bluuebunny/crossref_metadata_2025 huggingface dataset:
In situ quantitative analysis of GeXSi1-X alloys during growth by reflection EELS
Authors: Nikzad Shouleh , Ahn Channing C. , Atwater Harry A.
Published: June 2020

The universality of reflection high energy electron diffraction (RHEED) as a structural tool during film growth by molecular beam epitaxy (MBE) brings with it the possibility for in situ surface chemical analysis via spectroscopy of the accompanying inelastically scattered electrons. We have modified a serial electron energy loss spectrometer typically used on an electron microscope to work with a 30 keV RHEED-equipped MBE growth chamber in order to determine the composition of GexSi1-x alloys by reflection electron energy loss (REELS) experiments. Similar work done in transmission electron microscopes has emphasized the surface sensitivity of this technique even though these experiments have never been done under ultra-high vacuum conditions. In this work, we are primarily concerned with the accuracy with which core losses can be used to determine composition during MBE growth.
TEM evaluation of graded SixGe1-x heterolayers
Authors: David Theodore N. , Tomozane Mamoru , Liaw Ming
Published: June 2020

There is extensive interest in SiGe for use in heterojunction bipolar transistors. SiGe/Si superlattices are also of interest because of their potential for use in infrared detectors and field-effect transistors. The processing required for these materials is quite compatible with existing silicon technology. However, before SiGe can be used extensively for devices, there is a need to understand and then control the origin and behavior of defects in the materials. The present study was aimed at investigating the structural quality of, and the behavior of defects in, graded SiGe layers grown by chemical vapor deposition (CVD).

The structures investigated in this study consisted of Si1-xGex[x=0.16]/Si1-xGex[x= 0.14, 0.13, 0.12, 0.10, 0.09, 0.07, 0.05, 0.04, 0.005, 0]/epi-Si/substrate heterolayers grown by CVD. The Si1-xGex layers were isochronally grown [t = 0.4 minutes per layer], with gas-flow rates being adjusted to control composition. Cross-section TEM specimens were prepared in the 110 geometry. These were then analyzed using two-beam bright-field, dark-field and weak-beam images. A JEOL JEM 200CX transmission electron microscope was used, operating at 200 kV.
Sintering in Ultrafine Ceramic Particles
Authors: Bonevich John E.
Published: June 2020

Nanocrystalline materials in many respects represent a ‘cutting-edge’ of technology. Ceramists desire ultrafine-grained materials to improve mechanical behavior and exploit their novel properties. However, the sintering behavior of these materials is not well understood. We have endeavored to study the process of sintering in ultrafine alumina particles on an atomic scale. As many properties of nanocrystalline materials exhibit surface-controlled behavior, and alumina surfaces are highly reactive, a concerted effort was made to minimize contamination by conducting the experiments in ultra-high vacuum (UHV).
Large-Scale Interlaboratory Study of the Accuracy of Asbestos Analysis by TEM
Authors: Turner S. , Doorn S.S. , Phelps J.M. , Windsor E.S. , Steel E.B. , Beard M.E.
Published: June 2020

The National Institute of Standards and Technology (NIST) has been mandated by Congress to accredit and to test the proficiency of laboratories involved in the analysis of asbestos on filters by TEM. The laboratories are specifically accredited as proficient in the determination of the concentration of asbestos in air following abatement (or removal) of asbestos from school buildings using analytical procedures developed by the Environmental Protection Agency (EPA). Related to the accreditation program, NIST has conducted two interlaboratory studies of the accuracy of analysis by TEM. The first study involved comparison of analyses by 15 laboratories. This work describes a large-scale study of the accuracy of analysis of asbestos on filters by 113 laboratories.
Energy-dispersive x-ray detectors for analytical electron microscopy
Authors: Thomas L. E.
Published: June 2020

Continuing evolution of energy-dispersive x-ray spectrometer (EDS) systems has greatly advanced x-ray detector performance in analytical electron microscopes. The latest detectors offer improved energy resolution, count rate performance, geometrical collection efficiency, durability, and efficiency for light and heavy elements. Innovative detector designs for transmission and scanning transmission electron microscopes (TEM/STEMs) include such features as liquid-nitrogen-free operation, in situ de-icing of the detector crystal, user cleanable windows, demountable windows, ultrahigh vacuum compatibility (including adaptations to allow microscope bakeouts without removing the detector), beam damage protection, and microscope interfaces with optimized collection geometries. Divergent design philosophies have produced a variety of systems with specialized features, and users may face hard choices in selecting the best detector for the job. The aim of this paper is to review the current state of EDS detector development and the importance of the performance improvements to TEM/STEM users.
The Large Depth of Focus (LDF) Mode in 3-Stage Lens System
Authors: Matsuya M. , Saito M. , Nielsen C. H. , Nakagawa S.
Published: June 2020

The Large Depth of Focus (hereinafter abbreviated to LDF) mode has been developed. The depth of focus in the LDF mode has been made 3 to 5 times larger than that in a conventional probe forming system by changing the positions of imaging points in the 3-stage lens system. The LDF mode has been applied successfully to observing the specimen with a large height difference (2 mm) without defocus and to analyzing it by EDS.
Diffraction and Imaging from all Perspectives: Unlimited Specimen Tilting in the High-Voltage Electron Microscope
Authors: Turner J. N. , Barnard D. P. , McCauley P. , Dorset D. L.
Published: June 2020

