bluuebunny/crossref_metadata_2025_split huggingface dataset:
Spark Ignition Motor Vehicle Exhaust Particulate Matter Characterization
Authors: Blom Douglas A , Nolan Ted A 
Published: July 2020

Abstract
The Northern Front Range Air Quality Study concluded that for the Denver metropolitan area during 1996 and 1997, 55% of particles with an aerodynamic diameter 50% cutpoint of 2.5 μm (PM2.5) were attributable to motor vehicle exhaust particulates. The health effects of PM2.5 are currently unknown, but are under investigation. It is of vital interest to understand the chemistry, morphology, size distribution and microstructure of motor vehicle exhaust. The techniques of transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDS) appear to be well suited for the analysis of the microstructure, morphology and microchemical composition of particulate matter. Previous electron microscopy observations of particulate matter from a variety of sources have found that the chemical composition and crystal structure are characteristics of the source of the particles.
As part of an ongoing research project into the health effects of motor vehicle particulate matter, Southwest Research Institute (SWRI) is performing chassis dynamometer tests of a variety of vehicles and collecting samples from the exhaust stream for analysis.
Signaling by Calcium and the RHOA GTPASE: Relating Structure to Function
Authors: Somlyo AP , Somlyo AV 
Published: July 2020

Abstract
We will review the results of structural approaches used in our laboratory for evaluating the roles of calcium (Ca2+) and the small GTPase, RhoA, in normal and pathological cell signaling.
An early method, using strontium (Sr) as an electron opaque marker of mitochondrial Ca, was first used to localize this “Ca2+ surrogate” in the sarcoplasmic reticulum (SR) of smooth muscle. Subsequent development of electron probe X-ray microanalysis (EPMA) and electron energy-loss spectroscopy (EELS) allowed the direct and quantitative detection of intracellular Ca in smooth, skeletal and cardiac muscles. The major conclusion of these studies was that, in all muscles, the SR is the major intracellular sink/source of activator Ca2+. The high ratio of total/free cytoplasmic Ca2+ indicated the presence of significant cytoplasmic Ca buffers not only in striated, but also in smooth muscles, and EPMA of frog skeletal muscle showed that the time course of changes in cytoplasmic Ca during relaxation was consistent with the off-rate of Ca2+ from the Ca2+-buffer, parvalbumin.
Analysis of the Atomic Scale Oxygen Vacancy Ordering by EELS and Z-Contrast Imaging
Authors: Ito Y , Stemmer S , Klie RF , Browning ND , Mazanec TJ 
Published: July 2020

Abstract
Perovskite-type oxides with high electronic and ionic conductivity are very promising materials for use as dense ceramic membranes for oxygen separation. For the successful implementation of practical ceramic membranes, a full understanding of the parameters controlling the degree of non-stoichiometry, i.e. the defect chemistry is essential. A combination of Z-contrast imaging and electron energy loss spectroscopy (EELS) in the scanning transmission electron microscope (STEM) can be used to directly image crystal and defect structures and the effect of the structures on the local electronic properties (i.e. oxygen coordination and cation valence). Here the defect chemistry in SrCoO3-δ before and after a reduction treatment at high temperatures is investigated in the JEOL 201 OF STEM. This material is known to exist in a wide a variety of phases with different crystal structures, compositions and valence states of cobalt, and can be highly oxygen deficient.
Development and Application of a New 300kv Omega-Filter Electron Microscope
Authors: Bando Y , Mitome M , Kitami Y , Kurashima K , Kaneyama T , Okura Y , Naruse M 
Published: July 2020

