bluuebunny/crossref_metadata_2025_split huggingface dataset:
Propagation of Errors in the Precision and Accuracy of Quantitative Electron Microbeam Analysis
Authors: Armstrong J T 
Published: July 2020

Abstract
A common question, but one typically difficult to answer, is “How accurate is a microprobe or SEM analysis?” Commercial software for most EDS and WDS systems print out error limits that are typically calculated standard deviations using Gaussian counting statistics based on the accumulated peak and background counts. This is not a true measure of even the measurement precision, since random instrumental instabilities typically degrade “true” measurement precision (as determined by replicate measurements on standards) to 1.5 - 3+ times that predicted from Gaussian statistics. in addition to these random instrumental variations are a plethora of possible systematic and semirandom errors such as detector or faraday cup non-linearities, errors in estimation of background, EDS spectral deconvolution errors, WDS positional non-reproducibility, temperature and pressure variation effects on spectrometer efficiencies, high voltage drift or sample charging, surface contamination or oxidation, and sample roughness or tilt.
Ionization Cross Sections for Quantitative Electron Probe Microanalysis
Authors: Merlet C , Llovet X , Segui S , Fernández-Varea JM , Salvat F 
Published: July 2020

Abstract
Quantitative procedures in electron probe microanalysis (EPMA) require the knowledge of various atomic parameters, the most fundamental of which is the ionization cross section. A number of semi-empirical, approximate analytical formulas have been proposed to calculate the ionization cross section. The simplicity of these formulas makes them suitable for quantitative EPMA procedures. However, it is difficult to assess their reliability because of the lack of accurate experimental data. Indeed, inspection of currently available data reveals that they are still scarce for many elements and, when they are available, one usually finds significant discrepancies between data from different authors. Fortunately, the inaccuracies in the semi-empirical cross section formulas used in EPMA have only a small effect on the analytical results when standards are used. Nonetheless, in quantitative EPMA studies at low overvoltages or using standardless methods, the evaluated compositions largely depend on the adopted ionization cross sections and, therefore, knowledge of accurate ionization cross sections is a requisite for the development of improved quantification methods.
X Ray Spectra Simulation For Wds : Application to Electron Microprobe Automation
Authors: Fournier C , Staub P-F , Merlet C 
Published: July 2020

Abstract
Experimental conditions and setting up of an electron microprobe is directly linked to the assumption or the knowledge that can make the operator on the results of the measurements. Consequently, there is an increasing interest in modelling the X-ray spectrum in order to predict accurately and rapidly the response of the microprobe when a sample of approximately known composition is submitted to specific excitation conditions. Even if the spectra simulation is a current tool proposed in EDS, it always remains a challenge to create a complete absolute WDS spectrum. Indeed, the definition of the efficiency function was a limit to the calculation of absolute intensities.
In this work, we propose a new generation software for EPMA which uses the absolute simulation spectra to assist the operator in the choices of experimental conditions to achieve accurate measurements in a short time as well as to create new functionalities.
Application of Alpha-Factor and Monte Carlo Methods to Epma in the System Ge-Si
Authors: Carpenter P , Cobb SD 
Published: July 2020

Abstract
Terrestrial experiments involving detached growth of GeSi crystals by the Bridgman technique have been performed in preparation for microgravity experiments to be conducted on the International Space Station. These experiments typically produce large GeSi crystals that are sectioned for microscopy, microprobe analysis, and electron-backscatter diffraction analysis. Accurate microanalysis of these crystals is essential for feedback to further growth experiments, but is problematic as the Ge-Si binary exhibits continuous solid solution and it is therefore difficult to prepare homogeneous intermediate standards. There are no experimental measurements on standards of known composition in the Ge-Si binary that could be used to evaluate analytical accuracy. The accuracy of analysis in mineral, oxide, and semiconductor systems has previously been studied using experimental x-ray intensity measurements, correction algorithms and their derived α-factors, and mass absorption coefficient data sets. This study continues that approach and includes results of Monte Carlo calculations in the Ge-Si binary.
Applications of Monte Carlo Simulation of Electron Scattering to Quantitative X-Ray Microanalyses
Authors: Murata Kenji , Yasuda Masaaki , Yamauchi Syunji 
Published: July 2020

