bluuebunny/crossref_metadata_2025_split huggingface dataset:
Present Concepts and Designs for Gun Monochromators
Authors: Kahl F , Voelkl E 
Published: July 2020

Abstract
The attainable information in transmission electron microscopes is limited today primarily by chromatic aberrations, because the new generation of spherical aberration correctors has practically eliminated resolution limits caused by spherical aberration. If it would be possible to develop an electron source with 0.2 eV energy width, the limitations of chromatic aberrations could be minimized, and techniques like Electron Energy Loss Spectroscopy (EELS) could provide much more detail on the type of bonding between atoms. At present, the main approach to reduce the energy width of present day field emission electron sources is to incorporate a beam monochromator in the electron gun. The challenge for such a monochromator is not only to provide a small energy width of 0.2 eV or less, but also to preserve the brightness of the gun as much as possible at a level of current sufficient for high resolution imaging on a routine basis.
Over the last few years, several different designs for monochromators have been proposed. All designs are based on energy dispersive components which separate electrons of different energies spatially and eliminate the ones with high energy deviation by means of a selection slit.
Focused Ion Beam (FIB): More than Just a Fancy Ion Beam Thinner
Authors: Dravid Vinayak P 
Published: July 2020

Abstract
The potential utility of FIB for routine (and novel) applications has come to forefront recently due to advances in ion optics which now allow formation of focused ion probe of better than ∼10-20 nm containing current density exceeding several A/cm2, with a liquid metal source (typically Gallium). The small ion probe size, coupled with shallow sputtering depth - yet high sputtering yield of ions, has opened several opportunities in machining, lithography and ion-assisted deposition.[1-3] These developments, including automation, multi-specimen stages, cross-compatible specimen holders for FIB/TEM/SEM, use of in-situ electron beam (so-called dual beam), coupled with innovations such as the “lift-off” process[4], have provided an invaluable set of tools for microelectronic defect characterization. However, re-deposition (contamination), ion implantation/damage especially for desirable thinner sections (&lt;∼50 nm) remain major concerns for further applications.
While much of the excitement in TEM community for FIB is due to thin foil specimen preparation (especially in microelectronics), we have been exploiting the site-specific micromachining aspect of FIB beyond specimen preparation for TEM, which is the focus of this contribution. Two broad themes will be presented: One exploits the site-specificity of FIB in making thin sections (including lift-off) at and across localized deformation as in indentation response of micro/nanocomposites. The other involves FIB as a fabrication tool for sputtering/drilling arbitrary shapes and sizes down to 20-50 nm, to enhance functional aspects.
Nanoscale Tomographic Imaging using Focused Ion Beam Sputtering, Secondary Electron Imaging and Secondary Ion Mass Spectrometry
Authors: Hull Robert , Dunn Derren , Kubis Alan 
Published: July 2020

Abstract
As the importance of nano-scaled structures in both science and engineering increases, techniques for reconstructing three-dimensional structural, crystallographic and chemical relationships become increasingly important. in this paper we described a technique which uses focused ion beam (FIB) sputtering to expose successive layers of a 3D sample, coupled with secondary electron imaging and secondary ion mass spectrometry of each sputtered surface. Computer interpolation of these different slice images then enables reconstruction of the 3D structure and chemistry of the sample. These techniques are applicable to almost any inorganic material, at a spatial resolution of tens of nanometers, and fields of view up to (tens of μm).
The FIB instrument used in this study is an FEI 200 with a minimum ion probe diameter &lt; 10 nm, an ion current density ∼ 10 A/cm2, a maximum ion current of 11 nA, and a standard Ga+ ion energy of 30 keV. Our instrument is equipped with a continuous dynode electron multiplies (CDEM) for secondary electron imaging and a quadrupole mass spectrometer for secondary ion mass spectroscopy (SIMS) / element specific mapping. Gallium ions of this energy will ablate any material, with sputter yields typically of order ten, corresponding to a material removal rate of order 1 μm3nA−1s−1.
Three Dimensional Characterization of a Specific Site by an FIB Micro-Sampling Technique
Authors: Yaguchi T , Kuroda Y , Ueki Y , Kamino T , Ohnishi T , Umemura K , Asayama K 
Published: July 2020

