bluuebunny/crossref_metadata_2025_split huggingface dataset:
X-Ray Microanalysis in the Environmental SEM Using Mapping and Fourier Deconvolution Techniques
Authors: Phillips Matthew R , Griffin Brendan , Drouin Dominque , Nockolds Clive , Remond Guy 
Published: July 2020

Abstract
X-ray microanalysis of any type of specimen in its natural state without the use of conventional SEM specimen preparation techniques has immense potential in a wide range of scientific and industrial applications. This capability would be particularly useful in microanalysis applications where it is highly desirable to preserve the integrity of the specimen, for example in semiconductor failure analysis and forensic investigations. in principle, this X-ray microanalysis goal can be achieved in an environmental or variable pressure scanning electron microscope (VPSEM) because specimen charging and vacuum stability problems are negated by the presence of a gas in the specimen chamber. However, the accuracy and spatial resolution of X-ray microanalysis in the VPSEM is significantly degraded by the chamber gas as it scatters primary beam electrons, generating spurious X-rays far from the analysis point. to date, two different X-ray measurement strategies have been developed to facilitate X-ray microanalysis at high chamber pressure in the VPSEM.
Modifications Needed for Performing High-Resolution Cryosem in a Hitachi S-4700 Fesem Using an Emitech K1250 Cryo-Preparation System
Authors: Chen Ya , Frethem Chris , Erlandsen Stanley L 
Published: July 2020

Abstract
Cryo-techniques have been successfully used in scanning electron microscopy (SEM). They are especially promising for high-resolution SEM to improve specimen preservation and reduce radiation damage [1, 2]. A number of cryo-preparation systems are commercially available for SEM, however, our experience has shown that modifications are needed to perform highresolution imaging (&gt;50,000x).
Emitech K1250 system consists of a sample preparation chamber, control unit, and cryo-stage. Magnetron sputter coating is standard and electron-beam evaporation is optional. A vacuum transfer device facilitates the sample transfer between the preparation chamber and the SEM to prevent contamination. The Emitech cryo-stage replaces the Hitachi S-4700 standard stage and the cryo-stage temperature is monitored and controlled by the Emitech control unit.
The specimen is mounted on a sample holder that mounts to the cryo-stage. Therefore, the distance from the specimen to cryo-stage, the thermal capacity of the sample holder, and the thermal contact between them will affect the actual temperature of the specimen.
Direct Imaging of Sodium Stearate Crystals Dispersed in Waterpropylene Glycol Mixtures by Cryo-Electron Microscopy
Authors: Ma Yue , Liang J , Zheng Y , Erlandsen S L , Scriven L E , Davis H T 
Published: July 2020

Abstract
Cryo-scanning electron microscopy (cryo-SEM) and cryo-transmission electron microscopy (cryo- TEM), in conjunctions with rheological measurements, light and confocal microscopy, x-ray scattering, and solid state NMR, are used to characterize sodium stearate (NaSt) crystals dispersed in waterpropylene glycol (PG) mixtures at macroscopic, microscopic, molecular, and atomic levels. NaSt is a surface-active, structural agent in household and personal cleaning products, including deodorant sticks and soap bars. A better structural characterization of NaSt/PG/water systems has practical importance in personal care and cosmetic industries. NaSt crystals and other soap crystal morphologies have been studied by the TEM/replica technique. However, the replicas were made of the residue after the original sample or its aqueous dilution were dried, and the original structure may have been lost during drying. Cryo-SEM was not used to study NaSt crystals because of its lower resolution and because the crystals are highly susceptible to radiation damage by electron beam.
A STEM-EDX Study of the Sequestration of Heavy Metal in Different Cell Components by Pseudomonas Aeruginosa
Authors: Goldberg JJ , Jensen TE 
Published: July 2020

