Distinction between amorphous and healed planar deformation features in shocked quartz using composite color scanning electron microscope cathodoluminescence (SEM-CL) imaging

NASA Astrophysics Data System (ADS)

Hamers, Maartje F.; Pennock, Gill M.; Herwegh, Marco; Drury, Martyn R.

2016-10-01

Planar deformation features (PDFs) in quartz are one of the most reliable and most widely used forms of evidence for hypervelocity impact. PDFs can be identified in scanning electron microscope cathodoluminescence (SEM-CL) images, but not all PDFs show the same CL behavior: there are nonluminescent and red luminescent PDFs. This study aims to explain the origin of the different CL emissions in PDFs. Focused ion beam (FIB) thin foils were prepared of specific sample locations selected in composite color SEM-CL images and were analyzed in a transmission electron microscope (TEM). The FIB preparation technique allowed a direct, often one-to-one correlation between the CL images and the defect structure observed in TEM. This correlation shows that composite color SEM-CL imaging allows distinction between amorphous PDFs on one hand and healed PDFs and basal Brazil twins on the other: nonluminescent PDFs are amorphous, while healed PDFs and basal Brazil twins are red luminescent, with a dominant emission peak at 650 nm. We suggest that the red luminescence is the result of preferential beam damage along dislocations, fluid inclusions, and twin boundaries. Furthermore, a high-pressure phase (possibly stishovite) in PDFs can be detected in color SEM-CL images by its blue luminescence.

Three-dimensional characterization of pigment dispersion in dried paint films using focused ion beam-scanning electron microscopy.

PubMed

Lin, Jui-Ching; Heeschen, William; Reffner, John; Hook, John

2012-04-01

The combination of integrated focused ion beam-scanning electron microscope (FIB-SEM) serial sectioning and imaging techniques with image analysis provided quantitative characterization of three-dimensional (3D) pigment dispersion in dried paint films. The focused ion beam in a FIB-SEM dual beam system enables great control in slicing paints, and the sectioning process can be synchronized with SEM imaging providing high quality serial cross-section images for 3D reconstruction. Application of Euclidean distance map and ultimate eroded points image analysis methods can provide quantitative characterization of 3D particle distribution. It is concluded that 3D measurement of binder distribution in paints is effective to characterize the order of pigment dispersion in dried paint films.

FIB-SEM tomography of human skin telocytes and their extracellular vesicles

PubMed Central

Cretoiu, Dragos; Gherghiceanu, Mihaela; Hummel, Eric; Zimmermann, Hans; Simionescu, Olga; Popescu, Laurentiu M

2015-01-01

We have shown in 2012 the existence of telocytes (TCs) in human dermis. TCs were described by transmission electron microscopy (TEM) as interstitial cells located in non-epithelial spaces (stroma) of many organs (see www.telocytes.com). TCs have very long prolongations (tens to hundreds micrometers) named Telopodes (Tps). These Tps have a special conformation with dilated portions named podoms (containing mitochondria, endoplasmic reticulum and caveolae) and very thin segments (below resolving power of light microscopy), called podomers. To show the real 3D architecture of TC network, we used the most advanced available electron microscope technology: focused ion beam scanning electron microscopy (FIB-SEM) tomography. Generally, 3D reconstruction of dermal TCs by FIB-SEM tomography revealed the existence of Tps with various conformations: (i) long, flattened irregular veils (ribbon-like segments) with knobs, corresponding to podoms, and (ii) tubular structures (podomers) with uneven calibre because of irregular dilations (knobs) – the podoms. FIB-SEM tomography also showed numerous extracellular vesicles (diameter 438.6 ± 149.1 nm, n = 30) released by a human dermal TC. Our data might be useful for understanding the role(s) of TCs in intercellular signalling and communication, as well as for comprehension of pathologies like scleroderma, multiple sclerosis, psoriasis, etc. PMID:25823591

Three-dimensional multiscale analysis of degradation of nano- and micro-structure in direct methanol fuel cell electrodes after methanol starvation

NASA Astrophysics Data System (ADS)

Netzeband, Christian; Arlt, Tobias; Wippermann, Klaus; Lehnert, Werner; Manke, Ingo

2016-09-01

This study investigates the ageing effects on the microstructure of the anode catalyst layer of direct methanol fuel cells (DMFC) after complete methanol starvation. To this end the samples of two methanol-depleted membrane electrode assemblies (MEA) have been compared with a pristine reference sample. A three-dimensional characterization of the anode catalyst layer (ACL) structure on a nanometer scale has been conducted by focused ion beam (FIB)/scanning electron microscope (SEM) tomography. The FIB/SEM tomography allows for a detailed analysis of statistic parameters of micro-structured materials, such as porosity, tortuosity and pore size distributions. Furthermore, the SEM images displayed a high material contrast between the heavy catalyst metals (Pt/Ru) and the relatively light carbon support, which made it possible to map the catalyst distribution in the acquired FIB/SEM tomographies. Additional synchrotron X-ray tomographies have been conducted in order to obtain an overview of the structural changes of all the components of a section of the MEAs after methanol depletion.

Large volume serial section tomography by Xe Plasma FIB dual beam microscopy.

PubMed

Burnett, T L; Kelley, R; Winiarski, B; Contreras, L; Daly, M; Gholinia, A; Burke, M G; Withers, P J

2016-02-01

Ga(+) Focused Ion Beam-Scanning Electron Microscopes (FIB-SEM) have revolutionised the level of microstructural information that can be recovered in 3D by block face serial section tomography (SST), as well as enabling the site-specific removal of smaller regions for subsequent transmission electron microscope (TEM) examination. However, Ga(+) FIB material removal rates limit the volumes and depths that can be probed to dimensions in the tens of microns range. Emerging Xe(+) Plasma Focused Ion Beam-Scanning Electron Microscope (PFIB-SEM) systems promise faster removal rates. Here we examine the potential of the method for large volume serial section tomography as applied to bainitic steel and WC-Co hard metals. Our studies demonstrate that with careful control of milling parameters precise automated serial sectioning can be achieved with low levels of milling artefacts at removal rates some 60× faster. Volumes that are hundreds of microns in dimension have been collected using fully automated SST routines in feasible timescales (<24h) showing good grain orientation contrast and capturing microstructural features at the tens of nanometres to the tens of microns scale. Accompanying electron back scattered diffraction (EBSD) maps show high indexing rates suggesting low levels of surface damage. Further, under high current Ga(+) FIB milling WC-Co is prone to amorphisation of WC surface layers and phase transformation of the Co phase, neither of which have been observed at PFIB currents as high as 60nA at 30kV. Xe(+) PFIB dual beam microscopes promise to radically extend our capability for 3D tomography, 3D EDX, 3D EBSD as well as correlative tomography. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

Three-dimensional intracellular structure of a whole rice mesophyll cell observed with FIB-SEM.

PubMed

Oi, Takao; Enomoto, Sakiko; Nakao, Tomoyo; Arai, Shigeo; Yamane, Koji; Taniguchi, Mitsutaka

2017-07-01

Ultrathin sections of rice leaf blades observed two-dimensionally using a transmission electron microscope (TEM) show that the chlorenchyma is composed of lobed mesophyll cells, with intricate cell boundaries, and lined with chloroplasts. The lobed cell shape and chloroplast positioning are believed to enhance the area available for the gas exchange surface for photosynthesis in rice leaves. However, a cell image revealing the three-dimensional (3-D) ultrastructure of rice mesophyll cells has not been visualized. In this study, a whole rice mesophyll cell was observed using a focused ion beam scanning electron microscope (FIB-SEM), which provides many serial sections automatically, rapidly and correctly, thereby enabling 3-D cell structure reconstruction. Rice leaf blades were fixed chemically using the method for conventional TEM observation, embedded in resin and subsequently set in the FIB-SEM chamber. Specimen blocks were sectioned transversely using the FIB, and block-face images were captured using the SEM. The sectioning and imaging were repeated overnight for 200-500 slices (each 50 nm thick). The resultant large-volume image stacks ( x = 25 μm, y = 25 μm, z = 10-25 μm) contained one or two whole mesophyll cells. The 3-D models of whole mesophyll cells were reconstructed using image processing software. The reconstructed cell models were discoid shaped with several lobes around the cell periphery. The cell shape increased the surface area, and the ratio of surface area to volume was twice that of a cylinder having the same volume. The chloroplasts occupied half the cell volume and spread as sheets along the cell lobes, covering most of the inner cell surface, with adjacent chloroplasts in close contact with each other. Cellular and sub-cellular ultrastructures of a whole mesophyll cell in a rice leaf blade are demonstrated three-dimensionally using a FIB-SEM. The 3-D models and numerical information support the hypothesis that rice mesophyll cells enhance their CO 2 absorption with increased cell surface and sheet-shaped chloroplasts. © The Author 2017. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com

FIB-SEM tomography of human skin telocytes and their extracellular vesicles.

PubMed

Cretoiu, Dragos; Gherghiceanu, Mihaela; Hummel, Eric; Zimmermann, Hans; Simionescu, Olga; Popescu, Laurentiu M

2015-04-01

We have shown in 2012 the existence of telocytes (TCs) in human dermis. TCs were described by transmission electron microscopy (TEM) as interstitial cells located in non-epithelial spaces (stroma) of many organs (see www.telocytes.com). TCs have very long prolongations (tens to hundreds micrometers) named Telopodes (Tps). These Tps have a special conformation with dilated portions named podoms (containing mitochondria, endoplasmic reticulum and caveolae) and very thin segments (below resolving power of light microscopy), called podomers. To show the real 3D architecture of TC network, we used the most advanced available electron microscope technology: focused ion beam scanning electron microscopy (FIB-SEM) tomography. Generally, 3D reconstruction of dermal TCs by FIB-SEM tomography revealed the existence of Tps with various conformations: (i) long, flattened irregular veils (ribbon-like segments) with knobs, corresponding to podoms, and (ii) tubular structures (podomers) with uneven calibre because of irregular dilations (knobs) - the podoms. FIB-SEM tomography also showed numerous extracellular vesicles (diameter 438.6 ± 149.1 nm, n = 30) released by a human dermal TC. Our data might be useful for understanding the role(s) of TCs in intercellular signalling and communication, as well as for comprehension of pathologies like scleroderma, multiple sclerosis, psoriasis, etc. © 2015 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yashchuk, Valeriy V; Conley, Raymond; Anderson, Erik H.

We discuss the results of SEM and TEM measurements with the BPRML test samples fabricated from a BPRML (WSi2/Si with fundamental layer thickness of 3 nm) with a Dual Beam FIB (focused ion beam)/SEM technique. In particular, we demonstrate that significant information about the metrological reliability of the TEM measurements can be extracted even when the fundamental frequency of the BPRML sample is smaller than the Nyquist frequency of the measurements. The measurements demonstrate a number of problems related to the interpretation of the SEM and TEM data. Note that similar BPRML test samples can be used to characterize x-raymore » microscopes. Corresponding work with x-ray microscopes is in progress.« less

Focused Ion Beam (FIB) combined with SEM (FIB/SEM) and TEM: Advanced tools for nano-analysis in Geosciences

NASA Astrophysics Data System (ADS)

Wirth, R.; Morales, L. G.

2011-12-01

Focused ion beam (FIB) techniques have been successfully applied to the preparation of site-specific electron transparent membranes for transmission electron microscopy (TEM) investigations in Geosciences since several years. For example, systematic TEM studies of nano-inclusions in diamond foils prepared with FIB have improved our knowledge on diamond formation. However, FIB is not exclusively used for sample preparation for TEM application because it has been proved that one and the same TEM foil can also be used for Synchrotron IR, Synchrotron X-Ray fluorescence (XRF), scanning transmission X-Ray microscopy (STXM) and NanoSIMS analysis. In addition, FIB milling turned out to be very useful for sample preparation of Brillouin scattering experiments and has a strong potential for preparation of highly-polished, micrometer-scale samples. However, a real break through in FIB application was achieved combining a Ga-ion source of the FIB with an electron source of a scanning electron microscope (SEM) in one single instrument. The combination of FIB/SEM renders access to the third dimension of the sample possible. A cavity normal to the sample surface is sputtered with Ga-ions and this newly created inner surface is imaged with the electron beam. Alternating slicing and viewing along these cavities allow the acquisition of a sequence of images that allows the observation in 3 dimensions. Recently, this technique has been successfully applied to image the structure of grain or phase boundaries in metamorphic rocks as well as micro- and nanoporosity in shales, but its applicability goes far beyond these few examples. Combining slicing and viewing with X-Ray and electron backscatter diffraction (EBSD) analysis can provide 3D elemental mapping and 3D crystallographic orientation mapping of crystalline materials. Combined FIB/SEM devices also facilitate the preparation of substantially thinner and cleaner TEM foils (approximately 30 nm) because electron beam imaging controls the progress of the sputtering process without sputtering the sample during imaging. Electron induce sputtering is substantially smaller than ion induced sputtering. Finally, the amorphous layers created by Ga-ion sputtering and Ga-ion implantation can be removed from the foil surfaces by subsequent argon ion bombardment under a low angle of incidence and low acceleration voltage thus permitting TEM high-resolution imaging and electron energy-loss spectroscopy (EELS). Additionally, ultra-thin foils have the advantage that they are electron transparent even at 30 keV, the common operational voltage of a SEM. Therefore the electron column of the FIB/SEM system can be used as a TEM at low voltage and images can be made either in bright-field, dark field and through a high-angle annular dark field (HAADF) detector. The HAADF detector provides information about the chemical composition of the specimen with high spatial resolution because it is Z-contrast sensitive.

Reconstructing the microstructure of polyimide-silicalite mixed-matrix membranes and their particle connectivity using FIB-SEM tomography.

PubMed

Diblíková, P; Veselý, M; Sysel, P; Čapek, P

2018-03-01

Properties of a composite material made of a continuous matrix and particles often depend on microscopic details, such as contacts between particles. Focusing on processing raw focused-ion beam scanning electron microscope (FIB-SEM) tomography data, we reconstructed three mixed-matrix membrane samples made of 6FDA-ODA polyimide and silicalite-1 particles. In the first step of image processing, backscattered electron (BSE) and secondary electron (SE) signals were mixed in a ratio that was expected to obtain a segmented 3D image with a realistic volume fraction of silicalite-1. Second, after spatial alignment of the stacked FIB-SEM data, the 3D image was smoothed using adaptive median and anisotropic nonlinear diffusion filters. Third, the image was segmented using the power watershed method coupled with a seeding algorithm based on geodesic reconstruction from the markers. If the resulting volume fraction did not match the target value quantified by chemical analysis of the sample, the BSE and SE signals were mixed in another ratio and the procedure was repeated until the target volume fraction was achieved. Otherwise, the segmented 3D image (replica) was accepted and its microstructure was thoroughly characterized with special attention paid to connectivity of the silicalite phase. In terms of the phase connectivity, Monte Carlo simulations based on the pure-phase permeability values enabled us to calculate the effective permeability tensor, the main diagonal elements of which were compared with the experimental permeability. In line with the hypothesis proposed in our recent paper (Čapek, P. et al. (2014) Comput. Mater. Sci. 89, 142-156), the results confirmed that the existence of particle clusters was a key microstructural feature determining effective permeability. © 2017 The Authors Journal of Microscopy © 2017 Royal Microscopical Society.

Minimal resin embedding of multicellular specimens for targeted FIB-SEM imaging.

PubMed

Schieber, Nicole L; Machado, Pedro; Markert, Sebastian M; Stigloher, Christian; Schwab, Yannick; Steyer, Anna M

2017-01-01

Correlative light and electron microscopy (CLEM) is a powerful tool to perform ultrastructural analysis of targeted tissues or cells. The large field of view of the light microscope (LM) enables quick and efficient surveys of the whole specimen. It is also compatible with live imaging, giving access to functional assays. CLEM protocols take advantage of the features to efficiently retrace the position of targeted sites when switching from one modality to the other. They more often rely on anatomical cues that are visible both by light and electron microscopy. We present here a simple workflow where multicellular specimens are embedded in minimal amounts of resin, exposing their surface topology that can be imaged by scanning electron microscopy (SEM). LM and SEM both benefit from a large field of view that can cover whole model organisms. As a result, targeting specific anatomic locations by focused ion beam-SEM (FIB-SEM) tomography becomes straightforward. We illustrate this application on three different model organisms, used in our laboratory: the zebrafish embryo Danio rerio, the marine worm Platynereis dumerilii, and the dauer larva of the nematode Caenorhabditis elegans. Here we focus on the experimental steps to reduce the amount of resin covering the samples and to image the specimens inside an FIB-SEM. We expect this approach to have widespread applications for volume electron microscopy on multiple model organisms. Copyright © 2017 Elsevier Inc. All rights reserved.

Correlative tomography at the cathode/electrolyte interfaces of solid oxide fuel cells

NASA Astrophysics Data System (ADS)

Wankmüller, Florian; Szász, Julian; Joos, Jochen; Wilde, Virginia; Störmer, Heike; Gerthsen, Dagmar; Ivers-Tiffée, Ellen

2017-08-01

This paper introduces a correlative tomography technique. It visualizes the spatial organization of primary and secondary phases at the interface of La0.58Sr0.4Co0.2Fe0.8O3-δ cathode/10 mol% Gadolinia doped Ceria/8 mol% Yttria stabilized Zirconia electrolyte. It uses focused ion beam/scanning electron microscope tomography (FIB/SEM), and combines data sets from Everhart-Thornley and Inlens detector differentiating four primary and two secondary material phases. In addition, grayscale information is correlated to elemental distribution gained by energy dispersive X-ray spectroscopy in a scanning transmission electron microscope. Interdiffusion of GDC into YSZ and SrZrO3 as secondary phases depend (in both amount and spatial organization) on the varied co-sintering temperature of the GDC/YSZ electrolyte. The ion-blocking SrZrO3 forms a continuous layer on top of the temperature-dependent GDC/YSZ interdiffusion zone (ID) at and below a co-sintering temperature of 1200 °C; above it becomes intermittent. 2D FIB/SEM images of primary and secondary phases at 1100, 1200, 1300 and 1400 °C were combined with a 3D FIB/SEM reconstruction (1300 °C). This reveals that ;preferred; oxygen ion transport pathways from the LSCF cathode through GDC and the ID into the YSZ electrolyte only exist in samples sintered above 1200 °C. The applied correlative technique expands our understanding of this multiphase cathode/electrolyte interface region.

FIB/SEM technology and Alzheimer's disease: three-dimensional analysis of human cortical synapses.

PubMed

Blazquez-Llorca, Lidia; Merchán-Pérez, Ángel; Rodríguez, José-Rodrigo; Gascón, Jorge; DeFelipe, Javier

2013-01-01

The quantification and measurement of synapses is a major goal in the study of brain organization in both health and disease. Serial section electron microscopy (EM) is the ideal method since it permits the direct quantification of crucial features such as the number of synapses per unit volume or the distribution and size of synapses. However, a major limitation is that obtaining long series of ultrathin sections is extremely time-consuming and difficult. Consequently, quantitative EM studies are scarce and the most common method employed to estimate synaptic density in the human brain is indirect, by counting at the light microscopic level immunoreactive puncta using synaptic markers. The recent development of automatic EM methods in experimental animals, such as the combination of focused ion beam milling and scanning electron microscopy (FIB/SEM), are opening new avenues. Here we explored the utility of FIB/SEM to examine the cerebral cortex of Alzheimer's disease patients. We found that FIB/SEM is an excellent tool to study in detail the ultrastructure and alterations of the synaptic organization of the human brain. Using this technology, it is possible to reconstruct different types of plaques and the surrounding neuropil to find new aspects of the pathological process associated with the disease, namely; to count the exact number and types of synapses in different regions of the plaques, to study the spatial distribution of synapses, and to analyze the morphology and nature of the various types of dystrophic neurites and amyloid deposits.

Cross-sectional TEM specimen preparation for W/B{sub 4}C multilayer sample using FIB

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mondal, Puspen, E-mail: puspen@rrcat.gov.in; Pradhan, P. C.; Tiwari, Pragya

2016-05-23

A recent emergence of a cross-beam scanning electron microscopy (SEM)/focused-ion-beam (FIB) system have given choice to fabricate cross-sectional transmission electron microscopy (TEM) specimen of thin film multilayer sample. A 300 layer pair thin film multilayer sample of W/B{sub 4}C was used to demonstrate the specimen lift-out technique in very short time as compared to conventional cross-sectional sample preparation technique. To get large area electron transparent sample, sample prepared by FIB is followed by Ar{sup +} ion polishing at 2 kV with grazing incident. The prepared cross-sectional sample was characterized by transmission electron microscope.

Microscale localization and isolation of light emitting imperfections in monocrystalline silicon solar cells

NASA Astrophysics Data System (ADS)

Gajdoš, Adam; Škvarenina, Lubomír.; Škarvada, Pavel; Macků, Robert

2017-12-01

An imperfections or defects may appear in fabricated monocrystalline solar cells. These microstructural imperfections could have impact on the parameters of whole solar cell. The research is divided into two parts, firstly, the detection and localization defects by using several techniques including current-voltage measurement, scanning probe microscopy (SPM), scanning electron microscope (SEM) and electroluminescence. Secondly, the defects isolation by a focused ion beam (FIB) milling and impact of a milling process on solar cells. The defect detection is realized by I-V measurement under reverse biased sample. For purpose of localization, advantage of the fact that defects or imperfections in silicon solar cells emit the visible and near infrared electroluminescence under reverse biased voltage is taken, and CCD camera measurement for macroscopic localization of these spots is applied. After rough macroscopic localization, microscopic localization by scanning probe microscopy combined with a photomultiplier (shadow mapping) is performed. Defect isolation is performed by a SEM equipped with the FIB instrument. FIB uses a beam of gallium ions which modifies crystal structure of a material and may affect parameters of solar cell. As a result, it is interesting that current in reverse biased sample with isolated defect is smaller approximately by 2 orders than current before isolation process.

Line-width roughness of advanced semiconductor features by using FIB and planar-TEM as reference metrology

NASA Astrophysics Data System (ADS)

Takamasu, Kiyoshi; Takahashi, Satoru; Kawada, Hiroki; Ikota, Masami

2018-03-01

LER (Line Edge Roughness) and LWR (Line Width Roughness) of the semiconductor device are an important evaluation scale of the performance of the device. Conventionally, LER and LWR is evaluated from CD-SEM (Critical Dimension Scanning Electron Microscope) images. However, CD-SEM measurement has a problem that high frequency random noise is large, and resolution is not sufficiently high. For random noise of CD-SEM measurement, some techniques are proposed. In these methods, it is necessary to set parameters for model and processing, and it is necessary to verify the correctness of these parameters using reference metrology. We have already proposed a novel reference metrology using FIB (Focused Ion Beam) process and planar-TEM (Transmission Electron Microscope) method. In this study, we applied the proposed method to three new samples such as SAQP (Self-Aligned Quadruple Patterning) FinFET device, EUV (Extreme Ultraviolet Lithography) conventional resist, and EUV new material resist. LWR and PSD (Power Spectral Density) of LWR are calculated from the edge positions on planar-TEM images. We confirmed that LWR and PSD of LWR can be measured with high accuracy and evaluated the difference by the proposed method. Furthermore, from comparisons with PSD of the same sample by CD-SEM, the validity of measurement of PSD and LWR by CD-SEM can be verified.

The Interior Analysis and 3-D Reconstruction of Internally-Mixed Light-Absorbing Atmospheric Particles

NASA Astrophysics Data System (ADS)

Conny, J. M.; Collins, S. M.; Anderson, I.; Herzing, A.

2010-12-01

Carbon-containing atmospheric particles may either absorb solar or outgoing long-wave radiation or scatter solar radiation, and thus, affect Earth’s radiative balance in multiple ways. Light-absorbing carbon that is common in urban air particles such as industrial coke dust, road dust, and diesel soot, often exists in the same particle with other phases that contain, for example, aluminum, calcium, iron, and sulfur. While the optical properties of atmospheric particles in general depend on overall particle size and shape, the inhomogeneity of chemical phases within internally-mixed particles may also greatly affect particle optical properties. In this study, a series of microscopic approaches were used to identify individual light-absorbing coarse-mode particles and to assess their interior structure and composition. Particle samples were collected in 2004 from one of the U.S. EPA’s Los Angeles Particulate Matter Supersites, and were likely affected substantially by road dust and construction dust. First, bright-field and dark-field light microscopy and computer-controlled scanning electron microscopy (SEM) with energy-dispersive x-ray spectroscopy (EDX) were used to distinguish predominantly light-absorbing carbonaceous particles from other particle types such as mineral dust, sea salt, and brake wear. Second, high-resolution SEM-EDX elemental mapping of individual carbonaceous particles was used to select particles with additional elemental phases that exhibited spatial inhomogeneity. Third, focused ion-beam SEM (FIB-SEM) with EDX was used to slice through selected particles to expose interior surfaces and to determine the spatial distribution of element phases throughout the particles. Fourth, study of the interior phases of a particle was augmented by the transmission electron microscopy (TEM) of a thin section of the particle prepared by FIB-SEM. Here, electron energy loss spectroscopy with TEM was used to study chemical bonding in the carbonaceous phase. Finally, automated serial slicing and imaging in the FIB-SEM generated a stack of secondary electron images of the particles’ interior surfaces that allowed for the 3-D reconstruction of the particles, a process known as FIB tomography. Interior surface of light-absorbing carbonaceous particle from FIB-SEM analysis.

Simulation of FIB-SEM images for analysis of porous microstructures.

PubMed

Prill, Torben; Schladitz, Katja

2013-01-01

Focused ion beam nanotomography-scanning electron microscopy tomography yields high-quality three-dimensional images of materials microstructures at the nanometer scale combining serial sectioning using a focused ion beam with SEM. However, FIB-SEM tomography of highly porous media leads to shine-through artifacts preventing automatic segmentation of the solid component. We simulate the SEM process in order to generate synthetic FIB-SEM image data for developing and validating segmentation methods. Monte-Carlo techniques yield accurate results, but are too slow for the simulation of FIB-SEM tomography requiring hundreds of SEM images for one dataset alone. Nevertheless, a quasi-analytic description of the specimen and various acceleration techniques, including a track compression algorithm and an acceleration for the simulation of secondary electrons, cut down the computing time by orders of magnitude, allowing for the first time to simulate FIB-SEM tomography. © Wiley Periodicals, Inc.

Focussed Ion Beam Milling and Scanning Electron Microscopy of Brain Tissue

PubMed Central

Knott, Graham; Rosset, Stéphanie; Cantoni, Marco

2011-01-01

This protocol describes how biological samples, like brain tissue, can be imaged in three dimensions using the focussed ion beam/scanning electron microscope (FIB/SEM). The samples are fixed with aldehydes, heavy metal stained using osmium tetroxide and uranyl acetate. They are then dehydrated with alcohol and infiltrated with resin, which is then hardened. Using a light microscope and ultramicrotome with glass knives, a small block containing the region interest close to the surface is made. The block is then placed inside the FIB/SEM, and the ion beam used to roughly mill a vertical face along one side of the block, close to this region. Using backscattered electrons to image the underlying structures, a smaller face is then milled with a finer ion beam and the surface scrutinised more closely to determine the exact area of the face to be imaged and milled. The parameters of the microscope are then set so that the face is repeatedly milled and imaged so that serial images are collected through a volume of the block. The image stack will typically contain isotropic voxels with dimenions as small a 4 nm in each direction. This image quality in any imaging plane enables the user to analyse cell ultrastructure at any viewing angle within the image stack. PMID:21775953

Multi-scale characterization by FIB-SEM/TEM/3DAP.

PubMed

Ohkubo, T; Sepehri-Amin, H; Sasaki, T T; Hono, K

2014-11-01

In order to improve properties of functional materials, it is important to understand the relation between the structure and the properties since the structure has large effect to the properties. This can be done by using multi-scale microstructure analysis from macro-scale to nano and atomic scale. Scanning electron microscope (SEM) equipped with focused ion beam (FIB), transmission electron microscope (TEM) and 3D atom probe (3DAP) are complementary analysis tools making it possible to know the structure and the chemistry from micron to atomic resolution. SEM gives us overall microstructural and chemical information by various kinds of detectors such as secondary electron, backscattered electron, EDS and EBSD detectors. Also, it is possible to analyze 3D structure and chemistry via FIB serial sectioning. In addition, using TEM we can focus on desired region to get more complementary information from HRTEM/STEM/Lorentz images, SAED/NBD patterns and EDS/EELS to see the detail micro or nano-structure and chemistry. Especially, combination of probe Cs corrector and split EDS detectors with large detector size enable us to analyze the atomic scale elemental distribution. Furthermore, if the specimen has a complicated 3D nanostructure, or we need to analyze light elements such as hydrogen, lithium or boron, 3DAP can be used as the only technique which can visualize and analyze distribution of all constituent atoms of our materials within a few hundreds nm area. Hence, site-specific sample preparation using FIB/SEM is necessary to get desired information from region of interest. Therefore, this complementary analysis combination works very well to understand the detail of materials.In this presentation, we will show the analysis results obtained from some of functional materials by Carl Zeiss CrossBeam 1540EsB FIB/SEM, FEI Tecnai G(2) F30, Titan G2 80-200 TEMs and locally build laser assisted 3DAP. As the one of the example, result of multi-scale characterization for ultra-fine grain Nd-Fe-B permanent magnet will be shown [1]. In order to improve the magnetic properties, especially to increase the coercivity (resistance against magnetization reversal) of the magnet, decreasing the grain size and isolating each grain by non-ferromagnetic grain boundary phase are quite important since the nucleation of magnetic reversal from grain boundary phase can be suppressed and pinning force of magnetic domain wall at the grain boundary phase can be strengthened. Therefore, micro and nano structure and chemistry analysis can shed a light do grain boundary engineering.Figure 1(a,b) shows SEM BSE images of ultrafine grain Nd-Fe-B sintered magnet and the reconstructed 3D tomography of Nd-rich phases obtained by FIB/SEM serial sectioning. This data can provide us information about the distribution of Nd-rich phase and its volume fraction. Moreover, the HRTEM image from the grain boundary phase, the 3DAP maps and the concentration depth profiles are shown in Fig. 1(c,d,e). This magnet shows high coercivity (1517kA/m), and by comparing these results with the microstructures of low coercivity specimen, importance of grain boundary formation was confirmed and it gives us hint to improve the coercivity further. We will show the detail and results from other materials.jmicro;63/suppl_1/i6/DFU046F1F1DFU046F1Fig. 1.(a) SEM BSE images of ultrafine grain Nd-Fe-B sintered magnet. (b) 3D FIB/SEM tomography of Nd-rich phases. (c) HRTEM image from the grain boundary phase. (d) 3DAP maps of Nd, Cu and Al. (e) Concentration depth profiles for Fe, Nd+Pr, B, Co, Cu and Al, determined from the selected box in (d)[1]. © The Author 2014. Published by Oxford University Press on behalf of The Japanese Society of Microscopy. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Two novel approaches to study arthropod anatomy by using dualbeam FIB/SEM.

PubMed

Di Giulio, Andrea; Muzzi, Maurizio

2018-03-01

Transmission Electron Microscopy (TEM) has always been the conventional method to study arthropod ultrastructure, while the use of Scanning Electron Microscopy (SEM) was mainly devoted to the examination of the external cuticular structures by secondary electrons. The new generation field emission SEMs are capable to generate images at sub-cellular level, comparable to TEM images employing backscattered electrons. The potential of this kind of acquisition becomes very powerful in the dual beam FIB/SEM where the SEM column is combined with a Focused Ion Beam (FIB) column. FIB uses ions as a nano-scalpel to slice samples fixed and embedded in resin, replacing traditional ultramicrotomy. We here present two novel methods, which optimize the use of FIB/SEM for studying arthropod anatomy. Copyright © 2017 Elsevier Ltd. All rights reserved.

In-plane and through-plane non-uniform carbon corrosion of polymer electrolyte fuel cell cathode catalyst layer during extended potential cycles

NASA Astrophysics Data System (ADS)

Ghosh, Sourov; Ohashi, Hidenori; Tabata, Hiroshi; Hashimasa, Yoshiyuki; Yamaguchi, Takeo

2017-09-01

The impact of electrochemical carbon corrosion via potential cycling durability tests mimicking start-stop operation events on the microstructure of the cathode catalyst layer in polymer electrolyte fuel cells (PEFCs) is investigated using focused ion beam (FIB) fabrication without/with the pore-filling technique and subsequent scanning electron microscope (SEM) observations. FIB/SEM investigations without pore-filling reveals that the durability test induces non-uniform cathode shrinking across the in-plane direction; the thickness of the catalyst layer decreases more under the gas flow channel compared to the area under the rim of the flow field. Furthermore, FIB/SEM investigations with the pore-filling technique reveal that the durability test also induces non-uniform cathode shrinking in the through-plane direction; the pores in the area close to the membrane are more shrunken compared with those close to the microporous layer. In particular, a thin area (1-1.5 μm) close to the membrane is found to be severely damaged; it includes closed pores that hinder mass transport through the catalyst layer. It is suggested that uneven carbon corrosion and catalyst layer compaction are responsible for the performance loss during potential cycling operation of PEFCs.

Through-silicon via plating void metrology using focused ion beam mill

NASA Astrophysics Data System (ADS)

Rudack, A. C.; Nadeau, J.; Routh, R.; Young, R. J.

2012-03-01

3D IC integration continues to increase in complexity, employing advanced interconnect technologies such as throughsilicon vias (TSVs), wafer-to-wafer (W2W) bonding, and multi-chip stacking. As always, the challenge with developing new processes is to get fast, effective feedback to the integration engineer. Ideally this data is provided by nondestructive in-line metrology, but this is not always possible. For example, some form of physical cross-sectioning is still the most practical way to detect and characterize TSV copper plating voids. This can be achieved by cleaving, followed by scanning electron microscope (SEM) inspection. A more effective physical cross-sectioning method has been developed using an automated dual-beam focused ion beam (FIB)-SEM system, in which multiple locations can be sectioned and imaged while leaving the wafer intact. This method has been used routinely to assess copper plating voids over the last 24 months at SEMATECH. FIB-SEM feedback has been used to evaluate new plating chemistries, plating recipes, and process tool requalification after downtime. The dualbeam FIB-SEM used for these studies employs a gallium-based liquid metal ion source (LMIS). The overall throughput of relatively large volumes being milled is limited to 3-4 hours per section due to the maximum available beam current of 20 nA. Despite the larger volumetric removal rates of other techniques (e.g., mechanical polishing, broad-ion milling, and laser ablation), the value of localized, site-specific, and artifact-free FIB milling is well appreciated. The challenge, therefore, has been to reap the desired FIB benefits, but at faster volume removal rates. This has led to several system and technology developments for improving the throughput of the FIB technique, the most recent being the introduction of FIBs based on an inductively coupled plasma (ICP) ion source. The ICP source offers much better performance than the LMIS at very high beam currents, enabling more than 1 μA of ion beam current for fast material removal. At a lower current, the LMIS outperforms the ICP source, but imaging resolution below 30 nm has been demonstrated with ICP-based systems. In addition, the ICP source allows a wide range of possible ion species, with Xe currently the milling species of choice, due to its high mass and favorable ion source performance parameters. Using a 1 μA Xe beam will have an overall milling rate for silicon some 20X higher than a Ga beam operating at 65 nA. This paper will compare the benefits already seen using the Ga-based FIB-SEM approach to TSV metrology, with the improvements in throughput and time-to-data obtained by using the faster material removal capabilities of a FIB based on an ICP ion source. Plasma FIB (PFIB) is demonstrated to be a feasible tool for TSV plating void metrology.

Microscopic observations of osteoblast growth on micro-arc oxidized β titanium

NASA Astrophysics Data System (ADS)

Chen, Hsien-Te; Chung, Chi-Jen; Yang, Tsai-Ching; Tang, Chin-Hsin; He, Ju-Liang

2013-02-01

Titanium alloys are widely used in orthopedic and dental implants, owing to their excellent physical properties and biocompatibility. By using the micro-arc oxidation (MAO), we generated anatase-rich (A-TiO2) and rutile-rich (R-TiO2) titanium dioxide coatings, individually on β-Ti alloy, in which the latter achieved an enhanced in vitro and in vivo performance. Thoroughly elucidating how the osteoblasts interact with TiO2 coatings is of worthwhile interest. This study adopts the focused ion beam (FIB) to section off the TiO2 coated samples for further scanning electron microscope (SEM) and transmission electron microscope (TEM) observation. The detailed crystal structures of the TiO2 coated specimens are also characterized. Experimental results indicate osteoblasts adhered more tenaciously and grew conformably with more lamellipodia extent on the R-TiO2 specimen than on the A-TiO2 and raw β-Ti specimens. FIB/SEM cross-sectional images of the cell/TiO2 interface revealed micro gaps between the cell membrane and contact surface of A-TiO2 specimen, while it was not found on the R-TiO2 specimen. Additionally, the number of adhered and proliferated cells on the R-TiO2 specimen was visually greater than the others. Closely examining EDS line scans and elemental mappings of the FIB/TEM cross-sectional images of the cell/TiO2 interface reveals both the cell body and interior space of the TiO2 coating contain nitrogen and sulfur (the biological elements in cell). This finding supports the assumption that osteoblast can grow into the porous structure of TiO2 coatings and demonstrating that the R-TiO2 coating formed by MAO serves the best for β-Ti alloys as orthopedic and dental implants.

Correlation of two-photon in vivo imaging and FIB/SEM microscopy

PubMed Central

Blazquez-Llorca, L; Hummel, E; Zimmerman, H; Zou, C; Burgold, S; Rietdorf, J; Herms, J

2015-01-01

Advances in the understanding of brain functions are closely linked to the technical developments in microscopy. In this study, we describe a correlative microscopy technique that offers a possibility of combining two-photon in vivo imaging with focus ion beam/scanning electron microscope (FIB/SEM) techniques. Long-term two-photon in vivo imaging allows the visualization of functional interactions within the brain of a living organism over the time, and therefore, is emerging as a new tool for studying the dynamics of neurodegenerative diseases, such as Alzheimer’s disease. However, light microscopy has important limitations in revealing alterations occurring at the synaptic level and when this is required, electron microscopy is mandatory. FIB/SEM microscopy is a novel tool for three-dimensional high-resolution reconstructions, since it acquires automated serial images at ultrastructural level. Using FIB/SEM imaging, we observed, at 10 nm isotropic resolution, the same dendrites that were imaged in vivo over 9 days. Thus, we analyzed their ultrastructure and monitored the dynamics of the neuropil around them. We found that stable spines (present during the 9 days of imaging) formed typical asymmetric contacts with axons, whereas transient spines (present only during one day of imaging) did not form a synaptic contact. Our data suggest that the morphological classification that was assigned to a dendritic spine according to the in vivo images did not fit with its ultrastructural morphology. The correlative technique described herein is likely to open opportunities for unravelling the earlier unrecognized complexity of the nervous system. Lay Description Neuroscience and the understanding of brain functions are closely linked to the technical advances in microscopy. In this study we performed a correlative microscopy technique that offers the possibility to combine 2 photon in vivo imaging and FIB/SEM microscopy. Long term 2 photon in vivo imaging allows the visualization of functional interactions within the brain of a living organism over the time, and therefore, is emerging as a new tool to study the dynamics of neurodegenerative diseases, such as Alzheimer’s disease. However, light microscopy has important limitations in revealing synapses that are the connections between neurons, and for this purpose, the electron microscopy is necessary. FIB/SEM microscopy is a novel tool for three-dimensional (3D) high resolution reconstructions since it acquires automated serial images at ultrastructural level. This correlative technique will open up new horizons and opportunities for unravelling the complexity of the nervous system. PMID:25786682

Three-dimensional microstructural characterization of bulk plutonium and uranium metals using focused ion beam technique

NASA Astrophysics Data System (ADS)

Chung, Brandon W.; Erler, Robert G.; Teslich, Nick E.

2016-05-01

Nuclear forensics requires accurate quantification of discriminating microstructural characteristics of the bulk nuclear material to identify its process history and provenance. Conventional metallographic preparation techniques for bulk plutonium (Pu) and uranium (U) metals are limited to providing information in two-dimension (2D) and do not allow for obtaining depth profile of the material. In this contribution, use of dual-beam focused ion-beam/scanning electron microscopy (FIB-SEM) to investigate the internal microstructure of bulk Pu and U metals is demonstrated. Our results demonstrate that the dual-beam methodology optimally elucidate microstructural features without preparation artifacts, and the three-dimensional (3D) characterization of inner microstructures can reveal salient microstructural features that cannot be observed from conventional metallographic techniques. Examples are shown to demonstrate the benefit of FIB-SEM in improving microstructural characterization of microscopic inclusions, particularly with respect to nuclear forensics.

Three-dimensional microstructural characterization of bulk plutonium and uranium metals using focused ion beam technique

DOE PAGES

Chung, Brandon W.; Erler, Robert G.; Teslich, Nick E.

2016-03-03

Nuclear forensics requires accurate quantification of discriminating microstructural characteristics of the bulk nuclear material to identify its process history and provenance. Conventional metallographic preparation techniques for bulk plutonium (Pu) and uranium (U) metals are limited to providing information in two-dimension (2D) and do not allow for obtaining depth profile of the material. In this contribution, use of dual-beam focused ion-beam/scanning electron microscopy (FIB-SEM) to investigate the internal microstructure of bulk Pu and U metals is demonstrated. Our results demonstrate that the dual-beam methodology optimally elucidate microstructural features without preparation artifacts, and the three-dimensional (3D) characterization of inner microstructures can revealmore » salient microstructural features that cannot be observed from conventional metallographic techniques. As a result, examples are shown to demonstrate the benefit of FIB-SEM in improving microstructural characterization of microscopic inclusions, particularly with respect to nuclear forensics.« less

A novel approach to TEM preparation with a (7-axis stage) triple-beam FIB-SEM system

NASA Astrophysics Data System (ADS)

Clarke, Jamil J.

2015-10-01

Preparation of lamellae from bulk to grid for Cs-corrected Transmission Electron Microscope (TEM) observation has mostly become routine work on the latest FIB-SEM systems, with standardized techniques that often are left to automation for the initial steps. The finalization of lamellae however, has mostly become, non-routine, non-repeatable and often driven by user experience level in most cases to produce high quality damage-less cross section. Materials processing of the latest technologies, with ever-shrinking Nano-sized structures pose challenges to modern FIB-SEM systems. This can often lead to specialized techniques and hyper-specific functions for producing ultra-thin high quality lamellae that often are lab specific, preventing practical use of such techniques across multiple materials and applications. Several factors that should be incorporated in processing fine structured materials successfully include how the use of electron and ion scan conditions can affect a thin section during ion milling, the type of ion species applied for material processing during the finalization of lamellae with gallium ions or of a smaller ion species type such as Ar/Xe, sample orientation of the lamella during the thinning process which is linked to ion beam incident angle as a direct relationship in the creation of waterfall effects or curtain effects, and how software can be employed to aid in the reduction of these artifacts with reproducible results regardless of FIB-SEM experience for site-specific lift outs. A traditional TEM preparation was performed of a fine structure specimen in pursuit of a process technique to produce a high quality TEM lamella which would address all of the factors mentioned. These new capabilities have been refined and improved upon during the FIB-SEM design and development stages with an end result of a new approach that yields an improvement in quality by the reduction of common ion milling artifacts such as curtain effects, amorphous material, and better pin pointing of the area of interest while reducing overall processing time for the TEM sample preparation process and enhancing repeatability through ease of use via software controls. The development of these new technologies, incorporating a third Ar/Xe ion beam column in conjunction with the electron and gallium ion beam column, a 7-axis stage for enhanced sample orientation with tilt functions in two axes and automated swing control along with a host of additional functions which address the factors aforementioned such as electron and ion scan techniques and curtain effect removal by the use of hardware and software components that are key to reduce typical FIB related artifacts, all of which are called "ACE [Anti Curtaining Effect] Technologies" are explained. The overall developments of these technologies are to address a significant point that productivity, throughput and repeatability are comprised by synergy between the user, application, software and hardware within a FIB-SEM system. The latest Hitachi FIB-SEM platform offers these innovations for reliability, repeatability and high quality lamella preparation for Cs-corrected (S)TEMs.

Multi-signal FIB/SEM tomography

NASA Astrophysics Data System (ADS)

Giannuzzi, Lucille A.

2012-06-01

Focused ion beam (FIB) milling coupled with scanning electron microscopy (SEM) on the same platform enables 3D microstructural analysis of structures using FIB for serial sectioning and SEM for imaging. Since FIB milling is a destructive technique, the acquisition of multiple signals from each slice is desirable. The feasibility of collecting both an inlens backscattered electron (BSE) signal and an inlens secondary electron (SE) simultaneously from a single scan of the electron beam from each FIB slice is demonstrated. The simultaneous acquisition of two different SE signals from two different detectors (inlens vs. Everhart-Thornley (ET) detector) is also possible. Obtaining multiple signals from each FIB slice with one scan increases the acquisition throughput. In addition, optimization of microstructural and morphological information from the target is achieved using multi-signals. Examples of multi-signal FIB/SEM tomography from a dental implant will be provided where both material contrast from the bone/ceramic coating/Ti substrate phases and porosity in the ceramic coating will be characterized.

In situ micro-compression testing of He2+ ion irradiated titanium aluminide

NASA Astrophysics Data System (ADS)

Wei, Tao; Xu, Alan; Zhu, Hanliang; Ionescu, Mihail; Bhattacharyya, Dhriti

2017-10-01

A titanium aluminide (TiAl) alloy 45XD has been irradiated by a He ion beam with an energy of 5 MeV on a tandem accelerator at the Australian Nuclear Science and Technology Organization (ANSTO). The total fluence of He ions was 5 × 1017 ion cm-2. A 17 μm uniform damage region from the material surface with a helium concentration of about 5000 appm was achieved by using an energy degrading wheel in front of the TiAl target. The micro-size test specimens from the damage layer were fabricated using a focused ion beam & scanning electron microscope (FIB-SEM) system. The in situ SEM micromechanical compressive testing was carried out inside an SEM and the results indicated irradiation embrittlement in the helium affected region. Electron back scatter diffraction (EBSD) analysis has been applied to reveal the orientation of the lamellae in the TiAl specimens, and used to understand the deformation processes in the sample. The irradiation damage of gallium ion beam from FIB on the surface of TiAl sample was also investigated.

Making the practically impossible "Merely difficult"--Cryogenic FIB lift-out for "Damage free" soft matter imaging.

PubMed

Parmenter, Christopher D J; Fay, Michael W; Hartfield, Cheryl; Eltaher, Hoda M

2016-04-01

The preparation of thinned lamellae from bulk samples for transmission electron microscopy (TEM) analysis has been possible in the focussed ion beam scanning electron microscope (FIB-SEM) for over 20 years via the in situ lift-out method. Lift-out offers a fast and site specific preparation method for TEM analysis, typically in the field of materials science. More recently it has been applied to a low-water content biological sample (Rubino 2012). This work presents the successful lift-out of high-water content lamellae, under cryogenic conditions (cryo-FIB lift-out) and using a nanomanipulator retaining its full range of motion, which are advances on the work previously done by Rubino (2012). Strategies are explored for maintaining cryogenic conditions, grid attachment using cryo-condensation of water and protection of the lamella when transferring to the TEM. © 2016 Wiley Periodicals, Inc.

