bluuebunny/crossref_metadata_2025 huggingface dataset:
Microstructure of Al-Cu thin-film interconnect
Authors: Rose J. H. , Lloyd J. R. , Shepela A. , Riel N.
Published: June 2020

The precipitate structure of bulk aluminum alloys was heavily studied with x-ray diffraction commencing in the 1930s and via direct observation with the development of transmission electron microscopy (TEM) techniques in the 1950s. In 1970, recognition of the electromigration performance benefits of Cu additions to Al interconnect in integrated circuit devices precipitated studies on Al-Cu thin films. However, the microstructure of these films remains only partially known, in part due to the many process and interconnect geometry variables. In particular, there has been minimal attempt to study films which mimic as closely as possible the environment and thermal history of real interconnect (prior studies typically have examined unpatterned or unpassivated films.) In the present work, Al-Cu films in standard life test devices have been studied. This work is directed at understanding the evolution of microstructure during device processing and life testing and application of this knowledge to a better understanding of the role of microstructure in electromigration in Al-Cu interconnect. The present contribution describes initial microstructural observations on a variety of annealed samples.
Cathodoluminescence and electron-beam-induced current investigations of semiconductor materials and structures for optoelectronic integration
Authors: Fitzgerald E.A.
Published: June 2020

Mismatched semiconductor heteroepitaxy has been of interest for both high speed electronics and optoelectronic integration. The largest impact of mismatched epitaxy would be the integration of mature Si electronics with light-emitting III-V materials, such as GaAs. However, the lattice constant of Si is much smaller than the lattice constant of direct band gap III-V materials; therefore, integration through epitaxy introduces many misfit-relieving dislocations, which can terminate at the surface (threading dislocation segments). Any optical devices fabricated from this material degrade rapidly due to the high dislocation density. Cathodoluminescence (CL) and electron beam induced current (EBIC) are extremely valuable in relating optoelectronic quality to microstructure and processing.
Oxygen bubble formation and evolution during oxygen implantation and annealing of silicon-on-insulator material
Authors: Krause S J. , Lee J.D. , Chen B.L. , Seraphin S. , Cordts B. , Roitman P.
Published: June 2020

Silicon-on-insulator (SOI) material fabricated by high dose oxygen implantation (SIMOX) is a material increasingly used for higher speed and radiation hard circuits. During implantation a variety of structural changes occur, including the formation of defects, bubbles, precipitates, and the buried oxide layer. The topic of bubble formation and evolution has received only limited study. Sjoreen et al. first reported the presence of spherical, randomly distributed precipitates near the top surface of the silicon layer. El-Ghor et al. further examined these precipitates and proposed that they were cavities filled with oxygen. Maszara confirmed the presence of spheroids filled with oxygen in the silicon top surface region in the 1mA cm-2 as-implanted samples. In this work, transmission electron microscopy (TEM) techniques were used to investigate the effect of implantation conditions on the bubble formation and the effect of subsequent annealing conditions on the evolution of bubbles.
TEM characterization of phosphorus-implanted silicon
Authors: David Theodore N. , Knoch Lynnita , Christiansen Jim
Published: June 2020

Implantation of dopant-species into silicon can result in the formation of amorphous regions, interfaces and extended defects (in the silicon). The presence of these defects can cause modification of dopant distributions, and the rise of leakage currents in p-n junctions. An understanding of the behavior of implant-induced defects and their effect on dopant-distributions is therefore relevant. Such understanding could lead to better defect and dopant control and therefore to more reliable device performance. In this study, a correlation between dopant distributions and damage in implanted silicon, is investigated.

The samples investigated were p-type (14-20 Ω-cm) silicon (100) wafers implanted with phosphorous at 180 kev to a dose of 1x1016 cm-2. The implants were performed at room temperature. Post-implant annealing was performed (by rapid-thermal annealing “RTA“) at 800°C for 15 seconds. SIMS (secondaryion mass-spectrometry) and XTEM (cross-section TEM) analysis were performed on as-implanted and annealed samples. Cross-section TEM specimens were made in the 110 geometry. TEM investigation was performed using a JEOL JEM 200CX transmission electron microscope operating at 200 kV. SIMS analysis was performed using an Atomika A-DIDA quadropole instrument with 8 keV O2+ primary ions.
High-resolution TEM observation of displacement cascades in krypton ion irradiated silicate minerals
Authors: Wang L.M. , Miller M.L. , Ewing R.C.
Published: June 2020

Radiation induced amorphization (or metamictization) happens naturally in many U and Th containing minerals due to alpha decay of the radioactive actinides over the lengthy geological times. It has been shown recently that the process can be simulated very efficiently by ion beam irradiation. Detailed study at atomic level on this crystalline to aperiodic transition is necessary for the fundamental understanding of the process which is important to several technological fields, such as nuclear waste disposal and ionbeam modification of ceramic materials.
Comparative Oxidation Studies of Polycrystalline HP and CVD Silicon Carbides by TEM
Authors: Bow J.S. , Kim M.J. , Carpenter R.W.
Published: June 2020

The excellent oxidation resistance of SiC at high temperature results from formation of a protective SiO2 layer in a strongly oxidizing environment. The oxide layer is often initially amorphous, may transform to a crystalline phase for extended reaction time, especially crystobalite above 1200°C. Our objective is use of high resolution electron microscopy methods to determine the oxide layer microstructure dependence on SiC substrate type, and especially to investigate existence of an intermediate Si-O-C phase between the oxide layer and substrate.
Pyramidal Slip in β Boron
Authors: Vanderwalker D.M.
Published: June 2020

