bluuebunny/crossref_metadata_2025 huggingface dataset:
Imaging Phospholipid Arrangement in Pultonary Surfactant Using Atomic Force Microscopy
Authors: Nag K , Possmayer F , Petersen N O , Hearn S A
Published: July 2020

Lung surfactant stabilizes the pulmonary air-water interface, by enriching this interface with films of amphipathic phospholipids. These films reduce the surface tension of the air-water interface to very low values (∼ 1 mN/m) at end expiration and prevents alveolar collapse. Surfactant contains mainly phospholipids (90%), and small amounts of associated proteins. Among the phospholipids, saturated dipalmitoylphosphatidylcholine (DPPC) and monounsaturated phosphatidylcholine are the main surfactant components, although significant amounts of other lipids are also present (1). DPPC is the only component of surfactant which exists in gel phase at physiological temperature, films of which can reduce the air-water surface tension to low values. DPPC films can undergo a fluid to gel transition with increase in the molecular packing leading to superstructures or domains (2). However it is not clear how the molecules of surfactant pack at the air-water interface to form highly compact films, and if DPPC phase segregate in such films.
Examination of Frozen, Hydrated Mites Using Low Temperature Field Emission Scanning Electron Microscopy
Authors: Ochoa Ronald , Erbe Eric F , Pettis Jeffery S , Wergin William P
Published: July 2020

Mites, the second largest arthropod group after insects, occupy every conceivable terrestrial and aquatic habitat in our environment. They feed on plants, infest food products such as meat, cheese and grains, parasitize invertebrates and vertebrates, and transmit fungal, bacterial, rickettsial and viral diseases. Estimates indicate that as many as 1,000,000 species of mites may exist; however, partly because of their microscopic size, only about 40,000 species have been described and classified. During the last 30 years, researchers have increasingly utilized the greater magnification and depth of field available in a conventional scanning electron microscope (SEM) to supplement descriptions of mites that were historically based on light microscopic observations. In addition, this technique provided a better understanding of the relative positions and functionality of organs and improved attempts to elucidate their biology. However, before mites can be imaged with a conventional SEM, they are typically chemically fixed, dehydrated and/or thoroughly dried.
Light and Electron Microscopic Examination of the Parasitic Dinoflagellate Haplozoon
Authors: Landers Stephen C
Published: July 2020

The parasitic dinoflagellate Haplozoon is found in the intestine of marine polychaetes. It is composed of a chain of cells that hang from the intestinal wall into the lumen, and releases daughter cells from the posterior end of the chain which leave the host and reinfect other polychaetes. Few studies exist in the recent literature regarding Haplozoon and it has not been reported from the Gulf Coast of the United States. This study reports the genus Haplozoon from the maldanid polychaete Axiothella mucosa in St. Andrew Bay, Florida, and examines the structure of the organism by light and electron microscopy.

Axiothella mucosa was collected in St. Andrew Bay, Florida and maintained in seawater at the Troy State University campus. Haplozoon spp. was prepared for whole mounts by smearing minced setigers of the worms onto a slide with a drop of seawater.
The Technical Aspects for Studying Morphology of Purified Lacrimal Gland Acinar Cells Cultured on Matrigel Rafts: A New Model System for Studying Lacrimal Physiology
Authors: Pidgeon Mike , Schechter, Ph.D Joel , Chang, M.S. Natalie , Chang Donald , Trousdale, Ph.D. Melvin , Stevenson Doug
Published: July 2020

Objective: To demonstrate the quality of a new model which gives a close representation of the in situ gland for studying functional characteristics of lacrimal acinar cells. A method has been long sought which would serve as a good in-situ model for studying functional attributes of lacrimal acinar cells. Previous methods used cell plates coated with Matrigel as a growth interface for lacrimal acinar cells.

Two problems associated with this method are: cell cultures seeded this way provided a restrictive, planar growth interface, and the inability to maintain cultures beyond seven days, due in part to a lack of proliferation. A modification of recent methods (Guo et al., 1998) was implemented. The cell preparations were coated with a Hepato Stim® Medium (supplemented with EGF, DHT) and Matrigel. The medium is an extracellular matrix enriched solubilized preparation developed from the basement membranes of the Englebreth-Holm-Swarm mouse sarcoma line.
Localization of Z-RNA in Normal Lens Epithelium: Middle Fibers
Authors: Gagna CE , Kuo HR , Schulz R , Cordova R , Crippen G , Lambert WC
Published: July 2020

The goal of this project was to analyze the cellular localization of Z-RNA, within middle fibers (MF) of the adult dog ocular lens (1.5 yr) (Fig. 1), using anti-Z-RNA IgG polyclonal antibodies. B-DNA can adopt the left-handed Z-DNA conformation in vitro (1). Right-handed A-RNA can be transformed into left-handed Z-RNA (2). Z-RNA has been studied in cultured cells (3). Evidence supports the presence of Z-DNA in vivo (1). Removal of DNA binding proteins by fixatives can initiate supercoiling which stabilizes Z-DNA sequences (1).