Abstract
Cells of Pseudomonas aeruginosa were exposed to six different heavy metals, Al, Cd, Cu, Mn, Pb, Zn, exposure was done at the same concentrations of 20 ppm, except for the Cd which was done at 5 ppm. The cells were then analyzed using the STEM mode of a transmission electron microscope in conjunction with a PGT IMIX energy dispersive xray spectrometer. The data was then analyzed using a bulk sample analysis program (ZAF method) in standardless mode (w/w). We analyzed the cell wall the cytoplasm and polyphosphate bodies. Approximately 20 cells were analyzed per treatment and averages of the elements present were calculated. The cells of Pseudomonas aeruginosa were grown in nutrient broth and then embedded in Epon according to Luft's procedure. Quantitative analysis of the three different parts of the cell revealed that in cells exposed to Al, the wall contained on average 0(55%), C(20%) P( 8.0%) K(10%) Cl(2%) S(5.0%),Al(2.0%), the cytoplasm contained on average, 0(53%) C(20%) P(5.0%) Ca(4.0%) K(12%) Cl(4.0%) Al(2.0%).
Biogenic Mineral Formation by Iron Reducing Bacteria
Authors: Dohnalkova Alice C , Gorby Yuri A , McLean Jeff , Fredrickson Jim K , Kennedy David W 
Published: July 2020

Abstract
Dissimilatory iron reducing bacteria have been extensively studied for their ability to reduce ferric iron Fe(III) to ferrous iron Fe(II), as well as several multivalent heavy metals and radionuclides as a mode of energy-yielding respiration. Shewanella putrefaciens strain CN32 was used to investigate the mechanism of biogenic metal reduction in systems simulating conditions of natural anaerobic iron reducing environments in the subsurface contaminated with U and Tc as a possible strategy for bioremediation of soils containing these contaminants. As previously reviewed, U(VI) is soluble in most groundwaters, while U(VI) generally precipitates as the insoluble mineral uraninite. Formation of bioreduced minerals can lead to immobilization of these contaminants in the subsurface, which might be a very useful strategy for in situ bioremediation.
To determine the metal reduction and the formation of biogenic Fe(II), U(IV) and Tc(IV) minerals, experiments with CN32 exposed to well-defined aqueous solutions were conducted. Metal reduction was measured with time, and the resulting solids were analyzed by X-ray diffraction, scanning electron microscopy (SEM) and energydispersive X-ray spectroscopy (EDS).
Seeing the Forest for the Trees: Selective Staining and Contrast Enhancement Methods for Biological Electron Microscopy
Authors: Ellisman M H 
Published: July 2020

Abstract
Electron tomography has proven to be an invaluable tool for studying the 3-dimensional organization of a wide range of structures, from large cellular processes down to individual macromolecular complexes. An important requirement for electron tomography of thick specimens is the need for selective staining to delineate the structure of interest from other cellular constituents. of particular usefulness in this regard is the method of fluorescence photooxidation, whereby the reactive oxygen generated by a fluorescent compound is used to oxidize diaminobenzidine into a reaction product that can then be visualized with the electron microscope. The main advantages of this method are that not only does it allow for excellent correlated light and electron microscopy, but also the relatively small size of the oxidizing agent used allows for excellent 3-D labeling with high resolution.
This method has proven to be a particularly versatile technique.
The Si/SiO2 Interface: Atomic Structures, Composition, Strain and Energetics
Authors: Pennycook S J , Duscher G , Buczko R , Pantelides S T 
Published: July 2020

Abstract
A number of recent studies of grain boundaries and heterophase interfaces have demonstrated the power of combining Z-contrast STEM imaging, EELS and first-principles theoretical modeling to give an essentially complete atomic scale description of structure, bonding and energetics. Impurity sites and valence can be determined experimentally and configurations determined through calculations.
Here we present an investigation of the Si/SiO2 interface. The Z-contrast image in Fig. la, taken with the VG Microscopes HB603U STEM, shows that the atomic structure of Si is maintained up to the last layers visible. The decrease in intensity near the interface could originate from interfacial roughness of around one unit cell (∼0.5 nm), or may represent dechanneling in the slightly buckled columns induced by the oxide. Fig. lb, taken from a sample with ∼1 nm interface roughness, shows a band of bright contrast near the interface. This is not due to impurities or thickness variation since it disappears on increasing the detector angle from 25 mrad to 45 mrad (Fig. lc), and is therefore due to induced strain.
Things That Go “Bump” in the VPSEM - and How We Image with Them
Authors: Griffin Brendan J 
Published: July 2020

