bluuebunny/crossref_metadata_2025_split huggingface dataset:
Physical Considerations in Low Energy Biological Analysis
Authors: Joy David C 
Published: July 2020

Abstract
Biological scanning electron microscopy is increasingly performed at low beam energies in order to improve image contrast, reduce charging artifacts, and minimize beam induced damage to the sample. It is natural then to wish to also use these same low accelerating voltage for X-ray microanalysis using an energy dispersive spectrometer (EDS) but a variety of fundamental physical effects affect the performance that can be achieved. An X-ray photon can only be emitted when the incident beam Eo energy exceeds the critical excitation energy Ecrit for that line. As the beam energy is reduced the number of elements that can be excited falls and it is becomes necessary to use L- and M-lines rather than the K-lines accessible at higher energies. At 5keV, the upper limit of ‘low voltage’ microscopy, K-lines can be excited from elements up to calcium, L-lines can be detected up to cesium, and the rest of the periodic table is available using M-lines. The entire periodic table is therefore, in principle, available at an overvoltage U&gt;2, where U = E0/Ecrit But at lower energies the number of accessible excitations falls and some elements cannot, with current technology, then be analyzed and for general purposes an incident energy lower than about 3keV is probably too limiting to be useful.
Microcalorimeter Energy Dispersive Spectrometry for Low Voltage SEM
Authors: Wollman D A , Newbury Dale E , Hilton G C , Irwin K D , Rudman D A , Dulcie L L , Bergren N F , Martinis John M 
Published: July 2020

Abstract
Microanalysis performed at low electron beam energies (≤ 5 keV) is limited by the physics of x-ray generation and the performance of existing semiconductor energy dispersive spectrometry (EDS) and wavelength dispersive spectrometry (WDS). Low beam energy restricts the atomic shells that can be excited for elements of intermediate and high atomic number, forcing the analyst to consider using unconventional M- and N-shells for elements such as Sn and Au. Unfortunately, these shells have very low fluorescent yield, which results in inherently low spectral peak-to-background ratios. The modest energy resolution of semiconductor EDS leads to poor limits of detection for these weakly emitted photons. The situation is further complicated by the inevitable interferences with the much more strongly excited K-shell x-rays of the light elements, particularly carbon and oxygen. WDS has the spectral resolution to overcome the resolution limitations of semiconductor EDS. However, WDS has a low geometric efficiency, and because of its narrow instantaneous spectral transmission, spectral scanning is required to detect and analyze x-ray peaks. Moreover, the high resolution field-emission-gun scanning electron microscope (FEG-SEM) provides only a few nanoamperes of beam current.
On the Contrast of Precipitates Observed with a FE-SEM
Authors: Gauvin Raynald , Hovington Pierre 
Published: July 2020

Abstract
It has been shown recently that precipitates as small as 10 nm can be imaged with a FE-SEM using a Through-The-Lens (TTL) SE detector or the so-called Upper Detector (UD). This is a very significant finding because normally, such small precipitates are observed in the TEM where specimen preparation techniques are generally a timely process. However, from Monte Carlo simulations using CASINO, it has been shown that NbC precipitates embedded in Fe as small than 6 nm can be imaged with BE. The experimental demonstration was difficult because no good BSE detectors were available at that time for low energy work.
Recently, a new BSE detector has been developed for low energy work from the GW corporation, the Centaurus BSE detector. This detector is coupled with an HITACHI S-4700 FESEM In this work, images of Mg2Zn precipitates in Al obtained with the UD and the Centaurus BSE detector are compared.
Quantitative Chemical Mapping with Low-Voltage EDS Spectrum Imaging and Multivariate Statistical Analysis (MSA)
Authors: Anderson IM 
Published: July 2020