Abstract
We have developed an FIB micro-sampling technique to prepare both plan view and cross-sectional TEM specimens from a specific site.
The instruments that were used in this study are the Hitachi FB-2000A FIB system equipped a with micromanipulator unit and an HF-2200 cold field emission 200kV analytical TEM equipped with a scanning attachment allowing both STEM and SEM imaging.
Figure 1 shows a procedure to prepare a micro-sample for either plan view or cross-sectional TEM observation of the specific site. First, the micro-sample for plan view TEM observation is trench milled by using an FIB(Figure 1a). Second, a tip of a micromanipulator W-probe is bonded to the micro-sample with the FIB assisted metal deposition. Then, the micro-sample is lifted out and transferred onto a micro-sample carrier(Figure 1b).
Pre-Thinning for FIB TEM Sample Preparation using the Small Angle Cleavage Technique
Authors: Walck Scott D , Colijn Hendrik , Thompson Greg 
Published: July 2020

Abstract
The Small Angle Cleavage Technique (SACT) can produce samples from brittle and cleavable materials very quickly. It is possible for a skilled person to produce about 10 XTEM specimens in an hour. However, there are materials related limitations to the technique. These include 1) the ductile/brittle nature of the substrate, i.e. the fracture mechanics of the materials, 2) the strength of the interfaces between multi-layers, 3) the thickness of any ductile layers, and 4) the strength of the layer materials. in most of the cases where SACT fails, the sample is near electron transparency at the apex of the sample. Where there is a weak interface as in some multi-layer systems, or where the material itself is weak such as when an evaporated Ge layer is used, some of the film near the substrate is sufficiently thin, but there is a jog in the film stack and further back from the apex it is not transparent. If such a SACT sample is viewed from the surface in an SEM, this apparent delaminating of the top layers is evident and usually within 1 μm of the apex.
The purpose of this paper is to show that the geometry of a SACT-prepared sample is well suited for applying FIB milling for further thinning of the sample to electron transparency. in addition, the FIB can be easily applied to SACT specimens that fail to produce usable samples for the reasons cited above. The SACT method allows two main options for mounting the samples that are illustrated in Fig 1.
Characterization of Ga Implantation during Focused Ion-Beam Milling
Authors: Larson D J , Kvitek R J 
Published: July 2020

Abstract
In recent years, the use of the focused-ion beam (FIB) microscope has become widespread in the areas of materials processing and materials characterizaation. Although initial commercialization of FIB instruments was driven by applications in the semiconductor industry, recently the FIB has emerged as a broad characterization tool capable of imaging, material removal and material deposition. This combination makes it a useful instrument for applications ranging from site-specific sample preparation for transmission electron microscopy1 to thin-film head manufacturing. However, since the interaction of a high-energy ion beam (e.g., 30 keV Ga) with a solid inevitably produces implantation damage and the possibility of other effects such as grain growth, dislocation motion or degradation of magnetic properties, it is important to quantify to what extent the material under examination has been modified. Simple TRIM simulations may provide an estimation of the implantation level and depth to which ions will travel into a solid, but these results may not be accurate because FIB milling is not a static situation.
In order to investigate Ga implantation depth, concentration and possible grain growth effects, three circular regions on a 500 nm thick electroplated Ni-80 at.% Fe film were milled using 30 keV Ga ions at three different beam currents, Fig. 1.
The Effect of Implanted Gallium on the Recrystallization of Amorphous Layers formed during FIB Milling of Silicon
Authors: Rubanov S , Munroe PR 
Published: July 2020