New advances in scanning microscopy and its application to study parasitic protozoa.

PubMed

de Souza, Wanderley; Attias, Marcia

2018-07-01

Scanning electron microscopy has been used to observe and study parasitic protozoa for at least 40 years. However, field emission electron sources, as well as improvements in lenses and detectors, brought the resolution power of scanning electron microscopes (SEM) to a new level. Parallel to the refinement of instruments, protocols for preservation of the ultrastructure, immunolabeling, exposure of cytoskeleton and inner structures of parasites and host cells were developed. This review is focused on protozoan parasites of medical and veterinary relevance, e.g., Toxoplasma gondii, Tritrichomonas foetus, Giardia intestinalis, and Trypanosoma cruzi, compilating the main achievements in describing the fine ultrastructure of their surface, cytoskeleton and interaction with host cells. Two new resources, namely, Helium Ion Microscopy (HIM) and Slice and View, using either Focused Ion Beam (FIB) abrasion or Microtome Serial Sectioning (MSS) within the microscope chamber, combined to backscattered electron imaging of fixed (chemically or by quick freezing followed by freeze substitution and resin embedded samples is bringing an exponential amount of valuable information. In HIM there is no need of conductive coating and the depth of field is much higher than in any field emission SEM. As for FIB- and MSS-SEM, high resolution 3-D models of areas and volumes larger than any other technique allows can be obtained. The main results achieved with all these technological tools and some protocols for sample preparation are included in this review. In addition, we included some results obtained with environmental/low vacuum scanning microscopy and cryo-scanning electron microscopy, both promising, but not yet largely employed SEM modalities. Copyright © 2018. Published by Elsevier Inc.

Human cardiac telocytes: 3D imaging by FIB-SEM tomography

PubMed Central

Cretoiu, D; Hummel, E; Zimmermann, H; Gherghiceanu, M; Popescu, L M

2014-01-01

Telocyte (TC) is a newly identified type of cell in the cardiac interstitium (www.telocytes.com). TCs are described by classical transmission electron microscopy as cells with very thin and long telopodes (Tps; cellular prolongations) having podoms (dilations) and podomers (very thin segments). TCs’ three-dimensional (3D) morphology is still unknown. Cardiac TCs seem to be particularly involved in long and short distance intercellular signalling and, therefore, their 3D architecture is important for understanding their spatial connections. Using focused ion beam scanning electron microscopy (FIB-SEM) we show, for the first time, the whole ultrastructural anatomy of cardiac TCs. 3D reconstruction of cardiac TCs by FIB-SEM tomography confirms that they have long, narrow but flattened (ribbon-like) telopodes, with humps generated by the podoms. FIB-SEM tomography also confirms the network made by TCs in the cardiac interstitium through adherens junctions. This study provides the first FIB-SEM tomography of a human cell type. PMID:25327290

Super-resolution for asymmetric resolution of FIB-SEM 3D imaging using AI with deep learning.

PubMed

Hagita, Katsumi; Higuchi, Takeshi; Jinnai, Hiroshi

2018-04-12

Scanning electron microscopy equipped with a focused ion beam (FIB-SEM) is a promising three-dimensional (3D) imaging technique for nano- and meso-scale morphologies. In FIB-SEM, the specimen surface is stripped by an ion beam and imaged by an SEM installed orthogonally to the FIB. The lateral resolution is governed by the SEM, while the depth resolution, i.e., the FIB milling direction, is determined by the thickness of the stripped thin layer. In most cases, the lateral resolution is superior to the depth resolution; hence, asymmetric resolution is generated in the 3D image. Here, we propose a new approach based on an image-processing or deep-learning-based method for super-resolution of 3D images with such asymmetric resolution, so as to restore the depth resolution to achieve symmetric resolution. The deep-learning-based method learns from high-resolution sub-images obtained via SEM and recovers low-resolution sub-images parallel to the FIB milling direction. The 3D morphologies of polymeric nano-composites are used as test images, which are subjected to the deep-learning-based method as well as conventional methods. We find that the former yields superior restoration, particularly as the asymmetric resolution is increased. Our super-resolution approach for images having asymmetric resolution enables observation time reduction.

Three-dimensional ultrastructure of osteocytes assessed by focused ion beam-scanning electron microscopy (FIB-SEM).

PubMed

Hasegawa, Tomoka; Yamamoto, Tomomaya; Hongo, Hiromi; Qiu, Zixuan; Abe, Miki; Kanesaki, Takuma; Tanaka, Kawori; Endo, Takashi; de Freitas, Paulo Henrique Luiz; Li, Minqi; Amizuka, Norio

2018-04-01

The aim of this study is to demonstrate the application of focused ion beam-scanning electron microscopy, FIB-SEM for revealing the three-dimensional features of osteocytic cytoplasmic processes in metaphyseal (immature) and diaphyseal (mature) trabeculae. Tibiae of eight-week-old male mice were fixed with aldehyde solution, and treated with block staining prior to FIB-SEM observation. While two-dimensional backscattered SEM images showed osteocytes' cytoplasmic processes in a fragmented fashion, three-dimensional reconstructions of FIB-SEM images demonstrated that osteocytes in primary metaphyseal trabeculae extended their cytoplasmic processes randomly, thus maintaining contact with neighboring osteocytes and osteoblasts. In contrast, diaphyseal osteocytes extended thin cytoplasmic processes from their cell bodies, which ran perpendicular to the bone surface. In addition, these osteocytes featured thick processes that branched into thinner, transverse cytoplasmic processes; at some point, however, these transverse processes bend at a right angle to run perpendicular to the bone surface. Osteoblasts also possessed thicker cytoplasmic processes that branched off as thinner processes, which then connected with cytoplasmic processes of neighboring osteocytes. Thus, FIB-SEM is a useful technology for visualizing the three-dimensional structures of osteocytes and their cytoplasmic processes.

Beam deceleration for block-face scanning electron microscopy of embedded biological tissue.

PubMed

Ohta, Keisuke; Sadayama, Shoji; Togo, Akinobu; Higashi, Ryuhei; Tanoue, Ryuichiro; Nakamura, Kei-ichiro

2012-04-01

The beam deceleration (BD) method for scanning electron microscopes (SEM) also referred to as "retarding" was applied to back-scattered electron (BSE) imaging of the flat block face of a resin embedded biological specimen under low accelerating voltage and low beam current conditions. BSE imaging was performed with 0-4 kV of BD on en bloc stained rat hepatocyte. BD drastically enhanced the compositional contrast of the specimen and also improved the resolution at low landing energy levels (1.5-3 keV) and a low beam current (10 pA). These effects also functioned in long working distance observation, however, stage tilting caused uncorrectable astigmatism in BD observation. Stage tilting is mechanically required for a FIB/SEM, so we designed a novel specimen holder to minimize the unfavorable tilting effect. The FIB/SEM 3D reconstruction using the new holder showed a reasonable contrast and resolution high enough to analyze individual cell organelles and also the mitochondrial cristae structures (~5 nm) of the hepatocyte. These results indicate the advantages of BD for block face imaging of biological materials such as cells and tissues under low-voltage and low beam current conditions. Copyright © 2011 Elsevier Ltd. All rights reserved.

Human cardiac telocytes: 3D imaging by FIB-SEM tomography.

PubMed

Cretoiu, D; Hummel, E; Zimmermann, H; Gherghiceanu, M; Popescu, L M

2014-11-01

Telocyte (TC) is a newly identified type of cell in the cardiac interstitium (www.telocytes.com). TCs are described by classical transmission electron microscopy as cells with very thin and long telopodes (Tps; cellular prolongations) having podoms (dilations) and podomers (very thin segments). TCs' three-dimensional (3D) morphology is still unknown. Cardiac TCs seem to be particularly involved in long and short distance intercellular signalling and, therefore, their 3D architecture is important for understanding their spatial connections. Using focused ion beam scanning electron microscopy (FIB-SEM) we show, for the first time, the whole ultrastructural anatomy of cardiac TCs. 3D reconstruction of cardiac TCs by FIB-SEM tomography confirms that they have long, narrow but flattened (ribbon-like) telopodes, with humps generated by the podoms. FIB-SEM tomography also confirms the network made by TCs in the cardiac interstitium through adherens junctions. This study provides the first FIB-SEM tomography of a human cell type. © 2014 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.

FIB-SEM imaging of carbon nanotubes in mouse lung tissue.

PubMed

Købler, Carsten; Saber, Anne Thoustrup; Jacobsen, Nicklas Raun; Wallin, Håkan; Vogel, Ulla; Qvortrup, Klaus; Mølhave, Kristian

2014-06-01

Ultrastructural characterisation is important for understanding carbon nanotube (CNT) toxicity and how the CNTs interact with cells and tissues. The standard method for this involves using transmission electron microscopy (TEM). However, in particular, the sample preparation, using a microtome to cut thin sample sections for TEM, can be challenging for investigation of regions with agglomerations of large and stiff CNTs because the CNTs cut with difficulty. As a consequence, the sectioning diamond knife may be damaged and the uncut CNTs are left protruding from the embedded block surface excluding them from TEM analysis. To provide an alternative to ultramicrotomy and subsequent TEM imaging, we studied focused ion beam scanning electron microscopy (FIB-SEM) of CNTs in the lungs of mice, and we evaluated the applicability of the method compared to TEM. FIB-SEM can provide serial section volume imaging not easily obtained with TEM, but it is time-consuming to locate CNTs in the tissue. We demonstrate that protruding CNTs after ultramicrotomy can be used to locate the region of interest, and we present FIB-SEM images of CNTs in lung tissue. FIB-SEM imaging was applied to lung tissue from mice which had been intratracheally instilled with two different multiwalled CNTs; one being short and thin, and the other longer and thicker. FIB-SEM was found to be most suitable for detection of the large CNTs (Ø ca. 70 nm), and to be well suited for studying CNT agglomerates in biological samples which is challenging using standard TEM techniques.

Enhanced FIB-SEM systems for large-volume 3D imaging.

PubMed

Xu, C Shan; Hayworth, Kenneth J; Lu, Zhiyuan; Grob, Patricia; Hassan, Ahmed M; García-Cerdán, José G; Niyogi, Krishna K; Nogales, Eva; Weinberg, Richard J; Hess, Harald F

2017-05-13

Focused Ion Beam Scanning Electron Microscopy (FIB-SEM) can automatically generate 3D images with superior z-axis resolution, yielding data that needs minimal image registration and related post-processing. Obstacles blocking wider adoption of FIB-SEM include slow imaging speed and lack of long-term system stability, which caps the maximum possible acquisition volume. Here, we present techniques that accelerate image acquisition while greatly improving FIB-SEM reliability, allowing the system to operate for months and generating continuously imaged volumes > 10 6 µm 3 . These volumes are large enough for connectomics, where the excellent z resolution can help in tracing of small neuronal processes and accelerate the tedious and time-consuming human proofreading effort. Even higher resolution can be achieved on smaller volumes. We present example data sets from mammalian neural tissue, Drosophila brain, and Chlamydomonas reinhardtii to illustrate the power of this novel high-resolution technique to address questions in both connectomics and cell biology.

Counting Synapses Using FIB/SEM Microscopy: A True Revolution for Ultrastructural Volume Reconstruction.

PubMed

Merchán-Pérez, Angel; Rodriguez, José-Rodrigo; Alonso-Nanclares, Lidia; Schertel, Andreas; Defelipe, Javier

2009-01-01

The advent of transmission electron microscopy (TEM) in the 1950s represented a fundamental step in the study of neuronal circuits. The application of this technique soon led to the realization that the number of synapses changes during the course of normal life, as well as under certain pathological or experimental circumstances. Since then, one of the main goals in neurosciences has been to define simple and accurate methods to estimate the magnitude of these changes. Contrary to analysing single sections, TEM reconstructions are extremely time-consuming and difficult. Therefore, most quantitative studies use stereological methods to define the three-dimensional characteristics of synaptic junctions that are studied in two dimensions. Here, to count the exact number of synapses per unit of volume we have applied a new three-dimensional reconstruction method that involves the combination of focused ion beam milling and scanning electron microscopy (FIB/SEM). We show that the images obtained with FIB/SEM are similar to those obtained with TEM, but with the advantage that FIB/SEM permits serial reconstructions of large volumes of tissue to be generated rapidly and automatically. Furthermore, we compared the estimates of the number of synapses obtained with stereological methods with the values obtained by FIB/SEM reconstructions. We concluded that FIB/SEM not only provides the actual number of synapses per volume but it is also much easier and faster to use than other currently available TEM methods. More importantly, it also avoids most of the errors introduced by stereological methods and overcomes the difficulties associated with these techniques.

Advantages and Disadvantages of using a Focused Ion Beam to Prepare TEM Samples From Irradiated U-10Mo Monolithic Nuclear Fuel

DOE Office of Scientific and Technical Information (OSTI.GOV)

B. D. Miller; J. Gan; J. Madden

2012-05-01

Transmission electron microscopy (TEM), scanning electron microscopy (SEM), and focused ion beam (FIB) milling were performed on an irradiated U-10Mo monolithic fuel to understand its irradiation microstructure. This is the first reported TEM work of irradiated fuel sample prepared using a FIB. Advantages and disadvantages of using the FIB to create TEM samples from this irradiated fuel will be presented along with some results from the work. Sample preparation techniques used to create SEM and FIB samples from the brittle irradiated monolithic sample will also be discussed.

Recent improvement of a FIB-SEM serial-sectioning method for precise 3D image reconstruction - application of the orthogonally-arranged FIB-SEM.

PubMed

Hara, Toru

2014-11-01

IntroductionWe installed the first "orthogonally-arranged" FIB-SEM in 2011. The most characteristic point of this instrument is that the FIB and SEM columns are perpendicularly mounted; this is specially designed to obtain a serial-sectioning dataset more accurately and precisely with higher contrast and higher spatial resolution compare to other current FIB-SEMs [1]. Since the installation in 2011, we have developed the hardware and methodology of the serial-sectioning based on this orthogonal FIB-SEM. In order to develop this technique, we have widely opened this instrument to every researcher of all fields. In the presentation, I would like to introduce some of application results that are obtained by users of this instrument. The characteristic points of the orthogonal systemFigure 1 shows a difference between the standard and the orthogonal FIB-SEM systems: In the standard system, shown in Fig.1(a), optical axes of a FIB and a SEM crosses around 60deg., while in the orthogonal system (Fig.1(b)), they are perpendicular to each other. The standard arrangement (a) is certainly suitable for TEM lamellae preparation etc. because the FIB and the SEM can see the same position simultaneously. However, for a serial-sectioning, it is not to say the best arrangement. One of the reasons is that the sliced plane by the FIB is not perpendicular to the electron beam so that the background contrast is not uniform and observed plane is distorted. On the other hand, in case of the orthogonally-arranged system,(b), these problems are resolved. In addition, spatial resolution can keep high enough even in a low accelerating voltage (e.g. 500V) because a working distance is set very small, 2mm. From these special design, we can obtain the serial-sectioning dataset from rather wide area (∼100um) with high spatial resolution (Max. 2×2×2nm). As this system has many kinds of detectors: SE, ET, Backscatter Electron(Energy-selective), EDS, EBSD, STEM(BF&ADF), with Ar+ ion-gun and a plasma cleaner, many kinds of signals can be obtained simultaneously.jmicro;63/suppl_1/i5-a/DFU077F1F1DFU077F1Fig. 1.Schematic illustration described (a) a standard type arrangement, (b) an orthogonal type arrangement. Recent topics and Future prospectsWe have applied this instrument for wide area of microstructure analysis; Metals and Alloys, Semiconductor devices, Battery electrodes, Minerals, Biomaterials, and so on. In my presentation, I would like to introduce some of our application results and will discuss about future development of the methodology of a FIB-SEM serial sectioning. As the applied research field becomes wider, various requests for the method were arisen. However, most requests can be summarized as follows: observation of larger area, expansion of applicable sample, obtain many kind of information, linkage with other instruments. AcknowledgmentsThe instrument introduced in this work was installed at NIMS by a part of "Low-carbon research network Japan" funded by the MEXT,Japan. © The Author 2014. Published by Oxford University Press on behalf of The Japanese Society of Microscopy. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Quantification of silver nanoparticle uptake and distribution within individual human macrophages by FIB/SEM slice and view.

PubMed

Guehrs, Erik; Schneider, Michael; Günther, Christian M; Hessing, Piet; Heitz, Karen; Wittke, Doreen; López-Serrano Oliver, Ana; Jakubowski, Norbert; Plendl, Johanna; Eisebitt, Stefan; Haase, Andrea

2017-03-21

Quantification of nanoparticle (NP) uptake in cells or tissues is very important for safety assessment. Often, electron microscopy based approaches are used for this purpose, which allow imaging at very high resolution. However, precise quantification of NP numbers in cells and tissues remains challenging. The aim of this study was to present a novel approach, that combines precise quantification of NPs in individual cells together with high resolution imaging of their intracellular distribution based on focused ion beam/ scanning electron microscopy (FIB/SEM) slice and view approaches. We quantified cellular uptake of 75 nm diameter citrate stabilized silver NPs (Ag 75 Cit) into an individual human macrophage derived from monocytic THP-1 cells using a FIB/SEM slice and view approach. Cells were treated with 10 μg/ml for 24 h. We investigated a single cell and found in total 3138 ± 722 silver NPs inside this cell. Most of the silver NPs were located in large agglomerates, only a few were found in clusters of fewer than five NPs. Furthermore, we cross-checked our results by using inductively coupled plasma mass spectrometry and could confirm the FIB/SEM results. Our approach based on FIB/SEM slice and view is currently the only one that allows the quantification of the absolute dose of silver NPs in individual cells and at the same time to assess their intracellular distribution at high resolution. We therefore propose to use FIB/SEM slice and view to systematically analyse the cellular uptake of various NPs as a function of size, concentration and incubation time.

Implementation of focused ion beam (FIB) system in characterization of nuclear fuels and materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

A. Aitkaliyeva; J. W. Madden; B. D. Miller

2014-10-01

Beginning in 2007, a program was established at the Idaho National Laboratory to update key capabilities enabling microstructural and micro-chemical characterization of highly irradiated and/or radiologically contaminated nuclear fuels and materials at scales that previously had not been achieved for these types of materials. Such materials typically cannot be contact handled and pose unique hazards to instrument operators, facilities, and associated personnel. One of the first instruments to be acquired was a Dual Beam focused ion beam (FIB)-scanning electron microscope (SEM) to support preparation of transmission electron microscopy and atom probe tomography samples. Over the ensuing years, techniques have beenmore » developed and operational experience gained that has enabled significant advancement in the ability to characterize a variety of fuel types including metallic, ceramic, and coated particle fuels, obtaining insights into in-reactor degradation phenomena not obtainable by any other means. The following article describes insights gained, challenges encountered, and provides examples of unique results obtained in adapting Dual Beam FIB technology to nuclear fuels characterization.« less

Enhanced FIB-SEM systems for large-volume 3D imaging

PubMed Central

Xu, C Shan; Hayworth, Kenneth J; Lu, Zhiyuan; Grob, Patricia; Hassan, Ahmed M; García-Cerdán, José G; Niyogi, Krishna K; Nogales, Eva; Weinberg, Richard J; Hess, Harald F

2017-01-01

Focused Ion Beam Scanning Electron Microscopy (FIB-SEM) can automatically generate 3D images with superior z-axis resolution, yielding data that needs minimal image registration and related post-processing. Obstacles blocking wider adoption of FIB-SEM include slow imaging speed and lack of long-term system stability, which caps the maximum possible acquisition volume. Here, we present techniques that accelerate image acquisition while greatly improving FIB-SEM reliability, allowing the system to operate for months and generating continuously imaged volumes > 106 µm3. These volumes are large enough for connectomics, where the excellent z resolution can help in tracing of small neuronal processes and accelerate the tedious and time-consuming human proofreading effort. Even higher resolution can be achieved on smaller volumes. We present example data sets from mammalian neural tissue, Drosophila brain, and Chlamydomonas reinhardtii to illustrate the power of this novel high-resolution technique to address questions in both connectomics and cell biology. DOI: http://dx.doi.org/10.7554/eLife.25916.001 PMID:28500755

Enhanced FIB-SEM systems for large-volume 3D imaging

DOE PAGES

Xu, C. Shan; Hayworth, Kenneth J.; Lu, Zhiyuan; ...

2017-05-13

Focused Ion Beam Scanning Electron Microscopy (FIB-SEM) can automatically generate 3D images with superior z-axis resolution, yielding data that needs minimal image registration and related post-processing. Obstacles blocking wider adoption of FIB-SEM include slow imaging speed and lack of long-term system stability, which caps the maximum possible acquisition volume. Here, we present techniques that accelerate image acquisition while greatly improving FIB-SEM reliability, allowing the system to operate for months and generating continuously imaged volumes > 10 6 ?m 3 . These volumes are large enough for connectomics, where the excellent z resolution can help in tracing of small neuronal processesmore » and accelerate the tedious and time-consuming human proofreading effort. Even higher resolution can be achieved on smaller volumes. We present example data sets from mammalian neural tissue, Drosophila brain, and Chlamydomonas reinhardtii to illustrate the power of this novel high-resolution technique to address questions in both connectomics and cell biology.« less

Three dimensional rock microstructures: insights from FIB-SEM tomography

NASA Astrophysics Data System (ADS)

Drury, Martyn; Pennock, Gill; de Winter, Matthijs

2016-04-01

Most studies of rock microstructures investigate two-dimensional sections or thin slices of three dimensional grain structures. With advances of X-ray and electron tomography methods the 3-D microstructure can be(relatively) routinely investigated on scales from a few microns to cm. 3D studies are needed to investigate the connectivity of microstructures and to test the assumptions we use to calculate 3D properties from 2D sections. We have used FIB-SEM tomography to study the topology of melts in synthetic olivine rocks, 3D crystal growth microstructures, pore networks and subgrain structures. The technique uses a focused ion beam to make serial sections with a spacing of tens to hundreds of nanometers. Each section is then imaged or mapped using the electron beam. The 3D geometry of grains and subgrains can be investigated using orientation contrast or EBSD mapping. FIB-SEM tomography of rocks and minerals can be limited by charging of the uncoated surfaces exposed by the ion beam. The newest generation of FIB-SEMs have much improved low voltage imaging capability allowing high resolution charge free imaging. Low kV FIB-SEM tomography is now widely used to study the connectivity of pore networks. In-situ fluids can also be studied using cryo-FIB-SEM on frozen samples, although special freezing techniques are needed to avoid artifacts produced by ice crystallization. FIB-SEM tomography is complementary, in terms of spatial resolution and sampled volume, to TEM tomography and X-ray tomography, and the combination of these methods can cover a wide range of scales. Our studies on melt topology in synthetic olivine rocks with a high melt content show that many grain boundaries are wetted by nanometre scale melt layers that are too thin to resolve by X-ray tomography. A variety of melt layer geometries occur consistent with several mechanisms of melt layer formation. The nature of melt geometries along triple line junctions and quadruple points can be resolved. Quadruple point junctions between four grains cannot be investigated in 2D studies. 3D microstructural studies suggest that triple lines and quadruple points are important sites for the initiation of recrystallization, reaction and fracture.

Spin-coated epoxy resin embedding technique enables facile SEM/FIB thickness determination of porous metal oxide ultra-thin films.

PubMed

Peña, B; Owen, G Rh; Dettelbach, K E; Berlinguette, C P

2018-01-25

A facile nonsubjective method was designed to measure porous nonconductive iron oxide film thickness using a combination of a focused ion beam (FIB) and scanning electron microscopy. Iron oxide films are inherently nonconductive and porous, therefore the objective of this investigation was to optimize a methodology that would increase the conductivity of the film to facilitate high resolution imaging with a scanning electron microscopy and to preserve the porous nature of the film that could potentially be damaged by the energy of the FIB. Sputter coating the sample with a thin layer of iridium before creating the cross section with the FIB decreased sample charging and drifting, but differentiating the iron layer from the iridium coating with backscattered electron imaging was not definitive, making accurate assumptions of the delineation between the two metals difficult. Moreover, the porous nature of the film was lost due to beam damage following the FIB process. A thin layer plastication technique was therefore used to embed the porous film in epoxy resin that would provide support for the film during the FIB process. However, the thickness of the resin created using conventional thin layer plastication processing varied across the sample, making the measuring process only possible in areas where the resin layer was at its thinnest. Such variation required navigating the area for ideal milling areas, which increased the subjectivity of the process. We present a method to create uniform thin resin layers, of controlled thickness, that are ideal for quantifying the thickness of porous nonconductive films with FIB/scanning electron microscopy. © 2018 The Authors Journal of Microscopy © 2018 Royal Microscopical Society.

FIB/SEM and SEM/EDS microstructural analysis of metal-ceramic and zirconia-ceramic interfaces.

PubMed

Massimi, F; Merlati, G; Sebastiani, M; Battaini, P; Menghini, P; Bemporad, E

2012-01-10

Recently introduced FIB/SEM analysis in microscopy seems to provide a high-resolution characterization of the samples by 3D (FIB) cross-sectioning and (SEM) high resolution imaging. The aim of this study was to apply the FIB/SEM and SEM/EDS analysis to the interfaces of a metal-ceramic vs. two zirconia-ceramic systems. Plate samples of three different prosthetic systems were prepared in the dental lab following the manufacturers' instructions, where metal-ceramic was the result of a ceramic veneering (porcelain-fused-to-metal) and the two zirconia-ceramic systems were produced by the dedicated CAD-CAM procedures of the zirconia cores (both with final sintering) and then veneered by layered or heat pressed ceramics. In a FIB/SEM equipment (also called DualBeam), a thin layer of platinum (1 μm) was deposited on samples surface crossing the interfaces, in order to protect them during milling. Then, increasingly deeper trenches were milled by a focused ion beam, first using a relatively higher and later using a lower ion current (from 9 nA to 0.28 nA, 30KV). Finally, FEG-SEM (5KV) micrographs (1000-50,000X) were acquired. In a SEM the analysis of the morphology and internal microstructure was performed by 13KV secondary and backscattered electrons signals (in all the samples). The compositional maps were then performed by EDS probe only in the metal-ceramic system (20kV). Despite the presence of many voids in all the ceramic layers, it was possible to identify: (1) the grain structures of the metallic and zirconia substrates, (2) the thin oxide layer at the metal-ceramic interface and its interactions with the first ceramic layer (wash technique), (3) the roughness of the two different zirconia cores and their interactions with the ceramic interface, where the presence of zirconia grains in the ceramic layer was reported in two system possibly due to sandblasting before ceramic firing.

Multimodal Hierarchical Imaging of Serial Sections for Finding Specific Cellular Targets within Large Volumes

PubMed Central

Wacker, Irene U.; Veith, Lisa; Spomer, Waldemar; Hofmann, Andreas; Thaler, Marlene; Hillmer, Stefan; Gengenbach, Ulrich; Schröder, Rasmus R.

2018-01-01

Targeting specific cells at ultrastructural resolution within a mixed cell population or a tissue can be achieved by hierarchical imaging using a combination of light and electron microscopy. Samples embedded in resin are sectioned into arrays consisting of ribbons of hundreds of ultrathin sections and deposited on pieces of silicon wafer or conductively coated coverslips. Arrays are imaged at low resolution using a digital consumer like smartphone camera or light microscope (LM) for a rapid large area overview, or a wide field fluorescence microscope (fluorescence light microscopy (FLM)) after labeling with fluorophores. After post-staining with heavy metals, arrays are imaged in a scanning electron microscope (SEM). Selection of targets is possible from 3D reconstructions generated by FLM or from 3D reconstructions made from the SEM image stacks at intermediate resolution if no fluorescent markers are available. For ultrastructural analysis, selected targets are finally recorded in the SEM at high-resolution (a few nanometer image pixels). A ribbon-handling tool that can be retrofitted to any ultramicrotome is demonstrated. It helps with array production and substrate removal from the sectioning knife boat. A software platform that allows automated imaging of arrays in the SEM is discussed. Compared to other methods generating large volume EM data, such as serial block-face SEM (SBF-SEM) or focused ion beam SEM (FIB-SEM), this approach has two major advantages: (1) The resin-embedded sample is conserved, albeit in a sliced-up version. It can be stained in different ways and imaged with different resolutions. (2) As the sections can be post-stained, it is not necessary to use samples strongly block-stained with heavy metals to introduce contrast for SEM imaging or render the tissue blocks conductive. This makes the method applicable to a wide variety of materials and biological questions. Particularly prefixed materials e.g., from biopsy banks and pathology labs, can directly be embedded and reconstructed in 3D. PMID:29630046

High Resolution Chemical Study of ALH84001

NASA Technical Reports Server (NTRS)

Conrad, Pamela G.; Douglas, Susanne; Kuhlman, Kimberly R.

2001-01-01

We have studied the chemistry of a sample of the SNC meteorite ALH84001 using an environmental scanning electron microscope (ESEM) with an energy dispersive chemical analytical detector and a focused ion beam secondary ion mass spectrometer (FIB-SIMS). Here we present the chemical data, both spectra and images, from two techniques that do not require sample preparation with a conductive coating, thus eliminating the possibility of preparation-induced textural artifacts. The FIB-SIMS instrument includes a column optimized for SEM with a quadrupole type mass spectrometer. Its spatial and spectral resolution are 20 nm and 0.4 AMU, respectively. The spatial resolution of the ESEM for chemical analysis is about 100 nm. Limits of detection for both instruments are mass dependent. Both the ESEM and the FIB-SIMS instrument revealed contrasting surficial features; crumbled, weathered appearance of the matrix in some regions as well as a rather ubiquitous presence of euhedral halite crystals, often associated with cracks or holes in the surface of the rock. Other halogen elements present in the vicinity of the NaCl crystals include K and Br. In this report, elemental inventories are shown as mass spectra and as X-ray maps.

Identification of Fragile Microscopic Structures during Mineral Transformations in Wet Supercritical CO2

DOE Office of Scientific and Technical Information (OSTI.GOV)

Arey, Bruce W.; Kovarik, Libor; Qafoku, Odeta

2013-04-01

In this study we examine the nature of highly fragile reaction products that form in low water content super critical carbon dioxide (scCO2) using a combination of scanning electron microscopy/focus ion beam (SEM/FIB), confocal Raman spectroscopy, helium ion microscopy (HeIM), and transmission electron microscopy (TEM). HeIM images show these precipitates to be fragile rosettes that can readily decompose even under slight heating from an electron beam. Using the TEM revealed details on the interfacial structure between the newly formed surface precipitates and the underlying initial solid phases. The detailed microscopic analysis revealed that the growth of the precipitates either followedmore » a tip growth mechanism with precipitates forming directly on the forsterite surface if the initial solid was non-porous (natural forsterite) or growth from the surface of the precipitates where fluid was conducted through the porous (nanoforsterite) agglomerates to the growth center. The mechanism of formation of the hydrated/hydroxylated magnesium carbonate compound (HHMC) phases offers insight into the possible mechanisms of carbonate mineral formation from scCO2 solutions which has recently received a great deal of attention as the result of the potential for CO2 to act as an atmospheric greenhouse gas and impact overall global warming. The techniques used here to examine these fragile structures an also be used to examine a wide range of fragile material surfaces. SEM and FIB technologies have now been brought together in a single instrument, which represents a powerful combination for the studies in biological, geological and materials science.« less

Neuroanatomy from Mesoscopic to Nanoscopic Scales: An Improved Method for the Observation of Semithin Sections by High-Resolution Scanning Electron Microscopy

PubMed Central

Rodríguez, José-Rodrigo; Turégano-López, Marta; DeFelipe, Javier; Merchán-Pérez, Angel

2018-01-01

Semithin sections are commonly used to examine large areas of tissue with an optical microscope, in order to locate and trim the regions that will later be studied with the electron microscope. Ideally, the observation of semithin sections would be from mesoscopic to nanoscopic scales directly, instead of using light microscopy and then electron microscopy (EM). Here we propose a method that makes it possible to obtain high-resolution scanning EM images of large areas of the brain in the millimeter to nanometer range. Since our method is compatible with light microscopy, it is also feasible to generate hybrid light and electron microscopic maps. Additionally, the same tissue blocks that have been used to obtain semithin sections can later be used, if necessary, for transmission EM, or for focused ion beam milling and scanning electron microscopy (FIB-SEM). PMID:29568263

Neuroanatomy from Mesoscopic to Nanoscopic Scales: An Improved Method for the Observation of Semithin Sections by High-Resolution Scanning Electron Microscopy.

PubMed

Rodríguez, José-Rodrigo; Turégano-López, Marta; DeFelipe, Javier; Merchán-Pérez, Angel

2018-01-01

Semithin sections are commonly used to examine large areas of tissue with an optical microscope, in order to locate and trim the regions that will later be studied with the electron microscope. Ideally, the observation of semithin sections would be from mesoscopic to nanoscopic scales directly, instead of using light microscopy and then electron microscopy (EM). Here we propose a method that makes it possible to obtain high-resolution scanning EM images of large areas of the brain in the millimeter to nanometer range. Since our method is compatible with light microscopy, it is also feasible to generate hybrid light and electron microscopic maps. Additionally, the same tissue blocks that have been used to obtain semithin sections can later be used, if necessary, for transmission EM, or for focused ion beam milling and scanning electron microscopy (FIB-SEM).

FIB/SEM technology and high-throughput 3D reconstruction of dendritic spines and synapses in GFP-labeled adult-generated neurons.

PubMed

Bosch, Carles; Martínez, Albert; Masachs, Nuria; Teixeira, Cátia M; Fernaud, Isabel; Ulloa, Fausto; Pérez-Martínez, Esther; Lois, Carlos; Comella, Joan X; DeFelipe, Javier; Merchán-Pérez, Angel; Soriano, Eduardo

2015-01-01

The fine analysis of synaptic contacts is usually performed using transmission electron microscopy (TEM) and its combination with neuronal labeling techniques. However, the complex 3D architecture of neuronal samples calls for their reconstruction from serial sections. Here we show that focused ion beam/scanning electron microscopy (FIB/SEM) allows efficient, complete, and automatic 3D reconstruction of identified dendrites, including their spines and synapses, from GFP/DAB-labeled neurons, with a resolution comparable to that of TEM. We applied this technology to analyze the synaptogenesis of labeled adult-generated granule cells (GCs) in mice. 3D reconstruction of dendritic spines in GCs aged 3-4 and 8-9 weeks revealed two different stages of dendritic spine development and unexpected features of synapse formation, including vacant and branched dendritic spines and presynaptic terminals establishing synapses with up to 10 dendritic spines. Given the reliability, efficiency, and high resolution of FIB/SEM technology and the wide use of DAB in conventional EM, we consider FIB/SEM fundamental for the detailed characterization of identified synaptic contacts in neurons in a high-throughput manner.

FIB/SEM technology and high-throughput 3D reconstruction of dendritic spines and synapses in GFP-labeled adult-generated neurons

PubMed Central

Bosch, Carles; Martínez, Albert; Masachs, Nuria; Teixeira, Cátia M.; Fernaud, Isabel; Ulloa, Fausto; Pérez-Martínez, Esther; Lois, Carlos; Comella, Joan X.; DeFelipe, Javier; Merchán-Pérez, Angel; Soriano, Eduardo

2015-01-01

The fine analysis of synaptic contacts is usually performed using transmission electron microscopy (TEM) and its combination with neuronal labeling techniques. However, the complex 3D architecture of neuronal samples calls for their reconstruction from serial sections. Here we show that focused ion beam/scanning electron microscopy (FIB/SEM) allows efficient, complete, and automatic 3D reconstruction of identified dendrites, including their spines and synapses, from GFP/DAB-labeled neurons, with a resolution comparable to that of TEM. We applied this technology to analyze the synaptogenesis of labeled adult-generated granule cells (GCs) in mice. 3D reconstruction of dendritic spines in GCs aged 3–4 and 8–9 weeks revealed two different stages of dendritic spine development and unexpected features of synapse formation, including vacant and branched dendritic spines and presynaptic terminals establishing synapses with up to 10 dendritic spines. Given the reliability, efficiency, and high resolution of FIB/SEM technology and the wide use of DAB in conventional EM, we consider FIB/SEM fundamental for the detailed characterization of identified synaptic contacts in neurons in a high-throughput manner. PMID:26052271

A Novel Hybrid Ultramicrotomy/FIB-SEM Technique: Preparation of Serial Electron-Transparent Thin Sections of a Hayabusa Grain

NASA Technical Reports Server (NTRS)

Berger, Eve L.; Keller, Lindsay P.

2014-01-01

The Japanese space agency's (JAXA) Hayabusa mission returned the first particulate samples (typically <100micron) from the surface of an asteroid (25143 Itokawa). These precious samples provide important insights into early Solar System processes, but their sizes pose tremendous challenges to coordinated analysis using a variety of nano- and micro-beam techniques. The ability to glean maximal information from individual particles has become increasingly important and depends critically on sample preparation. We developed a hybrid technique combining traditional ultramicrotomy with focused ion beam (FIB) techniques, allowing for more thorough in situ investigations of grain surfaces and interiors. Using this method, we increase the number of FIB-prepared sections that can be recovered from a particle with dimensions on the order of tens of microns. These sections can be subsequently analyzed using a variety of analytical techniques. Particle RA-QD02-0211 is a approx. 40×40×20 micron particle from Itokawa containing olivine and Fe sulfides. It was embedded in low viscosity epoxy and partly sectioned to a depth of approx 10 micron; sections are placed on Cu grids with thin amorphous films for transmission electron microscope (TEM) analyses. With the sample surface partly exposed, the epoxy bullet is trimmed to a height of approx. 5mm to accommodate the allowable dimensions for FIB work (FEI Quanta 600 3D dual beam FIB-SEM). Using a diamond trim knife, the epoxy surrounding the grain is removed on 3 sides (to within a few microns of the grain); the depth of material removed extends well below the bottom of the particle. The sample is attached to an SEM pin mount, the epoxy coated with conductive paint, and the entire assembly coated with approx. 40nm of carbon to eliminate sample charging during FIB work. A protective carbon cap is placed according to the plan for the 15 FIB sections. The central 'spine' of the cap runs perpendicular to the front of the sample, and the 'ribs' protruding from either side run parallel. Each rib indicates the location of a planned FIB section, and the spine contains the final two planned sections. We use a cap with a 4 micron-wide spine and 2micron-wide ribs that have ?3.5 micron of space between them (narrower cuts result in too much re-deposition of material inside the trenches). Using a 30kV, 3nA ion-beam we expose the front surface of the grain and commence milling trenches between sections. Rather than using the typical C-cut to prepare the sample for lift-out, an L-cut is used instead, leaving the sample connected by an interior tab. tab. Sections are lifted out, attached to TEM grids and thinned to electron transparency. TEM analyses show that our hybrid technique preserves both interior and edge features, including surface modifications from exposure to the space environment, such as damaged rims that form in response to solar wind implantation effects and adhering grains. In addition, the FIB sections provide larger areas that are free of fractures and chatter effects in comparison to the microtome thin sections, thus enabling more accurate measurements of solar flare particle track densities that are used to determine the surface exposure age of the particles.

Characterization of Meteorites by Focused Ion Beam Sectioning: Recent Applications to CAIs and Primitive Meteorite Matrices

NASA Technical Reports Server (NTRS)

Christoffersen, Roy; Keller, Lindsay P.; Han, Jangmi; Rahman, Zia; Berger, Eve L.

2015-01-01

Focused ion beam (FIB) sectioning has revolutionized preparation of meteorite samples for characterization by analytical transmission electron microscopy (TEM) and other techniques. Although FIB is not "non-destructive" in the purest sense, each extracted section amounts to no more than nanograms (approximately 500 cubic microns) removed intact from locations precisely controlled by SEM imaging and analysis. Physical alteration of surrounding material by ion damage, fracture or sputter contamination effects is localized to within a few micrometers around the lift-out point. This leaves adjacent material intact for coordinate geochemical analysis by SIMS, microdrill extraction/TIMS and other techniques. After lift out, FIB sections can be quantitatively analyzed by electron microprobe prior to final thinning, synchrotron x-ray techniques, and by the full range of state-of-the-art analytical field-emission scanning transmission electron microscope (FE-STEM) techniques once thinning is complete. Multiple meteorite studies supported by FIB/FE-STEM are currently underway at NASA-JSC, including coordinated analysis of refractory phase assemblages in CAIs and fine-grained matrices in carbonaceous chondrites. FIB sectioning of CAIs has uncovered epitaxial and other overgrowth relations between corundum-hibonite-spinel consistent with hibonite preceding corundum and/or spinel in non-equilibrium condensation sequences at combinations of higher gas pressures, dust-gas enrichments or significant nebular transport. For all of these cases, the ability of FIB to allow for coordination with spatially-associated isotopic data by SIMS provides immense value for constraining the formation scenarios of the particular CAI assemblage. For carbonaceous chondrites matrix material, FIB has allowed us to obtain intact continuous sections of the immediate outer surface of Murchison (CM2) after it has been experimentally ion processed to simulate solar wind space weathering. The surface amorphization and loss of OH produced by the irradiation provides important clues regarding space weathering on primitive asteroids such as the OSIRIS-Rex target 101955 Bennu.

A two scale analysis of tight sandstones

NASA Astrophysics Data System (ADS)

Adler, P. M.; Davy, C. A.; Song, Y.; Troadec, D.; Hauss, G.; Skoczylas, F.

2015-12-01

Tight sandstones have a low porosity and a very small permeability K. Available models for K do not compare well with measurements. These sandstones are made of SiO_2 grains, with a typical size of several hundreds of micron. These grains are separated by a network of micro-cracks, with sizes ranging between microns down to tens of nm. Therefore, the structure can be schematized by Voronoi polyhedra separated by plane and permeable polygonal micro-cracks. Our goal is to estimate K based on a two scale analysis and to compare the results to measurements. For a particular sample [2], local measurements on several scales include FIB/SEM [3], CMT and 2D SEM. FIB/SEM is selected because the peak pore size given by Mercury Intrusion Porosimetry is of 350nm. FIB/SEM imaging (with 50 nm voxel size) identifies an individual crack of 180nm average opening, whereas CMT provides a connected porosity (individual crack) for 60 nm voxel size, of 4 micron average opening. Numerical modelling is performed by combining the micro-crack network scale (given by 2D SEM) and the 3D micro-crack scale (given by either FIB/SEM or CMT). Estimates of the micro-crack density are derived from 2D SEM trace maps by counting the intersections with scanlines, the surface density of traces, and the number of fracture intersections. K is deduced by using a semi empirical formula valid for identical, isotropic and uniformly distributed fractures [1]. This value is proportional to the micro-crack transmissivity sigma. Sigma is determined by solving the Stokes equation in the micro-cracks measured by FIB/SEM or CMT. K is obtained by combining the two previous results. Good correlation with measured values on centimetric plugs is found when using sigma from CMT data. The results are discussed and further research is proposed. [1] Adler et al, Fractured porous media, Oxford Univ. Press, 2012. [2] Duan et al, Int. J. Rock Mech. Mining Sci., 65, p75, 2014. [3] Song et al, Marine and Petroleum Eng., 65, p63, 2015.

Transmission Kikuchi diffraction and transmission electron forescatter imaging of electropolished and FIB manufactured TEM specimens

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zieliński, W., E-mail: wiziel@inmat.pw.edu.pl; Płociński, T.; Kurzydłowski, K.J.

2015-06-15

We present a study of the efficiency of the utility of scanning electron microscope (SEM)-based transmission methods for characterizing grain structure in thinned bulk metals. Foils of type 316 stainless steel were prepared by two methods commonly used for transmission electron microscopy — double-jet electropolishing and focused ion beam milling. A customized holder allowed positioning of the foils in a configuration appropriate for both transmission electron forward scatter diffraction, and for transmission imaging by the use of a forescatter detector with two diodes. We found that both crystallographic orientation maps and dark-field transmitted images could be obtained for specimens preparedmore » by either method. However, for both methods, preparation-induced artifacts may affect the quality or accuracy of transmission SEM data, especially those acquired by the use of transmission Kikuchi diffraction. Generally, the quality of orientation data was better for specimens prepared by electropolishing, due to the absence of ion-induced damage. - Highlights: • The transmission imaging and diffraction techniques are emerging in scanning electron microscopy (SEM) as promising new field of materials characterization. • The manuscript titled: “Transmission Kikuchi Diffraction and Transmission Electron Forescatter Imaging of Electropolished and FIB Manufactured TEM Specimens” documents how different specimen thinning procedures can effect efficiency of transmission Kikuchi diffraction and transmission electron forescatter imaging. • The abilities to make precision crystallographic orientation maps and dark-field images in transmission was studied on electropolished versus focus ion beam manufactured TEM specimens. • Depending on the need, electropolished and focused ion beam technique may produce suitable specimens for transmission imaging and diffraction in SEM.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xu, C. Shan; Hayworth, Kenneth J.; Lu, Zhiyuan

Focused Ion Beam Scanning Electron Microscopy (FIB-SEM) can automatically generate 3D images with superior z-axis resolution, yielding data that needs minimal image registration and related post-processing. Obstacles blocking wider adoption of FIB-SEM include slow imaging speed and lack of long-term system stability, which caps the maximum possible acquisition volume. Here, we present techniques that accelerate image acquisition while greatly improving FIB-SEM reliability, allowing the system to operate for months and generating continuously imaged volumes > 10 6 ?m 3 . These volumes are large enough for connectomics, where the excellent z resolution can help in tracing of small neuronal processesmore » and accelerate the tedious and time-consuming human proofreading effort. Even higher resolution can be achieved on smaller volumes. We present example data sets from mammalian neural tissue, Drosophila brain, and Chlamydomonas reinhardtii to illustrate the power of this novel high-resolution technique to address questions in both connectomics and cell biology.« less

The Effect of Microstructure On Transport Properties of Porous Electrodes

NASA Astrophysics Data System (ADS)

Peterson, Serena W.

The goal of this work is to further understand the relationships between porous electrode microstructure and mass transport properties. This understanding allows us to predict and improve cell performance from fundamental principles. The investigated battery systems are the widely used rechargeable Li-ion battery and the non-rechargeable alkaline battery. This work includes three main contributions in the battery field listed below. Direct Measurement of Effective Electronic Transport in Porous Li-ion Electrodes. An accurate assessment of the electronic conductivity of electrodes is necessary for understanding and optimizing battery performance. The bulk electronic conductivity of porous LiCoO2-based cathodes was measured as a function of porosity, pressure, carbon fraction, and the presence of an electrolyte. The measurements were performed by delamination of thin-film electrodes from their aluminum current collectors and by use of a four-line probe. Imaging and Correlating Microstructure To Conductivity. Transport properties of porous electrodes are strongly related to microstructure. An experimental 3D microstructure is needed not only for computation of direct transport properties, but also for a detailed electrode microstructure characterization. This work utilized X-ray tomography and focused ion beam (FIB)/scanning electron microscopy (SEM) to obtain the 3D structures of alkaline battery cathodes. FIB/SEM has the advantage of detecting carbon additives; thus, it was the main tomography tool employed. Additionally, protocols and techniques for acquiring, processing and segmenting series of FIB/SEM images were developed as part of this work. FIB/SEM images were also used to correlate electrodes' microstructure to their respective conductivities for both Li-ion and alkaline batteries. Electrode Microstructure Metrics and the 3D Stochastic Grid Model. A detailed characterization of microstructure was conducted in this work, including characterization of the volume fraction, nearest neighbor probability, domain size distribution, shape factor, and Fourier transform coefficient. These metrics are compared between 2D FIB/SEM, 3D FIB/SEM and X-ray structures. Among those metrics, the first three metrics are used as a basis for SG model parameterization. The 3D stochastic grid (SG) model is based on Monte Carlo techniques, in which a small set of fundamental inter-domain parameters are used to generate structures. This allows us to predict electrode microstructure and its effects on both electronic and ionic properties.