Abstract
One of the advantages of performing X-ray microanalysis at low (≤5 kV) operating voltages is that high spatial resolution (≤250 nm) chemical maps of the specimen can be acquired. Spectrum imaging, where a full spectrum is acquired for each pixel in a two-dimensional array, provides the most comprehensive method of characterization, as long as the sampling density (pixel size) is sufficiently smaller than the spatial resolution. Multivariate statistical analysis (MSA) methods are effective in reducing the large (typically ∼10 MByte) raw spectrum images to the modest (typically ∼100 kByte) data files that contain all of the statistically significant information of interest about the specimen. Preliminary analysis of a cross section of a computer chip from a major semiconductor company was previously performed using limited spectrum imaging capabilities available with the 4pi X-ray mapping module, which allowed for simultaneous acquisition of only 48 channels. MSA of images acquired with only a 960 eV portion of the spectrum containing the Al-K, Si-K and W-M lines showed that excellent contrast between the Si- and W-rich regions of the specimen could be achieved in spite of the strong overlap between Si-Kα and W-Mα (∼34 eV separation).
Imaging Self-Assembled Monolayers: a Comparative Study Between AFM and Field-Emission SEM
Authors: Russell PE , Neves BRA , Salmon M E , Troughton EB 
Published: July 2020

Abstract
Self-assembled monolayers (SAM) and multilayers of organic materials have been intensely studied in the past years, due to their numerous potential applications as, for example, lubricants, corrosioninhibitors and/or adhesion-promoters [1,2]. Due to the reduced height of SAM, typically a couple of nanometers, the various Scanning Probe Microscopy (SPM) techniques, especially Scanning Tunneling Microscopy (STM) and Atomic Force Microscopy (AFM), have been the tools of choice in the morphological and structural study of those systems [1,2]. However, these SPM techniques have some limitations. One of them is the reduced scanning area, preventing the assessment of SAM coverage in large substrate areas, which is one of the key issues in studies of the potential applicability of SAM. Furthermore, due to their imaging principle, the SPM techniques are not suited to analyze SAM on substrates where the roughness is of the order of hundreds of nanometers or higher, impeding their application on most non-ideal (atomically flat) substrates.
Scanning Electron Microscopic Analysis of Fossil Bone (Mosasaurs) from Marine Deposits of the Upper Cretaceous of North America
Authors: Amy Sheldon M 
Published: July 2020

Abstract
Research into bone histology of fossil material is a growing area of inquiry in vertebrate paleontology. Incorporating histological study into ontogenetic investigation presents new opportunities for gaining data to better understand ontogeny, ecology, and evolution of mosasaurs. Adding scanning electron microscopy to the growing technology being applied to fossil research can only further the understanding of long extinct animals.
Mosasaurs were totally marine lizards which inhabited both open ocean and epicontinental seas during the late Cretaceous (Turonian through Maestrichtian), approximately 90-65. million years ago. Mosasaurs have been collected from many areas of North America. The specimens used in this study were collected from Alabama, Kansas, South Dakota, and Texas. I have restricted the fossil material for destructive analysis to ribs and vertebrae. Ribs have not been shown to have importance in morphological analysis relating to systematics or evolution, therefore their destruction does not imped the research of others. Vertebrae were isolated on outcrop but could be identified to genus and growth stage.
Displacement Mapping During In-Situ Straining in the SEM
Authors: Biery Nicholas E , Pollock Tresa M , Nuhfer NT , Graef Marc De 
Published: July 2020

Abstract
We have developed a technique for measuring small strains during in-situ tensile tests in a Scanning Electron Microscope (SEM). The technique uses pattern recognition algorithms to locate markers on a gridded sample before and after deformation. The distortions in the grid are used to calculate the strains at each of the markers. The strains are then displayed in contour plots and correlated with the microstructure of the sample to help understand the local progression of strain as a function of applied load and microstructure.
Tensile experiments were performed on gridded notched and unnotched samples of a Ti-48Al-2Cr- 2Nb alloy (at%) in a Philips XL-30 FEGSEM using a 10,000 N Kamrath-Weiss in-situ straining stage. Gold was evaporated onto the samples through nickel grids with a mesh size of 17 μm. Electron backscatter images of the samples taken during testing were analyzed using a set of, interactive routines written in the Interactive Data Language (IDL).
Omega Filter design for a 200kv TEM
Authors: Tsuno K , Kaneyama T , Honda T , Ishida Y , Munro E , Rouse J 
Published: July 2020

