently annealed has recently received considerable attention. A model that has been consistent with all experimental observations involves the Non-Periodic Layer (NPL) crystallite, which occurs when identical monomer sequences enter into register between adjacent chains. The objective of this work is to employ electron microscopy to identify and characterize these crystallites.
Cryomicroscopy of multiphase latices
Authors: Shaffer O. L. , El-Aasser M.S. , Zhao C. L. , Winnik M. A. , Shivers R. R.
Published: June 2020

Transmission electron microscopy is an important approach to the characterization of the morphology of multiphase latices. Various sample preparation techniques have been applied to multiphase latices such as OsO4, RuO4 and CsOH stains to distinguish the polymer phases or domains. Radiation damage by an electron beam of latices imbedded in ice has also been used as a technique to study particle morphology. Further studies have been developed in the use of freeze-fracture and the effect of differential radiation damage at liquid nitrogen temperatures of the latex particles embedded in ice and not embedded.

Two different series of two-stage latices were prepared with (1) a poly(methyl methacrylate) (PMMA) seed and poly(styrene) (PS) second stage; (2) a PS seed and PMMA second stage. Both series have varying amounts of second-stage monomer which was added to the seed latex semicontinuously. A drop of diluted latex was placed on a 200-mesh Formvar-carbon coated copper grid.
Imaging CPE/PVC phase morphology using a transmission detector in the SEM
Authors: Barnes C. G. , Rightor E. G.
Published: June 2020

Characterization of the phase morphology of chlorinated polyethylene (CPE) modified poly (vinyl chloride) (PVC) blends is crucial in understanding the physical properties. Scanning transmission electron microscopy (STEM) can successfully reveal the phase morphology in unstained specimens of these materials, resulting in a significant decrease in analysis time -and elimination of staining techniques required for convention TEM. The advantages of STEM for such materials arise from the smaller electron dose, minimal irradiation of adjacent specimen regions, and electronic signal enhancement capabilities.

We have combined these advantages and the availability of an SEM by utilizing a transmission detector to perform SEM based STEM. Development of this technique has focussed on image quality, contrast, resolution, and minimization of specimen irradiation damage. The experiments were performed in a Cambridge S200 SEM @30 KeV using a commercial solid state transmission detector (K. E. Developments Ltd.), which is mounted beneath the electron transparent specimen.
TEM observations of electromagnetically characterized YBa2Cu3O7-x grain boundaries in flux-grown bicrystals
Authors: Babcock S.E. , Zhang N.
Published: June 2020

The original thin-film bicrystal studies strongly indicated that all high-angle grain boundaries in YBa2Cu3O7-x are intrinsically weak-linked and exhibit Josephson junction characteristics. More recent investigations of individual grain boundaries in both bulk-scale bicrystals and textured thin films have shown that the Jct properties of high-angle grain boundaries can vary in important ways. Specifically, high-angle grain boundaries with Jct behavior characteristic of a flux pinning mechanism have been discovered. These results are encouraging from the view point of large-scale applications. However, further engineering of polycrystalline materials can first be conducted in a deliberate way when the microstructural origin of the observed behaviors is understood in detail.

In these studies, light and transmission electron microscopy techniques are used to investigate the microstructure of the very same bulk bicrystalline samples whose electromagnetic properties have been characterized. The three-dimensional macroscopic features of the grain boundary are deduced from light microscopy observations as the entire bicrystal is mechanically ground and polished to approximately 20 microns in thickness.
Observations of strong pinning centers in Y-Ba-Cu-O
Authors: Zhang J. P. , Li D. J. , Marks L. D. , Lin C. H. , Eades J. A.
Published: June 2020

Using additional Y (or Cu) nitrate we had been successful in production of Y-enriched 123 (YBa2Cu3O7-x) as well as Cu-enriched ones. The magnetic Jc at 77K is 106 (B=0) and 105 (B=1 Tesla). A critical issue is the understanding flux pinning in terms of defects in microstructure.