Abstract
It has been already pointed out that the medium voltage microscopes of 300kV to 400kV have some advantages in the analytical capabilities of EDS and EELS as compared to those of 200kV). The P/B ratios and the spatial resolution for the analysis will be improved with the increase of the accelerating voltages as well as lattice resolution. In order to improve the spatial resolution of inelastic filtered images, we have recently developed a new 300 kV omega-filter electron microscope with a field emission gun. In the paper, some characteristic features of the new microscope and its application results are described.
The new microscope have a 300kV field emission gun, an omega-filter, EDS, digital STEM, a slow-scan CCD, an imaging plate and TV camera. Some characteristic features of the new microscope are summarized in Table 1. Based on a calculation of probe diameter as a function of probe current at 300kV in a Shottkey type gun with a brightness of 7xl08A/cm2sr and Cs of 0.6mm, a minimum probe size (FWHM) is estimated to be about 0.2nm (Fig. 1).
Structural Analysis of gp6 and gp6/gpl5/gpl6 Complex by Cryo-Electron Microscopy At 10 Å Resolution
Authors: Orlova EV , Lurz R , Droege A , Gowen B , Tavares P , van Heel M 
Published: July 2020

Abstract
The mechanism of encapsidation of DNA into a bacteriophage head is a most intriguing problem. The portal protein is essential for the assembly of tailed double-stranded DNA (dsDNA) bacteriophages. These turbine-like homo-oligomers consist of 12 or 13 subunits surrounding a central channel. Portal oligomers are located at the vertex of the icosahedral head that binds to the phage tail. It was shown that gp6 portal protein from bacteriophage SPP1 has 13 subunits, prior to their incorporation into the viral procapsid structure. After packaging of the viral DNA inside the phage capsid, additional proteins have been found attached to the portal oligomer: gpl5 and gp 16. A complex of gp6/gpl5/gpl7 forms the connector structure that provides the interface for attachment of the phage tail. We here present the three-dimensional (3D) reconstructions of the gp6 wild-type protein alone and of the gp6/gpl5/gpl6 complex - both at 10Å resolution - based on electron cryo-microscopy using the angular reconstitution single particle methodology.
Single Particle Reconstruction of the Vault from TEP1 Knockout Mice and Refinement of the Computationally Selected Vault Barrel
Authors: Stewart PL , Kong LB , Siva AC , Kickhoefer VA , Harrington L , Rome LH 
Published: July 2020

Abstract
The vault complex is a ubiquitous and predominantly cytoplasmic 13 MDa ribonucleoprotein assembly, composed of three proteins (TEP1, 240 kDa; VPARP, 193 kDa; and MVP, 100 kDa) and an untranslated RNA (vRNA) Although the basic cellular function of the vault is still unclear, recently it has been shown that induction of the major vault protein (MVP) has a direct negative influence on the nuclear uptake of the anti-cancer drug, doxorubicin. We have been applying cryo-EM single particle reconstruction methods to study the structure and molecular architecture of this cellular component. A published reconstruction of the intact rat vault at 31 Å resolution revealed that the complex is hollow and is structurally well suited to serve in macromolecular transport or sequestration. Higher resolution, 23 Å, was achieved for a reconstruction of the RNase-treated rat vault and difference imaging with the intact rat vault localized the vRNA to the ends of the vault caps.
Single Particle Reconstruction of Human Fatty Acid Synthase
Authors: Brink J , Ludtke SJ , Yang C-Y , Gu Z-W , Wakil S , Chiu W 
Published: July 2020

Abstract
Fatty acid synthase (FAS) is the enzyme responsible for de novo synthesis of fatty acids from acetyl-CoA, malonyl-CoA and NADPH. FAS (550 kDa) is a homodimer of two multifunctional polypeptides, each with seven distinct catalytic activities and a site for the prosthetic group, 4’- phosphopantetheine, acyl carrier protein (ACP). These domains are organized from the N- to the C-terminus as follows: keto acylsynthase, acetyl/malonyl transacetylase, dehydratase, the interdomain, enoyl reductase, ketoreductase, ACP and thioesterase. The two polypeptides are held together through the interdomain and oriented in an anti-parallel manner, each contributing complementary half sites and giving rise to two independently active centers for palmitate synthesis. Interest in FAS arises from its involvement in human disorders, such as obesity, hyperlipidemia and carcinogenesis.
Human FAS purified from a breast cancer cell line, ZR75-1, was vitrified at 50-70 μg/ml on holey grids in the presence of NADPH and acetyl-CoA and kept at -166°C in a Gatan 626 cryo-holder.
Comparison of Particle Size Analyses from FEG-SEM and TEM Images
Authors: Lanteri S , Gendt D , Barges P , Petitgand G 
Published: July 2020