Abstract
Variable pressure scanning electron microscopes (VPSEM) differ from conventional SEM by operating at pressures ranging from the ‘high vacuum’ SEM levels of 10-6 torr up to typically around 2 torr. The environmental SEM or ESEM is a commercial variant which employs an unique multistage pressure-limiting aperture (PLA) system to attain specimen chamber operating pressures of up to 50 torr. Early instruments used air or argon as the imaging gas but more commonly today water vapour is used. A wide range of gases have been employed, including potentially explosive hydrogen-methane mixtures. The choice of gas is operator-based and can be varied during the imaging session.
Early VPESM were restricted to backscattered electron imaging (BSE) until the development of the gaseous secondary electron detector in the ESEM. Gaseous secondary electron detectors are now available for all models of VPSEM and together with compatible cathodoluminescence and EDS XRay detectors, the full range of SEM-based imaging options is present.
The principal distinguishing feature of VPSEM is, of course, that samples can be examined uncoated. Gas-electron interaction generates a positive ion supply that can minimise conventional charging artefacts, in a simple imaging model.
FIB/SEM Dual Beam Instrumentation: Slicing, Dicing, Imaging, and More
Authors: Giannuzzi Lucille A 
Published: July 2020

Abstract
In a focused ion beam (FIB) instrument, ions (typically Ga+) obtained from a liquid metal ion source are accelerated down a column at energies up to ∽ 50 keV. The beam of ions is focused by electrostatic and octopole lens systems and the ion dose (and beam diameter) is controlled using real and/or virtual apertures. Beam sizes in FIB instruments on the order of 5-7 nm may be achieved.
The versatility of the FIB instrument enables large regions of material (e.g., 500 μm3) to be removed at high beam currents in just a couple of minutes. Lower beam currents (i.e., beam diameters) are usually used to remove smaller amounts of material within the same time frame (e.g., ∽ 5μm3). The introduction of an organometallic gas in close proximity to the target allows for the deposition of metals, SiO2, and other materials, by an ion beam assisted chemical vapor deposition process.
The Evolution of Accessibility: The San Diego State University Electron Microscope Facility
Authors: Barlow Steven B 
Published: July 2020

Abstract
A microscope facility at teaching institutions needs to be more than an isolated refuge of researchers. Students must be given easier access to the equipment and an increased awareness of the power of these tools for understanding the scientific principles taught in their lecture classes. The San Diego State College of Sciences supports a shared instrumentation Electron Microscope Facility, a suite of seven rooms that occupies 1500 square feet. The laboratory is fully equipped for all aspects of sample preparation for examination by confocal scanning light microscopy, scanning electron microscopy (SEM) or transmission electron microscopy (TEM). Historically, specialists with many years training in equipment operation, sample preparation, and research protocols have had exclusive access to EM facilities. At SDSU, however, every effort is made to encourage inclusivity via familiarity with and hands-on access to equipment in the EM Facility. in all, over 1000 SDSU students and several hundred community members participate each year in opportunities to access the SDSU EM Facility.
Inside Adobe Photoshop and Acrobat
Authors: Kost Julieanne 
Published: July 2020

Abstract
Adobe Photoshop has been the defacto standard for imaging professionals for many years. Most scientists have adopted this program because of the ease of use and the quality of the output. It is obvious to most who use this program that most users only master a limited subset of this programs' capabilities.
This session is an attempt to introduce more of this imaging applications' capabilites from one of Adbobe's Photoshop Evangelists. I will try to show you how to get the most out of Adobe Photoshop by revealing the most productive and efficient digital imaging workflows. I will focus on developing a greater understanding of the current technology within this powerful imaging application program as well as explain the most efficient methods of manipulating, printing, and posting images on the web. I will demonstrate quick and easy ways to crop and resize images as well as make tonal changes and apply custom color tables (Fig. 1).
Single Molecule Force Spectroscopy Maps to Study Receptors Clustering
Authors: Bhatia R , Almqvist N , Banerjee S , Primbs G , Desai N , Lai R 
Published: July 2020

