bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electron Spectroscopic Imaging and Analysis in the TEM: Have the Limits Been Reached
Authors: Ottensmeyer F. P. 
Published: June 2020

Electron energy filtering in the transmission electron microscope has had two major applications: 1) contrast enhancement in the image by elimination of chromatic aberrations, and 2) microanalysis by utilization of the information carried in the electron energy loss spectrum.The first application is unique to the fixed beam electron microscope, in which the image suffers from the interaction of the imaging lens with a broad spectrum of electron energies. Since the modal energy loss in the spectrum of 100 kV electrons traversing a carbonaceous light-atom material is about 25 eV per mean-free-path length in the specimen, a lens even with a chromatic aberration constant as good as 1 mm will blur the corresponding image to about 25 Å. In the STEM in which no imaging lenses are used after the electron beam has interacted with the specimen, chromatic aberrations do not occur; at most an effect due to the non-localization of the electron-specimen interaction may be detected as a blurring due to low-loss electrons. Even in the TEM, the effect of energy filtering to use only elastic electrons is small for bright field images of thin specimens stained with heavy atoms, since contrast and visibility is achieved primarily from the predominant elastic scatter from the heavy atoms. However, for dark field microscopy of unstained specimens the effect of filtering is dramatic, since for carbon atoms inelastic scattering dominates elastic scattering by a ratio of 3 to I.
Applications of Confocal Microscopy and Scanning Electron Microscopy to the Localization of Immunoreagents Used in Medical Diagnostic Systems
Authors: Neilly J.P. , Gagne G.D. , Bryant J. , Daanen B. , Schuette K. 
Published: June 2020

Medical diagnostic assays often are based on the immobilization of immunolabeling reagents on solid substrates such as polystyrene beads, microparticles, or membranes. The distribution of immunoreagents on or within these substrates has a significant effect on product performance. Confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM) can be used to localize immunological reagents on beads and other surfaces. In this paper we describe examples in which CLSM and SEM were used to assist in the design and troubleshooting of three diagnostic systems.A protective overcoat is used on HIV antibody-coated 0.25“ polystyrene beads in an HIV screening assay. To visualize topographical detail of the antibody distribution on beads with and without the overcoat, beads were labeled with a fluorescent secondary antibody and examined by CLSM. On overcoated beads, the distribution of HIV antibody was relatively uniform; but on non-overcoated beads, HIV antibody distribution was patchy and located mostly in low areas of the bead surface (Fig. 1), evidence that the overcoat provided protection for the HIV antibody. In the same assay system, performance was enhanced by using beads coated with a mixture of HIV antibodies from two IgG subclasses. The relative distribution of the two primary antibodies on the bead surface was demonstrated using isotype-specific secondary antibodies and CLSM.
Monolayer Morphology and Collapse Induced by Lung Surfactant Protein: Observation Via Fluorescence and Atomic Force Microscopy
Authors: Lipp Michael M. 
Published: June 2020