Precipitates were observed inside of the 123 crystal as shown in Fig. 1. These precipitated slabs are usually 3 - 10 nm long along c axis of 123 and 101 - 102 nm in the a-b plane, similar to that reported in CVD films. An interesting point is the precipitates found in both Yenriched and Cu-enriched samples have similar size and morphology. It is reasonable to assume those precipitates are the strong pinning centers for the size effect as known in type II superconductors. In the 123 compound the coherent length is about 2∼3 angstrom in the c direction and 16∼30 angstrom in the a-b plane.
Fine Structural Effects of Vasectomy Upon the Male Reproductive System
Authors: Heidger Paul M. , Sawatzke Cheryl L.
Published: June 2020

In view of the 1 million vasectomies performed each year in the United States alone, it is mandatory that a thorough understanding be gained of possible cytological and immunological effects of the procedure. Studies have been conducted in our laboratory on rats, dogs, and monkeys, utilizing a variety of techniques of vasectomy, followed by TEM examination of tissues at various times post-operatively. of particular interest has been the response of the seminiferous epithelium, the vas deferens, and the epididymis to the procedure. Alterations within either the seminiferous epithelium or the excurrent duct system of the testis are of significance in light of recently renewed interest in exploring vasectomy as a reversible means of birth control, in the face of commonly reported low success rates in reestablishing fertility in men following relatively long-term vasectomy.
Ultrastructure of Melanin Formation in Thielaviopsis Basicola
Authors: Wheeler M. H. , Tolmsoff W. J. , Bell A. A. , Stipanovic R. D.
Published: June 2020

Melanin formation in the fungus Thielaviopsis basicola was examined by light and electron-transmission microscopy with methods described previously in studies of Verticillium dahliae (1,2). A wild-type isolate and an albino mutant of T. basicola were grown on potato-carrot-dextrose-agar medium at 24°C prior to chemical treatment. The wild-type isolate was examined and compared with the albino mutant before and after treatment with each of the following compounds that have been proposed as melanin intermediates in various fungi (3): (+)-scytalone [3,4-dihydro-3,6,8-trihydroxy-l-(2H)- naphthalenone]; 1,8-dihydroxynaphthalene (DHN); L-3,4-dihydroxyphenylalanine (DOPA); and catechol.
Intranuclear Inclusions of Mitochondria in Myopathic Extraocular Muscle
Authors: Davidowitz Jacob , Pachter Bruce R. , Breinin Goodwin M.
Published: June 2020

Nuclei often display aberrant inclusions which may be variously unbounded or enclosed within single or double membranes. True intranuclear inclusions are distinguishable from pseudoinclusions which represent planes of section through invaginations of the nuclear envelope, insofar as the latter are characteristically bounded by the outer and inner membranes of the indented perinuclear cisterna. It has been suggested that unbounded apparently true nuclear inclusions might in some cases be derived from pseudoinclusions, the enclosing membranes of which had undergone dissolution subsequent to an engulfment process.2,3 This suggestion was posited in the contexts of intranuclear (a) glycogen accumulations, which might also develop by means of in situ mechanisms and (b) membranous structures, which might also develop from proliferations of the inner nuclear membrane.
High Voltage Electron Microscopy of Cultured Muscle Cells
Authors: Shay Jerry W.
Published: June 2020

It is known from earlier observations that the in vitro rat L6 muscle cell line exhibits many of the features characteristic of in vivo muscle differentiation. The appearance of multinucleated cells, the development of highly organized contractile proteins and the phenomenon of muscle contraction are all easily recognizable features unique to muscular tissue. The L6 myoblasts fuse in a rather homogeneous and synchronous fashion to form myotubes and offer an excellent in vitro system to study the general mechanisms of muscle differentiation.

The availability of the high voltage electron microscope (H.V.E.M.) in recent years for biological research has brought about a new interest in the three dimensional organization of components within whole cells, and the present study on L6 cells was undertaken, using the Jeol-1000 facility, at the University of Colorado in Boulder.
Localization of Atpase Activity in the Sarcoplasmic Reticulum of Myocardium
Authors: Ashraf M. , Jones H. M. , Livingston L. H.
Published: June 2020