Electron diffraction patterns and images of three-dimensional (3D) objects are limited by the range of specimen tilt angles. This range is commonly limited by the specimen holder, but for angles >60°, the slab-like nature of most specimens is itself a fundamental limitation. At 60° the beam path is twice the thickness of the untilted specimen, at 70° it is three times, and at 90° it is infinite. For angles > ± 60°, the information is severely degraded or unattainable This causes serious problems for electron crystallography, and for electron microscopic tomography. For the former, it can result in series termination errors in the computation of electrostatic potential maps from the structure factor amplitudes, and for the latter, it results in reconstructions with anisotropic resolution. To overcome these limitations, we are developing specimen stages and preparation procedures based on a “cylindrical” geometry i.e. all dimensions transverse to the tilt axis are a few micrometers or less.
BF STEM Cs measurement using power spectrum analysis
Authors: Wong Kaikee , Xu Peirong , Loane Russell , Kirkland Earl , Silcox John
Published: June 2020

The coefficient of spherical aberration, Cs, is important in evaluating the performance of an electron microscope. Power spectrum analysis of amorphous carbon images is commonly used to determine Cs in conventional TEM. This method has been thought to be difficult to apply to STEM because of the conflicting demands that the BF detector be small and the noise level be low. In this paper we report that by using a small detector and a computer image acquisition system, power spectrum analysis can be applied to BF STEM to measure Cs and defocus accurately.
Advantages of Koehler illumination for selected area diffraction
Authors: Benner G. , Bihr J. , Weimer E.
Published: June 2020

The advantages of Koehler illumination for imaging are well known. This new mode of illumination in the Transmission Electron Microscope (TEM), however, provides advantageous results for all modes of operation of a TEM, in particular for Selected Area (SA) diffraction.

In a conventional TEM, the last condenser lens is strongly excited (coherent illumination) to obtain selected area diffraction. The size of the diffraction spots is determined by the demagnified image of the electron source (cross-over) in the back focal plane of the objective lens. Since a large area of the specimen is illuminated, the diffracting area must be limited in the intermediate image plane by the selected area aperture (Fig. 1a).

Due to the spherical aberration of the objective lens, the higher orders of the diffraction pattern of the axial points are eliminated by the selected area apertures and are thus lost in the photograph of the diffraction pattern (dashed rays in Fig. 2).
High-resolution electron microscopy on SSZ-26 zeolite materials
Authors: Pan M. , Crozier P.A. , Chan I.Y. , Zones S.I.
Published: June 2020

Zeolites constitute an important class of catalyst materials in the petrochemical industry. Zeolites are aluminosilicates with their framework structures made up of SiO4 (or AlO4) tetrahedra. The catalytic properties such as selectivity and activity are closely related to the structure sensitive properties of zeolites, e.g. shape selectivity, diffusivity, etc. Understanding these properties requires detailed structure characterization of the zeolites. High resolution electron microscopy (HREM) has been successfully applied to solve some zeolite structures when combined with experimental data from other techniques, e.g. absorption experiment. The connectivities of n-member rings in the zeolite frameworks can be directly deduced from the corresponding HREM images. However, radiation damage to the zeolite framework structures by the electron beam necessitates the use of low dose imaging techniques.
Orientation of poly(3-alkylthiophene) on polyethylene crystals
Authors: Ihn K.J. , Moulton J. , Smith P.
Published: June 2020

Poly(3-alkylthiophene)s (P3ATs) are conductive polymers soluble in many organic solvents. The number of carbon atoms (n) in the linear side chain in P3ATs used in this study was 6, 8, and 12. We concentrate on the result of P3HT (n=6), since similar results were obtained for the other two cases. In this paper we will report the molecular packing in P3HT whisker, and also the morphology and orientation of P3HT epitaxial growth on polyethylene (PE) crystals.

P3HT whiskers were grown from a dilute solution of cyclohexanone while cooling the solution to room temperature. The color of the solution changed to red from yellow as the whiskers were formed. P3HT whiskers were also grown in cyclohexanone solution on PE single crystals mounted on a Cu grid supported by carbon film. Ultra-high molecular weight (UHMW) PE (Mw=4x106) gel film was uniaxially stretched (draw ratio=100). The drawn gel film was dipped into a xylene solution of P3HT at room temperature in order to crystallize the P3HT molecules onto the PE crystal. The samples were examined by a transmission electron microscope (TEM) at 80 kV.
(001) grain boundaries in Ag-clad Bi2Sr2Ca1Cu2O8+y (BSCCO) tapes
Authors: Feng Y.
Published: June 2020

Recently, Ag-clad tapes of Bi-cuprate superconductors have shown great promise for application as conductors in very high magnetic fields at temperature 4-20 K. High critical current densities (Jc) with weak field dependence indicate that the powder-in-tube process can drastically reduce the effect of grain boundary weak links at 4-20 K. It is thus of great interest to study the grain boundaries in the Ag-clad BSCCO tapes to understand their effect on the Jc.

BSCCO Ag-clad wires with 2:2:1:2 starting composition were drawn and rolled to rectangular tapes (0.1 x 3 mm) with BSCCO core thickness of 45μm. The sample was heated at 920°C for 15 minutes, cooled to 840°C at 10°C/h, then annealed at 840°C for 70 h. The measured Jc values exceed 2x104 A/cm2 (5T, 4.2K) and do not exhibit obvious weak link behaviour. In order to investigate the (001) grain boundaries, samples were made by bonding several tapes together along their broad face. Thin longitudinal slices were cut and then ion milled at 4.5 kV in liquid nitrogen. TEM was carried out by using a JEOL 200CX-II at 200 kV.
A TEM study of the effect of silver additions on residual superconductivity in shock-loaded Y-Ba-Cu-O
Authors: Birudavolu R. , Advani A.H. , Murr L.E.
Published: June 2020

Although it has been demonstrated that metal additions to superconducting oxides can have a dramatic effect on superconductivity (as evidenced by variations in the resistancetemperature (R-T) signature), it is unclear where the metal additions go in the structure and what mechanism or mechanisms control the observed variations in superconductivity.

