bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of matrigel on development of A549 lung epithelial cells
Authors: Kress Yvonne , Bloom Barry R. , McDonough Kathleen A. 
Published: June 2020

Extracellular matrix components are known to influence the growth and differentiation of cultured cells, often causing them to behave more like their in vivo counterparts than cells grown on plastic. To develop an in vitro model in which to study the interaction of pathogenic microorganisms with the lung epithelium, we have undertaken a morphological study of the effects of extracellular matrix components on the human lung alveolar epithelial cell line A549. A549 cells were grown for varying amounts of time on plastic; Costar polycarbonate membrane filter inserts; or on Matrigel coated polycarbonate filter inserts. Cells were fixed for 1 h in 2% glutaraldehyde in 0.1 M cacodylate buffer, post-fixed in 1 % OsO4 for 45 min, dehydrated in ascending ethanol, and embedded in Spurr’s resin.A549 cells grown on a plastic slide formed an even monolayer with cells connected by wellformed junctional complexes or separated by interdigitating microvilli. The cytoplasm showed many polyribosomes, rough endoplasmic reticulum, small golgi complexes, mitochondria, occasional lysosomes and bundles of microfilaments.
Chemically induced accumulation of phospholipids in canine organ systems
Authors: Maleeff Beverly E. , Kircher Charles H. , Badger Alison M. , Hart Timothy K. , Bugelski Peter J. 
Published: June 2020

Cationic amphiphilic drugs (CAD) are structurally characterized by their hydrophobic ring structure and hydrophilic side chain. Studies have shown that over 30 CADs with various pharmacological activities have the ability to induce phospholipid-like inclusions in peripheral blood cells and in organs such as lung, liver and spleen. SK&F 105685 is a novel cationic amphiphilic compound with immunomodulatory activity. It induces immune suppressor cell activity in many species. The purpose of this study was to determine if this compound induces cytoplasmic phospholipid inclusions in dogs.Heparinized blood samples were collected from male and female dogs after 14 and 85 days of treatment. Buffy coats were prepared and fixed with 2.5% glutaraldehyde - 2.0% paraformaldehyde with 50 μM CaCl2 in 0.1 M cacodylate buffer, pH 7.2. The pellets were processed to epoxy resin. Tissues from all organs were collected at necropsy in buffered formalin following 30 or 90 days of treatment, and processed for histopathologic evaluation.
Effects of low-temperature heating on the morphology of birch wood
Authors: Fisher Robert M. , Reine Barbara A. 
Published: June 2020

The effects of heating wood have been studied for many years with much of the work focused on the curing, ignition, extraction of gaseous and liquid by-products, production of charcoal and, of course, high temperature oxidation, i.e. combustion. Research techniques include bulk weight-loss studies or differential gravimetric analysis (DTA), analyses of the evolution of a wide variety of C-O-H organic compounds by gas chromatography and mass spectroscopy, observing critical times and temperatures for piloted and smoldering ignition, analyses of heat energy absorption and release using Differential Thermal Analysis (DTA) and measurement of the caloric value of firewood and charcoal. Optical microscopy has been used in support of these studies but surprisingly little electron microscopy has been carried out.The stimulus for this research was curiosity about structural changes during long term heating of wood that increase its' susceptibility to spontaneous, i.e., smoldering combustion. The literature on fire origin investigations contains numerous references to cases where fires were believed to have resulted from spontaneous ignition of structural wood members after years of exposure to steam heating pipes.
Strained-layer Van Der Waals epitaxy in a Langmuir-Blodgett film
Authors: Viswanathan Ravi 
Published: June 2020