Abstract
Much effort has recently been employed in modeling steel behavior as a function of chemical composition and thermo-mechanical processing. In order for the models to be predictive, experimental data are needed to first calibrate and then validate the calculated results. Since many steel properties are conditioned in part by the state of precipitation, this study was undertaken to provide experimental measurements of precipitates in terms of their size distributions. Due to the size range (2-100 nm) of particles which exert the greatest influence on the mechanical properties, electron microscopy is practically the only technique available for obtaining images of the precipitates.
Two types of micrographs were used for image analysis in order to determine the size distribution of NbC particles present in a ternary alloy (Fe-Nb-C) heat treated at 800°C for 1000 mn. Polished surfaces lightly etched with a solution of 2% HNO3 and 98% ethanol were prepared for observations in a LEO 1550 scanning electron microscope equipped with a field emission gun.
Evaluation of Cardiomyocyte Viability after Cardiac Tissue Incubated in Special Culture System
Authors: Wei C , Papadimitriou J 
Published: July 2020

Abstract
Cardiac myocytes maintained in cell culture develop hypertrophy both in response to mechanical loading as well as to receptor-mediated signaling mechanisms. However, it has been shown that the hypertrophic response to these stimuli may be modulated through effects of intercellular contact achieved by maintaining cells at different plating densities. We recently developed the new special tissue culture system to culture minced cardiac tissue and to evaluate the apoptotic effect of different agent in cardiomyocytes. After 24 hours culture period, different culture conditions and factors may damage the cardiomyocyte. Therefore, we performed different methods to evaluate the viability of cardiomyocyte in cardiac tissue with 24 hours culture period in our special culture system.
Human cardiac atrial tissue was obtained from open-heart surgery (n=6). After cardiac tissue excision, the samples were immediately placed in oxygenated, nominally Ca2+-free Tyrode solution for transport to the laboratory. The time between excision and the beginning of laboratory processing was five to fifteen minutes.
The Action of C-Type Natriuretic Peptide on Apoptosis and P53 Expression in Human Cardiomyocytes
Authors: Seta K , Matsuda Y , Wei C 
Published: July 2020

Abstract
C-type natriuretic peptide (CNP) is endothelial cell origin and has potent vasodilatory and antimitogenic actions. We reported that CNP was markedly increased in human cardiac tissue with severe congestive heart failure. To date, the effects of CNP on cardiomyocyte growth and death remain unclear. Therefore, the present study was designed to investigate the actions of CNP on apoptosis and apoptosis-related gene p53 expression in human cardiomyocytes.
Human cardiac atrial tissue was obtained from open-heart surgery (n=6). The cardiac tissue was minced and incubated in the special tissue culture system in the absence or presence of CNP (10-7 M) for 24 hours. These studies were repeated with HS-142-1 (HS, 10-6 M), a natriuretic peptide biological receptor antagonist. To detect the DNA fragmentation, in situ terminal deoxymucleotidyl transferase dUTP nick end labeling (TUNEL) was performed. The p53 expression was determined by immunohistochemical staining (IHCS). An average of 1000 nuclei was analyzed for TUNEL and p53 staining studies.
Use of the Vital Stain FM4-64 for Visualizing Membrane Dynamics in Living Fungal Cells
Authors: Roberson RW , Fisher KE , Lowry DS 
Published: July 2020

Abstract
Allomyces macrogynus is a zoosporic fungus (Chytridiomycota) that exhibits a true alternation of generations between the diploid and haploid thalli. During the diploid stage in the life cycle, sporothalli are produced which are capable of forming asexual zoosporangia containing a multinucleate protoplast bound by a single plasma membrane and cell wall. Though able to remain in a quiescent, coenocytic state for an extended period of time, under certain environmental conditions the cytoplasm of mature zoosporangia is cleaved and gives rise to numerous uninucleate, uniflagellate zoospores within 40 to 50 min. Previous studies of cleavage membrane development m Allomyces zoosporangia have been conducted using light microscopy and transmission electron microscopy (TEM). Despite these investigations, our understanding of cytokinesis in zoosporangia of Allomyces and other zoosporic organisms remains incomplete. This is due, in part, to the difficulty of detecting cleavage elements using standard light microscope optics (i.e., phase contrast, differential interference contrast) and because ultrastructural analysis often provides limited temporal and spatial detail and may suffer from artifacts of sample preparation.
Automated Analysis of Data Mark Microstructure of Optical Discs
Authors: Chernoff D A , Cook C S , Burkhead D L 
Published: July 2020