Anti-Z-RNA polyclonal antibody probes were developed in rabbits immunized with multiple injections of Z-RNA: Br-poly[ribosomal(G-C)]. Regarding immunohistochemistry, lens tissues were fixed in Carnoy's, embedded in paraffin and sectioned (2.5 μm) (Fig. 2). Computerized image analysis was performed using a Leitz DM-RB microscope and Leica Quantiment 500 + image analyzer.
Detection of Iodine by Scanning Electron Microscopy(SEM) and Energy Dispersive Spectroscopy(EDS) Following Contact with an Iodine Releasing Coating
Authors: Lyden LM , Zaruba KS , Gysbers JE , Kato KH
Published: July 2020

The detection and localization of iodine in biological tissues have traditionally presented problems associated with sample preparation of soluble elements. Standard sample preparation for biological tissue involves methods which solubilize or extract iodine.Furthermore, analytical methods for detection of elements typically have been studied in smooth flat materials. We describe two methods using frozen pig skin for detecting iodine in tissue, creating digital color maps of iodine concentrations in cross sections of pig skin, and visualizing flow properties of an iodine-releasing coating at skin surfaces.

Biological samples were analyzed with the Philips XL30 SEM integrated EDAX systems using peak identification and digital color mapping software packages. Iodine-releasing coatings were applied to pig skin explants and processed by freeze-drying. The stratum corneum and hair follicle regions of pig skin remained undistorted and identifiable after dissection and processing. Iodine was detected in the coating, in the stratum corneum, and in the tissue surrounding hair follicles (Fig. 1).
Adaptation Of Environmental Transmission Electron Microscopy (ETEM) And Electron Energy Loss Spectrometry (EELS) For Studies Of Microbiologically Influenced Corrosion
Authors: Pope Robert K , Daulton Tyrone L , Ray Richard I , Little Brenda J
Published: July 2020

Microbiologically influenced corrosion (MIC) is of wide concern in marine and non-marine environments. Biofilms and corrosion products associated with microorganisms cause numerous problems in aqueous environments, such as increased fluid frictional resistance, reduced heat transfer, and many types of corrosion, all of which can lead to failure of materials. Corrosion of metals has been extensively examined using TEM, but examination of MIC with TEM has only just begun (Blunn, 1986; Chio, 1996). Previous studies examining microbial colonization of copper surfaces and distribution throughout corrosion products demonstrate copper immobilization by bacterial biofilms (Blunn, 1987). In the current study, Pseudomonasputida attachment to corroding iron particles was examined in a sealed environmental cell in a JEOL 3010 scanning transmission electron microscope (STEM).

Iron filings were produced from carbon steel (C1010) using 600 grit sandpaper, collected with a teflon coated magnet, degreased in acetone and sterilized in ethanol. Filings were incubated in distilled water until corrosion was visible under a dissecting microscope.
Microscopy and Microanalysis of Plutonium Metal, Alloys and Oxides or the Problem With Pu
Authors: Lakis Rollin E , Storey Bradford G , Davis Charles C
Published: July 2020

Plutonium (Pu), with an atomic number of 94, is the highest atomic number naturally occurring element on Earth. It is formed when naturally occurring Uranium 238 captures a neutron that can be created by spontaneous fission and alphaneutron reactions. The natural abundance of terrestrial Pu is very small; its concentration is about one part in 10 of the uranium present in naturally occurring uranium ores. The first man-made plutonium was produced at the University of California cyclotron and identified on February 23, 1941. Just a few months after the first Pu was produced it became clear how metallurgically complex this material is. Plutonium is known to have six allotropes (crystalline forms) at atmospheric pressure, between room temperature and 640°C, the melting point of the pure metal. This is the largest number of allotropes known for any element.
Useful Lead and Bismuth Standards for Quantitative Electron Probe Microanalysis
Authors: Marinenko R B , Windsor E S
Published: July 2020

Lead and bismuth standards for quantitative electron probe microanalysis have always been a problem due to mechanical polishing and surface oxidation upon atmospheric exposure. Some Pb and Bi compounds, such as the selenides and tellurides, can be obtained commercially as solid pieces that are large enough to be mounted as useful standards, but they can also form non-stoichiometric solid solutions. This paper is a description of the initial work done on the testing of some selenides and tellurides to evaluate their usefulness as standards for quantitation. In addition, improved procedures for preparing the Pb and Bi element and compound specimens are being used to reduce surface oxidation. Primarily Pb samples were evaluated here, but the project will be extended in the future to include more Bi materials.

Experimental

Most specimens were mounted in silver epoxy in multi-element mounts that were repolished according to the description below. Additional specimens of PbTe, PbSe, and Pb were mounted in epoxy for this work.
HARECX Measurements of Electron Channeling Effects on Quantitative AEM-Based XEDS
Authors: Zaluzec Nestor J
Published: July 2020

It has been long known that orientation effects in crystalline materials can influence characteristic x-ray emission and microanalysis. Most of the recent studies have concentrated upon using the phenomenon to perform site specific distributions of impurity elements in ordered compounds using the ALCHEMI methodology. For the most part, it has been asserted that increasing the parameters of thickness, orientation and beam convergence effectively averages out these effects. Using High Angular Resolution Electron Channeling X-ray Spectroscopy (HARECXS) we have carefully measured the phenomenon in a number of ordered systems and find that it must be considered in many cases.