Langmuir-Blodgett (LB) films are layered structures of amphiphilic molecules which are assembled by successive deposition on a solid substrate from a monolayer at the air water interface. Most of the potential applications of LB films (molecular electronics, cell membrane models, biosensors) are based on the premise of perfect molecular layering and orientation. The technique of atomic force microscopy (AFM), which probes only the outermost layer of the film, has opened up the study of the surfaces of these films which occupy a unique position at the intersection of surface science and complex fluids. We show here that the growth of lead stearate (PbSt) LB films on mica substrates proceeds by a new type of epitaxy which we call “strained layer van der Waals epitaxy” because it represents a compromise between the mechanisms of strained-layer epitaxy and van der Waals epitaxy.The PbSt films were prepared with the standard Langmuir-Blodgett vertical dipping method and imaged with the AFM in air at ambient temperature.
Tacky dot arrays for ordered particle mounting
Authors: Cairncross Allan , Flaherty David M. , Klabunde Ulrich 
Published: June 2020

We describe for the first time a rapid way to mount particles on regularly spaced centers for microscopic examination. This innovative method mounts particles in ordered arrays rather than the random chaos of usual methods and therefore simplifies particle examination, identification and analysis. Advantages include the ability to easily mount single particles in controlled patterns and known locations, to mount tight clusters of 2 or more particles per center (Fig. 3); to repeatedly mount the same pattern/number of particles; to mount particles in unusual orientations (Fig. 5, 6) and to easily get the average weight of single particles. Examples of applications include mounting and examination of ores (Fig. 1), pollens (Fig. 2, 3), milled products, seeds (Fig. 4) and crystalline products(Fig. 5, 6).The mounting medium consists of a pattern of fine adhesive centers typically on 1 by 3 inch glass slides or on clear plastic film that is easily cut to any size or shape.
Nanometer-resolution Auger electron spectroscopy and microscopy of small particles
Authors: LIU JINGYUE 
Published: June 2020

Small metal particles have peculiar physical and chemical properties and they are especially important in catalysis. A detailed understanding of catalytic processes requires knowledge of both the microstructure and the microchemistry of the catalyst system. Although nanometer scale surface topography of supported catalysts can be studied with secondary electron (SE) signals, a chemically specific and surface sensitive signal such as Auger electrons must be used to extract compositional information about the surface species. Auger electron (AE) spectroscopy (AES) and scanning Auger microscopy (SAM) have been widely used for surface and catalyst characterization. In order to observe the active phases (small particles) of supported catalysts, it is necessary, however, to have nanometer scale resolution in SAM images.With significant improvement in detection efficiency of low energy secondary electrons by employing magnetic parallelizers in our UHV scanning transmission electron microscope (STEM), known as MIDAS (a Microscope for Imaging, Diffraction and Analysis of Surfaces), a spatial resolution of approximately 3 nm in SAM images has been achieved on bulk samples.
Triply-periodic nanostructures in surfactant, block copolymer, and biomembrane systems, and simulation of TEMs
Authors: Anderson David M. , Landh Tomas 
Published: June 2020

First discovered in surfactant-water liquid crystalline systems, so-called ‘bicontinuous cubic phases’ have the property that hydropnilic and lipophilic microdomains form interpenetrating networks conforming to cubic lattices on the scale of nanometers. Later these same structures were found in star diblock copolymers, where the simultaneous continuity of elastomeric and glassy domains gives rise to unique physical properties. Today it is well-established that the symmetry and topology of such a morphology are accurately described by one of several triply-periodic minimal surfaces, and that the interface between hydrophilic and hydrophobic, or immiscible polymer, domains is described by a triply-periodic surface of constant, nonzero mean curvature. One example of such a dividing surface is shown in figure 5.The study of these structures has become of increasing importance in the past five years for two reasons:1)Bicontinuous cubic phase liquid crystals are now being polymerized to create microporous materials with monodispersed pores and readily functionalizable porewalls; figure 3 shows a TEM from a polymerized surfactant / methylmethacrylate / water cubic phase; and2)Compelling evidence has been found that these same morphologies describe biomembrane systems in a wide range of cells.
Morphology of Acid-Cleaned Heat-Treated MgO (100) Surfaces
Authors: King Simon , Barry Carter C. 
Published: June 2020