Abstract
Monte Carlo simulation of electron scattering has been widely used in various fields such as microanalysis, microscopy and microlithography. Various simulation models have been reported so far. in applications to quantitative x-ray microanalysis the accuracy of the model has been significantly improved by introducing the Mott cross section. However, in the analyses at low energies of an electron beam or at energies near the x-ray excitation energy, the simulation accuracy becomes worse. This is probably because the discrete energy loss process is not incorporated into the simulation model. to improve this default, we developed the model which includes the discrete energy loss process[l]. The outline of the model is described in the following.
1) Elastic scattering
We used the Mott cross section. The Mott cross sections for Al, Cu, Ag and Au elements are calculated at various energies. From this data base we obtain the differential elastic scattering cross section and the total elastic cross section for arbitarary elements and energies by using the interporation or the extrapolation.
Effects of Charging on Quantitative X-Ray Microanalysis Procedures in Environmental / Variable Pressure SEM
Authors: Griffin Brendan J , Suvorova Alexandra A 
Published: July 2020

Abstract
In variable pressure (VPSEM) and environmental SEM (ESEM) caution is required in the intepretation of x-ray data from non-conductive and electrically isolated samples for unique reasons. This paper reviews the documented procedures and presents data on hither-to undefined aspects.
The most widely recognised artefacts are associated with the scatter of primary electrons from their convergent trajectory to the sample surface through interactions with the chamber gas. Beam ‘skirt’ measurements have been made by various researchers and this scatter is well characterised. “Point” analyses are corrupted by addition of components from the surrounding phases and x-ray maps are effectively ‘defocussed’ or ‘blurred’. The magnitude is a function of pressure, amongst many other variables, and it has been shown that these scatter effects can be reduced through extrapolation of data collected at differing chamber pressures2. Bremsstrahlung-based corrections for primary beam variations and drift have also been shown to be effective.
X-Ray Microanalysis of Human Erythrocytes Artificially Jetted Through Tubes At Different Pressures by “in vitro Cryotechnique”
Authors: Fujii Y , Terada N , Baba T , Ueda H , Ohno S 
Published: July 2020

Abstract
It is well known that flowing erythrocytes in blood capillaries were morphologically changing in vivo, as observed by light microscopy. Recently, dynamic morphological changes of flowing mouse erythrocytes in large blood vessels and hepatic sinusoids were demonstrated by scanning (SEM) or transmission (TEM) electron microscopy with our “in vivo cryotechnique”. Moreover, human erythrocyte deformability was already studied under artificially jetting conditions at different pressures by using “in vivo cryotechnique”, followed by freeze-substitution method for SEM. in this study, we have analyzed elemental changes of each human erythrocyte at different jetting pressures by “in vivo cryotechnique” combined with SEM for X-ray microanalysis.
Human blood was collected with heparin-coated syringes, divided into two groups and kept at 4°C and 36°C. They were directly jetted into isopentane-propane cryogen (-193°C) through tubes (21 gauge) at different pressures (0-220mmHg) (Fig.la). The frozen blood samples were freeze-dried (4-6×10-7torr,-95°C,24h) in Eiko FD-3AS apparatus (Eiko Engineering, Japan) (Fig. lb).
A Pre-Golgi Copartment Connecting Golgi Cisterns to the Perinuclear Space in Bovine Herpesvirus 1 (Bhv-1) Infected Mdbk Cells. Evidence for an Intracisternal Pathway
Authors: Wild P , Schraner EM , Cantieni D , Engels M , Loepfe E , Walther P , Müller M 
Published: July 2020

Abstract
The nucleocapsid of herpesviruses is assembled within the nucleus and transported to the perinuclear space by budding through the inner nuclear membrane. The route from the perinuclear space to the plasma membrane for exocytotic release is assumed to involve loss of the acquired envelope by fusion with the outer nuclear membrane followed by wrapping of the nucleocapsid by Golgi membranes. Alternatively, virions are thought to leave the perinuclear space via vacuoles originating from the outer nuclear membrane. Non of these processes has been shown so far. We thus examined the nuclear periphery of MDBK cells infected with BHV-1 by cryobased electron microscopy. Infected cells were high-pressure frozen at 4, 5 and 6 hours of incubation, and freezesubstituted employing a protocol yielding high resolution of membranes.
Thin sections stained with uranyl acetate and lead citrate showed 3 distinct stages of viral envelopment at any time of incubation.
Ultrastructural and Cytochemical Analyses of the Expression of the Thiobacillus Carboxysome Operon in Escherichia Coli
Authors: Aldrich HC , Elvington S , Machines HE , Szabady R , Feder K , McDowell L , Shively JM 
Published: July 2020