Boron is a semiconductor which has applications as a high energy fuel and coating material. Thus, one can assume there is an interest in the structural andelectronic properties. Boron has been found to crystallize into several structures. The α rhombohedral boron was reported to have lattice parameters of a = 5.057 A, α = 58°4. (hexagonal coordinates a = 4.908 A, c = 12.567 A) β Rhombohedral boron, the high temperature phase, has been found to have lattice parameters a = 10.145 A, α = 65° or in the hexagonal system a = 10.944 A, c = 23.811 A with 320 atoms per unit cell.
TEM Characterization of a Modulated β Phase in Polycrystalline Dicalcium Silicate
Authors: Kim Y. J. , Nettleship I. , Kriven W. M.
Published: June 2020

Five polymorphs are known as major phases in pure dicalcium silicate (Ca2SiO4) at atmospheric pressure—α, α'H, α'L, β and γ. Fully dense pellets were prepared by sintering chemically prepared powders in the temperature range of 1300 to 1400°C for 1 to 12 hours. Their phases and microstructures were studied by TEM through selected area diffraction patterns (SADP's) and imaging techniques.
Growth and characterization of aluminum nitride thin films
Authors: Grant Norton M. , Kotula Paul G. , Barry Carter C.
Published: June 2020

Pulsed-laser ablation has been widely used for the fabrication of thin films of multicomponent oxide ceramics. More recently the technique has been successfully used to deposit highly oriented thin films of aluminum nitride (AIN). AIN thin films are of interest for a number of potential applications. These applications include heat sinks for high-power microcircuit applications and insulating and passivating layers in semiconductor devices. For all the proposed applications it is important to be able to produce highly oriented, dense crystalline films. It is also important that these films be essentially defect free, as for example, phonon scattering by defects and impurities can severely limit thermal conductivity.
Development of Crystallinity in Turbostratic Boron Nitride Derived from Polymeric Precursors
Authors: Qiu X. , Datye A. K. , Borek T. T. , Paine R. T.
Published: June 2020

Boron nitride derived from polymer precursors is of great interest for applications such as fibers, coatings and novel forms such as aerogels. The BN is prepared by the polymerization of functionalized borazine and thermal treatment in nitrogen at 1200°C. The BN powders obtained by this route are invariably trubostratic wherein the sheets of hexagonal BN are randomly oriented to yield the so-called turbostratic modification. Fib 1a and 1b show images of BN powder with the corresponding diffraction pattern in fig. 1c. The (0002) reflection from BN is seen as a diffuse ring with occational spots that come from crystals of BN such as those shown in fig. 1b. The (0002) lattice fringes of BN seen in these powders are the most characteristic indication of the crystallinity of the BN.
HREM image simulation of a twin intersection in CVD diamond
Authors: Ning X. J. , Yang J. , Pirouz P.
Published: June 2020

Chemically vapor deposited diamond was grown on a molybdenum substrate. A high density of twins (∑=3) and twin intersections were found in die diamond film. The twin intersections in silicon may result in the formation of a hexagonal phase in the region of intersection. Hexagonal diamond has previously been reported in high pressure experiments and in some meteorites. Here we present a type of intersection which is very common in CVD diamond as well as in other materials with the diamond, or the zincblende, structure grown epitaxially on various substrates. In this type of intersection the two twins do not cross each other; rather, one twin (T1) stops the propagation of another twin (T2).
Interfacial Structures in the Nb/MgO/Nb/Al2O3 Superlattice
Authors: Li D. X. , Pirouz P. , Heuer A. H. , Yadavalli S. , Flynn C. P.
Published: June 2020

Nb/MgO/Nb/Al2O3 superlattices were prepared by MBE growth of Nb and MgO films on a (012)Al2O3 sapphire substrate. Cross sectional HREM specimens were prepared using standard techniques involving mechanical grinding to a thickness of 0.13 mm, dimpling to a thickness of 20 μm and ion beam milling at 6 kV. The samples were subsequently examined in a top-entry JEOL 4000EX high resolution electron microscope with a point-to-point resolution of ∼0.19 nm. Image simulations were performed using the SHRLI programs developed by O'Keefe.
The Effect of Large-Angle Tilting on the Electron Diffraction Pattern of Chrysotile Asbestos
Authors: Ling P. , Kawayoshi H. A. , Martinez L. , Tien T.
Published: June 2020

The structure of chrysotile asbestos is very unique. Morphologically, individual filaments can be thought of as thin sheets which have been rolled into cylinders or scrolls. Because of this structure, the electron diffraction pattern is very unusual and contains (OkO) and (001) reflections along the zero layer line and characteristic flared reflections of the type (hkO) , where h and k are odd. In practice, chrysotile asbestos is commonly identified by 7.3 Å (002) reflection, a 4.6 Å (020) spacing, and a repeat layer spacing of 5.3 Å.
An Electron Optician's View on the Electron Microscope
Authors: LePoole J. B.
Published: June 2020

This is the part, that decides the image quality of the microscope. For good resolution, the aperture angle should be as large as possible. Since the important lens errors increase rapidly with the aperture angle, the design should aim a reduction of the errorcoefficients.