The widespread use of the (100) MgO surface as a substrate for the deposition particularly of high-Tc super-conductors, and a wide variety of other materials such as titania, has provoked considerable interest in the morphology of the surfaces employed. In the above studies, (100) oriented MgO specimens have generally been prepared according to the method of Norton et al, in which foils are cleaned in acid, with the active ingredient being aqua-regia, after perforation by ion-milling and before a heat treatment in air, typically for 10-15 mins at 1350 °C. The surface morphology of specimens prepared in this manner is explored in this paper.Many of the features common to the aqua-regia cleaned and heat-treated thin-films are shown in the (100) zone-axis bright-field (BF) image of fig 1(a). The general morphology of these foils includes a high density of holes within the thinnest regions, whilst pores are in evidence in thicker areas.
Electron holography with a CM30-FEG-special-Tübingen Microscope
Authors: Lichte Hannes 
Published: June 2020

Electron holography offers the advantage over conventional microscopy that full use of the object information can be made especially if numerical reconstruction is applied: By coherent optical coupling of a computer to the electron microscope, the electron object wave is completely available for a very flexible wave optical analysis. For example, besides the correction of the coherent aberrations (e.g. spherical aberration, defocus and astigmatism) and the unique accessability of both amplitude and phase of the object wave in real space and in Fourier space, techniques like nanodiffraction or Selective Imaging can be used to improve our knowledge about the object structure at atomic dimensions.However, there are limits imposed on this scheme by the restrictions given by todays technology for the two steps of data acqusition and processing, i.e taking the hologram and reconstructing the wave.First, the information collected in a hologram is limited by incoherent effects.
HRTEM Image of Twin Structure in Nanocrystalline Platinum
Authors: Lin Hong-Ming , Hsu Chi-Ming , Huang Ching-Shung , Lay Ming-Shyong , Lee Pee-Yew 
Published: June 2020

This paper presents recent result on the observation of microstructure of nanocrystalline platinum. Nanocrystalline powders of Pt are made by gas condensation method, and examined by using TEM and HRTEM. Twin structure is found first within the individual particle of as evaporated nanophase Pt particles which form twin during the nucleation and growth of particle. Twin also appears while neck growth take place during the sintering of as evaporated pt with Al2O3. The formation of these twins during sintering was due to the fact that the neck growth will induce a tensile stress which is high enough to pull the nanocrystalline powders to form twin structure. Twin plane of nanophase sintering Pt powder was identified by using the Fourier transformation as {111} plane. It is the same as usually found in fcc bulk materials.The pure nanocrystalline Pt particles with a diameter less than 100 nm had been produced by the gas evaporation in helium atmosphere.
User-friendly field emission
Authors: Crewe Albert V. , Clayton Deborah L. , Crewe David A. , Moscicka Katarzyna 
Published: June 2020

We introduced the field emission source into electron microscopy twenty five years ago but in spite of the obvious advantages of such a source it was not an instant success. In fact it is only in recent years that the use of field emission has become significant, and even now it is only for high performance, high cost instruments.The reasons for customer resistance are not hard to find. Firs t there is the need for a UHV system, a necessity which brings with it a significant increase in cost and also the need for new expertise and training since UHV systems use different hardware and different maintenance procedures.Next there is the need for knowledge and experience with field emission and its peculiar characteristics. Tips need to be “flashed” and the operator needs to be able to recognize the symptoms which signal that need.
Image processing to delineate defect structures in HREM images of vapor-deposited thin films
Authors: Fisher R.M. , Duan J.Z. , Hetherington Crispin J. , Fowler Norman 
Published: June 2020

The resistance of deposited thin films to cracking or delamination from substrates during production or service, crucial to the long term reliability of IC devices, is under study as part of a broad program on interfacial bonding and adhesion. Chromium films, of particular interest because of their widespread use in microelectronics, are especially prone to mechanical failure due to the high residual stresses that are generally present and their low fracture toughness. Transmission and scanning electron microscopy are being used to define the columnar grain structure and failure modes and x-ray diffraction is being employed to determine the nature of through-thickness stress gradients that occur in such films.The intrinsic stress, as distinguished from the extrinsic stress caused by differential contraction between film and substrate during cooling from the deposition temperature, results from the presence of vacancies and diffuse “voids” trapped between the columns during deposition. Transmission electron microscopy of plan-view and cross-sections is being used in efforts to observe and define the structure of the inter-columnar regions.
Superconductivities and structure modulations in Tl-Ba-Ca-Cu-O oxides
Authors: Iijima Sumio 
Published: June 2020