Transcellular exchange of various ions takes place via adenosine triphosphatases (ATPases) which are embedded in the cell and its organelle membranes. Due to heterogeneity in the functional roles of myocardial cell membranes, it is generally agreed that different kinds of ATPases exist in the cell. Biochemical evidence indicates that a major ATPase is involved with the Na+-K+ pump and is located in the myocardial cell membrane. Another ATPase, Ca transport ATPase, is localized in the sarcoplasmic reticulum. Little is presently known of the cytochemical localization and distribution of ATPases and their correlation with myocardial cell membranes. In this study an attempt was made to demonstrate the cytochemical distribution of Ca++ ATPase in the myocardium.
Differences in Ultracytochemical Localization of Na-K Dependent Atpase in the Rat Choroid Plexus and Ependyma
Authors: Saburo Nakamura , Donald A. Davis , Thomas H. Milhorat
Published: June 2020

The ventricular ependyma shares a common embryological origin with the choroid plexus (1). These epithelia have many structural and ultrastructural similarities, and both have been considered probable sites of cerebrospinal fluid (CSF) secretion (2,3). The purpose of the present study is to investigate the localization of Na-K dependent (transport) ATPase in rat ventricular ependyma and to compare these findings with the results of previous studies on the choroid plexus.

Adult male Wistar rats were perfused through the heart with 3% depolymerized paraformaldehyde in 0.1M cacodylate buffer (pH 7.3). The brain was rapidly removed and samples of cerebral ependyma with adjacent white matter and choroid plexus were excised and placed in a vial where prefixation continued for 30 minutes at room temperature.
Application of Gaboul Method to the Ultracytochemical Study of Mouse Blood-Brain Barrier
Authors: Castejón Orlando J. , Castejón Haydée V.
Published: June 2020

The cationic dye Alcian blue has been used to demonstrate protein-polysaccharide com plexes at the level of nerve tissue (1,2). The results obtained in the capillary wall when this dye was applied to mouse brain and examined in the electron microscope are the object of the present report.

The central nervous system of normal adult mice was fixed either by vascular perfusion or by immersion with 4% glutaraldehyde-0.1M sodium cacodylate-0.1 M sucrose at pH 6.8 followed by the same procedure using the same fixative but with the addition of 0.5% Alcian blue. After fixation, tissue was immersed in 1% OsO4-0.1M phosphate buffer pH 7.2, dehydrated by graded ethanol and embedded in Araldite. Ultrathin sections were doubly stained with uranyl acetate and lead citrate. The complete procedure has been denominated GABOUL method (3).

The submicroscopic study of cerebral and cerebellar capillaries showed the presence of a thin line of GABOUL positive material attached to the outer layer of the asymmetric luminal membrane of endothelial cells (endocapillary layer) (Fig. 1).
The Measurement of Fluorophosphate-Reactive Esterase Sites in the Liver of Barbiturate Treated Rats Using Quantitative E.M. Autoradiography
Authors: Budd G. C.
Published: June 2020

Male 100 gm Holtzman rats each received 100 mg/Kg of sodium phenobarbital intraperitoneally per day for 4 days. On the fourth day samples of fresh and glutaraldehyde fixed liver were reacted with 10-4 molar tritium labeled diisopropylfluorophosphate (3H-DFP) to permit the measurement of fluorophosphatereactive (FPR) esterase sites using quantitative electron microscope autoradiography (EMARG). The distribution and measured concentrations of FPR sites in the liver of barbiturate treated rats were compared with similar measurements obtained with untreated control rats. Measurements of the density of developed autoradiographic grains (grains/unit area) revealed that in both the treated and control preparations, the FPR sites were concentrated in the rough and smooth endoplasmic reticulum and associated ground cytoplasm of the hepatocytes (RER and SER respectively).
The Ultrastructure of the Gerbil Pineal Gland Under Normal and Experimental Conditions
Authors: Welsh M.L. , Reiter R.J.
Published: June 2020

Multilayered concretions (corpora arenacea), which have been found in the pineal gland of numerous species, may be indicative of the intensity of the secretory processes of the pineal gland. Concretions in the pineal gland of the gerbil (Meriones unguiculatus) occur by the age of 2 months and are a consistent feature in the adult animal. We feel the gerbil pineal provides a good system for examining pineal calcification under controlled conditions.