A good way to reduce these coefficients is to increase the excitation (Ampère turns). Nowadays all objective lenses are designed for high excitation. It means that prevention of saturation anywhere in the ironcircuit plays an important role in the design. It can be shown that by using a symmetric magnetic circuit the excitation of a lens can be approximately doubled without additional problems.
A High-resolution electron microscopy study of Rh/Ce on silica
Authors: Krause K. R. , Schmidt L. D. , Schabes-Retchkiman P. S.
Published: June 2020

Rhodium is responsible for the catalytic removal of NOx from automobile exhaust and along with other metals, is found in modern catalytic converters. Cerium is an important additive to these catalysts and has been suggested to promote the water-gas shift reaction, to provide oxygen storage, and to improve the thermal stability of the support. We have examined the microstructure of Rh/Ce on silica with several techniques and present results from HREM which provide direct evidence of interaction between Ce and Si in these catalysts.

Planar SiO2 supports were prepared by vacuum depositing ∼20nm of Si on formvar coated gold TEM grids and heating the grids in O2. Rh and Ce were then vacuum deposited on the SiO2 and the grids were heated in H2 at 650°C to disperse the film into particles. The microstructures were examined with TEM. The samples were then heated in O2 at 650°C and the same areas were again examined with TEM.
Observation of in situ reduction of ceria-supported rhodium catalysts by electron beam irradiation
Authors: Pan M.
Published: June 2020

In rhodium catalysts supported on lanthanide oxides, significant difference in rhodium dispersions has been observed between cerium dioxide (CeO2) and sesquioxides (Ln2O3) by high resolution electron microscopy (HREM). This has been attributed to the different behaviors of the oxide supports during their impregnation with aqueous solution of rhodium nitrate (Rh(NO3)3). In the acid media, cerium dioxide has a higher reducibility while the sesquioxides have a higher solubility. So studying the catalyst precursor and the reduction process can provide an understanding of its interaction with the support during the impregnation stage and the metal dispersion on the oxide supports. Results on cerium dioxide support are presented here.

The catalyst precursor was prepared by incipient wetness impregnation method as reported elsewhere. The rhodium loading was 2.4 wt%. The HREM work was performed in JEOL 4000EX electron microscope (point resolution of 1.7 Å). The typical current density used during observation was ∼6.5A/cm2 at the specimen. The vacuum in the column of the microscope was ∼10-7 torr.
Advances in microscopy of polymers: A FESEM and STM study
Authors: Chen R.T. , Jamieson M.G.
Published: June 2020

Microscopy has played a major role in establishing structure-process-property relationships in the research and development of polymeric materials. With advances in electron microscopy instrumentation (e.g., field emission SEM - FESEM) and the invention of new scanning probe microscopes (e.g., scanning tunneling microscope - STM), resolution of structures or morphologies down to the nanometer scale can be achieved with ease. This paper will focus on the application of FESEM and STM in order to understand the structure of commercial polymeric materials. Characterization of polymers using other microscopy techniques such as TEM, thermal optical microscopy and atomic force microscopy (AFM) will also be discussed.

The polymeric materials evaluated in this study include membranes, liquid crystalline polymer (LCP) fibers, multiphase polymer blends and polymer films or coatings. In order to minimize beam damage and maximize contrast for surface detail in beam sensitive polymers, low voltage SEM (LVSEM) was performed on a JEOL 840F field emission SEM.
High resolution electron microscopy of polymers near surfaces
Authors: Martin David C. , Wilson Patricia M.
Published: June 2020

The molecular organization of polymer solids near surfaces is important for understanding properties such as adhesion, friction, mass transport, and fracture initiation. Materials comprised of small molar mass atoms or molecules can exhibit detailed reorganization near free surfaces. It might be expected that the perturbing influence of a free surface on structure would be even more pronounced for materials comprised of large macromolecules. Local information about structure near surfaces of inorganic materials is often obtained by High Resolution Electron Microscopy (HREM). Unfortunately, direct imaging of local structure in solid polymers by HREM is problematic because of the extreme sensitivity of organic molecules to electron beam irradiation. However, the systematic application of low dose techniques and the development of stable high voltage instrumentation has made it possible to apply HREM techniques to certain polymer systems. Here, we describe our recent studies which have concerned the microstructure of polymer solids near surfaces. In these experiments we used a JEOL 2000 EX TEM operating at 200 kV and a JEOL 4000 EX TEM operating at 400 kV.
Structure and Function of Sertoli Cells
Authors: Dym M.
Published: June 2020

The Sertoli cells perform an impressive array of functions in the testis. It is possible that the full control of germ cell differentiation is mediated by this elaborate cell type (Fig. 1). On the basis of its shape and strategic position within the seminiferous epithelium the functions of (1) support and nutrition have been assigned. Fawcett and Phillips (J. Reprod. Fert. 6: 405, 1969) demonstrated that the Sertoli cells engineer the (2) release of late spermatids into the tubule lumen; other data suggest that they are instrumental in the migration of the germ cells from the basal lamina to the lumen. Tight junctions between adjacent Sertoli cells subdivide the seminiferous epithelium into two compartments, basal and adluminal. These junctions form the (3) morphological basis of the blood-testis barrier . The Sertoli cells are capable of (4) phagocytizing vast numbers of degenerating germ cells and sperm residual bodies.
Energy Dispersive X-Ray Examination of Cell Surface Antigen Sites
Authors: Barber T. A.
Published: June 2020