Charge carrier sources for the superconductivities of high Tc oxides have been sought by various techniques. The role of lattice defects in the superconductivity, and structural defects which are common in these oxides, were investigated by electron microscopists. In this paper, microstructures on TBCCO oxide crystals, in particular, superlattice modulations in the 2201 phase, and Y-doped 2212 phases which are prepared under various growth conditions, are presented. All specimens were prepared in the standard sintering method.In contrast with the 2212 and 2223 compounds, the 2201 compounds showed a wide range of Tc values. Their variations were found to be strongly affected by oxygen content.This was concluded from the fact that the nonsuperconductive specimen became conductive by quenching after heating in O2 atmosphere at 400°C. This was further confirmed when the superconductivity vanished by annealing. It was also demonstrated that crystal symmetries of the compounds, orthorhombic and tetragona1 are not directly related to the superconductivity as was proposed by Hewat et al. The orthorhombic structures are obtained at preparation temperatures above 840°C. It was also found that the Tc value increases linearly with an increase in the c-axis length which is independent of crystal structures.
The analysis of “Gels” in polymer films
Authors: Brown G. M. , Brown D. F. , Butler J. H. 
Published: June 2020

The term “gel”, in the jargon of the plastics film industry, may refer to any inclusion that produces a visible artifact in a polymeric film. Although they can occur in any plastic product, gels are a principle concern in films where they detract from the cosmetic appearance of the product and may compromise its mechanical strength by acting as local stress concentrators. Many film gels are small spheres or ellipsoids less than one millimeter in diameter whereas other gels are fusiform-shaped and may reach several centimeters in length. The actual composition of gel inclusions may vary from miscellaneous inorganics (i.e. glass and mineral particles) and processing additives to heavily oxidized, charred or crosslinked polymer. The most commonly observed gels contain polymer differing from the bulk of the sample in its melt viscosity, density or molecular weight.Polymeric gels are a special concern in polyethylene films. Over the years and with the examination of a variety of these samples three predominant polymeric species have been observed: density gels which have different crystallinity than the film; melt-index gels in which the molecular weight is different than the film and crosslinked gels which are comprised of crosslinked polyethylene.
Surface oxygen artifacts on aluminum nitride
Authors: Callahan Daniel L. 
Published: June 2020

Aluminum nitride (AlN)is an increasingly important electronic ceramic with oxygen as an important bulk impurity. Quantitative microanalysis of oxygen to determine its precise distribution is a necessary step in characterization of the ceramic that may be complicated due to surface oxidation. AlN is thermodynamically unstable compared to the oxide (Al2O3) at room temperature in the presence of environmental oxygen or water and may thus be expected to form a thin, possibly passive oxide film similar to the oxide layer of pure aluminum metal. Such an oxide layer has been used to explain anomalies in oxygen quantification in AlN by neutron activation methods [1] but reflecteion high energy electron diffraction studies [2] failed to reveal either crystalline or amorphous oxide phases forming at room temperature.Electron diffraction techniques in the transmission electron microscope were used to examine thin AlN sections for possiblecrystalline surface layers. A ceramic AlN sample was prepared using conventional techniques for the preparation of thin foils with final thinning accomplished by ion milling.
Microscopy of porous ceramics
Authors: Kerch H. M. , Gerhardt R. A. 
Published: June 2020

