bluuebunny/crossref_metadata_2025 huggingface dataset:
Brain Vessels Permeability to Ruthenium Red (RR) in the Adult Rat. A Qualitative X-Ray spectrometric Study with the Scanning Electron Microscope (SEM)
Authors: Arauz-Contreras Jorge , Feria-Velasco Alfredo
Published: June 2020

RR is a polycat ionic dye used as a cell coat marker in transmission electron microscopy studies. Also it is frequently used to examine uncoated biological material with SEM. Intraperitoneally (i.p.) administered RR produces flaccid paralysis both in mice and cats, whereas convulsions are observed when RR is intracisternally administered. However, when RR is i.p. injected to adultrats, convulsions are observed followin ganinitial period of flaccid paralysis, suggesting possible species differences in the response to RR. In the present work the passage of RR to brain parenchyma after its i.p. administration to adult rats was investigated using X-ray spectrometry coupled to SEM.
Inhibition of Compaction in the Preimplantation Mouse Embryo
Authors: Sutherland Ann E. , Calarco Patricia G.
Published: June 2020

The 8-cell mouse embryo progresses from a collection of loosely associated blastomeres into a spherical embryo by a process known as compaction. Scanning electron microscopy (SEM) was used to examine the effects of several inhibitors of cytoskeletal and cell-surface components on compaction in the mouse embryo.
Intracellular and Extracellular Acid Hydrolase Activity in the Drosophila Melanogaster Ovary
Authors: Altman Lawrence G. , Witkus R. , Vernon G. M.
Published: June 2020

Ovaries from wild type Drosophila melanogaster were incubated for acid phosphatase activity (pH 5). Following fixation in either 3.0% or 6.0% glutaraldehyde prepared in 0.1M cacodyiate buffer. Post-fixation was done in 1.0% osmium tetroxide and tissues were subjected to a graded series of acetone and infiltrated with Epon-Araldite. Control tissues were incubated without the substrate, in this case Bglycerophosphate. Ultrastructural integrity was checked against tissue prepared by omitting the incubation period completely. Thin and semi-thin sections were cut on an LKB ultramicrotome. In some instances, observations were recorded without uranyl acetate and lead citrate counterstaining.
Visualization of Antibody Transport in Rat Visceral Yolk-Sac Placenta
Authors: Jollie William P.
Published: June 2020

A technique has been developed for visualizing antibody against horseradish peroxidase (HRP) in rat visceral yolk sac, the placental membrane across which passive immunity previously has been shown to be transferred from mother to young just prior to birth. Female rats were immunized by injecting both hind foot pads with 1 mg HRP emulsified in complete Freund's adjuvant. They were given a booster of 0.5mg HRP in 0.1 ml normal saline i.v. after one week, then bred and autopsied at selected stages of pregnancy, viz., 12, 1 7 and 22 days post coitum, receiving a second booster, injected as above, five days before autopsy. Yolk sacs were removed surgically and fixed immediately in 2% paraformaldehye, 1% glutaraldehye in 0.1 M phosphate buffer with 0.01% CaCl2 at pH 7.4, room temperature, for 3 hr, rinsed 3X in 0.1 M phosphate buffer plus 5% sucrose, then exposed to 1 mg HRP in 1 ml 0.1 M phosphate buffer at pH 7.4 for 1 hr. They were refixed in aldehydes, as above, for 1 5 min (to assure binding of antigen-antibody complex). Following buffer washes, the tissues were incubated in 3 mg diaminobenzidine tetrahydrochloride and 0.01% H2O2 in 0.05 M Tris-HCl buffer for 30 min. After brief buffer washes, they were postfixed in 2% OsO4. in phosphate buffer at pH 7.4, 4°C for 2 hr, dehydrated through a graded series of ethanols, and embedded in Durcupan. Thin sections were observed and photographed without contrast-enhancement with heavy metals. Cytochemical reaction product marked the site of HRP (i.e., antigen) which, in turn, was present only where it was bound with anti-HRP antibody.
Dexamethasone Effect on Embryonic Chick Respiratory Epithelium
Authors: Richter M.R. , Blystone R.V.
Published: June 2020

Dexamethasone and other synthetic analogs of corticosteroids have been employed clinically as enhancers of lung development. The mechanism(s) by which this steroid induction of later lung maturation operates is not clear. This study reports the effect on lung epithelia of dexamethasone administered at different intervals during development. White Leghorn chick embryos were used so as to remove possible maternal and placental influences on the exogenously applied steroid. Avian lung architecture does vary from mammals; however, respiratory surfactant produced by the lung epithelia serves an equally critical role in avian lung physiology.
Analysis of Secretory Granule Containing Cells in the Sperm Duct of Aeolidia Papillosa (Nudibranchia)
Authors: Berio Robert
Published: June 2020

The reproductive tissue in the nudibranch Aeolidia papillosais spiralled around the digestive mid-gut, with male and female follicles being combined together in spherically shaped ovotestes. The male follicles are centrally localized with the sperm duct in the middle of this structure. Cells lining the sperm duct are of two basic types: 1) Sertoli-like nurse cells, and 2) differentiating sperm cells. Sperm cells accumulate in the lumen of the sperm duct durring periods of sexual inactivity. The Sertoli-like cells secrete substances which nourish the stored sperm cells as well as provide a supportive matrix in the lumen for the protection of the sperm cells durring ejaculation at mating time.
Membranous Glomerular Lesions
Authors: Spargo Benjamin H.
Published: June 2020

Non-inflammatory basement membrane changes constitute a growing number of glomerular peripheral capillary wall lesions. The widely varying nature of the basement membrane changes is important, both because of the contrasting prognosis of the different lesions and the new insights as to the pathogenesis.