Immunolabeling for transmission and scanning electron microscopy allows examination at high resolution of cell surface antioen sites. In procedures used with the scanning electron microscope significant problems are associated with non-specific labeling, aggregation of labeled particles, the attachment of label particles to cell surfaces by comparatively weak antigenantibody bonds, and quantitation of amounts of immunologic marker at a cell's surface. In the light of recent developments in elemental analysis of biological materials through the use of x-ray snectra (1), it seems desirable to explore the use of energy dispersive x-ray analysis (EDXA) in the examination of cell surface antigen sites.
Cytochemical Localization of Polysaccharides in Diplodia Maydis With Thiosemicarbazide : Evaluation of Three Fixatives For Pa:Tsc:Os Reaction
Authors: Murphy Judith A. , Thompson Mary R. , Pappelis A.J.
Published: June 2020

In an attempt to identify polysaccharide components in thin sections of D. maydis, procedures were employed such that a PAS localization could be carried out. Three different fixatives were evaluated ie. glutaraldehyde, formaldehyde and paraformaldehyde. These were used in conjunction with periodic acid (PA), thiosemicarbazide(TSC), and osmium tetroxide(Os) to localize polysaccharides in V. maydis using a pre-embedded reaction procedure. Polysaccharide localization is based on the oxidation of vic-glycol groups by PA, and the binding of TSC as a selective reaction center for the formation of osmium black. The reaction product is sufficiently electron opaque, insoluble in lipids, not altered when tissue is embedded, and has a fine amorphous character.
Laminar Organization of Leptomeric Organelles in Extraocular Muscle
Authors: Philips Gloria H. , Davidowitz Jacob , Pachter Bruce R. , Breinin Goodwin M.
Published: June 2020

Cross-striated structures known as leptomeric organelles, laminated structures or microladders have been reported in mature and developing muscle cells, in extrafusal and intrafusal fibers, and in skeletal, cardiac and extraocular muscle: varying functional significance has been attributed to them, including contractile properties, Z band anchor, and microtendonous shock absorber, among others. These striated bodies are known to occur in widely assorted sizes, either singly or in conglomerates wherein the striations of the respective components are disparately oriented. In the present study, rabbit superior rectus was prepared by standard EM methods; the numerous leptomeric organelles observed in this tissue were similar to those previously described. The organization of large conglomerates of these structures were analyzed in serial sections.
Cilia Microtubule Deformation: A Preliminary Report
Authors: Redding R.
Published: June 2020

Various hypotheses for the mechanism of ciliar motility either purport or oppose the concept of microtubule contraction. Recent literature supporting the Sliding Microtubule Model has established that microtubule doublets move relative to one another during the process of bending. Satir (1968) concluded that there is no change of length in the doublets during bending of cilia. He based his conclusion upon: (1) circular relationships and (2) a two dimensional configuration of the microtubules. Accuracy of the circular relationships is dependent upon how close the approximation is to the true curvilinear relationship expressed by a ciliutn. Cross sectional rotation during bending may limit the validity of two dimensional analysis. This communication is a preliminary report on a new, three dimensional approach for determining the deformational characteristics of elongation or shortening of microtubules as they may be expressed in cilia.
Variations in Mitochondrial Reaction Products From 3,3'-Diaminobenzidine Oxidation At Various Ph Values
Authors: Allen Shannon W. , Hoshino Yoshinobu
Published: June 2020

Since the initial demonstration of cytochrome oxidase via cytochrome c with 3,3'-diaminobenzidine by Seligman et al. (1), numerous investigations using the technique have been reported. This report deals with incubating media pH variations and resulting characteristics of DAB oxidation reaction product deposition. In addition the localization of initial reaction foci, viz. active sites, was attempted by these variations.

Small slices of rat liver were rinsed in 0.05M phosphate buffer-7.5% sucrose (pH 7.0, 4°C), minced, rinsed again and immediately incubated 15 min to 1 hr at 22°C. The medium consisted of 10 ml 0.1M Tris-HCl buffer containing 5 mg of DAB-4 HC1. The range of pH tested was from pH 6.8 to 9.6. The specific pH values tested were 6.8, 7.0, 7.2, 7.4, 7.6, 7.8, 8.0, 8.2, 8.4, 8.6, 9.0, and 9.6. Following incubation, the tissues were rinsed in buffer solution and osmicated 1 hr at 22°C in 2% osmium tetroxide.
A Micromethod for Performing Ferritin Labeling Studies on Mouse Mammary Tumor Cells
Authors: Hixson D. C. , Bowen J. M.
Published: June 2020

Immunoelectron microscopic studies on mouse mammary tumor cells (MMT cells) are complicated by the epithelial nature of these cells. Numerous intercellular junctional complexes make preparation of single cell suspensions difficult without the use of proteolytic enzymes which may alter or destroy cells and/or viral antigens. Furthermore, these junctional complexes make MMT cells sensitive to disruptive sheer forces which arise during rigorous washing involving pipetting and centrifugation. Finally, studies on MMT cells producing mouse mammary tumor virus (MMTV) often necessitate the use of primary cultures of hormone stimulated cells. Such cultures can only provide limited quantities of cells which may be insufficient for standard immunological methods.
Asymmetric Distribution of Membrane-Glycogen Complexes in Multiply Innervated Fibers of Rabbit Extraocular Muscle
Authors: Davidowitz Jacob , Pachter Bruce R. , Philips Gloria , Breinin Goodwin M.
Published: June 2020