Highly porous ceramics are employed in a variety of engineering applications due to their unique mechanical, optical, and electrical characteristics. In order to achieve proper design and function, information about the pore structure must be obtained. Parameters of importance include pore size, pore volume, and size distribution, as well as pore texture and geometry. A quantitative determination of these features for high porosity materials by a microscopic technique is usually not done because artifacts introduced by either the sample preparation method or the image forming process of the microscope make interpretation difficult.Scanning electron microscopy for both fractured and polished surfaces has been utilized extensively for examining pore structures. However, there is uncertainty in distinguishing between topography and pores for the fractured specimen and sample pullout obscures the true morphology for samples that are polished. In addition, very small pores (nm range) cannot be resolved in the S.E.M. On the other hand, T.E.M. has better resolution but the specimen preparation methods involved such as powder dispersion, ion milling, and chemical etching may incur problems ranging from preferential widening of pores to partial or complete destruction of the pore network.
Microdiffraction and convergent-beam diffraction from surfaces
Authors: Eades J. A. 
Published: June 2020

Microdiffraction from surfaces at near grazing incidence is an important method of surface characterization. It is very much akin to RHEED (reflection high-energy electron diffraction) except that in RHEED a large area of sample (∼ 1 mm2) contributes to the diffraction. In this respect the relationship between RHEED and surface microdiffraction is analogous to that between selected-area diffraction and microdiffraction in transmission. In addition RHEED systems usually have no post-specimen lenses and therefore operate at a fixed camera length.Surface microdiffraction can contribute important information for the characterization of surfaces but there are some important factors that make it more complex than in the case of convergent-beam diffraction in transmission.At grazing incidence, even with high-energy electrons, refraction at the surface is important -whereas in transmission (at near-normal incidence) it may be neglected.
HREM observation of NiO growth on submicron spheres of pure nickel
Authors: Teng C.M. , Kelly T.F. , Zhang J.P. , Lin H.M. , Kim Y.W. 
Published: June 2020

Spherical submicron particles of materials produced by electrohydrodynamic (EHD) atomization have been used to study a variety of materials processes including nucleation of alternative crystallization phases in iron-nickel and nickel-chromium alloys, amorphous solidification in submicron droplets of pure metals, and quasi-crystal formation in nickel-chromium alloys. Some experiments on pure nickel, nickel oxide single crystals, the nickel/nickel(II) oxide interface, and grain boundaries in nickel monoxide have been performed by STEM. For these latter studies, HREM is the most direct approach to obtain particle crystal structures at the atomic level. Grain boundaries in nickel oxide have also been investigated by HREM. In this paper, we present preliminary results of HREM observations of NiO growth on submicron spheres of pure nickel.Small particles of pure nickel were prepared by EHD atomization. For the study of pure nickel, 0.5 mm diameter pure nickel wire (99.9975%) is sprayed directly in the EHD process. The liquid droplets solidify in free-flight through a vacuum chamber operated at about 10-7 torr.
Formation and stability of {113} defects in oxygen implanted silicon-on-insulator material
Authors: Ravi T.S. , Jung C.O. , Burke D.E. , Krause S.J. 
Published: June 2020

High dose oxygen implantation into Si (SIMOX – Separation by Implantation of Oxygen) is a viable technique for producing silicon-on-insulator structures. The {113} defect was first observed in SIMOX by van Ommen. It has received considerable study in bulk Si. Bergholz et al. proposed that {113} defects are coesite, a high pressure monoclinic phase of silica, and are a possible precursor to amorphous silicon oxide. Recently Bourrel proposed a self-interstitial model for the formation of hexagonal silicon in the {113} planes in the diamond cubic lattice which was an extension of Tan's model and suggested that oxygen is generally not required for the creation of {113} defects. In this paper we have examined the formation and stability of {113} defects in as-implanted and annealed SIMOX.The first set of samples studied was implanted to 2.4×1018 cm-2 at 200 keV from 400°C to 600°C. The second set was implanted at 150 keV to 2.0×1018 cm-2 at 500°C. Five equivalent parts of the wafer were annealed from 650°C to 1050°C in steps of l00°C for two hours in Ar. Cross-section samples were made by gluing, grinding, dimpling and ion milling of the wafer chips.