Abstract
An atomic force microscope (AFM) allows molecular resolution imaging of hydrated specimens. However, it is often limited in providing identity of the imaged structures, especially in a complex system such as a cellular membrane. Cell surface macromolecules such as ion channels and receptors serve as the interface between the cytoplasm and the extracellular region and toward which many regulatory signals are directed. Their density, distribution and clustering are key spatial features influencing effective and proper physiological responses. We used a method that uses AFM “force-volume maps” to identify and map regional distribution as well as ligand-, or antibody-induced real-time clustering of receptors on the cell surface. This technique also allows simultaneous imaging of the resultant changes in cellular micromechanical properties, such as elasticity and cytoskeletal reorganization of the cell. As an appropriate physiological sample, we have examined spatial distribution and real-time clustering of VEGFR, the receptor for vascular endothelial growth factor which is an important angiogenic factor in human and animal tissues.
We have used AFM probes conjugated with anti-VEGFR-antibody (anti-Flk-1 antibody) to examine binding (or unbinding) forces between VEGF-R2 (Flk-1) in both in vitro as well as in live endothelial cells. A quantal set of binding and unbinding forces was measured between the antibody conjugated to the AFM tip and purified VEGFRs adsorbed on to a mica surface (Fig 1). The unbinding force varied between 60 and 240 pN and was a multiple of discrete quantized strength of approximately 60 pN (Figure 1B).
Hitachi S-4700 ExB Filter Design and Applications
Authors: Joens Steve 
Published: July 2020

Abstract
Electron beam - specimen interactions and SEM signals have been well understood and documented for many years. These interactions result in a variety of electron signals including the most common, secondary and backscattered electron. Each electron signal produces unique characteristic information about the sample surface, subsurface, and elemental composition. Important information can be gained by controlling and filtering electron signals collected by the electron detector system.
The S-4700 Cold Field Emission SEM incorporates a set of electrodes and plates positioned in the objective lens upper pole piece in close proximity to the upper secondary detector (figure 1). When a positive voltage is applied to the electrode plates, a high yield of secondary and backscattered electrons spiral up the column of the objective lens. The backscattered electrons are filtered with the ExB producing a SE rich signal. The information from this type of signal provides absolute detail from the sample surface, but can be prone to charging with some highly nonconductive samples. Figure 2a shows the effect of charging while observing uncoated Teflon ™. The image becomes distorted with bright intermittent horizontal lines. Surface detail is enhanced due to the high contribution of SEs from the sample surface.
When the electrode voltage is set negative, through the instrument GUI, the low energy secondary electrons are repelled providing a signal rich in backscattered electrons. The information from this type of signal provides compositional information and inherently reduces charging. The uncoated Teflon ™ sample in figure 2b shows all charging affects have been eliminated.
Development of a Field Emission VP-SEM and Some Initial Applications
Authors: Nishimura Masako , Itoh Sukehiro , Joens Steve 
Published: July 2020

Abstract
The use of variable pressure SEMs (VP-SEMs) is increasing in various fields of science and industry, allowing microscopy in a variable pressure environment of 1 ∼ 270 Pa utilizing backscattered electrons for imaging. The VP-SEM allows microscopy of insulated samples without the need for sample preparation. Charging artifacts can be minimized as well. When the VP-SEM is operated with a cooling stage, which allows cooling of samples at −20° and above, vaporization of water from samples is reduced. This permits microscopy of wet samples at close to the natural state for extended periods of time.
Poor S/N ratio and deterioration of resolution, both of which are due to collisions among residual gas molecules and primary/backscattered electrons, have limited the performance of VP-SEMs. For resolving these limitations, we have completed the development of a new field emission VP-SEM which operates with a stable Schottky field emission source, a new environmental secondary electron detector (ESED), and a multi-stage differential pumping system. Fig. 1 shows a sectional view of the column with the differential pumping system. This design allows stable gun vacuum conditions with variable specimen chamber pressure 10 through 3,000 Pa, permitting a pressure difference from the gun by 1011 Pa without problems.
Evactron™ Cleaning of SEM Specimens using an In-Situ RF Plasma on the SEM Chamber
Authors: Vane R , Strossman G 
Published: July 2020