Recent observations of explosively fabricated bulk YBa2Cu3O7 superconductors and sintered, shock-loaded YBa2Cu3O7 have indicated systematic degradation in the R-T signatures following shock-wave loading which increases with increasing peak shock pressure. However, silver additions to the Y-Ba-Cu-0 are observed to decrease this degradation. As illustrated in Fig. 1, the normal-state resistance becomes more metallic and the superconducting transition width decreases with increasing silver additions to sintered Y-Ba-Cu-O following shock loading at 3GPa peak pressure in a gas gun.
TEM specimen preparation of individual SiC/C composite (SCS-6) fibers
Authors: Alani R. , Swann P.R.
Published: June 2020

SiC/C based fibers (SCS) have exciting possibilities as reinforcements in advanced metal and ceramic matrix composite materials and there has been a growing interest in preparing specimens of these fibers for TEM studies. Unfortunately, the task of preparing very thin cross section of entire fibers is difficult because the constituent materials making up the fibers have widely different ion milling rates i.e. a carbon core surrounded by a SiC layer coated internally and externally with carbon. In this article, a rapid and reliable technique for preparing TEM specimen of the SCS-6 SiC fiber (manufactured by Textron) is described and together with the results of CTEM, HREM and PEELS studies. The technique is based on a general method of TEM specimen preparation of small objects, e.g. fibers and powder, reported elsewhere.
Using cross sections of binary alloy thin films for TEM study of chemical reactions
Authors: Dufner D.C.
Published: June 2020

As previously applied in the study of the Au-Sn system, a method of preparing thin-film binary metal couples for high-resolution TEM was effective in studying chemical reactions. The two-film method introduced by Shiojiri formed a solidsolid interface through which interdiffusion of the metals can take place and allowed for compositional and structural changes to be observed in the TEM. Figure 1 shows a cross-section schematic of a Pt-Sn couple used in this study. However, if one were to observe this configuration with the electron beam normal to the film surface, the actual reaction interface could not be observed directly. Therefore, the use of epoxy cross-sections of these two-film couples was proposed to allow direct observations of such interfaces.
Techniques in preparing TEM specimens of mechanical alloyed fine powders
Authors: Chiou W. A. , Ramanathan R. , Stux A. , Lin Y. , Meshii M.
Published: June 2020

The discovery of solid state processing of nanocrystalline and amorphous metals is considered to be a formation of a vital technology because of the potential in applications of these materials. Among the processes which are suitable tailoring advanced materials, mechanical alloying techniques are of special interest since they offer the most flexibility in mixing the constituent elements. To understand structural transformation from crystalline to amorphous states during mechanical alloying, the microstructural information from TEM is essential. This paper presents three different techniques used in preparing mechanically alloyed powder specimens for TEM study.

Samples of commercially produced fine-grained (325 mesh) Cu (99.3%) and Zr (99%) powders were weighed to an atomic ratio of 1:1 as starting materials. These powders were mixed together in a steel vial and ball-milled in a SPEX mixer/mill machine. Samples were taken out after 11 hours of mixing when X-ray patterns showed that some amorphization had occurred. To examine the microstructure of these fine powders, three techniques were employed: (1) the suspension of powder particles on holey carbon film, (2) the epoxy-embedding for thin-sectioning technique, and (3) the microtome technique.
Formation of nanoclusters on polymer thin films
Authors: Burns Janet L. , Echert Charles J. , Spontak Richard J.
Published: June 2020

Several different techniques are currently employed for producing thin polymeric films for study in transmission electron microscopy (TEM), but the two most common routes are (cryo) ultramicrotomy and thin-film casting. Sections obtained from embedded samples or at low temperatures are valuable in correlating observed microstructure with bulk physical properties, without concern over non-equilibrium issues. However, thin-film casting is often equally useful, especially if there exists an interest in structure morphology at surfaces, which may help to elucidate surface (e.g., adhesive) properties of the material. In either case, resulting thin films can be further processed on TEM grids prior to imaging. Normally this additional step requires subjecting a film to an elevated temperature (T) for a predetermined period of time (t). Unlike most metals which are annealed at relatively high temperatures (>500° C) and most biological systems which are heated to temperatures typically less than 100° C, many polymeric materials are often subjected to temperatures between 100° and 400° C.
Localization of Acetylcholine Receptors with Peroxidase-Labeled α-Bungarotoxin
Authors: Lentz Thomas L. , Chester Janice , Rosenthal Jean
Published: June 2020