Membrane-glycogen complexes were recently described in multiply innervated fibers (MIF) of extraocular muscle (EOM) of mature rabbits (1,2). They have not been reported in EOM of other species. The present study finds that such complexes are not evenly distributed along the length of MIF but are largely confined to the ends of these fibers and well removed from the muscle's thickened belly portion where sampling might most likely be concentrated. The m. superior rectus of prepubertal (2 Kg. ) New Zealand white rabbit was embedded whole and serially sectioned at 5 microns (3). Fibers along the orbital surface of the muscle were followed by light microscopy whereby the endings of MIF could be detected. The locus of MIF populations within the muscle was determined, and approximately 30 samples per fiber were taken for EM examination. Two major populations of MIF were observed among the orbital surface fibers.
A Study of the Structure of the Cell Wall of Spirillum Serpens Using Frozen, Hydrated Specimens
Authors: Taylor Kenneth A. , Grano David A. , Chiu Wah
Published: June 2020

Based on chemical and electron microscopic studies (Buckmire and Murray, 1970), the cell wall of Spirillum serpens VHA, a Gram-negative bacterium, is composed of several components including protein, lipopolysaccharide, and peptidoglycan. By a gentle heating of the bacteria at 60°C, the outermost components of the cell wall are separated from the rest of the cell, and can be purified by simple procedures. In the negatively stained preparations, it has been shown by Buckmire and Murray that these components appear in both lamellar and tubular forms made up of identical particles in a closely packed hexagonal arrangement. These particles are approximately 90 Å in diameter, with a center-to-center spacing of approximately 150 Å, and are connected by Y-shaped links.
Fine Structural Changes of the Porcine Oviductal Epithelium During Late and Term Pregnancy
Authors: Nayak R. K. , Albert E. N.
Published: June 2020

The characteristic ultrastructural changes in the ciliated and secretory cells of the tubal epithelium of adult gilts during the estrous cycle have been described (1). Earlier light microscopic studies revealed that pregnancy inhibited the cyclic alterations in the tubes of the sow and the epithelium appeared to remain in the state which was found in the second week after ovulation, when the corpora lutea were full grown (2). Nayak and Zimmerman have presented limited electron microscopic studies of the porcine tubal epithelium during early pregnancy (3) . To the best of our knowledge, no electron microscopic studies of the porcine uterine tube epithelium during late and term pregnancy have been reported.
Ultrastructural Evaluation of Parathyroid Glands and Thyroid C-cells from Cattle Fed Solanum malacoxylon
Authors: Collins W.T. , Capen C.C. , Döbereiner J.
Published: June 2020

Cattle grazing the South American plant Solanum malacoxylon (S. malacoxylon) develop a progressive debilitating disease (“Espichamento”, “Enteque seco“) characterized by the development of hypercalcemia, hyperphosphatemia, and severe soft tissue mineralization (Carrillo and Worker, Revta Investnes agropec., B. Aires, Ser. 4 Patol. anim. 4:9, 1967; Döbereiner et al., Pesq. agropec. bras., Ser. Vet. 6:91, 1971). Recent evidence indicates that dried leaves of S. malacoxylon contain a potent water-soluble substance with biologic activity comparable to that of the hormonally active form of vitamin D (1,25-dihydroxycholecalciferol) that stimulates active intestinal calcium absorption and enhances calciumbinding protein synthesis (Corradino and Wasserman, Nature 252:716, 1974). The objective of this study was to investigate the fine structural changes in thyroid C- and parathyroid chief cells produced by feeding S. malacoxylon to young cattle (118-225 kg body weight) for 1 day (0.4 gm dried leaves/kg/day), 6 days (0.067 gm/kg/day), and 32 days (0.029 gm/kg/day).
The Effect of Vitamin A on the Intermittent Nitrogen Dioxide Gas Exposure in Hamsters
Authors: Kim J.C.S. , Jourden M.G. , Carlisle E.S.
Published: June 2020

Chronic exposure to nitrogen dioxide in rodents has shown that injury reaches a maximum after 24 hours, and a reparative adaptive phase follows (1). Damage occurring in the terminal bronchioles and proximal portions of the alveolar ducts in rats has been extensively studied by both light and electron microscopy (1).

The present study was undertaken to compare the response of lung tissue to intermittent exposure to 10 ppm of nitrogen dioxide gas for 4 hours per week, while the hamsters were on a vitamin A deficient diet. Ultrastructural observations made from lung tissues obtained from non-gas exposed, hypovitaminosis A animals and gas exposed animals fed a regular commercially prepared diet have been compared to elucidate the specific effect of vitamin A on nitrogen dioxide gas exposure. The interaction occurring between vitamin A and nitrogen dioxide gas has not previously been investigated.
Scanning Electron Microscopy and X-Ray Analyses of Dental Tissues from a Hibernator
Authors: Zimny M. L. , Haller A. C.
Published: June 2020

During hibernation the ground squirrel is immobile, body temperature reduced and metabolism depressed. Hibernation has been shown to affect dental tissues varying degrees, although not much work has been done in this area. In limited studies, it has been shown that hibernation results in (1) mobilization of bone minerals; (2) deficient dentinogenesis and degeneration of alveolar bone; (3) presence of calculus and tears in the cementum; and (4) aggrevation of caries and pulpal and apical tooth abscesses. The purpose of this investigation was to study the effects of hibernation on dental tissues employing scanning electron microscopy (SEM) and related x-ray analyses.
Ultrastructural Morphology of two Sensilla Placodea on the Antenna of a Parasitic Wasp
Authors: Barlin Margaret R.
Published: June 2020

Females of the wasp Tetrastichus hagenowii (Hymenoptera: Chalcidoidea) lay their eggs in cockroach egg cases, the young hatch and feed on the cockroach eggs. Prior to egg deposition the parasites follow a complex behavioral sequence, including tapping their antennal tips on the eggcase, thus enabling them to detect various mechanical and chemical properties of the cockroach egg case and determine its suitability for oviposition (unpublished data).