Understanding the role of lung surfactant specific proteins in lipid monolayers is essential for improved treatments for Respiratory Distress Syndrome, which is a leading cause of death in premature infants. Fluorescence (FM) and Atomic Force (AFM) microscopies reveal that the amino-terminal peptide of lung surfactant protein SP-B alters the behavior of palmitic acid (PA) monolayers, enhancing their in vivo performance. The combination of these techniques provides an excellent correlation between the protein-lipid interactions on the molecular level with the macroscopic properties of the monolayer.SP-B protein incorporates into monolayers of PA, an important component of natural and synthetic lung surfactants monolayers. The effect of the protein on the monolayer is evidenced in the isotherm data shown in Fig 1, in which the area per PA molecule, compressibility, and surface pressure at collapse all increase as a function of increasing protein concentration. The protein accomplishes this by inhibiting the formation of ordered phases of PA. This is seen via FM as a transition from a homogeneous, dark ordered phase without protein (Fig 2a) to a network of a disordered, bright phase (the fluorescent lipid probes used in this study prefer to partition into disordered phases, making them appear as bright regions in FM images) that separates ordered phase domains at coexistence (Fig. 2b). The network is stabilized by the low line tension between the bright phase and other lipid phases as confirmed by the formation of extended linear domains of bright phase in a dark background, or “stripe” phases (Fig. 3a) under certain subphase conditions. Similar stripe phases also occur in single component fluorescein-labeled SP-B monolayers (Fig 3b), implying that the protein is responsible for the reduction in line tension. The formation of the fluid phase network is responsible for the increased collapse resistance of these mixed monolayers. The mechanism of collapse shifts from a heterogeneous process of nucleation and growth of large rigid crystalline collapse phases (Fig. 4a) to a more homogeneous process with nucleation and growth of smaller domains distributed uniformly across the film (Fig. 4b). This is due to the protein-induced network breaking up and isolating the domains of ordered phase, effectively lowering the probability of finding a heterogeneous nucleation site within each domain (analagous to the classic experiments of Turnbull on supercooled microemulsions of metallic liquids). The partitioning of the protein into the bright phase network was confirmed through the use of a dual-probe system. Fluorescein-labeled SP-B was added to a PA monolayer incorporating a fluorescent lipid analogue that emits at a higher wavelength. Upon imaging the same region of a monolayer at the different wavelengths (Fig. 5a and 5b), the protein is seen to be located in the bright phase network regions as expected.
Inhomogeneous Reaction between Epitaxial Al and Si(111) Revealed by Scanning Internal Photoemission Microscopy (IPEM)
Authors: Miyazaki S. , Okumura T. , Miura Y. , Hirose K. 
Published: June 2020

Aluminum is one of the most important materials for the Si LSI metallization. An epitaxial growth of Al films on Si can be achieved since the lattice constant ratio between Al and Si is approximately given by 3 to 4. It is expected that epitaxial Al films are highly stable against thermal annealing. However, epitaxial-Al/Si contacts have sometimes shown a significant change in Schottky barrier height (SBH) and interface structure upon annealing. The objective of this paper is to clarify the relation between the SBH inhomogeneity and the thermally induced reaction between Al and Si through grain boundaries. The microscopic SBH distribution was measured by using scanning internal- photoemission microscopy (IPEM).Epitaxial Al layers were deposited on n-Si(l11) by electron beam evaporation at substrate temperatures of 220°C and 250°C. In the as-deposited state, the Al film fabricated at 220°C consisted mainly of “type-A”- and partially of “type-”"-orientated interfaces (referred to as a mixed phase: MP-AS), while that deposited at 250°C consisted only of “type-B” (referred to as a single phase: SP-AS). The samples were annealed for 1 hour at temperatures between 450-550°C and then quenched.
Intranet Web System, a Simple Solution to Companywide Information-on-demand
Authors: Zhang Xiao 
Published: June 2020

Intranet, a private corporate network that mirrors the internet Web structure, is the new internal communication technology being embraced by more than 50% of large US companies. Within the intranet, computers using Web-server software store and manage documents built on the Web’s hypertext markup language (HTML) format. This emerging technology allows disparate computer systems within companies to “speak” to one another using the Internet’s TCP/IP protocol. A “fire wall” allows internal users Internet access, but denies external intruders intranet access. As industrial microscopists, how can we take advantage of this new technology? This paper is a preliminary summary of our recent progress in building an intranet Web system among GE microscopy labs. Applications and future development are also discussed.The intranet Web system is an inexpensive yet powerful alternative to other forms of internal communication. It can greatly improve communications, unlock hidden information, and transform an organization. The intranet microscopy Web system was built on the existing GE corporate-wide Ethernet link running Internet’s TCP/IP protocol (Fig. 1). Netscape Navigator was selected as the Web browser. Web’s HTML documentation was generated by using Microsoft® Internet Assistant software. Each microscopy lab has its own home page. The microscopy Web system is also an integrated part of GE Plastics analytical technology Web system.
The CM200 Feg-Twin Optimized for Cryo-Electron Microscopy
Authors: Lücken Uwe , Otten Max T. 
Published: June 2020