All experimental measurements presented here were conducted on a Philips EM 420T analytical electron microscope. The instrument was operated in the TEM mode, at 120 kV using a LaB6 electron source. The characteristic x-ray emission was measured using an ED AX ultra thin window Si(Li) detector having a FWHM of ∼ 145 eV at Mn Ka.
Coupling Automated Electron Backscatter Diffraction with Transmission Electron and Atomic Force Microscopies
Authors: Schwartz AJ , Kumar M , Bedrossian PJ , King WE
Published: July 2020

Grain boundary network engineering is an emerging field that encompasses the concept that modifications to conventional thermomechanical processing can result in improved properties through the disruption of the random grain boundary network. Various researchers have reported a correlation between the grain boundary character distribution (defined as the fractions of “special” and “random” grain boundaries) and dramatic improvements in properties such as corrosion and stress corrosion cracking, creep, etc. While much early work in the field emphasized property improvements, the opportunity now exists to elucidate the underlying materials science of grain boundary network engineering. Recent investigations at LLNL have coupled automated electron backscatter diffraction (EBSD) with transmission electron microscopy (TEM)5 and atomic force microscopy (AFM) to elucidate these fundamental mechanisms.

An example of the coupling of TEM and EBSD is given in Figures 1-3. The EBSD image in Figure 1 reveals “segmentation” of boundaries from special to random and random to special and low angle grain boundaries in some grains, but not others, resulting from the 15% compression of an Inconel 600 polycrystal.
Use of Electron Backscatter Diffraction Technique in Characterization of 6XXX Aluminum Alloy Extrusions
Authors: Claves Steven R , Misiolek Wojciech Z , Van Geertruyden William H , Williams David B
Published: July 2020

Electron Backscattering Diffraction (EBSD) is an important tool for analyzing the crystal grain orientation of a microstructure and can be used to formulate conclusions about microtexture, texture determined from individual grains. This technique has been used to study a 6xxx series aluminum alloy's response to the deformation of the extrusion process. Extrusion is the process by which a billet of material is forced, under high pressure, through a die. The material undergoes a significant decrease in cross sectional area, and is formed into a shape equivalent to the geometry of the die orifice. Different bearing lands are shown in shown in Figure 1. These surfaces form the part, and are designed to control the metal flow making it uniform through the die, thus yielding good mechanical properties. This research was focused on the resultant microstructure. The shaded regions of Figure 2 show the two surface regions where EBSD measurements were taken.
TEM & Computer Analysis of Crystallographic Orientation Ratio in [1120]-Co Films on [002]-Cr Films Grown on Mechanically Textured Substrates
Authors: MoberlyChan Warren J , Dorsey P , He L , Zhang M , Lairson B , Lu M
Published: July 2020

Circumferential mechanical texture (scratches) of hard drive substrates has improved head/media tribology; however, it has also been advantageous to the development of OR (Orientation Ratio) for longitudinal media. The magnetic dipoles prefer to circumferentially align with texture, which matches the direction heads read/write. The corrugated nature of films sputtered on fine texture scratches leads to an anisotropic stress state in the films, especially for those deposited at temperatures above ambient; and OR has been attributed to this anisotropic stress. A review article discusses possible causes of the OR such as: self-shadowing due to the texture lines during deposition, circumferential c-axis alignment, shape anisotropy of media grains, and magnetostrictive effects. Another work listed two requirements for OR: <> Co crystallographic growth texture in addition to circumferential texture scratches. The same study considered frequencies and depths of the texture scratches, and concluded that OR increased as the ratio of depth/frequency increased, rather than just as a function of Ra alone.
Alpha 1 Integrin and Collagen Type III in C2C12 Cell Lines
Authors: DiLullo C , Malsbury J , Mattioli P M
Published: July 2020

In nascent cultured primary chick skeletal myocytes, a l integrin is observed to have a punctate distribution. As early as day 3 in culture, however, it can be found to reorganize into periodic doublet bands. Subsequent to a l integrin reorganization, collagen type III has been found to colocalize with these periodic α l integrin bands. The coordinated appearance of these two proteins is suggestive of a possible regulatory role for one or both proteins in muscle development.

To ascertain whether this same αl integrin/collagen type III reorganization occurs in muscle cell lines, differentiating myocytes from the C2C12 cell line were examined for the temporal appearance and localization of both proteins. Cultured C2C12 cells were immunofluorescently labeled with antibodies to al integrin, collagen type III and other muscle specific proteins on days 1, 3, 6, 9 and 11 after growth medium was replaced with differentiation medium.
Single Molecule Manipulation and Sensing with the Atomic Force Microscope
Authors: Lindsay SM , Leuba S H , Zlatanova J , Karymov M A , Bash R , Liu Y-Z , Lohr D , Harrington R E , Cui XD , Zarate X , Perez E , Moore A , Moore TA , Gust D , Sankey OF , Thomfor J
Published: July 2020

The atomic force microscope (AFM) can be used both to manipulate molecules and to make measurements on individual molecules. Here, we describe manipulation of chromatin constructs as an example of the first type of measurement, and electronic measurements on single molecules as an example of the second type.