Sensory sensilla occur along the entire length of the female antenna (Fig. 1). Two of the more prominent sensilla were studied by scanning and transmission electron microscopy, these are both sensilla placodea (PI and P2 in Figs. 1 and 2) which are chemoreceptors (1). Numerous hair-like sensilla (H) and a few bulb-like sensilla (B) are also present (Figs. 1 and 2). Sensilla placodea occur frequently on hymenopteran antennae (1), but the occurrence of two types on the same insect has not been reported previously.
Formation of Multinucleated Giant Cells (MGC) in Vitro by Sensitized Macrophages Exposed to Mycobacterium Bovis
Authors: Warfel Alwin H. , Hadden John , Lampen Nina , Pla Dolores , de Harven Etienne
Published: June 2020

Adult rabbits were injected intravenously with heat killed Mycobacterium bovis strain Bacillus Calmette-Guerin (BCG) suspended in oil. As reported previously (1) the rabbits develop a strong infiltration of mononuclear cells which can easily be demonstrated in the lungs 40-50 days post-sensitization. Cells lavaged from these lungs consists of about 82% macrophages, 14% lymphocytes, 3% polymorphonuclear leukocytes and 1% giant cells. Within five to six hours after in vitro cultivation with heat-killed BCG, the macrophages which have already attached to the plastic substrate form clusters apparently by migration. When the mixed population of lavaged cells is cultured for 24 hours many macrophages seem to fuse to form multinucleated giant cells (MGC), whereas cells collected from unsensitized rabbits do not form significant numbers of MGC. A typical MGC containing at least 35 nuclei in the central area of the syncytium is shown in Fig. 1. The mechanism involved in this cell fusion process is not understood.
Electron Microscopy of Extraskeletal Neoplasm Resembling Ewing's Sarcoma
Authors: SUD B. N.
Published: June 2020

Review of 39 cases of sarcomas involving soft tissues, especially of the lower extremity and paravertebral region of children and young adults, disclosed a uniform histologic picture that was indistinguishable from that of Ewing's sarcoma of bone (1). Biopsy of a soft tissue tumor of the right thigh of a ten year old boy was studied by light microscopy and diagnosed as poorly differentiated sarcoma, probably extra skeletal Ewing's sarcoma (2). A portion of the biopsy was processed for electron microscopy to elucidate the ultrastructural pathology.

The specimen revealed a neoplasm, consisting of sheets of viable as well as necrotic tumor cells. The viable cells had a single large rounded, oval or kidney- shaped nucleus with one or more dense nucleoli and chromatin with occasional clumping along the periphery and also in the interior.
Adrenocortical Ultrastructure in Ectopic Acth Syndrome
Authors: Kovacs K. , Horvath E. , Singer W.
Published: June 2020

Secretion of ACTH by non-pituitary neoplasms is recognized with increasing frequency. While the clinical and biochemical changes associated with ectopic ACTH production have been extensively studied recently, relatively little attention was focused on the morphology of the adrenal cortex and, to our knowledge, the fine structure of the adrenocortical cells in cases of ectopic ACTH syndrome has not been described so far. We report here the electron microscopic findings in the adrenal cortex of a 50-year-old man with a pancreatic apudoma. The patient showed the characteristic clinical and biochemical features of ectopic ACTH syndrome and because of extensive hypercorticism, underwent bilateral adrenalectomy.

By light microscopy, the adrenal cortices showed extensive compact cell hyperplasia and lipid depletion. The zona glomerulosa was present in small foci and, except for a few places, fasciculata cells were noted under the fibrous capsule.
Some Problems in the use of Human Hair in Forensics
Authors: West H. L.
Published: June 2020

Several problems arise when two human hairs are compared to determine if both originated from the same person. First, and foremost, is the amount of variation in hair structure of one person; and, in some instances, of a single hair. Variations occur in such externals as cuticle scale dimensions and hair diameter. In multi-racial people there may be different hair “types” on one scalp. One criterion for comparison of two hairs is the presence of congenital hair defects with low incidences of occurrence, such as Monilethrix (1 in 7500), Pili Torti (1 in 50-60,000), and Pili Annulati (1 in 30,000). The presence of the same defect in both hairs of a two-hair random sample indicates a high probability that both hairs are from the same person. The SEM indicates distinct morphologies for these defects. Both Monilethrix and Pili Torti have somewhat regular variations in diameter.
Ultrastructural Characterization of a Murine Squamous Cell Carcinoma (Nettesheim) Induced by 3-Methyl-Cholanthrene
Authors: Liss R.H. , Ifrim I. , Wodinsky I. , Nettesheim P.
Published: June 2020

An invasive squamous cell carcinoma induced in the trachea of inbred mice by repeated intratracheal injection of the polycyclic hydrocarbon, 3- methyl-cholanthrene, is transplantable and exhibits stable morphological characteristics on repeated passage (1). The neoplasm is of current interest as a quantitative assay for testing new lung cancer therapies and for investigating the effects of host factors on the growth of respiratory tract neoplasms (2).