Abstract
The focused ion beam (FIB) miller allows preparation of site-specific transmission electron microscopy (TEM) specimens from a wide range of materials in both cross-sectional and planar configurations [1,2]. However, radiation damage during exposure to the high-energy gallium beam may result in the formation of amorphous regions on thin film specimens. The thickness of such damage layers, on both sides of a TEM specimen, is comparable with the thickness required for lattice imaging. For example, the thickness of an amorphous layer in Si after 30 kV Ga+ FIB processing has been reported in the range from 15 [3] to 28 nm [4]. This problem limits the capabilities of FIB sample fabrication.
The aim of this study was to investigate, in detail, the structure, composition and the thickness of the damage layers in Si specimens after milling with a gallium ion beam. Using a FEI xP200 FIB system, with 30 kV Ga+ ions, a row of trenches on a silicon sample was milled under different beam currents ranging from 150 to 6600 pA. The average size of such trenches was 15×10 μm wide and 1 μm deep. The trenches were then removed from the FIB and sputter coated with a thick Au film to preserve the trench surfaces from further damage during subsequent TEM specimen preparation steps. Cross-sectional TEM specimens of the trench walls were then prepared using standard FIB procedures [5]. Observations were made using a Philips CM 200 Field Emission Gun TEM operating at an accelerating voltage of 200 kV.
Computer-Controlled Transmission Electron Microscopy: Automated Tomography
Authors: van der Krift Theo , Ziese Ulrike , Geerts Willie , Koster Bram 
Published: July 2020

Abstract
The integration of computers and transmission electron microscopes (TEM) in combination with the availability of computer networks evolves in various fields of computer-controlled electron microscopy. Three layers can be discriminated: control of electron-optical elements in the column, automation of specific microscope operation procedures and display of user interfaces. The first layer of development concerns the computer-control of the optical elements of the transmission electron microscope (TEM). Most of the TEM manufacturers have transformed their optical instruments into computer-controlled image capturing devices. Nowadays, the required controls for the currents through lenses and coils of the optical column can be accessed by computer software. The second layer of development is aimed toward further automation of instrument operation. For specific microscope applications, dedicated automated microscope-control procedures are carried out. in this paper, we will discuss our ongoing efforts on this second level towards fully automated electron tomography. The third layer of development concerns virtual- or telemicroscopy. Most telemicroscopy applications duplicate the computer-screen (with accessory controls) at the microscope-site to a computer-screen at another site. This approach allows sharing of equipment, monitoring of instruments by supervisors, as well as collaboration between experts at remote locations.
Electron tomography is a three-dimensional (3D) imaging method with transmission electron microscopy (TEM) that provides high-resolution 3D images of structural arrangements. with electron tomography a series of images is acquired of a sample that is tilted over a large angular range (±70°) with small angular tilt increments.
Newly Automated EPMA with Phase Identification System
Authors: Notoya S , Takahashi H , Okumura T , Nielsen CH 
Published: July 2020

Abstract
We have developed a new Electron Probe Microanalyzer (EPMA), JXA-8100/8200, with improved basic capabilities such as X-ray intensities of wavelength dispersive spectrometers (WDS), imaging functions, automated functions and analysis software. Fig. 1 shows the appearance of JXA-8200, WD/ED combined microanalyzer. in this session, we report mainly on the improved imaging functions, automated functions and analysis software.
The JXA-8100/8200 is the first EPMA in the world to feature 1280 x 1024 pixels high resolution live scanning image display. Regarding scanning image, two or four different signal live images, of course including X-ray images, can be displayed simultaneously. Further, image mixing is also possible to display. On the high resolution image, an operator can choose the probe position or the stage position by mouse clicking. The stage position can also be chosen on the optical microscope (OM) live image. Another new “Swing Mouse” function, which is the seamless movement of mouse pointer between the scanning image display and the computer display, has been developed.
Advanced automated functions, such as autofocus, auto astigmatism and auto contrast brightness, are effective to optimize the scanning image.
Appreciating Massive Data Sets from Tiny Specimens
Authors: Mohler William A 
Published: July 2020