Three-dimensional analysis of somatic mitochondrial dynamics in fission-deficient injured motor neurons using FIB/SEM.

PubMed

Tamada, Hiromi; Kiryu-Seo, Sumiko; Hosokawa, Hiroki; Ohta, Keisuke; Ishihara, Naotada; Nomura, Masatoshi; Mihara, Katsuyoshi; Nakamura, Kei-Ichiro; Kiyama, Hiroshi

2017-08-01

Mitochondria undergo morphological changes through fusion and fission for their quality control, which are vital for neuronal function. In this study, we examined three-dimensional morphologies of mitochondria in motor neurons under normal, nerve injured, and nerve injured plus fission-impaired conditions using the focused ion beam/scanning electron microscopy (FIB/SEM), because the FIB/SEM technology is a powerful tool to demonstrate both 3D images of whole organelle and the intra-organellar structure simultaneously. Crossing of dynamin-related protein 1 (Drp1) gene-floxed mice with neuronal injury-specific Cre driver mice, Atf3:BAC Tg mice, allowed for Drp1 ablation specifically in injured neurons. FIB/SEM analysis demonstrated that somatic mitochondrial morphologies in motor neurons were not altered before or after nerve injury. However, the fission impairment resulted in prominent somatic mitochondrial enlargement, which initially induced complex morphologies with round regions and long tubular processes, subsequently causing a decrease in the number of processes and further enlargement of the round regions, which eventually resulted in big spheroidal mitochondria without processes. The abnormal mitochondria exhibited several degradative morphologies: local or total cristae collapse, vacuolization, and mitophagy. These suggest that mitochondrial fission is crucial for maintaining mitochondrial integrity in injured motor neurons, and multiple forms of mitochondria degradation may accelerate neuronal degradation. © 2017 Wiley Periodicals, Inc.

FIB and MIP: understanding nanoscale porosity in molecularly imprinted polymers via 3D FIB/SEM tomography.

PubMed

Neusser, G; Eppler, S; Bowen, J; Allender, C J; Walther, P; Mizaikoff, B; Kranz, C

2017-10-05

We present combined focused ion beam/scanning electron beam (FIB/SEM) tomography as innovative method for differentiating and visualizing the distribution and connectivity of pores within molecularly imprinted polymers (MIPs) and non-imprinted control polymers (NIPs). FIB/SEM tomography is used in cell biology for elucidating three-dimensional structures such as organelles, but has not yet been extensively applied for visualizing the heterogeneity of nanoscopic pore networks, interconnectivity, and tortuosity in polymers. To our best knowledge, the present study is the first application of this strategy for analyzing the nanoscale porosity of MIPs. MIPs imprinted for propranolol - and the corresponding NIPs - were investigated establishing FIB/SEM tomography as a viable future strategy complementing conventional isotherm studies. For visualizing and understanding the properties of pore networks in detail, polymer particles were stained with osmium tetroxide (OsO 4 ) vapor, and embedded in epoxy resin. Staining with OsO 4 provides excellent contrast during high-resolution SEM imaging. After optimizing the threshold to discriminate between the stained polymer matrix, and pores filled with epoxy resin, a 3D model of the sampled volume may be established for deriving not only the pore volume and pore surface area, but also to visualize the interconnectivity and tortuosity of the pores within the sampled polymer volume. Detailed studies using different types of cross-linkers and the effect of hydrolysis on the resulting polymer properties have been investigated. In comparison of MIP and NIP, it could be unambiguously shown that the interconnectivity of the visualized pores in MIPs is significantly higher vs. the non-imprinted polymer, and that the pore volume and pore area is 34% and approx. 35% higher within the MIP matrix. This confirms that the templating process not only induces selective binding sites, but indeed also affects the physical properties of such polymers down to the nanoscale, and that additional chemical modification, e.g., via hydrolysis clearly affects that nature of the polymer.

Micro-fabric damages in Boom Clay inferred from cryo-BIB-SEM experiment: recent results

NASA Astrophysics Data System (ADS)

Desbois, Guillaume; Schmatz, Joyce; Klaver, Jop; Urai, Janos L.

2017-04-01

The Boom Clay is considered as a potential host rock in Belgium for nuclear waste disposal in a deep geological formation. One of the keys to understand the long-term performance of such a host rock is the fundamental understanding of coupling between microstructural evolution, poromechanical behaviour and the state of hydration of the system. At in situ conditions, Boom Clay is a nearly water-saturated (>94%) clay-rich geomaterial. Subsequently, for measurement of mechanical and transport properties in laboratory, cores of Boom Clay are vacuum-packed in Al-coated-poly-ethylene barrier foil to be best preserved at original hydric state. Because clay microstructures are very sensitive to dehydration, the validity of investigations done on such preserved or/and dried samples is often questionable. Desbois et al. (2009, 2013, 2014) showed the possibility to image fluid-filled porosity in Boom Clay, by using the FIB-cryo-SEM (FIB: Focussed Ion Beam) and FIB-cryo-SEM (BIB: Broad Ion Beam) techniques. However, surprisingly in Desbois et al. (2014), BIB-cryo-SEM experiments on Boom Clay, shown that the majority of the pores were fluid-free, contrasting with result in Desbois et al. (2009). In Desbois et al. (2014), several reasons were discussed to explain such discrepancies. The likely ones are the sealing efficiency of the Al-barrier foil at long term and the volume expansion due to the release of in-situ stress after core extraction, contributing both to dehydration and microfabric damage. This contribution presents the newest results based on cryo-BIB-SEM. Small pieces (30 mm3) of Boom Clay were preserved in liquid nitrogen after the core extraction at the MOL/Dessel Underground Research Laboratory in Belgium. A maximum of ten minutes time span was achieved between opening the core, the sub-sample extraction and the quenching of sub-samples in liquid nitrogen. First results show that all pores visible at cryo-SEM resolution are water saturated. However, water-filled micro-cracks are also present and they are interpreted to result from the releasing of in-situ stress after the core extraction. Moreover, the comparison of the clay micro-fabrics in the same preserved and dried sample suggests collapsing of the clay aggregates' pores in dried sample. These newest results are still preliminary and they need to be analysed in more details. However, if they are confirmed they may be important input to discuss about the validity of measurement of mechanical and transport properties done in laboratory. Desbois G., Urai J.L. and Kukla P.A. (2009). Morphology of the pore space in claystones - evidence from BIB/FIB ion beam sectioning and cryo-SEM observations. E-Earth, 4 :15-22. Desbois G., J.L. Urai, F. Pérez-Willard, Z. Radi, S. van Offern, I. Burkart, P.A. Kukla, U. Wollenberg (2013). Argon broad ion beam tomography in a cryogenic scanning electron microscope: a novel tool for the investigation of representative microstructures in sedimentary rocks containing pore fluid. Journal of Microscopy, 249(3): 215-235. Desbois G., Urai J.L., Hemes S., Brassinnes S., De Craen M., Sillen X. (2014). Nanometer-scale pore fluid distribution and drying damage in preserved clay cores from Belgian clay formations inferred by BIB-cryo-SEM. Engineering Geology, 170:117-131.

Ultrastructurally-smooth thick partitioning and volume stitching for larger-scale connectomics

PubMed Central

Hayworth, Kenneth J.; Xu, C. Shan; Lu, Zhiyuan; Knott, Graham W.; Fetter, Richard D.; Tapia, Juan Carlos; Lichtman, Jeff W.; Hess, Harald F.

2015-01-01

FIB-SEM has become an essential tool for studying neural tissue at resolutions below 10×10×10 nm, producing datasets superior for automatic connectome tracing. We present a technical advance, ultrathick sectioning, which reliably subdivides embedded tissue samples into chunks (20 µm thick) optimally sized and mounted for efficient, parallel FIB-SEM imaging. These chunks are imaged separately and then ‘volume stitched’ back together, producing a final 3D dataset suitable for connectome tracing. PMID:25686390

Seeing a Mycobacterium-Infected Cell in Nanoscale 3D: Correlative Imaging by Light Microscopy and FIB/SEM Tomography

PubMed Central

Beckwith, Marianne Sandvold; Beckwith, Kai Sandvold; Sikorski, Pawel; Skogaker, Nan Tostrup

2015-01-01

Mycobacteria pose a threat to the world health today, with pathogenic and opportunistic bacteria causing tuberculosis and non-tuberculous disease in large parts of the population. Much is still unknown about the interplay between bacteria and host during infection and disease, and more research is needed to meet the challenge of drug resistance and inefficient vaccines. This work establishes a reliable and reproducible method for performing correlative imaging of human macrophages infected with mycobacteria at an ultra-high resolution and in 3D. Focused Ion Beam/Scanning Electron Microscopy (FIB/SEM) tomography is applied, together with confocal fluorescence microscopy for localization of appropriately infected cells. The method is based on an Aclar poly(chloro-tri-fluoro)ethylene substrate, micropatterned into an advantageous geometry by a simple thermomoulding process. The platform increases the throughput and quality of FIB/SEM tomography analyses, and was successfully applied to detail the intracellular environment of a whole mycobacterium-infected macrophage in 3D. PMID:26406896

Comparison of mechanical characteristics of focused ion beam fabricated silicon nanowires

NASA Astrophysics Data System (ADS)

Ina, Ginnosuke; Fujii, Tatsuya; Kozeki, Takahiro; Miura, Eri; Inoue, Shozo; Namazu, Takahiro

2017-06-01

In this study, we investigate the effects of focused ion beam (FIB)-induced damage and specimen size on the mechanical properties of Si nanowires (NWs) by a microelectromechanical system (MEMS)-based tensile testing technique. By an FIB fabrication technique, three types of Si NWs, which are as-FIB-fabricated, annealed, and FIB-implanted NWs, are prepared. A sacrificial-oxidized NW is also prepared to compare the mechanical properties of these FIB-based NWs. The quasi-static uniaxial tensile tests of all the NWs are conducted by scanning electron microscopy (SEM). The fabrication process and specimen size dependences on Young’s modulus and fracture strength are observed. Annealing is effective for improving the Young’s modulus of the FIB-damaged Si. Transmission electron microscopy (TEM) suggests that the mechanism behind the process dependence on the mechanical characteristics is related to the crystallinity of the FIB-damaged portion.

Solar Flare Track Exposure Ages in Regolith Particles: A Calibration for Transmission Electron Microscope Measurements

NASA Technical Reports Server (NTRS)

Berger, Eve L.; Keller, Lindsay P.

2015-01-01

Mineral grains in lunar and asteroidal regolith samples provide a unique record of their interaction with the space environment. Space weathering effects result from multiple processes including: exposure to the solar wind, which results in ion damage and implantation effects that are preserved in the rims of grains (typically the outermost 100 nm); cosmic ray and solar flare activity, which result in track formation; and impact processes that result in the accumulation of vapor-deposited elements, impact melts and adhering grains on particle surfaces. Determining the rate at which these effects accumulate in the grains during their space exposure is critical to studies of the surface evolution of airless bodies. Solar flare energetic particles (mainly Fe-group nuclei) have a penetration depth of a few millimeters and leave a trail of ionization damage in insulating materials that is readily observable by transmission electron microscope (TEM) imaging. The density of solar flare particle tracks is used to infer the length of time an object was at or near the regolith surface (i.e., its exposure age). Track measurements by TEM methods are routine, yet track production rate calibrations have only been determined using chemical etching techniques [e.g., 1, and references therein]. We used focused ion beam-scanning electron microscope (FIB-SEM) sample preparation techniques combined with TEM imaging to determine the track density/exposure age relations for lunar rock 64455. The 64455 sample was used earlier by [2] to determine a track production rate by chemical etching of tracks in anorthite. Here, we show that combined FIB/TEM techniques provide a more accurate determination of a track production rate and also allow us to extend the calibration to solar flare tracks in olivine.

Three-Phase 3D Reconstruction of a LiCoO 2 Cathode via FIB-SEM Tomography

DOE PAGES

Liu, Zhao; Chen-Wiegart, Yu-chen K.; Wang, Jun; ...

2016-01-14

Three-phase three-dimensional (3D) microstructural reconstructions of lithium-ion battery electrodes are critical input for 3D simulations of electrode lithiation/delithiation, which provide a detailed understanding of battery operation. In this report, 3D images of a LiCoO 2electrode are achieved using focused ion beam-scanning electron microscopy (FIB-SEM), with clear contrast among the three phases: LiCoO 2particles, carbonaceous phases (carbon and binder) and the electrolyte space. The good contrast was achieved by utilizing an improved FIB-SEM sample preparation method that combined infiltration of the electrolyte space with a low-viscosity silicone resin and triple ion-beam polishing. Morphological parameters quantified include phase volume fraction, surface area,more » feature size distribution, connectivity, and tortuosity. Electrolyte tortuosity was determined using two different geometric calculations that were in good agreement. In conclusion, the electrolyte tortuosity distribution versus position within the electrode was found to be highly inhomogeneous; this will lead to inhomogeneous electrode lithiation/delithiation at high C-rates that could potentially cause battery degradation.« less

Improving microstructural quantification in FIB/SEM nanotomography.

PubMed

Taillon, Joshua A; Pellegrinelli, Christopher; Huang, Yi-Lin; Wachsman, Eric D; Salamanca-Riba, Lourdes G

2018-01-01

FIB/SEM nanotomography (FIB-nt) is a powerful technique for the determination and quantification of the three-dimensional microstructure in subsurface features. Often times, the microstructure of a sample is the ultimate determiner of the overall performance of a system, and a detailed understanding of its properties is crucial in advancing the materials engineering of a resulting device. While the FIB-nt technique has developed significantly in the 15 years since its introduction, advanced nanotomographic analysis is still far from routine, and a number of challenges remain in data acquisition and post-processing. In this work, we present a number of techniques to improve the quality of the acquired data, together with easy-to-implement methods to obtain "advanced" microstructural quantifications. The techniques are applied to a solid oxide fuel cell cathode of interest to the electrochemistry community, but the methodologies are easily adaptable to a wide range of material systems. Finally, results from an analyzed sample are presented as a practical example of how these techniques can be implemented. Copyright © 2017 Elsevier B.V. All rights reserved.

Evaluating focused ion beam patterning for position-controlled nanowire growth using computer vision

NASA Astrophysics Data System (ADS)

Mosberg, A. B.; Myklebost, S.; Ren, D.; Weman, H.; Fimland, B. O.; van Helvoort, A. T. J.

2017-09-01

To efficiently evaluate the novel approach of focused ion beam (FIB) direct patterning of substrates for nanowire growth, a reference matrix of hole arrays has been used to study the effect of ion fluence and hole diameter on nanowire growth. Self-catalyzed GaAsSb nanowires were grown using molecular beam epitaxy and studied by scanning electron microscopy (SEM). To ensure an objective analysis, SEM images were analyzed with computer vision to automatically identify nanowires and characterize each array. It is shown that FIB milling parameters can be used to control the nanowire growth. Lower ion fluence and smaller diameter holes result in a higher yield (up to 83%) of single vertical nanowires, while higher fluence and hole diameter exhibit a regime of multiple nanowires. The catalyst size distribution and placement uniformity of vertical nanowires is best for low-value parameter combinations, indicating how to improve the FIB parameters for positioned-controlled nanowire growth.

Quantitative analysis of nano-pore geomaterials and representative sampling for digital rock physics

NASA Astrophysics Data System (ADS)

Yoon, H.; Dewers, T. A.

2014-12-01

Geomaterials containing nano-pores (e.g., shales and carbonate rocks) have become increasingly important for emerging problems such as unconventional gas and oil resources, enhanced oil recovery, and geologic storage of CO2. Accurate prediction of coupled geophysical and chemical processes at the pore scale requires realistic representation of pore structure and topology. This is especially true for chalk materials, where pore networks are small and complex, and require characterization at sub-micron scale. In this work, we apply laser scanning confocal microscopy to characterize pore structures and microlithofacies at micron- and greater scales and dual focused ion beam-scanning electron microscopy (FIB-SEM) for 3D imaging of nanometer-to-micron scale microcracks and pore distributions. With imaging techniques advanced for nano-pore characterization, a problem of scale with FIB-SEM images is how to take nanometer scale information and apply it to the thin-section or larger scale. In this work, several texture characterization techniques including graph-based spectral segmentation, support vector machine, and principal component analysis are applied for segmentation clusters represented by 1-2 FIB-SEM samples per each cluster. Geometric and topological properties are analyzed and lattice-Boltzmann method (LBM) is used to obtain permeability at several different scales. Upscaling of permeability to the Darcy scale (e.g., the thin-section scale) with image dataset will be discussed with emphasis on understanding microfracture-matrix interaction, representative volume for FIB-SEM sampling, and multiphase flow and reactive transport. Funding from the DOE Basic Energy Sciences Geosciences Program is gratefully acknowledged. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

Nanoscale Origins of the Size Effect in the Compression Response of Single Crystal Ni-Base Superalloy Micro-Pillars

PubMed Central

Ying, Siqi; Ma, Lifeng; Papadaki, Chrysanthi; Romano Brandt, Leon; Zhang, Hongjia

2018-01-01

Nickel superalloys play a pivotal role in enabling power-generation devices on land, sea, and in the air. They derive their strength from coherent cuboidal precipitates of the ordered γ’ phase that is different from the γ matrix in composition, structure and properties. In order to reveal the correlation between elemental distribution, dislocation glide and the plastic deformation of micro- and nano-sized volumes of a nickel superalloy, a combined in situ nanoindentation compression study was carried out with a scanning electron microscope (SEM) on micro- and nano-pillars fabricated by focused ion beam (FIB) milling of Ni-base superalloy CMSX4. The observed mechanical response (hardening followed by softening) was correlated with the progression of crystal slip that was revealed using FIB nano-tomography and energy-dispersive spectroscopy (EDS) elemental mapping. A hypothesis was put forward that the dependence of material strength on the size of the sample (micropillar diameter) is correlated with the characteristic dimension of the structural units (γ’ precipitates). By proposing two new dislocation-based models, the results were found to be described well by a new parameter-free Hall–Petch equation. PMID:29621189

Microstructural Study of Micron-Sized Craters Simulating Stardust Impacts in Aluminum 1100 Targets

NASA Technical Reports Server (NTRS)

Leroux, Hugues; Borg, Janet; Troadec, David; Djouadi, Zahia; Horz, Friedrich

2006-01-01

Various microscopic techniques were used to characterize experimental micro- craters in aluminium foils to prepare for the comprehensive analysis of the cometary and interstellar particle impacts in aluminium foils to be returned by the Stardust mission. First, SEM (Scanning Electron Microscopy) and EDS (Energy Dispersive X-ray Spectroscopy) were used to study the morphology of the impact craters and the bulk composition of the residues left by soda-lime glass impactors. A more detailed structural and compositional study of impactor remnants was then performed using TEM (Transmission Electron Microscopy), EDS, and electron diffraction methods. The TEM samples were prepared by Focused Ion Beam (FIB) methods. This technique proved to be especially valuable in studying impact crater residues and impact crater morphology. Finally, we also showed that InfraRed microscopy (IR) can be a quick and reliable tool for such investigations. The combination of all of these tools enables a complete microscopic characterization of the craters.

Synthesis of alumina ceramic encapsulation for self-healing materials on thermal barrier coating

NASA Astrophysics Data System (ADS)

Golim, O. P.; Prastomo, N.; Izzudin, H.; Hastuty, S.; Sundawa, R.; Sugiarti, E.; Thosin, K. A. Z.

2018-03-01

Durability of Thermal Barrier Coating or TBC can be optimized by inducing Self-Healing capabilities with intermetallic materials MoSi2. Nevertheless, high temperature operation causes the self-healing materials to become oxidized and lose its healing capabilities. Therefore, a method to introduce ceramic encapsulation for MoSi2 is needed to protect it from early oxidation. The encapsulation process is synthesized through a simple precipitation method with colloidal aluminum hydroxide as precursor and variations on calcination process. Semi-quantitative analysis on the synthesized sample is done by using X-ray diffraction (XRD) method. Meanwhile, qualitative analysis on the morphology of the encapsulation was carried out by using Scanning Electron Microscope (SEM) and Field Emission Scanning Electron Microscope (FESEM) equipped with dual Focus Ion Beam (FIB). The result of the experiment shows that calcination process significantly affects the final characteristic of encapsulation. The optimum encapsulation process was synthesized by colloidal aluminum hydroxide as a precursor, with a double step calcination process in low pressure until 900 °C.

Cryo-FIB-SEM serial milling and block face imaging: Large volume structural analysis of biological tissues preserved close to their native state.

PubMed

Vidavsky, Netta; Akiva, Anat; Kaplan-Ashiri, Ifat; Rechav, Katya; Addadi, Lia; Weiner, Steve; Schertel, Andreas

2016-12-01

Many important biological questions can be addressed by studying in 3D large volumes of intact, cryo fixed hydrated tissues (⩾10,000μm 3 ) at high resolution (5-20nm). This can be achieved using serial FIB milling and block face surface imaging under cryo conditions. Here we demonstrate the unique potential of the cryo-FIB-SEM approach using two extensively studied model systems; sea urchin embryos and the tail fin of zebrafish larvae. We focus in particular on the environment of mineral deposition sites. The cellular organelles, including mitochondria, Golgi, ER, nuclei and nuclear pores are made visible by the image contrast created by differences in surface potential of different biochemical components. Auto segmentation and/or volume rendering of the image stacks and 3D reconstruction of the skeleton and the cellular environment, provides a detailed view of the relative distribution in space of the tissue/cellular components, and thus of their interactions. Simultaneous acquisition of secondary and back-scattered electron images adds additional information. For example, a serial view of the zebrafish tail reveals the presence of electron dense mineral particles inside mitochondrial networks extending more than 20μm in depth in the block. Large volume imaging using cryo FIB SEM, as demonstrated here, can contribute significantly to the understanding of the structures and functions of diverse biological tissues. Copyright © 2016 Elsevier Inc. All rights reserved.

Single organelle dynamics linked to 3D structure by correlative live-cell imaging and 3D electron microscopy.

PubMed

Fermie, Job; Liv, Nalan; Ten Brink, Corlinda; van Donselaar, Elly G; Müller, Wally H; Schieber, Nicole L; Schwab, Yannick; Gerritsen, Hans C; Klumperman, Judith

2018-05-01

Live-cell correlative light-electron microscopy (live-cell-CLEM) integrates live movies with the corresponding electron microscopy (EM) image, but a major challenge is to relate the dynamic characteristics of single organelles to their 3-dimensional (3D) ultrastructure. Here, we introduce focused ion beam scanning electron microscopy (FIB-SEM) in a modular live-cell-CLEM pipeline for a single organelle CLEM. We transfected cells with lysosomal-associated membrane protein 1-green fluorescent protein (LAMP-1-GFP), analyzed the dynamics of individual GFP-positive spots, and correlated these to their corresponding fine-architecture and immediate cellular environment. By FIB-SEM we quantitatively assessed morphological characteristics, like number of intraluminal vesicles and contact sites with endoplasmic reticulum and mitochondria. Hence, we present a novel way to integrate multiple parameters of subcellular dynamics and architecture onto a single organelle, which is relevant to address biological questions related to membrane trafficking, organelle biogenesis and positioning. Furthermore, by using CLEM to select regions of interest, our method allows for targeted FIB-SEM, which significantly reduces time required for image acquisition and data processing. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Microstructural analysis of 800H steel exposed at test operation in HTHL by using FIB-SEM and HRTEM techniques

NASA Astrophysics Data System (ADS)

Marušáková, Daniela; Bublíková, Petra; Berka, Jan; Vávrovcová, Zuzana; Burda, Jaroslav

2017-09-01

To understand the degradation process of metal materials which are used in power engineering, appropriate evaluation procedure is necessary to ensure. In that order, the degradation of alloy 800H during the first period of test operation in High Temperature Helium Loop (HTHL) was tested. Experiment was carried out in atmosphere of pure technical helium with purity 4.6 containing only residual concentration of moisture up to 300 vppm. Parameters during the operation test were not constant, process was interrupted several times. The maximum temperature on specimens during this period was 750 °C, average temperature was 460 °C, gas pressure ranged from 3 to 6 MPa and gas flow from 3 to 9 gs-1. Total duration of the test was 264 h. After the exposure the degradation of specimens was investigated by Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). Using the technique of Focused Ion Beam (FIB) integrated within SEM the transparent samples with quality surface parameters were obtained for TEM analysis. FIB technique in combination with High Resolution TEM ensured the guaranteed methodology of exposed sample preparation and precise description of changes in this kind of material.

Extremely thin layer plastification for focused-ion beam scanning electron microscopy: an improved method to study cell surfaces and organelles of cultured cells.

PubMed

VAN Donselaar, E G; Dorresteijn, B; Popov-Čeleketić, D; VAN DE Wetering, W J; Verrips, T C; Boekhout, T; Schneijdenberg, C T W M; Xenaki, A T; VAN DER Krift, T P; Müller, W H

2018-03-25

Since the recent boost in the usage of electron microscopy in life-science research, there is a great need for new methods. Recently minimal resin embedding methods have been successfully introduced in the sample preparation for focused-ion beam scanning electron microscopy (FIB-SEM). In these methods several possibilities are given to remove as much resin as possible from the surface of cultured cells or multicellular organisms. Here we introduce an alternative way in the minimal resin embedding method to remove excess of resin from two widely different cell types by the use of Mascotte filter paper. Our goal in correlative light and electron microscopic studies of immunogold-labelled breast cancer SKBR3 cells was to visualise gold-labelled HER2 plasma membrane proteins as well as the intracellular structures of flat and round cells. We found a significant difference (p < 0.001) in the number of gold particles of selected cells per 0.6 μm 2 cell surface: on average a flat cell contained 2.46 ± 1.98 gold particles, and a round cell 5.66 ± 2.92 gold particles. Moreover, there was a clear difference in the subcellular organisation of these two cells. The round SKBR3 cell contained many organelles, such as mitochondria, Golgi and endoplasmic reticulum, when compared with flat SKBR3 cells. Our next goal was to visualise crosswall associated organelles, septal pore caps, of Rhizoctonia solani fungal cells by the combined use of a heavy metal staining and our extremely thin layer plastification (ETLP) method. At low magnifications this resulted into easily finding septa which appeared as bright crosswalls in the back-scattered electron mode in the scanning electron microscope. Then, a septum was selected for FIB-SEM. Cross-sectioned views clearly revealed the perforate septal pore cap of R. solani next to other structures, such as mitochondria, endoplasmic reticulum, lipid bodies, dolipore septum, and the pore channel. As the ETLP method was applied on two widely different cell types, the use of the ETLP method will be beneficial to correlative studies of other cell model systems and multicellular organisms. © 2018 The Authors. Journal of Microscopy published by JohnWiley & Sons Ltd on behalf of Royal Microscopical Society.

FE-SEM, FIB and TEM Study of Surface Deposits of Apollo 15 Green Glass Volcanic Spherules

NASA Technical Reports Server (NTRS)

Ross, Daniel K.; Thomas-Keprta, K. L.; Rahman, Z.; Wentworth, S. J.; McKay, D. S.

2011-01-01

Surface deposits on lunar pyroclastic green (Apollo 15) and orange (Apollo 17) glass spherules have been attributed to condensation from the gas clouds that accompanied fire-fountain eruptions. The fire fountains cast molten lava high above the lunar surface and the silicate melt droplets quenched before landing producing the glass beads. Early investigations showed that these deposits are rich in sulfur and zinc. The deposits are extremely fine-grained and thin, so that it was never possible to determine their chemical compositions cleanly by SEM/EDX or electron probe x-ray analysis because most of the excited volume was in the under-lying silicate glass. We are investigating the surface deposits by TEM, using focused ion beam (FIB) microscopy to extract and thin the surface deposits. Here we report on chemical mapping of a FIB section of surface deposits of an Apollo green glass bead 15401using the ultra-high resolution JEOL 2500 STEM located at NASA Johnson Space Center.

Advanced Characterization of Rare Earth Elements in Coal Utilization Byproducts

NASA Astrophysics Data System (ADS)

Verba, C.; Scott, M.; Dieterich, M.; Poston, J.; Collins, K.

2016-12-01

Rare earth elements (REE) in various forms (e.g., crystalline mineral phases; adsorbed/absorbed state on and into organic macerals, neoformed glass from flyash or bottom ash) from domestic feedstocks such as coal deposits to coal utilization byproducts (CUB) have the potential to reduce foreign REE dependence and increase domestic resource security. Characterization is critical for understanding environmental risks related to their fate and transport as well as determining the most practical and economical techniques for concentrating the REE and converting them into chemical stocks for manufacturing. Several complementary electron microscopy (SEM-EDS, EPMA-WDS, FIB-SEM, cathodoluminescence, and XRD) and post image processing techniques were used to understand REE transition from coal to CUB. Sites of interest were identified and imaged and respective elemental x-ray maps acquired and montaged. Pixel classification of SEM imagers was completed using image analysis techniques to quantify the distribution of REE associated features. Quantitative elemental analysis of phases were completed using EMPA-WDS followed by FIB-SEM. The FIB-SEM results were reconstructed into 3D volumes and features of interest (e.g. monazite) were analyzed to determine the structure and volumetric estimation of REEs and thus predict detrital REE phases to ICP-MS results. Trace minerals were identified as pyrite, zircon, REE-phosphates' (monazite, xenotime), and barite within the coal tailings. In CUB, amorphous aluminosilicates, iron oxide cenospheres, and calcium oxides were present; monazite appear to be unaltered and unaffected by the combustion process in these samples. Thermal decomposition may have occurred due to presence of detrital zircon and xenotime and subsequent thin Ca-oxide coating enriched in trace REEs.

Automated SEM and TEM sample preparation applied to copper/low k materials

NASA Astrophysics Data System (ADS)

Reyes, R.; Shaapur, F.; Griffiths, D.; Diebold, A. C.; Foran, B.; Raz, E.

2001-01-01

We describe the use of automated microcleaving for preparation of both SEM and TEM samples as done by SELA's new MC500 and TEMstation tools. The MC500 is an automated microcleaving tool that is capable of producing cleaves with 0.25 μm accuracy resulting in SEM-ready samples. The TEMstation is capable of taking a sample output from the MC500 (or from SELA's earlier MC200 tool) and producing a FIB ready slice of 25±5 μm, mounted on a TEM-washer and ready for FIB thinning to electron transparency for TEM analysis. The materials selected for the tool set evaluation mainly included the Cu/TaN/HOSP low-k system. The paper is divided into three sections, experimental approach, SEM preparation and analysis of HOSP low-k, and TEM preparation and analysis of Cu/TaN/HOSP low-k samples. For the samples discussed, data is presented to show the quality of preparation provided by these new automated tools.

Organic Aggregates with (delta)D and delta(sup 15)N Anomalies in the Zag Clast Revealed by STXM and NanoSIMS

NASA Technical Reports Server (NTRS)

Kebukawa, Y.; Ito, M.; Zolensky, M. E.; Rahman, Z.; Kilcoyne, A. L. D.; Nakato, A.; Takeichi, Y.; Suga, H.; Miyamoto, C.; Mase, K.;

Chemical Imaging Analysis of Environmental Particles Using the Focused Ion Beam/Scanning Electron Microscopy Technique. Microanalysis Insights into Atmospheric Chemistry of Fly Ash

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Haihan; Grassian, Vicki H.; Saraf, Laxmikant V.

2012-11-08

Airborne fly ash from coal combustion may represent a source of bioavailable iron (Fe) in the open ocean. However, few studies have been made focusing on Fe speciation and distribution in coal fly ash. In this study, chemical imaging of fly ash has been performed using a dual-beam FIB/SEM (focused ion beam/scanning electron microscope) system for a better understanding of how simulated atmospheric processing modify the morphology, chemical compositions and element distributions of individual particles. A novel approach has been applied for cross-sectioning of fly ash specimen with a FIB in order to explore element distribution within the interior ofmore » individual particles. Our results indicate that simulated atmospheric processing causes disintegration of aluminosilicate glass, a dominant material in fly ash particles. Aluminosilicate-phase Fe in the inner core of fly ash particles is more easily mobilized compared with oxide-phase Fe present as surface aggregates on fly ash spheres. Fe release behavior depends strongly on Fe speciation in aerosol particles. The approach for preparation of cross-sectioned specimen described here opens new opportunities for particle microanalysis, particular with respect to inorganic refractive materials like fly ash and mineral dust.« less

Cryo-FIB specimen preparation for use in a cartridge-type cryo-TEM.

PubMed

He, Jie; Hsieh, Chyongere; Wu, Yongping; Schmelzer, Thomas; Wang, Pan; Lin, Ying; Marko, Michael; Sui, Haixin

2017-08-01

Cryo-electron tomography (cryo-ET) is a well-established technique for studying 3D structural details of subcellular macromolecular complexes and organelles in their nearly native context in the cell. A primary limitation of the application of cryo-ET is the accessible specimen thickness, which is less than the diameters of almost all eukaryotic cells. It has been shown that focused ion beam (FIB) milling can be used to prepare thin, distortion-free lamellae of frozen biological material for high-resolution cryo-ET. Commercial cryosystems are available for cryo-FIB specimen preparation, however re-engineering and additional fixtures are often essential for reliable results with a particular cryo-FIB and cryo-transmission electron microscope (cryo-TEM). Here, we describe our optimized protocol and modified instrumentation for cryo-FIB milling to produce thin lamellae and subsequent damage-free cryotransfer of the lamellae into our cartridge-type cryo-TEM. Published by Elsevier Inc.

Matrices pattern using FIB; 'Out-of-the-box' way of thinking.

PubMed

Fleger, Y; Gotlib-Vainshtein, K; Talyosef, Y

2017-03-01

Focused ion beam (FIB) is an extremely valuable tool in nanopatterning and nanofabrication for potentially high-resolution patterning, especially when refers to He ion beam microscopy. The work presented here demonstrates an 'out-of-the-box' method of writing using FIB, which enables creating very large matrices, up to the beam-shift limitation, in short times and with high accuracy unachievable by any other writing technique. The new method allows combining different shapes in nanometric dimensions and high resolutions for wide ranges. © 2017 The Authors Journal of Microscopy © 2017 Royal Microscopical Society.

A new challenge: in-situ investigation of the elusive nanostructures in wet halite and clay using BIB/FIB-cryo-SEM methods

NASA Astrophysics Data System (ADS)

Desbois, G.; Urai, J. L.

2009-04-01

Mudrocks and saltrocks form seals for hydrocarbon accumulations, aquitards and chemical barriers. The sealing capacity is controlled either by the rock microstructure or by chemical interactions between minerals and the permeating fluid. A detailed knowledge about the sealing characteristics is of particular interest in Petroleum Sciences. Other fields of interest are the storage of anthropogenic carbon dioxide and radioactive waste in geologic formations. A key factor to the understanding of sealing by mudstones and saltrocks is the study of their porosity. However, Halite and clay are so fluids sensitive that investigation on dried samples required by traditional methods of investigations (metal injection methods [6],[3]; magnetic susceptibility measurement [4]; SEM imaging of broken surfaces [5] and CT scanner computing [7]) are critical for robust interpretation. In one hand, none of these methods is able to directly describe the in-situ porosity at the pore scale and on the other hand, most of these methods require dried samples in which the natural structure of pores could be damaged due to the desiccation, dehydration and dissolution-recrystallisation of the fabric. SEM imaging is certainly the most direct approach to investigate the porosity but it is generally limited by the poor quality of the mechanically prepared surfaces. This problem is solved by the recent development of ion milling tools (FIB: Focussed Ion Beam or BIB: Broad Ion Beam, which allows producing in-situ high quality polished cross-sections suitable for high resolution pores SEM imaging at nano-scale. More over, new and innovative developments of the cryo-SEM approach in the Geosciences allow investigating samples under wet natural conditions. Thus, we are developing the combination of FIB/BIB-cryo-SEM methods ([1],[2]), which combine in one machine the vitrification of the pore fluids by very rapid cooling, the excavation of the sample by ion milling tool and SEM imaging. By these, we are able to stabilize the in-situ fluids in grain boundaries or pores, preserve the natural structures at nano scale, produce high quality polished cross-sections for high resolution SEM imaging and reconstruct accurately the grain boundary and the pore space networks in 3D by serial cross sectioning. Our first investigations on wet halite and wet clay materials produced unprecedented high quality images of fully preserved fluid-filled pore space as appear in nature. We have thus validated the use of the FIB/BIB-cryo-SEM technology for the in-situ investigations of the elusive structures in wet geomaterials paving the way towards a fuller understanding of how pore geometry can affect physical properties of rocks. [1] Desbois G. And Urai J.L. (submitted). In-situ morphology of meso-porosity in Boom clay (Mol site, Belgium) inferred by the innovative FIB-cryo-SEM method. E-earth. [2] Desbois G., Urai J.L., Burkhardt C., Drury M., Hayles M. and Humbel B. (2008). Cryogenic vitrification and 3D serial sectioning using high resolution cryo-FIB-SEM technology for brine-filled grain boundaries in halite: first results. Geofluids, 8: 60-72 [3] Esteban L., Géraud Y. And Bouchez J.L. (2006). Pore network geometry in low permeability argillites from magnetic fabric data and oriented mercury injections. Geophysical Research Letters, vol. 33, L18311, doi : 10.1029/2006GL026908. [4] Esteban L., Géraud Y. And Bouchez J.L. (2007). Pore network connectivity anisotropy in Jurassic argillite specimens from eastern Paris Basin (France). Physics and Chemistry of the Earth, 32(1) :161-169. [5] Hildenbrand A., Krooss B. M. and Urai J. L. (2005). Relationship between pore structure and fluid transport in argillaceous rocks. Solid Mechanics and Its Applications, IUTAM Symposium on Physicochemical and Electromechanical Interactions in Porous Media, 125 : 231-237, doi : 10.1007/1-4020-3865-8_26. [6] Hildenbrand A. and Urai J.L. (2003) Investigation of the morphology of pore space in mudstones—first results. Marine and Petroleum Geology, 20(10):1185-1200. [7] H. Taud H., Martinez-Angeles R., Parrot J.F., Hernandez-Escobedo L. (2005). Porosity estimation method by X-ray computed tomography. Journal of Petroleum Science and Engineering, (47), 3-4, 30: 209-217

Mapping the Complex Morphology of Cell Interactions with Nanowire Substrates Using FIB-SEM

PubMed Central

Jensen, Mikkel R. B.; Łopacińska, Joanna; Schmidt, Michael S.; Skolimowski, Maciej; Abeille, Fabien; Qvortrup, Klaus; Mølhave, Kristian

2013-01-01

Using high resolution focused ion beam scanning electron microscopy (FIB-SEM) we study the details of cell-nanostructure interactions using serial block face imaging. 3T3 Fibroblast cellular monolayers are cultured on flat glass as a control surface and on two types of nanostructured scaffold substrates made from silicon black (Nanograss) with low- and high nanowire density. After culturing for 72 hours the cells were fixed, heavy metal stained, embedded in resin, and processed with FIB-SEM block face imaging without removing the substrate. The sample preparation procedure, image acquisition and image post-processing were specifically optimised for cellular monolayers cultured on nanostructured substrates. Cells display a wide range of interactions with the nanostructures depending on the surface morphology, but also greatly varying from one cell to another on the same substrate, illustrating a wide phenotypic variability. Depending on the substrate and cell, we observe that cells could for instance: break the nanowires and engulf them, flatten the nanowires or simply reside on top of them. Given the complexity of interactions, we have categorised our observations and created an overview map. The results demonstrate that detailed nanoscale resolution images are required to begin understanding the wide variety of individual cells’ interactions with a structured substrate. The map will provide a framework for light microscopy studies of such interactions indicating what modes of interactions must be considered. PMID:23326412

Three-Dimensional FIB/EBSD Characterization of Irradiated HfAl3-Al Composite

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hua, Zilong; Guillen, Donna Post; Harris, William

2016-09-01

A thermal neutron absorbing material, comprised of 28.4 vol% HfAl3 in an Al matrix, was developed to serve as a conductively cooled thermal neutron filter to enable fast flux materials and fuels testing in a pressurized water reactor. In order to observe the microstructural change of the HfAl3-Al composite due to neutron irradiation, an EBSD-FIB characterization approach is developed and presented in this paper. Using the focused ion beam (FIB), the sample was fabricated to 25µm × 25µm × 20 µm and mounted on the grid. A series of operations were carried out repetitively on the sample top surface tomore » prepare it for scanning electron microscopy (SEM). First, a ~100-nm layer was removed by high voltage FIB milling. Then, several cleaning passes were performed on the newly exposed surface using low voltage FIB milling to improve the SEM image quality. Last, the surface was scanned by Electron Backscattering Diffraction (EBSD) to obtain the two-dimensional image. After 50 to 100 two-dimensional images were collected, the images were stacked to reconstruct a three-dimensional model using DREAM.3D software. Two such reconstructed three-dimensional models were obtained from samples of the original and post-irradiation HfAl3-Al composite respectively, from which the most significant microstructural change caused by neutron irradiation apparently is the size reduction of both HfAl3 and Al grains. The possible reason is the thermal expansion and related thermal strain from the thermal neutron absorption. This technique can be applied to three-dimensional microstructure characterization of irradiated materials.« less

An improved cryo-FIB method for fabrication of frozen hydrated lamella.

PubMed

Zhang, Jianguo; Ji, Gang; Huang, Xiaojun; Xu, Wei; Sun, Fei

2016-05-01

Cryo-electron tomography (cryo-ET) provides great insights into the ultrastructure of cells and tissues in their native state and provides a promising way to study the in situ 3D structures of macromolecular complexes. However, this technique has been limited on the very thin specimen, which is not applicable for most cells and tissues. Besides cryo-sectioning approach, cryo focused ion beam (cryo-FIB) appeared recently to achieve 'artifact-free' thin frozen hydrated lamella via fabrication. Considering that the current cryo-FIB methods need modified holders or cartridges, here, with a "D-shaped" molybdenum grid and a specific shutter system, we developed a simple cryo-FIB approach for thin frozen hydrated lamella fabrication, which fits both standard transmission cryo-electron microscopes with side-entry cryo-holders and state-of-the-art ones with AutoGrids. Our approach will expand the usage of cryo-FIB approach in many labs. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

The Microstructure of RR1000 Nickel-Base Superalloy: The FIB-SEM Dual-Beam Approach

NASA Astrophysics Data System (ADS)

Croxall, S. A.; Hardy, M. C.; Stone, H. J.; Midgley, P. A.

Nickel-base superalloys are aerospace materials that exhibit exceptional mechanical properties and corrosion resistance at very high temperatures. RR1000 is used in discs in gas turbine engines, where temperatures reach in excess of 650°C with high mechanical stresses. Study of the microstructure at the micron and sub-micron level has conventionally been undertaken using scanning electron microscope images, often meaning the underlying 3D microstructure can be inferred only with additional knowledge. Using a dual-beam workstation, we are able to interrogate directly the 3D microstructure using a serial sectioning approach. The 3D data set, typically (10µm)3 in volume, reveals microstructural detail with lateral resolution of circa 8nm and a depth resolution dictated by the slice thickness, typically 50nm. Morphological and volumetric analysis of the 3D reconstruction of RR1000 superalloy reveals microstructural details hitherto unseen.

Multi-scale 3D characterization of long period stacking ordered structure in Mg-Zn-Gd cast alloys.

PubMed

Ishida, Masahiro; Yoshioka, Satoru; Yamamoto, Tomokazu; Yasuda, Kazuhiro; Matsumura, Syo

2014-11-01

Magnesium alloys containing rare earth elements are attractive as lightweight structural materials due to their low density, high-specific strength and recycling efficiency. Mg-Zn-Gd system is one of promising systems because of their high creep-resistant property[1]. It is reported that the coherent precipitation formation of the 14H long period stacking ordered structure (LPSO) in Mg-Zn-Gd system at temperatures higher than 623 K[2,3]. In this study, the 14H LPSO phase formed in Mg-Zn-Gd alloys were investigated by multi-scale characterization with X-ray computer tomography (X-CT), focused ion beam (FIB) tomography and aberration-corrected STEM observation for further understanding of the LPSO formation mechanism.The Mg89.5 Zn4.5 Gd6 alloy ingots were cast using high-frequency induction heating in argon atmosphere. The specimens were aged at 753 K for 24 h in air. The aged specimen were cut and polished mechanically for microstructural analysis. The micrometer resolution X-CT observation was performed by conventional scaner (Bruker SKY- SCAN1172) at 80 kV. The FIB tomography and energy dispersive x-ray spectroscopy (EDS) were carried out by a dual beam FIB-SEM system (Hitachi MI-4000L) with silicon drift detector (SDD) (Oxford X-Max(N)). The electron acceleration voltages were used with 3 kV for SEM observation and 10 kV for EDX spectroscopy. The 3D reconstruction from image series was performed by Avizo Fire 8.0 software (FEI). TEM/STEM observations were also performed by transmission electron microscopes (JEOL JEM 2100, JEM-ARM 200F) at the acceleration voltage of 200 keV.The LPSO phase was observed clearly in SEM image of the Mg89.5Zn4.5Gd6 alloy at 753 K for 2h (Fig.1 (a)). The atomic structure of LPSO phase observed as white gray region of SEM image was also confirmed as 14H LPSO structure by using selected electron diffraction patterns and high-resolution STEM observations. The elemental composition of LPSO phase was determined as Mg97Zn1Gd2 by EDS analyses. The 3D representation of the LPSO phase shown in Fig.1 (b) reveals that the shape of LPSO phase was disk-like. The calculated volume fraction of LPSO was about 20%, which is consistent with estimated value from initial composition. The stacked LPSO disks were distributed along 3D network. It is suggested that this 3D structure is concerned with the distribution of Mg3Gd compounds observed in as-cast specimens.jmicro;63/suppl_1/i25-a/DFU068F1F1DFU068F1Fig. 1.(a) SEM image of the Mg89.5Zn4.5Gd6 alloy aged at 753 K for 2h. (b) 3D representation of the tomographic reconstruction from SEM images. The soiled parts of the 3D volume are 14 H LPSO phase. © The Author 2014. Published by Oxford University Press on behalf of The Japanese Society of Microscopy. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Analytical and Experimental Nanomechanical Approaches to Understanding the Ductile-to-Brittle Transition

NASA Astrophysics Data System (ADS)

Hintsala, Eric Daniel

This dissertation presents progress towards understanding the ductile-to-brittle transition (DBT) using a mixture of nanomechanical experiments and an analytical model. The key concept is dislocation shielding of crack tips, which is occurs due to a dislocation back stress. In order to properly evaluate the role of these interactions, in-situ experiments are ideal by reducing the number of interacting dislocations and allowing direct observation of cracking behavior and the dislocations themselves. First, in-situ transmission electron microscope (TEM) compression experiments of plasma-synthesized silicon nanocubes (NCs) are presented which shows plastic strains greater than 50% in a semi-brittle material. The mechanical properties are discussed and plasticity mechanisms are identified using post-mortem imaging with a combination of dark field and high-resolution imaging. This observations help to develop a back stress model which is used to fit the hardening regime. This represents the first study of its kind where back stresses are used in a discrete manner to match hardening rates. However, the important measurable quantities for evaluating the DBT include fracture toughness values and energetic activation parameters for cracking and plasticity. In order to do this, a new method for doing in-situ fracture experiments is explored. This method is pre-notched three point bending experiments, which were fabricated by focused ion beam (FIB) milling. Two different materials are evaluated: a model ductile material, Nitronic 50, an austenitic steel alloy, and a model brittle material, silicon. These experiments are performed in-situ scanning electron microscope (SEM) and TEM and explore different aspects including electron backscatter diffraction (EBSD) to track deformation in SEM scale experiments, pre-notching using a converged TEM beam to produce sharper notches better replicating natural cracks, etching procedures to reduce residual FIB damage and elevated temperature experiments. Lastly, an analytical method to predict DBTs is presented which can account for effects of strain rate, temperature and impurity presence. The model is tested by pre-existing data on macroscopic compact tension specimens of single crystal Fe-3%Si. Next, application of the model to nano/micro scale fracture toughness experiments is explored and the large number of confounding variables is discussed in detail. A first attempt at fitting is also presented.