A procedure has been developed for the cytochemical localization of acetylcholine (ACh) receptors by means of the snake neurotoxin α-bungarotoxin (α-Btx) labeled directly with horseradish peroxidase (HRP). Conjugation of HRP to α-Btx was carried out according to the method of Nakane and Kawaoi (1). A fraction of the conjugate with a MW of ∿48,000 was separated from free peroxidase and heavier MW fractions by column chromatography. This fraction corresponds to a conjugate in which one molecule of HRP is coupled to one of α-Btx. It was found to retain physiological activity since it produced a postsynaptic blockade at frog sartorius neuromuscular junction similar to that obtained with native α-Btx. For localization of receptors, mouse diaphragm, frog sartorius, or newt limb muscles were incubated in the conjugate for from one half to two hours, fixed in glutaraldehyde, reacted with H2O2 and diaminobenzidine for peroxidase activity, fixed in osmium tetroxide, and processed for electron microscopy.
Direct Observation of Membrane Motion and Fluidity by Electron Microscopy
Authors: Hui S. W.
Published: June 2020

Apart from a few studies on chemical reactions (1), the electron microscope is seldomly used for kinetic observations. The major difficulty in applying electron optical techniques to kinetic measurement had been the requirement that the specimen be placed in a vacuum. The recent development of environmental stages (2) has partially overcome this problem. The application of this technique to biological research will enable biological reactions to be observed in detail under a physiological environment.

For studies of membrane motions, various molar mixtures of cholesterol, dipalmitoyl phosphatidylcholine and natural phosphatidylserine (extracted from bovine brain) were used. Unsupported bilayers were formed on fine mesh grids by dipping them through mono-molecular layers in a Langmuir trough (3).
The Regulation of Silica Incorporation Into the Stinging Cell Wall of Urtica Pilulifera
Authors: Sowers Arthur E. , Laurence Thurston E.
Published: June 2020

Silicification in biological systems results from the polymerization of silicic acid (Si(OH)4) monomers (1). It has been reported (2) that silification takes place in a very characteristic way in the stinging cell wall(Fig. 1, arrow) of the “Stinging Nettle” (Urtica pilulifera). The cell wall is composed of an organic and an inorganic (silica) component, and the latter occurs in two phases: matrix and particulate (Figs. 2, 3, and 4).

It can be postulated that macromolecular assembly in biological systems involves proteins with both catalytic and regulatory sites which probably have different substrate specificities and sensitivities. Germanic acid and several silanes with organic functional groups substituted in place of one or more of the hydroxyl groups in silicic acid are easily prepared from commercially available compounds. Such compounds make ideal analogues by which the regulation of this unique silicification can be studied.
The Fine Structure of Phialophora Mutabilis Grown on Various Media
Authors: Pardo Matias , Keller Betty , Pouchet Gail , Slifkin Malcolm
Published: June 2020

Culturally and morphologically, P. mutabilis manifest wide variation in regard to pigmentation and colonial and microscopic appearance(1) . A composite of all the cultural characteristics of this fungus manifested only when a variety of media was employed for cultivation. Colonies grown on Sabouraud ' s dextrose agar, malt extract and Wort agar generally contained a central pigmented mycelial mat and a yeast-like peripheral zone. The colonies were completely yeast-like on corn meal agar. Microscopic examination from slide cultures on different media revealed conidia, chlamydospores and rare phialides.

This is the first ultrastructural analysis of P. mutabilis. Culture from Sabouraud's dextrose agar were examined first. The outer surface of the hyphal cell walls is electron dense with a fibrillar network.
Ultrastructure and Morphology of the Neurospora Crassa Cell Wall Mutants, Slime And Slime X, Using Tem and Sem
Authors: Howard Karen S. , Braymer H. D. , Socolofsky M. D. , Milligan S. A.
Published: June 2020

The recently isolated cell wall mutant slime X of Neurospora crassa was prepared for ultrastructural and morphological comparison with the cell wall mutant slime. The purpose of this article is to discuss the methods of preparation for TEM and SEM observations, as well as to make a preliminary comparison of the two mutants.

TEM: Cells of the slime mutant were prepared for thin sectioning by the method of Bigger, et al. Slime X cells were prepared in the same manner with the following two exceptions: the cells were embedded in 3% agar prior to fixation and the buffered solutions contained 5% sucrose throughout the procedure.

SEM: Two methods were used to prepare mutant and wild type Neurospora for the SEM. First, single colonies of mutant cells and small areas of wild type hyphae were cut from solid media and fixed with OSO4 vapors similar to the procedure used by Harris, et al. with one alteration. The cell-containing agar blocks were dehydrated by immersion in 2,2-dimethoxypropane (DMP).
Biogenesis of Catalase-Positive Rods in Excretory Duct Cells of Salivary Glands
Authors: Romanovicz Dwight K. , Hanker Jacob S.
Published: June 2020

The presence of catalase-positive rods (Fig. 1) of different dimensions, which frequently have a crystalline appearance by light microscopy, has been reported. They seem to be related to peroxisomes which were characterized morphologically and cytochemically in parotid and other exocrine glands of the rat by Hand in 1973. Our light microscopic studies of these spherical microbodies and rods of different sizes, stained by virtue of the peroxidatic activity of their catalase, indicate that they are almost entirely confined to the cells of the striated and execretory ducts of the submandibular gland in the mouse. The rods were usually noted only in the proximity of the ductal microbodies. The latter frequently showed a tendency to appear in linear close array, or even to be contiguous (Fig. 2). This suggested that the rods could be formed by the fusion of microbodies.
An Attempt at the Cytochemical Localization of Citrate Synthase in Rat Heart Muscle
Authors: Matlib M. A. , Shannon W. A. , Srere P. A.
Published: June 2020

