bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dislocation structures around SiO2 Particles in aged Cu-Cr-SiO2
Authors: Long N.J. , Loretto M.H. , Lloyd C.H. 
Published: June 2020

IntroductionThere have been several t.e.m. studies (1,2,3,4) of the dislocation arrangements in the matrix and around the particles in dispersion strengthened single crystals deformed in single slip. Good agreement has been obtained in general between the observed structures and the various theories for the flow stress and work hardening of this class of alloy. There has been though some difficulty in obtaining an accurate picture of these arrangements in the case when the obstacles are large (of the order of several 1000's Å). This is due to both the physical loss of dislocations from the thin foil in its preparation and to rearrangement of the structure on unloading and standing at room temperature under the influence of the very high localised stresses in the vicinity of the particles (2,3).This contribution presents part of a study of the Cu-Cr-SiO2 system where age hardening from the Cu-Cr and dispersion strengthening from Cu-Sio2 is combined.
Formative time and structure of martensite from amorphous FeNi films
Authors: Bostanjoglo O. , Liedtke R. 
Published: June 2020

Using a fast detector the applicability of CTEM was extended to follow phase transformations in the nanoseconds range. Iron-rich FeNi films vapour-quenched at 4 K grow in an amorphous state with peculiar crystallographic and magnetic properties (1). On exceeding a critical thickness or on heating amorphous films with inferior thickness up to a critical temperature, the films martensiticly crystallized. This diffusionless transformation occurred in such films where the amorphous phase was stabilized by stress and not by reacting gases.The present paper reports investigations on both the structure of martensite and on the propagation of martensitic crystallization of amorphous 70 at % FeNi films. They were grown at 4 K on carbon foils in the EM as previously described (1). The propagation of the phase transformation was investigated by following the change of the bright-field image intensity with fast scintillator, photomultiplier and oscilloscope. Crystallization processes occurring in areas of 1.5 μm ∅ and within 10 ns were resolved in first experiments (fig. 3).
Scalp pilar tumor with intranuclear fibrils
Authors: Lim B. S. 
Published: June 2020

Pilar tumor is considered by some to be a low grade squamous carcinoma. Although there are instances of metastasis to regional nodes, the tumor is extremely slow growing and recurrence are rare. Electron microscopic examination of this tumor revealed new morphological finding of intranuclear fibrils.Description of the tumor: A large, nodular, fungating and focally ulcerated tumor was noted in the center of the scalp of a mental patient. This mass measured 8.0x4.0x3.0 cm. On cut surface the tumor was well circumscribed and appeared to extend deep into the subcutaneous tissue. On inspection this lesion was gray-white and granular and in some areas there were foci of calcification, hemorrhage and necrosis.
Ultrastructure of mesotheliomas
Authors: Dardick Irving 
Published: June 2020

With the extensive industrial use of asbestos in this century and the long latent period (20-50 years) between exposure and tumor presentation, the incidence of malignant mesothelioma is now increasing. Thus, surgical pathologists are more frequently faced with the dilemma of differentiating mesothelioma from metastatic adenocarcinoma and spindle-cell sarcoma involving serosal surfaces. Electron microscopy is amodality useful in clarifying this problem.In utilizing ultrastructural features in the diagnosis of mesothelioma, it is essential to appreciate that the classification of this tumor reflects a variety of morphologic forms of differing biologic behavior (Table 1). Furthermore, with the variable histology and degree of differentiation in mesotheliomas it might be expected that the ultrastructure of such tumors also reflects a range of cytological features. Such is the case.
On the assembly and structural modulation of lens fiber junctions
Authors: Benedetti E.L. , Dunia I. , Lien Do Ngoc , Vallon O. , Louvard D. , Bloemendal H. 
Published: June 2020

