bluuebunny/crossref_metadata_2025_split huggingface dataset:
Where Art Thou, Calcium?
Authors: Bailey GW , Dimlich RVW , Alexander KB , McCarthy JJ , Pretlow TP , Somlyo AP 
Published: July 2020

Abstract
Ever since the recognition of calcium as a major intracellular messenger of signal transduction, its subcellular localization and intracellular movements have been intensively sought through electron and light optical methods. Electron probe microanalysis (EPMA), X-ray mapping, electron energy-loss spectroscopy (EELS) and energy-filtered imaging still provide the highest spatial resolution for measuring total calcium, whereas with light optical methods (fluorescent, luminescent and absorbance dyes) free [Ca2+]i can be measured with high sensitivity and time resolution. This presentation will summarize the relationship, whether collision or convergence, between the results of electron and light optical methods, with particular reference to mitochondrial Ca, and consider the potential for further improvements in detection sensitivity and spatial resolution.
Sarcoplasmic and endoplasmic reticulum: Early attempts to quantitate Ca in cellular organelles with EPMA were directed at the sarcoplasmic reticulum (SR) of skeletal muscle, where EPMA could also address questions not amenable to studies of isolated SR.
Esi Analysis Shows Alveolar Epithelial-Like Cells Ingest 50 Nm Titanium Dioxide Particles
Authors: Stearns RC , Godleski JJ 
Published: July 2020

Abstract
Although alveolar macrophages are the primary defensive cells of the lung against invading bacteria and foreign particles, recent studies suggest that particle uptake and translocation is a role common to alveolar epithelium (reviewed by Churg). The purpose of this investigation is to define the phagocytic capabilities of human A549 cell line using 50 nm inert Titanium Dioxide, (TiO2), particles.
A549 cells at 0.5×l06cells/ml, in F12 Kaighn’s modification medium (F12K) with 10% heat-inactivated fetal bovine serum, l00U/ml penicillin and lOOng/ml streptomycin were cultured on alcar discs in 24-well plates, incubated at 37°C, 5% CO2 in a humidified incubator for 4 days. The cells were then exposed to TiO2 particles (final concentration 4Oμg/ml) in serum-free F12K media for 24 h. After 24h, the cells were fixed in 2.5% glutaraldehyde in 0.1 M potassium phosphate buffer overnight. The cells were post-fixed with 1% OSO4, dehydrated in series of ethanol and propylene oxide, infiltrated and embedded with araldite 502.
What Are Present Limits of Quantitative High Resolution Tem?
Authors: Kisielowski Christian 
Published: July 2020

Abstract
In recent years quantitative high resolution electron microscopy (HREM) became a reliable tool to investigate physical processes at an atomic scale. Certainly, there is no unique approach to quantify the information content from lattice images. However, specific methods like Chemical Imaging^ and QUANTITEM were established that allow to investigate the atomic structure of crystalline solids quantitatively and almost routinely.
Nevertheless, there are limits to the application of these methods and they are of principle and of practical nature. Obviously, the resolution of quantitative HRTEM is limited by the point resolution of modern microscopes that has reached 0.1 mn. However, the quantification of the information from lattice images requires two important steps, namely, the application of a pattern recognition procedure and the extraction of changes of the electron scattering potential from the lattice images. The application of the pattern recognition procedure influences the lateral resolution of the method because a lattice image has to be broken up into unit cells of identical size (figure 1).
Extraction of Information From Stem-Edx Segregation Profiles Using Multivariate Statistical Analysis
Authors: Titchmarsh J M 
Published: July 2020

Abstract
Multivariate Statistical Analysis (MSA) has been applied to spectroscopic data acquired by various methods but only recently to EDX spectra acquired in the transmission electron microscope where segregation sensitivity was improved by a factor of x2-3. Equilibrium segregation data were ideally suited for MSA analysis. Each spectrum was composed of a linear sum of contributions from the segregation layer and the two adjacent grains or phases, in proportions determined by the probe current distribution and location. MSA successfully identified an eigenvalue explicitly associated with segregation. Smaller eigenvalues related to self-absorption and coherent bremsstrahlung (CB) were also revealed. The use of an orthogonal MSA constrained the information sources to be independent. This constraint, which was reasonable for equilibrium segregation, has now been examined for a more complicated case: thermally and radiation-induced diffusion near an interface where profiles derived by conventional processing have varying features (Fig.l) from which it is difficult to extract real concentration profiles or even qualitative correlations between elements.
Atomic Resolution Electron Energy Loss Spectroscopy of Interfaces
Authors: Pennycook S J , Dickey E C , Wallis DJ , Browning N D , Nellist P D 
Published: July 2020