The ultrastructure of the pineal gland of the gerbil was examined in 1 to 18 month old gerbils which had been maintained in a controlled light environment (LD 14:10). Other gerbils used for this study had been maintained either in constant light environment, had been superior cervical ganglionectomized, or had been blinded by bilateral optic enucleation.
Ultrastructural Study of Human Testicular Biopsies in Infertility
Authors: Siew Shirley , Troen Philip , Nankin Howard R.
Published: June 2020

Testicular biopsies were obtained from six young male subjects (age range 24-33) who complained of infertility and who had clinical evidence of oligospermia. This was confirmed on histological examination which showed a broad spectrum from profound hypospermatogenesis to relatively normal appearing germinal epithelium. Thickening of the tubular walls was noted in half of the cases and slight peritubular fibrosis in one. The Leydig cells were reported as normal or unremarkable.

Transmission electron microscopy showed that the thickening of the supporting tissue of the germinal epithelium was caused more by an increase in the thickness of the layers of the lamina propria than of the tubular wall itself. The changes in the basement membrane of the tubular wall consisted mostly of a greater degree of infolding into the tubule and some reduplication which gave rise to a multilayered appearance.
Structural Microtubules in Hind-Gut Epithelial Cells of the Mosquito
Authors: Cerreta Joseph M.
Published: June 2020

In an ultrastructural study of the metamorphosis of the hind-gut of the mosquito, Culex pipiens Linn., microtubules were observed to form complexes with the apical and basal plasma membranes in cells of the ileum and the rectum. The larval and early pupal hind-gut consists of three regions; an ileum, a colon and a rectum. Morphologically the epithelium of the ileum and rectum are identical consisting of large squamous cells which are highly folded. The epithelium of the colon which lies between the other two regions is comprised of large cubodial cells with polytene nuclei. The entire hind-gut is lined by a thin intima. During metamorphosis the cells of the colon disintergrate and their fragments are shed into the hemocoel.
Ultrastructural Studies of Isolated Polytene Chromosomes by Scanning Electron Microscopy
Authors: Payne Michael B.
Published: June 2020

Scanning and transmission electron microscopy studies of mitotic chromosomes have demonstrated that these chromosomes are composed of single intricately coiled and folded chromatin fibers 200-300 A in diameter (1). Transmission electron microscopy studies (2) have shown similar fibers in dipteran polytene chromosomes. It has been proposed that these fibers are extended in the less densely appearing interband regions and become more tightly coiled or folded at specific sites to produce the densely appearing banded regions (3). With the scanning electron microscope it is now possible to observe the characteristic appearance of the chromatin fibers in the band and interband regions of isolated intact polytene chromosomes. Furthermore, the morphology of the nucleolus and Balbiani rings can be observed as specialized structures in the chromosome.
Quantitative Freeze Fracture Studies of Gap Junctions in Somatic Cell Hybrids, Their Parents, and Revertants
Authors: Larsen W. J. , Azarnia R. , Loewenstein W. R.
Published: June 2020

Although the physiological significance of the gap junction remains unspecified, these membrane specializations are now recognized as common to almost all normal cells (excluding adult striated muscle and some nerve cells) and are found in organisms ranging from the coelenterates to man. Since it appears likely that these structures mediate the cell-to-cell movement of ions and small dye molecules in some electrical tissues, we undertook this study with the objective of determining whether gap junctions in inexcitable tissues also mediate cell-to-cell coupling.

To test this hypothesis, a coupling, human Lesh-Nyhan (LN) cell was fused with a non-coupling, mouse cl-1D cell, and the hybrids, revertants, and parental cells were analysed for coupling with respect both to ions and fluorescein and for membrane junctions with the freeze fracture technique.
The Value of Electron Microscopy in the Differential Diagnosis of Amebic Meningoencephalitides.
Authors: Julio Martínez A. , Fultz Doris G. , Armstrong Caroline E. V.
Published: June 2020

Ultrastructural study of trophozoites and cysts in amebic encephalitides (1-4) have provided significant information pertaining to pathogenesis as well as clarification of taxonomic criteria (e.g. species, genera, etc). The use of tissues previously fixed in formalin and embedded in paraffin, then reprocessed and embedded in plastic for electron microscopic studies is useful in the evaluation of morphological features of trophozoites and cysts of these pathogenic free-living amebas. Even though the tissues disclose some post-morten autolytic alterations and distortions, trophozoite and cyst preservation is satisfactory for identification, giving excellent morphological information. Details of the overall form, which may have a role in pathogenicity, including cytoplasmic processes and projections, organelles and cyst walls, may be revealed.
The Virus in Oral Condyloma Acuminatum
Authors: Gysland W. B. , Reimann B. E. F. , Shaffer E. L.
Published: June 2020

Condyloma acuminatum, a wart type which usually occurs in the anogenital areas of humans, has occasionally been reported to occur in the oral cavity.Papilloma virus particles have been demonstrated in lesions of anogenital location. This report is concerned with the findings of similar virus particles in abundance in oral condylomata.