Marked changes in the capillary wall in the absence of deposits causing thickening are seen in progressive hereditary nephritis. This lesion, frequently associated with Alport's syndrome, exhibits autosomal dominant inheritance, neural hearing loss, and ocular abnormalities. The renal disease presents clinically as hematuria and proteinuria, and has a poor prognosis.
Tumor Diagnosis
Authors: Mackay Bruce
Published: June 2020

The broadest application of transmission electron microscopy (EM) in diagnostic medicine is the identification of tumors that cannot be classified by routine light microscopy. EM is useful in the evaluation of approximately 10% of human neoplasms, but the extent of its contribution varies considerably. It may provide a specific diagnosis that can not be reached by other means, but in contrast, the information obtained from ultrastructural study of some 10% of tumors does not significantly add to that available from light microscopy. Most cases fall somewhere between these two extremes: EM may correct a light microscopic diagnosis, or serve to narrow a differential diagnosis by excluding some of the possibilities considered by light microscopy. It is particularly important to correlate the EM findings with data from light microscopy, clinical examination, and other diagnostic procedures.
Lanthanum in Human Red Cell
Authors: Keyhani Ezzatollah , Bland Eva
Published: June 2020

The human red cell contains four major glycoproteins : sialoglycoprotein or PAS 1; Band III; PAS 2 and PAS 3. With the exception of Band III, all other glycoproteins contain high levels of sialic acid. In addition, human red cells contain glycolipids which have been estimated to be less than 5% of the total lipids. Lanthanum has been used as tracer of extracellular space and as a probe for studies of Ca++metabolism across various types of cellular membrane. Biochemical studies led to the conclusion that lanthanum inhibition of Ca++metabolism was related to the sialic acid content of the cell membrane. The purpose of this communication is to describe the ultrastructural localization of lanthanum in human red cells under various experimental conditions.
The Myofibroblast Anchoring Strand is Both a Cell Tether and the Apparent Site of Collagen Fibril Assembly
Authors: Baur Paul S.
Published: June 2020

At the height of fibroplasia, myofibroblasts are the most prominent cells observed in the soft connective tissues of human granulations, wounds, and/or scars. Characteristic cytological features of the myofibroblasts include the prominent contractile bundles of actin micro-filaments 60-80 Å in diameter, the heavy concentrations of rough endoplasmic reticulum, and gap junctional complexes.
Developing Antler as a Model System of Fibrillogenesis
Authors: Speer D.P. , Kischer C.W.
Published: June 2020

Collagen fibers provide tensile strength to mammalian tissues and in many instances play morphogenetic as well as structural functional roles. While the directional orientation of these collagen fibers determines the tensile vectors within tissues, the three dimensional architecture of these collagen fiber systems has not been widely studied. Recent studies of the collagen architecture of articular cartilage, growth cartilage, and the developing deer's antler have employed physical optical principles with polarized light microscopy to demonstrate fiber fine structure in large areas of tissue. These studies have been supported by and complement those using electron microscopy techniques. The present study shows the fibrous architecture of the antler velvet, a tissue responsible for the annual production of a massive true bone structure in the deer.
X-Ray Spectroscopic Localization of Selenium in Four Patients Having Heavy Metal Intoxication
Authors: McMahon James T. , Tubbs Raymond R. , Bergfeld Wilma F.
Published: June 2020

Biopsies of four patients having various exposures to heavy metals were examined using SEM, TEM and X-ray microanalysis. Two patients having industrial exposure to inorganic mercury developed immune complex glomerulonephritis with a membranous distribution of IgG and C3. Within the proximal tubules of each patient were finely granular electron dense phagolysosomes. X-ray spectroscopic analysis of these inclusions demonstrated spectra characteristic of mercury and selenium.
Reactivity of Pulmonary Alveolar Cells to Crocidolite Asbestos Fibers
Authors: Sanders Charles L. , Adee Roy R.
Published: June 2020

Asbestos is a generic name for a group of hydrated mineral silicates that occur naturally in a fibrous form. The early interactions of asbestos fibers with alveolar cells in large part determines their long-term toxicity. Young adult, SPF, Fischer rats were given a single intratracheal instillation of 2 mg crocidolite asbestos suspended in 0.5 ml of 0.9% NaCl solution. About 80% of the fibers had lengths of less than 10 ym as measured on light micrographs of the fiber suspension. Two rats were killed at 3 hr, 1 d and 1, 4, 8, 12 and 16 wk after instillation and the lungs instilled with 8 ml McDowell - Trumps at 20 cm H2O. Lung tissue was dehydrated and sputtered coated with palladium-gold for SEM or post-fixed in osmium tetroxide, embedded in epoxy resin and sections stained with uranyl acetate and lead citrate for TEM.
Mass Measurement of Macromolecular Complexes with the Stem
Authors: Wall J. S. , Hainfeld J. F.
Published: June 2020

Mass measurement with the Scanning Transmission Electron Microscope (STEM) is a technique with wide application which has been developed in several laboratories. It is especially useful for particle identification in micrographs or in measurements of mass per unit length and mass distribution within a complex object.