The requirements for cryo-electron microscopy are: good vacuum, high resolution under low-dose conditions at low magnification, low drift with cooled cryo-transfer holders and, in some cases, fast spotscan imaging. For our cryo microscopes we have introduced special factory tests in which these specifications will be met.In order to obtain high spatial frequencies at low magnification an appropriate specimen with a statistical distribution of small spacings and a fine-grained recording film is needed. We used amorphous tungsten on carbon as specimen and overexposed and underdeveloped Agfa Scienta film (Fig. 1). The laser diffractogram in Fig. 2 presents Thon rings out to 0.19 nm in a one-second exposure flood-beam image. The result of a similar experiment done with a cooled cryo-transfer holder is shown in Fig. 3. Flood-beam images of gold islands and carbon black on a thin carbon film were taken at 66 OOOx at liquid-nitrogen temperature with one second exposure under low-dose conditions. The laser diffractogram clearly shows Thon rings out to 0. 2 nm.
Development of High-Definition Image Processing System for a FE-SEM
Authors: Yamada M. , Yoshihara T. , Arima H. , Nimura Y. , Kobayashi T. , Nielsen C. 
Published: June 2020

This paper presents the development of a new, fully digital image processing system for a field emission SEM (FE-SEM) which can eliminate fluctuations in the emission current. The system can display, in real time, images with 1280 × 1024 pixels on a viewing CRT, allowing direct observation of high definition SEM images on the FE-SEM.In the past, even though image was acquired and recorded (photographed) with the resolution higher than 1,000 x 1,000 pixels, it was generally observed on the viewing CRT at the resolution of only about 500 x 500 pixels for real-time observation. This created a difference in image quality between the two CRT's. Using a CRT of the same pixel resolution for observation as on the recording CRT, the difference in image quality can be minimised, provided that the characteristics (speed and resolution) of the image processing and scan generator system are improved and optimised for digital processing.
ALCHEMI of B2-Ordered Fe50Al45Me5 alloys
Authors: Anderson Ian M. 
Published: June 2020

B2-ordered iron aluminide intermetallic alloys exhibit a combination of attractive properties such as low density and good corrosion resistance. However, the practical applications of these alloys are limited by their poor fracture toughness and low room temperature ductility. One current strategy for overcoming these undesirable properties is to attempt to modify the basic chemistry of the materials with alloying additions. These changes in the chemistry of the material cannot be fully understood without a knowledge of the site-distribution of the alloying elements. In this paper, the site-distributions of a series of 3d-transition metal alloying additions in B2-ordered iron aluminides are studied with ALCHEMI.A series of seven alloys of stoichiometry Fe50AL45Me5, with Me = {Ti, V, Cr, Mn, Co, Ni, Cu}, were prepared with identical heating cycles. Microalloying additions of 0.2% B and 0.1% Zr were also incorporated to strengthen the grain boundaries, but these alloying additions have little influence on the matrix chemistry and are incidental to this study.
EXELFS analysis of natural diamond and diamond films on si substrates
Authors: Moller A. Duarte , Araiza L. Cota , Borja M. Avalos 
Published: June 2020

In this work, we report the EXELFS results obtained from a polycrystalline diamond film grown on smooth silicon substrates using the Hot Filament Chemical Vapor Deposition (HF-CVD) technique in a two-step deposition process published elsewhere. In order to evaluate the quality of the thin film obtained, these results were compared with results obtained from natural diamond. The diamond sample was prepared in cross-section by ion milling where the nominal size of diamond.particles was about 1 μn. The EXELFS experiments were performed in a JEOL-2010 Transmission Electron Microscope with a GATAN-666 PEELS attachment. A primary energy of 200 KeV was used with an average acquisition time of 5 minutes. The extended fine structure (EFS) energy range was 300 eV. In order to obtain the local structure, the standard procedure developed for EXAFS was applied here. The natural diamond particles with a nominal size of 1 μn were taken from commercial powder.
Use of digital microscopy in process control during the manufacture of rubber-modified thermoplastics
Authors: Dineen M. T. 
Published: June 2020