In the eye lens emerging molecular and structural patterns apparently cohabit with the remnants of the past. The lens in a rather puzzling fashion sums up its own natural history and even transient steps of the differentiation are memorized. A prototype of this situation is well outlined by the study of the lenticular intercellular junctions. These membrane domains exhibit structural, biochemical and perhaps functional polymorphism reflecting throughout life the multiple steps of the differentiation of the epithelium into fibers and of the ageing process of the lenticular cells.The most striking biochemical difference between the membrane derived from the epithelium and from the fibers respectively, concerns the presence of the 26,000 molecular weight polypeptide (MP26) in the latter membranes.
Distribution of the main intrinsic polypeptide in lens fiber membrane domains
Authors: FitzGerald Paul G. , Horwitz Joseph , Bok Dean 
Published: June 2020

The lens fiber cell of the vertebrate eye is a postmitotic, highly differentiated cell which is derived from the lens epithelium. Upon differentiation into lens fibers, the epithelium expresses a unique membrane protein (Main Intrinsic Polypeptide, MIP) with a molecular weight in excess of 26,000. These lens fiber cells are extraordinarily rich in intercellular junctions which can occupy up to 64% of the cell surface. Lens fiber junctions, frequently referred to as “gap junctions”, co-purify with MIP and it has therefore been suggested from biochemical evidence that MIP is a junctional protein.Electron microscopic immunoferritin studies in which rabbit anti-bovine MIP antiserum was incubated with isolated bovine lens fiber membranes have shown that MIP is present in abundance in pentalaminar profiles conventionally regarded as lens junctions (Figure 1).
Backscattered-electron imaging of the colloidal gold surface marker
Authors: de Harven E. , Leung R. , Christensen H. 
Published: June 2020

A variety of markers have been used for surface labeling with the scanning electron microscope (1). They are all recognized in the secondary electron imaging (SEI) mode on the basis of their characteristic sizes and shapes. This makes it difficult, however, to recognize unambiguously markers of small size (smaller than 40 nm). Unfortunately, markers of such size are needed if one wishes to minimize steric hindrance phenomena (2) and therefore obtain high efficiency labeling. We have found that the atomic number contrast of the colloidal gold marker, expressed in the backscattered electron imaging (BEI) mode, alleviates this difficulty to a significant extent (3).Human peripheral blood leukocytes, separated by sedimentation in presence of Dextran, were attached to poly-1-lysine pretreated carbon coated grids. The cells were then fixed for 5 min with 0.25% solution of buffered glutaraldehyde, pH 7.2, extensively rinsed with 0.1% glycine in PBS, and incubated for 30 min, at room temperature with an IgM monoclonal antibody (D2) specifically recognizing, a surface antigen of mature granulocytes.
Mercury in primate Paneth cells following methylmercury hydroxide ingestion
Authors: Crooker A. R. , Johnson D. E. , Mottet N. K. 
Published: June 2020

The toxicity of mercury and its compounds is widely recognized. Symptoms of mercury intoxication vary greatly depending on mode of entry, form of mercury, dose, and duration of exposure. In humans, the principal toxic effects of inorganic mercury involve the liver and kidney. Organic mercurials such as methylmercury have a more pronounced effect on the central nervous system.Pharmacological studies suggest an intestinal elimination of organic mercurials and the possibility of an intestinal lesion associated with mercury. Autoradiographic studies have indicated that uptake of 203HgCl2 by rat paneth cells exceeded that of other cells of the small intestine. Paneth cells line the bottoms of intestinal crypts. They are pyramidal in shape with basally located nuclei and large secretory granules in their apical aspect which contain the bacteriolytic enzyme lysozyme.
Subcellular localization of actin in chlorella
Authors: Michaels A. , Kriho V. , Solomonson L. 
Published: June 2020

Although most often thought of as a contractile protein, actin has been localized and isolated from many non-muscle eukaryotic cells. The function of actin has also been described in certain algal cells. However, little is known regarding the subcellular distribution of actin and its relationship to function in algal cells.Using the immunocytochemical techniques of Wolosewick and co-workers, we have determined the subcellular location of actin in the unicellular green algae, Chlorella vulgaris.Pellets of Chlorella were fixed in 0.25% glutaraldehyde (EMS) in growth media for 1 hr on ice. The cells were washed (2X) with 10mM potassium phosphate buffer, pH 7.5. These cells were maintained on ice in phosphate buffer until dehydration and embedding in polyethylene glycol (PEG) (MW3350). PEG is a water miscible wax which can be removed easily from the section.
Fine structure of crack in ceramics
Authors: Kakibayashi Hiroshi , Nagata Fumio 
Published: June 2020