The accuracy of mass measurements is determined by random errors (Counting statistics, substrate thickness variation) and systematic errors (biochemical degradation, salt, specimen preparation artifacts, radiation damage). Random errors can be estimated from previous studies and range from 1-10%.
Low Temperature X-Ray Microanalysis of Solid Biological Samples: Prospects and Problems
Authors: Echlin Patrick
Published: June 2020

Introduction

The advantages to be gained from using low temperatures in the preparation, examination and analysis of biological materials are well documented. The low temperature approach is particularly important in the analysis of low atomic number diffusible elements (x-ray microanalysis, electron spectroscopy and secondary ion analysis) and low molecular weight compounds (autoradiography, fluorescent microscopy and laser probe analysis). A recent paper discusses the application of these and other methods to the analysis of solid organic samples. This present discussion centres on the advantages and disadvantages of carrying out x-ray microanalysis on frozenhydrated (as distinct from frozen-dried) biological materal, with particular emphasis to solid samples. Two main methods have evolved for the analysis of frozen hydrated biological material; the use of frozen-hydrated sections and frozen-hydrated fracture faces. There are merits and short comings to both approaches and for any given tissue both methods can be complementary, neither are mutually exclusive.
Some Observations Concerning Tissue Collection for Electron Probe Microanalysis of Skeletal Muscle Electrolytes
Authors: Ingram F. Duane , Ingram Mary Jo
Published: June 2020

Considerable effort has been expended to establish the fidelity of the various techniques commonly employed for preparing biological soft tissue for intracellular electrolyte measurements. It generally is agreed that the necessary first step in preserving natural electrolyte distributions is to quick freeze tissue to a temperature near that of liquid nitrogen, -196°C. This is indeed necessary, but it is not sufficient. It is possible that large electrolyte and water shifts will occur during tissue collection and handling prior to immobilizing ions by freezing, thus compromising the sanple before the "necessary first step" has been taken. It is well known that with renal samples or erythrocytes, large water movements can occur in surprisingly short time intervals. In the short period required to clip and freeze a small sample of kidney, tubules collapse with loss of virtually all tubular fluid.
An Assessment of Ca-Naphthenate-Epon Mixtures as Standards for Calcium Quantification in Aortic Valve Leaflets
Authors: Colonna Kathryn N. , Breese Sydney S. , Sellers Susan C. , Deck J. David
Published: June 2020

Qualitative x-ray microanalytical studies used to demonstrate calcium in bioprosthetic aortic valves have shown that it occurs in a range of morphological forms. A consistent and reproducible standard for measuring calcium was necessary to investigate whether these forms represented varying concentrations of calcium. To provide such a standard, we tested a series of calcium naphthenate-epon mixtures.
Electron Probe Analysis of Muscle
Authors: Somlyo A. V. , Shuman H. , Somlyo A. P.
Published: June 2020

Electron probe analysis of frozen dried cryosections of frog skeletal muscle, rabbit vascular smooth muscle and of isolated, hyperpermeab1 e rabbit cardiac myocytes has been used to determine the composition of the cytoplasm and organelles in the resting state as well as during contraction. The concentration of elements within the organelles reflects the permeabilities of the organelle membranes to the cytoplasmic ions as well as binding sites. The measurements of [Ca] in the sarcoplasmic reticulum (SR) and mitochondria at rest and during contraction, have direct bearing on their role as release and/or storage sites for Ca in situ.
Applications of Electron Energy Loss Spectroscopy in Biology: Detection of Calcium and Fluorine
Authors: Leapman R. D.
Published: June 2020

Two classes of experiments, which look promising for the application of electron energy loss spectroscopy (EELS) involve the localization of cellular calcium and the detection of fluorine in labelled biological molecules. In this paper we present one example where EELS has proved complementary to energy dispersive X-ray analysis (EDX) for the detection of calcium, and some measurements on mass loss of fluorine which are relevant to the feasibility of the labelling technique.
Defect Studies in Solar Cell Silicon
Authors: Cunningham B.
Published: June 2020

Introduction

One of the requirements for low-cost silicon solar cells is that the silicon substrates be relatively inexpensive (compared to standard Czochralski and float-zone wafers). This requirement has led to the development of a number of techniques for growing silicon ‘ribbons’, e.g. edge defined film-fed growth (EFG), silicon-on-ceramic (SOC), ribbon-to-ribbon (RTR) and dendritic web. Details of these and other growth techniques can be found in ref. Most of the growth methods produce silicon ribbons which contain relatively high densities of structural defects, such as grain boundaries, twin boundaries and dislocations. In addition, small amounts of chemical impurities are introduced into the ribbons during growth from sources such as shaping dies (EFG), substrates (SOC, RTR), heat shields, etc.
The Electrical Behaviour of Individual Dislocations, Shockley Partials and Stacking Faults
Authors: Ourmazd A. , Wilshaw P.R. , Webert E. , Gottschalkt H. , Booker G.R. , Alexander H.
Published: June 2020