The production of rubber modified thermoplastics can exceed rates of 30,000 pounds per hour. If a production plant needs to equilibrate or has an upset, that means operating costs and lost revenue. Results of transmission electron microscopy (TEM) can be used for process adjustments to minimize product loss. Conventional TEM, however, is not a rapid turnaround technique. The TEM process was examined, and it was determined that 50% of the time it took to complete a polymer sample was related to film processing, even when using automated equipment. By replacing the conventional film portion of the process with a commercially available system to digitally acquire the TEM image, a production plant can have the same TEM image in the control room within 1.5 hours of sampling.A Hitachi H-600 TEM Operated at 100 kV with a tungsten filament was retrofitted with a SEMICAPS™ image collection and processing workstation and a KODAK MEGAPLUS™ charged coupled device (CCD) camera (Fig. 1). Media Cybernetics Image-Pro Plus software was included, and connections to a Phaser II SDX printer and the network were made. Network printers and other PC and Mac software (e.g. NIH Image) were available. By using digital acquisition and processing, the time it takes to produce a hard copy of a digital image is greatly reduced compared to the time it takes to process film.
Critical issues in ceramic microstructures
Authors: Clarke D. R. 
Published: June 2020

As the number and variety of ceramic materials have grown so rapidly in the last few decades, ranging from silicon nitride structural ceramics to the perovskite superconductors to the ferroelectric oxides to semiconducting sensors, the number of scientific and technical issues has also grown rapidly. Many of the basic questions relate to the role the microstructures play in determining the observed physical behavior but increasingly it is not the geometric properties of the microstructure that are of central concern but rather compositional variations and associated electrical characteristics. These require the continued development of microscopy techniques to complement the tremendous advances in microstructural understanding that have already been made possible by microscopy in the past.Since the role of microscopy is such a broad one, only a few of the most generic problems in microstructure characterization will be described in this talk. The topics selected include the characterization of intergranular films in liquid-phase sintered ceramics, the charge distribution at interfaces and the associated space charge, the epitaxial growth of oxides on oxide substrates, and the use of fluorescence imaging to identify phases and non-destructively measure local strains.
Characterization of crystalline titanium dioxide synthesized at room temperature
Authors: Gopal Mani 
Published: June 2020

A process has been developed to synthesize crystalline titanium dioxide powders from aqueous solutions at low temperatures (T<100°C) and atmospheric pressure. Processing at slow reaction rates causes the formation of the thermodynamically favored rutile phase. Faster reaction rates promote the formation of anatase, the statistically favored phase. Processing at intermediate rates causes a mixture to be formed (Fig. 1). This paper reports the TEM and SEM characterization of rutile, precipitated at 40°C.Specimens for TEM were collected on holey carbon grids suspended vertically in the stirred solution. After removal, the grids were washed in isopropyl alcohol and dried under a heat lamp. For SEM analysis, a drop of the solution was placed on the specimen holder and dried. The top surface was then washed with isopropyl alcohol to remove any contamination and observed.The bright field image (Fig. 2b) of the rutile precipitates shows them to have a nominal size of 50-100 ran. The sharpness of the (002) ring in the electron diffraction pattern (Fig. 2a) indicates the needles are elongated in the [002] direction. The corresponding dark-field image (Fig. 2c) shows that individual needles are comprised up of smaller particulates (HR-TEM shows them to be ∼3 nm in size). It is important to note that in each needle, all the particulates diffract together or they all do not, indicating a common orientational relationship.
Electron-Beam-induced transformations in zirconia-alumina nanolaminates: An In situ high-resolution Electron–Microscopy study
Authors: Schofield M.A. , Gajdardziska-Josifovska M. , Whig R. , Aita C.R. 
Published: June 2020

Composite systems containing zirconia have been used extensively as transformation-toughening materials based on a stress induced martensitic transformation of the metastable tetragonal phase of zirconia to the monoclinic phase. Recently it has been shown that tetragonal zirconia can be stabilized in zirconia-alumina nanolaminates grown by reactive sputter deposition, when the zirconia layer is less than 6 nm thick. Cross-section high resolution transmission electron microscopy (HRTEM) of these nanolaminates revealed localized tetragonal-to-monoclinic transformation caused by sample preparation. In this study, quantitative HRTEM is used to analyze the zirconia nanocrystallite transformation in situ, by controlled exposure of the sample to the electron beam of the microscope.The irradiation conditions used in this study to induce the zirconia transformation are summarized in Table 1. The mildest irradiation condition corresponds to normal imaging illumination used in this study to obtain high resolution images. Under these normal illumination conditions, the first condenser lens (CI) is used to form a 0.1 μm sized probe which is over focused on the sample by the second condenser lens (C2).
Adrenal gland ultrastructural pathology in plasmodium berghei parasitized mice
Authors: Pulido-Méndez M. , Finol H.J. , Rodríguez-Acosta A. , Márquez A. , Aguilar I. , Girón M.E. , González N. , García-Tamayo J. 
Published: June 2020