Specimens were excised from the palate of the patient, fixed in glutaraldehyde and osmium tetroxide and post-contrasted with uranyl acetate and lead citrate.

In 4 out of 5 sites, with a parakeratotic surface appearance, intranuclear viral particles were found. The virus particles are circular (23%) to slightly oval in shape with a mean diameter of 46.8 x 49.3 nm (minimum diameter 45 nm, maximum diameter 52 nm).
Ultrastructural Changes in the Mammary Epithelial Cell Population During Neoplastic Development Induced by A Chemical Carcinogen.
Authors: Russo J. , Isenberg W. , Ireland M. , Russo I.H.
Published: June 2020

The induction of rat mammary carcinoma by the chemical carcinogen DMBA is used as a model for the study of the human disease (1). We previously described the histochemical changes that occur in the mammary gland of DMBA treated animals before the earliest manifested histological change, the intraductal proliferation (IDP), was observed (2). In the present work, we demonstrate that a change in the stable cell population found in the resting mammary gland occurs after carcinogen administration.

Fifty-five day old Sprague-Dawley virgin female rats were inoculated intragastrically with 20mg of 7,12-dimethylbenz(a)anthracene (DMBA) in 1ml sesame oil. Non-inoculated, age-matched females were used as controls. Mammary glands from control and inoculated rats were removed weekly from the time of inoculation until 60 days post-inoculation. For electron microscopy, the glands were immersed in Karnovsky's fixative, post-fixed in 1% OsO4, dehydrated, and embedded in an Epon-Araldite mixture. Thick (lμ) sections were stained with 1% toluidine blue and were used for selecting areas for ultrastructural study.
Detection of Viral Antigens in Mouse and Rat Tumor Cells by Immunoelectron Microscopy Following Periodate-Lysine-Paraformaldehyde (PLP) Fixation
Authors: Ohtsuki Y. , Seman G. , M. Bowen J. , Scanlon M. , Dmochowski L.
Published: June 2020

Recently, periodate-lysine-paraformaldehyde (PLP) fixation was reported for immunoelectron microscopy (1). In PLP fixation, carbohydrates are oxidized by periodate and cross-linked by lysine; paraformaldehyde stabilizes proteins and lipids. By using PLP fixation, intracytoplasmic type A viral antigens have been previously demonstrated by immunoperoxidase labeling (2). In the present study, PLP fixation has been applied for the detection of the same antigens in mouse mammary tumor culture cells by both immunoferritin and immunoperoxidase methods. Rabbit anti-intracytoplasmic type A virus serum (anti-A), kindly provided by Dr. M. Muller (3), rabbit anti-strain A mouse mammary tumor virus (anti-MMTV) and preimmune rabbit serum as control were used to detect viral antigens in cells of C3H/HeJ strain mouse mammary tumor culture. Attempts have been also made to demonstrate peroxidase labeling of type C virus particles in frozen sections of an SD-MSV-induced NZB rat bone tumor tissue by rabbit anti-MuLV serum.
An Ultra-Structural Study of Human Melanoma in Vivo and Vitro
Authors: Gaylor James R. , Schafer Fredda , Nordquist Robert E.
Published: June 2020

Several theories on the origin of the melanosome exist. These include the Golgi origin theory, in which a tyrosinase-rich protein is "packaged" by the Golgi apparatus, thus forming the early form of the melanosome. A second theory postulates a mitochondrial origin of melanosomes. Its author contends that the melanosome is a modified mitochondria which acquires melanin during its development. A third theory states that a pre-melanosome is formed in the smooth or rough endoplasmic reticulum. Protein aggregation is suggested by one author as a possible source of the melanosome. This fourth theory postulates that the melanosome originates when the protein products of several genetic loci aggregate in the cytoplasm of the melanocyte. It is this protein matrix on which the melanin is deposited. It was with these theories in mind that this project was undertaken.
Morphometric Analysis of the Hepatocytes from Fish Exposed to Arsenic
Authors: Sorensen Elsie M. B.
Published: June 2020