Introduction The importance of the effect of defects, of which dislocations form an important class, on the electrical properties of semiconductors needs no emphasis. Although the electrical behaviour of dislocations has been studied by a variety of techniques for many years, no overall understanding has yet emerged. In our view this is due to three main features; (i) because of lack of spatial resolution, electrical information has been obtained from large aggregates of dislocations containing many different defect types, (ii) dislocations studied by different authors have in general been produced under different conditions and (iii) few attempts have been made to characterise the structure of the dislocations studied electrically. It has been the object of the present study to overcome these shortcomings by obtaining electrical data from individual dislocations, produced under well-defined conditions, whose structure has been characterised in detail by various TEM techniques in conjunction with electron paramagnetic resonance (EPR) measurementions. Electrical information has been obtained at high spatial resolution (≤ 0.3μm) by the EBIC mode of the SEM. The EBIC contrast C can be related to the position of the primary dislocation level EO, the dopant concentration Nd, and the temperature T1.
Microstructural Contributions to Stress Corrosion Cracking in High Strength Steels
Authors: Padmanabhan R. , Wood W. E.
Published: June 2020

The effects of microstructural variables upon stress corrosion cracking resistance of 300M steel in 3.5% NaCl solution have been studied. Table 1 lists KIsccvalues for three heat treatment conditions. The martensite substructure was predominantly twinned plates for conventional heat treatment and dislocated laths for both high temperature and step heat treatments. A typical twinned region observed in the conventional heat treatment is shown in Fig. 1. Such twinned regions were less frequent in the other heat treatments. Both cementite and epsilon carbide were seen in all cases, as illustrated in Figs. 2 and 3 for conventional heat treatment. Epsilon carbide was usually observed within large grain boundary nucleated laths (autotempered martensite), with definite habit planes and growth directions. The formation of such laths have been discussed previously. Retained austenite, mostly in the form of interlath films, was observed in all cases with increased amounts present in coarser grained structures (Fig. 4).
Influence of Heat Treatment on the Failure Mode of High Strength Steel in Aggressive Environments
Authors: Padmanabhan R. , Wood W. E.
Published: June 2020

The predominant fracture mode during hydrogen assisted environmental failure of 300M steel is intergranular. However, limited attempts have been made to study the failure mode, both as a function of applied stress intensity and as a function of heat treatment. In this investigation, studies were conducted for 300M steel specimens subjected to load in a 3.5% NaCl solution.
Effects of Temperature and Incoherent Dispersoids on Slip Dispersal in AI-3Li Alloys
Authors: O’Neal J. E. , Sankaran K. K. , Sastry S. M. L.
Published: June 2020

Binary Al-Li alloys containing 1.5-3.0 wt% Li are hardened by precipitation of the metastable, coherent δ' (Al3Li) phase having an Ll2 type crystal structure. Plastic deformation in these alloys occurs by the shearing of δ' precipitates by glide dislocations, resulting in the formation of planar slip bands and therefore stress concentrations at grain boundaries and slip band intersections. These stress concentrations become potential crack nucleation sites in the early stages of deformation.
Signal/Noise Ratio and Elemental Detectivity by Eels
Authors: Egerton R. F.
Published: June 2020

An important parameter governing the sensitivity and accuracy of elemental analysis by electron energy-loss spectroscopy (EELS) or by X-ray emission spectroscopy is the signal/noise ratio of the characteristic signal.
Electron Energy-Loss Spectroscopy used for Localized Compton Scattering
Authors: Bourdillon A.J. , Williams B.G.
Published: June 2020

It has been shown that electron-energy loss spectroscopy (EELS) can be used to measure the ground state momentum of electrons in a sample by Compton scattering. Furthermore electrons passing through a crystalline foil suffer orientation effects explained by dynamical theory. Here experiments are described which attempt to measure momentum distributions at different parts of the unit cell.
High Resolution Replication of Organoclay Surfaces
Authors: Barker W. W. , Rigsby W. E. , Hurst V. J. , Humphreys W. J.
Published: June 2020

Experimental clay mineral-organic molecule complexes long have been known and some of them have been extensively studied by X-ray diffraction methods. The organic molecules are adsorbed onto the surfaces of the clay minerals, or intercalated between the silicate layers. Natural organo-clays also are widely recognized but generally have not been well characterized. Widely used techniques for clay mineral identification involve treatment of the sample with H2 O2 or other oxidant to destroy any associated organics. This generally simplifies and intensifies the XRD pattern of the clay residue, but helps little with the characterization of the original organoclay. Adequate techniques for the direct observation of synthetic and naturally occurring organoclays are yet to be developed.
A Technique for Measuring Thickness and Observing Cross Sectional Microstructure of Submicron Films on Glass
Authors: Benoit Robert E.
Published: June 2020

This technique provides a simple measure of absolute thickness and a view of cross sectional microstructure of thin films on glass. The method has been successfully used to study both conductive and non-conductive films ranging in thickness from less than 200 angstroms to over 5000 angstroms.
Void Formation in Neutron-Irradiated Ti-Al Alloys
Authors: Sprague J. A.
Published: June 2020

Although it is generally thought that Ti1 and Ti-alloys2 are resistant to neutron-irradiation-induced void formation, this conclusion is prinicipally based on relatively low-fluence exposures (<1 X 1022 neutrons/cm2) and limited heavy-ion irradiation experiments3. As part of an investigation of the mechanisms controlling the irradiation responses of Ti and its alloys, two Ti-Al alloys, containing 3 and 6 wt.% Al, respectively, and a pure Ti control material, prepared by the same procedures used for the alloys, have been examined by TEM following neutron irradiation in the EBR-II Reactor to a fluence of 5 X 1022 Neutrons/cm2, E>0.1 MeV (∿35 displacements per atom, or dpa), at a temperature of 500°C.
Analytical ELectron Microscopy Characterization of Basalt Glass Ceramics
Authors: Thomas L. E. , Chick L. A. , Lokken R. O.
Published: June 2020