The use of animal models is widely accepted in malaria research. Plasmodium berghei has been extensively studied because it produces a mortal malaria in rodents. Electron microscopic studies on brain and liver pathology have been performed in this infection. In a previous ultrastructural work we reported the capillary alterations observed in adrenal cortex in P. berghei infected mice. In this work we describe the cell and capillary changes we found in adrenal cortex and medulla in this infection.Male mice weighing 18-22 g were inoculated intraperitoneally with P. berghei infected erythrocytes. At the ninth day animals were sacrificed when parasitemia ranged between 80-90%. Adrenal gland samples were processed by routine techniques and observed in a Hitachi H-500 transmission electron microscope.
Oxidative injury and endothelial cell dysfunction in diabetic retinopathy: A combined cytochemical and immunocytochemical study
Authors: Ellis E. Ann , Grant Maria B. , Murray Frederick T. , Wachowski Martha B. 
Published: June 2020

Endothelial cell dysfunction has been implicated in a number of microvascular complications of diabetes. Microvascular changes in diabetic retinopathy present initially as leaky vessels in the neural retina which lead to deterioration of vision. Oxidative injury as a result of free radical production has been suggested as a mechanism of endothelial cell dysfunction caused by hyperglycemia.The NADPH oxidase complex catalyzes the formation of superoxide (O2·−); hydrogen peroxide (H2O2) is formed by dismutaion of O2·−. Cytochemical localization of the free radical derived oxidant, H2O2, was done by the cerium NADPH/NADH oxidase method in eyes of obese, noninsulin dependent diabetic BBZ/Wor rats with diabetes of five and ten months duration. Age matched, nondiabetic controls were eyes from BB/WorDRrats. Endothelial cell dysfunction, indicated by leaky vessels, was documented by colloidal gold immunocytochemical localization of extravasated endogenous serum albumin on sections of retina in which H2O2had been localized.
Localization of endothelial nitric oxide synthase in the normal and failing human atrial myocardium
Authors: Wei Chi-Ming , Bracamonte Margarita , Jiang Shi-Wen , Daly Richard C. , McGregor Christopher G.A. , Zhang Shaobo , Young Charles Y. F. 
Published: June 2020

Nitric oxide (NO) is a potent endothelium-derived relaxing factor which also may modulate cardiomyocyte inotropism and growth via increasing cGMP. While endothelial nitric oxide synthase (eNOS) isoforms have been detected in non-human mammalian tissues, expression and localization of eNOS in the normal and failing human myocardium are poorly defined. Therefore, the present study was designed to investigate eNOS in human cardiac tissues in the presence and absence of congestive heart failure (CHF).Normal and failing atrial tissue were obtained from six cardiac donors and six end-stage heart failure patients undergoing primary cardiac transplantation. ENOS protein expression and localization was investigated utilizing Western blot analysis and immunohistochemical staining with the polyclonal rabbit antibody to eNOS (Transduction Laboratories, Lexington, Kentucky).
Interaction of internalized, viable listeria monocytogenes with MHC class II molecules and low pH compartments
Authors: Iadarola Linda , Webster Paul 
Published: June 2020

Listeria monocytogenes, an aerobic, non-sporulating, gram-positive bacillus, is a contaminant of the food we eat and is capable of surviving in the cytoplasm of infected cells. Ingestion of contaminated foods by susceptible individuals (newborn, elderly and immuno-compromised) can result in severe systemic disease resulting from opportunistic infections. There is a high case fatality rate in immunocompromised individuals.During the course of infection, L. monocytogenes invades cells by adhering to the cell membrane from where the bacteria are internalized into membrane bound phagosomes. Disruption of the phagosome membrane allows the bacteria to gain access to the cell cytoplasm where they grow and multiply. In the cytoplasm, actin polymerization on the bacteria surface cause them to move in the cell and form long cytoplasmic protrusions at the cell surface. The protrusions, with a bacterium at the tip, are taken up by adjacent, uninfected cells which then become infected.