Reconstruction of the 3-D Shape and Crystal Preferred Orientation of Olivine: A Combined X-ray µ-CT and EBSD-SEM approach

NASA Astrophysics Data System (ADS)

Kahl, Wolf-Achim; Hidas, Károly; Dilissen, Nicole; Garrido, Carlos J.; López-Sánchez Vizcaíno, Vicente; Jesús Román-Alpiste, Manuel

2017-04-01

The complete reconstruction of the microstructure of rocks requires, among others, a full description of the shape preferred orientation (SPO) and crystal preferred orientation (CPO) of the constituent mineral phases. New advances in instrumental analyses, particularly electron backscatter diffraction (EBSD) coupled to focused ion beam-scanning electron microscope (FIB-SEM), allows a complete characterization of SPO and CPO in rocks at the micron scale [1-2]. Unfortunately, the large grain size of many crystalline rocks, such as peridotite, prevents a representative characterization of the CPO and SPO of their constituent minerals by this technique. Here, we present a new approach combining X-ray micro computed tomography (µ-CT) and EBSD to reconstruct the geographically oriented, 3-D SPO and CPO of cm- to mm-sized olivine crystals in two contrasting fabric types of chlorite harzburgites (Almírez ultramafic massif, SE Spain). The semi-destructive sample treatment involves drilling of geographically oriented micro drills in the field and preparation of oriented thin sections from µ-CT scanned cores. This allows for establishing the link among geological structures, macrostructure, fabric, and 3-D SPO-CPO at the thin section scale. Based on EBSD analyses, different CPO groups of olivine crystals can be discriminated in the thin sections and allocated to 3-D SPO in the µ-CT volume data. This approach overcomes the limitations of both methods (i.e., no crystal orientation data in µ-CT and no spatial information in EBSD), hence 3-D orientation of the crystallographic axes of olivines from different orientation groups could be correlated with the crystal shapes of olivine grains. This combined µ-CT and EBSD technique enables the correlation of both SPO and CPO and representative grain size, and is capable to characterize the 3-D microstructure of olivine-bearing rocks at the hand specimen scale. REFERENCES 1. Zaefferer, S., Wright, S.I., Raabe, D., 2008. Three-Dimensional orientation microscopy in a focused ion beam-scanning electron microscope: A new dimension of microstructure characterization. Metallurgical and Materials Transactions A 39, 374-389. 2. Burnett, T.L., Kelley, R., Winiarski, B., Contreras, L., Daly, M., Gholinia, A., Burke, M.G., Withers, P.J., 2016. Large volume serial section tomography by Xe Plasma FIB dual beam microscopy. Ultramicroscopy 161, 119-129.

A Novel SPM Probe with MOS Transistor and Nano Tip for Surface Electric Properties

NASA Astrophysics Data System (ADS)

Lee, Sang H.; Lim, Geunbae; Moon, Wonkyu

2007-03-01

In this paper, the novel SPM (Scanning Probe Microscope) probe with the planar MOS (Metal-Oxide-Semiconductor) transistor and the FIB (Focused Ion Beam) nano tip is fabricated for the surface electric properties. Since the MOS transistor has high working frequency, the device can overcome the speed limitation of EFM (Electrostatic Force Microscope) system. The sensitivity is also high, and no bulky device such as lock-in-amplifier is required. Moreover, the nano tip with nanometer scale tip radius is fabricated with FIB system, and the resolution can be improved. Therefore, the probe can rapidly detect small localized electric properties with high sensitivity and high resolution. The MOS transistor is fabricated with the common semiconductor process, and the nano tip is grown by the FIB system. The planar structure of the MOS transistor makes the fabrication process easier, which is the advantage on the commercial production. Various electric signals are applied using the function generator, and the measured data represent the well-established electric properties of the device. It shows the promising aspect of the local surface electric property detection with high sensitivity and high resolution.

Direct observation of dopant distribution in GaAs compound semiconductors using phase-shifting electron holography and Lorentz microscopy.

PubMed

Sasaki, Hirokazu; Otomo, Shinya; Minato, Ryuichiro; Yamamoto, Kazuo; Hirayama, Tsukasa

2014-06-01

Phase-shifting electron holography and Lorentz microscopy were used to map dopant distributions in GaAs compound semiconductors with step-like dopant concentration. Transmission electron microscope specimens were prepared using a triple beam focused ion beam (FIB) system, which combines a Ga ion beam, a scanning electron microscope, and an Ar ion beam to remove the FIB damaged layers. The p-n junctions were clearly observed in both under-focused and over-focused Lorentz microscopy images. A phase image was obtained by using a phase-shifting reconstruction method to simultaneously achieve high sensitivity and high spatial resolution. Differences in dopant concentrations between 1 × 10(19) cm(-3) and 1 × 10(18) cm(-3) regions were clearly observed by using phase-shifting electron holography. We also interpreted phase profiles quantitatively by considering inactive layers induced by ion implantation during the FIB process. The thickness of an inactive layer at different dopant concentration area can be measured from the phase image. © The Author 2014. Published by Oxford University Press on behalf of The Japanese Society of Microscopy. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Preparation of MgB2 superconducting microbridges by focused ion beam direct milling

NASA Astrophysics Data System (ADS)

Zhang, Xuena; Li, Yanli; Xu, Zhuang; Kong, Xiangdong; Han, Li

2017-01-01

MgB2 superconducting microbridges were prepared by focused ion beam (FIB) direct milling on MgB2 films. The surface topography of the microbridges were observed using SEM and AFM and the superconductivity was measured in this paper. Lots of cracks and holes were found near the milled area. And the superconducting transition temperature was decreased a lot and the bridges prepared were not superconducting due to ion damage after milled with large dose. Through these works, we explored the effect regular of FIB milling and experimental parameters on the performance of microbridges.

A flexible method for the preparation of thin film samples for in situ TEM characterization combining shadow-FIB milling and electron-beam-assisted etching.

PubMed

Liebig, J P; Göken, M; Richter, G; Mačković, M; Przybilla, T; Spiecker, E; Pierron, O N; Merle, B

2016-12-01

A new method for the preparation of freestanding thin film samples for mechanical testing in transmission electron microscopes is presented. It is based on a combination of focused ion beam (FIB) milling and electron-beam-assisted etching with xenon difluoride (XeF 2 ) precursor gas. The use of the FIB allows for the target preparation of microstructural defects and enables well-defined sample geometries which can be easily adapted in order to meet the requirements of various testing setups. In contrast to existing FIB-based preparation approaches, the area of interest is never exposed to ion beam irradiation which preserves a pristine microstructure. The method can be applied to a wide range of thin film material systems compatible with XeF 2 etching. Its feasibility is demonstrated for gold and alloyed copper thin films and its practical application is discussed. Copyright © 2016 Elsevier B.V. All rights reserved.

Mapping Strain Gradients in the FIB-Structured InGaN/GaN Multilayered Films with 3D X-ray Microbeam

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barabash, Rozaliya; Gao, Yanfei; Ice, Gene E

2010-01-01

This research presents a combined experimental-modeling study of lattice rotations and deviatoric strain gradients induced by focused-ion beam (FIB) milling in nitride heterostructures. 3D X-ray polychromatic microdiffraction (PXM) is used to map the local lattice orientation distribution in FIB-structured areas. Results are discussed in connection with microphotoluminescence ({mu}-PL), fluorescent analysis, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) data. It is demonstrated that FIB-milling causes both direct and indirect damage to the InGaN/GaN layers. In films subjected to direct ion beam impact, a narrow amorphidized top layer is formed. Near the milling area, FIB-induced stress relaxation and formation ofmore » complicated 3D strain fields are observed. The resulting lattice orientation changes are found to correlate with a decrease and/or loss of PL intensity, and agree well with finite element simulations of the three-dimensional strain fields near the relaxed trenches. Experimentally, it is found that the lattice surface normal has an in-plane rotation, which only appears in simulations when the GaN-substrate lattice mismatch annihilates the InGaN-substrate mismatch. This behavior further supports the notion that the film/substrate interface is incoherent.« less

Mapping strain gradients in the FIB-structured InGaN/GaN multilayered films with 3D x-ray microbeam.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barabash, R. I.; Gao, Y. F.; Ice, G. E.

2010-11-25

This research presents a combined experimental-modeling study of lattice rotations and deviatoric strain gradients induced by focused-ion beam (FIB) milling in nitride heterostructures. 3D X-ray polychromatic microdiffraction (PXM) is used to map the local lattice orientation distribution in FIB-structured areas. Results are discussed in connection with microphotoluminescence ({mu}-PL), fluorescent analysis, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) data. It is demonstrated that FIB-milling causes both direct and indirect damage to the InGaN/GaN layers. In films subjected to direct ion beam impact, a narrow amorphidized top layer is formed. Near the milling area, FIB-induced stress relaxation and formation ofmore » complicated 3D strain fields are observed. The resulting lattice orientation changes are found to correlate with a decrease and/or loss of PL intensity, and agree well with finite element simulations of the three-dimensional strain fields near the relaxed trenches. Experimentally, it is found that the lattice surface normal has an in-plane rotation, which only appears in simulations when the GaN-substrate lattice mismatch annihilates the InGaN-substrate mismatch. This behavior further supports the notion that the film/substrate interface is incoherent.« less

Precession electron diffraction for SiC grain boundary characterization in unirradiated TRISO fuel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lillo, T. M.; van Rooyen, I. J.; Wu, Y. Q.

Precession electron diffraction (PED), a transmission electron microscopy-based technique, has been evaluated for the suitability for evaluating grain boundary character in the SiC layer of tristructural isotropic (TRISO) fuel. Although the ultimate goal is to determine the grain boundary characteristics of fission product containing grain boundaries of neutron irradiated SiC, our work reports the effect of transmission electron microscope (TEM) lamella thickness on quality of data and establishes a baseline comparison on grain boundary characteristics determined previously using a conventional EBSD scanning electron microscope (SEM) based technique. In general, it was determined that the lamella thickness produced using the standardmore » FIB fabrication process, is sufficient to provide reliable PED measurements with thicker lamellae (~120 nm) produce higher quality orientation data. Analysis of grain boundary character from the TEM-based PED data showed a much lower fraction of low angle grain boundaries compared to SEM-based EBSD data from the SiC layer of the same TRISO-coated particle as well as a SiC layer deposited at a slightly lower temperature. The fractions of high angle and CSL-related grain boundaries determined by PED are similar to those found using SEM-based EBSD. Since the grain size of the SiC layer of TRSIO fuel can be as small as 250 nm [12], depending on the fabrication parameters, and grain boundary fission product precipitates can be nano-sized, the TEM-based PED orientation data collection method is preferred to determine an accurate representation of the relative fractions of low angle, high angle and CSL-related grain boundaries. It was concluded that although the resolution of the PED data is better by more than an order of magnitude, data acquisition times may be significantly longer or the number of areas analyzed significantly larger than the SEM-based method to obtain a statistically relevant distribution. Also, grain size could be accurately determined but significantly larger analysis areas than those used in this study would be required.« less

Precession electron diffraction for SiC grain boundary characterization in unirradiated TRISO fuel

DOE PAGES

Lillo, T. M.; van Rooyen, I. J.; Wu, Y. Q.

2016-06-16

Precession electron diffraction (PED), a transmission electron microscopy-based technique, has been evaluated for the suitability for evaluating grain boundary character in the SiC layer of tristructural isotropic (TRISO) fuel. Although the ultimate goal is to determine the grain boundary characteristics of fission product containing grain boundaries of neutron irradiated SiC, our work reports the effect of transmission electron microscope (TEM) lamella thickness on quality of data and establishes a baseline comparison on grain boundary characteristics determined previously using a conventional EBSD scanning electron microscope (SEM) based technique. In general, it was determined that the lamella thickness produced using the standardmore » FIB fabrication process, is sufficient to provide reliable PED measurements with thicker lamellae (~120 nm) produce higher quality orientation data. Analysis of grain boundary character from the TEM-based PED data showed a much lower fraction of low angle grain boundaries compared to SEM-based EBSD data from the SiC layer of the same TRISO-coated particle as well as a SiC layer deposited at a slightly lower temperature. The fractions of high angle and CSL-related grain boundaries determined by PED are similar to those found using SEM-based EBSD. Since the grain size of the SiC layer of TRSIO fuel can be as small as 250 nm [12], depending on the fabrication parameters, and grain boundary fission product precipitates can be nano-sized, the TEM-based PED orientation data collection method is preferred to determine an accurate representation of the relative fractions of low angle, high angle and CSL-related grain boundaries. It was concluded that although the resolution of the PED data is better by more than an order of magnitude, data acquisition times may be significantly longer or the number of areas analyzed significantly larger than the SEM-based method to obtain a statistically relevant distribution. Also, grain size could be accurately determined but significantly larger analysis areas than those used in this study would be required.« less

Compositional and Microstructural Evolution of Olivine During Pulsed Laser Irradiation: Insights Based on a FIB/Field-Emission TEM Study

NASA Technical Reports Server (NTRS)

Christoffersen, R.; Loeffler, M. J.; Dukes, C. A.; Baragiola, R. A.

2015-01-01

Introduction: The use of pulsed laser irradiation to simulate the short duration, high-energy conditions characteristic of micrometeorite impacts is now an established approach in experimental space weathering studies. The laser generates both melt and vapor deposits that contain nanophase metallic Fe (npFe(sup 0)) grains with size distributions and optical properties similar to those in natural impact-generated melt and vapor deposits. There remains uncertainty, however, about how well lasers simulate the mechanical work and internal (thermal) energy partitioning that occurs in actual impacts. We are currently engaged in making a direct comparison between the products of laser irradiation and experimental/natural hypervelocity impacts. An initial step reported here is to use analytical TEM is to attain a better understanding of how the microstructure and composition of laser deposits evolve over multiple cycles of pulsed laser irradiation. Experimental Methods: We irradiated pressed-powder pellets of San Carlos olivine (Fo(sub 90)) with up to 99 rastered pulses of a GAM ArF excimer laser. The irradiated surface of the sample were characterized by SEM imaging and areas were selected for FIB cross sectioning for TEM study using an FEI Quanta dual-beam electron/focused ion beam instrument. FIB sections were characterized using a JEOL2500SE analytical field-emission scanning transmission electron microscope (FE-STEM) optimized for quantitative element mapping at less than 10 nm spatial resolutions. Results: In the SEM the 99 pulse pressed pellet sample shows a complex, inhomogeneous, distribution of laser-generated material, largely concentrated in narrow gaps and larger depressions between grains. Local concentrations of npFe0 spherules 0.1 to 1 micrometers in size are visible within these deposits in SEM back-scatter images. Fig. 1 shows bright-field STEM images of a FIB cross-section of a one of these deposits that continuously covers the top and sloping side of an olivine grain. The deposit has 3 microstructurally distinct sub-layers composed of silicate glass with varying modal fractions and size distributions of npFe( sup 0) spherules, along with nanocrystalline silicate material. A relatively thin (50-300 nm) topmost surface layer has a high-concentration of npFe0 spherules 5-20 nm in size. Element mapping shows the layer to be enriched in Fe by a factor of 2.5 relative to the olivine substrate, with Mg and Si depleted by 20% and 10% respectively. This is compositionally complementary to the underlying, middle layer of the deposit that is depleted in Fe, enriched in Mg and has a much lower npFe0 concentration. A third layer of nanocrystalline olivine occurs at the substrate interface. Discussion: The FE-STEM results suggest the topmost layer is a vapor deposit, underlain by a thicker microstructurally complex melt-generated layer. The compositional relations suggest the melt layer was partially vaporized, preferentially losing more volatile elements (e.g., Fe). The vaporized material re-condensed to form the thin, npFe(sup 0)-rich surface deposit during or immediately after the scan cycle. Nanocrystalline olivine that grew within the melt layer as it formed and cooled is similar in volume and microstructure to what we have observed in the impact melt lining of a micrometeorite impact crater in olivine. This suggest the time-temperature relations attained in the laser sample may not be too different from a micrometeorite impact. Our TEM observations, however, do not show evidence for the same level of mechanical dam-age (e.g., fracturing) seen around the natural micrometeorite crater.

Three-Dimensional Analysis of Peeled Internal Limiting Membrane Using Focused Ion Beam/Scanning Electron Microscopy

PubMed Central

Murata, Kazuhisa; Hayashi, Ken; Nakamura, Kei-ichiro

2018-01-01

Purpose To reevaluate the effect of internal limiting membrane peeling during vitrectomy on the Müller cell damage, we examined the ultrastructure of the internal limiting membrane by using focused ion beam/scanning electron microscopy (FIB/SEM). Methods A total of 12 internal limiting membranes obtained during surgery in both the macular hole and the idiopathic epiretinal membrane groups were processed for observation by FIB/SEM. Three-dimensional structures of the internal limiting membrane were analyzed. Results The number of cell fragments in the macular hole group was 5.07 ± 1.03 per unit area of internal limiting membrane (100 μm2). The total volume of cell fragments was 3.54 ± 1.24 μm3/100 μm2. In contrast, the number of cell fragments in the epiretinal membrane group was 12.85 ± 3.45/100 μm2, and the total volume of cell fragments was 10.45 ± 2.77 μm3/100 μm2. Data for both values were significantly higher than those observed in the macular hole group (P = 0.0024 and P = 0.0022, respectively, Mann-Whitney U test). No statistical difference was found for the mean volume of the cell fragment between the two groups. Conclusions All of the internal limiting membrane examined in this study showed cell fragments on the retinal surface of the internal limiting membrane. As compared with macular hole, epiretinal membrane exhibited a higher number and total volume of cell fragments, indicating that internal limiting membrane peeling for epiretinal membrane might have a higher risk of causing inner retinal damage. Translational Relevance FIB/SEM was a useful tool for three-dimensional quantitative analysis of the internal limiting membrane. PMID:29423341

Characterization of laser induced damage of HR coatings with picosecond pulses

NASA Astrophysics Data System (ADS)

Li, Cheng; Zhao, Yuan'an; Cui, Yun; Wang, Yueliang; Peng, Xiaocong; Shan, Chong; Zhu, Meiping; Wang, Jianguo; Shao, Jianda

2017-11-01

The effect of protective layer on the picosecond laser-induced damage behaviors of HfO2/SiO2 high-reflective (HR) coatings are explored. Two kinds of 1064nm HR coatings with and without protective layer are deposited by electron beam evaporation. Laser-induced damage tests are conducted with 1064nm, 30ps S-polarized and P-polarized pulses with different angle of incidence (AOI) to make the electric fields intensity in the HR coatings discrepantly. Damage morphology and cross section of damage sites were characterized by scanning electron microscope (SEM) and focused ion beam (FIB), respectively. It is found that SiO2 protective layer have a certain degree of improvement on laser induced damage threshold (LIDT) for every AOIs. The onset damage initiated very near to the Max peak of e-field, after which forms ripple-like pits. The damage morphology presents as layer delamination at high fluence. The Laser damage resistance is correspond with the maximum E-intensity in the coating stacks.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Zhao; Chen-Wiegart, Yu-chen K.; Wang, Jun

Three-phase three-dimensional (3D) microstructural reconstructions of lithium-ion battery electrodes are critical input for 3D simulations of electrode lithiation/delithiation, which provide a detailed understanding of battery operation. In this report, 3D images of a LiCoO 2electrode are achieved using focused ion beam-scanning electron microscopy (FIB-SEM), with clear contrast among the three phases: LiCoO 2particles, carbonaceous phases (carbon and binder) and the electrolyte space. The good contrast was achieved by utilizing an improved FIB-SEM sample preparation method that combined infiltration of the electrolyte space with a low-viscosity silicone resin and triple ion-beam polishing. Morphological parameters quantified include phase volume fraction, surface area,more » feature size distribution, connectivity, and tortuosity. Electrolyte tortuosity was determined using two different geometric calculations that were in good agreement. In conclusion, the electrolyte tortuosity distribution versus position within the electrode was found to be highly inhomogeneous; this will lead to inhomogeneous electrode lithiation/delithiation at high C-rates that could potentially cause battery degradation.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Zhao; Chen-Wiegart, Yu-chen K.; Wang, Jun

Abstract Three-phase three-dimensional (3D) microstructural reconstructions of lithium-ion battery electrodes are critical input for 3D simulations of electrode lithiation/delithiation, which provide a detailed understanding of battery operation. In this report, 3D images of a LiCoO 2electrode are achieved using focused ion beam-scanning electron microscopy (FIB-SEM), with clear contrast among the three phases: LiCoO 2particles, carbonaceous phases (carbon and binder) and the electrolyte space. The good contrast was achieved by utilizing an improved FIB-SEM sample preparation method that combined infiltration of the electrolyte space with a low-viscosity silicone resin and triple ion-beam polishing. Morphological parameters quantified include phase volume fraction, surfacemore » area, feature size distribution, connectivity, and tortuosity. Electrolyte tortuosity was determined using two different geometric calculations that were in good agreement. The electrolyte tortuosity distribution versus position within the electrode was found to be highly inhomogeneous; this will lead to inhomogeneous electrode lithiation/delithiation at high C-rates that could potentially cause battery degradation.« less

Initial formation of calcite crystals in the thin prismatic layer with the periostracum of Pinctada fucata.

PubMed

Suzuki, Michio; Nakayama, Seiji; Nagasawa, Hiromichi; Kogure, Toshihiro

2013-02-01

Although the formation mechanism of calcite crystals in the prismatic layer has been studied well in many previous works, the initial state of calcite formation has not been observed in detail using electron microscopes. In this study, we report that the soft prismatic layer with transparent color (the thin prismatic layer) in the tip of the fresh shell of Pinctada fucata was picked up to observe the early calcification phase. A scanning electron microscope (SEM) image showed that the growth tip of the thin prismatic layer was covered by the periostracum, which was also where the initial formation of calcite crystals began. A cross-section containing the thin calcite crystals in the thin prismatic layer with the periostracum was made using a focused ion beam (FIB) system. In a transmission electron microscope (TEM) observation, the thin calcite crystal (thickness is about 1μm) on the periostracum was found to be a single crystal with the c-axis oriented perpendicular to the shell surface. On the other hand, many aggregated small particles consisting of bassanite crystals were observed in the periostracum suggesting the possibility that not only organic sulfate but also inorganic sulfates exist in the prismatic layer. These discoveries in the early calcification phase of the thin prismatic layer may help to clarify the mechanism of regulating the nucleation and orientation of the calcite crystal in the shell. Copyright © 2012 Elsevier Ltd. All rights reserved.

Thinning of Large Biological Cells for Cryo-TEM Characterization by Cryo-FIB Milling

PubMed Central

Strunk, Korrinn M.; Ke, Danxia; Gray, Jennifer L.; Zhang, Peijun

2013-01-01

SUMMARY Focused ion beam milling at cryogenic temperatures (cryo-FIB) is a valuable tool that can be used to thin vitreous biological specimens for subsequent imaging and analysis in a cryo-transmission electron microscope (cryo-TEM) in their frozen-hydrated state. This technique offers the potential benefit of eliminating the mechanical artifacts that are typically found with cryo-ultramicrotomy. However, due to the additional complexity in transferring samples in and out of the FIB, contamination and devitrification of the amorphous ice is commonly encountered. In order to address these problems, we have designed a new sample cryo-shuttle that specifically accepts Polara TEM cartridges directly in order to simplify the transfer process between the FIB and TEM. We used the quality of the ice in the sample as an indicator to test various parameters used the process, and demonstrated with successful milling of large mammalian cells. By comparing the results from larger HeLa cells to those from E. coli cells, we discuss some of the artifacts and challenges we have encountered using this technique. PMID:22906009

Measuring topographies from conventional SEM acquisitions.

PubMed

Shi, Qiwei; Roux, Stéphane; Latourte, Félix; Hild, François; Loisnard, Dominique; Brynaert, Nicolas

2018-04-27

The present study extends the stereoscopic imaging principle for estimating the surface topography to two orientations, namely, normal to the electron beam axis and inclined at 70° as suited for EBSD analyses. In spite of the large angle difference, it is shown that the topography can be accurately determined using regularized global Digital Image Correlation. The surface topography is compared to another estimate issued from a 3D FIB-SEM procedure where the sample surface is first covered by a Pt layer, and its initial topography is progressively revealed from successive FIB-milling. These two methods are successfully compared on a 6% strained steel specimen in an in situ mechanical test. This analysis is supplemented by a third approach estimating the change of topography from crystal rotations as measured from successive EBSD images. This last technique ignores plastic deformation, and thus only holds in an elastic regime. For the studied example, despite the large plastic flow, it is shown that crystal rotation already accounts for a significant part of the deformation-induced topography. Copyright © 2018 Elsevier B.V. All rights reserved.

Seeing Below the Drop: Direct Nano-to-microscale Imaging of Complex Interfaces involving Solid, Liquid, and Gas Phases

NASA Astrophysics Data System (ADS)

Rykaczewski, Konrad; Landin, Trevan; Walker, Marlon L.; Scott, John Henry J.; Varanasi, Kripa K.

2012-11-01

Nanostructured surfaces with special wetting properties have the potential to transform number of industries, including power generation, water desalination, gas and oil production, and microelectronics thermal management. Predicting the wetting properties of these surfaces requires detailed knowledge of the geometry and the composition of the contact volume linking the droplet to the underlying substrate. Surprisingly, a general nano-to-microscale method for direct imaging of such interfaces has previously not been developed. Here we introduce a three dimensional imaging method which resolves this one-hundred-year-old metrology gap in wetting research. Specifically, we demonstrate direct nano-to-microscale imaging of complex fluidic interfaces using cryofixation in combination with cryo-FIB/SEM. We show that application of this method yields previously unattainable quantitative information about the interfacial geometry of water condensed on silicon nanowire forests with hydrophilic and hydrophobic surface termination in the presence or absence of an intermediate water repelling oil. We also discuss imaging artifacts and the advantages of secondary and backscatter electron imaging, Energy Dispersive Spectrometry (EDS), and three dimensional FIB/SEM tomography.

Three-dimensional characterization of ODS ferritic steel using by FIB-SEM serial sectioning method.

PubMed

Endo, T; Sugino, Y; Ohono, N; Ukai, S; Miyazaki, N; Wang, Y; Ohnuki, S

2014-11-01

Considerable attention has been paid to the research of the electron tomography due to determine the three-dimensional (3D) structure of materials [1]. One of the electron tomography techniques, focused ion beam/scanning electron microscopy (FIB-SEM) imaging has advantages of high resolutions (10 nm), large area observation (μm order) and simultaneous energy dispersive x- ray microanalysis (EDS)/ electron backscatter diffraction (EBSD) analysis. The purpose of this study, three-dimensional EBSD analysis of ODS ferritic steel which carried out cold work using FIB-SEM equipment was conducted, and it aimed at analyzing the microstructure obtained there. The zone annealing tests were conducted for ferritic steel [2,3], which were produced through mechanical alloying and hot-extrusion. After zone annealing, specimens were mechanically polished with #400∼4000 emery paper, 1 µm diamond paste and alumina colloidal silica. The serial sectioning and the 3D-electron backscattering diffraction (3D-EBSD) analysis were carried out. We made the micro pillar (30 x 30 x 15 µm). The EBSD measurements were carried out in each layer after serial sectioning at a step size and milling depth was 80 nm with 30 slices. After EBSD analysis, the series of cross-sectional images were aligned according to arbitrarily specified areas and then stacked up to form a volume. Consequently, we obtained the 3D-IPF maps for ODS ferritic steel. In this specimen, the {111} and {001} grains are layered by turns. In addition, the volume fraction value of both plane are similar. The aspect ratio increases with specimen depth. The 3D-EBSD mapping is useful to analysis of the bulk material since this method obtain many microstructure information, such a shape, volume and orientation of the crystal, grain boundary. © The Author 2014. Published by Oxford University Press on behalf of The Japanese Society of Microscopy. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Microstructural characterization of the cycling behavior of electrodeposited manganese oxide supercapacitors using 3D electron tomography

NASA Astrophysics Data System (ADS)

Dalili, N.; Clark, M. P.; Davari, E.; Ivey, D. G.

2016-10-01

Manganese oxide has been investigated extensively as an electrochemical capacitor or supercapacitor electrode material. Manganese oxide is inexpensive to fabricate and exhibits relatively high capacitance values, i.e., in excess of 200 F g-1 in many cases; the actual value depends very much on the fabrication method and test conditions. The cycling behavior of Mn oxide, fabricated using anodic electrodeposition, is investigated using slice and view techniques, via a dual scanning electron microscope (SEM) and focused ion beam (FIB) instrument to generate three-dimensional (3D) images, coupled with electrochemical characterization. The initial as-fabricated electrode has a rod-like appearance, with a fine-scale, sheet-like morphology within the rods. The rod-like structure remains after cycling, but there are significant morphological changes. These include partial dissolution of Mn oxide followed by redeposition of Mn oxide in regions close to the substrate. The redeposited material has a finer morphology than the original as-fabricated Mn oxide. The Mn oxide coverage is also better near the substrate. These effects result in an increase in the specific capacitance.

Dopant mapping in thin FIB prepared silicon samples by Off-Axis Electron Holography.

PubMed

Pantzer, Adi; Vakahy, Atsmon; Eliyahou, Zohar; Levi, George; Horvitz, Dror; Kohn, Amit

2014-03-01

Modern semiconductor devices function due to accurate dopant distribution. Off-Axis Electron Holography (OAEH) in the transmission electron microscope (TEM) can map quantitatively the electrostatic potential in semiconductors with high spatial resolution. For the microelectronics industry, ongoing reduction of device dimensions, 3D device geometry, and failure analysis of specific devices require preparation of thin TEM samples, under 70 nm thick, by focused ion beam (FIB). Such thicknesses, which are considerably thinner than the values reported to date in the literature, are challenging due to FIB induced damage and surface depletion effects. Here, we report on preparation of TEM samples of silicon PN junctions in the FIB completed by low-energy (5 keV) ion milling, which reduced amorphization of the silicon to 10nm thick. Additional perpendicular FIB sectioning enabled a direct measurement of the TEM sample thickness in order to determine accurately the crystalline thickness of the sample. Consequently, we find that the low-energy milling also resulted in a negligible thickness of electrically inactive regions, approximately 4nm thick. The influence of TEM sample thickness, FIB induced damage and doping concentrations on the accuracy of the OAEH measurements were examined by comparison to secondary ion mass spectrometry measurements as well as to 1D and 3D simulations of the electrostatic potentials. We conclude that for TEM samples down to 100 nm thick, OAEH measurements of Si-based PN junctions, for the doping levels examined here, resulted in quantitative mapping of potential variations, within ~0.1 V. For thinner TEM samples, down to 20 nm thick, mapping of potential variations is qualitative, due to a reduced accuracy of ~0.3 V. This article is dedicated to the memory of Zohar Eliyahou. Copyright © 2014 Elsevier B.V. All rights reserved.

Nitrogen Gas Field Ion Source (GFIS) Focused Ion Beam (FIB) Secondary Electron Imaging: A First Look.

PubMed

Schmidt, Marek E; Yasaka, Anto; Akabori, Masashi; Mizuta, Hiroshi

2017-08-01

The recent technological advance of the gas field ion source (GFIS) and its successful integration into systems has renewed the interest in the focused ion beam (FIB) technology. Due to the atomically small source size and the use of light ions, the limitations of the liquid metal ion source are solved as device dimensions are pushed further towards the single-digit nanometer size. Helium and neon ions are the most widely used, but a large portfolio of available ion species is desirable, to allow a wide range of applications. Among argon and hydrogen, $${\\rm N}_{2}^{{\\plus}} $$ ions offer unique characteristics due to their covalent bond and their use as dopant for various carbon-based materials including diamond. Here, we provide a first look at the $${\\rm N}_{2}^{{\\plus}} $$ GFIS-FIB enabled imaging of a large selection of microscopic structures, including gold on carbon test specimen, thin metal films on insulator and nanostructured carbon-based devices, which are among the most actively researched materials in the field of nanoelectronics. The results are compared with images acquired by He+ ions, and we show that $${\\rm N}_{2}^{{\\plus}} $$ GFIS-FIB can offer improved material contrast even at very low imaging dose and is more sensitive to the surface roughness.

Thermal etching of silver: Influence of rolling defects

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ollivier, M., E-mail: o.maelig@imperial.ac.uk

2016-08-15

Silver is well known to be thermally etched in an oxygen-rich atmosphere and has been extensively studied in the laboratory to understand thermal etching and to limit its effect when this material is used as a catalyst. Yet, in many industrial applications the surface of rolled silver sheets is used without particular surface preparation. Here, it is shown by combining FIB-tomography, FIB-SIMS and analytical SEM that the kinetics of thermal etch pitting are significantly faster on rolled Ag surfaces than on polished surfaces. This occurs due to range of interacting phenomena including (i) the reaction of subsurface carbon-contamination with dissolvedmore » oxygen to form pores that grow to intersect the surface, (ii) surface reconstruction around corrosion pits and surface scratches, and (iii) sublimation at low pressure and high temperature. A method to identify subsurface pores is developed to show that the pores have (111) and (100) internal facets and may be filled with a gas coming from the chemical reaction of oxygen and carbon contamination. - Highlights: Thermal etching of industrial silver sheets vs. polished silver sheets Effect of annealing atmosphere on the thermal etching of silver: surface and subsurface characterization Link between etch pitting and defects induced by rolling. FIB-tomography coupled with EBSD for determining crystal planes of the facets of subsurface pores. FIB-SIMS characterization to probe the gas confined inside subsurface pores.« less

Multi-scale structural analysis of gas diffusion layers

NASA Astrophysics Data System (ADS)

Göbel, Martin; Godehardt, Michael; Schladitz, Katja

2017-07-01

The macroscopic properties of materials are strongly determined by their micro structure. Here, transport properties of gas diffusion layers (GDL) for fuel cells are considered. In order to simulate flow and thermal properties, detailed micro structural information is essential. 3D images obtained by high-resolution computed tomography using synchrotron radiation and scanning electron microscopy (SEM) combined with focused ion beam (FIB) serial slicing were used. A recent method for reconstruction of porous structures from FIB-SEM images and sophisticated morphological image transformations were applied to segment the solid structural components. The essential algorithmic steps for segmenting the different components in the tomographic data-sets are described and discussed. In this paper, two types of GDL, based on a non-woven substrate layer and a paper substrate layer were considered, respectively. More than three components are separated within the synchrotron radiation computed tomography data. That is, fiber system, polytetrafluoroethylene (PTFE) binder/impregnation, micro porous layer (MPL), inclusions within the latter, and pore space are segmented. The usage of the thus derived 3D structure data in different simulation applications can be demonstrated. Simulations of macroscopic properties such as thermal conductivity, depending on the flooding state of the GDL are possible.

Zebrafish skeleton development: High resolution micro-CT and FIB-SEM block surface serial imaging for phenotype identification

PubMed Central

Silvent, Jeremie; Akiva, Anat; Brumfeld, Vlad; Reznikov, Natalie; Rechav, Katya; Yaniv, Karina; Addadi, Lia; Weiner, Steve

2017-01-01

Although bone is one of the most studied living materials, many questions about the manner in which bones form remain unresolved, including fine details of the skeletal structure during development. In this study, we monitored skeleton development of zebrafish larvae, using calcein fluorescence, high-resolution micro-CT 3D images and FIB-SEM in the block surface serial imaging mode. We compared calcein staining of the skeletons of the wild type and nacre mutants, which are transparent zebrafish, with micro-CT for the first 30 days post fertilization embryos, and identified significant differences. We quantified the bone volumes and mineral contents of bones, including otoliths, during development, and showed that such developmental differences, including otolith development, could be helpful in identifying phenotypes. In addition, high-resolution imaging revealed the presence of mineralized aggregates in the notochord, before the formation of the first bone in the axial skeleton. These structures might play a role in the storage of the mineral. Our results highlight the potential of these high-resolution 3D approaches to characterize the zebrafish skeleton, which in turn could prove invaluable information for better understanding the development and the characterization of skeletal phenotypes. PMID:29220379

Characterization and extraction of the synaptic apposition surface for synaptic geometry analysis

PubMed Central

Morales, Juan; Rodríguez, Angel; Rodríguez, José-Rodrigo; DeFelipe, Javier; Merchán-Pérez, Angel

2013-01-01

Geometrical features of chemical synapses are relevant to their function. Two critical components of the synaptic junction are the active zone (AZ) and the postsynaptic density (PSD), as they are related to the probability of synaptic release and the number of postsynaptic receptors, respectively. Morphological studies of these structures are greatly facilitated by the use of recent electron microscopy techniques, such as combined focused ion beam milling and scanning electron microscopy (FIB/SEM), and software tools that permit reconstruction of large numbers of synapses in three dimensions. Since the AZ and the PSD are in close apposition and have a similar surface area, they can be represented by a single surface—the synaptic apposition surface (SAS). We have developed an efficient computational technique to automatically extract this surface from synaptic junctions that have previously been three-dimensionally reconstructed from actual tissue samples imaged by automated FIB/SEM. Given its relationship with the release probability and the number of postsynaptic receptors, the surface area of the SAS is a functionally relevant measure of the size of a synapse that can complement other geometrical features like the volume of the reconstructed synaptic junction, the equivalent ellipsoid size and the Feret's diameter. PMID:23847474

Thermal annealing behavior of hydrogen and surface topography of H 2 + ion implanted tungsten

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Jiandong; Jiang, Weilin; Zhu, Zihua

2018-01-25

Tungsten (W) has been proposed as a plasma-facing material (PFM) in fusion reactors due to its outstanding properties. Degradation of the material properties is expected to occur as a result of hydrogen (H) isotope permeation and trapping in W. In this study, two polycrystalline W plates were implanted with 80 keV H 2 + ions to a fluence of 2E21 H+/m2 at room temperature (RT). Time-of-flight secondary ion mass spectrometry (ToF-SIMS), focused ion beam (FIB) and scanning electron microscopy (SEM) were used for sample characterization. The SIMS data shows that H atoms are distributed well beyond the ion projected range.more » Isochronal annealing appears to suggest two H release stages that might be associated with the reported activation energies. H release at RT was observed between days 10 and 70 following ion implantation, and the level was maintained over the next 60 days. In addition, FIB/SEM results exhibit H2 blister formation near the surface of the as-implanted W. The blister distribution remains unchanged after thermal annealing up to 600 °C.« less

Porosity and permeability determination of organic-rich Posidonia shales based on 3-D analyses by FIB-SEM microscopy

NASA Astrophysics Data System (ADS)

Grathoff, Georg H.; Peltz, Markus; Enzmann, Frieder; Kaufhold, Stephan

2016-07-01

The goal of this study is to better understand the porosity and permeability in shales to improve modelling fluid and gas flow related to shale diagenesis. Two samples (WIC and HAD) were investigated, both mid-Jurassic organic-rich Posidonia shales from Hils area, central Germany of different maturity (WIC R0 0.53 % and HAD R0 1.45 %). The method for image collection was focused ion beam (FIB) microscopy coupled with scanning electron microscopy (SEM). For image and data analysis Avizo and GeoDict was used. Porosity was calculated from segmented 3-D FIB based images and permeability was simulated by a Navier Stokes-Brinkman solver in the segmented images. Results show that the quantity and distribution of pore clusters and pores (≥ 40 nm) are similar. The largest pores are located within carbonates and clay minerals, whereas the smallest pores are within the matured organic matter. Orientation of the pores calculated as pore paths showed minor directional differences between the samples. Both samples have no continuous connectivity of pore clusters along the axes in the x, y, and z direction on the scale of 10 to 20 of micrometer, but do show connectivity on the micrometer scale. The volume of organic matter in the studied volume is representative of the total organic carbon (TOC) in the samples. Organic matter does show axis connectivity in the x, y, and z directions. With increasing maturity the porosity in organic matter increases from close to 0 to more than 5 %. These pores are small and in the large organic particles have little connection to the mineral matrix. Continuous pore size distributions are compared with mercury intrusion porosimetry (MIP) data. Differences between both methods are caused by resolution limits of the FIB-SEM and by the development of small pores during the maturation of the organic matter. Calculations show no permeability when only considering visible pores due to the lack of axis connectivity. Adding the organic matter with a background permeability of 1 × 10-21 m2 to the calculations, the total permeability increased by up to 1 order of magnitude for the low mature and decreases slightly for the overmature sample from the gas window. Anisotropy of permeability was observed. Permeability coefficients increase by 1 order of magnitude if simulations are performed parallel to the bedding. Our results compare well with experimental data from the literature suggesting that upscaling may be possible in the future as soon as maturity dependent organic matter permeability coefficients can be determined.

The effect of SEM imaging on the Ar/Ar system in feldspars

NASA Astrophysics Data System (ADS)

Flude, S.; Sherlock, S.; Lee, M.; Kelley, S. P.

2010-12-01

Complex microtextures form in K-feldspar crystals as they cool and are affected by deuteric alteration. This complex structure is the cause of variable closure temperatures for Ar-Ar, a phenomenon which has been utilized in multi domain diffusion (MDD) modelling to recover thermal histories [1]. However, there has been substantial controversy regarding the precise interaction between feldspar microtextures and Ar-diffusion [2,3]. A number of studies have addressed this issue using coupled SEM imaging and Ar/Ar UV laser ablation microprobe (UV-LAMP) analysis on the same sample, to enable direct comparison of microtextures with Ar/Ar age data [4]. Here we have tested the idea that SEM work may affect Ar/Ar ages, leading to inaccurate results in subsequent Ar/Ar analyses. Three splits of alkali feldspar from the Dartmoor Granite in SW England were selected for Ar/Ar UV-LAMP analysis. Split 1 (“control”) was prepared as a polished thick section for Ar/Ar analysis. Split 2 (“SEM”) was prepared as a polished thick section, was chemically-mechanically polished with colloidal silica and underwent SEM imaging (uncoated) and focussed ion beam (FIB) milling (gold coated); electron beam damage in the SEM was maximised by leaving the sample at high magnification for eight minutes. Split 3 (“Etch”) is a cleavage fragment that was etched with HF vapour and underwent low to moderate magnification SEM imaging. The control split gave a range of laser-spot ages consistent with the expected cooling age of the granite and high yields of radiogenic 40Ar* (>90%). The area of the “SEM” split that experienced significant electron beam damage gave younger than expected ages and 40Ar* yields as low as 57%. These are interpreted as a combination of implantation of atmospheric Ar and local redistribution of K within the sample. The area of “SEM” that underwent FIB milling gave ages and 40Ar* yields comparable to the control split, suggesting that the Au-coat minimises FIB damage and that colloidal-polishing and low-magnification SEM imaging do not affect the Ar/Ar system. The “Etch” split gave younger than expected ages and 40Ar* yields as low as 58%, suggesting that HF etching also disrupts the Ar/Ar system. These results suggest that SEM techniques involving intense electron bombardment of an uncoated sample, such as charge contrast imaging and electron backscatter diffraction (EBSD), may disrupt the Ar/Ar system in the sample, leading to spurious results. Etching samples with HF, as is often done for routine Ar/Ar preparation of volcanic phenocrysts, introduces atmospheric Ar and may result in differential loss or gain of K and Ar isotopes, leading to spurious results. References [1] Lovera and Richter, 1989, J. Geophys. Res. 94, 17917-17935. [2] Parsons. et al., 1999, Cont. Min. Pet. 136, 92-110. [3] Mark et al., 2008, Geochim. Cosmochim. Acta, 72 2695-2710. [4] Reddy et al., 2001, Cont. Min. Pet., 141 186-200.

Simulation of the planetary interior differentiation processes in the laboratory.

PubMed

Fei, Yingwei

2013-11-15

A planetary interior is under high-pressure and high-temperature conditions and it has a layered structure. There are two important processes that led to that layered structure, (1) percolation of liquid metal in a solid silicate matrix by planet differentiation, and (2) inner core crystallization by subsequent planet cooling. We conduct high-pressure and high-temperature experiments to simulate both processes in the laboratory. Formation of percolative planetary core depends on the efficiency of melt percolation, which is controlled by the dihedral (wetting) angle. The percolation simulation includes heating the sample at high pressure to a target temperature at which iron-sulfur alloy is molten while the silicate remains solid, and then determining the true dihedral angle to evaluate the style of liquid migration in a crystalline matrix by 3D visualization. The 3D volume rendering is achieved by slicing the recovered sample with a focused ion beam (FIB) and taking SEM image of each slice with a FIB/SEM crossbeam instrument. The second set of experiments is designed to understand the inner core crystallization and element distribution between the liquid outer core and solid inner core by determining the melting temperature and element partitioning at high pressure. The melting experiments are conducted in the multi-anvil apparatus up to 27 GPa and extended to higher pressure in the diamond-anvil cell with laser-heating. We have developed techniques to recover small heated samples by precision FIB milling and obtain high-resolution images of the laser-heated spot that show melting texture at high pressure. By analyzing the chemical compositions of the coexisting liquid and solid phases, we precisely determine the liquidus curve, providing necessary data to understand the inner core crystallization process.