Most of the Krebs cycle enzymes are believed to exist in ‘soluble’ form in the mitochondrial matrix except succinate dehydrogenase which is a part of the inner membrane (1). Citrate synthase, one of the Krebs cycle enzymes, is present in rat liver, kidney and heart mitochondria proportional to the amount of the inner membrane area rather than the matrix volume (2). Recent studies on model systems support the idea that the ‘soluble’ Krebs cycle enzymes are probably localized on the inner surface (matrix side) of the inner membrane (3-5). Localization of these enzymes in mitochondria by cytochemical or immunocytochemical methods would be crucial to determine the validity of the above hypothesis. The present study describes cytochemical localization of citrate synthase in rat heart muscle.
Effects of Field Stimulation on Nerve Terminals in Human Blood Vessels.
Authors: Thureson-Klein Åsa , Stjärne Lennart , Brundin Jan
Published: June 2020

Noradrenaline and dopamine ß-hydroxylase normally appear to be released from the nerve terminal by exocytosis and data from several laboratories indicate that, during severe stress, a close correlation exists between the level of these substances in the plasma and sympathetic activity. Ultrastructural evidence for exocytosis at the noradrenergic terminal in humans is lacking and it is not known if the large vesicle (LV) or small vesicle (SV) type, or both, are involved in the release process. The present study was performed to find morphological evidence of exocytosis.

Portions of omental arteries and veins were obtained from patients undergoing abdominal surgery using routine general anesthesia. Control vessels were placed in fixative within 10-30 sec after excision, or they were treated similarly to experimental vessels except that field stimulation was omitted prior to fixation.
Endocytosis and Digestion in Entamoeba Histolytica.
Authors: Lushbaugh W.B. , Kairalla A.B. , Pittman J.C. , Pittman F.E.
Published: June 2020

Internalization of particulates and liquids (endocytosis) and the assymilation of ingested foodstuffs have been well documented for several free living amebae (Pelomyxa and Acanthamoeba). Less is known about these processes in the human parasitic ameba, Entamoeba histolytica.

Axenically cultivated trophozoites of E. histolytica, strain HM-1:IMSS, were studied by transmission electron microscopy of thin sections and freeze-etch replicas prepared from cells incubated (5 min to 3 hr) with latex beads, erythrocytes or bacteria.

Tubular channels formed by plasmalemma invagination appeared to be associated with pinocytosis (Fig. 1). These were similar to the pinocytotic channels described by Chapman-Andreson and Nilsson for Pelomyxa.
Sem of an Abnormal Human Abortus and its Placenta
Authors: Watson John H. L. , Swedo John L. , Drukker Bruce H.
Published: June 2020

Because of the important relationship known to exist between abnormal placenta and the occurrence of spontaneous abortion, SEM is being applied to a study of the surface structure of placenta and embryo in such cases, one of which is reported here. The stunted and disorganized remains of a human embryo were obtained from spontaneous abortion at 78 days following the conception date. From text book comparisons with micrographs of its head (Fig. 1) the specimen appeared to have developed incompletely to about the 4th week. It was processed completely within the amniotic sac (1), except for sputter-coating with Au-Pd which was done after the amnion was opened. The specimen, lying in the sac and attached to the placenta was somewhat longer than 3mm. In the lateral view of the head (Fig. 1) the fore brain (B), the mandibular arch (M) and the possible depression of the auditory pit (A) were the only facial features identifiable.
Scanning Electron Microscopy of Blaberus Giganteus (L.) Maxillary Palp Sensilla
Authors: Dailey P.
Published: June 2020

The maxillary palps of B. giganteus are located on the maxillae which lie between the labrum and labium. They are modified appendages used in feeding. Each appendage bears 5 segments, the most distal of which contains the palp organ or sensory pad (Fig. 1). The maxillary palps were fixed in 2.5% glutaraldehyde in 0.05 M sodium cacodylate buffer (pH 7.1) containing .15 M sucrose and post-fixed in 1% osmium tetroxide in buffer. This was followed by dehydration and critical point drying. Cryofractography was performed on some of the palp organs prior to drying (1).

The sensory pad is composed of an exocuticular membrane upon which lie numerous sensilla basiconica in an elliptical pattern on the ventral surface. The membrane enables the sensory pad to expand and, in living specimens it appears dome-like due to the pressure exerted on it by the hemolymph.
Comparison of Several Sem Imaging Modes in Studying Intracellular Particulates in the Lung
Authors: Abraham J. L. , Miyai K.
Published: June 2020

The scanning electron microscope (SEM) offers several signal modes, each of which may contain unique information about the specimen. In this paper we demonstrate and compare the merits of the familiar secondary electron (SE) mode, the backscattered electron (BSE) mode, and x-ray distribution mapping.

Lungs of hamsters treated intratracheally with the radiographic contrast medium tantalum suspended in carboxymethyl cellulose were fixed with intratracheal buffered 2% glutaraldehyde. Blocks were razor cut to a few mm, dehydrated and critical point dried. The dried blocks were mounted on aluminum SEM studs and coated with carbon,, followed in some instances by gold/palladium (60/40). Examination at 20 kv and 45° specimen tilt was done in an Etec SEM with a solid state BSE detector and a Cambridge S4 SEM with an ORTEC energy dispersive x-ray analysis system.
Alpha-1-Antitrypsin Deficiency: An Ultrastructural Case Study
Authors: Simons P. K.
Published: June 2020

Alpha-1-antitrypsin is a broad spectrum protease inhibitor produced by the liver. It accounts for 90% of the serum alpha-1 globulins. Normal serum levels of alpha-1-antitrypsin are 200-400 mg/100ml. The protease inhibitor serum level shows a distinct rise in response to tissue injury. Activity with chymotrypsin, elastase, hyaluronidase, skin collagenase, plasmin, and thrombin has been reported. It may have a role in providing protection to normal tissues by neutralizing enzymes released from dying cells as a result of injury or inflammation.