Abstract
Continuing improvements on laser scanning microscopy now allow easy acquisition of multi-gigabyte-sized data sets from single living specimens. These multi-dimensional data comprise stacks of serial optical sections (3D) collected repeatedly over time (4D), often recording separate signal channels simultaneously (5D). in our work imaging developmental and cell biological processes in living embryos, we try to take advantage of the full scope of spatial and temporal detail that microscopes can now accumulate. Aside from the obvious difficulties of data management and archival, we still struggle to visually appreciate both the holistic view of the specimen and the smaller dynamic details that we know are captured within these recordings. Ideally, the multi-dimensional microscopist should view and analyze the specimen as the full set of tens of thousands of images. Although strides have been made, visualization software and computer hardware for browsing and analyzing multi-dimensional data are not yet up to the task of giving the microscopist full kinesthetic access to the thriving subject that the microscope hardware and software have captured. Several pieces of software allow the viewer to fluidly browse the original optical sections through space and over time. Moving beyond the constraints of the raw image plane by rendering, re-slicing, digitally dissecting, and animating the time-varying volumes is the task that is currently so demanding that all approaches are only partially satisfactory.
Cytokine Production and Cellular Localization in a Murine Model of Brain Inflammation
Authors: Cavallo J S , Wu Q , Szczepanik AM , Ying X , Ringheim GE 
Published: July 2020

Abstract
Brain inflammation is typically involved in the pathogenesis of acute conditions such as stroke and brain trauma and in chronic neurodegenerative diseases, for instance, Alzheimer’s disease. Accordingly, a well-characterized in vivo model of brain inflammation can be a useful tool to evaluate specific drug effects focused on various inflammation targets in the pharmaceutical drug discovery process. A model of brain inflammation was induced by the injection of β-amyloid peptide (αβ) or the bacterial endotoxin lipopolysaccharide (LPS) into the lateral ventricles of CD-I mice. The time course and dose response kinetics of cytokine and chemokine production were characterized. Levels of the pro-inflammatory cytokines IL-1α, IL-1β, IL-6 and the chemokine MCP-1 were significantly increased with respect to both time and dose in the cortex and hippocampus as determined by ELISA. Immunohistochemical assays were developed to detect IL-1β to determine cellular localization of this cytokine to microglia and astrocytes. Astrocytes were labeled with antibodies to glial fibrillary acidic protein (GFAP) and microglia were labeled with F4/80 antibodies. IL-1β was localized to cell type in frozen sections using double immunofluorescence (IMF) tags and were visualized with traditional fluorescence and confocal imaging.
Confocal Imaging of Scale Development on Butterfly Wings
Authors: Paddock Stephen W 
Published: July 2020

Abstract
Both surfaces of the butterfly wing are covered with thousands of colored scales that are arranged in precise linear arrays. Each scale contributes a single color to the overall pattern, which is usually different on the upper and lower surface of the wing. Moreover, the scales have a characteristic surface substructure that is visible using confocal autofluorescence (fig. 1). The ridges on the surface of all of the scales function to control the flow of air across the wing surface during gliding flight, and they contribute to the interference colors in a subset of the scales.
The fruit fly Drosophila melanogaster is the closest relative of butterflies for which detailed developmental, genetic and confocal imaging protocols have been established. Specimen preparation techniques for butterfly imaginal discs were largely developed from those for Drosophila tissues. The various stages of butterfly wing development have presented new challenges for confocal imaging. For example, butterfly fifth instar wing imaginal discs are much larger and thicker than those of the fruit fly.
Platelet-Derived Growth Factor (PDGF) Stimulates Embryonic Cardiac Growth and Myofibrillogenesis
Authors: Haley Stephen , Price Robert L , Bullard Tara A , Terracio Louis 
Published: July 2020