Many kinds of ceramics have been developed providing enough insulation, heat conduction or shock resistance. For the characteristics of strong toughness of the ceramics, movements of cracks by applying a force are noteworthy, because most ceramics are hardly distorted.In the present works, behavior of cracks in ceramics is observed with high resolution electron microscopy. Silicon nitride (Si3N4) ceramics were made by sintering in nitrogen atmosphere at 1800°C. Some Y2O3 and AlN were added to assist the sintering. A piece of the ceramics was sliced and polished mechanically untill 20μm in thickness. The specimen was mounted on a single hole grid, and was thinned with an ion etching equipment to be thin enough to observe.
Growth of near noble metal Pd and Pt thin film silicides morphology and structure
Authors: Alessandrini E. I. , Aboelfotoh M. O. 
Published: June 2020

Considerable interest has been generated in solid state reactions between thin films of near noble metals and silicon. These metals deposited on Si form numerous stable chemical compounds at low temperatures and have found applications as Schottky barrier contacts to silicon in VLSI devices. Since the very first phase that nucleates in contact with Si determines the barrier properties, the purpose of our study was to investigate the silicide formation of the near noble metals, Pd and Pt, at very thin thickness of the metal films on amorphous silicon.Films of Pd and Pt in the thickness range of 0.5nm to 20nm were made by room temperature evaporation on 40nm thick amorphous Si films, which were first deposited on 30nm thick amorphous Si3N4 membranes in a window configuration. The deposition rate was 0.1 to 0.5nm/sec and the pressure during deposition was 3 x 10 -7 Torr. The samples were annealed at temperatures in the range from 200° to 650°C in a furnace with helium purified by hot (950°C) Ti particles. Transmission electron microscopy and diffraction techniques were used to evaluate changes in structure and morphology of the phases formed as a function of metal thickness and annealing temperature.
Surface zone-axis patterns
Authors: Eades J. A. , Shannon M. D. , Meichle M. E. 
Published: June 2020

In electron diffraction from crystals, whether it be in reflection or transmission, the intensity of the emergent beams varies in a complex way with the angle that the incident beam makes with the crystal structure. The techniques for displaying this variation of intensity as a function of incident beam orientation have mostly been applied to zone-axis orientations, where the variation is particularly elaborate. The resulting patterns, known as zone-axis patterns or zaps, have become an important part of transmission electron microscopy.There are several techniques for obtaining zaps. The best known is convergent-beam diffraction but they can also be obtained in the form of bend-contour patterns and Tanaka patterns, and by rocking methods.
Laser recording of mass memory data
Authors: Bartolini Robert A. 
Published: June 2020

Optical recording systems capable of information storage and retrieval using a highly focused laser beam as the recording and playback source have been developed to a point where product introduction has begun. The products range from low-data-rate (10-20 Mbits/sec), single disc (1010 to 1011 bits), random access electronic office filing cabinets (augmenting existing word processing units) to high-data-rate (100's of Mbits/sec), multidisc (1013 bits on line “jukeboxes”), random access archival mass memories.The advantages that optical disc recording systems provide are:Very high information density (1010 to 1011 bits per disc have been demonstrated);Very high data rates (up to 50 Mbits/sec in a single channel recorder have been demonstrated);Rapid random access to the data (<<1 sec) has also been demonstrated;The cost of the media has been projected to be 5x10-8 cent/bit;The media have the potential for archival storage (10 years or more) of the data.
Thickness and composition determinations from T.E.M. specimens using both x-ray and backscattered electron data
Authors: Ball M.D. , Lagace H. , Thornton M.C. 
Published: June 2020