Radioactive waste produced by nuclear reactors poses long term environmental hazards if not adequately immobilized and stored. As part of a program for developing basalt-based waste forms with high leach durability, analytical electron microscopy has been used to identify and chemically analyze the phases in several basalt glass/ceramic materials.
Metamictization in Zircon
Authors: Chan Ignatius Y. , Buseck Peter R.
Published: June 2020

The phenomenon of radiation damage in minerals is of interest because of its bearing on both radioactive waste disposal and the determination of geological age. It is important to understand the defects produced in minerals at the different stages of structural damage by radiation. Zircon was chosen in this investigation because it is a widespread silicate in metamorphic and igneous rocks and is commonly partly or totally metamict.
Invariant Line and Loss of Coherency in Mo(C) System
Authors: Lang Jean-Marc
Published: June 2020

This paper reports a detailed study of the loss of coherency of h.c.p. Mo2C precipitates in an b.c.c. Mo matrix. The existence of an invariant line in the phase transformation is experimentally verified.

The experiments were performed on a very pure Mo - 300 at. ppm C alloy, quenched from 2300K at a rate of 2500K/s to prevent heterogeneous nucleation. The specimens were subsequently annealed 1h at 1073K.
Diffusion Induced Grain Boundary Migration in Ion-Beam Mixed Fe-AL
Authors: Prasad Shankara K. , Herman Herbert , King Alexander H. , Goland Allen
Published: June 2020

Ion beam intermixing is a newly investigated process wherein an ion beam is used to induce a reaction between a deposited thin layer and the substrate. The ion beam induced intermixing and microalloying at the interface can be due to three processes: 1. Recoil implantation 2. Cascade mixing 3. Radiation enhanced diffusion. Mixing due to recoil implantation has been studied by Nelson and was shown to result in very shallow mixed layers. However, in their recent investigation of Pt-Si, Pd-Si and Al-Ge and other systems, Tsaur et.al, have observed the formation of a thick surface alloy which is metastable in nature. They attribute this intermixing of the deposited thin film and the substrate, and the eventual "epitaxial" growth, to cascade overlap and radiation enhanced bulk diffusion. The present work provides evidence for the role played by grain boundaries in both intermixing and grain growth.
Sem Studies of Co-Cr-Mo Surgical Implant Alloy Corrosion Behavior
Authors: Van Orden Ann Chidester , Chidester John L. , Fraker Anna C. , Sung Pei
Published: June 2020

The influence of small variations in the composition on the corrosion behavior of Co-Cr-Mo alloys has been studied using scanning electron microscopy (SEM), energy dispersive x-ray analysis (EDX), and electrochemical measurements. SEM and EDX data were correlated with data from in vitro corrosion measurements involving repassivation and also potentiostatic anodic polarization measurements. Specimens studied included the four alloys shown in Table 1. Corrosion tests were conducted in Hanks' physiological saline solution which has a pH of 7.4 and was held at a temperature of 37°C. Specimens were mechanically polished to a surface finish with 0.05 µm A1203, then exposed to the solution and anodically polarized at a rate of 0.006 v/min. All voltages were measured vs. the saturated calomel electrode (s.c.e.).. Specimens had breakdown potentials near 0.47V vs. s.c.e.
Microscopic Studies of Sliding Wear on Titanium
Authors: Nutt S. R. , Ruff A. W.
Published: June 2020

A primary objective of any wear study is to relate the wear and surface damage to corresponding changes in the subsurface microstructure. Transmission electron microscopy (TEM) is well-suited to this task, enabling one to image with good spatial resolution the internal structure beneath a worn surface. This approach is currently being applied along with scanning electron microscopy (SEIM) to the study of dry sliding wear of titanium against itself and other materials. Titanium is of particular interest because it is a metal with hexagonal structure and only nine available slip systems for plastic deformation by dislocation glide. Cubic metals such as iron and copper, on the other hand, have twelve slip systems and have been studied extensively in wear. Although the wear and friction properties of titanium generally are not good, titanium has seen increasing use in components involving mechanical wear because of its good corrosion properties and high specific strength.
Initial Stages of the Oxidation of Fe-Cr Alloys
Authors: Labun P.A. , Kuroda K. , Mitchell T.E.
Published: June 2020

The growth of oxide on Fe-Cr alloys, containing 3, 9, 12 and 18 wt.%Cr has been investigated both in-situ and ex-situ with electron microscopy using a Hitachi HU-650B HVEM and a Philips EM400T. Some specimens were electrochemically polished and oxidized at 700 to 800°C in 10-3 torr of air or 20 torr of dry oxygen; others were oxidized and then back-thinned to electron transparency. Fe3O4 containing trace amounts of Cr was observed to nucleate on the 3%Cr specimens while M3O4 (M = Fe, Cr) and/or ϒ-M2O3 nucleated on the higher Cr specimens.
X-Ray Diffraction and Transmission Electron Microscopy Study of One-Dimensional Disorder Polytypes in SiC
Authors: Dubey M. , Singh S. R. , Singh G.
Published: June 2020