Abstract
The cytoplasm of the bacterium Thiobacillus neapolitanus contains 117 nm diameter polyhedral inclusions, “carboxysomes” (Fig. 1) that contain ribulose-1,5- bisphosphate carboxylase/oxygenase (RuBisCO). Surrounding the polyhedron are nonmembranous proteinaceous plates devoid of lipid. The carboxysomes are composed of at least 8 major peptides, all coded within the same operon. Six (CsoSIA, CsoSIB, CsoSIC, CsoS2A, CsoS2B, and CsoS3) make up the shell, and two are the large (CbbL) and small subunits (CbbS) of RuBisCO. Using immunogold labeling on ultrathin sections, peptides CsoS2A, CsoS2B, and CsoS3 have been localized to the shell. Since the original characterization of the csoSl gene, we have also immunolocalized the CsoSl peptide to the shell.
As part of our initial efforts to understand how these components are assembled into the symmetrical, functional entity, the carboxysome operon from T. neapolitanus was cloned into the pET-21a(+) plasmid, an expression vector that codes for resistance to ampicillin.
A New Smaller Sized Virus-Like Particle in Drosophila Melanogaster
Authors: Ault Jeffrey G , Shimakawa Ellen 
Published: July 2020

Abstract
During a chromosome behavior study involving high-pressure freezing (HPF)/freeze substitution (FS) of Drosophila melanogaster testes, we discovered quasi-crystalline inclusions in the nuclei of adjacent gut epithelial cells (Fig. 1). The HPF and FS protocols were standard. The viscera of adult flies were packed in yeast paste for HPF. The tissue was fixed by FS with 1% osmium tetroxide in acetone for 72 hours at -90° C then 48 hours at -60° C. Afterwards, it was washed several times at room temperature in 100% acetone and embedded in Epon/Araldite. Thin sections were cut and stained with uranyl acetate and lead. As expected with HPF/FS, the material was well-preserved with straight microtubules, smooth membranes, dense mitochondria, and abundant ribosomes both on the rough endoplasmic reticulum and in the full cytoplasm (Fig. 1).
The inclusions consisted of virus-like particles packed loosely together in orderly arrays. Particles were usually hexagonally packed with spaces disrupting the periodicity (Figs. 2 and 3).
The Structure of Ppv0l, A Marine Algal Virus with a T=219 Capsid
Authors: Yan X , Chipman P , Castberg T , Bratbak G , Baker T S 
Published: July 2020

Abstract
Phaeocystispouchetii virus (PpV0l), first isolated from Norwegian coastal water in 1995, infects and lyses the haptophyte Phaeocystis pouchetii Lagerheim. PpV0l has not yet been assigned to a family. Phaeocystis may play an important role in ocean climate control and PpV0l infection could alter the amount of this haptophyte. The virion contains a dsDNA genome (∼450 kbps) encapsulated within a large icosahedral shell. The most abundant protein has a mass of 59 kDa. More than five minor polypeptides with masses ranging from 30 to 50 kDa have also been identified. We have used cryo-electron microscopy (cryo-EM) and three-dimensional (3D) image reconstruction methods to examine the native morphology of PpV0l.
Purified PpV0l samples were prepared for Cryo-EM as described. Images were recorded on film at 33,000x nominal magnification in a Philips CM300 FEG microscope at 300kV, at 1.0μm to 2.0μm under focus, and with an electron dose of 2200e-/nm2 (Fig. 1A).
Detecting Herpesvirus By Negative Contrast Electon Microscopy in Tissue and Cell Culture From Mule Deer with Infectious Keratoconjunctivitis
Authors: Hearne CE , Cavender JL , Williams ES 
Published: July 2020