Abstract
Introduction. By volume of material produced, optical disc manufacturing is the world's large nanotechnology industry, far surpassing semiconductors and magnetic disks. The development of various optical disc media has introduced a variety of challenges, which necessitate viewing the geometrical structure of the bumps, pits, or grooves on the surface of the discs. The Atomic Force Microscope (AFM) has the resolution and sensitivity needed for device analysis, but in the past has been limited by magnification errors, image distortion, data handling, and calibration. Furthermore, the common measurement procedure for AFM images consists of manual dimensional measurements. This introduces error and limits the number of measurements taken at one time. We have developed an automated process, which overcomes these limitations and provides a comprehensive approach to feature measurement, data analysis, calibration, and reporting.
LVSEM Surface Sampling, Preparation, Peak Overlap, Convergent Analysis and Covering up the FESTEM Aperture Charging Problem
Authors: Boyes E D 
Published: July 2020

Abstract
Surfaces The majority of the SEM secondary electron signal (SE) comes from the first few (&lt;2nm) nanometers of the surface. The quality of the outermost few atomic layers of an exposed and reactive sample can therefore have a profound effect on image contrast. With light elements and low voltages the SE signal is dominated by scattering at the point of incidence of the primary probe, but more generally there is a significant contribution to surface SE generation by primary electrons backscattered from deeper in the sample. With the advent of very low voltage EDS, and the application of more conventional surface science methods, we learn that even without a coating the surface of a sample may be atypical of the bulk (Fig. 1). Contamination of an otherwise clean surface occurs by transport of the sample through the air, leading to oxidation, hydrocarbon accumulation, and occasionally to rather more dramatic pyrophoric effects.
Contact Angle Measurement in the Environmental Scanning Electron Microscope (ESEM)
Authors: Craven JP , Stelmashenko NA , Terentjev EM , Thiel B L 
Published: July 2020

Abstract
The ESEM uses a novel differential pumping system combined with a pressure-limiting aperture to achieve relatively high pressures of up to 10 torr in the specimen chamber. Using this system allows samples to be imaged in the presence of water vapour or other gases. Conveniently the saturated water pressure at 275K lies within this range, allowing the stabilisation of hydrated samples, condensation from water vapour and evaporation to be performed in situ within the microscope chamber.
Wetting of surfaces is of fundamental importance in many different areas of science, from textiles to petroleum engineering. The ESEM now provides an opening for high-resolution studies of these phenomena without the problematic depth-of-field limitations that optical methods present. The contact angle, θ, is defined as the angle between the tangent to the liquid-fluid interface and the tangent to the solid interface. It provides a ready indication to the wetting properties of a system.
Leaf Surface Morphology of Urban Tree Species and Its Contribution to Particle Pollution Removal
Authors: Abdollahi Kamran K , Ning Zhu H 
Published: July 2020

Abstract
According to the findings by the National Resource Defense Council (NRDC), dust, soot, and many particles in polluted air over the nation's 239 major cities cause 64,000 of premature heart and lungrelated deaths each year. In light of the new reports, the Environmental Protection Agency (EPA) has announced the plan to impose tougher restrictions to include fine particulate less than 2.5 microns (PM2.5). The new regulations could cost more than $2.5 billion a year to implement in a city like Chicago alone. Urban trees as a component of urban ecosystem can provide cost effective phyto-mitigation and phyto-remediation strategy for improving urban environment and quality of life. Previous studies have indicated that trees in Chicago removed 234 tons of particulate matter less than 10 microns (PM10) annually. To the extend that trees can control particulate pollution there is potential for improved air quality and substantial cost savings.
Physicochemical Identification and Comparative Biopersistence of Indoor and Outdoor Airborne Particulate Matter
Authors: BéruBé K , Jones T , Richards R 
Published: July 2020