The backscattered electron coefficient η for transmission electron microscope specimens depends on both the atomic number Z and the thickness t. Hence for specimens of known atomic number, the thickness can be determined from backscattered electron coefficient measurements. This work describes a simple and convenient method of estimating the thickness and the corrected composition of areas of uncertain atomic number by combining x-ray microanalysis and backscattered electron intensity measurements.The method is best described in terms of the flow chart shown In Figure 1. Having selected a feature of interest, x-ray microanalysis data is recorded and used to estimate the composition. At this stage thickness corrections for absorption and fluorescence are not performed.
Electron microscopy of oxide and sulfide scales on iron and nickel
Authors: Hobbs Linn W. 
Published: June 2020

Corrosion scales formed by oxidation and sulfidation of metals at high temperature have long been the traditional preserve of metallurgists and electrochemists armed with light-optical metallography and gravimetry. It has been only recently that electron microscopical techniques have made a substantial impact on the understanding of scale microstructure and morphological development and on knowledge of extended defect structure accommodating the nonstoichiometry imposed by activity gradients sustained across scales. An important advance was the perfection of techniques for consistently producing transverse sections across scale and substrate (Fig. 1) which reliably preserve both scale/substrate and substrate/gas interfaces.This contribution focuses on several intriguing microstructural features of the ‘simple’ scales NiO, FeO and FeS formed on pure metal substrates, in which the predominant form of mass transport is outward diffusion of metal via inward diffusion of cation vacancies, so that new scale is formed at the scale/gas interface.
A newly developed 200-kV analytical electron microscope
Authors: Tomita T. , Iwatsuki M. , Arai Y. , Ishida Y. , Ibe K. , Kersker M. 
Published: June 2020

In the fields of material science, analysis of ultramicroareas has recently become important to develop new functional materials such as semiconducting compounds and ceramics. A 200 kV electron microscope has been developed for ultramicroarea structural and chemical analysis with a fine electron probe a few nm in diameter in the TEM and STEM modes. The present paper reports some features of the electron microscope.The illumination lens system consists of a four condenser lenses (1st condenser; CL1, 2nd condenser; CL2, condenser mini; CM, and upper objective lens) to change the probe size over a wide range in the TEM mode. Two combination of excitation conditions for pre-aligned illumination lenses controlled by micro-processor is used to get a exact correspondence between the fine structure under high resolution image observation and the area a few nm in diameter under analysis.
Electron microscopic assays of restriction endonuclease cutting, exonuclease digestion, and hybridization
Authors: Hannibal Mark , Varkey Jacob , Beer Michael 
Published: June 2020

Workman and Langmore have recently proposed a procedure for isolating particular chromatin fragments. The method requires restriction endonuclease cutting of the chromatin and a probe, their digestion with two exonucleases which leave complimentary single strand termini and low temperature hybridization of these. We here report simple electron microscopic monitoring of the four reactions involved.Our test material was ϕX-174 RF DNA which is cut once by restriction endonuclease Xho I. The conversion of circles to linear molecules was followed in Kleinschmidt spreads. Plate I shows a circular and a linear DNA molecule. The rate of cutting is shown in Figure 1.After completion of the endonuclease cutting, one portion of the DNA was treated with exonuclease III, an enzyme known to digest the 3' terminals of double helical DNA. Aliquots when examined in the electron microscope reveal a decreasing length of double helix and increasing bushes at the ends.
Lymphoproliferative disorders (LPD) involving lungs: T and B cell subsets within pulmonary infiltrates and in peripheral blood
Authors: Stachura Irene , Dalbow Milton H. , Niemiec Michael J. , Pardo Matias , Singh Gurmukh , Hartsock Robert J. 
Published: June 2020

Lymphoid cells were analyzed within pulmonary infiltrates of six patients with lymphoproliferative disorders involving lungs by immunofluorescence and immunoperoxidase techniques utilizing monoclonal antibodies to cell surface antigens T11 (total T), T4 (inducer/helper T), T8 (cytotoxic/suppressor T) and B1 (B cells) and the antisera against heavy (G,A,M) and light (kappa, lambda) immunoglobulin chains. Three patients had pseudolymphoma, two patients had lymphoma and one patient had lymphomatoid granulomatosis.A mixed population of cells was present in tissue infiltrates from the three patients with pseudolymphoma, IgM-kappa producing cells constituted the main B cell type in one patient. In two patients with lymphoma pattern the infiltrates were composed exclusively of T4+ cells and IgG-lambda B cells predominated slightly in the patient with lymphomatoid granulomatosis.
Transmission Electron Microscopy of the Deformation Structures in Silicon Carbide
Authors: Clarke D.R. 
Published: June 2020