Abstract
A new omega filter has successfully been installed in 200kV TEMs(see FIG. 1). Energy filtering TEM (EFTEM) is extremely useful to enhance contrast of biological specimens, to observe defects in thick semiconductor tips, to obtain a good compositional map in grain boundaries, to give structure image in the thick specimen regions and to obtain quantitative data by removing plasmon loss signals. In-column filters such as omega filter has advantages over postcolumn filters from points of cancellation of aberrations, to obtain iso-chromatic images and a freedom of selecting variety of magnifications.
Here, we discuss conditions of designing an omega filter. In usually, curved axis systems, which are common to energy analysis equipment, has large second order aberrations. Those aberrations are compensated in analyzers with single sector magnet with multi stage sextupole correctors. However, the adjustment of those correctors is difficult and residual aberrations destroy quality of the filtered image.
Modification of an Energy Filtering Transmission Electron Microscope for Low Energy Loss Imaging and Chromophore Mapping
Authors: Davis J A , Heng Y M , Barfels M M G , Ottensmeyerf F P 
Published: July 2020

Abstract
We have recently replaced the electron energy filter of the Zeiss EM 902 with an improved PMP filter. The design, incorporating concave curved entrance and exit faces and convex curves on the side facing the electrostatic mirror was based on the theoretical calculations of Jiang and Ottensmeyer and Barfels et al. Care was taken in the design of the filter to allow its introduction into the existing geometry of the microscope and its use of the existing electronics. As a result, dismantling the existing prism housing and support (which were used as the base for the new prism), reinstallation, and adjustment required only three working days. The resolution in tjie energy dispersive plane of the new filter was measured using the 15.0 eV plasmon peak of aluminum as an internal standard. Such measurements yielded a FWHM of 1.1 eV over the full image plane (fig. 1) with an optimum resolution of approximately 0.8 eV possible with corrections to the stability of the voltage supply and further small alignment adjustments.
This improved energy resolution permits the detection and imaging of signals in the low loss region previously inaccessible to us in the EM902.
Improving the Positional Accuracy of the Goniometer on the Philips CM200 TEM.
Authors: Pulokas J , Green C , Kisseberth N , Potter CS , Carragher B 
Published: July 2020

Abstract
We have developed a system (1) for automatically acquiring large numbers of high quality transmission electron micrographs under low dose conditions. This system has been implemented on a Philips CM200 Transmission Electron Microscope equipped with a Gatan MSC CCD camera. Implementing the automated data acquisition system requires that target locations be identified in a low magnification image and then accurately located at the center of the viewing area. The magnification is subsequently increased, the image is focused on an area adjacent to the target area and the final image is acquired. Centering an identified target location for subsequent high magnification imaging typically requires moving the specimen by many thousands of nm and accurately locating the target to within a few hundred nm. This movement is too large to be achieved using the image shift coils, which would be very accurate, and instead must be achieved using the goniometer.
We have measured the accuracy of the goniometer on the Philips CM200 and the results are shown in fig 1. Data were obtained by selecting a target area from a low magnification image [660x], moving to this target and then measuring the accuracy of the requested movement by cross correlation.
Evaluation of Low Noise Objective Lenses for Detection of Weak Fluorescence
Authors: Nakano Yoshitaro , Sase Ichiro 
Published: July 2020

Abstract
The optimal method for evaluating fluorescence microscope has not been proposed. In this study we developed two quantitative methods using biological and non-biological materials as standard specimens. Based on these methods, a new water immersion lens was tested and its high sensitivity to fluorescence was demonstrated.
First, particles of a fluorescent glass (Luminass-1; Sumita Optical Glass) were used for the standard specimen. Particles with a few micrometer diameter were embedded in silicon oil on a quartz slide glass covered with a quartz glass slip and then observed. Under the fluorescence microscope, the spectra of emission light from the excited area with or without the particle were measured by a monochromator and a photomultiplier tube (PMT). The signal-to-background ratio (S/B) was calculated from these spectra (Fig. 1, Table 1). This specimen showed a significant advantage due to less photobleaching that permits a stable and long observation time.
Parallel Auger Spectroscopy with the Hyperbolic Field Analyser
Authors: Jacka M , Kirk M , El Gomati M , Prutton M 
Published: July 2020