An AFM was used to both image and stretch single synthetic chromatin fibers consisting of twelve core nucleosomes with no linker histones. Peaks in the force-curves are attributed to sequential detachment of nucleosomes from the glass support (Figure 1). The short distances between peaks and reversibility of the pulling process show that the nucleosomes remain intact even at tensions on the order of 350 picoNewtons (pN). This is more than an order of magnitude larger than the force required to de-spool histone octamers from the nucleosomal DNA in laser optical tweezer measurements made with longer molecules, suggesting that loading rates and sample size are important factors in determining the force required to break inter-molecular bonds.
Elucidating Nature's Secrets for Creating Extraordinary Biomaterials: How far Have We Come?
Authors: Smith Bettye L , Viani Mario , Thompson James , Hansma Paul K
Published: July 2020

Nature produces exquisite structures under ambient conditions using raw materials found in its immediate environment. Examples of naturally resilient materials seem nearly infinite and include (but not limited to) strong composites like seashells and tough fibers like spider dragline silk, which has a breakage energy per unit weight two orders of magnitude greater than high tensile steel.

These natural processes and the resulting materials are ultimately biodegradable and Eco-friendly. Scientists have been interested in nature's designs and processes for hundreds of years. The result of these studies has led to many unique synthetic materials such as KEVLAR™, styrofoam, PLEXIGLAS™, etc. Unfortunately, our “man-made” materials are usually produced under harsh conditions such as high temperatures or under vacuum. Rarely are these processes and the resulting products environmentally friendly.

In order to mimic nature's designs, researchers have attempted to understand its basic mechanisms for making these resilient materials by studying the starting materials that nature produces.
Loading-Rate Dependent Cell Injury: A Design Criterion for Engineered Tissue Constructs
Authors: Barbee Kenneth A
Published: July 2020

Vascular endothelial cells experience a wide range of mechanical stimuli in vivo, including dynamic stretching and time-varying shear stress due to pulsatile blood flow. Under physiologic conditions, these hemodynamic forces constitute an important component of the cells' environment and are necessary for the normal maintenance of the structure and function of the vessel wall. Implantation of artificial vascular graft materials can significantly alter the mechanical environment of the cell. Furthermore, an important design criterion for engineered tissue constructs is the production of a mechanical environment that, ideally, stimulates normal growth and structural adaptation and. At least, avoids extremes in mechanical loading that might cause cellular trauma. In this paper, we investigate the mechanical loading conditions associated with normal and pathological mechanotransduction and cellular injury with an emphasis on the loading rate dependence of the cellular responses.

A custom designed cone-and-plate device] allows arbitrary cone velocity waveforms to be generated.
Phase-Separated Morphologies in Poly(Psuedo Amino Acid)-PEG Blends and Copolymers for Tissue-Scaffolding Applications
Authors: Prayoonthong P , Taylor J , Libera M , Jaffe M , Kohn J
Published: July 2020

Central to the successful advance of tissue engineering (e.g. 1, 2) is the development of highly engineered materials which trigger particular body responses to regenerate specific tissue or sets of tissue. Such properties as hydrophilicity, hydrolytic susceptibility, and protein-recognition behavior are critical to the success of tissue scaffolds. Poly(ethylene glycol) [PEG] is often introduced into scaffold polymers to tune hydrolytically controlled properties. Relatively little is known about the local morphology and nature of phase separation in these systems, however. This research studies the development of phase-separated morphology in blends and randommultiblock copolymers of a tyrosine-based poly(psuedo amino acid) [poly(DTE carbonate)] and PEG 1000 (fig. 1). This system exhibits attractive biocompatability, strength and modulus, and resorption behavior which can be controlled by main-chain and pendant-chain chemistries (3, 4).

The nature of phase separation was studied by bright-field TEM (Philips CM30 ST; CM20 FEG TEM/STEM) using solvent-cast thin films.
New Applications of Electron Microscopy in Pharmaceuticals: Crystallinity Assessment and Polymorph Determination
Authors: Li Z G , Liang L , Harlow R L , Foris C M , Olson R E , Sielecki T M , Liu J , Vickery R D , Maurin M B
Published: July 2020

Recently, transmission electron microscopy has been used in crystallinity assessments and unit cell parameter/polymorph determinations in solid drug substances [1,2]. Lumaxis™ (roxifiban) is a glycoprotein nb/ffla (GPHb/HIa) antagonist discovered recently at The DuPont Pharmaceuticals Company [3] currently undergoing clinical evaluation for the treatment of thrombotic disorders. Lumaxis™ is converted in vivo to a zwitterionic active metabolite, XV459. As reported here, we have assessed by electron microscopy and x-ray diffraction the crystallinity of XP280, the benzenesulfonate salt of XV459, and determined the unit cell parameters of SC877, the methanesulfonate salt of the methyl ester of XV459.