Abstract
The ability of high resolution STEM instruments to provide EELS data at the ultimate atomic resolution offers significant new insights into interfacial phenomena. Not only can composition profiles now be collected plane-by-plane across an interface, but in addition, the EELS near edge fine structure can be analysed to determine the valence states of atoms at the interface, and hence the nature of the bonding across the interface plane. by applying the spatial difference technique, these effects can be studied quantitatively with high sensitivity.
Atomic resolution EELS played a critical role in explaining a completely unexpected interfacial structure found recently at CdTe/Si interfaces grown by a particular molecular beam epitaxy growth procedure. The high resolution Z-contrast image in Fig. 1 shows the CdTe film to be terminated by Te, but in addition, for several monolayers into the Si substrate, occasional columns show brighter than the surrounding Si, although remaining in the correct position.
Elfs: Energy Loss Fine Structure Analysis in Materials
Authors: Sarikaya Mehmet , Qian Maoxu , Stern Edward A 
Published: July 2020

Abstract
ELFS (energy loss fine structure), similar to XAFS (x-ray absorption fine structure) provides short-range order atomic structural information of crystalline and amorphous materials. Although known quite sometime, ELFS spectroscopy only until recently has gained importance, mainly due new developments in spectrometer and TEM designs, spectra acquisition and interpretation techniques. This paper focuses on some new developments in the acquisition, interpretation, and the use of the extended regime of the ELFS spectroscopy.
Although fine structure spectroscopy in EELS and its similarity to XAFS were recognized sometime ago, ELFS has only seen limited use mainly because of insufficient spectral statistics, various systematic errors and drifts, and the absence of sophisticated software that faithfully uses the XAFS software and incorporates the latest advances in modeling theory. We have systematically improved the data acquisition technique and developed ELFS data analysis procedure which utilizes the sophisticated UWXAFS data analysis software package8 after correction of the differences between ELFS and XAFS data.
Calculation of Electron Energy Loss Near Edge Structure by the Layered Kkr Method
Authors: Rez P , Maclaren JM 
Published: July 2020

Abstract
The analysis of near edge structure on inner shell ionisation edges in electron energy loss spectroscopy (EELS) can lead to new insights on the nature of bonding on an atomic scale. To fully understand the origins of spectral features it is necessary to calculate the near edge structure from a suitable theoretical model. Many of the previously published theories are based on multiple scattering of the ejected electron in a cluster of atoms surrounding the site of the excitation. The techniques used for the selection of scattering paths account for most of the differences between the various theories. In the XANES method the atoms in the vicinity of the excited atom are assigned to coordination shells and a separation is made between scattering within a given shell (intrashell) and scattering between shells (intershell). The FEFF method selects paths up to a given maximum length according to the number of scatterings and estimated amplitude.
Practical Estimation of Analytical Sensitivity for EDS in an Intermediate Voltage FEG-STEM
Authors: Watanabe M , Ackland D W , Williams D B 
Published: July 2020

Abstract
One of the ultimate objectives for energy-dispersive X-ray spectrometry (EDS) in the analytical electron microscope (AEM) is single-atom detection in thin specimens, as well as quantitative microanalysis with high accuracy approaching ±1% relative. In order to realize the single-atom analysis, the design of the AEM has to be optimized with respect to improvements in spatial resolution and detectability limits. The detectability limit, as defined by the minimum mass fraction (MMF), is given by:

where P is the peak intensity of interest, (P/B) is the peak-to-background ratio for that peak, and r is the acquisition time. To improve the sensitivity for analysis, any or all of the variables P, (P/B), and τ should be increased. Intermediate-voltage analytical electron microscopes combined with high brightness field-emission gun (FEG) are expected to improve the MMF, while maintaining high spatial resolution. Additionally, the MMF should also be improved by maximizing the solid angle of X-ray collection.
Energy Filtered Imaging and Convergent Beam Electron Diffraction (CBED) in the Transmission Electron Microscope (TEM)
Authors: Fox AG , Menon ESK , Saunders M 
Published: July 2020