Simulation of the Planetary Interior Differentiation Processes in the Laboratory

PubMed Central

Fei, Yingwei

2013-01-01

A planetary interior is under high-pressure and high-temperature conditions and it has a layered structure. There are two important processes that led to that layered structure, (1) percolation of liquid metal in a solid silicate matrix by planet differentiation, and (2) inner core crystallization by subsequent planet cooling. We conduct high-pressure and high-temperature experiments to simulate both processes in the laboratory. Formation of percolative planetary core depends on the efficiency of melt percolation, which is controlled by the dihedral (wetting) angle. The percolation simulation includes heating the sample at high pressure to a target temperature at which iron-sulfur alloy is molten while the silicate remains solid, and then determining the true dihedral angle to evaluate the style of liquid migration in a crystalline matrix by 3D visualization. The 3D volume rendering is achieved by slicing the recovered sample with a focused ion beam (FIB) and taking SEM image of each slice with a FIB/SEM crossbeam instrument. The second set of experiments is designed to understand the inner core crystallization and element distribution between the liquid outer core and solid inner core by determining the melting temperature and element partitioning at high pressure. The melting experiments are conducted in the multi-anvil apparatus up to 27 GPa and extended to higher pressure in the diamond-anvil cell with laser-heating. We have developed techniques to recover small heated samples by precision FIB milling and obtain high-resolution images of the laser-heated spot that show melting texture at high pressure. By analyzing the chemical compositions of the coexisting liquid and solid phases, we precisely determine the liquidus curve, providing necessary data to understand the inner core crystallization process. PMID:24326245

Analysis and comparison of focused ion beam milling and vibratory polishing sample surface preparation methods for porosity study of U-Mo plate fuel for research and test reactors.

PubMed

Westman, Bjorn; Miller, Brandon; Jue, Jan-Fong; Aitkaliyeva, Assel; Keiser, Dennis; Madden, James; Tucker, Julie D

2018-07-01

Uranium-Molybdenum (U-Mo) low enriched uranium (LEU) fuels are a promising candidate for the replacement of high enriched uranium (HEU) fuels currently in use in a high power research and test reactors around the world. Contemporary U-Mo fuel sample preparation uses focused ion beam (FIB) methods for analysis of fission gas porosity. However, FIB possess several drawbacks, including reduced area of analysis, curtaining effects, and increased FIB operation time and cost. Vibratory polishing is a well understood method for preparing large sample surfaces with very high surface quality. In this research, fission gas porosity image analysis results are compared between samples prepared using vibratory polishing and FIB milling to assess the effectiveness of vibratory polishing for irradiated fuel sample preparation. Scanning electron microscopy (SEM) imaging was performed on sections of irradiated U-Mo fuel plates and the micrographs were analyzed using a fission gas pore identification and measurement script written in MatLab. Results showed that the vibratory polishing method is preferentially removing material around the edges of the pores, causing the pores to become larger and more rounded, leading to overestimation of the fission gas porosity size. Whereas, FIB preparation tends to underestimate due to poor micrograph quality and surface damage leading to inaccurate segmentations. Despite the aforementioned drawbacks, vibratory polishing remains a valid method for porosity analysis sample preparation, however, improvements should be made to reduce the preferential removal of material surrounding pores in order to minimize the error in the porosity measurements. Copyright © 2018 Elsevier Ltd. All rights reserved.

Integration of a high-NA light microscope in a scanning electron microscope.

PubMed

Zonnevylle, A C; Van Tol, R F C; Liv, N; Narvaez, A C; Effting, A P J; Kruit, P; Hoogenboom, J P

2013-10-01

We present an integrated light-electron microscope in which an inverted high-NA objective lens is positioned inside a scanning electron microscope (SEM). The SEM objective lens and the light objective lens have a common axis and focal plane, allowing high-resolution optical microscopy and scanning electron microscopy on the same area of a sample simultaneously. Components for light illumination and detection can be mounted outside the vacuum, enabling flexibility in the construction of the light microscope. The light objective lens can be positioned underneath the SEM objective lens during operation for sub-10 μm alignment of the fields of view of the light and electron microscopes. We demonstrate in situ epifluorescence microscopy in the SEM with a numerical aperture of 1.4 using vacuum-compatible immersion oil. For a 40-nm-diameter fluorescent polymer nanoparticle, an intensity profile with a FWHM of 380 nm is measured whereas the SEM performance is uncompromised. The integrated instrument may offer new possibilities for correlative light and electron microscopy in the life sciences as well as in physics and chemistry. © 2013 The Authors Journal of Microscopy © 2013 Royal Microscopical Society.

FIB-tomographic studies on chemical vapor deposition grown SnO2 nanowire arrays on TiO2 (001)

NASA Astrophysics Data System (ADS)

Chen, Haoyun; Liu, Yi; Wu, Hong; Xiong, Xiang; Pan, Jun

2016-12-01

Tin oxide nanowire arrays on titania (001) have been successfully fabricated by chemical vapor deposition of Sn(O t Bu)4 precursor. The morphologies and structures of ordered SnO2 nanowires (NWs) were analyzed by cross-sectional SEM, HR-TEM and AFM. An FIB-tomography technique was applied in order to reconstruct a 3D presentation of ordered SnO2 nanowires. The achieved 3D analysis showed the spatial orientation and angles of ordered SnO2 NWs can be obtained in a one-shot experiment, and the distribution of Au catalysts showed the competition between 1D and 2D growth. The SnO2 nanowire arrays can be potentially used as a diameter- and surface-dependent sensing unit for the detection of gas- and bio-molecules.

Strategies for gallium removal after focused ion beam patterning of ferroelectric oxide nanostructures

NASA Astrophysics Data System (ADS)

Schilling, A.; Adams, T.; Bowman, R. M.; Gregg, J. M.

2007-01-01

As part of a study into the properties of ferroelectric single crystals at nanoscale dimensions, the effects that focused ion beam (FIB) processing can have, in terms of structural damage and ion implantation, on perovskite oxide materials has been examined, and a post-processing procedure developed to remove such effects. Single crystal material of the perovskite ferroelectric barium titanate (BaTiO3) has been patterned into thin film lamellae structures using a FIB microscope. Previous work had shown that FIB patterning induced gallium impregnation and associated creation of amorphous layers in a surface region of the single crystal material some 20 nm thick, but that both recrystallization and expulsion of gallium could be achieved through thermal annealing in air. Here we confirm this observation, but find that thermally induced gallium expulsion is associated with the formation of gallium-rich platelets on the surface of the annealed material. These platelets are thought to be gallium oxide. Etching using nitric and hydrochloric acids had no effect on the gallium-rich platelets. Effective platelet removal involved thermal annealing at 700 °C for 1 h in a vacuum followed by 1 h in oxygen, and then a post-annealing low-power plasma clean in an Ar/O atmosphere. Similar processing is likely to be necessary for the full recovery of post FIB-milled nanostructures in oxide ceramic systems in general.

Fabrication of Metallic Quantum Dot Arrays For Nanoscale Nonlinear Optics

NASA Astrophysics Data System (ADS)

McMahon, M. D.; Hmelo, A. B.; Lopez Magruder, R., III; Weller Haglund, R. A., Jr.; Feldman, L. C.

2003-03-01

Ordered arrays of metal nanocrystals embedded in or sequestered on dielectric hosts have potential applications as elements of nonlinear or near-field optical circuits, as sensitizers for fluorescence emitters and photo detectors, and as anchor points for arrays of biological molecules. Metal nanocrystals are strongly confined electronic systems with size-, shape and spatial orientation-dependent optical responses. At the smallest scales (below about 15 nm diameter), their band structure is drastically altered by the small size of the system, and the reduced population of conduction-band electrons. Here we report on the fabrication of two-dimensional ordered metallic nanocrystal arrays, and one-dimensional nanocrystal-loaded waveguides for optical investigations. We have employed strategies for synthesizing metal nanocrystal composites that capitalize on the best features of focused ion beam (FIB) machining and pulsed laser deposition (PLD). The FIB generates arrays of specialized sites; PLD vapor deposition results in the directed self-assembly of Ag nanoparticles nucleated at the FIB generated sites on silicon substrates. We present results based on the SEM, AFM and optical characterization of prototype composites. This research has been supported by the U.S. Department of Energy under grant DE-FG02-01ER45916.

Diversity in C-Xanes Spectra Obtained from Carbonaceous Solid Inclusions from Monahans Halite

NASA Technical Reports Server (NTRS)

Kebukawa, Y.; Zolensky, M. E.; Fries, M.; Kilcoyne, A. L. D.; Rahman, Z.; Cody, G. D.

2014-01-01

Monahans meteorite (H5) contains fluid inclusion- bearing halite (NaCl) crystals [1]. Microthermometry and Raman spectroscopy showed that the fluid in the inclusions is an aqueous brine and they were trapped near 25degC [1]. Their continued presence in the halite grains requires that their incorporation into the H chondrite asteroid was post metamorphism [2]. Abundant solid inclusions are also present in the halites. The solid inclusions include abundant and widely variable organics [2]. Analyses by Raman microprobe, SEM/EDX, synchrotron X-ray diffraction and TEM reveal that these grains include macromolecular carbon similar in structure to CV3 chondrite matrix carbon, aliphatic carbon compounds, olivine (Fo99-59), high- and low-Ca pyroxene, feldspars, magnetite, sulfides, lepidocrocite, carbonates, diamond, apatite and possibly the zeolite phillipsite [3]. Here we report organic analyses of these carbonaceous residues in Monahans halite using C-, N-, and O- X-ray absorption near edge structure (XANES). Samples and Methods: Approximately 100 nm-thick sections were extracted with a focused ion beam (FIB) at JSC from solid inclusions from Monahans halite. The sections were analyzed using the scanning transmission X-ray microscope (STXM) on beamline 5.3.2.2 at the Advanced Light Source, Lawrence Berkeley National Laboratory for XANES spectroscopy. Results and Discussion: C-XANES spectra of the solid inclusions show micrometer-scale heterogeneity, indicating that the macromolecular carbon in the inclusions have complex chemical variations. C-XANES features include 284.7 eV assigned to aromatic C=C, 288.4-288.8 eV assigned to carboxyl, and 290.6 eV assigned to carbonate. The carbonyl features obtained by CXANES might have been caused by the FIB used in sample preparation. No specific N-XANES features are observed. The CXANES spectra obtained from several areas in the FIB sections include type 1&2 chondritic IOM like, type 3 chondritic IOM like, and none of the above. The natures of the macromolecular carbon in the solid inclusions observed by C-XANES are consistent with the previous studies showing that the carbonaceous solid inclusions have not originated from Monahans parent body [1-3], and have various origins, including various chondritic meteorite parent bodies as well as other unknown source(s).

FIB-NanoSIMS-TEM Coordinated Study of a Wark-Lovering Rim in a Vigarano Type A CAI

NASA Technical Reports Server (NTRS)

Cai, A.; Ito, M.; Keller, L. P.; Ross, D. K.; Nakamura-Messenger, K.

2010-01-01

Wark-Lovering (WL) rims are thin multi layered mineral sequences that surround most Ca, Al-rich inclusions (CAIs). Unaltered WL rims are composed of the same primary high temperature minerals as CAIs, such as melilite, spinel, pyroxene, hibonite, perovskite, anorthite and olivine. It is still unclear whether the rim minerals represent a different generation formed by a separate event from their associated CAIs or are a byproduct of CAI formation. Several models have been proposed for the origins of WL rims including condensation, flashheating, reaction of a CAI with a Mg-Si-rich reservoir (nebular gas or solid); on the basis of mineralogy, abundances of trace elements, O and Mg isotopic studies. Detailed mineralogical characterizations of WL rims at micrometer to nanometer scales have been obtained by TEM observations, but so far no coordinated isotopic - mineralogical studies have been performed. Thus, we have applied an O isotopic imaging technique by NanoSIMS 50L to investigate heterogeneous distributions of O isotopic ratios in minerals within a cross section of a WL rim prepared using a focused ion beam (FIB) instrument. After the isotopic measurements, we determine the detailed mineralogy and microstructure of the same WL FIB section to gain insight into its petrogenesis. Here we present preliminary results from O isotopic and elemental maps by NanoSIMS and mineralogical analysis by FE-SEM of a FIB section of a WL rim in the Vigarano reduced CV3 chondrite.

Bending spring rate investigation of nanopipette for cell injection.

PubMed

Shen, Yajing; Zhang, Zhenhai; Fukuda, Toshio

2015-04-17

Bending of nanopipette tips during cell penetration is a major cause of cell injection failure. However, the flexural rigidity of nanopipettes is little known due to their irregular structure. In this paper, we report a quantitative method to estimate the flexural rigidity of a nanopipette by investigating its bending spring rate. First nanopipettes with a tip size of 300 nm are fabricated from various glass tubes by laser pulling followed by focused ion beam (FIB) milling. Then the bending spring rate of the nanopipettes is investigated inside a scanning electron microscope (SEM). Finally, a yeast cell penetration test is performed on these nanopipettes, which have different bending spring rates. The results show that nanopipettes with a higher bending spring rate have better cell penetration capability, which confirms that the bending spring rate may well reflect the flexural rigidity of a nanopipette. This method provides a quantitative parameter for characterizing the mechanical property of a nanopipette that can be potentially taken as a standard specification in the future. This general method can also be used to estimate other one-dimensional structures for cell injection, which will greatly benefit basic cell biology research and clinical applications.

Bending spring rate investigation of nanopipette for cell injection

NASA Astrophysics Data System (ADS)

Shen, Yajing; Zhang, Zhenhai; Fukuda, Toshio

2015-04-01

Bending of nanopipette tips during cell penetration is a major cause of cell injection failure. However, the flexural rigidity of nanopipettes is little known due to their irregular structure. In this paper, we report a quantitative method to estimate the flexural rigidity of a nanopipette by investigating its bending spring rate. First nanopipettes with a tip size of 300 nm are fabricated from various glass tubes by laser pulling followed by focused ion beam (FIB) milling. Then the bending spring rate of the nanopipettes is investigated inside a scanning electron microscope (SEM). Finally, a yeast cell penetration test is performed on these nanopipettes, which have different bending spring rates. The results show that nanopipettes with a higher bending spring rate have better cell penetration capability, which confirms that the bending spring rate may well reflect the flexural rigidity of a nanopipette. This method provides a quantitative parameter for characterizing the mechanical property of a nanopipette that can be potentially taken as a standard specification in the future. This general method can also be used to estimate other one-dimensional structures for cell injection, which will greatly benefit basic cell biology research and clinical applications.

Evolution of residual stress, free volume, and hardness in the laser shock peened Ti-based metallic glass

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Liang; Wang, Lu; Nie, Zhihua

Laser shock peening (LSP) with different cycles was performed on the Ti-based bulk metallic glasses (BMGs). The sub-surface residual stress of the LSPed specimens was measured by high-energy X-ray diffraction (HEXRD) and the near-surface residual stress was measured by scanning electron microscope/focused ion beam (SEM/FIB) instrument. The sub-surface residual stress in the LSP impact direction (about-170MPa) is much lower than that perpendicular to the impact direction (about -350 MPa), exhibiting anisotropy. The depth of the compressive stress zone increases from 400 mu m to 500 mu m with increasing LSP cycles. The highest near-surface residual stress is about -750 MPa.more » LSP caused the free volume to increase and the maximum increase appeared after the first LSP process. Compared with the hardness (567 +/- 7 HV) of the as-cast BMG, the hardness (590 +/- 9 HV) on the shocked surface shows a hardening effect due to the hardening mechanism of compressive residual stress; and the hardness (420 +/- 9 HV) on the longitudinal section shows a softening effect due to the softening mechanism of free volume.« less

Three dimensional profile measurement using multi-channel detector MVM-SEM

NASA Astrophysics Data System (ADS)

Yoshikawa, Makoto; Harada, Sumito; Ito, Keisuke; Murakawa, Tsutomu; Shida, Soichi; Matsumoto, Jun; Nakamura, Takayuki

2014-07-01

In next generation lithography (NGL) for the 1x nm node and beyond, the three dimensional (3D) shape measurements such as side wall angle (SWA) and height of feature on photomask become more critical for the process control. Until today, AFM (Atomic Force Microscope), X-SEM (cross-section Scanning Electron Microscope) and TEM (Transmission Electron Microscope) tools are normally used for 3D measurements, however, these techniques require time-consuming preparation and observation. And both X-SEM and TEM are destructive measurement techniques. This paper presents a technology for quick and non-destructive 3D shape analysis using multi-channel detector MVM-SEM (Multi Vision Metrology SEM), and also reports its accuracy and precision.

Quantification of the degradation of Ni-YSZ anodes upon redox cycling

NASA Astrophysics Data System (ADS)

Song, Bowen; Ruiz-Trejo, Enrique; Bertei, Antonio; Brandon, Nigel P.

2018-01-01

Ni-YSZ anodes for Solid Oxide Fuel Cells are vulnerable to microstructural damage during redox cycling leading to a decrease in the electrochemical performance. This study quantifies the microstructural changes as a function of redox cycles at 800 °C and associates it to the deterioration of the mechanical properties and polarisation resistance. A physically-based model is used to estimate the triple-phase boundary (TPB) length from impedance spectra, and satisfactorily matches the TPB length quantified by FIB-SEM tomography: within 20 redox cycles, the TPB density decreases from 4.63 μm-2 to 1.06 μm-2. Although the polarisation resistance increases by an order of magnitude after 20 cycles, after each re-reduction the electrode polarisation improves consistently due to the transient generation of Ni nanoparticles around the TPBs. Nonetheless, the long-term degradation overshadows this transient improvement due to the nickel agglomeration. In addition, FIB-SEM tomography reveals fractures along YSZ grain boundaries, Ni-YSZ detachment and increased porosity in the composite that lead to irreversible mechanical damage: the elastic modulus diminishes from 36.4 GPa to 20.2 GPa and the hardness from 0.40 GPa to 0.15 GPa. These results suggest that microstructural, mechanical and electrochemical properties are strongly interdependent in determining the degradation caused by redox cycling.

Structural analysis of reactionary dentin formed in response to polymicrobial invasion

PubMed Central

Charadram, Nattida; Austin, Christine; Trimby, Patrick; Simonian, Mary; Swain, Michael V.; Hunter, Neil

2013-01-01

In response to microbial invasion of dentin odontoblasts secrete an altered calcified matrix termed reactionary dentin (Rd). 3D reconstruction of focused-ion-beam scanning electron microscopy (FIB-SEM) image slices revealed helical tubular structures in Rd that contrasted with regular cylindrical tubules characteristic of dentin from healthy teeth and affected so-called physiological dentin (Pd) lying exterior to Rd. This helical structure in Rd provided effective constriction of tubule lumen diameter that formed a barrier to bacterial advance towards the dental pulp. SEM of resin cast preparations revealed altered extension of odontoblast processes through Rd. The distribution of key mineral elements was studied by combination of 3D reconstruction of focused-ion-beam based X-ray microanalysis (FIB-EDS), laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). There was a marked redistribution of calcium and phosphorous in Rd together with an increase of diffusely deposited magnesium compatible with the mineral deposition phase of synthesis of this altered matrix. Changes in tubule structure and mineral content characteristic of Rd are consistent with reduced hardness and lower elastic modulus reported for this matrix. Findings provide insight into the unique structure of Rd synthesised as a primary response to infection. PMID:23261402

Mechanisms of material removal and mass transport in focused ion beam nanopore formation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Das, Kallol, E-mail: das7@illinois.edu; Johnson, Harley T., E-mail: htj@illinois.edu; Freund, Jonathan B., E-mail: jbfreund@illinois.edu

2015-02-28

Despite the widespread use of focused ion beam (FIB) processing as a material removal method for applications ranging from electron microscope sample preparation to nanopore processing for DNA sequencing, the basic material removal mechanisms of FIB processing are not well understood. We present the first complete atomistic simulation of high-flux FIB using large-scale parallel molecular dynamics (MD) simulations of nanopore fabrication in freestanding thin films. We focus on the root mechanisms of material removal and rearrangement and describe the role of explosive boiling in forming nanopores. FIB nanopore fabrication is typically understood to occur via sputter erosion. This can bemore » shown to be the case in low flux systems, where individual ion impacts are sufficiently separated in time that they may be considered as independent events. But our detailed MD simulations show that in high flux FIB processing, above a threshold level at which thermal effects become significant, the primary mechanism of material removal changes to a significantly accelerated, thermally dominated process. Under these conditions, the target is heated by the ion beam faster than heat is conducted away by the material, leading quickly to melting, and then continued heating to nearly the material critical temperature. This leads to explosive boiling of the target material with spontaneous bubble formation and coalescence. Mass is rapidly rearranged at the atomistic scale, and material removal occurs orders of magnitude faster than would occur by simple sputtering. While the phenomenology is demonstrated computationally in silicon, it can be expected to occur at lower beam fluxes in other cases where thermal conduction is suppressed due to material properties, geometry, or ambient thermal conditions.« less

Characterization of calcium crystals in Abelia using x-ray diffraction and electron microscopes

USDA-ARS?s Scientific Manuscript database

Localization, chemical composition, and morphology of calcium crystals in leaves and stems of Abelia mosanensis and A. ×grandiflora were analyzed with a variable pressure scanning electron microscope (VP-SEM) equipped with an X-ray diffraction system, low temperature SEM (LT-SEM) and a transmission ...

Development of a SEM-based low-energy in-line electron holography microscope for individual particle imaging.

PubMed

Adaniya, Hidehito; Cheung, Martin; Cassidy, Cathal; Yamashita, Masao; Shintake, Tsumoru

2018-05-01

A new SEM-based in-line electron holography microscope has been under development. The microscope utilizes conventional SEM and BF-STEM functionality to allow for rapid searching of the specimen of interest, seamless interchange between SEM, BF-STEM and holographic imaging modes, and makes use of coherent low-energy in-line electron holography to obtain low-dose, high-contrast images of light element materials. We report here an overview of the instrumentation and first experimental results on gold nano-particles and carbon nano-fibers for system performance tests. Reconstructed images obtained from the holographic imaging mode of the new microscope show substantial image contrast and resolution compared to those acquired by SEM and BF-STEM modes, demonstrating the feasibility of high-contrast imaging via low-energy in-line electron holography. The prospect of utilizing the new microscope to image purified biological specimens at the individual particle level is discussed and electron optical issues and challenges to further improve resolution and contrast are considered. Copyright © 2018 Elsevier B.V. All rights reserved.

Contributions of Stress and Oxidation on the Formation of Whiskers in Pb-free Solders

DTIC Science & Technology

2016-01-29

environmental factors influencing formation of tin whiskers on electrodeposited lead free, tin coatings over copper (or copper containing) substrates is the...Oxidation on the Formation of Whiskers in Pb‐free Solders,” WP-1754 15. SUBJECT TERMS Tin Whiskers, Residual Stress, Environmental Degradation 16...showing the surface of a tin film with whisker .................... 2 Figure 2: SEM Micrograph of Tin film on Copper Substrate cross-sectioned by FIB

Prize for Industrial Applications of Physics Talk: Low energy spread Ion source for focused ion beam systems-Search for the holy grail

NASA Astrophysics Data System (ADS)

Ward, Bill

2011-03-01

In this talk I will cover my personal experiences as a serial entrepreneur and founder of a succession of focused ion beam companies (1). Ion Beam Technology, which developed a 200kv (FIB) direct ion implanter (2). Micrion, where the FIB found a market in circuit edit and mask repair, which eventually merged with FEI corporation. and (3). ALIS Corporation which develop the Orion system, the first commercially successful sub-nanometer helium ion microscope, that was ultimately acquired by Carl Zeiss corporation. I will share this adventure beginning with my experiences in the early days of ion beam implantation and e-beam lithography which lead up to the final breakthrough understanding of the mechanisms that govern the successful creation and operation of a single atom ion source.

Characteristics of different frequency ranges in scanning electron microscope images

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sim, K. S., E-mail: kssim@mmu.edu.my; Nia, M. E.; Tan, T. L.

2015-07-22

We demonstrate a new approach to characterize the frequency range in general scanning electron microscope (SEM) images. First, pure frequency images are generated from low frequency to high frequency, and then, the magnification of each type of frequency image is implemented. By comparing the edge percentage of the SEM image to the self-generated frequency images, we can define the frequency ranges of the SEM images. Characterization of frequency ranges of SEM images benefits further processing and analysis of those SEM images, such as in noise filtering and contrast enhancement.

Multi Length Scale Imaging of Flocculated Estuarine Sediments; Insights into their Complex 3D Structure

NASA Astrophysics Data System (ADS)

Wheatland, Jonathan; Bushby, Andy; Droppo, Ian; Carr, Simon; Spencer, Kate

2015-04-01

Suspended estuarine sediments form flocs that are compositionally complex, fragile and irregularly shaped. The fate and transport of suspended particulate matter (SPM) is determined by the size, shape, density, porosity and stability of these flocs and prediction of SPM transport requires accurate measurements of these three-dimensional (3D) physical properties. However, the multi-scaled nature of flocs in addition to their fragility makes their characterisation in 3D problematic. Correlative microscopy is a strategy involving the spatial registration of information collected at different scales using several imaging modalities. Previously, conventional optical microscopy (COM) and transmission electron microscopy (TEM) have enabled 2-dimensional (2D) floc characterisation at the gross (> 1 µm) and sub-micron scales respectively. Whilst this has proven insightful there remains a critical spatial and dimensional gap preventing the accurate measurement of geometric properties and an understanding of how structures at different scales are related. Within life sciences volumetric imaging techniques such as 3D micro-computed tomography (3D µCT) and focused ion beam scanning electron microscopy [FIB-SEM (or FIB-tomography)] have been combined to characterise materials at the centimetre to micron scale. Combining these techniques with TEM enables an advanced correlative study, allowing material properties across multiple spatial and dimensional scales to be visualised. The aims of this study are; 1) to formulate an advanced correlative imaging strategy combining 3D µCT, FIB-tomography and TEM; 2) to acquire 3D datasets; 3) to produce a model allowing their co-visualisation; 4) to interpret 3D floc structure. To reduce the chance of structural alterations during analysis samples were first 'fixed' in 2.5% glutaraldehyde/2% formaldehyde before being embedding in Durcupan resin. Intermediate steps were implemented to improve contrast and remove pore water, achieved by the addition of heavy metal stains and washing samples in a series of ethanol solutions and acetone. Gross-scale characterisation involved scanning samples using a Nikon Metrology HM X 225 µCT. For micro-scale analysis a working surface was revealed by microtoming the sample. Ultrathin sections were then collected and analysed using a JEOL 1200 Ex II TEM, and FIB-tomography datasets obtained using an FEI Quanta 3D FIB-SEM. Finally, to locate the surface and relate TEM and FIB-tomography datasets to the original floc, samples were rescanned using the µCT. Image processing was initially conducted in ImageJ. Following this datasets were imported into Amira 5.5 where pixel intensity thresholding allowed particle-matrix boundaries to be defined. Using 'landmarks' datasets were then registered to enable their co-visualisation in 3D models. Analysis of registered datasets reveals the complex non-fractal nature of flocs, whose properties span several of orders of magnitude. Primary particles are organised into discrete 'bundles', the arrangement of which directly influences their gross morphology. This strategy, which allows the co-visualisation of spatially registered multi-scale 3D datasets, provides unique insights into the true nature floc which would other have been impossible.

A versatile atomic force microscope integrated with a scanning electron microscope.

PubMed

Kreith, J; Strunz, T; Fantner, E J; Fantner, G E; Cordill, M J

2017-05-01

A versatile atomic force microscope (AFM), which can be installed in a scanning electron microscope (SEM), is introduced. The flexible design of the instrument enables correlated analysis for different experimental configurations, such as AFM imaging directly after nanoindentation in vacuum. In order to demonstrate the capabilities of the specially designed AFM installed inside a SEM, slip steps emanating around nanoindents in single crystalline brass were examined. This example showcases how the combination of AFM and SEM imaging can be utilized for quantitative dislocation analysis through the measurement of the slip step heights without the hindrance of oxide formation. Finally, an in situ nanoindentation technique is introduced, illustrating the use of AFM imaging during indentation experiments to examine plastic deformation occurring under the indenter tip. The mechanical indentation data are correlated to the SEM and AFM images to estimate the number of dislocations emitted to the surface.

Nanoscale Experimental Characterization and 3D Mechanistic Modeling of Shale with Quantified Heterogeneity

NASA Astrophysics Data System (ADS)

Bennett, K. C.; Borja, R. I.

2014-12-01

Shale is a fine-grained sedimentary rock consisting primarily of clay and silt, and is of particular interest with respect to hydrocarbon production as both a source and seal rock. The deformation and fracture properties of shale depend on the mechanical properties of its basic constituents, including solid clay particles, inclusions such as silt and organics, and multiscale porosity. This paper presents the results of a combined experimental/numerical investigation into the mechanical behavior of shale at the nanoscale. Large grids of nanoindentation tests, spanning various length scales ranging from 200-20000 nanometers deep, were performed on a sample of Woodford shale in both the bedding plane normal (BPN) and bedding plane parallel (BPP) directions. The nanoindentions were performed in order to determine the mechanical properties of the constituent materials in situ as well as those of the highly heterogeneous composite material at this scale. Focused ion beam (FIB) milling and scanning electron microscopy (SEM) were used in conjunction (FIB-SEM) to obtain 2D and 3D images characterizing the heterogeneity of the shale at this scale. The constituent materials were found to be best described as consisting of near micrometer size clay and silt particles embedded in a mixed organic/clay matrix, with some larger (near 10 micrometers in diameter) pockets of organic material evident. Indented regions were identified through SEM, allowing the 200-1000 nanometer deep indentations to be classified according to the constituent materials which they engaged. We use nonlinear finite element modeling to capture results of low-load (on the order of milliNewtons) and high-load (on the order of a few Newtons) nanoindentation tests. Experimental results are used to develop a 3D mechanistic model that interprets the results of nanoindentation tests on specimens of Woodford shale with quantified heterogeneity.

3D Analysis of HCMV Induced-Nuclear Membrane Structures by FIB/SEM Tomography: Insight into an Unprecedented Membrane Morphology

PubMed Central

Villinger, Clarissa; Neusser, Gregor; Kranz, Christine; Walther, Paul; Mertens, Thomas

2015-01-01

We show that focused ion beam/scanning electron microscopy (FIB/SEM) tomography is an excellent method to analyze the three-dimensional structure of a fibroblast nucleus infected with human cytomegalovirus (HCMV). We found that the previously described infoldings of the inner nuclear membrane, which are unique among its kind, form an extremely complex network of membrane structures not predictable by previous two-dimensional studies. In all cases they contained further invaginations (2nd and 3rd order infoldings). Quantification revealed 5498 HCMV capsids within two nuclear segments, allowing an estimate of 15,000 to 30,000 capsids in the entire nucleus five days post infection. Only 0.8% proved to be enveloped capsids which were exclusively detected in 1st order infoldings (perinuclear space). Distribution of the capsids between 1st, 2nd and 3rd order infoldings is in complete agreement with the envelopment/de-envelopment model for egress of HCMV capsids from the nucleus and we confirm that capsid budding does occur at the large infoldings. Based on our results we propose the pushing membrane model: HCMV infection induces local disruption of the nuclear lamina and synthesis of new membrane material which is pushed into the nucleoplasm, forming complex membrane infoldings in a highly abundant manner, which then may be also used by nucleocapsids for budding. PMID:26556360

Self-diffusion of electrolyte species in model battery electrodes using Magic Angle Spinning and Pulsed Field Gradient Nuclear Magnetic Resonance

NASA Astrophysics Data System (ADS)

Tambio, Sacris Jeru; Deschamps, Michaël; Sarou-Kanian, Vincent; Etiemble, Aurélien; Douillard, Thierry; Maire, Eric; Lestriez, Bernard

2017-09-01

Lithium-ion batteries are electrochemical storage devices using the electrochemical activity of the lithium ion in relation to intercalation compounds owing to mass transport phenomena through diffusion. Diffusion of the lithium ion in the electrode pores has been poorly understood due to the lack of experimental techniques for measuring its self-diffusion coefficient in porous media. Magic-Angle Spinning, Pulsed Field Gradient, Stimulated-Echo Nuclear Magnetic Resonance (MAS-PFG-STE NMR) was used here for the first time to measure the self-diffusion coefficients of the electrolyte species in the LP30 battery electrolyte (i.e. a 1 M solution of LiPF6 dissolved in 1:1 Ethylene Carbonate - Dimethyl Carbonate) in model composites. These composite electrodes were made of alumina, carbon black and PVdF-HFP. Alumina's magnetic susceptibility is close to the measured magnetic susceptibility of the LP30 electrolyte thereby limiting undesirable internal field gradients. Interestingly, the self-diffusion coefficient of lithium ions decreases with increasing carbon content. FIB-SEM was used to describe the 3D geometry of the samples. The comparison between the reduction of self-diffusion coefficients as measured by PFG-NMR and as geometrically derived from FIB/SEM tortuosity values highlights the contribution of specific interactions at the material/electrolyte interface on the lithium transport properties.

Developing 3D SEM in a broad biological context

PubMed Central

Kremer, A; Lippens, S; Bartunkova, S; Asselbergh, B; Blanpain, C; Fendrych, M; Goossens, A; Holt, M; Janssens, S; Krols, M; Larsimont, J-C; Mc Guire, C; Nowack, MK; Saelens, X; Schertel, A; Schepens, B; Slezak, M; Timmerman, V; Theunis, C; Van Brempt, R; Visser, Y; GuÉRin, CJ

2015-01-01

When electron microscopy (EM) was introduced in the 1930s it gave scientists their first look into the nanoworld of cells. Over the last 80 years EM has vastly increased our understanding of the complex cellular structures that underlie the diverse functions that cells need to maintain life. One drawback that has been difficult to overcome was the inherent lack of volume information, mainly due to the limit on the thickness of sections that could be viewed in a transmission electron microscope (TEM). For many years scientists struggled to achieve three-dimensional (3D) EM using serial section reconstructions, TEM tomography, and scanning EM (SEM) techniques such as freeze-fracture. Although each technique yielded some special information, they required a significant amount of time and specialist expertise to obtain even a very small 3D EM dataset. Almost 20 years ago scientists began to exploit SEMs to image blocks of embedded tissues and perform serial sectioning of these tissues inside the SEM chamber. Using first focused ion beams (FIB) and subsequently robotic ultramicrotomes (serial block-face, SBF-SEM) microscopists were able to collect large volumes of 3D EM information at resolutions that could address many important biological questions, and do so in an efficient manner. We present here some examples of 3D EM taken from the many diverse specimens that have been imaged in our core facility. We propose that the next major step forward will be to efficiently correlate functional information obtained using light microscopy (LM) with 3D EM datasets to more completely investigate the important links between cell structures and their functions. Lay Description Life happens in three dimensions. For many years, first light, and then EM struggled to image the smallest parts of cells in 3D. With recent advances in technology and corresponding improvements in computing, scientists can now see the 3D world of the cell at the nanoscale. In this paper we present the results of high resolution 3D imaging in a number of diverse cells and tissues from multiple species. 3D reconstructions of cell structures often revealed them to be significantly more complex when compared to extrapolations made from 2D studies. Correlating functional 3D LM studies with 3D EM results opens up the possibility of making new strides in our understanding of how cell structure is connected to cell function. PMID:25623622

Newly recognized hosts for uranium in the Hanford Site vadose zone

USGS Publications Warehouse

Stubbs, J.E.; Veblen, L.A.; Elbert, D.C.; Zachara, J.M.; Davis, J.A.; Veblen, D.R.

2009-01-01

Uranium contaminated sediments from the U.S. Department of Energy's Hanford Site have been investigated using electron microscopy. Six classes of solid hosts for uranium were identified. Preliminary sediment characterization was carried out using optical petrography, and electron microprobe analysis (EMPA) was used to locate materials that host uranium. All of the hosts are fine-grained and intergrown with other materials at spatial scales smaller than the analytical volume of the electron microprobe. A focused ion beam (FIB) was used to prepare electron-transparent specimens of each host for the transmission electron microscope (TEM). The hosts were identified as: (1) metatorbernite [Cu(UO2)2(PO4)2??8H2O]; (2) coatings on sediment clasts comprised mainly of phyllosilicates; (3) an amorphous zirconium (oxyhydr)oxide found in clast coatings; (4) amorphous and poorly crystalline materials that line voids within basalt lithic fragments; (5) amorphous palagonite surrounding fragments of basaltic glass; and (6) Fe- and Mn-oxides. These findings demonstrate the effectiveness of combining EMPA, FIB, and TEM to identify solid-phase contaminant hosts. Furthermore, they highlight the complexity of U geochemistry in the Hanford vadose zone, and illustrate the importance of microscopic transport in controlling the fate of contaminant metals in the environment. ?? 2008 Elsevier Ltd.

Molecular dynamics and dynamic Monte-Carlo simulation of irradiation damage with focused ion beams

NASA Astrophysics Data System (ADS)

Ohya, Kaoru

2017-03-01

The focused ion beam (FIB) has become an important tool for micro- and nanostructuring of samples such as milling, deposition and imaging. However, this leads to damage of the surface on the nanometer scale from implanted projectile ions and recoiled material atoms. It is therefore important to investigate each kind of damage quantitatively. We present a dynamic Monte-Carlo (MC) simulation code to simulate the morphological and compositional changes of a multilayered sample under ion irradiation and a molecular dynamics (MD) simulation code to simulate dose-dependent changes in the backscattering-ion (BSI)/secondary-electron (SE) yields of a crystalline sample. Recent progress in the codes for research to simulate the surface morphology and Mo/Si layers intermixing in an EUV lithography mask irradiated with FIBs, and the crystalline orientation effect on BSI and SE yields relating to the channeling contrast in scanning ion microscopes, is also presented.

Structural, mechanical and corrosion studies of Cr-rich inclusions in 152 cladding of dissimilar metal weld joint

NASA Astrophysics Data System (ADS)

Li, Yifeng; Wang, Jianqiu; Han, En-Hou; Yang, Chengdong

2018-01-01

Cr-rich inclusions were discovered in 152 cladding at the inner wall of domestic dissimilar metal weld joint, and their morphologies, microstructures, mechanical properties and corrosion behaviors were systematically characterized by SEM, TEM, nanoindentation and FIB. The results indicate that the Cr-rich inclusions originate from large-size Cr particles in 152 welding electrode flux, and they are 50-150 μm in size in most cases, and there is a continuous transition zone of 2-5 μm in width between the Cr inclusion core and 152 cladding matrix, and the transition zone consists of Ni & Fe-rich dendritic austenite and Cr23C6 and Cr matrix. The transition zone has the highest nanoindentation hardness (7.66 GPa), which is much harder than the inclusion core (5.14 GPa) and 152 cladding (3.71 GPa). In-situ microscopic tensile tests show that cracks initialize preferentially in transition zone, and then propagate into the inclusion core, and creep further into 152 cladding after penetrating the core area. The inclusion core and its transition zone both share similar oxide film structure with nickel-base 152 cladding matrix in simulated primary water, while those two parts present better general corrosion resistance than 152 cladding matrix due to higher Cr concentration.

Scanning electron microscope observation of dislocations in semiconductor and metal materials.

PubMed

Kuwano, Noriyuki; Itakura, Masaru; Nagatomo, Yoshiyuki; Tachibana, Shigeaki

2010-08-01

Scanning electron microscope (SEM) image contrasts have been investigated for dislocations in semiconductor and metal materials. It is revealed that single dislocations can be observed in a high contrast in SEM images formed by backscattered electrons (BSE) under the condition of a normal configuration of SEM. The BSE images of dislocations were compared with those of the transmission electron microscope and scanning transmission electron microscope (STEM) and the dependence of BSE image contrast on the tilting of specimen was examined to discuss the origin of image contrast. From the experimental results, it is concluded that the BSE images of single dislocations are attributed to the diffraction effect and related with high-angle dark-field images of STEM.

Xenon gas field ion source from a single-atom tip

NASA Astrophysics Data System (ADS)

Lai, Wei-Chiao; Lin, Chun-Yueh; Chang, Wei-Tse; Li, Po-Chang; Fu, Tsu-Yi; Chang, Chia-Seng; Tsong, T. T.; Hwang, Ing-Shouh

2017-06-01

Focused ion beam (FIB) systems have become powerful diagnostic and modification tools for nanoscience and nanotechnology. Gas field ion sources (GFISs) built from atomic-size emitters offer the highest brightness among all ion sources and thus can improve the spatial resolution of FIB systems. Here we show that the Ir/W(111) single-atom tip (SAT) can emit high-brightness Xe+ ion beams with a high current stability. The ion emission current versus extraction voltage was analyzed from 150 K up to 309 K. The optimal emitter temperature for maximum Xe+ ion emission was ˜150 K and the reduced brightness at the Xe gas pressure of 1 × 10-4 torr is two to three orders of magnitude higher than that of a Ga liquid metal ion source, and four to five orders of magnitude higher than that of a Xe inductively coupled plasma ion source. Most surprisingly, the SAT emitter remained stable even when operated at 309 K. Even though the ion current decreased with increasing temperature, the current at room temperature (RT) could still reach over 1 pA when the gas pressure was higher than 1 × 10-3 torr, indicating the feasibility of RT-Xe-GFIS for application to FIB systems. The operation temperature of Xe-SAT-GFIS is considerably higher than the cryogenic temperature required for the helium ion microscope (HIM), which offers great technical advantages because only simple or no cooling schemes can be adopted. Thus, Xe-GFIS-FIB would be easy to implement and may become a powerful tool for nanoscale milling and secondary ion mass spectroscopy.

Enabling CD SEM metrology for 5nm technology node and beyond

NASA Astrophysics Data System (ADS)

Lorusso, Gian Francesco; Ohashi, Takeyoshi; Yamaguchi, Astuko; Inoue, Osamu; Sutani, Takumichi; Horiguchi, Naoto; Bömmels, Jürgen; Wilson, Christopher J.; Briggs, Basoene; Tan, Chi Lim; Raymaekers, Tom; Delhougne, Romain; Van den Bosch, Geert; Di Piazza, Luca; Kar, Gouri Sankar; Furnémont, Arnaud; Fantini, Andrea; Donadio, Gabriele Luca; Souriau, Laurent; Crotti, Davide; Yasin, Farrukh; Appeltans, Raf; Rao, Siddharth; De Simone, Danilo; Rincon Delgadillo, Paulina; Leray, Philippe; Charley, Anne-Laure; Zhou, Daisy; Veloso, Anabela; Collaert, Nadine; Hasumi, Kazuhisa; Koshihara, Shunsuke; Ikota, Masami; Okagawa, Yutaka; Ishimoto, Toru

2017-03-01

The CD SEM (Critical Dimension Scanning Electron Microscope) is one of the main tools used to estimate Critical Dimension (CD) in semiconductor manufacturing nowadays, but, as all metrology tools, it will face considerable challenges to keep up with the requirements of the future technology nodes. The root causes of these challenges are not uniquely related to the shrinking CD values, as one might expect, but to the increase in complexity of the devices in terms of morphology and chemical composition as well. In fact, complicated threedimensional device architectures, high aspect ratio features, and wide variety of materials are some of the unavoidable characteristics of the future metrology nodes. This means that, beside an improvement in resolution, it is critical to develop a CD SEM metrology capable of satisfying the specific needs of the devices of the nodes to come, needs that sometimes will have to be addressed through dramatic changes in approach with respect to traditional CD SEM metrology. In this paper, we report on the development of advanced CD SEM metrology at imec on a variety of device platform and processes, for both logic and memories. We discuss newly developed approaches for standard, IIIV, and germanium FinFETs (Fin Field Effect Transistors), for lateral and vertical nanowires (NW), 3D NAND (three-dimensional NAND), STT-MRAM (Spin Transfer Magnetic Torque Random-Access Memory), and ReRAM (Resistive Random Access Memory). Applications for both front-end of line (FEOL) and back-end of line (BEOL) are developed. In terms of process, S/D Epi (Source Drain Epitaxy), SAQP (Self-Aligned Quadruple Patterning), DSA (Dynamic Self-Assembly), and EUVL (Extreme Ultraviolet Lithography) have been used. The work reported here has been performed on Hitachi CG5000, CG6300, and CV5000. In terms of logic, we discuss here the S/D epi defect classification, the metrology optimization for STI (Shallow Trench Isolation) Ge FinFETs, the defectivity of III-V STI FinFETs,, metrology for vertical and horizontal NWs. With respect to memory, we discuss a STT-RAM statistical CD analysis and its comparison to electrical performance, ReRAM metrology for VMCO (Vacancy-modulated conductive oxide) with comparison with electrical performance, 3D NAND ONO (Oxide Nitride Oxide) thickness measurements. In addition, we report on 3D morphological reconstruction using CD SEM in conjunction with FIB (Focused Ion Beam), on optimized BKM (Best Known Methods) development methodologies, and on CD SEM overlay. The large variety of results reported here gives a clear overview of the creative effort put in place to ensure that the critical potential of CD SEM metrology tools is fully enabled for the 5nm node and beyond.

Dual Beam System (SEM/FIB) Equipment for the Kleberg Advanced Microscopy Center

DTIC Science & Technology

2015-06-05

Journal of Applied Physics (04 2015) John E. Sanchez, Ramón Díaz de León, Fernando Mendoza Santoyo, Gabriel González, Miguel José Yacaman, Arturo Ponce...includes PCs and cameras , will have available support for three years. What is Not Covered: This Warranty does not cover high-wear, consumable...110 x 110 mm eucentric stage - Multi-purpose holder - CCD IR camera - In-lens detectors: Lower (T1) and Upper (T2) - SE detector (ET-SED

Dislocation Content Measured Via 3D HR-EBSD Near a Grain Boundary in an AlCu Oligocrystal

NASA Technical Reports Server (NTRS)

Ruggles, Timothy; Hochhalter, Jacob; Homer, Eric

2016-01-01

Interactions between dislocations and grain boundaries are poorly understood and crucial to mesoscale plasticity modeling. Much of our understanding of dislocation-grain boundary interaction comes from atomistic simulations and TEM studies, both of which are extremely limited in scale. High angular resolution EBSD-based continuum dislocation microscopy provides a way of measuring dislocation activity at length scales and accuracies relevant to crystal plasticity, but it is limited as a two-dimensional technique, meaning the character of the grain boundary and the complete dislocation activity is difficult to recover. However, the commercialization of plasma FIB dual-beam microscopes have made 3D EBSD studies all the more feasible. The objective of this work is to apply high angular resolution cross correlation EBSD to a 3D EBSD data set collected by serial sectioning in a FIB to characterize dislocation interaction with a grain boundary. Three dimensional high angular resolution cross correlation EBSD analysis was applied to an AlCu oligocrystal to measure dislocation densities around a grain boundary. Distortion derivatives associated with the plasma FIB serial sectioning were higher than expected, possibly due to geometric uncertainty between layers. Future work will focus on mitigating the geometric uncertainty and examining more regions of interest along the grain boundary to glean information on dislocation-grain boundary interaction.

Comparing the detection of iron-based pottery pigment on a carbon-coated sherd by SEM-EDS and by Micro-XRF-SEM.