Abstract
Mule deer are infected with a herpesvirus associated with acute infectious keratoconjunctivitis (IKC) or “pink eye”. in December 2000, many young male mule deer in Wyoming had clinical signs of IKC including corneal edema, mucopuvulent conjuctivitis, blepharospasm, and blindness.
Conjunctival swab samples from 5 mule deer with IKC were processed for negative contrast electron microscopy (NCEM) at the Wyoming State Veterinary Laboratory (WSVL). Homogenized samples from each deer were centrifuged for 20 minutes at 3440g in a Beckman Avanti J-25 centrifuge (Beckman Instruments Inc., Fullerton, CA, USA). The supernatant from each sample was subsequently centrifuged for 60 minutes at 39,800g. The final pellet was resuspended in 210 μl of sterile deionized microfiltered water. 105 μ1 of the virus suspension was mixed with sodium phosphotungstic acid stain containing 84 μl of 4% aqueous phoshotungstic acid, pH 6.8 with NaOH, 420 μl sterile, deionized microfiltered water, and 21 μl 0.1% bovine serum albumin.
Blomineral Compartmentalization in Uncultured Magnetic Bacteria
Authors: Lins Ulysses , Keim Carolina N , Farina Marcos 
Published: July 2020

Abstract
Magnetic bacteria are a group of motile microorganisms that orient to magnetic field lines because of membrane-bound organelles called magnetosomes. Magnetic bacteria precipitate magnetite (Fe3O4) or greigite (Fe3S4) in their magnetosomes. The ability of uncultured magnetic bacteria of accumulating minerals in different cell compartments is still poorly understood. We have been studying natural enrichments of magnetic bacteria from the Itaipu and Rodrigo de Freitas lagoons, in Rio de Janeiro, Brazil. Here, we have used energy-filtering transmission electron microscopy to study the element distribution in biocomposites found in magnetic bacteria from both lagoons. in Itaipu lagoon, electron microscopy and phylogenetic position determination by 16S rRNA genes sequencing identified at least four morphotypes of magnetic bacteria. Typical structures found in all gram-negative bacteria, in addition to some internal compartments were observed (Fig. la). Amorphous granules (Fig. la) and magnetosomes (Fig. lb) were the two well-defined compartments that accumulated significant amounts of minerals.
Running a Multi-Purpose Microscopy Laboratory
Authors: Nockolds C E 
Published: July 2020

Abstract
Multi-purpose microscopy laboratories can be found in a number of different places, including industry, hospitals, government research organizations and universities and the set up and operation of such a laboratory may well be quite different in each of these environments. in this tutorial the issues that are important in the running of a microscopy laboratory will be explored. The main topics include fundamental questions such as whether it is a good idea to have a centralized unit in the first place, how the operation of the laboratory should be funded and what the mix of staff and equipment should be.
Before we talk about how to run a multi-purpose laboratory we should consider the merits of having such a laboratory in a particular institution and whether that unit should be “centralized”. By centralized I mean that it is the preferred option for the institution to have most of the equipment in a central laboratory where it is essentially available to all the interested groups in the organization.
Topics in Electron Diffraction (TEM): A Tutorial
Authors: Eades J A 
Published: July 2020

Abstract
Introduction. Electron diffraction is sometimes considered to be a “difficult subject”. It is certainly one that can not be covered in the space available here. Rather this tutorial will present a few specific aspects of the topic. The topics have been chosen in the hope that they will provide illumination that spreads more widely than just onto the material presented. Several books treat electron diffraction with more generality.
Kikuchi lines Kikuchi lines are of great use in orienting a sample. Unfortunately, in modern microscopes, Kikuchi lines are not seen in selected-area diffraction (SAD). This is because immersion lenses send parallel electrons, from different parts of the sample (like the Kikuchi lines from a flat specimen), to different places in the diffraction pattern. Thus Kikuchi lines are blurred and generally not useful whenever, as in SAD patterns, a large area of the sample contributes to the diffraction pattern.
A History of ESEM in 2.5 Chapters
Authors: Kersker Michael M 
Published: July 2020

Abstract
Microscopy has always been concerned with the observation of samples in their natural states. The earliest instruments, optical microscopes, did not interfere with the samples which were under observation due to the pervasive presence of visible light in the normal evolution of these entities. Man and science persisted in this direction until Ruska in 1933 invented the electron microscope and the real world changed forever (see MSA Rudenberg for an enlightening description of the early days of man's understanding of the electron and the subsequent invention of the electron microscope). The earliest electron beam instruments were single vacuum chamber entities. As single chamber designs, every element in the optical path was under vacuum. These included the electron gun, the lens and coils, recording film, and of course, the specimen itself. The purpose of the vacuum was quite obvious...to eliminate the scattering of the electrons due to the presence of gas.
Analysis of Interesting Materials in the Environmental SEM: You Put What in Your Microscope?
Authors: Mansfield John F 
Published: July 2020