Abstract
Over the last ten years TEMs have been developed that are capable of HREM, EDX, PEELS and diffraction using a single objective pole piece. More recently these TEMs have been equipped with the capability of energy filtering the electron beam after it has passed through the sample so that energy filtered images and electron diffraction patterns can be obtained. In this work the use of a Topcon 002B TEM equipped with a GATAN PEELS imaging filter (GIF) to generate zero-loss energy filtered zone axis CBED patterns and elemental images from inelastically scattered electrons will be described. An analysis of this energy filtered data indicates that elemental imaging using the GIF is an informative, but semiquantitative technique, whereas zero-loss energy filtered zone axis CBED patterns can be accurately quantified so that the two lowest-angle x-ray form factors of cubic elements can be measured with errors of the order of 0.1% or less.
Analysis of Nanometer-Scale Precipitation in a Rapidly Solidified Stainless Steel
Authors: Wisutmethangoon S , Kelly TF , Camus PP , Flinn JE , Larson DJ , Miller MK 
Published: July 2020

Abstract
Though stainless steels are important technologically for a wide range of applications, they are not generally known for their very high strength. We have rapid-solidification-processed many stainless steels by gas atomization and achieved strength improvements of over 50% relative to conventionally-processed stainless steels with concomitant improvement in corrosion and oxidation behavior. These strength improvements are most pronounced after aging treatments when elevated concentrations of oxygen and vanadium are present in the stainless steel. An austenitic (FCC) stainless steel (Fe-16%Ni-9%Cr-0.5%Mn-0.2%V-0.0137%N-0.008%O by weight) was prepared by gas atomization and consolidated by hot extrusion at 900°C. These specimens were heat treated for 1 hour at 1000°C and aged at 600°C for 500 hours.
The microstructure of each alloy composition was observed in TEM with bright field imaging. After aging, most alloys showed the same precipitate morphology as before aging. An obvious change, however, was found only in the alloy with highest oxygen content.
Reactive Gas Plasma Specimen Processing for Use in Microanalysis and Imaging in Analytical Electron Microscopy
Authors: Zaluzec Nestor J , Kestel Bernard J , Henriks David 
Published: July 2020

Abstract
It has long been the bane of analytical electron microscopy (AEM) that the use of focused probes during microanalysis of specimens increases the local rate of hydrocarbon contamination. This is most succinctly observed by the formation of contamination deposits (fig.l) during focused probe work typical of AEM studies. While serving to indicate the location of the electron probe, the contamination obliterates the area of the specimen being analyzed and adversely affects all quantitative microanalysis methodologies. A variety of methods including: UV, electron beam flooding, heating and/or cooling can decrease the rate of contamination, however, none of these methods directly attack the source of specimen borne contamination. Research has shown that reactive gas plasmas may be used to clean both the specimen and stage for AEM, in this study we report on quantitative measurements of the reduction in contamination rates in an AEM as a function of operating conditions and plasma gases.
The Use of a Cold Gas Plasma for the Final Processing of Contamination-Free TEM Specimens
Authors: Fischione PE , Ringnalda J , Feng Y , Krekels T , Colijn HO , Mills MJ , Wiezorek JM 
Published: July 2020

Abstract
The issue of specimen contamination becomes more important at a rate proportional to the use of high-brightness electron source Transmission Electron Microscopes (TEM). These TEMs combine smaller electron probes with increased current, allowing high resolution specimen imaging and enhanced analytical data collection. Small, high current electron probes tend to increase the detrimental effect of hydrocarbon presence on the specimen's surface. The subsequent formation of carbon deposits caused by the focused probe often times obstructs imaging and precludes acceptable analytical results. by plasma cleaning the specimen, contamination is removed and the results obtained by high resolution electron microscopy (HREM), scanning transmission electron microscopy (STEM) and analytical electron microscopy (AEM) using EDS or electron energy loss spectroscopy (EELS) are greatly enhanced. Recent instrumentation developments have resulted in the application of a high frequency, low energy, reactive gas plasma generated in an oil-free vacuum that chemically removes hydrocarbon contamination from both the TEM specimen holder and the specimen without altering its properties.
Determining the 3-Dimensional Structure of Defects in Oxide Materials Using Eels
Authors: Moltaji H , Buban J P , Browning N D 
Published: July 2020