Abstract
People spend the majority of their time indoors, mostly in the domestic environment, where there may be significant air pollution sources. Indoor air pollutants can be derived from the ingress of contaminated air from outdoors (e.g., heavily trafficked roads, presence of industry, allergens) and from specific indoor sources such as combustion appliances, building materials, and consumer products. The activities and behaviour of individuals, for example, cooking, heating, cleaning, smoking, pets, can also influence the production and levels of indoor air pollutants. There is a body of literature concerning indoor concentrations of pollutants such as CO, NO2, formaldehyde, volatile organic compounds, house dust mites, fungi, bacteria and their health effects. However, there have been few, if any studies, conducted in the UK to date to compare and contrast indoor and outdoor particulate matter (PM). Epidemiological studies consistently suggest that increases in outdoor PMIO (particulate matter with an aerodynamic diameter of less than l0μm) concentrations are linked to health effects (morbidity and mortality in persons with cardiopulmonary diseases).
Phase Identification in Mixed Oxide Capacitors Using Electron Backscatter Diffraction and X-Ray Diffraction
Authors: Adams P M , Hoskinson C T , Witt R 
Published: July 2020

Abstract
A group of mixed oxide ceramic capacitors used in several electronic systems recently failed as a result of voltage breakdown in the specified test ranges. These capacitors consist predominantly of mixed oxides of magnesium, titanium, silicon and aluminum (with minor amounts of strontium and calcium) and contain palladium mesh electrodes. Preliminary results suggest that phase transformations have occurred in some lots of capacitors that have been over-fired as a result of a manufacturing change. Several years’ production of capacitors has potentially been affected. The formation of a phase with inferior dielectric properties, and which can exhibit semiconducting properties (P/N junction), probably resulted in the failure of the capacitors. This new phase is typically rich in strontium and is only present at levels of several volume percent. The low concentration of this phase has made its identification difficult. If this new phase could be identified it might be possible to determine/establish if its dielectric properties are consistent with the proposed failure mechanism.
The Role of Microscopy in the Study of Chemical Polymorphism
Authors: Carlton RA 
Published: July 2020

Abstract
Chemical polymorphism refers to the ability of compounds to exist in different solid state forms. In general, these differ solely in their arrangement in space (i.e., their crystal form). Polymorphs typically have different solid state properties such as melting point, solubility, density, etc. They also commonly exhibit distinctive optical properties such as refractive index, extinction position, optic sign and optic angle. The choice of polymorph can be an important consideration in the drug development process if the solid state properties have wide differences. Further, it is generally desirable to develop the polymorph which is stable at room temperature and pressure, since metastable forms convert spontaneously to the stable ones, albeit often at a very slow rate. Optical, thermal and scanning electron microscopy each play important roles in the study of chemical polymorphism.
Optical microscopy, and more specifically polarized light microscopy, contributes both to the discovery of new polymorphs and to the elucidation of the relationship among polymorphs.
Energy Dispersive X-Ray (EDX) and Electron Energy-Loss (EELS) Spectroscopic Mapping of Microelectronic Devices
Authors: Bruley J , Flaitz P 
Published: July 2020

Abstract
Many crucial measurements in the semiconductor industry involve determining the root cause of an electrical failure, often requiring the capability of extracting microstructural and chemical information with nanometer resolution [1]. The microanalysis is achieved by stepping the focused probe over the region of interest in STEM mode and recording an EDX and EELS spectrum at each pixel. Even for relatively modest image sizes, the resultant spectrum-image may consist of more than 10,000 spectra. With such large data sets, the prospect of manually inspecting and quantifying each spectrum in real-time is impossible and even automatic background modeling followed by peak area integration over selected spectral regions-of-interest can be excessively time consuming. Other methods to extract useful physical information include “fingerprinting” characteristic ELNES shapes to known compounds or bonding environments, multiple least squares regression to a relatively small set of suspected components or peak-fitting to model systematic changes in electronic density of states.