The ultrastructure of the neoplastic tissue implanted subcutaneously in DBA/2 mice was examined 14 and 21 days after inoculation. The tissues were fixed in Karnovsky's fixative (2) and processed for electron microscopy. 60-100 mu sections were obtained with a Porter Blum MT-2B Sorvall microtome, stained with uranyl acetate and lead citrate, and viewed with a Philips 201 electron microscope.
Electron Immunochemical Labeling of Ultrathin Sections of Murine Tumor Viruses and Cell Cultures using the Unlabeled Antibody Enzyme Technique
Authors: Hamilton W. J.
Published: June 2020

The study of RNA tumor viruses has been greatly facilitated by the use of immunochemical tagging methods. In the past these methods have been constrained to antibody conjugates with ferritin or peroxidase. In order to avoid the disadvantages of using conjugated antisera, investigators have applied the unlabeled antibody enzyme method of Sternberger to mammary tumor derived mouse cells prior to embedding for electron microscopy. The current study has successfully applied the Sternberger method to virusproducing cells and purified virus pellets after epoxy-embedding and ultrathin sectioning. The results demonstrate the distinct advantages of this “post-embedding” method for viral antigen localization.

Purified Rauscher leukemia virus (RLV) and mouse mammary tumor virus (MMTV) were pelleted, fixed in buffered 2% paraformaldehyde and washed thoroughly. These were dehydrated in acetone, infiltrated and embedded in Spurr resin according to common procedures. A tumor derived cell line, Mm5mt, producing MMTV was embedded by parallel methods.
Detection and Enumeration of 42 NM Dane Particles by a Thin-Sectioning Procedure.
Authors: Miller M.F. , Ling C M. , Overby L.R. , Rdzok E.J. , Amann C.
Published: June 2020

Hepatitis B surface antigen (HBsAg) consists of three morphological forms identified by negative stain electron microscopy as spherical and rodshaped particles of approximately 22 nm diameter and double-shelled Dane particles of 42 nm diameter (Fig. 1). Dane particles contain DNA and are believed to represent the Hepatitis B virion while the smaller forms of HBsAg are thought to correspond to excess viral lipoprotein antigenically related to the surface of Dane particles. Electron microscopic studies of HBsAg in human blood plasma have always been carried out using negative staining techniques and Dane particles reportedly account for only a very small portion of HBsAg particles found in plasma. In the present study we demonstrate the usefullness of a previously devised thin-section virus particle counting technique (1) for detecting and enumerating Dane particles in either whole or partially purified blood plasma.
Immunoperoxidase Localization of Sindbis Virus Antigen in Infected Vertebrate and Infected Mosquito Cells
Authors: Thomas Virginia L. , Stollar Victor
Published: June 2020

The localization of Sindbis virus (SV) antigen in infected BHK-21 and infected Aedes albopictus (AA) mosquito cells has been studied using the immunoperoxidase technique.

The method of Dougherty et al (1972) as modified and described elsewhere (Thomas & Stollar1974)was used. The cells were seeded and infected on 8 chamber Lab-Tek tissue culture slides (Lab-Tek Division, Miles Labs., Inc.). The immunoperoxidase reaction was also carried out on these slides. Non-specific staining was reduced by exposure of the fixed cells to diluted fetal calf serum before reaction with the anti-SV globulin.

Light microscopy (LM) was used to evaluate the reactions before continuing with electron microscopy (EM). The control (uninfected) cells as seen by LM are not shown due to lack of space. Reaction with the anti-SV globulin in the BHK-21 cells shows localization of the viral antigens predominantly in the perinuclear regions, with small foci of more darkly stained material also visible in the cytoplasm of the infected cells, Fig. 1.
Sem and X-Ray Analysis of Renal and Biliary Calculi
Authors: Narconis R. J. , Johnson G. L.
Published: June 2020

Analysis of the constituents of renal and biliary calculi may be of help in the management of patients with calculous disease. Several methods of analysis are available for identifying these constituents. Most common are chemical methods, optical crystallography, x-ray diffraction, and infrared spectroscopy. The application of a SEM with x-ray analysis capabilities should be considered as an additional alternative.

A scanning electron microscope equipped with an x-ray “mapping” attachment offers an additional dimension in its ability to locate elemental constituents geographically, and thus, provide a clue in determination of possible metabolic etiology in calculus formation. The ability of this method to give an undisturbed view of adjacent layers of elements in their natural state is of advantage in determining the sequence of formation of subsequent layers of chemical constituents.
A Simplified Procedure for Embedding Dilute Suspensions of Biologic Material.
Authors: Pfister R.M. , Hanson J.M. , Smucker R.A.
Published: June 2020

Electron microscopic examination of ultra-thin sections of dilute suspensions of biologic material is difficult, time consuming and unrewarding. Generally, a cell mass from larger cultures compacted in some way or tissue pieces are handled successfully. We have developed a rapid method for embedding and sectioning more dilute particulate materials, such as membrane components harvested from sucrose gradients or dilute cultures.