The detoxification capacity of the liver is well documented for a variety of substances including ethanol, organic pesticides, drugs, and metals. The piscean liver, although less enzymatically active than the mammalian counterpart (1), contains endoplasmic reticulum with an impressive repertoire of oxidizing, reducing, and conjugating abilities (2). Histopathologic changes are kncwn to occur in fish hepatocytes following in vivo exposure to arsenic (3); however, ultrastructural changes have not been reported. This study involved the morphometric analysis of intracellular changes in fish parynchymal hepatocytes and correlation with arsenic concentration in the liver.

Green sunfish (Lepomis cyanellus, R.) were exposed to 0, 30, or 60 ppm arsenic (as sodium arsenate) at 20°C for 1, 2, or 3 week intervals before removal of livers for quantification of the arsenic burden (using neutron activation analysis) and morphometric analysis of ultrastructural alterations. Livers were cut into 1 mm cubes for fixation, dehydration, and embedding.
Stem/Edx Analysis of A Bone-Bioglass Interface
Authors: Hren J. J. , Johnson P. F. , Bates S. R. , Hench L. L.
Published: June 2020

Previous studies have established that a special glass (45 w/o SiO2, 24.5 w/o CaO, 24.5 w/o Na20, 6.0 w/o P2O5), can form a bond with living bone (1) In-vitro studies suggest that an amorphous gel composed of Si02, CaO, and P2O5serves as a transition layer between the bioglass and the bone. The present study sought to measure the in-vivo composition of this layer using a Phillips EM 301 with a specially designed specimen holder, and an Ortec EDX and detector (2).

A sample (5 x 1 x 4 mm), was implanted in a rat tibia for 3 weeks, blocks obtained, and fixed in gluteraldehyde*. Sections were cut much thicker than normal, resulting in a loss of histological detail, but a higher X-ray production. No OsO4or heavy staining metal was used.
Localization of Lysosomal Enzymes in Herpesvirus-Infected Cells by Electron Microscope Cytochemistry
Authors: Smith J. D. , Harven E. de
Published: June 2020

Evidence of increased lysosomal enzyme content and activity has been reported following infection by a number of herpesviruses, but its significance remains unclear. One hypothesis holds that lysosomal enzymes, as part of host cell defenses. inactivate cytoplasmic viral progeny so that most released particles are noninfectious and infectivity remains highly cell associated. Such a pattern is characteristic of varicellazoster (VZ), and indeed electron microscope cytochemical studies have revealed that cytoplasmic VZ particles are often located within lysosomes (1). It was of interest to determine whether there is a less direct relationship between lysosomes and progeny virus in herpesvirus systems where infectivity is not closely cell-restricted. The present paper describes acid phosphatase and aryl sulfatase localizations in WI-38 cells (diploid human lung fibroblasts) infected with either herpes simplex virus (HSV), strain HF, or human cytomegalovirus, strain AD-169.
The Structure of the Aleutian Disease Antigen
Authors: Sarkar N.H. , Notani G.W. , Kenyon A.J.
Published: June 2020

Aleutian disease of mink is transmissible by cell free extracts of affected mink tissues. Two antigenic components (Ag-1 and Ag-2) have been isolated from infected mink tissues by Kenyon and his associates. The relationships of the two antigens with the structural components of the Aleutian disease virus (ADV) have not yet been established; furthermore the details of the virus structure is lacking.

We have prepared antigens from liver extracts of mink infected with Connecticut as well as Canadian strain of ADV. One of the antigen prepared from Connecticut strain of ADV contained primarily ring structures (13 nm in diameter) and few particules having icosahedral symmetry (27 nm in average diameter).
An Ultrastructural Study of Chronic Pyelonephritis in Macaca Arctoides
Authors: Smith T.W. , Roberts J.A. , Martin B.J.
Published: June 2020

Chronic pyelonephritis is one of the most common diseases of the kidney and accounts for a sizeable number of cases of renal insufficiency in man, however its pathogenesis requires further elucidation. Transmission electron microscopy may serve as a uniquely effective means of observing details of the nature of this disease. The present paper describes preliminary results of an ultrastructural study of chronic pyelonephritis in Macaca arctoides (stumptail monkey).