PubMed

Pendleton, Michael W; Washburn, Dorothy K; Ellis, E Ann; Pendleton, Bonnie B

2014-03-01

The same sherd was analyzed using a scanning electron microscope with energy dispersive spectroscopy (SEM-EDS) and a micro X-ray fluorescence tube attached to a scanning electron microscope (Micro-XRF-SEM) to compare the effectiveness of elemental detection of iron-based pigment. To enhance SEM-EDS mapping, the sherd was carbon coated. The carbon coating was not required to produce Micro-XRF-SEM maps but was applied to maintain an unbiased comparison between the systems. The Micro-XRF-SEM analysis was capable of lower limits of detection than that of the SEM-EDS system, and therefore the Micro-XRF-SEM system could produce elemental maps of elements not easily detected by SEM-EDS mapping systems. Because SEM-EDS and Micro-XRF-SEM have been used for imaging and chemical analysis of biological samples, this comparison of the detection systems should be useful to biologists, especially those involved in bone or tooth (hard tissue) analysis.

Comparing the Detection of Iron-Based Pottery Pigment on a Carbon-Coated Sherd by SEM-EDS and by Micro-XRF-SEM

PubMed Central

Pendleton, Michael W.; Washburn, Dorothy K.; Ellis, E. Ann; Pendleton, Bonnie B.

2014-01-01

The same sherd was analyzed using a scanning electron microscope with energy dispersive spectroscopy (SEM-EDS) and a micro X-ray fluorescence tube attached to a scanning electron microscope (Micro-XRF-SEM) to compare the effectiveness of elemental detection of iron-based pigment. To enhance SEM-EDS mapping, the sherd was carbon coated. The carbon coating was not required to produce Micro-XRF-SEM maps but was applied to maintain an unbiased comparison between the systems. The Micro-XRF-SEM analysis was capable of lower limits of detection than that of the SEM-EDS system, and therefore the Micro-XRF-SEM system could produce elemental maps of elements not easily detected by SEM-EDS mapping systems. Because SEM-EDS and Micro-XRF-SEM have been used for imaging and chemical analysis of biological samples, this comparison of the detection systems should be useful to biologists, especially those involved in bone or tooth (hard tissue) analysis. PMID:24600333

First evidence of tyre debris characterization at the nanoscale by focused ion beam

DOE Office of Scientific and Technical Information (OSTI.GOV)

Milani, M.; Pucillo, F.P.; Ballerini, M.

2004-07-15

In this paper, we present a novel technique for the nanoscale characterization of the outer and inner structure of tyre debris. Tyre debris is produced by the normal wear of tyres. In previous studies, the microcharacterization and identification were performed by analytical electron microscopy. This study is a development of the characterization of surface and microstructure of tyre debris. For the first time, tyre debris was analysed by focused ion beam (FIB), a technique with 2- to 5-nm resolution that does not require any sample preparation. We studied tyre debris produced in the laboratory. We made electron and ionic imagingmore » of the surface of the material, and after a ionic cut, we studied the internal microstructure of the same sample. The tyre debris was analysed by FIB without any sample preparations unlike the case of scanning and transmission electron microscopy (SEM and TEM). Useful information was derived to improve detection and monitoring techniques of pollution by tyre degradation processes.« less

RECENT DEVELOPMENT IN TEM CHARACTERIZATION OF IRRADIATED RERTR FUELS

DOE Office of Scientific and Technical Information (OSTI.GOV)

J. Gan; B.D. Miller; D.D. Keiser Jr.

2011-10-01

The recent development on TEM work of irradiated RERTR fuels includes microstructural characterization of the irradiated U-10Mo/alloy-6061 monolithic fuel plate, the RERTR-7 U-7Mo/Al-2Si and U-7Mo/Al-5Si dispersion fuel plates. It is the first time that a TEM sample of an irradiated nuclear fuel was prepared using the focused-ion-beam (FIB) lift-out technical at the Idaho National Laboratory. Multiple FIB TEM samples were prepared from the areas of interest in a SEM sample. The characterization was carried out using a 200kV TEM with a LaB6 filament. The three dimensional orderings of nanometer-sized fission gas bubbles are observed in the crystalline region of themore » U-Mo fuel. The co-existence of bubble superlattice and dislocations is evident. Detailed microstructural information along with composition analysis is obtained. The results and their implication on the performance of these fuels are discussed.« less

Electroless silver coating of rod-like glass particles.

PubMed

Moon, Jee Hyun; Kim, Kyung Hwan; Choi, Hyung Wook; Lee, Sang Wha; Park, Sang Joon

2008-09-01

An electroless silver coating of rod-like glass particles was performed and silver glass composite powders were prepared to impart electrical conductivity to these non-conducting glass particles. The low density Ag-coated glass particles may be utilized for manufacturing conducting inorganic materials for electromagnetic interference (EMI) shielding applications and the techniques for controlling the uniform thickness of silver coating can be employed in preparation of biosensor materials. For the surface pretreatment, Sn sensitization was performed and the coating powders were characterized by scanning electron microscopy (SEM), focused ion beam microscopy (FIB), and atomic force microscopy (AFM) along with the surface resistant measurements. In particular, the use of FIB technique for determining directly the Ag-coating thickness was very effective on obtaining the optimum conditions for coating. The surface sensitization and initial silver loading for electroless silver coating could be found and the uniform and smooth silver-coated layer with thickness of 46 nm was prepared at 2 mol/l of Sn and 20% silver loading.

M23C6 carbides and Cr2N nitrides in aged duplex stainless steel: A SEM, TEM and FIB tomography investigation.

PubMed

Maetz, J-Y; Douillard, T; Cazottes, S; Verdu, C; Kléber, X

2016-05-01

The precipitation evolution during ageing of a 2101 lean duplex stainless steel was investigated, revealing that the precipitate type and morphology depends on the nature of the grain boundary. Triangular M23C6 carbides precipitate only at γ/δ interfaces and rod-like Cr2N nitrides precipitate at both γ/δ and δ/δ interfaces. After 15min of ageing, the M23C6 size no longer evolves, whereas that of the Cr2N continues to evolve. For Cr2N, the morphology is maintained at γ/δ interfaces, whereas percolation occurs to form a continuous layer at δ/δ interfaces. By combining 2D and 3D characterisation at the nanoscale using transmission electron microscopy (TEM) and focused ion beam (FIB) tomography, a complete description of the precipitation evolution was obtained, including the composition, crystallographic structure, orientation relationship with the matrix phases, location, morphology, size and volume fraction. Copyright © 2016 Elsevier Ltd. All rights reserved.

Understanding the crack formation of graphite particles in cycled commercial lithium-ion batteries by focused ion beam - scanning electron microscopy

NASA Astrophysics Data System (ADS)

Lin, Na; Jia, Zhe; Wang, Zhihui; Zhao, Hui; Ai, Guo; Song, Xiangyun; Bai, Ying; Battaglia, Vincent; Sun, Chengdong; Qiao, Juan; Wu, Kai; Liu, Gao

2017-10-01

The structure degradation of commercial Lithium-ion battery (LIB) graphite anodes with different cycling numbers and charge rates was investigated by focused ion beam (FIB) and scanning electron microscopy (SEM). The cross-section image of graphite anode by FIB milling shows that cracks, resulted in the volume expansion of graphite electrode during long-term cycling, were formed in parallel with the current collector. The crack occurs in the bulk of graphite particles near the lithium insertion surface, which might derive from the stress induced during lithiation and de-lithiation cycles. Subsequently, crack takes place along grain boundaries of the polycrystalline graphite, but only in the direction parallel with the current collector. Furthermore, fast charge graphite electrodes are more prone to form cracks since the tensile strength of graphite is more likely to be surpassed at higher charge rates. Therefore, for LIBs long-term or high charge rate applications, the tensile strength of graphite anode should be taken into account.

PHOTOMICROPHOTOGRAPHY- GEOLOGY ( SEM)

NASA Image and Video Library

1972-10-13

PHOTOMICROPHOTOGRAPHY -GEOLOGY (SEM) High magnification and resolution views of lunar, meteorite and terrestrial materials using the Scanning Electron MIcroscope (SEM), Bldg. 31 Planetary and Earth Science Laboratory.

Morphology of the adult male and pupal exuviae of Glyptotendipes (Glyptotendipes) glaucus (Meigen 1818) (Diptera, Chironomidae) using scanning electron microscope (SEM).

PubMed

Kownacki, Andrzej; Woznicka, Olga; Szarek-Gwiazda, Ewa; Michailova, Paraskeva; Czaplicka, Anna

2017-02-27

In this paper, a study of the morphology of the pupa and male imago of Glyptotendipes (G.) glaucus (Meigen 1818) was carried out, with the aid of a scanning electron microscope (SEM). The SEM provided additional valuable information on the morphology of the species. Adult male head, antenna, wing, leg, abdomen, hypopygium, pupal cephalothorax and abdomen were examined. It is emphasized that SEM was not often used in Chironomidae studies. The present results confirm SEM as a suitable approach in carrying out morphological and taxonomical descriptions of Chironomidae species.

A Low Temperature Scanning Force Microscope with a Vertical Cantilever and Interferometric Detection Scheme

NASA Astrophysics Data System (ADS)

Kim, Jeehoon; Williams, T. L.; Chu, Sang Lin; Korre, Hasan; Chalfin, Max; Hoffman, J. E.

2008-03-01

We have developed a fiber-optic interferometry system with a vertical cantilever for scanning force microscopy. A lens, mounted on a Pan-type walker, was used to collect the interference signal in the cavity between the cantilever and the single mode fiber. This vertical geometry has several advantages: (1) it is directly sensitive to lateral forces; (2) low spring constant vertical cantilevers may allow increased force sensitivity by solving the ``snap-in'' problem that occurs with soft horizontal cantilevers. We have sharpened vertical cantilevers by focused ion beam (FIB), achieving a tip radius of 20 nm. We will show test results of a magnetic force microscope (MFM) with this vertical cantilever system.

CHARACTERISTICS OF INDIVIDUAL PARTICLES AT A RURAL SITE IN THE EASTERN UNITED STATES

EPA Science Inventory

To determine the nature of aerosol particles in a rural area of the eastern United States, aerosol samples were collected at Deep Creek Lake, Maryland, on various substrates and analyzed by a scanning electron microscope (SEM) and a transmission electron microscope (TEM). SEM ana...

Visualizing the 3D Architecture of Multiple Erythrocytes Infected with Plasmodium at Nanoscale by Focused Ion Beam-Scanning Electron Microscopy

PubMed Central

Soares Medeiros, Lia Carolina; De Souza, Wanderley; Jiao, Chengge; Barrabin, Hector; Miranda, Kildare

2012-01-01

Different methods for three-dimensional visualization of biological structures have been developed and extensively applied by different research groups. In the field of electron microscopy, a new technique that has emerged is the use of a focused ion beam and scanning electron microscopy for 3D reconstruction at nanoscale resolution. The higher extent of volume that can be reconstructed with this instrument represent one of the main benefits of this technique, which can provide statistically relevant 3D morphometrical data. As the life cycle of Plasmodium species is a process that involves several structurally complex developmental stages that are responsible for a series of modifications in the erythrocyte surface and cytoplasm, a high number of features within the parasites and the host cells has to be sampled for the correct interpretation of their 3D organization. Here, we used FIB-SEM to visualize the 3D architecture of multiple erythrocytes infected with Plasmodium chabaudi and analyzed their morphometrical parameters in a 3D space. We analyzed and quantified alterations on the host cells, such as the variety of shapes and sizes of their membrane profiles and parasite internal structures such as a polymorphic organization of hemoglobin-filled tubules. The results show the complex 3D organization of Plasmodium and infected erythrocyte, and demonstrate the contribution of FIB-SEM for the obtainment of statistical data for an accurate interpretation of complex biological structures. PMID:22432024

Development of scanning electron and x-ray microscope

DOE Office of Scientific and Technical Information (OSTI.GOV)

Matsumura, Tomokazu, E-mail: tomokzau.matsumura@etd.hpk.co.jp; Hirano, Tomohiko, E-mail: tomohiko.hirano@etd.hpk.co.jp; Suyama, Motohiro, E-mail: suyama@etd.hpk.co.jp

We have developed a new type of microscope possessing a unique feature of observing both scanning electron and X-ray images under one unit. Unlike former X-ray microscopes using SEM [1, 2], this scanning electron and X-ray (SELX) microscope has a sample in vacuum, thus it enables one to observe a surface structure of a sample by SEM mode, to search the region of interest, and to observe an X-ray image which transmits the region. For the X-ray observation, we have been focusing on the soft X-ray region from 280 eV to 3 keV to observe some bio samples and softmore » materials. The resolutions of SEM and X-ray modes are 50 nm and 100 nm, respectively, at the electron energy of 7 keV.« less

Morphology of the pore space in claystones - evidence from BIB/FIB ion beam sectioning and cryo-SEM observations

NASA Astrophysics Data System (ADS)

Desbois, G.; Urai, J. L.; Kukla, P. A.

2009-12-01

Mudrocks and clay-rich fault gouges are important mechanical elements in the Earth’s crust and form seals for crustal fluids such as groundwater and hydrocarbons. Other fields of interest are the storage of anthropogenic carbon dioxide and radioactive waste in geologic formations. In addition, coupled flows, capillary processes, and associated deformation are of importance in many applied fields. A key factor to understanding these processes is a detailed understanding of the morphology of the pore space. Classic studies of porosity in fine grained materials are performed on dried or freeze dried samples and include metal injection methods, magnetic susceptibility measurement, SEM and TEM imaging, neutron scattering, NMR spectroscopy, and ESEM. Confocal microscopy and X-ray tomography are used to image porosity in coarse grained sediments but the resolution of these techniques is not sufficient at present for applications to mudrocks or clay-rich fault gouges. Therefore, observations and interpretations remain difficult because none of these approaches is able to directly describe the in-situ porosity at the pore scale. In addition, some methods require dried samples in which the natural structure of pores may have been damaged to some extent due to desiccation and dehydration of the clay minerals. A recently developed alternative is to study wet samples using a cryo-SEM, which allows stabilization of wet media at cryo-temperature, in-situ sample preparation by ion beam cross-sectioning (BIB, FIB) and observations of the stabilized microstructure at high resolution. We report on a study of Boom clay from a proposed disposal site of radioactive waste (Mol site, Belgium) using cryo-SEM at cryogenic temperature, with ion beam cross-sectioning to prepare smooth, damage free surfaces. Pores commonly have crack-like tips, preferred orientation parallel to bedding and power law size distribution. We define a number of pore types depending on shape and location in the microstructure. 3-D reconstruction by serial cross-sectioning shows 3-D connectivity of the pore space. These findings offer a new insight into the morphology of pores down to nano-scale and provide the basis for microstructure-based models of transport in clays. SEM image (SE) of a Broad Ion Beam polished cross-section performed on dry Boom clay (Mol site, Belgium) showing the 2D apparent porosity (26.3%). The cross-section is perpendicular to the bedding.

The role of advanced reactive surface area characterization in improving predictions of mineral reaction rates

NASA Astrophysics Data System (ADS)

Beckingham, L. E.; Zhang, S.; Mitnick, E.; Cole, D. R.; Yang, L.; Anovitz, L. M.; Sheets, J.; Swift, A.; Kneafsey, T. J.; Landrot, G.; Mito, S.; Xue, Z.; Steefel, C. I.; DePaolo, D. J.; Ajo Franklin, J. B.

2014-12-01

Geologic sequestration of CO2 in deep sedimentary formations is a promising means of mitigating carbon emissions from coal-fired power plants but the long-term fate of injected CO2 is challenging to predict. Reactive transport models are used to gain insight over long times but rely on laboratory determined mineral reaction rates that have been difficult to extrapolate to field systems. This, in part, is due to a lack of understanding of mineral reactive surface area. Many models use an arbitrary approximation of reactive surface area, applying orders of magnitude scaling factors to measured BET or geometric surface areas. Recently, a few more sophisticated approaches have used 2D and 3D image analyses to determine mineral-specific reactive surface areas that account for the accessibility of minerals. However, the ability of these advanced surface area estimates to improve predictions of mineral reaction rates has yet to be determined. In this study, we fuse X-ray microCT, SEM QEMSCAN, XRD, SANS, and SEM-FIB analysis to determine mineral-specific accessible reactive surface areas for a core sample from the Nagaoka pilot CO2 injection site (Japan). This sample is primarily quartz, plagioclase, smectite, K-feldspar, and pyroxene. SEM imaging shows abundant smectite cement and grain coatings that decrease the fluid accessibility of other minerals. However, analysis of FIB-SEM images reveals that smectite nano-pores are well connected such that access to underlying minerals is not occluded by smectite coatings. Mineral-specific accessible surfaces are determined, accounting for the connectivity of the pore space with and without connected smectite nano-pores. The large-scale impact of variations in accessibility and dissolution rates are then determined through continuum scale modeling using grid-cell specific information on accessible surface areas. This approach will be compared with a traditional continuum scale model using mineral abundances and common surface area estimates. Ultimately, the effectiveness of advanced surface area characterization to improve mineral dissolution rates will be evaluated by comparison of model results with dissolution rates measured from a flow-through column experiment.

Search for Fluid Inclusions in a Carbonaceous Chondrite Using a New X-Ray Micro-Tomography Technique Combined with FIB Sampling

NASA Technical Reports Server (NTRS)

Tsuchiyama, A.; Miyake, A.; Zolensky, M. E.; Uesugi, K.; Nakano, T.; Takeuchi, A.; Suzuki, Y.; Yoshida, K.

2014-01-01

Early solar system aqueous fluids are preserved in some H chondrites as aqueous fluid inclusions in halite (e.g., [1]). Although potential fluid inclusions are also expected in carbonaceous chondrites [2], they have not been surely confirmed. In order to search for these fluid inclusions, we have developped a new X-ray micro-tomography technique combined with FIB sampling and applied this techniqu to a carbanaceous chondrite. Experimental: A polished thin section of Sutter's Mill meteorite (CM) was observed with an optical microscope and FE-SEM (JEOL 7001F) for chosing mineral grains of carbonates (mainly calcite) and sulfides (FeS and ZnS) 20-50 microns in typical size, which may have aqueous fluid inclusions. Then, a "house" similar to a cube with a roof (20-30 microns in size) is sampled from the mineral grain by using FIB (FEI Quanta 200 3DS). Then, the house was atached to a thin W-needle by FIB and imaged by a SR-based imaging microtomography system with a Fresnel zone plate at beamline BL47XU, SPring-8, Japan. One sample was imaged at two X-ray energies, 7 and 8 keV, to identify mineral phases (dual-enegy microtomography: [3]). The size of voxel (pixel in 3D) was 50-80 nm, which gave the effective spatial resolution of approx. 200 nm. A terrestrial quartz sample with an aqueous fluid inclusion with a bubble was also examined as a test sample by the same method. Results and discussion: A fluid inclusion of 5-8 microns in quartz was clearly identified in a CT image. A bubble of approx. 4 microns was also identified as refraction contrast although the X-ray absorption difference between fluid and bubble is small. Volumes of the fluid and bubble were obtained from the 3D CT images. Fourteen grains of calcite, two grains of iron sulfide and one grain of (Zn,Fe)S were examined. Ten calcite, one iron sulfide and one (Zn,Fe)S grains have inclusions >1 micron in size (the maximum: approx. 5 microns). The shapes are spherical or irregular. Tiny inclusions (<1 micron) are also present in all the grains examined. These results show that mineral grains have more inclusions than expected from 2D observations. The X-ray absorption of the inclusions shows that they are not solid inclusions. No bubbles were observed inside, indicating that we cannot determine whether they are really aqueous fluids or merely voids. One calcite grain has an inclusion approx. 2 microns in size, which seems to have a bubble and a tiny solid daughter crystal inside (three-phase inclusion). As we know the exact 3D position of the inclusion, we will anlyze the inclusion by SIMS after freezing the sample as has been done for a halite sample [3]. The present technique is useful for finding small inclusions not only in carbonaceous chondrites but also for terrestrial materials.

Surface effects on exciton diffusion in non polar ZnO/ZnMgO heterostructures

NASA Astrophysics Data System (ADS)

Sakr, G.; Sartel, C.; Sallet, V.; Lusson, A.; Patriarche, G.; Galtier, P.; Barjon, J.

2017-12-01

The diffusion of excitons injected in ZnO/Zn0.92Mg0.08O quantum well heterostructures grown by metal-organic-vapor-phase-epitaxy on non-polar ZnO substrates is investigated at room temperature. Cathodoluminescence linescans in a field-emission-gun scanning-electron-microscope are performed across cleaved cross-sections. A 55 nm diffusion length is assessed for excitons in bulk ZnMgO. When prepared as small angle bevels using focused ion beam (FIB), the effective diffusion length of excitons is shown to decrease down to 8 nm in the thinner part of the slab. This effect is attributed to non-radiative surface recombinations, with a 7  ×  104 cm s-1 recombination velocity estimated at the FIB-machined ZnMgO surface. The strong reduction of the diffusion extent in such thin lamellae usually used for transmission electron microscopy could be use improve the spatial resolution of cathodoluminescence images, often limited by diffusion processes.

Scanning Electron Microscopy (SEM) Procedure for HE Powders on a Zeiss Sigma HD VP SEM

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zaka, F.

This method describes the characterization of inert and HE materials by the Zeiss Sigma HD VP field emission Scanning Electron Microscope (SEM). The SEM uses an accelerated electron beam to generate high-magnification images of explosives and other materials. It is fitted with five detectors (SE, Inlens, STEM, VPSE, HDBSD) to enable imaging of the sample via different secondary electron signatures, angles, and energies. In addition to imaging through electron detection, the microscope is also fitted with two Oxford Instrument Energy Dispersive Spectrometer (EDS) 80 mm detectors to generate elemental constituent spectra and two-dimensional maps of the material being scanned.

3DSEM++: Adaptive and intelligent 3D SEM surface reconstruction.

PubMed

Tafti, Ahmad P; Holz, Jessica D; Baghaie, Ahmadreza; Owen, Heather A; He, Max M; Yu, Zeyun

2016-08-01

Structural analysis of microscopic objects is a longstanding topic in several scientific disciplines, such as biological, mechanical, and materials sciences. The scanning electron microscope (SEM), as a promising imaging equipment has been around for decades to determine the surface properties (e.g., compositions or geometries) of specimens by achieving increased magnification, contrast, and resolution greater than one nanometer. Whereas SEM micrographs still remain two-dimensional (2D), many research and educational questions truly require knowledge and facts about their three-dimensional (3D) structures. 3D surface reconstruction from SEM images leads to remarkable understanding of microscopic surfaces, allowing informative and qualitative visualization of the samples being investigated. In this contribution, we integrate several computational technologies including machine learning, contrario methodology, and epipolar geometry to design and develop a novel and efficient method called 3DSEM++ for multi-view 3D SEM surface reconstruction in an adaptive and intelligent fashion. The experiments which have been performed on real and synthetic data assert the approach is able to reach a significant precision to both SEM extrinsic calibration and its 3D surface modeling. Copyright © 2016 Elsevier Ltd. All rights reserved.

Localized Pulsed Electrodeposition Process for Three-Dimensional Printing of Nanotwinned Metallic Nanostructures.

PubMed

Daryadel, Soheil; Behroozfar, Ali; Morsali, S Reza; Moreno, Salvador; Baniasadi, Mahmoud; Bykova, Julia; Bernal, Rodrigo A; Minary-Jolandan, Majid

2018-01-10

Nanotwinned-metals (nt-metals) offer superior mechanical (high ductility and strength) and electrical (low electromigration) properties compared to their nanocrystalline (nc) counterparts. These properties are advantageous in particular for applications in nanoscale devices. However, fabrication of nt-metals has been limited to films (two-dimensional) or template-based (one-dimensional) geometries, using various chemical and physical processes. In this Letter, we demonstrate the ambient environment localized pulsed electrodeposition process for direct printing of three-dimensional (3D) freestanding nanotwinned-Copper (nt-Cu) nanostructures. 3D nt-Cu structures were additively manufactured using pulsed electrodeposition at the tip of an electrolyte-containing nozzle. Focused ion beam (FIB) and transmission electron microscopy (TEM) analysis revealed that the printed metal was fully dense, and was mostly devoid of impurities and microstructural defects. FIB and TEM images also revealed nanocrystalline-nanotwinned-microstructure (nc-nt-microstructure), and confirmed the formation of coherent twin boundaries in the 3D-printed Cu. Mechanical properties of the 3D-printed nc-nt-Cu were characterized by direct printing (FIB-less) of micropillars for in situ SEM microcompression experiments. The 3D-printed nc-nt-Cu exhibited a flow stress of over 960 MPa, among the highest ever reported, which is remarkable for a 3D-printed material. The microstructure and mechanical properties of the nc-nt-Cu were compared to those of nc-Cu printed using the same process under direct current (DC) voltage.

Demonstration of a focused ion-beam cross-sectioning technique for ultrastructural examination of resin-dentin interfaces.

PubMed

Van Meerbeek, B; Conn, L J; Duke, E S; Schraub, D; Ghafghaichi, F

1995-03-01

focused ion-beam (FIB) etching, commonly used as a cross-sectioning technique for failure analysis of semiconductor devices, has recently been applied to biological tissues to expose their ultrastructure for examination. It was the aim of this investigation to determine the practical utility of FIB to cross-section resin-dentin interfaces in order to morphologically evaluate the completeness of resin penetration into the exposed collagen scaffold at the resin-dentin bond interface. Two representative commercially available dentin adhesive systems were bonded to mid-coronal dentin. After appropriate fixation and dehydration of the resin-bonded dentin samples, a scanned focused ion-beam of a few tens of nano-meters in diameter was used to cross=section the resin-dentin interface. Examination of the interfacial ultrastructure was accomplished using a field-emission SEM. Results indicate possible artifact production at the cross-sectioned interface, hiding its actual ultrastructure, probably due to a heat-effect with possible recrystallization. Further studies of FIB are needed to optimize its usefulness for resin-dentin interface examinations and other biological tissue applications. Complete resin saturation of the demineralized dentin surface-layer has been claimed to be the key factor for a long-lasting resin-dentin bond. A "clean" artifact-free micro-cross-sectioning technique may provide indisputable ultra-structural information about the depth of resin penetration into the demineralized zone. Such a test would be useful in the development of dentin adhesive systems.

Characterizing the surface roughness of thermomechanical pulp fibers with atomic force microscopy

Treesearch

Rebecca Snell; Leslie H. Groom; Timothy G. Rials

2001-01-01

Loblolly pine, separated into mature and juvenile portions, was refined at various pressures (4, 8 and 12 bar). Fiber surfaces were investigated using a Scanning Electron Microscope (SEM) and an Atomic Force Microscope (AFM). Refiner pressure had a significant effect on the fiber surefaces. SEM images showed an apparent increase in surface roughness with increased...

Transmission Electron Microscope Studies of Martian 'Iddingsite' in the Nakhlite Meteorite MIL 090032

NASA Astrophysics Data System (ADS)

Hallis, L.; Ishii, H.; Bradley, J. P.; Taylor, J.

2012-12-01

As with the other nakhlites, MIL 090032 contains iddingsite-like alteration veins in the olivine phenocrysts that reportedly originated on Mars[1]. These 'iddingsite' veins have been analysed in a number of the nakhlite meteorites[2], and the presence of hydrous silicate gel, smectite clays, siderite, Fe-oxides, gypsum and carbonate have been reported. The presence and proportion of these phases in the different nakhlites appears to relate to the composition and concentration of the martian brine that flowed through each, thus supporting the theory that the nakhlite secondary alteration phases were produced by an evaporation sequence on the surface of Mars[3]. We analyzed these martian 'iddingsite' veins in MIL 090032 with the aim of placing it and its three paired meteorites within the nakhlite alteration sequence. By expanding our knowledge of this alteration sequence, we will gain extra insight into the conditions on the martian surface at the time these 'iddingsite' veins formed (<1.3 Ga). We utilized the 80-300 kV aberration-corrected FEI Titan (Scanning) Transmission Electron Microscope (S-TEM) system at Lawrence Livermore National Laboratory to analyse a ~15×8μm Focused Ion Beam (FIB) section of an 'iddingsite' vein in MIL 090032. To allow the electrons to be transmitted through the FIB section, it was milled down to ~150 nm thickness. Our initial TEM data indicate this FIB section contains hydrous amorphous silicate gel towards the center, with areas of phyllosilicate (possibly nontronite) interspersed within this central zone. Towards the outer edge of the vein jarosite and then gypsum sulfates were present. At the very edge only partially broken down olivine was observed. The presence of phyllosilicate and silicate gel in this vein suggests the 'iddingsite' in MIL 090032 was produced by water-rich brine, and the abundance of sulfates suggests the brine was enriched in sulfur. This assemblage of minerals is most in line with that of the 'iddingsite' veins in the meteorite Lafayette, which is thought to have been exposed to the most aqueous brine in the nakhlite alteration sequence[2,3]. MIL 090032 is a meteorite find, and contains areas of terrestrially derived sulfate-rich alteration which appear to have similar compositions to the martian 'iddingsite' veins (although texturally the two are easily distinguishable). Therefore, in addition to our analysis of the above 'iddignsite' FIB section, we aim to analyze a similar FIB section of this terrestrial sulfate-rich alteration and compare the two. This comparison could not only determine if terrestrial weathering has affected the mineralogy and petrology of the pre-terrestrial alteration, but also whether the conditions on the martian surface were similar to those in the Antarctic valleys at the time the 'iddingsite' veins formed. [1]Gooding et al. (1991) Meteoritics 26, 135-143. [2]Changela and Bridges (2011) MAPS 45, 1847-1867. [3]Bridges et al. (2001) Space Sci. Rev. 96, 365-392.

A brief discussion about image quality and SEM methods for quantitative fractography of polymer composites.

PubMed

Hein, L R O; Campos, K A; Caltabiano, P C R O; Kostov, K G

2013-01-01

The methodology for fracture analysis of polymeric composites with scanning electron microscopes (SEM) is still under discussion. Many authors prefer to use sputter coating with a conductive material instead of applying low-voltage (LV) or variable-pressure (VP) methods, which preserves the original surfaces. The present work examines the effects of sputter coating with 25 nm of gold on the topography of carbon-epoxy composites fracture surfaces, using an atomic force microscope. Also, the influence of SEM imaging parameters on fractal measurements is evaluated for the VP-SEM and LV-SEM methods. It was observed that topographic measurements were not significantly affected by the gold coating at tested scale. Moreover, changes on SEM setup leads to nonlinear outcome on texture parameters, such as fractal dimension and entropy values. For VP-SEM or LV-SEM, fractal dimension and entropy values did not present any evident relation with image quality parameters, but the resolution must be optimized with imaging setup, accompanied by charge neutralization. © Wiley Periodicals, Inc.

SD-SEM: sparse-dense correspondence for 3D reconstruction of microscopic samples.

PubMed

Baghaie, Ahmadreza; Tafti, Ahmad P; Owen, Heather A; D'Souza, Roshan M; Yu, Zeyun

2017-06-01

Scanning electron microscopy (SEM) imaging has been a principal component of many studies in biomedical, mechanical, and materials sciences since its emergence. Despite the high resolution of captured images, they remain two-dimensional (2D). In this work, a novel framework using sparse-dense correspondence is introduced and investigated for 3D reconstruction of stereo SEM images. SEM micrographs from microscopic samples are captured by tilting the specimen stage by a known angle. The pair of SEM micrographs is then rectified using sparse scale invariant feature transform (SIFT) features/descriptors and a contrario RANSAC for matching outlier removal to ensure a gross horizontal displacement between corresponding points. This is followed by dense correspondence estimation using dense SIFT descriptors and employing a factor graph representation of the energy minimization functional and loopy belief propagation (LBP) as means of optimization. Given the pixel-by-pixel correspondence and the tilt angle of the specimen stage during the acquisition of micrographs, depth can be recovered. Extensive tests reveal the strength of the proposed method for high-quality reconstruction of microscopic samples. Copyright © 2017 Elsevier Ltd. All rights reserved.

Evaluation of La0.6Sr0.4Co0.2Fe0.8O3-Gd0.1Ce0.9O1.95 composite cathode with three dimensional microstructure reconstruction

NASA Astrophysics Data System (ADS)

Kim, Y. T.; Jiao, Z.; Shikazono, N.

2017-02-01

In the present study, the polarization characteristics of La0.6Sr0.4Co0.2Fe0.8O3 (LSCF) - Gd0.1Ce0.9O1.95 (GDC) composite cathodes with different volume ratios were investigated. Samples with volume ratios of 20:80, 30:70, 50:50, 70:30 and 100:0 vol % were tested. The electrochemical impedance spectroscopy tests and current voltage curve measurements were carried out for the current densities from 0 to 0.2 Acm-2 with an interval of 0.05 Acm-2. The results showed that a volume ratio of LSCF:GDC = 30:70 composite cathode led to the lowest overpotential, and the overpotential increased in the order of 30:70, 50:50, 70:30, 100:0, 20:80 vol %. Three dimensional microstructures of composite cathodes were reconstructed and quantified by dual beam focused ion beam-scanning electron microscope (FIB-SEM). The results showed that neither LSCF surface area nor triple phase boundary (TPB) alone could explain the dependence of polarization characteristics on volume ratios. Current and electrochemical potential distributions were simulated by the Lattice Boltzmann method, in which both surface and TPB reactions were considered. Prediction considering both surface and TPB reactions could predict qualitatively the dependence of overpotentials on LSCF - GDC cathode composition.

Senescence-associated ultrastructural features of long-term cultures of induced pluripotent stem cells (iPSCs)

PubMed Central

Colasuonno, Fiorella; Borghi, Rossella; Niceforo, Alessia; Muzzi, Maurizio; Bertini, Enrico; Di Giulio, Andrea

2017-01-01

Induced pluripotent stem cells (iPSCs) hold great promise for developing personalized regenerative medicine, however characterization of their biological features is still incomplete. Moreover, changes occurring in long-term cultured iPSCs have been reported, suggesting these as a model of cellular aging. For this reason, we addressed the ultrastructural characterization of iPSCs, with a focus on possible time-dependent changes, involving specific cell compartments. To this aim, we comparatively analysed cultures at different timepoints, by an innovative electron microscopic technology (FIB/SEM). We observed progressive loss of cell-to-cell contacts, associated with increased occurrence of exosomes. Mitochondria gradually increased, while acquiring an elongated shape, with well-developed cristae. Such mitochondrial maturation was accompanied by their turnover, as assessed by the presence of autophagomes (undetectable in young iPSCs), some containing recognizable mitochondria. This finding was especially frequent in middle-aged iPSCs, while being occasional in aged cells, suggesting early autophagic activation followed by a decreased efficiency of the process with culturing time. Accordingly, confocal microscopy showed age-dependent alterations to the expression and distribution of autophagic markers. Interestingly, responsivity to rapamycin, highest in young iPSCs, was almost lost in aged cells. Overall, our results strongly support long-term cultured iPSCs as a model for studying relevant aspects of cellular senescence, involving intercellular communication, energy metabolism, and autophagy. PMID:29064821

Understanding the crack formation of graphite particles in cycled commercial lithium-ion batteries by focused ion beam - scanning electron microscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lin, Na; Jia, Zhe; Wang, Zhihui

Here in this paper, the structure degradation of commercial Lithium-ion battery (LIB) graphite anodes with different cycling numbers and charge rates was investigated by focused ion beam (FIB) and scanning electron microscopy (SEM). The cross-section image of graphite anode by FIB milling shows that cracks, resulted in the volume expansion of graphite electrode during long-term cycling, were formed in parallel with the current collector. The crack occurs in the bulk of graphite particles near the lithium insertion surface, which might derive from the stress induced during lithiation and de-lithiation cycles. Subsequently, crack takes place along grain boundaries of the polycrystallinemore » graphite, but only in the direction parallel with the current collector. Furthermore, fast charge graphite electrodes are more prone to form cracks since the tensile strength of graphite is more likely to be surpassed at higher charge rates. Therefore, for LIBs long-term or high charge rate applications, the tensile strength of graphite anode should be taken into account.« less

Understanding the crack formation of graphite particles in cycled commercial lithium-ion batteries by focused ion beam - scanning electron microscopy

DOE PAGES

Lin, Na; Jia, Zhe; Wang, Zhihui; ...

2017-10-01

Here in this paper, the structure degradation of commercial Lithium-ion battery (LIB) graphite anodes with different cycling numbers and charge rates was investigated by focused ion beam (FIB) and scanning electron microscopy (SEM). The cross-section image of graphite anode by FIB milling shows that cracks, resulted in the volume expansion of graphite electrode during long-term cycling, were formed in parallel with the current collector. The crack occurs in the bulk of graphite particles near the lithium insertion surface, which might derive from the stress induced during lithiation and de-lithiation cycles. Subsequently, crack takes place along grain boundaries of the polycrystallinemore » graphite, but only in the direction parallel with the current collector. Furthermore, fast charge graphite electrodes are more prone to form cracks since the tensile strength of graphite is more likely to be surpassed at higher charge rates. Therefore, for LIBs long-term or high charge rate applications, the tensile strength of graphite anode should be taken into account.« less

Revealing the cell-material interface with nanometer resolution by FIB-SEM

PubMed Central

Santoro, Francesca; Zhao, Wenting; Joubert, Lydia-Marie; Duan, Liting; Schnitker, Jan; van de Burgt, Yoeri; Lou, Hsin-Ya; Liu, Bofei; Salleo, Alberto; Cui, Lifeng; Cui, Yi; Cui, Bianxiao

2018-01-01

The interface between cells and non-biological surfaces regulates cell attachment, chronic tissue responses, and ultimately the success of medical implants or biosensors. Clinical and laboratory studies show that topological features of the surface profoundly influences cellular responses, e.g. titanium surfaces with nano- and microtopographical structures enhance osteoblast attachment and host-implant integration as compare to smooth surface. To understand how cells and tissues respond to different topographical features, it is of critical importance to directly visualize the cell-materials interface at the relevant nanometer length scale. Here, we present a new method for in situ examination of the cell-to-material interface at any desired location, based on focused-ion beam milling and scanning electron microscopy imaging (FIB-SEM) to resolve the cell membrane-to-material interface with 10 nm resolution. By examining how cell membranes interact with topographical features such as nanoscale protrusions or invaginations, we discovered that the cell membrane readily deforms inward and wraps around protruding structures, but hardly deforms outward to contour invaginating structures. This asymmetric membrane response (inward vs. outward deformation) causes the cleft width between the cell membrane and the nanostructure surface to vary for more than an order of magnitude. Our results suggest that surface topology is a crucial consideration for the development of medical implants or biosensors whose performances are strongly influenced by the cell-to-material interface. We anticipate that the method can be used to explore the direct interaction of cells/tissue with medical devices such as metal implants in the future. PMID:28682058

On the importance of FIB-SEM specific segmentation algorithms for porous media

DOE Office of Scientific and Technical Information (OSTI.GOV)

Salzer, Martin, E-mail: martin.salzer@uni-ulm.de; Thiele, Simon, E-mail: simon.thiele@imtek.uni-freiburg.de; Zengerle, Roland, E-mail: zengerle@imtek.uni-freiburg.de

2014-09-15

A new algorithmic approach to segmentation of highly porous three dimensional image data gained by focused ion beam tomography is described which extends the key-principle of local threshold backpropagation described in Salzer et al. (2012). The technique of focused ion beam tomography has shown to be capable of imaging the microstructure of functional materials. In order to perform a quantitative analysis on the corresponding microstructure a segmentation task needs to be performed. However, algorithmic segmentation of images obtained with focused ion beam tomography is a challenging problem for highly porous materials if filling the pore phase, e.g. with epoxy resin,more » is difficult. The gray intensities of individual voxels are not sufficient to determine the phase represented by them and usual thresholding methods are not applicable. We thus propose a new approach to segmentation that pays respect to the specifics of the imaging process of focused ion beam tomography. As an application of our approach, the segmentation of three dimensional images for a cathode material used in polymer electrolyte membrane fuel cells is discussed. We show that our approach preserves significantly more of the original nanostructure than a thresholding approach. - Highlights: • We describe a new approach to the segmentation of FIB-SEM images of porous media. • The first and last occurrences of structures are detected by analysing the z-profiles. • The algorithm is validated by comparing it to a manual segmentation. • The new approach shows significantly less artifacts than a thresholding approach. • A structural analysis also shows improved results for the obtained microstructure.« less

Effect of heterogeneity and shape on optical properties of urban dust based on three-dimensional modeling of individual particles

NASA Astrophysics Data System (ADS)

Conny, Joseph M.; Ortiz-Montalvo, Diana L.

2017-09-01

We show the effect of composition heterogeneity and shape on the optical properties of urban dust particles based on the three-dimensional spatial and optical modeling of individual particles. Using scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDX) and focused ion beam (FIB) tomography, spatial models of particles collected in Los Angeles and Seattle accounted for surface features, inclusions, and voids, as well as overall composition and shape. Using voxel data from the spatial models and the discrete dipole approximation method, we report extinction efficiency, asymmetry parameter, and single-scattering albedo (SSA). Test models of the particles involved (1) the particle's actual morphology as a single homogeneous phase and (2) simple geometric shapes (spheres, cubes, and tetrahedra) depicting composition homogeneity or heterogeneity (with multiple spheres). Test models were compared with a reference model, which included the particle's actual morphology and heterogeneity based on SEM/EDX and FIB tomography. Results show particle shape to be a more important factor for determining extinction efficiency than accounting for individual phases in a particle, regardless of whether absorption or scattering dominated. In addition to homogeneous models with the particles' actual morphology, tetrahedral geometric models provided better extinction accuracy than spherical or cubic models. For iron-containing heterogeneous particles, the asymmetry parameter and SSA varied with the composition of the iron-containing phase, even if the phase was <10% of the particle volume. For particles containing loosely held phases with widely varying refractive indexes (i.e., exhibiting "severe" heterogeneity), only models that account for heterogeneity may sufficiently determine SSA.

Visualizing Morphological Changes of Abscission Zone Cells in Arabidopsis by Scanning Electron Microscope.

PubMed

Shi, Chun-Lin; Butenko, Melinka A

2018-01-01

Scanning electron microscope (SEM) is a type of electron microscope which produces detailed images of surface structures. It has been widely used in plants and animals to study cellular structures. Here, we describe a detailed protocol to prepare samples of floral abscission zones (AZs) for SEM, as well as further image analysis. We show that it is a powerful tool to detect morphologic changes at the cellular level during the course of abscission in wild-type plants and to establish the details of phenotypic alteration in abscission mutants.

A Student-Built Scanning Tunneling Microscope

ERIC Educational Resources Information Center

Ekkens, Tom

2015-01-01

Many introductory and nanotechnology textbooks discuss the operation of various microscopes including atomic force (AFM), scanning tunneling (STM), and scanning electron microscopes (SEM). In a nanotechnology laboratory class, students frequently utilize microscopes to obtain data without a thought about the detailed operation of the tool itself.…

Nondestructive SEM for surface and subsurface wafer imaging

NASA Technical Reports Server (NTRS)

Propst, Roy H.; Bagnell, C. Robert; Cole, Edward I., Jr.; Davies, Brian G.; Dibianca, Frank A.; Johnson, Darryl G.; Oxford, William V.; Smith, Craig A.

1987-01-01

The scanning electron microscope (SEM) is considered as a tool for both failure analysis as well as device characterization. A survey is made of various operational SEM modes and their applicability to image processing methods on semiconductor devices.

Scanning electron microscope image signal-to-noise ratio monitoring for micro-nanomanipulation.

PubMed

Marturi, Naresh; Dembélé, Sounkalo; Piat, Nadine

2014-01-01

As an imaging system, scanning electron microscope (SEM) performs an important role in autonomous micro-nanomanipulation applications. When it comes to the sub micrometer range and at high scanning speeds, the images produced by the SEM are noisy and need to be evaluated or corrected beforehand. In this article, the quality of images produced by a tungsten gun SEM has been evaluated by quantifying the level of image signal-to-noise ratio (SNR). In order to determine the SNR, an efficient and online monitoring method is developed based on the nonlinear filtering using a single image. Using this method, the quality of images produced by a tungsten gun SEM is monitored at different experimental conditions. The derived results demonstrate the developed method's efficiency in SNR quantification and illustrate the imaging quality evolution in SEM. © 2014 Wiley Periodicals, Inc.

Three-Dimensional (3D) Nanometrology Based on Scanning Electron Microscope (SEM) Stereophotogrammetry.

PubMed

Tondare, Vipin N; Villarrubia, John S; Vlada R, András E

2017-10-01

Three-dimensional (3D) reconstruction of a sample surface from scanning electron microscope (SEM) images taken at two perspectives has been known for decades. Nowadays, there exist several commercially available stereophotogrammetry software packages. For testing these software packages, in this study we used Monte Carlo simulated SEM images of virtual samples. A virtual sample is a model in a computer, and its true dimensions are known exactly, which is impossible for real SEM samples due to measurement uncertainty. The simulated SEM images can be used for algorithm testing, development, and validation. We tested two stereophotogrammetry software packages and compared their reconstructed 3D models with the known geometry of the virtual samples used to create the simulated SEM images. Both packages performed relatively well with simulated SEM images of a sample with a rough surface. However, in a sample containing nearly uniform and therefore low-contrast zones, the height reconstruction error was ≈46%. The present stereophotogrammetry software packages need further improvement before they can be used reliably with SEM images with uniform zones.

Towards metal chalcogenide nanowire-based colour-sensitive photodetectors

NASA Astrophysics Data System (ADS)

Butanovs, Edgars; Butikova, Jelena; Zolotarjovs, Aleksejs; Polyakov, Boris

2018-01-01

In recent years, nanowires have been shown to exhibit high photosensitivities, and, therefore are of interest in a variety of optoelectronic applications, for example, colour-sensitive photodetectors. In this study, we fabricated two-terminal PbS, In2S3, CdS and ZnSe single-nanowire photoresistor devices and tested applicability of these materials under the same conditions for colour-sensitive (405 nm, 532 nm and 660 nm) light detection. Nanowires were grown via atmospheric pressure chemical vapour transport method, their structure and morphology were characterized by scanning and transmission electron microscopy (SEM and TEM), X-ray diffraction (XRD), and optical properties were investigated with photoluminescence (PL) measurements. Single-nanowire photoresistors were fabricated via in situ nanomanipulations inside SEM, using focused ion beam (FIB) cutting and electron-beam-assisted platinum welding; their current-voltage characteristics and photoresponse values were measured. Applicability of the tested nanowire materials for colour-sensitive light detection is discussed.

Study of nanoscale structural biology using advanced particle beam microscopy

NASA Astrophysics Data System (ADS)

Boseman, Adam J.

This work investigates developmental and structural biology at the nanoscale using current advancements in particle beam microscopy. Typically the examination of micro- and nanoscale features is performed using scanning electron microscopy (SEM), but in order to decrease surface charging, and increase resolution, an obscuring conductive layer is applied to the sample surface. As magnification increases, this layer begins to limit the ability to identify nanoscale surface structures. A new technology, Helium Ion Microscopy (HIM), is used to examine uncoated surface structures on the cuticle of wild type and mutant fruit flies. Corneal nanostructures observed with HIM are further investigated by FIB/SEM to provide detailed three dimensional information about internal events occurring during early structural development. These techniques are also used to reconstruct a mosquito germarium in order to characterize unknown events in early oogenesis. Findings from these studies, and many more like them, will soon unravel many of the mysteries surrounding the world of developmental biology.