Silicon carbide crystallizes into several structural modifications whose c-periodicities vary from 1 nm to more than 100 nm. Its high period structures are found to consist of intergrowth of smaller period structures at the unit cell level. The X-ray diffraction studies show that SiC crystals often possess one-dimensional disorder which is characterized by continuous streaks in X-ray diffraction patterns along ho.1 reciprocal lattice rows. However, it is shown that these streaks can also arise as a result of extremely high c-periodicities of the crystals as their ho.1 spots cannot be resolved easily. This contribution reports the observation of only few representative cases of so-called one-dimensional disordered crystals as observed in their X-ray and electron diffractions with lattice imaging.
Eels of Gases in the Electron Microscope
Authors: Burgner R.P. , Krivanek O.L. , Swann P.R.
Published: June 2020

Interest in the role of microstructure in chemical reactions (particularly in catalysis) has stimulated the development of environmental cells (E-cells) for the transmission electron microscope. A knowledge of the local changes in chemical composition that occur during these reactions is useful but difficult to obtain by conventional energy-dispersive Xray techniques because of the physical requirements for a gas-tight cell. By contrast, electron energy loss spectroscopy (EELS) presents no additional instrumentation difficulties and may be used to monitor low and high-Z chemical changes in both solid and gas phases throughout the chemical reaction.
The Crystalline to Amorphous Transition of Dehydrated Ca a Zeolite
Authors: Lodge E.A.
Published: June 2020

Zeolite A, a hydrated, crystalline framework aluminosilicate containing exchangeable cations in tunnels and cages, is a potential matrix for the burial of radioactive waste. The material is extremely sensitive to electron irradiation and the crystalline to amorphous transition has been studied using a JEOL 200CX electron microscope.
Analytical Electron Microscopy of Solid Catalysts
Authors: Delannay F.
Published: June 2020

Practical catalysts are usually intricate mixtures of phases which cannot be characterized separately unless looked at below the micron scale. For about two decades, electron microscopy has been a priviledged complement to selective chemisorption methods for the study of supported metal catalysts. Until recently, however, reliable tools allowing characterization of oxide and sulfide catalysts (e.g. for selective oxidation and hydrodesulfurization reactions) have been lacking. This contribution aims at illustrating the new insights into the understanding of these systems which have been provided by the combination of thin film X-ray microanalysis and electron microdiffraction within a conventional transmission electron microscope with STEM and EDS attachments.
Kinematically Allowed Reflections and Reflections Caused by Scattering VIA Holz
Authors: Ishizuka K. , Taftø J.
Published: June 2020

The invention of commercial analytical electron microscopes where convergent beam electron diffraction (CBED) patterns form small areas (~100Å diameter) are routinely obtained has made CBED a powerful technique for the determination of crystal symmetries. The purpose of this note is to point out that by using this technique, one can often immediately find out whether a reflection is kinematically allowed or is due to scattering via HOLZ from the features of the convergent beam disk under consideration. We use crystals with the spinel structure (Fd3m, no 227) as examples. The spinel structure is interesting from this point of view, because it was proposed, based on the observation of the (200) reflection in selected area electron diffraction (SAED) patterns, tht the established space group of spinel was wrong.
Analysis of Folz Lines in Selected Area Channeling Patterns
Authors: Madden M. C. , Hren J. J.
Published: June 2020

Fine lines exist in electron channeling patterns near the centers of low index poles. These lines were visible in early patterns obtained by Coates (1968) and Wolf and Coane (1973) but have not been analyzed or indexed. The area containing the fine structure is at a higher background intensity than the rest of the pattern (Figure 1) and occupies an angular width of ~2°. Visibility of the fine structure is improved by magnifying the area around the pole and either increasing the DC suppression or differentiating the signal. The fine structure of the (111) pole of silicon at 35 kV is shown in Figure 2.
A High Resolution Study of G.P. Zones in Aluminum - 4.2 at % Silver
Authors: Gronsky R.
Published: June 2020

The phenomenon of clustering in Al-Ag alloys has been extensively studied since the early work of Guinierl, wherein the pre-precipitation state was characterized as an assembly of spherical, ordered, silver-rich G.P. zones. Subsequent x-ray and TEM investigations yielded results in general agreement with this model. However, serious discrepancies were later revealed by the detailed x-ray diffraction - based computer simulations of Gragg and Cohen, i.e., the silver-rich clusters were instead octahedral in shape and fully disordered, atleast below 170°C. The object of the present investigation is to examine directly the structural characteristics of G.P. zones in Al-Ag by high resolution transmission electron microscopy.
A Library of Electron Energy Loss Spectra at leV Resolution
Authors: Ahn C. C. , Krivanek O. L.
Published: June 2020

The need for a reference "library" of EELS edges has recently been recognized by several workers, and a partial EELS library has become available for the most common elements at about 3eV resolution. Our work aims at expanding this pool of known spectra to less common elements, and improving the energy resolution to ≤ leV. It is hoped that the resultant library will be useful in several ways: as a source of experimental spectra for testing cross-section calculations and spectra quantitation programs, as a data bank of high-resolution "fingerprint" spectra for elemental identification of unknown samples, and as an educational tool showing the trends and features appropriate to whole classes of elements of similar atomic number.
Rad: A Comprehensive Software System for Analytical Electron Microscopy
Authors: Carr M. J. , Chambers W. F.
Published: June 2020