Deficiency of alpha-1-antitrypsin is inherited as an autosomal recessive. Phenotype is determined by electrophoretic mobility in Starch-Gel electrophoresis. Normal individuals show M bands (for medium speed) and the homozygous dominant phenotype is designated PiMM. Two other electrophoretic migratory bands are observable in different phenotypes of this protease inhibitor: the S band (slower mobility than the M band) and the Z band (slowest).
Unusual Inclusions in Neutrophils of two Human Renal Allografts
Authors: Valenzuela R. , Deodhar S.D. , Osborne D.G. , Braun W.E. , Banowsky L.H.W.
Published: June 2020

During a retrospective light and electron microscopy study of 158 human renal allograft biopsies, we observed, in two cases, unusual inclusions in the neutrophils trapped in glomeruli and paratubular capillaries. For electron microscopy, the specimens were fixed in glutaraldehyde, post-fixed in osmium tetroxide and embedded in Epon. Thin sections were stained with uranyl acetate and lead citrate. Eighty-six of the electron microscopically examined biopsies did not contain any neutrophils for evaluation, and only 10 biopsies showed four or more neutrophils.

The two patients, A age 35 and B age 42, had received a cadaver donor renal allograft because of chronic renal failure secondary to hereditary nephritis and nephrosclerosis respectively. Neither patient was affected by any known primary blood disorder.
Intracisternal Membranes in Tumor Cells
Authors: Chew E.C. , Sun C.N. , White H.J.
Published: June 2020

To our knowledge, membranous structures have not been heretofore reported in the cisternae of granular endoplasmic reticulum. Such unusual structures were seen in the course of study of Chang's hepatoma cells (1).

The tumor cells from Chang's hepatoma were kindly given us by Professor J.P. Chang and carried in our laboratory by subcutaneous transplantations. Tissue fragments were fixed in 4% phosphate buffered glutarladehyde and post-fixed in 1% osmium tetroxide. Routine procedures were followed for dehydration and embedding in Epon 812. Sections were stained with uranyl acetate and lead citrate.

As cited above, cisternal membranous structures were observed (Fig. 1), and similar structures were seen in the perinuclear cisternae (Figs. 2&3). The latter were devoid of ribosomes. In some instances, these membranes were not connected to the original membranes of the granular endoplasmic reticulum, while in many cases they were fused with the pre-existing membranes forming two separate cisternae (Figs. 1,2&3). These structures were also seen in hepatoma cells undergoing mitosis (Fig. 4).
Type C Virus Associated With a Gibbon APE Lymphocytic Leukemia
Authors: Walling M. J. , Aoki T. , Gallagher R. E. , Gallo R. C.
Published: June 2020

The occurrence in a gibbon ape of a lymphosarcoma and a myelogenous leukemia accompanied by the presence of a type C virus was reported by Kawakami et al. in 1972 (1). The present study was undertaken on another gibbon ape which spontaneously developed lymphosarcoma with lymphocytic leukemia. Fresh tissue was obtained by autopsy from the animal, a 7½ year old (young adult) male. A plasma sample was also taken prior to death. The whole tissue was fixed in 2.5% glutaraldehyde (buffered), postfixed in 0s04(l%) and embedded in Epon. Staining was carried out with uranyl acetate and lead citrate. The plasma was pelleted by ultracentrifugation and processed for negative stain using phosphotungstic acid. Thick sections of the Epon embedded material were taken to determine the exact area studied.
Effects of Intracarctid Injections of Reserpine on Cerebral Tissue
Authors: Dodson R. F. , Chu L. W-F. , Tagashira Y.
Published: June 2020

Therapeutic effectiveness of the catecholamine depleting agent, reserpine, has been reported in one type of cerebrovascular injury, the cryogenic lesion, to result in reduced edematous involvement (1). Other assessments of the effects of reserpine on cerebral oxidative phosphorylation and arterial blood pressure have been carried out. To our knowledge, however, no previous ultra structural studies have been done following reserpine treatment either in normal cerebral tissue or in ischemic tissue . The importance of determining the effect of reserpine on normal cerebral tissue ultra structure is emphasized by the reported observations of ultra structural changes in rat pituitary (2), mouse abdominal sympathetic paraganglia (3), and the subclavian glomera of the rabbit (4) following reserpine injection.
Air Pollution-Induced Pulmonary Lesions using Sequential Examination by Sem, Lm, and Tem
Authors: Hyde D. , Tyler W. , Dungworth D. , Orthoefer J.
Published: June 2020

Previous exposures of animals to air pollutants have mostly been for short terms and at levels considerably greater than ambient concentrations (1). This report, however, relates to a study in which beagle dogs were exposed for 68 months to a variety of air pollutants at high ambient levels. After a 33-36 month post-exposure period, the lungs from 71 beagle dogs were fixed via the airways with cacodylate-buffered glutaraldehyde-formaldehyde. Lungs of 6 dogs were examined from all but one of 8 experimental groups. Various levels of bronchi and bronchioles were identified under a dissecting microscope and bisected with razor blades. One-half of each airway was prepared for scanning electron microscopy (SEM) after dehydration by critical point drying with CO2and coating with gold-palladium.
Ultrastructural Effects of Acute Kepone Treatment in Rats
Authors: Klein Richard L. , Thureson-Klein Åsa K. , Mehendale Harihara M.
Published: June 2020

KeponeR (decachlorooctahydro-1,3,4-metheno-2H-cyclobuta[cd]pentalen-2-one) is an insecticide effective against ants and roaches. It can cause severe toxicity in fishes, birds, rodents and man. Prominent effects include hepatic lipid deposition and hypertrophy, impairment of reproductive capacity and neurological disorders. Mitochondrial oligomycin-sensitive Mg2+-ATPase is also inhibited. The present study is a preliminary investigation of tissue ultrastructural changes accompanying physiological signs of acute toxicity, which after two days treatment include: pronounced hypersensitivity and tremor, various degrees of anorexia and adipsia, and decreased weight gain.