Abstract
The EVACTRON is a new device (US Patent 6,105,589) designed to remove hydrocarbons from SEM specimens and SEM chambers to prevent contamination artifacts. The device uses a lowpowered RF plasma to make oxygen radicals from air. These radicals oxidize hydrocarbons to make CO, H2O, and CO2 that can be removed by the vacuum pump. The use of air as an oxygen source is convenient to the SEM operator but limits the cleaning effectiveness of the system to easily oxidized carbon species. The system does remove high percentages of the usual contamination problems of vacuum pump oil and skin oil hydrocarbons from surfaces in a relatively short time.
The EVACTRON SEM-CLEAN™ system provides a safe method for plasma cleaning inside the SEM. Air as a diluted oxygen gas mixture is chosen as the plasma reactant gas. Air is passed through a low-power RF glow-discharge to create oxygen radicals inside a generator mounted on a specimen chamber port. The generator chamber is subject to the same vacuum as the specimen chamber, and the vacuum pressure and gas flow are controlled by the EVACTRON SEM-CLEAN controller. The radicals are carried out of the plasma into the whole of the specimen chamber by convection. in the chamber they react with all exposed surfaces including the specimen if present. The plasma itself is confined to the generator chamber, which prevents ion and electron bombardment damage to the instrument or specimen.
The ORNL Aberration-Corrected STEM/TEM Project
Authors: Allard L F , Voelkl E , Blom D A , Nolan T A , Kahl F , Pennycook S J , Kersker M 
Published: July 2020

Abstract
Field emission electron microscopes operating at 200kV or 300kV and incorporating aberration correctors for either the incident electron probe or for the primary aberrations of the objective lens (OL) are currently under development for several laboratories in the world. OL-corrected instruments require monochromators for the electron beam, built into the electron gun prior to the accelerating stages, in order to optimize the contrast transfer characteristics of the objective lens to push the instrumental resolution limit to well beyond 0.1nm. This will allow the point resolution limit as controlled by the correction of spherical aberration Cs to potentially extend to the instrumental limit of better than 0.1nm. Figure 1 shows the contrast transfer characteristics of a Cs-corrected 200kV TEM, both without and with a beam monochromator.
Dedicated STEM instruments such as the 300kV VG-603 and lOOkV VG-501 at Oak Ridge National Laboratory, and other VG instruments at Cornell University and IBM Co. are also being adapted (by Nion Co., Kirkland, WA) to incorporate aberration correctors for the incident probe. The aim is to improve the resolution of the VG-603 instrument in dark-field imaging mode, for example, from 0.13nm to 0.05nm. in another ORNL project, the High Temperature Materials Laboratory has contracted JEOL Ltd. to construct a STEM-TEM instrument with a probe corrector designed and built by CEOS GmbH (Heidelberg, Germany).
Quantitative In-Situ Nanoindentation of Thin Films in a Transmission Electron Microscope
Authors: Minorl AM , Stach EA , Morris JW 
Published: July 2020

Abstract
A unique in situ nanoindentation stage has been built and developed at the National Center for Electron Microscopy in Berkeley, CA. By using piezoceramic actuators to finely position a 3-sided, boron-doped diamond indenter, we are able to image in real time the nanoindentation induced deformation of thin films. Recent work has included the force-calibration of the indenter, using silicon cantilevers to establish a relationship between the voltage applied to the piezoactuators, the displacement of the diamond tip, and the force generated.
In this work, we present real time, in situ TEM observations of the plastic deformation of Al thin films grown on top of lithographically-prepared silicon substrates. The in situ nanoindentations require a unique sample geometry (see Figure 1) in which the indenter approaches the specimen normal to the electron beam. in order to meet this requirement, special wedge-shaped silicon samples were designed and microfabricated so that the tip of the wedge is sharp enough to be electron transparent.