Micro- and nano-scale damage on the surface of W divertor component during exposure to high heat flux loads with He

NASA Astrophysics Data System (ADS)

Li, C.; Greuner, H.; Zhao, S. X.; Böswirth, B.; Luo, G. N.; Zhou, X.; Jia, Y. Z.; Liu, X.; Liu, W.

2015-11-01

Micro- and nano-scale surface damage on a W divertor component sample exposed to high heat flux loads generated with He atoms has been investigated through SEM, EBSD, AFM and FIB-SEM. The component sample was supplied by the Institute of Plasma Physics, Chinese Academy of Sciences (ASIPP) and AT&M company, China, and the loading experiment was performed in the GLADIS facility at IPP Garching, Germany. Two typical damage structures were observed on the surface: the first one is characterized by obvious blisters and some grooves formed from ruptured blisters, and the other one is a kind of porous structure accompanying with at least ∼25 nm surface material loss. As the grain orientation is further away from <111>, the damage morphology gradually changes from the former structure to the latter. The possible damage mechanism is discussed.

The Scanning Electron Microscope As An Accelerator For The Undergraduate Advanced Physics Laboratory

NASA Astrophysics Data System (ADS)

Peterson, Randolph S.; Berggren, Karl K.; Mondol, Mark

2011-06-01

Few universities or colleges have an accelerator for use with advanced physics laboratories, but many of these institutions have a scanning electron microscope (SEM) on site, often in the biology department. As an accelerator for the undergraduate, advanced physics laboratory, the SEM is an excellent substitute for an ion accelerator. Although there are no nuclear physics experiments that can be performed with a typical 30 kV SEM, there is an opportunity for experimental work on accelerator physics, atomic physics, electron-solid interactions, and the basics of modern e-beam lithography.

Rapid fibroblast activation in mammalian cells induced by silicon nanowire arrays

NASA Astrophysics Data System (ADS)

Ha, Qing; Yang, Gao; Ao, Zhuo; Han, Dong; Niu, Fenglan; Wang, Shutao

2014-06-01

Activated tumor-associated fibroblasts (TAFs) with abundant fibroblast activation protein (FAP) expression attract tremendous attention in tumor progression studies. In this work, we report a rapid 24 h FAP activation method for fibroblasts using silicon nanowires (SiNWs) as culture substrates instead of growth factors or chemokines. In contrast with cells cultured on flat silicon which rarely express FAP, SiNW cultivated cells exhibit FAP levels similar to those found in cancerous tissue. We demonstrated that activated cells grown on SiNWs maintain their viability and proliferation in a time-dependent manner. Moreover, environmental scanning electron microscopy (ESEM) and focused ion beam and scanning electron microscopy (FIB-SEM) analysis clearly revealed that activated cells on SiNWs adapt to the structure of their substrates by filling inter-wire cavities via filopodia in contrast to cells cultured on flat silicon which spread freely. We further illustrated that the expression of FAP was rarely detected in activated cells after being re-cultured in Petri dishes, suggesting that the unique structure of SiNWs may have a certain influence on FAP activation.Activated tumor-associated fibroblasts (TAFs) with abundant fibroblast activation protein (FAP) expression attract tremendous attention in tumor progression studies. In this work, we report a rapid 24 h FAP activation method for fibroblasts using silicon nanowires (SiNWs) as culture substrates instead of growth factors or chemokines. In contrast with cells cultured on flat silicon which rarely express FAP, SiNW cultivated cells exhibit FAP levels similar to those found in cancerous tissue. We demonstrated that activated cells grown on SiNWs maintain their viability and proliferation in a time-dependent manner. Moreover, environmental scanning electron microscopy (ESEM) and focused ion beam and scanning electron microscopy (FIB-SEM) analysis clearly revealed that activated cells on SiNWs adapt to the structure of their substrates by filling inter-wire cavities via filopodia in contrast to cells cultured on flat silicon which spread freely. We further illustrated that the expression of FAP was rarely detected in activated cells after being re-cultured in Petri dishes, suggesting that the unique structure of SiNWs may have a certain influence on FAP activation. Electronic supplementary information (ESI) available: (1) ESEM cross-sectional view images of the flat silicon and SiNW substrates. (2) Bright field morphology images of fibroblasts cultured in Petri dishes. (3) FIB/SEM 52° tilt images of fibroblasts cultured on SiNW 2 and SiNW 3. (4) Immunofluorescence images of FAP expression in fibroblasts re-cultured in Petri dishes after detachment from flat silicon and a series of SiNW substrates. (5) ESEM images of cells re-cultured in Petri dishes after detachment from each group. See DOI: 10.1039/c4nr01415d

Fibrinogen deficiency suppresses the development of early and delayed radiation enteropathy

PubMed Central

Wang, Junru; Pathak, Rupak; Garg, Sarita; Hauer-Jensen, Martin

2017-01-01

AIM To determine the mechanistic role of fibrinogen, a key regulator of inflammation and fibrosis, in early and delayed radiation enteropathy. METHODS Fibrinogen wild-type (Fib+/+), fibrinogen heterozygous (Fib+/-), and fibrinogen knockout (Fib-/-) mice were exposed to localized intestinal irradiation and assessed for early and delayed structural changes in the intestinal tissue. A 5-cm segment of ileum of mice was exteriorized and exposed to 18.5 Gy of x-irradiation. Intestinal tissue injury was assessed by quantitative histology, morphometry, and immunohistochemistry at 2 wk and 26 wk after radiation. Plasma fibrinogen level was measured by enzyme-linked immunosorbent assay. RESULTS There was no difference between sham-irradiated Fib+/+ and Fib+/- mice in terms of fibrinogen concentration in plasma and intestinal tissue, intestinal histology, morphometry, intestinal smooth muscle cell proliferation, and neutrophil infiltration. Therefore, Fib+/- mice were used as littermate controls. Unlike sham-irradiated Fib+/+ and Fib+/- mice, no fibrinogen was detected in the plasma and intestinal tissue of sham-irradiated Fib-/- mice. Moreover, fibrinogen level was not elevated after irradiation in the intestinal tissue of Fib-/- mice, while significant increase in intestinal fibrinogen level was noticed in irradiated Fib+/+ and Fib+/- mice. Importantly, irradiated Fib-/- mice exhibited substantially less overall intestinal structural injury (RIS, P = 0.000002), intestinal wall thickness (P = 0.003), intestinal serosal thickness (P = 0.009), collagen deposition (P = 0.01), TGF-β immunoreactivity (P = 0.03), intestinal smooth muscle proliferation (P = 0.046), neutrophil infiltration (P = 0.01), and intestinal mucosal injury (P = 0.0003), compared to irradiated Fib+/+ and Fib+/- mice at both 2 wk and 26 wk. CONCLUSION These data demonstrate that fibrinogen deficiency directly attenuates development of early and delayed radiation enteropathy. Fibrinogen could be a novel target in treating intestinal damage. PMID:28765691

Formation of the YBa2Cu2NbOy Phase in Thin Films (POSTPRINT)

DTIC Science & Technology

2010-03-01

protective layer was deposited on the top of YBCNO film by dc sputtering . A 200 nm 200 nm area film was selected and cut with a Ga ion beam (30 kV...200 TEM at 200 kV. Samples for TEM were prepared using a focused ion beam (FIB (Eindhoven, The Netherlands)) microscope. For TEM examination, a thin Pt...by dc magnetron sputtering deposition of Ag with 93 mm thickness. Transport current measurements were made in liquid nitrogen with the 4-probe method

Prognostic value of combined preoperative fibrinogen and neutrophil–lymphocyte ratio in patients with hepatocellular carcinoma after liver transplantation

PubMed Central

Chen, Mao-Gen; Wang, Xiao-Ping; Ju, Wei-Qiang; Zhao, Qiang; Wu, Lin-Wei; Ren, Qing-Qi; Guo, Zhi-Yong; Wang, Dong-Ping; Zhu, Xiao-Feng; Ma, Yi; He, Xiao-Shun

2017-01-01

Objectives Elevated plasma fibrinogen (Fib) correlated with patient's prognosis in several solid tumors. However, few studies have illuminated the relationship between preoperative Fib and prognosis of HCC after liver transplantation. We aimed to clarify the prognostic value of Fib and whether the prognostic accuracy can be enhanced by the combination of Fib and neutrophil–lymphocyte ratio (NLR). Results Fib was correlated with Child-pugh stage, alpha-fetoprotein (AFP), size of largest tumor, macro- and micro-vascular invasion. Univariate analysis showed preoperative Fib, AFP, NLR, size of largest tumor, tumor number, macro- and micro- vascular invasion were significantly associated with disease-free survival (DFS) and overall survival (OS) in HCC patients with liver transplantation. After multivariate analysis, only Fib and macro-vascular invasion were independently correlated with DFS and OS. Survival analysis showed that preoperative Fib > 2.345 g/L predicted poor prognosis of patients HCC after liver transplantation. Preoperative Fib showed prognostic value in various subgroups of HCC. Furthermore, the predictive range was expanded by the combination of Fib and NLR. Materials and Methods Data were collected retrospectively from 130 HCC patients who underwent liver transplantation. Preoperative Fib, NLR and clinicopathologic variables were analyzed. The survival analysis was performed by the Kaplan-Meier method, and compared by the log-rank test. Univariate and multivariate analyses were performed to identify the prognostic factors for DFS and OS. Conclusions Preoperative Fib is an independent effective predictor of prognosis for HCC patients, higher levels of Fib predict poorer outcomes and the combination of Fib and NLR enlarges the prognostic accuracy of testing. PMID:27935864

A Miniaturized Variable Pressure Scanning Electron Microscope (MVP-SEM) for the Surface of Mars: An Instrument for the Planetary Science Community

NASA Technical Reports Server (NTRS)

Edmunson, J.; Gaskin, J. A.; Danilatos, G.; Doloboff, I. J.; Effinger, M. R.; Harvey, R. P.; Jerman, G. A.; Klein-Schoder, R.; Mackie, W.; Magera, B.;

Surface characteristics of isopod digestive gland epithelium studied by SEM.

PubMed

Millaku, Agron; Leser, Vladka; Drobne, Damjana; Godec, Matjaz; Torkar, Matjaz; Jenko, Monika; Milani, Marziale; Tatti, Francesco

2010-05-01

The structure of the digestive gland epithelium of a terrestrial isopod Porcellio scaber has been investigated by conventional scanning electron microscopy (SEM), focused ion beam-scanning electron microscopy (FIB/SEM), and light microscopy in order to provide evidence on morphology of the gland epithelial surface in animals from a stock culture. We investigated the shape of cells, extrusion of lipid droplets, shape and distribution of microvilli, and the presence of bacteria on the cell surface. A total of 22 animals were investigated and we found some variability in the appearance of the gland epithelial surface. Seventeen of the animals had dome-shaped digestive gland "normal" epithelial cells, which were densely and homogeneously covered by microvilli and varying proportions of which extruded lipid droplets. On the surface of microvilli we routinely observed sparsely distributed bacteria of different shapes. Five of the 22 animals had "abnormal" epithelial cells with a significantly altered shape. In three of these animals, the cells were much smaller, partly or completely flat or sometimes pyramid-like. A thick layer of bacteria was detected on the microvillous border, and in places, the shape and size of microvilli were altered. In two animals, hypertrophic cells containing large vacuoles were observed indicating a characteristic intracellular infection. The potential of SEM in morphological investigations of epithelial surfaces is discussed.

The Potential Protective Effects of 2-aminoethyl Diphenylborinate against Inner Ear Acoustic Trauma: Experimental Study Using Transmission and Scanning Electron Microscopy.

PubMed

Kaymakçı, Mustafa; Acar, Mustafa; Burukoglu, Dilek; Kutlu, Hatice Mehtap; Shojaolsadati, Paria; Cingi, Cemal; Bayar Muluk, Nuray

2015-04-01

In this prospective experimental study, we investigated the preventive effects of 2-aminoethyl diphenylborinate (2-APB) in rats exposed to acoustic trauma (AT). Light microscopic, transmission electron microscopic (TEM), and scanning electron microscopic (SEM) examinations were performed. Eighteen healthy Wistar albino rats were divided into the following three groups: groups 1 (control), 2 (AT), and 3 (AT+APB). The rats in groups 2 and 3 were exposed to AT; in group 3 rats, 2-APB at 2 mg/kg was also administered, initially transperitoneally, after 10 min. During the light microscopic, TEM, and SEM examinations, the structures of the cochlear hair cells, stereocilia, and Deiter's cells were normal in the control group. In the AT group, the organ of Corti and proximate structures were damaged according to the light microscopic examination. During the TEM examination, intense cellular damage and stereocilia loss were detected, while during the SEM examination, extensive damage and stereocilia loss were observed. Decreased damage with preserved cochlear structure was detected during the light microscopic examination in the AT+APB group than in the AT group. During the TEM and SEM examinations, although stereocilia loss occurred in the AT+APB group, near-normal cell, cilia, and tectorial membrane structures were also observed in the AT+APB group compared with the AT group. 2-APB may have protective effects against AT damage of the cochlea. The main mechanism underlying this effect is the inhibition of the vasoconstriction of the cochlear spiral modiolar artery, thereby improving cochlear blood flow. We conclude that 2-APB may also be effective if used immediately following AT.

Scanning Electron Microscope-Cathodoluminescence Analysis of Rare-Earth Elements in Magnets.

PubMed

Imashuku, Susumu; Wagatsuma, Kazuaki; Kawai, Jun

2016-02-01

Scanning electron microscope-cathodoluminescence (SEM-CL) analysis was performed for neodymium-iron-boron (NdFeB) and samarium-cobalt (Sm-Co) magnets to analyze the rare-earth elements present in the magnets. We examined the advantages of SEM-CL analysis over conventional analytical methods such as SEM-energy-dispersive X-ray (EDX) spectroscopy and SEM-wavelength-dispersive X-ray (WDX) spectroscopy for elemental analysis of rare-earth elements in NdFeB magnets. Luminescence spectra of chloride compounds of elements in the magnets were measured by the SEM-CL method. Chloride compounds were obtained by the dropwise addition of hydrochloric acid on the magnets followed by drying in vacuum. Neodymium, praseodymium, terbium, and dysprosium were separately detected in the NdFeB magnets, and samarium was detected in the Sm-Co magnet by the SEM-CL method. In contrast, it was difficult to distinguish terbium and dysprosium in the NdFeB magnet with a dysprosium concentration of 1.05 wt% by conventional SEM-EDX analysis. Terbium with a concentration of 0.02 wt% in an NdFeB magnet was detected by SEM-CL analysis, but not by conventional SEM-WDX analysis. SEM-CL analysis is advantageous over conventional SEM-EDX and SEM-WDX analyses for detecting trace rare-earth elements in NdFeB magnets, particularly dysprosium and terbium.

Freeze-fracture of infected plant leaves in ethanol for scanning electron microscopic study of fungal pathogens.

PubMed

Moore, Jayma A; Payne, Scott A

2012-01-01

Fungi often are found within plant tissues where they cannot be visualized with the scanning electron microscope (SEM). We present a simple way to reveal cell interiors while avoiding many common causes of artifact. Freeze-fracture of leaf tissue using liquid nitrogen during the 100% ethanol step of the dehydration process just before critical point drying is useful in exposing intracellular fungi to the SEM.

Nonlinear least squares regression for single image scanning electron microscope signal-to-noise ratio estimation.

PubMed

Sim, K S; Norhisham, S

2016-11-01

A new method based on nonlinear least squares regression (NLLSR) is formulated to estimate signal-to-noise ratio (SNR) of scanning electron microscope (SEM) images. The estimation of SNR value based on NLLSR method is compared with the three existing methods of nearest neighbourhood, first-order interpolation and the combination of both nearest neighbourhood and first-order interpolation. Samples of SEM images with different textures, contrasts and edges were used to test the performance of NLLSR method in estimating the SNR values of the SEM images. It is shown that the NLLSR method is able to produce better estimation accuracy as compared to the other three existing methods. According to the SNR results obtained from the experiment, the NLLSR method is able to produce approximately less than 1% of SNR error difference as compared to the other three existing methods. © 2016 The Authors Journal of Microscopy © 2016 Royal Microscopical Society.

Scanning electron microscope cathodoluminescence imaging of subgrain boundaries, twins and planar deformation features in quartz

NASA Astrophysics Data System (ADS)

Hamers, M. F.; Pennock, G. M.; Drury, M. R.

2017-04-01

The study of deformation features has been of great importance to determine deformation mechanisms in quartz. Relevant microstructures in both growth and deformation processes include dislocations, subgrains, subgrain boundaries, Brazil and Dauphiné twins and planar deformation features (PDFs). Dislocations and twin boundaries are most commonly imaged using a transmission electron microscope (TEM), because these cannot directly be observed using light microscopy, in contrast to PDFs. Here, we show that red-filtered cathodoluminescence imaging in a scanning electron microscope (SEM) is a useful method to visualise subgrain boundaries, Brazil and Dauphiné twin boundaries. Because standard petrographic thin sections can be studied in the SEM, the observed structures can be directly and easily correlated to light microscopy studies. In contrast to TEM preparation methods, SEM techniques are non-destructive to the area of interest on a petrographic thin section.

Characterization of the multilayered shell of a limpet, Lottia kogamogai (Mollusca: Patellogastropoda), using SEM-EBSD and FIB-TEM techniques.

PubMed

Suzuki, Michio; Kameda, Jun; Sasaki, Takenori; Saruwatari, Kazuko; Nagasawa, Hiromichi; Kogure, Toshihiro

2010-08-01

The microstructure and its crystallographic aspect of the shell of a limpet, Lottiakogamogai, have been investigated, as the first step to clarify the mechanism of shell formation in limpet. The shell consists of five distinct layers stacked along the shell thickness direction. Transmission electron microscopy (TEM) with the focused ion beam (FIB) sample preparation technique was primarily adopted, as well as scanning electron microscopy (SEM) with electron back-scattered diffraction (EBSD). The five layers were termed as M+3, M+2, M+1, M, M-1 from the outside to the inside in previous works, where M means myostracum. The outmost M+3 layer consists of calcite with a "mosaic" structure; granular submicron sub-grains with small-angle grain boundaries often accompanying dislocation arrays. M+2 layer consists of flat prismatic aragonite crystals with a leaf-like cross section, stacked obliquely to the shell surface. It looks that the prismatic crystals are surrounded by organic sheets, forming a compartment structure. M+1 and M-1 layers adopt a crossed lamellar structure consisting of aragonite flat prisms with rectangular cross section. M layer has a prismatic structure of aragonite perpendicular to the shell surface and with irregular shaped cross sections. Distinct organic sheets were not observed between the crystals in M+1, M and M-1 layers. The {110} twins are common in all aragonite M+2, M+1, M and M-1 layers, with the twin boundaries parallel to the prisms. These results for the microstructure of each layer should be considered in the discussion of the formation mechanism of the limpet shell structure. Copyright 2010 Elsevier Inc. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kruska, Karen; Zhai, Ziqing; Bruemmer, Stephen M.

Due to its superior resistance to corrosion and stress corrosion cracking (SCC), high Cr, Ni-base Alloy 690 is now commonly used in pressurized water reactors (PWRs). Even though highly cold-worked (CW) Alloy 690 has been shown to be susceptible to SCC crack growth in PWR primary water environments, an open question remains whether SCC initiation was possible for these materials under constant load test conditions. Testing has been performed on a series of CW alloy 690 CRDM tubing specimens at constant load for up to 9,220 hours in 360°C simulated PWR primary water. A companion paper will discuss the overallmore » testing approach and describe results on different alloy 690 heats and cold work levels. The focus of the current paper is to illustrate the use of focused ion beam (FIB), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) for the high-resolution investigation of precursor damage and intergranular (IG) crack nucleation in these specimens. Three-dimensional (3D) FIB/SEM imaging has been conducted on a series of grain boundary (GB) damage precursors, such as IG small cavities, local corrosion and even shallow cracks observed at the specimen surface. Contrast variations and EDS mapping were used to distinguish oxides, carbides and cavities from the matrix material. Nanometer-sized cavities were observed associated with GB carbides in the highly CW specimens. Shallow IG cracks were present in the 30%CW specimens and exhibited oxidized crack flanks and a higher density of cavities ahead of the oxide front in all cases. The shape and distribution of carbides and cavities in the plane of the cracked GBs was analyzed in 3D to gain a mechanistic understanding of the processes that may be leading to crack initiation in highly CW alloy 690.« less

A simple bedside blood test (Fibrofast; FIB-5) is superior to FIB-4 index for the differentiation between non-significant and significant fibrosis in patients with chronic hepatitis C.

PubMed

Shiha, G; Seif, S; Eldesoky, A; Elbasiony, M; Soliman, R; Metwally, A; Zalata, K; Mikhail, N

2017-05-01

A simple non-invasive score (Fibrofast, FIB-5) was developed using five routine laboratory tests (ALT, AST, alkaline phosphatase, albumin and platelets count) for the detection of significant hepatic fibrosis in patients with chronic hepatitis C. The FIB-4 index is a non-invasive test for the assessment of liver fibrosis, and a score of ≤1.45 enables the correct identification of patients who have non-significant (F0-1) from significant fibrosis (F2-4), and could avoid liver biopsy. The aim of this study was to compare the performance characteristics of FIB-5 and FIB-4 to differentiate between non-significant and significant fibrosis. A cross-sectional study included 604 chronic HCV patients. All liver biopsies were scored using the METAVIR system. Both FIB-5 and FIB-4 scores were measured and the performance characteristics were calculated using the ROC curve. The performance characteristics of FIB-5 at ≥7.5 and FIB-4 at ≤1.45 for the differentiation between non-significant fibrosis and significant fibrosis were: specificity 94.4%, PPV 85.7%, and specificity 54.9%, PPV 55.7% respectively. FIB-5 score at the new cutoff is superior to FIB-4 index for the differentiation between non-significant and significant fibrosis.

Size determination of Acipenser ruthenus spermatozoa in different types of electron microscopy.

PubMed

Psenicka, Martin; Tesarová, Martina; Tesitel, Jakub; Nebesárová, Jana

2010-07-01

In this study three types of scanning electron microscopes were used for the size determination of spermatozoa of sterlet Acipenser ruthenus - high vacuum scanning electron microscope (SEM, JEOL 6300), environmental scanning electron microscope (ESEM, Quanta 200 FEG), field emission scanning electron microscope (FESEM, JEOL 7401F) with cryoattachment Alto 2500 (Gatan) and transmission electron microscope (TEM, JEOL 1010). The use of particular microscopes was tied with different specimen preparation techniques. The aim of this study was to evaluate to what degree the type of used electron microscope can influence the size of different parts of spermatozoa. For high vacuum SEM the specimen was prepared using two slightly different procedures. After chemical fixation with 2.5% glutaraldehyde in 0.1M phosphate buffer and post-fixation by 1% osmium tetroxide, the specimen was dehydrated by acetone series and dried either by critical point method or by means of t-butylalcohol. For ESEM fresh, unfixed material was used, which was dropped on microscopic copper grids. In FESEM working in cryo-mode the specimen was observed in a frozen state. Ultrathin sections from chemically fixed and Epon embedded specimens were prepared for TEM observation. Distinct parts of sterlet spermatozoa were measured in each microscope and the data obtained was statistically processed. Results confirmed that the classical chemical procedure of specimen preparation for SEM including critical point drying method led to a significant contraction of all measured values, which could deviate up to 30% in comparison with values measured on the fresh chemically untreated specimen in ESEM. Surprisingly sperm dimensions determinated on ultrathin sections by TEM are comparable with values obtained in ESEM or FESEM. Copyright 2010 Elsevier Ltd. All rights reserved.

Surface topography characterization using 3D stereoscopic reconstruction of SEM images

NASA Astrophysics Data System (ADS)

Vedantha Krishna, Amogh; Flys, Olena; Reddy, Vijeth V.; Rosén, B. G.

2018-06-01

A major drawback of the optical microscope is its limitation to resolve finer details. Many microscopes have been developed to overcome the limitations set by the diffraction of visible light. The scanning electron microscope (SEM) is one such alternative: it uses electrons for imaging, which have much smaller wavelength than photons. As a result high magnification with superior image resolution can be achieved. However, SEM generates 2D images which provide limited data for surface measurements and analysis. Often many research areas require the knowledge of 3D structures as they contribute to a comprehensive understanding of microstructure by allowing effective measurements and qualitative visualization of the samples under study. For this reason, stereo photogrammetry technique is employed to convert SEM images into 3D measurable data. This paper aims to utilize a stereoscopic reconstruction technique as a reliable method for characterization of surface topography. Reconstructed results from SEM images are compared with coherence scanning interferometer (CSI) results obtained by measuring a roughness reference standard sample. This paper presents a method to select the most robust/consistent surface texture parameters that are insensitive to the uncertainties involved in the reconstruction technique itself. Results from the two-stereoscopic reconstruction algorithms are also documented in this paper.

Development of 1500mm Wide Wrought Magnesium Alloys by Twin Roll Casting Technique in Turkey

NASA Astrophysics Data System (ADS)

Duygulu, Ozgur; Ucuncuoglu, Selda; Oktay, Gizem; Temur, Deniz Sultan; Yucel, Onuralp; Kaya, Ali Arslan

Magnesium alloy AZ31, AZ61, AZ91, AM50 and AM60 sheets were produced by twin roll casting first time in Turkey. Sheets of 4.5-6.5mm thick and 1500mm width were successfully achieved. Microstructure of the sheet was analyzed by optical microscope, scanning electron microscope (SEM) and transmission electron microscope (TEM). Semi-quantitative analyses were performed by SEM-EDS. In addition, X-ray studies were performed for both characterization and texture purposes. Mechanical properties were investigated by tensile tests and also hardness measurements. Homogenization and annealing heat treatments were performed on the produced sheets.

The Cladophora glomerata Enriched by Biosorption Process in Cr(III) Improves Viability, and Reduces Oxidative Stress and Apoptosis in Equine Metabolic Syndrome Derived Adipose Mesenchymal Stromal Stem Cells (ASCs) and Their Extracellular Vesicles (MV’s)

PubMed Central

Marycz, Krzysztof; Marędziak, Monika; Weiss, Christine

2017-01-01

This study investigated in vitro effects of freshwater alga Cladophora glomerata water extract enriched during a biosorption process in Cr(III) trivalent chromium and chromium picolinate on adipose-derived mesenchymal stromal stem cells (ASCs) and extracellular microvesicles (MVs) in equine metabolic syndrome-affected horses. Chemical characterisation of natural Cladophora glomerata was performed with special emphasis on: vitamin C, vitamin E, total phenols, fatty acids, free and protein-bound amino acids as well as measured Cr in algal biomass. To examine the influence of Cladophora glomerata water extracts, in vitro viability, oxidative stress factor accumulation, apoptosis, inflammatory response, biogenesis of mitochondria, autophagy in ASCs of EMS and secretory activity manifested by MV release were investigated. For this purpose, various methods of molecular biology and microscopic observations (i.e., immunofluorescence staining, SEM, TEM, FIB observations, mRNA and microRNA expression by RT-qPCR) were applied. The extract of Cladophora glomerata enriched with Cr(III) ions reduced apoptosis and inflammation in ASCs of EMS horses through improvement of mitochondrial dynamics, decreasing of PDK4 expression and reduction of endoplastic reticulum stress. Moreover, it was found, that Cladophora glomerata and Cr(III) induce antioxidative protection coming from enhanced SOD activity Therefore, Cladophora glomerata enriched with Cr(III) ions might become an interesting future therapeutic agent in the pharmacological treatment of EMS horses. PMID:29292726

The Cladophora glomerata Enriched by Biosorption Process in Cr(III) Improves Viability, and Reduces Oxidative Stress and Apoptosis in Equine Metabolic Syndrome Derived Adipose Mesenchymal Stromal Stem Cells (ASCs) and Their Extracellular Vesicles (MV's).

PubMed

Marycz, Krzysztof; Michalak, Izabela; Kocherova, Ievgeniia; Marędziak, Monika; Weiss, Christine

2017-12-08

This study investigated in vitro effects of freshwater alga Cladophora glomerata water extract enriched during a biosorption process in Cr(III) trivalent chromium and chromium picolinate on adipose-derived mesenchymal stromal stem cells (ASCs) and extracellular microvesicles (MVs) in equine metabolic syndrome-affected horses. Chemical characterisation of natural Cladophora glomerata was performed with special emphasis on: vitamin C, vitamin E, total phenols, fatty acids, free and protein-bound amino acids as well as measured Cr in algal biomass. To examine the influence of Cladophora glomerata water extracts, in vitro viability, oxidative stress factor accumulation, apoptosis, inflammatory response, biogenesis of mitochondria, autophagy in ASCs of EMS and secretory activity manifested by MV release were investigated. For this purpose, various methods of molecular biology and microscopic observations (i.e., immunofluorescence staining, SEM, TEM, FIB observations, mRNA and microRNA expression by RT-qPCR) were applied. The extract of Cladophora glomerata enriched with Cr(III) ions reduced apoptosis and inflammation in ASCs of EMS horses through improvement of mitochondrial dynamics, decreasing of PDK4 expression and reduction of endoplastic reticulum stress. Moreover, it was found, that Cladophora glomerata and Cr(III) induce antioxidative protection coming from enhanced SOD activity Therefore, Cladophora glomerata enriched with Cr(III) ions might become an interesting future therapeutic agent in the pharmacological treatment of EMS horses.

Estimation of plasma fibrinogen levels based on hemoglobin, base excess and Injury Severity Score upon emergency room admission

PubMed Central

2013-01-01

Introduction Fibrinogen plays a key role in hemostasis and is the first coagulation factor to reach critical levels in massively bleeding trauma patients. Consequently, rapid estimation of plasma fibrinogen (FIB) is essential upon emergency room (ER) admission, but is not part of routine coagulation monitoring in many centers. We investigated the predictive ability of the laboratory parameters hemoglobin (Hb) and base excess (BE) upon admission, as well as the Injury Severity Score (ISS), to estimate FIB in major trauma patients. Methods In this retrospective study, major trauma patients (ISS ≥16) with documented FIB analysis upon ER admission were eligible for inclusion. FIB was correlated with Hb, BE and ISS, alone and in combination, using regression analysis. Results A total of 675 patients were enrolled (median ISS 27). FIB upon admission correlated strongly with Hb, BE and ISS. Multiple regression analysis showed that Hb and BE together predicted FIB (adjusted R2 = 0.46; loge(FIB) = 3.567 + 0.223.Hb - 0.007.Hb2 + 0.044.BE), and predictive strength increased when ISS was included (adjusted R2 = 0.51; loge(FIB) = 4.188 + 0.243.Hb - 0.008.Hb2 + 0.036.BE - 0.031.ISS + 0.0003.ISS2). Of all major trauma patients admitted with Hb <12 g/dL, 74% had low (<200 mg/dL) FIB and 54% had critical (<150 mg/dL) FIB. Of patients admitted with Hb <10 g/dL, 89% had low FIB and 73% had critical FIB. These values increased to 93% and 89%, respectively, among patients with an admission Hb <8 g/dL. Sixty-six percent of patients with only a weakly negative BE (<−2 mmol/L) showed low FIB. Of patients with BE <−6 mmol/L upon admission, 81% had low FIB and 63% had critical FIB. The corresponding values for BE <−10 mmol/L were 89% and 78%, respectively. Conclusions Upon ER admission, FIB of major trauma patients shows strong correlation with rapidly obtainable, routine laboratory parameters such as Hb and BE. These two parameters might provide an insightful and rapid tool to identify major trauma patients at risk of acquired hypofibrinogenemia. Early calculation of ISS could further increase the ability to predict FIB in these patients. We propose that FIB can be estimated during the initial phase of trauma care based on bedside tests. PMID:23849249

Experimental production of indicators for microbial sulfur metabolism in the Chelyabinsk LL5 chondrite: meteorites as standards for biomarker detection on Mars

NASA Astrophysics Data System (ADS)

Tait, A. W.; Wilson, S. A.; Tomkins, A. G.; Gagen, E. J.; Southam, G.

2016-12-01

One hurdle to finding evidence for life beyond Earth is being able to identify its chemical, textural and isotopic fingerprints. This is a challenge in environments that can mask biomarker discovery and/or where geochemical and mineralogical limits are still being established. An ideal solution would be to use standards with known chemical and isotopic compositions to reduce/remove any ambiguity of detection. We propose that chondritic meteorites are ideal standards. Chondrites have narrow ranges in mineralogical, chemical and isotopic compositions, including δ34S values. As such, they could preserve biomarkers of theorized sulfur-based metabolisms on Mars. Here, we demonstrate that bacteria can alter the chemistry of chondrites in a detectable and recognisable manner. We exposed polished fragments of the Chelyabinsk LL5 chondrite to an inoculum of the sulfur/iron oxidising bacterium, Acidithiobacillus ferrooxidans. Cell counts and aqueous sulfate concentrations were recorded over the course of a month. Meteorite samples were taken after one, two and four week exposures for FEG-SEM and FIB-SEM imaging, XRD phase analysis, and stable isotope (δ34S) geochemistry. Our electron microscopy work shows that bacteria and associated extracellular polymeric substances coat grains of troilite (FeS) and FeNi alloys. Decreasing aqueous sulfate concentrations, compared to increasing sulfate in abiotic controls, suggests that A. ferrooxidans may have been assimilating the sulfur released by oxidation of troilite. Also, low abundances of secondary minerals that are capable of recording biological fractionation of stable sulfur and/or iron isotopes were also produced: rozenite, gypsum, goethite, lepidocrocite, and jarosite, and may explain the reduction in soluble sulfur. Our FIB-SEM results show that nutrients (e.g., carbon, sulfur and nitrogen) become concentrated in layers at the surfaces of troilite and FeNi alloys within 1 week of incubation. These nutrient-rich regions are encased and preserved beneath mm-scale efflorescences of Fe-oxyhydroxide minerals, essentially fossilizing them. Meteorites that have landed on the surface of Mars are therefore favourable targets for future sample return missions, because they can record unambiguous evidence of a putative biosphere in multiple ways.

FIBRILLIN4 Is Required for Plastoglobule Development and Stress Resistance in Apple and Arabidopsis1[W][OA

PubMed Central

Singh, Dharmendra K.; Maximova, Siela N.; Jensen, Philip J.; Lehman, Brian L.; Ngugi, Henry K.; McNellis, Timothy W.

2010-01-01

The fibrillins are a large family of chloroplast proteins that have been linked with stress tolerance and disease resistance. FIBRILLIN4 (FIB4) is found associated with the photosystem II light-harvesting complex, thylakoids, and plastoglobules, which are chloroplast compartments rich in lipophilic antioxidants. For this study, FIB4 expression was knocked down in apple (Malus 3 domestica) using RNA interference. Plastoglobule osmiophilicity was decreased in fib4 knockdown (fib4 KD) tree chloroplasts compared with the wild type, while total plastoglobule number was unchanged. Compared with the wild type, net photosynthetic CO2 fixation in fib4 KD trees was decreased at high light intensity but was increased at low light intensity. Furthermore, fib4 KD trees produced more anthocyanins than the wild type when transferred from low to high light intensity, indicating greater sensitivity to high light stress. Relative to the wild type, fib4 KD apples were more sensitive to methyl viologen and had higher superoxide levels during methyl viologen treatment. Arabidopsis (Arabidopsis thaliana) fib4 mutants and fib4 KD apples were more susceptible than their wild-type counterparts to the bacterial pathogens Pseudomonas syringae pathovar tomato and Erwinia amylovora, respectively, and were more sensitive to ozone-induced tissue damage. Following ozone stress, plastoglobule osmiophilicity decreased in wild-type apple and remained low in fib4 KD trees; total plastoglobule number increased in fib4 KD apples but not in the wild type. These results indicate that FIB4 is required for plastoglobule development and resistance to multiple stresses. This study suggests that FIB4 is involved in regulating plastoglobule content and that defective regulation of plastoglobule content leads to broad stress sensitivity and altered photosynthetic activity. PMID:20813909

Monitoring and predicting the fecal indicator bacteria concentrations from agricultural, mixed land use and urban stormwater runoff.

PubMed

Paule-Mercado, M A; Ventura, J S; Memon, S A; Jahng, D; Kang, J-H; Lee, C-H

2016-04-15

While the urban runoff are increasingly being studied as a source of fecal indicator bacteria (FIB), less is known about the occurrence of FIB in watershed with mixed land use and ongoing land use and land cover (LULC) change. In this study, Escherichia coli (EC) and fecal streptococcus (FS) were monitored from 2012 to 2013 in agricultural, mixed and urban LULC and analyzed according to the most probable number (MPN). Pearson correlation was used to determine the relationship between FIB and environmental parameters (physicochemical and hydrometeorological). Multiple linear regressions (MLR) were used to identify the significant parameters that affect the FIB concentrations and to predict the response of FIB in LULC change. Overall, the FIB concentrations were higher in urban LULC (EC=3.33-7.39; FS=3.30-7.36log10MPN/100mL) possibly because of runoff from commercial market and 100% impervious cover (IC). Also, during early-summer season; this reflects a greater persistence and growth rate of FIB in a warmer environment. During intra-event, however, the FIB concentrations varied according to site condition. Anthropogenic activities and IC influenced the correlation between the FIB concentrations and environmental parameters. Stormwater temperature (TEMP), turbidity, and TSS positively correlated with the FIB concentrations (p>0.01), since IC increased, implying an accumulation of bacterial sources in urban activities. TEMP, BOD5, turbidity, TSS, and antecedent dry days (ADD) were the most significant explanatory variables for FIB as determined in MLR, possibly because they promoted the FIB growth and survival. The model confirmed the FIB concentrations: EC (R(2)=0.71-0.85; NSE=0.72-0.86) and FS (R(2)=0.65-0.83; NSE=0.66-0.84) are predicted to increase due to urbanization. Therefore, these findings will help in stormwater monitoring strategies, designing the best management practice for FIB removal and as input data for stormwater models. Copyright © 2016 Elsevier B.V. All rights reserved.

3D-characterization of the veneer-zirconia interface using FIB nano-tomography.

PubMed

Mainjot, Amélie K; Douillard, Thierry; Gremillard, Laurent; Sadoun, Michaël J; Chevalier, Jérôme

2013-02-01

The phenomena occurring during zirconia frameworks veneering process are not yet fully understood. In particular the study of zirconia behavior at the interface with the veneer remains a challenge. However this interface has been reported to act on residual stress in the veneering ceramic, which plays a significant role in clinical failures such as chipping. The objective of this study was thus to investigate the veneer-zirconia interface using a recent 3D-analysis tool and to confront these observations to residual stress measurements in the veneering ceramic. Two cross-sectioned bilayered disc samples (veneer on zirconia), exhibiting different residual stress profiles in the veneering ceramic, were investigated using 2D and 3D imaging (respectively Scanning Electron Microscopy (SEM) and Focused Ion Beam nanotomography (FIB-nt), associated with chemical analysis by Energy Dispersive X-ray Spectroscopy (EDS). The observations did not reveal any structural change in the bulk of zirconia layer of both samples. However the presence of structural alterations and sub-surface microcracks were highlighted in the first micrometer of zirconia surface, exclusively for the sample exhibiting interior tensile stress in the veneering ceramic. No interdiffusion phenomena were observed. FIB nanotomography was proven to be a powerful technique to study the veneer-zirconia interface. The determination of the origin and the nature of zirconia alterations need to be further studied. The results of the present study support the hypothesis that zirconia surface property changes could be involved in the development of tensile stress in the veneering ceramic, increasing the risk of chipping. Copyright © 2012 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Transmission Electron Microscopy of Iron Metal in Almahata Sitta Ureilite

NASA Technical Reports Server (NTRS)

Mikouchi, T.; Yubuta, K.; Sugiyama, K.; Aoyagi, Y.; Yasuhara, A.; Mihira, T.; Zolensky, M. E.; Goodrich, C. A.

2013-01-01

Almahata Sitta (AS) is a polymict breccia mainly composed of variable ureilite lithologies with small amounts of chondritic lithologies [1]. Fe metal is a common accessory phase in ureilites, but our earlier study on Fe metals in one of AS fragments (#44) revealed a unique mineralogy never seen in other ureilites [2,3]. In this abstract we report detailed transmission electron microscopy (TEM) on these metal grains to better understand the thermal history of ureilites. We prepared FIB sections of AS#44 by JEOL JIB-4000 from the PTS that was well characterized by SEM-EBSD in our earlier study [2]. The sections were then observed by STEM (JEOL JEM- 2100F). One of the FIB sections shows a submicron-sized symplectic intergrown texture composed of Fe metal (kamacite), Fe carbide (cohenite), Fe phosphide (schreibersite), and Fe sulfide (troilite). Each phase has an identical SAED pattern in spite of its complex texture, suggesting co-crystallization of all phases. This is probably caused by shock re-melting of pre-existing metal + graphite to form a eutectic-looking texture. The other FIB section is mostly composed of homogeneous Fe metal (93 wt% Fe, 5 wt% Ni, and 2 wt% Si), but BF-STEM images exhibited the presence of elongated lathy grains (approx. 2 microns long) embedded in the interstitial matrix. The SAED patterns from these lath grains could be indexed by alpha-Fe (bcc) while interstitial areas are gamma-Fe (fcc). The elongated alpha-Fe grains show tweed-like structures suggesting martensite transformation. Such a texture can be formed by rapid cooling from high temperature where gamma-Fe was stable. Subsequently alpha-Fe crystallized, but gamma-Fe remained in the interstitial matrix due to quenching from high temperature. This scenario is consistent with very rapid cooling history of ureilites suggested by silicate mineralogy.

Visualizing preparation using asymmetrical choline-like ionic liquids for scanning electron microscope observation of non-conductive biological samples.

PubMed

Abe, Shigeaki; Hyono, Atsushi; Kawai, Koji; Yonezawa, Tetsu

2014-03-01

In this study, we investigated conductivity preparation for scanning electron microscope (SEM) observation that used novel asymmetrical choline-type room temperature ionic liquids (RTIL). By immersion in only an RTIL solution, clear SEM images of several types of biological samples were successfully observed. In addition, we could visualize protozoans using RTILs without any dilution. These results suggested that the asymmetrical choline-type RTILs used in this study are suitable for visualizing of biological samples by SEM. Treatment without the need for dilution can obviate the need for adjusting the RTIL concentration and provide for a rapid and easy conductivity treatment for insulating samples.

SEM analysis of ionizing radiation effects in linear integrated circuits. [Scanning Electron Microscope

NASA Technical Reports Server (NTRS)

Stanley, A. G.; Gauthier, M. K.

1977-01-01

A successful diagnostic technique was developed using a scanning electron microscope (SEM) as a precision tool to determine ionization effects in integrated circuits. Previous SEM methods radiated the entire semiconductor chip or major areas. The large area exposure methods do not reveal the exact components which are sensitive to radiation. To locate these sensitive components a new method was developed, which consisted in successively irradiating selected components on the device chip with equal doses of electrons /10 to the 6th rad (Si)/, while the whole device was subjected to representative bias conditions. A suitable device parameter was measured in situ after each successive irradiation with the beam off.

Evaluation of potential sources and transport mechanisms of fecal indicator bacteria to beach water, Murphy Park Beach, Door County, Wisconsin

USGS Publications Warehouse

Juckem, Paul F.; Corsi, Steven R.; McDermott, Colleen; Kleinheinz, Gregory; Fogarty, Lisa R.; Haack, Sheridan K.; Johnson, Heather E.

2013-01-01

Fecal Indicator Bacteria (FIB) concentrations in beach water have been used for many years as a criterion for closing beaches due to potential health concerns. Yet, current understanding of sources and transport mechanisms that drive FIB occurrence remains insufficient for accurate prediction of closures at many beaches. Murphy Park Beach, a relatively pristine beach on Green Bay in Door County, Wis., was selected for a study to evaluate FIB sources and transport mechanisms. Although the relatively pristine nature of the beach yielded no detection of pathogenic bacterial genes and relatively low FIB concentrations during the study period compared with other Great Lakes Beaches, its selection limited the number of confounding FIB sources and associated transport mechanisms. The primary sources of FIB appear to be internal to the beach rather than external sources such as rivers, storm sewer outfalls, and industrial discharges. Three potential FIB sources were identified: sand, swash-zone groundwater, and Cladophora mats. Modest correlations between FIB concentrations in these potential source reservoirs and FIB concentrations at the beach from the same day illustrate the importance of understanding transport mechanisms between FIB sources and the water column. One likely mechanism for transport and dispersion of FIB from sand and Cladophora sources appears to be agitation of Cladophora mats and erosion of beach sand due to storm activity, as inferred from storm indicators including turbidity, wave height, current speed, wind speed, sky visibility, 24-hour precipitation, and suspended particulate concentration. FIB concentrations in beach water had a statistically significant relation (p-value ‹0.05) with the magnitude of these storm indicators. In addition, transport of FIB in swash-zone groundwater into beach water appears to be driven by groundwater recharge associated with multiday precipitation and corresponding increased swash-zone groundwater discharge at the beach, as indicated by an increase in the specific conductance of beach water. Understanding the dynamics of FIB sources (sand, swash-zone groundwater, and Cladophora) and transport mechanisms (dispersion and erosion from storm energy, and swash-zone groundwater discharge) is important for improving predictions of potential health risks from FIB in beach water.

Conductive resins improve charging and resolution of acquired images in electron microscopic volume imaging

PubMed Central

Nguyen, Huy Bang; Thai, Truc Quynh; Saitoh, Sei; Wu, Bao; Saitoh, Yurika; Shimo, Satoshi; Fujitani, Hiroshi; Otobe, Hirohide; Ohno, Nobuhiko

2016-01-01

Recent advances in serial block-face imaging using scanning electron microscopy (SEM) have enabled the rapid and efficient acquisition of 3-dimensional (3D) ultrastructural information from a large volume of biological specimens including brain tissues. However, volume imaging under SEM is often hampered by sample charging, and typically requires specific sample preparation to reduce charging and increase image contrast. In the present study, we introduced carbon-based conductive resins for 3D analyses of subcellular ultrastructures, using serial block-face SEM (SBF-SEM) to image samples. Conductive resins were produced by adding the carbon black filler, Ketjen black, to resins commonly used for electron microscopic observations of biological specimens. Carbon black mostly localized around tissues and did not penetrate cells, whereas the conductive resins significantly reduced the charging of samples during SBF-SEM imaging. When serial images were acquired, embedding into the conductive resins improved the resolution of images by facilitating the successful cutting of samples in SBF-SEM. These results suggest that improving the conductivities of resins with a carbon black filler is a simple and useful option for reducing charging and enhancing the resolution of images obtained for volume imaging with SEM. PMID:27020327

Discopersicus n. gen., a New Member of the Family Tylenchidae Örley, 1880 with Detailed SEM Study on Two Known Species of the Genus Discotylenchus Siddiqi, 1980 (Nematoda; Tylenchidae) from Iran.