Three different series of adult male Sprague-Dawley rats (Charles River or CD-I) were treated by intubation with Kepone in corn oil at a dose of 50 mg per kg for 3 successive days or at 200 ppm in food for 8 days. After ether anesthesia, rats were immediately perfused via a cannula in the left ventricle with 4% p-formaldehyde and 0.5% glutaraldehyde in Millonig's phosphate buffer at pH 7.2 for 20-30 min at 22°C.
Electron Microscopic Studies of Labeled Nucleic Acids
Authors: Cole M. D. , Rose S. D. , Wiggins J. W. , Beer M.
Published: June 2020

Quantitative conversion of cytosine nucleotides to N4-furfuryloxy derivatives followed by reaction with osmium tetroxide plus bipyridine yields an electrondense stain suitable for visualization in the electron microscope. Chemical analysis shows that two osmium atoms become attached to each furan-modified cytosine nucleotide. Osmium tetroxide also reacts with thymine and uracil nucleotides, resulting in the attachment of one osmium atom each. Therefore the treatment of cytosine-modified nucleic acids with osmium tetroxide should allow recognition of cytosine and thymine nucleotides.

Nucleic acids labeled with osmium by the above reactions have been viewed in a high resolution STEM. The signal used to form the image is the ratio of the elastically scattered intensity to the unscattered and ineiastically scattered intensity. The dosage that yields a signal to noise ratio sufficient for focussing is >104electrons/ Å2.
A Simple Device for Tissue Dehydration: Application of Concentration Gradient Generator
Authors: Goldfarb D. , Miyai K. , Hegenauer J.
Published: June 2020

We describe a simple device for dehydrating tissue for electron microscopy. Devices of the same general configuration are widely applied in chromatographic separation and density gradient centrifugation, which requires the generation of simple concentration gradients in a continuous rather than stepwise fashion. The application of this technique to tissue dehydration saves time and expense compared to manual and commercially available mechanical methods.

The device consists of two parts: I. a gradient generator, and II. a tissue tray (Fig. 1). The upper part of the device consists of the concentration gradient generator, composed of reservoirs A, B, C and Delrin plate D. Torus A and cylinder B are connected by a channel E. Stopcock F permits independent filling of the reservoirs.
Histochemical Staining of Semi-Thin Sections after Removal of Epoxy Resins
Authors: Lloyd Bolivar J. , Fultz Doris G. , Armstrong Caroline E. V. , Julio Martinez A.
Published: June 2020

Casanova (19 74) has reported that the method of Mayor (19 61) is the best f or removal of epoxy resins. In her method, sodium methylate was made using sodium metal. We have modified this using sodium methylate powder.

1. 5 gm of sodium methylate was dissolved in a beaker in 2 5 ml of methyl alcohol. As it dissolves the beaker becomes warm. When completely dissolved, 2 5 ml of benzene is added with stirring. If rings appear at the interface, mo re alcohol should be added until the rings disappear.
Effects of Vinblastine on the Structure and Function of the Rat Exorbital Lacrimal Gland
Authors: Kelly Robert B.
Published: June 2020

Antimicrotubular agents such as vinblastine and colchicine have been used to assess the role of cytoplasmic microtubules in secretory processes (for review, see 1). The purpose of this study was to determine the effects of vinblastine on the structure and function of resting and pilocarpine- stimulated acinar cells of the rat exorbital lacrimal gland.

Rats were divided into four groups: (a) untreated control; (b) vinblastine (4 mg/kg) treatment for 1 to 24 hours; (c) pilocarpine (20 mg/kg) treatment for 1 hour; and (d) vinblastine treatment for 1 hour, followed by pilocarpine treatment for 1 hour. Both drugs were administered via single intraperitoneal injections. The glands were fixed by perfusion and processed for electron microscopy.
High Voltage Electron Microscopy of Defects in Lithium Ferrite Spinel
Authors: Mishra R. K.
Published: June 2020

Ferrimagnetic oxide spinels are an important class of modern technological ceramic materials. These have,long been recognised as being predominantly ionic in nature. Hornstra's crystallographic study of planar and line defects in spinel structure shows that dislocations of Burgers vector 1/2<110> can dissociate into two partials 1/2<110> = 1/4<110> + 1/4<110> bounding a cation stacking fault on ﹛1ll﹜ glide planes. These partials, in turn, can dissociate into quarter partials of Burgers vector 1/12<112> on ﹛1ll﹜ planes, reducing strain energy and at the same time preserving electroneutrality through a synchroshear mechanism. The current paper describes experimental studies on the nature of the glide dislocations and their dissociation in lithium ferrite (inverse spinel) using high voltage transmission electron microscopy. High order bright field electron micrographs taken in the HVEM together with the computed image profiles implementing multibeam dynamical theory are used to determine the fault plane and estimate the stacking fault energy.
Forensic Analysis of Disintegrated Grinding Wheels using the Sem and X-Ray Microanalysis
Authors: Brown John L.
Published: June 2020