Silicon carbide is, like many other candidate ceramics for high temperature applications, brittle when tested macroscopically. However, little is known about its deformation at a microscopic scale. This contribution reports the observation of limited plasticity and microscopic cracking produced during fracture of silicon carbide.The material used in this work was a dense sub-micron grain size silicon carbide produced by hot pressing with the addition of a small quantity of boron. Disc specimens suitable for examination in a Philips EM 301 microscope were prepared by mechanical grinding and subsequent ion thinning. Deformation was then introduced by the simple expedient of breaking the specimen after mounting it on an electron microscope grid. The material has the cubic structure (β).
The Formation and Growth of Crystal Defects in Nickel-Base Alloys Under Proton Irradiation
Authors: Chen L.J. , Ardell A.J. 
Published: June 2020

The investigation of radiation effects in Ni-base alloys has continued to be of interest to the long range LMFBR program. Several Ni-base alloys (Ni-Al, Ni-Cr, Ni-Ti) have been chosen to investigate the fluence dependence of damage, the influence of structural variables and the effect of temperature under proton irradiation.For this transmission electron microscopy (TEM) study, both samples of about 5 mil. thickness and thin perforated samples have been irradiated with fluences up to 3.6 x 1019/cm2 and beam intensity about 100μA/cm2. The irradiation of thin perforated samples enormously simplifies the specimen preparation routine and augments the quantity of observations while giving useful and semi-quantitative data.
High Temperature Strength and Stability of Oxide Dispersion Hardened Alloys
Authors: Grewal M.S. , Sastri S.A. , Grant N.J. 
Published: June 2020

The creep behavior of oxide dispersed alloys can be described by the following equation:where ε is steady state creep rate, σ applied stress, R gas constant, T temperature in °K, Qc activation energy for creep, n stress exponent, A and n are constants.Two unusual observations in the case of O.D. alloys are that Qc and n take on values that have not been explained satisfactorily. This investigation was undertaken to explain the unusually high strength, high Qc and high stability (high value of n) in the oxide dispersed alloys.
Electron Diffraction of Wet, Unstained, Unfixed Rat Hemoglobin
Authors: Dobbs B. C. , Pangbom W. A. , Parsons D. F. 
Published: June 2020

Electron diffraction provides a method for studying the structure of molecules which are obtainable only as microcrystals, since the scattering amplitudes for electrons are at least 103 greater than for X-rays. Included in this class of molecules are many of biological interest. However, most compounds of biological interest require a hydrated environment to maintain their crystal integrity, and have therefore, not been suitable for high resolution electron diffraction. The development of the hydration stage has given new impetus to the electron diffraction of hydrated crystals as demonstrated with catalase.Sickle cell anemia, a disease which is associated with a hemoglobin that is insoluble in physiological media, provides semi-ordered hemoglobin filaments which may be investigated by electron diffraction. As a first model in investigating such a system, rat hemoglobin, which crystallizes in physioligicaL media (3), has been chosen.
Etching Techniques and the Surface Morphology of the Gunflint Chert
Authors: Johnson A. H. 
Published: June 2020

Samples of the Gunflint Chert (2.0 billion years old), collected near Kakabeca Falls, Ontario by Dr. L. P. Knauth, have yielded several distinct and recurring morphologies when in hydrofluoric acid of varying concentrations for varying lengths of time, and viewed with a scanning electron microscope.The chert is entirely siliceous, with the exception of minor calcareous lenses identified by energy dispersive analysis. Previous studies of the Gunflint Chert have been made using TEM however SEM offers a three dimensional view which greatly aids interpretation.The samples were prepared by fracturing followed by etching in HF for 30 seconds to 48 hours with concentrations varying from .5% to 30%. It appears that the optimum concentration and etch time varies according to the particular morphology one wishes to develop. This is due to the difference in response to HF by the different textures in the rocks.