Abstract
The analysis of Auger and other excited electrons in the energy range from about 50eV to 2500eV provides a nearly non-destructive means to determine the surface composition of materials. It is both highly surface sensitive (a few atomic monolayers) and capable of high spatial resolution. This makes it an attractive alternative to energy dispersive x-ray analysis for the examination of ever smaller structures such as in semiconductor devices. For many applications however one important drawback has been the relatively long time required to make useful measurements - usually many seconds or minutes. Spectrum-imaging, in which an entire spectrum is acquired for each pixel in a digital scanned image, is one example for which Auger, spectroscopy becomes a prohibitively lengthy process. Similarly, the study of electron beam sensitive materials is difficult because the measurement time is often longer than the damage time. One method of reducing the measurement time is by acquiring the whole energy spectrum of interest in parallel. This is achieved with the Hyperbolic Field Analyser. (In electron energy loss spectroscopy this approach has lead to the highly successful Gatan energy filter.)
Real-Time Full Motion Stereo Microscopy Over Internet
Authors: Case Gary N , Vouk Mladen A , Mackenzie John M 
Published: July 2020

Abstract
One of the problems with remote imaging which purports to represent the real world (Tele-presence) is that the images are two-dimensional and the “real” world is three dimensional. When viewing many objects, the lack of depth perceptiorican be a serious deficiency. For example, one would want a micro-surgeon to have a good idea how deep to cut into tissue during a tele-presence operation. There is a wealth of three dimensional information in light, SEM, AFM, confocal, and computer reconstructed or simulated objects. To transfer that information faithfully over the networks using broadcast quality high definition video transmission technologies such as MPEG2 may require as much as 20 Mbps per channel. Furthermore, stereo imaging is particularly sensitive to any phase delays and jitter between the two eye channels. Control of these parameters requires advance quality of service features that current internet does not provide, but that may be available on high-performance intranets. All this may present a problem for routine use of the stereo facility.
The next generation of Internet, however, will be able to routinely provision much higher bandwidth and other quality of service, in general through protocols that will allow for not only full screen full resolution television but also the use of two channels (left and right) that can stay in fairly close synchrony.
A Stacked CMOS Active Pixel Image Sensor for Charge Particle Detection and the Application to SIMS
Authors: Yurimoto H , Nagashima K , Kunihiro T , Takayanagi I , Nakamura J , Kosaka K 
Published: July 2020

Abstract
A stacked CMOS active pixel image-sensor (APS) has been developed for detecting various kinds of charged particles and its noise performance has been measured and analyzed. The sensitivity for ions and electrons with keV energy level utilizes for ion microscopy such-as SIMS and electron microscopy, respectively.
Charge particles such as ions and electrons with kinetic energy of keV order are useful probes for surface analysis of material. A measurement system which yields two-dimensional image of charge particles is highly demanded. The conventional two-dimensional detection system is composed of a micro channel plate, a florescent plate which receives multiplied secondary electrons and generates a visible image, and a visible image sensor. However, its limited dynamic range and non-linearity in the ion-electron-to-photon conversion process make a quantitative measurement difficult. The proposed system using a stacked CMOS APS has several advantages over the conventional system such as high spatial resolution, no insensitive time, high S/N, wide dynamic range, nondestructive readout capability, high robustness, and low power consumption.
3-D Reconstruction of Thick IVEM Samples Using Tuned Aperture Computed Tomography
Authors: Gray Jerome W , Grant Ken , Al Gailany A M , Yancey Patricia G , Betterman Wolfram , Webber Richard 
Published: July 2020