Abstract
Electron energy loss spectroscopy (EELS) is ideally suited for the study of oxide materials. The large cross section for the oxygen K-absorption edge generates enough signal for fine-structure analysis even when the probe is small enough for atomic resolution imaging (∼2Å). Therefore, by using the Z-contrast imaging technique in the STEM to locate defects and position the probe with atomic resolution, detailed spectroscopic information can be obtained from a known atomic location. by selecting the appropriate acquisition conditions, these spectra can have the same atomic resolution and incoherent features as the Z-contrast image. The primary benefit of this methodology is that the image provides a structural model for interpretation of the spectrum through theoretical modeling.
One means of interpreting this spectral fine-structure is through multiple scattering analysis. In the multiple scattering formulation, the fine-structure of the absorption edge is considered to arise from interference effects resulting from the scattering of an excited photoelectron from neighboring atoms.
Martensitic Transformation in a Ti50ni48fe2 Alloy Studied by Eels
Authors: Murakami Y , Shindo D , Oikawa T , Kersker M 
Published: July 2020

Abstract
Martensitic transformation is the first-order diffusionless phase transformation in solids, and is responsible for unique phenomena such as shape memory effect and superelasticity. Recently, many researchers tried to explain the origin of martensitic transformations from a viewpoint of electronic structure. It is strongly required to investigate electronic state changes associated with a martensitic transformation by an accurate experiment. EELS (Electron Energy-Loss Spectroscopy) was successfully applied to study electronic state in several alloys and oxides, e.g. a composition dependence of density-of-state (DOS) in Cu-3d band was clearly observed for Cu1-xAlx alloys by a core-loss measurement. However, this method has been less applied to studies of phase transformations to date. The purpose of the present work is to investigate electronic state changes associated with a martensitic transformation in a Ti50Ni48Fe2 alloy by EELS.
A Ti50Ni48Fe2 alloy was prepared by induction-melting method. Thin-foiled specimens were solution-treated in Ar atmosphere at 1173K for 1hr.,
In-Column Energy Filtering Transmission Electron Microscope (EFTEM) - Integrated Analysis of Energy Loss Signals
Authors: Bauer R , Benner G , Büscher P , Probst W , Seybold V , Zellmann E 
Published: July 2020

Abstract
In an EFTEM the full range of signals generated by interaction of the primary electron beam with the specimen can be detected. Thus operating such a system and generating combined digital information usually is a rather complex issue. The demands of the users on the other hand are to achieve results fast, easily and reproducibly. Moreover it should be possible to tailor the integral system according to dedicated needs. In general it should be no problem to use modern digital equipment and just let an integral computer control everything. However, in order to make such digital settings really useful, there should be no D/A conversion in between the data paths of the microscope because any analogue system tends to drift and the changes of lens parameters between different modes of operation should be minimised to overcome hysteresis. Fully digitised in-column EFTEMs like the LEO EFTEMs with OMEGA filter and Koehler illumination including also multiple parallel and serial remote capabilities provide optimum preconditions to fulfil the demands.
MicroAnalysis of Soot Participates Using STEM
Authors: Bell David C , Rainey Lenore C , Vander-Sande John 
Published: July 2020

Abstract
Overview Scanning transmission electron microscopy (STEM) coupled with energy dispersive x-ray analysis (EDX) and electron energy-loss spectroscopy (EELS) has been used to characterize the elemental composition and oxidation conditions of various soot samples. The STEM employed in this investigation was the Vacuum Generators HB603-MIT, with a microanalyical resolution approaching 1 nm, that allowed the analysis of individual soot particles and aggregates.
The aim of this research is quantification of the EDX spectra which is possible after background and absorption corrections. This information can then be used for comparative studies of different fuels and combustion processes.
EELS has been employed to determine the amount of graphitic carbon in a soot particulate, and the detection of trace elements of low atomic number. It has been shown in soot that for Carbon the energy-loss of the p shell electrons increases with the amount of oxidation at high temperatures.
Analysis and characterization of gas turbine soot, collected from an engine exhaust duct of a 737-300 aircraft showed an abundance of different elements.
Debye-Waller Factor Measurements by Quantitative Convergent Beam Electron Diffraction (CBED)
Authors: Saunders M , Fox A G , Midgley P A 
Published: July 2020