The infection was induced in these experiments in a retrograde fashion by means of a unilateral catheterization of the left ureter whereby an innoculum of 10 cc of broth containing approximately 2 billion E. coli per cc and radio-opaque dye were injected under pressure (mimicing vesico-ureteric reflux).
Lead Staining by Ion Implantation
Authors: Dobbs B. C.
Published: June 2020

Ion implantation has been effectively used as a stain for biological specimens prepared for electron microscope examination (1,2). We have used this method of staining on critical point dried T4 bacteriophage. The lead ions proved to be a non-specific stain. However, these ions are also highly susceptible to radiation damage (3,4). With precautions, the specimens may be tilted to the implanting beam so that the implanted ions provide an ultrafine uniform shadowing for the specimen. Also, tilting effectively increases the thickness of the support film.

400 mesh copper grids were covered with a 120Å formvar film, then carbonized with 50Å of carbon to provide the specimen support. The bacteriophage were then critical point dried (5) by first replacing the specimen water with ethanol, the ethanol by Freon 113 and the Freon 113 by Freon 13 which was then dried in a high pressure container.
Wafer Embedment to Facilitate Light Microscope Selection of Specimens for Ultrathin Sectioning
Authors: Romanovicz Dwight K. , Hanker Jacob S.
Published: June 2020

An unfortunate consequence of the high magnification achieved in electron microscopy is the inability to scan large areas of tissue or locate structures which are small and of infrequent occurrence. The standard procedure is to section repeatedly, hoping that an area of interest will be encountered. However, this time-consuming practice can be avoided by the use of a special embedding platform which permits the embedment of tissue for examination by light microscopy prior to sectioning.

Aldehyde-fixed tissues are cut into 10μm sections with a Vibratome or into 20-30μm sections with a Sorvall TC-2 tissue sectioner. At this point optimal sections may be selected on the basis of a particular morphological feature, for which a light methylene blue or Alcian blue stain may be employed; or selection may be based upon activity of a cytochemical enzyme stain, particularly one which involves 3,3'-diaminobenzidine (DAB).
Ultrastructural Studies on L1210 Cells Sensitive or Resistant to Actinomycin-D.
Authors: Calvelli T. A.
Published: June 2020

The L1210(V)gln-cell line, which requires glutamine for growth, was established as a suspension culture by Hutchison et al. (1) from an ascites tumor maintained in BD2F1mice (C57BL X DBA/2). A variety of particles having the morphology of intracytoplasmic-A, type-B and type-C oncornaviruses have been observed in the solid, ascitic (2;3) and tissue culture forms(4;5;6) of the L1210 cells. A subline of the L1210(V)gln-line, 2000-fold resistant to actinomycin-D exhibits low tumorigenicity and is immunogenic inBD2F1mice.

Cells of the parent, drug-sensitive line are primarily of lymphoid morphology, i.e. spherical with a large central nucleus. Occasionally they have lobulated or multiple nuclei, marginated heterochromatin, and a single prominent nucleolus. Although some rough endoplasmic reticulum is visible in sensitive cells, the majority of polysomes are found free in the cytoplasm.
Living Plants Continue to Grow After Examination by Scanning Electron Microscopy
Authors: Sowers Arthur E.
Published: June 2020

It has been found that, within the constraints and limitations described below, the same individual living plant, Urtica pilulifera (common name - Stinging Nettle), continues to grow after repeated brief (6 minute) examination by conventional scanning electron microscopy. Fig. 1-3 show the simultaneous initiation and synchronous elongation of many epidermal hairs in the same area on the first internode of the same plant. The time interval between examinations was 24 hours.

Seeds of Urtica pilulifera were germinated in vermiculite, the above ground part separated from the roots by a perpendicular cut with a razor and transferred to an hydroponic solution. Germination and transfer of the above ground parts were timed such that the plants were at a stage of morphogenesis shown in Fig. 4 at the start of the daily SEM examinations.