Crystallinity assessment. Partial or complete transformation of crystalline phases into amorphous phases can occur during production processes that may ultimately affect the activity associated with various batches of a drug [4, 5]. Whether desired or not, the amorphous content of any drug substance is thus an important issue for the pharmaceutical industry.
Correlative Neutron Activation and TEM to Determine the Uptake Mechanism and Distribution of Orally Administered Colloidal Gold Nanoparticles
Authors: Hillyer JF , Albrecht RM
Published: July 2020

The uptake of insoluble, particulate matter through the digestive tract occurs in low quantities, and the pathway and amount of particle uptake is size dependent. Previous studies have shown that the uptake of nanoparticles occurs mainly through the Peyer's patch regions of the small intestine while micrometer sized particles enter the body by a process called persorption: the paracellular uptake of microparticles from the digestive tract into the body. These studies have also shown that translocation is largely dependent on particle size: smaller particles are more readily absorbed. Research on the use of microparticles for the oral delivery of drugs, vaccines, and DNA have shown that protein, polysaccharide, and DNA microparticle encapsulation can increase uptake and bioavailability of absorbed molecules. All of these studies have used particles with diameters ranging from 0.1 to 10 μm. Metallic colloidal gold particles can be synthesized in sizes much smaller than micro- and nanoparticles currently being tested for drug delivery.
Digital Knowledge and Diagnostic Information
Authors: Bartels Peter H , Thompson Deborah , Montironi Rodolfo , Hamilton Peter W , Mariuzzi Gian M , Silva Vinicius Duval da
Published: July 2020

Digital representation of diagnostic imagery offers mensuration, numeric data for diagnostic clue expression, objective assessment, and the option to define standards. Quantitative measurement allows the detection and documentation of very small differences and of diagnostic information that is visually not perceived. The automated extraction of such information from microscopic imagery is beginning to yield to knowledge guided image processing and the development of image understanding systems for machine vision. In a machine vision system, knowledge guidance may be provided by an expert system that controls a top to bottom scene segmentation with constant checks on local bottom-up derived segmentation results for compliance with model specifications and final scene reconstruction. Knowledge guidance is based on a knowledge file for the fully autonomous processing of scenes from a given domain. The knowledge file includes all entities representing traditional diagnostic and histologic terms and concepts: epithelium, stroma, lumen, nucleus, secretory cell, basal cell, stroma cell, chromatin, to name a few.
Digital Imaging in Remote Control
Authors: Case Gary N , Vouk Mladen A , Mackenzie John M
Published: July 2020

One of the common problems with current remote control systems is the quality of the digital image that reaches the remote user. The size, resolution, refresh rate, and latency all contribute to the quality of the remote users’ experience. We are working on a series of remote control and display systems that send images over dedicated and production networks to better understand the bandwidth and quality of service issues involved. The amount of bandwidth required is a function of compression, image size and frame rate. Different operations require quite different parameters. Focusing and astigmatism correction require faster frame rates but can be performed with reduced size. Imaging can stand slower frame rates but requires high resolution. The quality of service (QoS) is a measure of latency and how consistently the network delivers the required bandwidth.
Lispix: A Public Domain Scientific Image Analysis Program for the PC and Macintosh*
Authors: Bright D S , Milans K G
Published: July 2020

MacLispix, a public domain image processing system for the Macintosh, has been applied to a variety of image processing problems such as analysis of diffraction spots, uniform display of x-ray maps, determination of fractal dimension of particle outlines, and analysis of data cubes. Due to interest from the PC community, we have ported the software to Windows, renamed it Lispix', and distributed it for both platforms, along with example images, source and documentation.

Lispix reads TIFF files and raw files (no image header), both with pixel types of signed and unsigned 8, 16 and 32 bit integers, 4 and 8 byte IEEE standard floating point numbers, and 3x8 bit RGB color. Lispix has a variety of standard image processing operations, such as thresholding, edge finding (gradient), filtering, scaling, Linear Hough Transform, false coloring, RGB color overlays and particle measurement.
Skeletonization of Fibrin Networks
Authors: Chang S , Kulikowski C A , Dunn S M , Levy S , Weisel J W
Published: July 2020

A complex three dimensional network structure results when blood fibrin polymerizes into branching threads. To understand the rheological behavior of fibrin clots and how this behavior is associated with network morphology, one must obtain quantitative measurements of morphometric parameters of the networks (e.g., fiber diameter, distance between branching points of fibers, and branching complexity) formed under various conditions. Over the past several years, researchers have measured the parameters manually from the 3D reconstruction of networks using stereo images generated with intermediate voltage electron microscopy. Our goal is to help automate this time consuming process as much as possible, and skeletonization is a promising tool. Skeletonization is a process of transforming an object into idealized thin lines. Although various techniques for skeleton computation have been developed, most of them require explicit boundary information of the objects being skeletonized, which is not directly available from raw images.
Structure Determination of Al2CuMg Precipitates in Al-Cu-Mg Alloys by Structure Refinement and Quantitative Image Comparison
Authors: Kilaas R , Radmilovic V
Published: July 2020

Al-Cu-Mg based alloys are of significant interest for aerospace and other applications, due to their low weight, mechanical strength and corrosion resistance. Their mechanical properties are based on a dispersion of S-phase precipitates, which have the composition Al2CuMg. The crystal structure of this inter-metallic phase has been studied using different diffraction techniques for more than five decades. While several models have been proposed for the structure of S-phase[l], only one of the previously proposed models were found to give a reasonable fit to our experimental data. This model, shown in Fig. 1 and given by Perlitz and Westgren (PW) [2] based on X-ray diffraction data, is orthorhombic with unit cell dimensions a = 0:4 nm, b = 0.923 nm, and c = 0.714 nm, space group Cmcm, containing 16 atoms in the ratio Al:Cu:Mg = 2:1:1.