Abstract
Congenital heart disease is a leading cause of death in children with about 40,000 babies born in America each year with congenital heart disease. Common problems include atrial septal defects, patent ductus arteriosus and ventricular septal defects. However, very little is known about the underlying causes of congenital heart disease or the embryonic origin of cardiac malformation. The goal of our recent research has been to examine the role that specific growth factors and their receptors play in the development of the contractile apparatus of the heart and the experiments reported here further define the role of PDGF-AA and the PDGF alpha-receptor (PDGFR-α) during early heart growth and morphogenesis.
The PDGF ligand and receptor system consists of two well-characterized ligands, PDGF-A and B, and a third recently identified ligand, PDGF-C. The active forms of PDGFA and B exist as either AA or BB homodimers or an AB heterodimer. The PDGFR-α binds all of the dimers with high affinity while the PDGFR-β binds only the PDGF-BB homodimer with high affinity.
The Feasibility of High Resolution, Multiple Labeling using Colloidal Particles of Similar Size but Different Shapes and Elemental Compositions
Authors: Meyer DA , Albrecht RM 
Published: July 2020

Abstract
High resolution, quantitative cell labeling analysis for electron microscopy is typically accomplished using colloidal gold (cAu) particles which have a uniform diameter such that each particle conjugates no more than one ligand with monovalent specificity, such as an Fab antibody fragment. in this way, one particle labels exactly one target molecule. The corresponding particle size which satisfies this requirement, in the case of the Fab fragment, is 3-5nm. Under these constraints, multiple labeling cannot be performed using the standard cAu technology in which particles of various diameters are used such that each size corresponds to a unique label. Particles larger than 5nm may conjugate multiple Fab fragments, and thus a single particle may lable multiple target sites. Conversely, several particles smaller than 3nm may bind to a single Fab fragment so that several particles may label a single target molecule. Recent work in our lab has focused on the development of a labeling system which maintains the advantages of the standard cAu labeling technology, namely the use of electron-dense particles with excellent secondary and backscattered electron emission properties which make them readily detectable by both TEM and SEM, while at the same time offering greater versatility by permitting multiple labeling for high resolution, quantitative analysis. This novel labeling system makes use of colloidal particles which have unique and distinctive shapes, and composed of a variety of different metals including Au, Ag, Pt, Pd, Rh, and Ru. These elements all form stable aqueous colloidal suspensions, and the particles have surface charge properties similar to those of Au, permitting the adsorption of proteins and other ligands to them by the same conjugation techniques used with cAu (fig. 1).
Molecular Bioengineering of Multifuctional Markers for Energy Filtering Transmission Electron Microscopy (EFTEM) Correlative with Positron Emission Tomography (PET) and Magnetic Resonance Imaging (MRI)
Authors: Malecki Marek , Sun Angel , Wohlwend Lynn , Hsu Annie 
Published: July 2020

Abstract
Molecular immunolabeling allows us to recognize location of molecules within complex biomolecular assemblies, cells, and organs. This technology helps us to facilitate correlations of the data available from biochemistry, molecular biology, pathology, and molecular imaging laboratories concerned with the gene expression as well as location and functions of its products. in this sense, molecular imaging serves as an integrative factor for life sciences endeavors (Albrecht et al. 1992, Bazett-Jones et al. 1996, Hainfeld and Powell 2000, Malecki et al. 1998, Robinson et al. 2000, Malecki 2000). Nevertheless, the essential requirement for pursuit of those projects is availability of molecular markers, which are detectable with various imaging instruments (Malecki 1996). Correlations between positron emission tomography (PET) providing metabolic information, magnetic resonance imaging (MRI) delineating precise anatomical location, and energy filtering transmission electron microscopy (EFTEM) expanding insights into the molecular level are particularly powerful. We have designed three main strategies for pursuit of this project: (a) expression of fusion proteins containing amplified metal binding sites (Malecki et al. 1998), (b) expression of recombinant single chain variable fragment (scFv) antibodies containing elemental recipient (Malecki et al. 2000), and (c) covalent coupling of IgG and Fab with organometallic clusters (Malecki 1996). Herewith, we report the results obtained through imaging of organometallic clusters inserted into the recombinant single chain variable fragment (scFv) antibodies.