Bacterial cells, Bacillus cereus and Bacillus subtilis were cultured using a standard growth medium (Tryptone glucose yeast extract broth, 100 ml) for 24 hours at ambient temperature. In this experiment the culture was divided in half at the conclusion of incubation. One half of the mixture (50 ml) was centrifuged to produce a pellet which was immediately frozen in liquid nitrogen. The other half was diluted and utilized during the second part of this experiment.
A Technique for Sequential Examination of in Vitro Macrophage-Tumor Interaction using Lm, Sem and Tem
Authors: Bucana C. , Hobbs B. , Hoyer L. C. , Hanna M. G.
Published: June 2020

A sequential examination of macrophage-tumor cell interaction in vitro, using time-lapse cinematography followed by SEM and TEM of the same cells, is a valuable asset in the interpretation of in vivo and in vitro cell-mediated cytotoxicity assays that are widely used in tumor immunology. Previous reports on sequential examination of biological specimens involved large tissue blocks. This report describes a technique that allows sequential examination of cell - cell interaction using three modes of microscopy.

Guinea pig hepatoma (L-10) cells were plated sparsely on 25mm glass coverslips 24hr before adding guinea pig peritoneal exudate cells (PEC). PEC were allowed to settle for 1 l/2hr; the coverslips were then transferred to a Dvorak-Stotler chamber and examined with a Zeiss photomicroscope III.
A Tem Study of the Crystallization of two Noncrystalline Cu-Zr Alloys
Authors: Freed Robert L.
Published: June 2020

All properties observed in noncrystalline metallic alloys are affected drastically by the irreversible precipitation of crystallites which occurs upon heating these materials beyond a critical crystallization temperature. The purpose of this investigation is to study the transformation to the crystalline state in two noncrystalline alloys, Cu50Zr50 and Cu46Zr54, produced by a piston and anvil splat quenching technique. Differential scanning calorimetry (DSC) was used to monitor the caloric manifestations of crystallization as the material was heated at a constant rate (10°C/min). The crystalline precipitate at intermediate stages of the crystallization process was examined by transmission electron microscopy (TEM) and the related electron diffraction patterns (EDP).
Correlative use of the Sem and other Instrumentation in the Examination of Criminal Evidence.
Authors: Matricardi V. R.
Published: June 2020

The very existence of this symposium on Forensic Applications of Electron Microscopy is testimony to the fact that electron microscopy is being applied to criminal investigations with increasing frequency. The variety of specimens that have been examined with the SEMs (for our purposes we shall assume associated X-ray analysis capability) providing information which could not be obtained by other techniques, is indeed impressive. As adaptable as these instruments are, the data obtained can be augmented by correlation with data obtained from the use of a different instrument. This can, at times, provide more information than that available from each instrument independently. The SEM lends itself easily to this correlation because it is nondestructive, fast, deals with volumes which are smaller than those required by most analytical instruments, and provides topographical analytical information about the surface of the specimen.
Rocking Beam Microarea Diffraction Applied to Metallic thin Films
Authors: Geiss R. H.
Published: June 2020

The theory and practical limitations of micro area scanning transmission electron diffraction (MASTED) will be presented. It has been demonstrated that MASTED patterns of metallic thin films from areas as small as 30 Åin diameter may be obtained with the standard STEM unit available for the Philips 301 TEM. The key to the successful application of MASTED to very small area diffraction is the proper use of the electron optics of the STEM unit. First the objective lens current must be adjusted such that the image of the C2 aperture is quasi-stationary under the action of the rocking beam (obtained with 40-80-160 SEM settings of the P301). Second, the sample must be elevated to coincide with the C2 aperture image and its image also be quasi-stationary. This sample height adjustment must be entirely mechanical after the objective lens current has been fixed in the first step.
Recent Applications in Combined Transmission Electron Microscopy and Microanalysis
Authors: Chescoe Miss D. , Beeston B.E.P.
Published: June 2020

An AEI CORA has recently been used to examine a wide number of applications mainly in the biological field. This instrument with its unique double field condenser/objective lens combines the normal accepted high resolution performance of a transmission electron microscope with X-ray analysis of areas down to a 250°A in diameter.

Environmental pollution is one field in which this technique excels. Although the dangers of handling asbestos are well known and stringent controls operate in industrial use, an individual can be at risk in domestic use, especially when handling some of the home repair kits. Certain spackling compounds were examined by dispersing a small quantity in distilled water and drying down onto a carbon coated grid. As can be seen from the micrograph Fig la many fibres exist, similar in appearance to asbestos.
In Situ SEM Observations of Sintering of Gold Compacts
Authors: Levin E. R. , Auth G. R. , Bube K. R.
Published: June 2020

As part of a study of metallization of preglazed ceramic surfaces for hybrid microcircuits, direct observations of the sintering of gold powders at temperatures in the 800-900°C range have been made in the scanning electron microscope. The changes occurring in the layers at the high temperatures were followed in detail at high magnification. Video tape recordings were made showing the sintering of the gold and the accompanying flow of the glass bonding medium.

The specimens were specially prepared for the SEM studies on thin rectangular ceramic substrates 0.13mmx2mmx8mm. The unsintered gold powder, dispersed in an organic vehicle, was screen-printed in 1 mm-wide stripes along the length of substrate. Prior to sintering, the organic binder was removed by prefiring in air, typically at 400 °C for two minutes (Fig. 1). An intermediate layer of lead-borosilicate glass was used between the substrate and the metal compact to promote adhesion on sintering.