Several HREM images of S-phase precipitates located near the edge of the foil, Fig. 2, recorded along the [100]s and [010]s directions, were digitized from film and used for analysis.
On the Calculation of the Phase Shift of a Superconducting Flux Line Lattice
Authors: Beleggia M , Pozzi G , Tonomura A
Published: July 2020

Recently out-of-focus, low angle electron diffraction and Foucault experiments have been carried out on superconducting specimens in a range of applied magnetic fields where the fluxons form a more or less regular lattice. Let us recall that in order to describe the effect on the electron beam in a transmission experiment of a fluxon in a tilted specimen, the fluxon itself has been approximated by a suitable bundle of straight flux tubes, relying on the important result that the phase shift of the flux tube can be calculated analytically even in the tilted specimen geometry. In this way, it is only necessary to convolute this phase shift with the chosen projected magnetic field distribution (in our case a London model with a phenomenological penetration depth of 50 nm) in order to obtain a fairly realistic model. Therefore, in order to interpret the main features of the experimental results,
Lattice Fringe Visibility after Tilt
Authors: Qin W , Fraundorf P
Published: July 2020

Factors that affect the visibility of lattice fringes include crystal orientation and thickness, as well as instrument response. As a crystal gets smaller, lattice fringes stay visible for larger deviations from the Bragg condition. Hence the persistence of fringes under tilt affects the abundance and range of lattice spacings (and angles) that one sees in an image of randomly-oriented crystals. A subset of the fringes in an image are “still-visible” after large (e.g. 35°) single or double axis tilts. If one is looking for “new-fringes” from the same crystal (e.g. to analyze it's 3D lattice parameters), rules for recognizing redundant fringes might also help out.

Here we examine a semi-empirical model for predicting the visibility of lattice fringes after tilt, by connecting the visibility to intersection of the corresponding crystal reciprocal-lattice spot with the illuminating Ewald sphere.
Spectrum Imaging: Microanalysis for a New Millennium
Authors: Anderson IM
Published: July 2020

Spectrum imaging, where a full spectrum is acquired at each pixel in a two-dimensional array, provides a new paradigm for materials characterization that combines the advantages of traditional paradigms for imaging and analysis in electron optical characterization. Traditionally, electron optical imaging (e.g., secondary electron imaging of electron-opaque or bright-field imaging of electron-transparent specimens) emphasizes contrast production among distinct features of the microstructure. An excellent survey of the specimen microstructure is achieved - many pixels are acquired - but typically no quantitative analysis of image intensities is performed. In contrast, electron optical analysis techniques traditionally concentrate on quantitative elemental analysis (e.g., electron probe microanalysis), or at least comprehensive qualitative analysis through full spectrum acquisition (e.g., energy-dispersive X-ray or electron energy-loss spectrometry). However, these analyses are typically performed at only a few locations on the specimen, which are pre-selected on the basis of the image contrast generated as described above.
Information Extraction: Statistical Analysis to Get the Most from Spectrum Images
Authors: Kotula P G , Keenan M R
Published: July 2020

As more x-ray energy dispersive spectroscopy (EDS) manufacturers begin to offer spectrum imaging (a complete x-ray spectrum from each pixel in an image), there is a clear need for robust and automated methods for quickly extracting the relevant information from the large spectrum image data sets. A typical spectrum image may consist of 100 x 100 pixels (10000 spectra) each with 1000 channels which (when stored at double precision) is 80 Mbytes. It is clear that a large four-dimensional data set such as this cannot be viewed in its entirety and the time to analyze individual spectra by hand is prohibitive. Conventional analysis of spectrum images by mapping energy windows is useful as a first pass only for finding the elements present and only if at sufficient concentrations. Additional problems with mapping include systematic overlaps of other x-ray peaks, changes in the background shape and displaying the maps so they faithfully portray the actual signal intensity.
Prospects and Limitations of Energy Filtering TEM in Spectrum Imaging Analysis
Authors: Mayer J , Pidun M , Karduck P , Zern A , Hahn K
Published: July 2020

The increasing number of energy filtering transmission electron microscopes (EFTEMs) has given many microscopists the ability to apply the fast and very efficient tool of electron spectroscopic imaging (ESI) for analytical characterisation, rather than to record EELS spectra. In a more general framework, the new ESI methods and the standard PEELS technique both aim at exploring the same three-dimensional data space. This data space is represented by the spatial co-ordinates x, y and the energy loss ΔE. The resulting intensity distribution I(x,y, ΔE) is frequently referred to as a spectrum image and the experimental techniques to acquire the corresponding data are referred to as spectrum imaging. The actual analysis can either be based on recording PEELS spectra for a twodimensional array of probe positions, or on recording series of energy filtered images across inner shell loss edges or in the low loss region.
PC/MAC* Image Processing Freeware for Examining Spectral Images
Authors: Bright D S
Published: July 2020

MacLispix, a public domain image processing system for the Macintosh*, has been applied to a variety of image processing problems, such as using Principal Component Analysis to explore correlated images. The tools provided by MacLispix are now available in Lispix, the updated version that runs on both the PC and the Macintosh.