Grinding is a microscopic chipping process for removing material from metal or other hard surfaces. This is commonly accomplished by a rotating wheel consisting of abrasive grains bonded into place with a resin or ceramic material. Aluminum oxide and silicon carbide are the usual abrasives. The most frequently used bond is a vitrified composition of feldspars and clays fired in a ceramic process along with a desired mixture of abrasives. This type of wheel is very hard and easily subject to damage and is normally used in a stationary grinding position. For portable hand-held grinding a resin bonded wheel is used. Resinoid wheels have a more porous structure than vitreous wheels and can be used at high speeds for cool cutting. Frequently fabric reinforcement is used within the structure of the wheel, and it may be operated at higher RPM than other types of wheels.
The X-Ray Multichannel Analyzer
Authors: Schamber F. H.
Published: June 2020

The multichannel analyzer (MCA) is a necessary instrument for the effective utilization of a solid-state X-ray detector. The designation MCA is commonly applied to any instrument which can accumulate a digitized spectrum within an internal storage memory; each individual storage “channel” of this memory represents the amplitude of a discrete data point of an acquired spectrum. The functions of a multichannel analyzer can be broken down into 3 major divisions:

1. data acquisition

2. display and readout

3. data manipulation and reduction

The most important acquisition mode for X-ray spectroscopy is known as Pulse Height Analysis (PHA). In this analysis mode the fast, random pulses generated by the front-end detector electronics (detector, preamplifier, amplifier) are sorted by amplitude via a specialized analog to digital converter (ADC) and corresponding channels of the analyzer memory are incremented for each event.
Elemental Analysis of thin Films Using Inner Shell Electron Energy Losses
Authors: Johnson D. E. , Isaacson M.
Published: June 2020

The use of electron energy loss spectroscopy (ELS) for elemental analysis of thin films holds considerable promise. This technique has definite advantages in comparison with energy dispersive X-ray spectroscopy (EDS) for two fundamental reasons. First, the detection sensitivity is independent of the fluorescence yield, since for each inner shell excitation an energy loss electron exists as opposed to only a finite probability that an excitation will result in a X-ray emitted. Second, the information carrying energy loss electrons are contained in a small solid angle about 0° scattering angle as opposed to the resulting X-rays which are emitted uniformly over 4Π steradians. This means that a large fraction of the energy loss electrons can be detected (up to ∼90%) compared to only a small fraction (∼1%) of the emitted X-rays with an EDS system.
Characterization of Cotton Dust by Elemental Analysis
Authors: Fleming E. , Tucker P. , Hersh S.
Published: June 2020

Cotton dust has been identified as one of five common substances present in the workplace that a r e significant health hazards to industrial workers . The material reported here is part of a larger program being conducted by the School of Textiles to identify the etiological agent(s) causing byssinosis and to characterize the dust associated with cotton processing (1-3). The early results quickly verified that there are large amounts of both soluble and insoluble inorganic matterin cotton dusts.

Electron diffraction patterns were obtained from dust samples collected directly on carbon-coated grids from the air and from -water dispersed samples collected by a filtration system located in a model cotton card room (4). Identification of these diffraction patterns has not yet been completed because our attention has now focused on examining the water extractable components of cotton dusts with a newly acquired EDS-SEM system.
In Situ Observations of Precipitation on Dislocations in Fe-0.04wt%N
Authors: Beaven P. A. , Butler E. P.
Published: June 2020

Precipitation on dislocations can be a minor perturbation of homogeneous precipitation, or it can be the major mode of decomposition of an alloy. Previous work on the ageing of Fe-N alloys has established that the α” phase (Fe16N2) forms as thin discs on ﹛100﹜αplanes, and that nucleation can be predominantly homogeneous or heterogeneousαdepending on supersaturation and ageing temperature. An Fe-0.04wt%N alloy has been found suitable forin situobservations in the hot stage of the AEI EM7 HVEM operated at 500kV. Solution treatment is effected at 285°C and decomposition to α + α” takes place in the temperature range 150-250°C. Preliminary experiments have established that the microstructures producedin situare typical of aged bulk material.
In-Situ Analysis of the Trajectories and Speed of Gold Clusters Moving on Electron-Beam Cleaved (001) Mgo Surfaces.
Authors: Heinemann K. , Metois J.J. , Poppa H.
Published: June 2020

A previously described high-resolution TEM with UHV specimen chamber (10-7 Pa range), electron beam evaporation facilities, and fast speed/low electron exposure image recording facilities (1,2) was employed to observe the mobility of small gold clusters (13 Å mean diameter) on electron-beam cleaved MgO substrates (3). A deposit of 1.3 x 1015 gold atoms/cm2 was evaporated in 60 seconds immediately following the cleavage.

During the first 10 minutes following the deposition, many cluster mobility events were observed. The movements can be classified in two categories. One type of cluster mobility leads to coalescence and occurs usually within a few seconds (25 Å/s speed), see Fig.l. Whereas this kind of mobility was found to be predominant in previous cluster mobility studies of silver on amorphized graphite (4), cluster mobility leading to coalescence was only found in less than 20% of the observed mobility events for gold on (001) MgO. The majority of the cluster movements in the present system were characterized by an obvious tendency to avoid the proximity of other clusters (5).