An analytical electron microscope (AEM) provides the capability of obtaining both compositional and crystallographic information. While the acquisition and reduction of x-ray EDS data is generally done by a small computer, the acquisition and analysis of electron diffraction data has remained a manual, off-line technique. A recently described technique1 has made possible the real-time acquisition and reduction of electron diffraction data with an AEM. However, as is the case with EDS analysis, electron diffraction analysis requires that a rather large body of data be processed in order to produce a relatively simple result.
A Monte Carlo thin Film Simulation for Microcomputers
Authors: Joy D.C.
Published: June 2020

Monte Carlo simulations are now widely used as a means of studying the details of electron solid interactions (Heinrich et al 1976). The use of this technique has, however, been limited by the perception that a large computer, and a substantial investment in computing time are required to obtain useful results. This paper describes a Monte Carlo simulation, written in BASIC that is implemented on an APPLE micro-computer, and is readily adapted to most other "personal" computers.
Sputter Coated Carbon Specimens for Sem Performance Testing
Authors: Black D.R. , Ballard D.B.
Published: June 2020

Resolution capability of a SEM is often demonstrated by the smallest spacing between two distinct images on a photomicrograph. Unfortunately, this determination of resolution is subjective, due in part to the resultant fuzziness of the image edges often seen at high magnification. This lack of edge sharpness and the uncertainty in the true edge location degrades the precision and accuracy of the measurement to a significant degree.
X-Ray Analysis of Frozen Hydrated Sections:The Unconventional Approach
Authors: Beeuwkes R. , Saubermann A. , Echlin P. , Churchill S.
Published: June 2020

Fifteen years ago, Hall described clearly the advantages of the thin section approach to biological x-ray microanalysis, and described clearly the ratio method for quantitive analysis in such preparations. In this now classic paper, he also made it clear that the ideal method of sample preparation would involve only freezing and sectioning at low temperature. Subsequently, Hall and his coworkers, as well as others, have applied themselves to the task of direct x-ray microanalysis of frozen sections. To achieve this goal, different methodological approachs have been developed as different groups sought solutions to a common group of technical problems. This report describes some of these problems and indicates the specific approaches and procedures developed by our group in order to overcome them. We acknowledge that the techniques evolved by our group are quite different from earlier approaches to cryomicrotomy and sample handling, hence the title of our paper. However, such departures from tradition have been based upon our attempt to apply basic physical principles to the processes involved. We feel we have demonstrated that such a break with tradition has valuable consequences.
Electron Microscopy in Medicine
Authors: Stanley Bennett H.
Published: June 2020

Medicine can be regarded as an applied biological science, much as engineering involves applications of the physical sciences. Just as the physical sciences and engineering participate in regenerative feed-back loops in which each field strengthens the other as well as itself, so medicine and biology depend on each other. Fundamental conceptual and technical advances in biology come to be reflected in medicine.

How did the revolution in cytology brought to pass by electron microscopy come to pervade the field of medicine? Before physicians, or anyone else, can use a field of knowledge, they must know it. Large scale dissemination of a complex set of concepts through a professional body is accomplished most thoroughly by incorporation and integration of that field into the instructional curriculum of the professional schools. So far as I am aware, the first formal incorporation into a medical curriculum of structural biological knowledge based on electron microscopy anywhere in the world was initiated in the Anatomy Department at the University of Washington School of Medicine in Seattle in 1948.
Ultrastructural Alterations in Hela Cells Induced by Spider Venom
Authors: McClendon Dale E. , Morgan Paul N. , Soloff Bernard L.
Published: June 2020

It has been observed that minute amounts of venom from the brown recluse spider, Loxosceles reclusa, are capable of producing cytotoxic changes in cultures of certain mammalian cells (Morgan and Felton, 1965). Since there is little available information concerning the effect of venoms on susceptible cells, we have attempted to characterize, at the electron microscope level, the cytotoxic changes produced by the venom of this spider.

Cultures of human epithelial carcinoma cells, strain HeLa, were initiated on sterile, carbon coated coverslips contained in Leighton tubes. Each culture was seeded with approximately 1x105 cells contained in 1.5 ml of a modified Eagle's minimum essential growth medium prepared in Hank's balanced salt solution. Cultures were incubated at 36° C. for three days prior to the addition of venom. The venom was collected from female brown recluse spiders and diluted in sterile saline. Protein determinations on the venom-were made according to the spectrophotometric method of Waddell (1956). Approximately 10 μg venom protein per ml of fresh medium was added to each culture after discarding the old growth medium. Control cultures were treated similarly, except that no venom was added. All cultures were reincubated at 36° C.
Buffered Formalin for Primary Fixation and Preserving Tissue for a Long Time
Authors: Yamamoto I. , Rosario B.
Published: June 2020

It is known that suitably buffered formaldehyde can be used as a killing agent and primary fixative for electron microscopy(Pease).

We were interested in how long buffered formalin preserves tissue. Thus, in this study, an attempt was made to observe ultrastructure of surgical material fixed and stored in buffered formalin for a long time.

Pieces of fresh tissues were, fixed in buffered formalin at 4°C for one hour, and then placed at room temparature for weeks and months without changing solution.