I will illustrate the utility of Lispix by way of an example ‘data cube', a low voltage energy dispersive x-ray spectrum image provided by Ian Anderson. The ‘cube'is 200x150 pixels, each pixel having a spectrum of 512 two-byte channels The spectra were smoothed and reduced by adding adjacent channels to reduce them to 256 channels each. Since Lispix is image oriented rather than spectrum oriented, the reduced cube is stored, and represented internally as 256 images (one image for each channel in the spectrum), rather than as 200x150 spectra (one spectrum for each pixel in the image).
Atomic Resolution Imaging of Thin Film Interfaces
Authors: Larson D J , Clifton P H , Martens R L , Cerezo A , Kelly T F , Petford-Long A K , Smith G D W , Tabat N
Published: July 2020

In recent years there has been a high degree of interest in multilayer film (MLF) structures because of their applications as magnetoresistive sensors and as memory elements in magnetoresistive random access memory arrays. As each of the layers in a spin-valve-based MLF structure1 is only a few nanometers in thickness, the morphology of the layers is crucial in controlling the magnetic and transport properties of the devices. In general, the microstructural features that can influence the film properties include layer roughness, layer composition, interfacial chemical mixing, grain size, grain boundary morphology, and crystallographic orientation, with the most important microstructural parameter being the nature of the interfaces between adjacent layers. With so many internal interfaces, each of which can have a different morphology and degree of intermixing, it is extremely difficult to determine the nature of each individual interface unless a technique is used that can analyze them independently, and with high spatial resolution.
In-Situ TEM Investigation of the Solid/Liquid Interface in Al-Si Alloys
Authors: Storaska Garrett A , Howe James M
Published: July 2020

The solid/liquid interface is a junction between two condensed phases with completely different atomic arrangements. At the interface between the periodically ordered solid and the amorphous liquid, the atoms adopt a structure that minimizes the excess energy due to the abrupt change between the surrounding phases. Faceted and diffuse interfaces describe two extremes in morphology of a solid/liquid interface. In a faceted interface, the change from solid to liquid occurs over one atomic layer, however periodic order extends into the first few liquid layers adjacent to the crystalline solid, as predicted by numerous models.1 The faceted interface advances by nucleation and growth of ledges on the interface. A diffuse interface has a structure in which the change from solid to liquid occurs over several atomic layers. This interface contains many ledges to which liquid atoms may attach continuously as the interface advances.
Synthesis of CaCO3 Thin Films via a Bioinspired Strategy: Cooperative Template-Inhibition
Authors: Xu Guofeng , Yao Nan , Aksay Ilhan A , Groves John T
Published: July 2020

Exquisite control over the morphology of inorganic materials is well demonstrated in biological mineralization. An elegant example is the mulluscan nacre, in which aragonite (a polymorph of calcium carbonate) forms as thin films of about 0.5|im thick between organic matrices as a result of an interplay between templating and inhibition (Figure 1). Not surprising, biomineralization has inspired many recent research efforts in biomimetic materials synthesis, especially the synthesis of inorganic thin films. The majority of these efforts have exclusively focused on exploring the promoting effect on mineral formation by templates. A major drawback of this approach is the lack of control over the mineral growth in the direction normal to the template, which often leads to the formation of discrete patches instead of a true film. In this report, we describe a strategy which takes advantage of the interplay between templating and inhibiting, as utilized by organisms, to synthesize macroscopic and continuous CaCO3 thin films.
An Amorphous to Crystalline Transition in the Formation of CaCO3 Thin Films
Authors: Xu Guofeng , Yao Nan , Aksay Ilhan A , Groves John T
Published: July 2020

Calcium carbonate is one of the most abundant biominerals. Organisms have developed sophisticated controls over its polymorph, morphology and orientation through protein matrices. However, there are many unknowns as to how the matrices affect the crystallization process, in particular, the initial nucleation. A prevailing view is that crystals form via epitaxy from the templates. Alternatively, a crystalline phase could form through a multistep phase transformation, initiated by the formation of an amorphous phase. Since the amorphous phase is more soluble than the stable crystalline phase, it should be the first solid phase formed during the crystallization and therefore could be prevalent in biomineralization. In fact, amorphous phase minerals have been identified in many organisms and more recent discoveries have suggested that amorphous calcium carbonate is more widespread than commonly supposed in biology, but has been overlooked due to the difficulty of identifying an amorphous phase in the presence of a crystalline phase of the same composition.
Strain Field Distribution in Submicron Devices by TEM/CBED. A European Project
Authors: Armigliato A , Balboni R , Carnevale G P , Colpani P , Frabboni S , Pavia G
Published: July 2020

It is now widely accepted that one of the major issues for the future deep sub-micron integrated circuit (IC) technologies regarding yield, device performance and stability and device and product reliability, is the mechanical stress built up in the layers and substrate. It is therefore important to give a quantitative account of these stresses and this can only be achieved by disposing of reliable, performant (as to spatial resolution) and quantitative techniques for the local stress determination in the substrate, of adequate and dedicated process simulation tools and of sensitive methods to analyse the stress effects on device performance.