Abstract
The environmental scanning electron microscope (ESEM™) and variable pressure electron microscope (VPSEM) have become accepted tools in the contemporary electron microscopy facility. Their flexibility and their ability to image almost any sample with little, and often no, specimen preparation has proved so attractive that each manufacturer of scanning electron microscopes now markets a low vacuum model.
The University of Michigan Electron Microbeam Analysis Laboratory (EMAL) operates two variable pressure instruments, an ElectroScan E3 ESEM and a Hitachi S3200N VPSEM. The E3 ESEM was acquired in the early 1990s with funding from the Amoco Foundation and it has been used to examine an extremely wide variety of different materials. Since EMAL serves the entire university community, and offers support to neighboring institutions and local industry, the types of materials examined span a wide range. There are users from Materials Science & Engineering, Chemical Engineering, Nuclear Engineering, Electrical Engineering, Physics, Chemistry, Geology, Biology, Biophysics, Pharmacy and Pharmacology.
Charge Contrast Imaging (CCI) in the Environmental Scanning Electron Microscope: Optimizing Operating Parameters for Calcite
Authors: Doehne Eric , Carson David 
Published: July 2020

Abstract
Charge contrast imaging (CCI) is a useful new method for imaging sub-micron features in crystalline materials using the unique gas/ion/electron imaging system of the environmental scanning electron microscope (Griffin, 1997; Doehne, 1998). Crystal growth zoning, microfractures, solution boundaries, and areas of chemical alteration or recrystallization can be imaged in a wide range of materials (Griffin, 2000; Watt, et al. 2000). While not fully understood, charge contrast images reflect differences in the ability of materials to accept, store and discharge deposited electrons from the primary electron beam. These differences are expressed, in turn, as contrasts in secondary electron emission from flat samples (e.g. these contrasts are not related to topography, as is usually the case). Charge contrast appears be related to differences in electronic properties which are often controlled by defect density. CCI is also affected by small-scale physical defects (such as microfractures) which appear to affect the distribution and timing of charge buildup and discharge in the sample (Johansen, et al. 1997).
Techniques and Applications for Imaging Biological Samples in a Low Vacuum Environmental Scanning Electron Microscope
Authors: Gilpin. C J 
Published: July 2020

Abstract
Of all the commercially available scanning electron microscopes which operate at “low vacuum” the ESEM is the most suitable for examining biological samples. in order to maintain samples with liquid water present the specimen chamber must be capable of operating at a pressure of at least 4.6 Torr (611 pascals) of water vapour pressure (the vapour pressure of water at 0°C). Use of lower pressures or a chamber gas other than water vapour will result in evaporation of water from the sample at a rate dependant on the partial pressure difference between the sample and its surrounding environment. Tables of relative humidity as a function of water vapour pressure and temperature are readily available to calculate desired settings for the microscope.
One of the difficulties associated with examining fresh biological material is the need to have the microscope and sample available in the same location at the same time.If sample collection occurs at a site remote from the microscope inevitable necrotic changes will occur before examination can be carried out.
Modifying an FESEM for Low-Vacuum Work
Authors: Ervin M H 
Published: July 2020

Abstract
Environmental SEM has greatly extended the utility of SEM as a result of an ESEM's ability to image volatile and insulating samples. However, many institutions have older high-vacuum SEMs that they cannot afford to replace with an ESEM. For this reason, a simple and inexpensive pressure cell has been developed for performing low-vacuum SEM in a standard microscope. Rather than backfilling the entire analysis chamber with gas, a small volume of higher pressure is confined at the sample surface with the use of a pressure cell that has a small aperture for admitting the primary beam and a gas inlet. Figure 1 is a photograph of such a simple pressure cell.
The aperture for admitting the primary beam needs to be small enough to limit the escaping gas to an amount below what the standard SEM can pump and still maintain high vacuum. On the other hand, the aperture should be as large as possible to provide a useful field of view.