Abstract
Quantitative CBED techniques are now capable of making low-order structure factor measure-ments with sufficient accuracy to study bonding effects in crystalline materials. The main limitation of these techniques has been identified as the accuracy with which one knows the Debye-Waller factor(s) (DWF(s)). Even where X-ray measurements exist, values have usually been determined at room temperature whereas we often want to perform our electron diffraction experiments at liquid nitrogen temperatures to reduce the effects of thermal diffuse scattering (TDS). Attempts to calculate theoretical DWF values have been shown to have limited accuracy when compared to experimental measurements.
This has led to a search for new electron diffraction methods for DWF determination such as the use of HOLZ line segments, high-index systematic rows and electron precession patterns. The aim should be to measure the DWF(s) under identical conditions to those used for the charge density studies, e.g. the same sample thickness, temperature and microscope settings.
Maximum Entropy and Bayesian Methods of Solving the Phase Problem in Electron Diffraction
Authors: Gilmore CJ 
Published: July 2020

Abstract
The phasing of electron diffraction data poses considerable problems for traditional direct or heavy atom crystallographic methods since the data are incomplete or at less than atomic resolution (i.e. 1.1Å), and subject to errors arising from dynamical scattering effects. The Bricogne formalism for phasing diffraction data using maximum entropy (ME) and Bayesian methods has proved especially useful in these situations1 since this formalism is stable irrespective of data resolution and completeness, and is robust with respect to errors on the measured diffraction intensities.
Successes with this formalism this include a wide range of structures: (1)The ab initio phasing of diketopiperazine C4H6N2O2 (Fig 1).(2)The structure solution of CuCl2.3Cu(OH)2 (Fig 2).(3)The ab initio phasing of two 2-D membrane data sets at ca. 6Å resolution without the use of image phases (Halorhodopsin and Omp F Porin4 - Figs 3 and 4). In addition, we have had some success in phasing the 3-D data of bacteriorhodopsin at 6Å.
The Use of Phase and Amplitude Information of Reconstructed Exit Waves
Authors: Zandbergen HW 
Published: July 2020

Abstract
Exit waves can be reconstructed from through focus series of HREM images or by off-axis holography [1]. We have applied the through focus method to reconstruct exit waves, using algorithms developed by Van Dyck and Coene [2]. Electron microscopy was performed with a Philips CM30ST electron microscope with a field emission gun operated at 300 kV. The high resolution images were recorded using a Tietz software package and a 1024x1024 pixel Photometrix CCD camera having a dynamic range of 12 bits. The reconstructions were done using 15-20 images with focus increments of 5.2 nm. The resulting exit waves were corrected posteriorly for the three fold astigmatism.
The exit wave is complex; consequently it contains phase and amplitude. Since in the very thin regions the specimen acts as a thin phase object, such a thin area will show little contrast, an example of which is shown in Figure 1.
3-D Structure of a Water Channel At ˜6Å Resolution as Determined by Electron Crystallography
Authors: Jap BK , Li H-L , Lee S 
Published: July 2020

Abstract
Aquaporin-1 (AQP1) is a class of water channels within the aquaporin superfamily. These channel proteins have been found in a wide variety of tissues such as kidney, lung, eye secretory gland and intestinal epithelium as well as in vacuolar membranes of plants. The major function of these channel proteins is to transport water exclusively into and out of cells. Based on amino acid sequence, it has been predicted that aquaporins contain six lipid bilayer-spanning a-helices. Models for the molecular folding of AQP1 containing six and four transmembrane a-helices have been proposed previously. Our earlier projection map at 3.5Å resolution revealed eight high density peaks which we interpreted as the projections of seven transmembrane α-helices and an eighth possibly transmembrane segment. The juxtaposition of structures seen in the projection map prevented us from unambiguously determining the exact number of transmembrane helices based on the projection map alone. We report here the three-dimensional (3-D) map at ˜6 Å resolution as determined by electron crystallography.