The only experimental technique presently available which allows the strain field distribution in sub-micron CMOS devices is the convergent beam electron diffraction technique of the transmission electron microscopy. Its sensitivity is of the order of 10-4 and its spatial resolution is of 1 nm if a TEM/FEG is employed.
Quantitative Analysis of Si1-xGex using Convergent Beam Electron Diffraction for Extinction Distance Measurements.
Authors: Delille D , Pantel R , Vincent G , Van Cappellen E
Published: July 2020

Introduction

SiGe epitaxy on Si has been extensively studied, for semiconductor gap modeling and band structure engineering. Quantitative measurement of the Ge concentration is not a trivial exercise at the microscopic level, where classical tools such as X-Ray diffraction, ellipsometry and SIMS cannot be used. A new quantitative microanalytical technique is proposed based on extinction distance measurements using Convergent Beam Electron Diffraction (CBED) combined with dynamical diffraction simulations. A Ge concentration accuracy of less than 2% is demonstrated on strain relaxed SiGe epitaxial layers.

Experiment

Unstrained SiGe epitaxial layers are analyzed for different Ge concentrations, with two-beam CBED, using the transmitted and the 004 diffracted disc. Energy filtered CBED patterns are acquired at 197 keV with a Philips CM 200 FEG transmission electron microscope, using the Ik x Ik CCD camera of the Gatan GIF energy filter. A liquid nitrogen cryo-holder is used, to sharpen up the CBED patterns and to avoid contamination and degradation of the samples.
Defect Dynamics in Simox Structures as a Function of the Annealing Parameters
Authors: Tan Yan , Johnson Benedict , Seraphin Supapan , Anc Maria J
Published: July 2020

Advanced semiconductor devices on the SIMOX (Separation by IMplanted OXygen) substrate have many advantages including high-speed, large packing density and low power consumption. SIMOX consists of a layer structure generated by oxygen ion implantation into silicon wafers. The implantation process introduces a high density of defects that can be reduced by post-implantation annealing. Decreasing the oxygen dose not only reduces the cost but also decreases the damage to the top Si layers. Low-dose implantation results in thinner buried oxide (BOX) layer, in contrast to traditional high-dose SIMOX. The BOX layer formation mechanism is different for low-dose SIMOX from that of high-dose. For a high-dose SIMOX, the BOX layer is already formed by implantation. However, for a low-dose, a number of oxide precipitates are formed during implantation. The larger precipitates grow at the expense of smaller ones until they coalesce to the BOX layer during annealing. This step is known as Ostwald ripening, which is responsible for the thin BOX formation.
Non Destructive Determination of the Threading Dislocation Density of Smooth Simox Substrates using Atomic Force Microscopy
Authors: Domenicucci A , Murphy R , Sadanna D , Klepeis S
Published: July 2020

Atomic force microscopy (AFM) has been used extensively in recent years to study the topographic nature of surfaces in the nanometer range. Its high resolution and ability to be automated have made it an indispensable tool in semiconductor fabrication. Traditionally, AFM has been used to monitor the surface roughness of substrates fabricated by separation by implanted oxygen (SIMOX) processes. It was during such monitoring that a novel use of AFM was uncovered.

A SIMOX process requires two basic steps - a high dose oxygen ion implantation (1017 to 1018 cm-3) followed by a high temperature anneal (>1200°C). The result of these processes is to form a buried oxide layer which isolates a top single crystal silicon layer from the underlying substrate. Pairs of threading dislocations can form in the top silicon layer during the high temperature anneal as a result of damage caused during the high dose oxygen implant.
Effect Of Capping Layer During Annealing of Low-Dose Lowenergy Simox Materials
Authors: Johnson B , Anderson P , Tan Y , Seraphin S , Anc M
Published: July 2020

Ultra-thin Silicon-On-Insulator (SOI) materials are becoming increasingly attractive for fabrication of ultra-large scale integrated (ULSI) devices due to their performance, speed, and power reduction advantages [1]. In SIMOX (Separation by IMplanted OXygen) materials, extensive damage can be repaired by high-temperature annealing in an argon ambient. A small percentage of oxygen is added to give a sufficient oxygen partial pressure to prevent formation of silicon monoxide lumps and subsequent pits [2]. Capping the sample surface to prevent external thermal oxidation during annealing is important to preserve the thickness of the top silicon layer. This is particularly critical for the ultra-thin SIMOX produced by the low-dose low-energy process. However, the surface capping also affects the formation of the buried oxide (BOX). To study this effect, two sets of samples implanted at the same doses of 1.5, 2.0, 2.5, and 3.0x 1017O+ /cm2 at 65keV were annealed with or without protective cap on the sample surface.
Crystallographic Features and Subband Transitions of Al/InAs Metal-Semiconductor Junctions
Authors: Zhang JP , Tsujino S , Thomas M , Allen SJ
Published: July 2020

To study the nature of metal-semiconductor junction, metal-clad InAs quantum wells with aluminum deposited on 15-nm thick InAs grown on (100) GaAs with AlSb barrier were prepared by an in-situ method (aluminum was grown immediately by molecular beam epitaxy) and by an ex-situ method (aluminum was deposited after exposing InAs surface in ambient condition by selective etching). Cross sectional TEM studies indicated that the Al grains in the clad aluminum layer were randomly arranged in the ex-situ grown junctions, while, in the in-situ samples, the aluminum grains were found to be well oriented to the underlying InAs.

When the interface is viewed along [Oil], three observed crystallographic relationships for in-situ Al growth are

1. [011]AI // [011]InAs and (100)AI // (100)InAs as shown in Fig. 1(a): the aluminum grains of facecentered cubic (fee) structure are perfectly aligned with the fee InAs lattice when they grow;