Abstract
The development of high and intermediate voltage electron microscopes provides the ability to investigate the ultrastructure of thick biological samples. This produces a unique view of the 3-D interrelationships of cells and organelles. However, the analysis and display of this 3-D information has presented challenges, particularly to quantitative biologists. Major advances in adapting computed tomography (CT) to electron microscopy have provided the major means of 3-D analysis of cellular ultrastructure (1,2). In particular, tremendous gains in determining the structure of macromolecules have occurred with advances in electron microscopy CT (3). However, CT remains an arduous undertaking and one not well suited to analysis of the structural alterations within large populations of cells requiring many reconstructions. We have adapted an alternative approach, Tuned Aperture Computer Tomography (TACT®), for use with high and intermediate voltage electron microscopes. Although with EM specimens TACT® does not usually produce as high Z axis resolution as CT, the simplicity of the TACT® algorithms lend themselves to the rapid analysis of multiple samples. TACT® is already gaining acceptance in radiology (4, 5). Like CT, TACT® uses a series of images of the sample taken from different angular perspectives. However, unlike CT, for TACT® only a few projections are required and thus good reconstructions of beam sensitive material are possible. The quality of the reconstruction is determined by the quality of the input images, the total angular spread, and the individual tilt increments between images. Better images, a greater angular spread, and smaller angles between images will produce more accurate results.
Novel High Resolution Measurement of Bone Mineralite Size and Shape
Authors: Eppell S J , Tong W , Katz J L , Kuhn-Spearing L , Glimcher M J 
Published: July 2020

Abstract
Study of the microscopic structure of bone dates back to the earliest use of the optical microscope. Understanding the complexities of the structure of this material has roughly paralleled advances in microscopic technique. Relatively recently a new powerful microscopic technique, atomic force microscopy (AFM), has been invented. So it should not be surprising to expect a new step in our understanding of bone. There have been several recent publications applying AFM to bone and its constituents. None of these studies have examined the shape of naturally occurring mineralites in bone. The issue we addsgss in this work is the elucidation of the three dimensional structure of the apatite mineralites in bone. Chiefly, two methods have been used previously to ascertain this structure: transmission electron microscopy (TEM) and X-ray diffraction (XRD,). The major difficulty with TEM is that it is a projection technique. Each image only yields information about geometry in a single plane. Landis et al. showed how to circumvent this problem using tomographic TEM. AFM provides a corroborative and perhaps more gentle method of directly measuring the structure of very small bone mineralites. It is possible that the interaction energy of the electron beam with very small mineralites is sufficient to vaporize them. The problem with XRD is that the line broadening used can have contributions from sources not directly related to mineralite size. In particular, if a single mineralite contains more than one crystalline domain, then the line broadening yields a measure of the domain size, not the overall mineralite size.
Early Stages of Bone Bonding to HA-Coated Prostheses
Authors: Porter Alexandra , Benezra Valarie , Spector Myron , Hobbs Linn W 
Published: July 2020

Abstract
The need to optimize adhesion between the femoral stem and the surrounding tissue has led to the development of plasma sprayed HA-coated implants as attachment veichles for hip prostheses. The strength of attachment of bone to the HA surface cannot be fully explained by mechanical bonding at the macroscopic or microscopic level; thus, molecular interactions must contribute significantly to bone bonding, facilitating adhesion at the nanometer level. Observations of apatite crystallites and cell adhesion proteins in the direct vicinity of coated implants indicates that these play a role in modifying the surface for osteoblast attachment and subsequent collagen deposition.
An understanding of the mechanism of “bone bonding” could lead to improvements in the design of HA coatings, leading to enhanced performance of orthopedic implants. Transmission electron microscopy (TEM) has been used to elucidate a sequence of early bone bonding events at the interface of PSHA-coated titanium implants.
The deposition of biological apatite and subsequent formation of a bone/HA bond seem to depend on the dissolution of the coating and the reprecipitation of carbonated apatite. Previous investigations in vitro have shown that the degree of dissolution and reprecipitation decreases as the coating crystallinity increases. Thus, coatings which had undergone heat treatment were used to look at the effect of solubility of the coating on mechanism of bone bonding.