Buffered formalin used was prepared as follows:

A. “ reagent grade ” formalin

B. 0.05 M Sorensen's phosphate buffer, pH 7.2-7.4 mix 1 part of A and 9 parts of B to make 10 % solution.

Pieces of tissues were then minced and postfixed in 1 % osmic acid buffered with veronal acetate for two hours or more. Postfixed tissues were then embedded in an epoxy resin mixture through standard technique. Thin sections were stained with uranyl acetate followed by lead, and examined in a Hitachi 11C electron microscope.
Basement Membrane of Smooth Muscle Cell and Its Association With Elastic Tissue in Aorta
Authors: Yu S.Y. , Sun C.N.
Published: June 2020

Organization and connection between smooth muscle cells and elastic tissues in aortas is not elucidated. Keech believed that the smooth muscle cells anchore on the elastic tissue. Among the fibers of the aortic connective tissue, there are collagen, elastic tissue and microfibril. This communication is to present evidence that the microfibrils which are derived from the basement membrane of the smooth muscle cells, play a role for connection between the smooth muscle cells and the elastic tissues.

Thoracic aortas from new born rats were fixed with Dalton's chrom-osmium solution, embedded in Epon 812 and stained with uranyl acetate and lead citrate. Our previous work showed that the smooth muscle cell synthesized the elastic tissue during its differentiation prior to completing the process. At the actively synthesizing site of the cell, the basement membrane was replaced by numerous microfibrils (Fig. 1 MF). The microfibrils extended from the basement membrane toward the preformed elastic lamellae (EL), occasionally surrounded scallop-shaped elastic unit (EU).
Problems in Myogenesis Terminology in Electron Microscopy
Authors: Conen P.E. , Balis J.U. , Bell C.D.
Published: June 2020

Myogenesis in man was studied using muscle from 19 fetuses of 8 to 16 weeks gestation which were processed with standard osmium-Epon or glutaraldehyde-osmium-Epon schedules and sections were stained in uranyl acetate and/or lead hydroxide. Particular emphasis was given during this study to presence of basement membrane and myofilaments as additional aids in classification of cell types present in developing muscle.

Electron microscopy permits accurate identification of fibroblasts and early cells of muscle series and has been used in studies of myogenesis in chick, and rat. Light microscopy definitions for premyoblasts and myoblasts, and for myocytes at the myotube and muscle fiber stages of development are difficult to apply to electron microscopic studies without modification. For example the term myoblast was used differently by Tello, Katznelson and Boyd to designate a cell destined to become muscle but not recognizable as a muscle cell.
Quantitative Examination of the Myelinated Fibers in Electron Micrographs of the Cat’s Visual Cortex
Authors: Haug Herbert
Published: June 2020

It is possible to measure the length of a linear tract with the aid of stereological methods. The myelinated fibers of the nervous system are such linear tracts. The myelinated fibers of the cerebral cortex have different directions, therefore it is impossible to measure their length directly with the light microscope. Furthermore some of them are very small and their diameters can only be measured in electron micrographs.

The correctness of stereological measuring of the length of myelinated fibers has been proved by the aid of other methods (HAUG 1967). The subject of investigation was the comparison of the upper part of the griseum of cerebral cortex (layer I, II and III) and the album near the border of visual cortex. Both parts are different in quantity and thickness of their myelinated fibers. After fixation by perfusion with glutaral-dehyde-phosphatbuffer and a short postfixation with osmium-tetroxyde small blocks of both parts were embedded in Vestopal with a random orientation.
Strandedness of Chromosomes From Two Species of Vicia
Authors: Wolfe Stephen L. , Martin Peter G.
Published: June 2020

Recent experiments (1) have revealed subchromatid structure in chromosomes of Vicia faba after trypsin digestion. Although the chromosome number is the same in V. faba and another member of this genus, V. sativa. V. faba has been found to have approximately 5 times the amount of DNA per nucleus as V. sativa (2). Because it is unlikely that V. faba has genetic loci not represented in sativa in numbers sufficient to account for the noted differences in DNA content, it seems probable that the differences are a reflection of redundancy of the DNA in V. faba, either laterally, to produce true multistrandedness, or linearly, to produce a longer singlestranded chromosome. In an effort to investigate this possibility, chromosomes from the two species were studied with both light and electron microscopy to compare the apparent strandedness of the two species both untreated and after trypsin digestion.
Scanning Electron Microscopy Using Cathodoluminescence
Authors: Pease R. F. W. , Hayes T. L.
Published: June 2020

It is desirable to derive molecular information from many specimens with a resolution better than can be achieved with a light microscope. In the conventional electron microscope such information is usually only obtained indirectly by staining the specimen with a stain containing a heavy metal.

In the scanning electron microscope (SEM), the optical focusing is independent of the contrast process; this allows a wide variety of contrast mechanisms e.g. secondary electrons emission which gives information of surface topography and voltage, and X ray emission which reveals atomic content.

Some specimens emit light when bombarded with electrons. This process, cathodoluminescence, is characteristic of the molecular content of biological specimens and therefore we are investigating using this emitted light to build up scanning electron micrographs. Although similar information can be obtained using ultra violet fluoresence microscopy, the scanning electron technique offers the possibility of improved resolution since this is limited fundamentally by the electron probe diameter which can be 50Å or smaller.