PubMed

Yaghoubi, Ali; Pourjam, Ebrahim; Álvarez-Ortega, Sergio; Liébanas, Gracia; Atighi, Mohammad Reza; Pedram, Majid

2016-09-01

Discopersicus iranicus n. gen., n. comb., previously described from Iran as a new species under the genus Discotylenchus , is illustrated using light microscope and scanning electron microscope (SEM) observations and further studied using molecular characters. SEM studies revealed the newly proposed genus has oblique amphidial apertures on the lateral sides of the lip region. SEM images are also provided for two species of Discotylenchus , namely D. discretus and D. brevicaudatus , as the first SEM study of the genus . These results confirmed longitudinal amphidial aperture type on lateral sides of the lip region in genus Discotylenchus , as noted by Siddiqi while erecting the genus with D. discretus as the type species . Molecular phylogenetic analyses using partial small subunit (SSU) and large subunit (LSU) rDNA sequences revealed the affinity of the genus Discopersicus n. gen. with members of the subfamily Boleodorinae, as supported by morphological characters (mainly, the oblique amphidial opening).

SEM probe of IC radiation sensitivity

NASA Technical Reports Server (NTRS)

Gauthier, M. K.; Stanley, A. G.

1979-01-01

Scanning Electron Microscope (SEM) used to irradiate single integrated circuit (IC) subcomponent to test for radiation sensitivity can localize area of IC less than .03 by .03 mm for determination of exact location of radiation sensitive section.

Correlative SEM SERS for quantitative analysis of dimer nanoparticles.

PubMed

Timmermans, F J; Lenferink, A T M; van Wolferen, H A G M; Otto, C

2016-11-14

A Raman microscope integrated with a scanning electron microscope was used to investigate plasmonic structures by correlative SEM-SERS analysis. The integrated Raman-SEM microscope combines high-resolution electron microscopy information with SERS signal enhancement from selected nanostructures with adsorbed Raman reporter molecules. Correlative analysis is performed for dimers of two gold nanospheres. Dimers were selected on the basis of SEM images from multi aggregate samples. The effect of the orientation of the dimer with respect to the polarization state of the laser light and the effect of the particle gap size on the Raman signal intensity is observed. Additionally, calculations are performed to simulate the electric near field enhancement. These simulations are based on the morphologies observed by electron microscopy. In this way the experiments are compared with the enhancement factor calculated with near field simulations and are subsequently used to quantify the SERS enhancement factor. Large differences between experimentally observed and calculated enhancement factors are regularly detected, a phenomenon caused by nanoscale differences between the real and 'simplified' simulated structures. Quantitative SERS experiments reveal the structure induced enhancement factor, ranging from ∼200 to ∼20 000, averaged over the full nanostructure surface. The results demonstrate correlative Raman-SEM microscopy for the quantitative analysis of plasmonic particles and structures, thus enabling a new analytical method in the field of SERS and plasmonics.

Evaluation of correlation between dissolution rates of loxoprofen tablets and their surface morphology observed by scanning electron microscope and atomic force microscope.

PubMed

Yoshikawa, Shinichi; Murata, Ryo; Shida, Shigenari; Uwai, Koji; Suzuki, Tsuneyoshi; Katsumata, Shunji; Takeshita, Mitsuhiro

2010-01-01

We observed the surface morphological structures of 60 mg tablets of Loxonin, Loxot, and Lobu using scanning electron microscope (SEM) and atomic force microscope (AFM) to evaluate the dissolution rates. We found a significant difference among the initial dissolution rates of the three kinds of loxoprofen sodium tablets. Petal forms of different sizes were commonly observed on the surface of the Loxonin and Loxot tablets in which loxoprofen sodium was confirmed by measuring the energy-dispersible X-ray (EDX) spectrum of NaKalpha using SEM. However, a petal form was not observed on the surface of the Lobu tablet, indicating differences among the drug production processes. Surface area and particle size of the principal ingredient in tablets are important factors for dissolution rate. The mean size of the smallest fine particles constituting each tablet was also determined with AFM. There was a correlation between the initial dissolution rate and the mean size of the smallest particles in each tablet. Visualizing tablet surface morphology using SEM and AFM provides information on the drug production processes and initial dissolution rate, and is associated with the time course of pharmacological activities after tablet administration.

Fundamentals of Focused Ion Beam Nanostructural Processing: Below, At, and Above the Surface

DOE PAGES

MoberlyChan, Warren J.; Adams, David P.; Aziz, Michael J.; ...

2007-05-01

This paper considers the fundamentals of what happens in a solid when it is impacted by a medium-energy gallium ion. The study of the ion/sample interaction at the nanometer scale is applicable to most focused ion beam (FIB)–based work even if the FIB/sample interaction is only a step in the process, for example, micromachining or microelectronics device processing. Whereas the objective in other articles in this issue is to use the FIB tool to characterize a material or to machine a device or transmission electron microscopy sample, the goal of the FIB in this article is to have the FIB/samplemore » interaction itself become the product. To that end, the FIB/sample interaction is considered in three categories according to geometry: below, at, and above the surface. First, the FIB ions can penetrate the top atom layer(s) and interact below the surface. Ion implantation and ion damage on flat surfaces have been comprehensively examined; however, FIB applications require the further investigation of high doses in three-dimensional profiles. Second, the ions can interact at the surface, where a morphological instability can lead to ripples and surface self-organization, which can depend on boundary conditions for site-specific and compound FIB processing. Third, the FIB may interact above the surface (and/or produce secondary particles that interact above the surface). Such ion beam–assisted deposition, FIB–CVD (chemical vapor deposition), offers an elaborate complexity in three dimensions with an FIB using a gas injection system. Finally, at the nanometer scale, these three regimes—below, at, and above the surface—can require an interdependent understanding to be judiciously controlled by the FIB.« less

Transient Elastography is Superior to FIB-4 in Assessing the Risk of Hepatocellular Carcinoma in Patients With Chronic Hepatitis B

PubMed Central

Kim, Seung Up; Kim, Beom Kyung; Park, Jun Yong; Kim, Do Young; Ahn, Sang Hoon; Song, Kijun; Han, Kwang-Hyub

2016-01-01

Abstract Liver stiffness (LS), assessed using transient elastography (TE), and (FIB-4) can both estimate the risk of developing hepatocellular carcinoma (HCC). We compared prognostic performances of LS and FIB-4 to predict HCC development in patients with chronic hepatitis B (CHB). Data from 1308 patients with CHB, who underwent TE, were retrospectively analyzed. FIB-4 was calculated for all patients. The cumulative rate of HCC development was assessed using Kaplan–Meier curves. The predictive performances of LS and FIB-4 were evaluated using time-dependent receiver-operating characteristic (ROC) curves. The mean age (883 men) was 50 years. During follow-up (median 6.1 years), 119 patients developed HCC. The areas under the ROC curves (AUROCs) predicting HCC risk at 3, 5, and 7 years were consistently greater for LS than for FIB-4 (0.791–0.807 vs 0.691–0.725; all P < 0.05). Similarly, when the respective AUROCs for LS and FIB-4 at every time point during the 7-year follow-up were plotted, LS also showed consistently better performance than FIB-4 after 1 year of enrollment. The combined use of LS and FIB-4 significantly enhanced the prognostic performance compared with the use of FIB-4 alone (P < 0.05), but the performance of the combined scores was statistically similar to that of LS alone (P > 0.05). LS showed significantly better performance than FIB-4 in assessing the risk of HCC development, and the combined use of LS and FIB-4 did not provide additional benefit compared with the use of LS alone. Hence, LS assessed using TE might be helpful for optimizing HCC surveillance strategies. PMID:27196449

Transient Elastography is Superior to FIB-4 in Assessing the Risk of Hepatocellular Carcinoma in Patients With Chronic Hepatitis B.

PubMed

Kim, Seung Up; Kim, Beom Kyung; Park, Jun Yong; Kim, Do Young; Ahn, Sang Hoon; Song, Kijun; Han, Kwang-Hyub

2016-05-01

Liver stiffness (LS), assessed using transient elastography (TE), and (FIB-4) can both estimate the risk of developing hepatocellular carcinoma (HCC). We compared prognostic performances of LS and FIB-4 to predict HCC development in patients with chronic hepatitis B (CHB).Data from 1308 patients with CHB, who underwent TE, were retrospectively analyzed. FIB-4 was calculated for all patients. The cumulative rate of HCC development was assessed using Kaplan-Meier curves. The predictive performances of LS and FIB-4 were evaluated using time-dependent receiver-operating characteristic (ROC) curves.The mean age (883 men) was 50 years. During follow-up (median 6.1 years), 119 patients developed HCC. The areas under the ROC curves (AUROCs) predicting HCC risk at 3, 5, and 7 years were consistently greater for LS than for FIB-4 (0.791-0.807 vs 0.691-0.725; all P < 0.05). Similarly, when the respective AUROCs for LS and FIB-4 at every time point during the 7-year follow-up were plotted, LS also showed consistently better performance than FIB-4 after 1 year of enrollment. The combined use of LS and FIB-4 significantly enhanced the prognostic performance compared with the use of FIB-4 alone (P < 0.05), but the performance of the combined scores was statistically similar to that of LS alone (P > 0.05).LS showed significantly better performance than FIB-4 in assessing the risk of HCC development, and the combined use of LS and FIB-4 did not provide additional benefit compared with the use of LS alone. Hence, LS assessed using TE might be helpful for optimizing HCC surveillance strategies.

Reduction of fecal indicator bacteria (FIB) in the Ballona Wetlands saltwater marsh (Los Angeles County, California, USA) with implications for restoration actions.

PubMed

Dorsey, John H; Carter, Patrick M; Bergquist, Sean; Sagarin, Rafe

2010-08-01

A benefit of wetland preservation and restoration is the ecosystem service of improving water quality, typically assessed based on bacterial loading. The Ballona Wetlands, a degraded salt marsh of approximately 100 ac located on the southern border of Marina Del Rey (Los Angeles County, California, USA) are currently the focus of publicly funded restoration planning. The wetlands receive tidal water, usually contaminated with fecal indicator bacteria (FIB: total and fecal coliforms, Escherichia coli, enterococci) from the adjacent Ballona Creek and Estuary. During the summer of 2007, two 24-h studies were conducted to determine FIB tidal dynamics within the wetland. Measurements of water flow and mean FIB concentrations (n = 3) were measured every 1.5 h to determine total FIB load estimates. FIB loading rates (MPN/s) were greatest during flood tides as water entered the wetlands, and then again during spring tide conditions when sediments were resuspended during swifter spring ebb flows. During daylight hours, the wetland acted as a sink for these bacteria as loads diminished, presumably by sunlight and other processes. Conversely, during late afternoon and night, the wetlands shifted to being a source as excess FIB departed on ebb flows. Therefore, the wetlands act as both a source and sink for FIB depending on tidal conditions and exposure to sunlight. Future restoration actions would result in a tradeoff - increased tidal channels offer a greater surface area for FIB inactivation, but also would result in a greater volume of FIB-contaminated resuspended sediments carried out of the wetlands on stronger ebb flows. As levels of FIB in Ballona Creek and Estuary diminish through recently established regulatory actions, the wetlands could shift into a greater sink for FIB. (c) 2010 Elsevier Ltd. All rights reserved.

Understanding fluid transport through the multiscale pore network of a natural shale

NASA Astrophysics Data System (ADS)

Davy, Catherine; Adler, Pierre; Song, Yang; Nguyen, Thang Kim; Troadec, David; Dhénin, Jean-Francois

2017-04-01

Natural shales have a complex pore structure, which is only partly understood today. In the present contribution, a combination of different techniques is used to get information on three different scales. On each scale, the relevant flow equation is solved and provides input for the flow equation of the next higher scale. More precisely, micro-CT, FIB/SEM (Focused Ion Beam/Scanning Electron Microscopy) and TEM (Transmission Electron Microscopy) provide a full representative 3D pore space on the macroscopic scale, the mesoscale and the nanoscale. The corresponding typical voxel sizes are 0.7 μm, 10 nm and 1 nm, respectively. The porosity on the micro-CT images is 0.5 %, and it is not connected. One can distinguish between the pores, the porous clay matrix and non porous minerals; the volume percentages of these last two phases are 0.6 and 0.395, respectively. Samples of the porous clay matrix were analyzed by FIB/SEM which yields 3D information. They have a porosity ranging from 2 to 6 %. In some of them, the pore space is connected. Finally, TEM provides 2D images with a porosity of about 10 to 25 %. These information were used in the following way to estimate the macroscopic permeability which has been measured independently and found equal to 6 x10-20 m2. At the nanoscopic scale analyzed by 2D TEM, in the absence of 3D images, the pore structure is reconstructed by using a technique based on truncated Gaussian fields. Then, the Stokes equations are solved by using a 3D Lattice Boltzmann method. The resulting velocity field is averaged and this provides the permeability K_n. The permeability of the nanoscale structure varies between 0.7x 10-20 and 1.8x10-19 m2. As expected, the material is anisotropic. At the mesoscale, percolation of the FIB/SEM pore volume occurs only along a single direction. The Stokes equations are again solved by the same method and the mesoscopic permeability Km varies between 3.3 10-20 and 1.20 10-18 m2, depending on the nature of the percolating volume. The influence of the nanoscale porosity on the mesoscopic permeability is also studied. Two examples show that despite the scale ratio between the mesoscopic and nanoscopic pores, the nanoscopic pore structure cannot be neglected to estimate the permeability of the pore clay matrix. Finally, the sample provided by micro-CT is considered as a porous medium composed of three phases with permeabilities 0 (for the non porous minerals), 1 (for the porous clay matrix) and infinity (for the macroscopic pores). The overall permeability Kmacro is obtained by solving the Darcy's equation with a variable local permeability with spatially periodic boundary conditions. Kmacro is found of the order of 0.4 and the medium is relatively isotropic on this scale. This estimation of Kmacro is in agreement with the measured value.

Acquisition of a High Resolution Field Emission Scanning Electron Microscope for the Analysis of Returned Samples

NASA Technical Reports Server (NTRS)

Nittler, Larry R.

2003-01-01

This grant furnished funds to purchase a state-of-the-art scanning electron microscope (SEM) to support our analytical facilities for extraterrestrial samples. After evaluating several instruments, we purchased a JEOL 6500F thermal field emission SEM with the following analytical accessories: EDAX energy-dispersive x-ray analysis system with fully automated control of instrument and sample stage; EDAX LEXS wavelength-dispersive x-ray spectrometer for high sensitivity light-element analysis; EDAX/TSL electron backscatter diffraction (EBSD) system with software for phase identification and crystal orientation mapping; Robinson backscatter electron detector; and an in situ micro-manipulator (Kleindiek). The total price was $550,000 (with $150,000 of the purchase supported by Carnegie institution matching funds). The microscope was delivered in October 2002, and most of the analytical accessories were installed by January 2003. With the exception of the wavelength spectrometer (which has been undergoing design changes) everything is working well and the SEM is in routine use in our laboratory.

SOFC Microstructures (PFIB-SEM and synthetic) from JPS 2018

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hsu, Tim; Epting, William K; Mahbub, Rubayyat

This is the microstructural data used in the publication "Mesoscale characterization of local property distributions in hetergeneous electrodes" by Tim Hsu, William K. Epting, Rubayyat Mahbub, et al., published in the Journal of Power Sources in 2018 (DOI 10.1016/j.jpowsour.2018.03.025). Included are a commercial cathode and anode active layer (Materials and Systems Research, Inc., Salt Lake City, UT) imaged by Xe plasma FIB-SEM (FEI, Hillsboro, OR), and four synthetic microstructures of varying particle size distribution widths generated by DREAM3D (BlueQuartz Software, Springboro, OH). For the MSRI electrodes, both the original greyscale and the segmented versions are provided. Each .zip file containsmore » a "stack" of .tif image files in the Z dimension, and an .info ascii text file containing useful information like voxel sizes and phase IDs. More details can be found in the pertinent publication at http://dx.doi.org/10.1016/j.jpowsour.2018.03.025.« less

Enhanced EDX images by fusion of multimodal SEM images using pansharpening techniques.

PubMed

Franchi, G; Angulo, J; Moreaud, M; Sorbier, L

2018-01-01

The goal of this paper is to explore the potential interest of image fusion in the context of multimodal scanning electron microscope (SEM) imaging. In particular, we aim at merging the backscattered electron images that usually have a high spatial resolution but do not provide enough discriminative information to physically classify the nature of the sample, with energy-dispersive X-ray spectroscopy (EDX) images that have discriminative information but a lower spatial resolution. The produced images are named enhanced EDX. To achieve this goal, we have compared the results obtained with classical pansharpening techniques for image fusion with an original approach tailored for multimodal SEM fusion of information. Quantitative assessment is obtained by means of two SEM images and a simulated dataset produced by a software based on PENELOPE. © 2017 The Authors Journal of Microscopy © 2017 Royal Microscopical Society.

Metavir and FIB-4 scores are associated with patient prognosis after curative hepatectomy in hepatitis B virus-related hepatocellular carcinoma: a retrospective cohort study at two centers in China.

PubMed

Liao, Rui; Fu, Yi-Peng; Wang, Ting; Deng, Zhi-Gang; Li, De-Wei; Fan, Jia; Zhou, Jian; Feng, Gen-Sheng; Qiu, Shuang-Jian; Du, Cheng-You

2017-01-03

Although Metavir and Fibrosis-4 (FIB-4) scores are typically used to assess the severity of liver fibrosis, the relationship between these scores and patient outcome in hepatocellular carcinoma (HCC) is unclear. The aim of this study was to evaluate the prognostic value of the severity of hepatic fibrosis in HBV-related HCC patients after curative resection. We examined the prognostic roles of the Metavir and preoperative FIB-4 scores in 432 HBV-HCC patients who underwent curative resection at two different medical centers located in western (Chongqing) and eastern (Shanghai) China. In the testing set (n = 108), the Metavir, FIB-4, and combined Metavir/FIB-4 scores were predictive of overall survival (OS) and recurrence-free survival (RFS). Additionally, they were associated with several clinicopathologic variables. In the validation set (n = 324), the Metavir, FIB-4, and combined Metavir/FIB-4 scores were associated with poor prognosis in HCC patients after curative resection. Importantly, in the negative alpha-fetoprotein subgroup (≤ 20 ng/mL), the FIB-4 index (I vs. II) could discriminate between patient outcomes (high or low OS and RFS). Thus Metavir, preoperative FIB-4, and combined Metavir/FIB-4 scores are prognostic markers in HBV-HCC patients after curative hepatectomy.

Metavir and FIB-4 scores are associated with patient prognosis after curative hepatectomy in hepatitis B virus-related hepatocellular carcinoma: a retrospective cohort study at two centers in China

PubMed Central

Li, De-Wei; Fan, Jia; Zhou, Jian; Feng, Gen-Sheng; Qiu, Shuang-Jian; Du, Cheng-You

2017-01-01

Although Metavir and Fibrosis-4 (FIB-4) scores are typically used to assess the severity of liver fibrosis, the relationship between these scores and patient outcome in hepatocellular carcinoma (HCC) is unclear. The aim of this study was to evaluate the prognostic value of the severity of hepatic fibrosis in HBV-related HCC patients after curative resection. We examined the prognostic roles of the Metavir and preoperative FIB-4 scores in 432 HBV-HCC patients who underwent curative resection at two different medical centers located in western (Chongqing) and eastern (Shanghai) China. In the testing set (n = 108), the Metavir, FIB-4, and combined Metavir/FIB-4 scores were predictive of overall survival (OS) and recurrence-free survival (RFS). Additionally, they were associated with several clinicopathologic variables. In the validation set (n = 324), the Metavir, FIB-4, and combined Metavir/FIB-4 scores were associated with poor prognosis in HCC patients after curative resection. Importantly, in the negative alpha-fetoprotein subgroup (≤ 20 ng/mL), the FIB-4 index (I vs. II) could discriminate between patient outcomes (high or low OS and RFS). Thus Metavir, preoperative FIB-4, and combined Metavir/FIB-4 scores are prognostic markers in HBV-HCC patients after curative hepatectomy. PMID:27662665

Electron-beam-induced potentials in semiconductors: calculation and measurement with an SEM/SPM hybrid system

NASA Astrophysics Data System (ADS)

Thomas, Ch; Joachimsthaler, I.; Heiderhoff, R.; Balk, L. J.

2004-10-01

In this work electron-beam-induced potentials are analysed theoretically and experimentally for semiconductors. A theoretical model is developed to describe the surface potential distribution produced by an electron beam. The distribution of generated carriers is calculated using semiconductor equations. This distribution causes a local change in surface potential, which is derived with the help of quasi-Fermi energies. The potential distribution is simulated using the model developed and measured with a scanning probe microscope (SPM) built inside a scanning electron microscope (SEM), for different samples, for different beam excitations and for different cantilever voltages of SPM. In the end, some fields of application are shown where material properties can be determined using an SEM/SPM hybrid system.

KLASS: Kennedy Launch Academy Simulation System

NASA Technical Reports Server (NTRS)

Garner, Lesley C.

2007-01-01

Software provides access to many sophisticated scientific instrumentation (Scanning Electron Microscope (SEM), a Light Microscope, a Scanning Probe Microscope (covering Scanning Tunneling, Atomic Force, and Magnetic Force microscopy), and an Energy Dispersive Spectrometer for the SEM). Flash animation videos explain how each of the instruments work. Videos on how they are used at NASA and the sample preparation. Measuring and labeling tools provided with each instrument. Hands on experience of controlling the virtual instrument to conduct investigations, much like the real scientists at NASA do. Very open architecture. Open source on SourceForge. Extensive use of XML Target audience is high school and entry-level college students. "Many beginning students never get closer to an electron microscope than the photos in their textbooks. But anyone can get a sense of what the instrument can do by downloading this simulator from NASA's Kennedy Space Center." Science Magazine, April 8th, 2005

Morphology-controllable of Sn doped ZnO nanorods prepared by spray pyrolysis for transparent electrode application

NASA Astrophysics Data System (ADS)

Hameed, M. Shahul; Princice, J. Joseph; Babu, N. Ramesh; Zahirullah, S. Syed; Deshmukh, Sampat G.; Arunachalam, A.

2018-05-01

Transparent conductive Sn doped ZnO nanorods have been deposited at various doping level by spray pyrolysis technique on glass substrate. The structural, surface morphological and optical properties of these films have been investigated with the help of X-ray diffraction (XRD), scanning electron microscope (SEM), atomic force microscope (AFM) and UV-Vis spectrophotometer respectively. XRD patterns revealed a successful high quality growth of single crystal ZnO nanorods with hexagonal wurtzite structure having (002) preferred orientation. The scanning electron microscope (SEM) image of the prepared films exposed the uniform distribution of Sn doped ZnO nanorod shaped grains. All these films were highly transparent in the visible region with average transmittance of 90%.

A Miniaturized Variable Pressure Scanning Electron Microscope (MVP-SEM) for In-Situ Mars Surface Sample Analysis

NASA Technical Reports Server (NTRS)

Edmunson, J.; Gaskin, J. A.; Jerman, G. A.; Harvey, R. P.; Doloboff, I. J.; Neidholdt, E. L.

2016-01-01

The Miniaturized Variable Pressure Scanning Electron Microscope (MVP-SEM) project, funded by the NASA Planetary Instrument Concepts for the Advancement of Solar System Observations (PICASSO) Research Opportunities in Space and Earth Sciences (ROSES), will build upon previous miniaturized SEM designs and recent advancements in variable pressure SEM's to design and build a SEM to complete analyses of samples on the surface of Mars using the atmosphere as an imaging medium. This project is a collaboration between NASA Marshall Space Flight Center (MSFC), the Jet Propulsion Laboratory (JPL), electron gun and optics manufacturer Applied Physics Technologies, and small vacuum system manufacturer Creare. Dr. Ralph Harvery and environmental SEM (ESEM) inventor Dr. Gerry Danilatos serve as advisors to the team. Variable pressure SEMs allow for fine (nm-scale) resolution imaging and micron-scale chemical study of materials without sample preparation (e.g., carbon or gold coating). Charging of a sample is reduced or eliminated by the gas surrounding the sample. It is this property of ESEMs that make them ideal for locations where sample preparation is not yet feasible, such as the surface of Mars. In addition, the lack of sample preparation needed here will simplify the sample acquisition process and allow caching of the samples for future complementary payload use.

On the Progress of Scanning Transmission Electron Microscopy (STEM) Imaging in a Scanning Electron Microscope.

PubMed

Sun, Cheng; Müller, Erich; Meffert, Matthias; Gerthsen, Dagmar

2018-04-01

Transmission electron microscopy (TEM) with low-energy electrons has been recognized as an important addition to the family of electron microscopies as it may avoid knock-on damage and increase the contrast of weakly scattering objects. Scanning electron microscopes (SEMs) are well suited for low-energy electron microscopy with maximum electron energies of 30 keV, but they are mainly used for topography imaging of bulk samples. Implementation of a scanning transmission electron microscopy (STEM) detector and a charge-coupled-device camera for the acquisition of on-axis transmission electron diffraction (TED) patterns, in combination with recent resolution improvements, make SEMs highly interesting for structure analysis of some electron-transparent specimens which are traditionally investigated by TEM. A new aspect is correlative SEM, STEM, and TED imaging from the same specimen region in a SEM which leads to a wealth of information. Simultaneous image acquisition gives information on surface topography, inner structure including crystal defects and qualitative material contrast. Lattice-fringe resolution is obtained in bright-field STEM imaging. The benefits of correlative SEM/STEM/TED imaging in a SEM are exemplified by structure analyses from representative sample classes such as nanoparticulates and bulk materials.

A laboratory marker, FIB-4 index, as a predictor for long-term outcomes of hepatocellular carcinoma patients after curative hepatic resection.

PubMed

Toyoda, Hidenori; Kumada, Takashi; Tada, Toshifumi; Kaneoka, Yuji; Maeda, Atsuyuki

2015-04-01

Liver fibrosis is associated with the prognosis of patients with hepatocellular carcinoma (HCC) after treatment. The laboratory marker for liver fibrosis, the FIB-4 index, is reportedly correlated with the degree of liver fibrosis. We evaluated the predictive value of FIB-4 index on the recurrence and survival of HCC patients who underwent curative hepatectomy. A total of 431 consecutive patients who underwent hepatectomy for primary, nonrecurrent HCC were analyzed. The FIB-4 index was calculated from the patient's age, serum alanine aminotransferase and aspartate aminotransferase levels, and platelet count at the time of HCC diagnosis. Postoperative recurrence and survival rates were compared according to tumor characteristics, tumor markers, Child-Pugh class, and the FIB-4 index. The pretreatment FIB-4 index was associated with recurrence and survival rates, independent of HCC progression or tumor marker levels in a multivariate analysis. Recurrence rates after hepatectomy were higher in patients with a FIB-4 index >3.25 versus ≤3.25 (5-year recurrence rates 69.6% vs 54.8%; P = .0049). Survival was also worse in patients with a FIB-4 index >3.25 than those with a FIB-4 index ≤3.25 (5-year survival rates 67.1% vs 72.2%; P = .0030). The FIB-4 index is a predictive marker for long-term outcomes in patients with HCC treated with curative hepatic resection. Copyright © 2015 Elsevier Inc. All rights reserved.

Disruption of adherens junction and alterations in YAP-related proliferation behavior as part of the underlying cell transformation process of alcohol-induced oral carcinogenesis.

PubMed

Husari, Ayman; Hülter-Hassler, Diana; Steinberg, Thorsten; Schulz, Simon Daniel; Tomakidi, Pascal

2018-01-01

Accumulating evidences indicate that alcohol might play a causative in oral cancer. Unfortunately, in vitro cell systems, uncovering the molecular background of the underlying cell transformation process, are rare. Therefore, this study was conducted, to identify molecular changes and characterize their putative cell behavioral consequences in epitheloid (EPI) and fibroblastoid (FIB) oral keratinocyte phenotypes, arising from chronical alcohol treatment. Concerning adherens junctions (AJs), both EPI and FIB showed membrane-bound β-catenin, but exhibited differences for E-cadherin and zyxin. While EPI revealed E-cadherin/β-catenin membrane co-localization, which in parts also applied for zyxin, FIB membranes were devoid of E-cadherin and exhibited marginal zyxin expression. Fetal calf serum (FCS) administration in starved cells promoted proliferation in both keratinocyte phenotypes, whereat EPI and FIB yielded a strikingly modified FCS sensitivity on the temporal scale. Impedance measurement-based cell index detection yielded proliferation stimulation occurring much earlier in FIB (<20h) compared to EPI (>45h). Nuclear preference of the proliferation-associated YAP co-transcription factor in FIB was FCS independent, while it required FCS in EPI. Taken together, the lack of membrane-inherent E-cadherin/β-catenin co-localization together with low zyxin - reveals perturbation of AJ integrity in FIB. Regarding cell behavior, perturbed AJs in FIB correlate with temporal proliferation sensitivity towards FCS. CYF of 5.6 strongly suggests involvement of chromatin-bound YAP in FIB's proliferation temperosensitivity. These molecular differences detected for EPI and FIB are part of the underlying cell transformation process of alcohol-induced oral carcinogenesis, and indicate FIB being in a more advanced transformation stage. Copyright © 2017 Elsevier B.V. All rights reserved.

Improving yield and reliability of FIB modifications using electrical testing

NASA Astrophysics Data System (ADS)

Desplats, Romain; Benbrik, Jamel; Benteo, Bruno; Perdu, Philippe

1998-08-01

Focused Ion Beam technology has two main areas of application for ICs: modification and preparation for technological analysis. The most solicited area is modification. This involves physically modifying a circuit by cutting lines and creating new ones in order to change the electrical function of the circuit. IC planar technologies have an increasing number of metal interconnections making FIB modifications more complex and decreasing their changes of success. The yield of FIB operations on ICs reflects a downward trend that imposes a greater number of circuits to be modified in order to successfully correct a small number of them. This requires extended duration, which is not compatible with production line turn around times. To respond to this problem, two solutions can be defined: either, reducing the duration of each FIB operation or increasing the success rate of FIB modifications. Since reducing the time depends mainly on FIB operator experience, insuring a higher success rate represents a more crucial aspect as both experienced and novice operators could benefit from this improvement. In order to insure successful modifications, it is necessary to control each step of a FIB operation. To do this, we have developed a new method using in situ electrical testing which has a direct impact on the yield of FIB modifications. We will present this innovative development through a real case study of a CMOS ASIC for high-speed communications. Monitoring the electrical behavior at each step in a FIB operation makes it possible to reduce the number of circuits to be modified and consequently reduces system costs thanks to better yield control. Knowing the internal electrical behavior also gives us indications about the impact on reliability of FIB modified circuits. Finally, this approach can be applied to failure analysis and FIB operations on flip chip circuits.

HIV mono-infection is associated with FIB-4 - A noninvasive index of liver fibrosis - in women.

PubMed

Blackard, Jason T; Welge, Jeffrey A; Taylor, Lynn E; Mayer, Kenneth H; Klein, Robert S; Celentano, David D; Jamieson, Denise J; Gardner, Lytt; Sherman, Kenneth E

2011-03-01

FIB-4 represents a noninvasive, composite index that is a validated measure of hepatic fibrosis, which is an important indicator of liver disease. To date, there are limited data regarding hepatic fibrosis in women. FIB-4 was evaluated in a cohort of 1227 women, and associations were evaluated in univariate and multivariate regression models among 4 groups of subjects classified by their human immunodeficiency virus (HIV) and hepatitis C virus (HCV) infection status. The median FIB-4 scores were 0.60 in HIV-/HCV- women, 0.83 in HIV-/HCV+ women, 0.86 in HIV+/HCV- women, and 1.30 in HIV+/HCV+ women. In the HIV/HCV co-infected group, multivariate analysis showed that CD4(+) cell count and albumin level were negatively associated with FIB-4 (P <.0001), whereas antiretroviral therapy (ART) was positively associated with FIB-4 score (P =.0008). For the HIV mono-infected group, multivariate analysis showed that CD4(+) cell count (P <.0001) and albumin level (P =.0019) were negatively correlated with FIB-4 score, ART was positively associated with FIB-4 score (P =.0008), and plasma HIV RNA level was marginally associated with FIB-4 score (P =.080). In 72 HIV mono-infected women who were also hepatitis B surface antigen negative, ART naive, and reported no recent alcohol intake, plasma HIV RNA level was associated with increased FIB-4 score (P =.030). HIV RNA level was associated with increased FIB-4 score in the absence of hepatitis B, hepatitis C, ART, or alcohol use, suggesting a potential relationship between HIV infection and hepatic fibrosis in vivo. A better understanding of the various demographic and virologic variables that contribute to hepatic fibrosis may lead to more effective treatment of HIV infection and its co-morbid conditions.

FIB-4 index is associated with hepatocellular carcinoma risk in HIV-infected patients.

PubMed

Park, Lesley S; Tate, Janet P; Justice, Amy C; Lo Re, Vincent; Lim, Joseph K; Bräu, Norbert; Brown, Sheldon T; Butt, Adeel A; Gibert, Cynthia; Goetz, Matthew Bidwell; Rimland, David; Rodriguez-Barradas, Maria C; Dubrow, Robert

2011-12-01

Chronic inflammation caused by hepatitis B virus infection, hepatitis C virus infection, and/or heavy alcohol use can lead to fibrosis, cirrhosis, and eventually hepatocellular carcinoma (HCC). FIB-4 is an index score calculated from platelet count, alanine transaminase, aspartate transaminase, and age that predicts fibrosis and cirrhosis. We hypothesized that high FIB-4 would be associated with development of HCC in HIV-infected persons, who are at high risk due to high prevalence of viral hepatitis and alcohol consumption, and possibly due to HIV infection itself. Using proportional hazards models, we tested this hypothesis among 22,980 HIV-infected men from the Veterans Aging Cohort Study. We identified incident HCC cases from the Veterans Affairs Central Cancer Registry. During follow-up, there were 112 incident HCC diagnoses. The age- and race/ethnic group-adjusted HR was 4.2 [95% confidence interval (CI), 2.4-7.4] for intermediate FIB-4 and 13.0 (95% CI, 7.2-23.4) for high FIB-4, compared with low FIB-4. After further adjustment for enrollment year, CD4 count, HIV-1 RNA level, antiretroviral therapy use, hepatitis B and C virus infection, alcohol abuse/dependency, and diabetes, FIB-4 remained a strong, significant, independent risk factor for HCC. The multivariate-adjusted HR was 3.6 (95% CI, 2.1-6.4) for intermediate FIB-4 and 9.6 (95% CI, 5.2-17.4) for high FIB-4. Calculated from routine, noninvasive laboratory tests, FIB-4 is a strong, independent HCC risk factor in HIV-infected patients. FIB-4 might prove valuable as an easily measured index to identify those at highest risk for HCC, even prior to development of clinical cirrhosis.

FIB-4 Index is a Predictor of Background Liver Fibrosis and Long-Term Outcomes After Curative Resection of Hepatocellular Carcinoma.

PubMed

Okamura, Yukiyasu; Ashida, Ryo; Yamamoto, Yusuke; Ito, Takaaki; Sugiura, Teiichi; Uesaka, Katsuhiko

2016-08-01

The FIB-4 index is a simple formula for predicting the degree of liver fibrosis. This study aimed to examine the relationship between the preoperative FIB-4 index and liver fibrosis in non-tumor regions of surgical specimens and to investigate whether the FIB-4 index is a useful predictor for long-term outcomes experienced by hepatocellular carcinoma (HCC) patients after curative resection. This study retrospectively analyzed 493 HCC patients treated with curative resection. The utility of the FIB-4 index as a predictor of advanced liver fibrosis (F3 or F4) was assessed. The cutoff value for the FIB-4 index was determined using a receiver operating characteristic curve analysis, and the impact of the FIB-4 index on overall and recurrence-free survival after surgery was evaluated. Advanced liver fibrosis was found in 236 patients (47.9 %). The FIB-4 index was significantly higher for the patients with advanced liver fibrosis than for those without this condition (P < 0.001). An FIB-4 index of 2.87 was the optimal cutoff point for predicting advanced liver fibrosis. The multivariate analysis showed the FIB-4 index to be an independent prognostic factor for recurrence-free and overall survival after curative resection only for patients who underwent hepatectomy as initial treatment (hazard ratio, 1.47 and 1.59; 95 % confidence interval, 1.12-1.93 and 1.09-2.32; P = 0.006 and 0.016, respectively). The study showed the FIB4-index to be a predictor of background liver fibrosis and long-term outcomes for HCC patients who underwent hepatectomy as their initial treatment.

Sample Preparation Techniques for Grain Boundary Characterization of Annealed TRISO-Coated Particles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dunzik-Gougar, M. L.; van Rooyen, I. J.; Hill, C. M.

Crystallographic information about chemical vapor deposition layers of silicon carbide (SiC) is essential to understanding layer performance, especially when the layers are in non planar geometries, such as spherical. We performed electron Back Scatter Diffraction (EBSD) analysis of spherical SiC layers using a different approach to sample focus ion beam milling technique to avoid the negative impacts of traditional sample polishing and to address the need of very small samples of irradiated materials for analysis. Mechanical and chemical grinding and polishing of sample surfaces can introduce lattice strains and result in unequal removal of SiC and surrounding layers of differentmore » material due to the hardness differences of these materials. The nature of layer interfaces is thought to play a key role in performance of the SiC; therefore, analysis of representative samples at these interfacial areas is crucial. In work reported here, a focused ion beam (FIB) was employed in a novel manner to prepare a more representative sample for EBSD analysis from TRISO layers free of effects introduced by mechanical and chemical preparation methods. In addition, the difficulty of handling neutron irradiated microscopic samples such as those analyzed in this work has been simplified with pre tilted mounting stages. Our study showed that although the average grain size of samples may be similar, the grain boundary characteristics may differ significantly. It was also found that low angle grain boundaries, comprises 25% in the FIB-prepared sample vs only 1-2% in the polished sample measured in the same particle. From this study it was determined that results of FIB prepared sample will provide more repeatable results, as the role of sample preparation is eliminated.« less

Sample Preparation Techniques for Grain Boundary Characterization of Annealed TRISO-Coated Particles

DOE PAGES

Dunzik-Gougar, M. L.; van Rooyen, I. J.; Hill, C. M.; ...

2016-08-25

Crystallographic information about chemical vapor deposition layers of silicon carbide (SiC) is essential to understanding layer performance, especially when the layers are in non planar geometries, such as spherical. We performed electron Back Scatter Diffraction (EBSD) analysis of spherical SiC layers using a different approach to sample focus ion beam milling technique to avoid the negative impacts of traditional sample polishing and to address the need of very small samples of irradiated materials for analysis. Mechanical and chemical grinding and polishing of sample surfaces can introduce lattice strains and result in unequal removal of SiC and surrounding layers of differentmore » material due to the hardness differences of these materials. The nature of layer interfaces is thought to play a key role in performance of the SiC; therefore, analysis of representative samples at these interfacial areas is crucial. In work reported here, a focused ion beam (FIB) was employed in a novel manner to prepare a more representative sample for EBSD analysis from TRISO layers free of effects introduced by mechanical and chemical preparation methods. In addition, the difficulty of handling neutron irradiated microscopic samples such as those analyzed in this work has been simplified with pre tilted mounting stages. Our study showed that although the average grain size of samples may be similar, the grain boundary characteristics may differ significantly. It was also found that low angle grain boundaries, comprises 25% in the FIB-prepared sample vs only 1-2% in the polished sample measured in the same particle. From this study it was determined that results of FIB prepared sample will provide more repeatable results, as the role of sample preparation is eliminated.« less

Observation of three-dimensional elemental distributions of a Si device using a 360 degrees -tilt FIB and the cold field-emission STEM system.

PubMed

Yaguchi, Toshie; Konno, Mitsuru; Kamino, Takeo; Watanabe, Masashi

2008-11-01

A technique for preparation of a pillar-shaped specimen and its multidirectional observation using a combination of a scanning transmission electron microscope (STEM) and a focused ion beam (FIB) instrument has been developed. The system employs an FIB/STEM compatible holder with a specially designed tilt mechanism, which allows the specimen to be tilted through 360 degrees [T. Yaguchi, M. Konno, T. Kamino, T. Hashimoto, T. Ohnishi, K. Umemura, K. Asayama, Microsc. Microanal. 9 (Suppl. 2) (2003) 118; T. Yaguchi, M. Konno, T. Kamino, T. Hashimoto, T. Ohnishi, M. Watanabe, Microsc. Microanal. 10 (Suppl. 2) (2004) 1030]. This technique was applied to obtain the three-dimensional (3D) elemental distributions around a contact plug of a Si device used in a 90-nm technology. A specimen containing only one contact plug was prepared in the shape of a pillar with a diameter of 200nm and a length of 5mum. Elemental maps were obtained from the pillar specimen using a 200-kV cold-field emission gun (FEG) STEM model HD-2300C equipped with the EDAX genesis X-ray energy-dispersive spectrometry (XEDS) system through a spectrum imaging technique. In this study, elemental distributions of minor elements with weak signals were enhanced by applying principal component analysis (PCA), which is a superior technique to extract weak signals from a large dataset. The distributions of elements, especially the metallization component Ti and minor dopant As in this particular device, were successfully extracted by PCA. Finally, the 3D elemental distributions around the contact plug could be visualized by reconstruction from the tilt series of maps.

Zeiss ΣIGMA VP-FE-SEM User Guide

EPA Science Inventory

User guide for analyzing carbon based nanomaterials on a Zeiss Sigma microscope. The guide includes helpful steps for sample preparation and loading. Specific topics utilizing the scanning electron microscope are instrumentation startup and imagining. A variety of detectors in...

Porous Aluminum Oxide and Magnesium Oxide Films Using Organic Hydrogels as Structure Matrices

PubMed Central

Chen, Zimei

2018-01-01

We describe the synthesis of mesoporous Al2O3 and MgO layers on silicon wafer substrates by using poly(dimethylacrylamide) hydrogels as porogenic matrices. Hydrogel films are prepared by spreading the polymer through spin-coating, followed by photo-cross-linking and anchoring to the substrate surface. The metal oxides are obtained by swelling the hydrogels in the respective metal nitrate solutions and subsequent thermal conversion. Combustion of the hydrogel results in mesoporous metal oxide layers with thicknesses in the μm range and high specific surface areas up to 558 m2∙g−1. Materials are characterized by SEM, FIB ablation, EDX, and Kr physisorption porosimetry. PMID:29565802

Stratification and loading of fecal indicator bacteria (FIB) in a tidally muted urban salt marsh.

PubMed

Johnston, Karina K; Dorsey, John H; Saez, Jose A

2015-03-01

Stratification and loading of fecal indicator bacteria (FIB) were assessed in the main tidal channel of the Ballona Wetlands, an urban salt marsh receiving muted tidal flows, to (1) determine FIB concentration versus loading within the water column at differing tidal flows, (2) identify associations of FIB with other water quality parameters, and (3) compare wetland FIB concentrations to the adjacent estuary. Sampling was conducted four times during spring-tide events; samples were analyzed for FIB and turbidity (NTU) four times over a tidal cycle at pre-allocated depths, depending on the water level. Additional water quality parameters measured included temperature, salinity, oxygen, and pH. Loadings were calculated by integrating the stratified FIB concentrations with water column cross-sectional volumes corresponding to each depth. Enterococci and Escherichia coli were stratified both by concentration and loading, although these variables portrayed different patterns over a tidal cycle. Greatest concentrations occurred in surface to mid-strata levels, during flood tides when contaminated water flowed in from the estuary, and during ebb flows when sediments were suspended. Loading was greatest during flood flows and diminished during low tide periods. FIB concentrations within the estuary often were significantly greater than those within the wetland tide channel, supporting previous studies that the wetlands act as a sink for FIB. For public health water quality monitoring, these results indicate that more accurate estimates of FIB concentrations would be obtained by sampling a number of points within a water column rather than relying only on single surface samples.

Solid oxide fuel cell cathode infiltrate particle size control and oxygen surface exchange resistance determination

NASA Astrophysics Data System (ADS)

Burye, Theodore E.

Over the past decade, nano-sized Mixed Ionic Electronic Conducting (MIEC) -- micro-sized Ionic Conducting (IC) composite cathodes produced by the infiltration method have received much attention in the literature due to their low polarization resistance (RP) at intermediate (500-700°C) operating temperatures. Small infiltrated MIEC oxide nano-particle size and low intrinsic MIEC oxygen surface exchange resistance (Rs) have been two critical factors allowing these Nano-Micro-Composite Cathodes (NMCCs) to achieve high performance and/or low temperature operation. Unfortunately, previous studies have not found a reliable method to control or reduce infiltrated nano-particle size. In addition, controversy exists on the best MIEC infiltrate composition because: 1) Rs measurements on infiltrated MIEC particles are presently unavailable in the literature, and 2) bulk and thin film Rs measurements on nominally identical MIEC compositions often vary by up to 3 orders of magnitude. Here, two processing techniques, precursor nitrate solution desiccation and ceria oxide pre-infiltration, were developed to systematically produce a reduction in the average La0.6Sr0.4Co0.8Fe 0.2O3-delta (LSCF) infiltrated nano-particle size from 50 nm to 22 nm. This particle size reduction reduced the SOFC operating temperature, (defined as the temperature where RP=0.1 Ocm 2) from 650°C to 540°C. In addition, Rs values for infiltrated MIEC particles were determined for the first time through finite element modeling calculations on 3D Focused Ion Beam-Scanning Electron Microscope (FIB-SEM) reconstructions of electrochemically characterized infiltrated electrodes.

Development of new FIB technology for EUVL mask repair

NASA Astrophysics Data System (ADS)

Aramaki, Fumio; Ogawa, Takashi; Matsuda, Osamu; Kozakai, Tomokazu; Sugiyama, Yasuhiko; Oba, Hiroshi; Yasaka, Anto; Amano, Tsuyoshi; Shigemura, Hiroyuki; Suga, Osamu

2011-04-01

The next generation EUVL masks beyond hp15nm are difficult to repair for the current repair technologies including focused ion beam (FIB) and electron beam (EB) in view of the minimum repairable size. We developed a new FIB technology to repair EUVL masks. Conventional FIB use gallium ions (Ga+) generated by a liquid metal ion source (LMIS), but the new FIB uses hydrogen ions (H2+) generated by a gas field ion source (GFIS). The minimum reaction area of H2+ FIB is theoretically much smaller than that of EB. We investigated the repair performance of H2+ FIB. In the concrete, we evaluated image resolution, scan damage, etching rate, material selectivity of etching and actinic image of repaired area. The most important result is that there was no difference between the repaired area and the non-repaired one on actinic images. That result suggests that the H2+ GFIS technology is a promising candidate for the solution to repair the next generation EUVL masks beyond hp15nm.

Electron Microscopist | Center for Cancer Research

Cancer.gov

PROGRAM DESCRIPTION The Cancer Research Technology Program (CRTP) develops and implements emerging technology, cancer biology expertise and research capabilities to accomplish NCI research objectives. The CRTP is an outward-facing, multi-disciplinary hub purposed to enable the external cancer research community and provides dedicated support to NCI’s intramural Center for Cancer Research (CCR). The dedicated units provide electron microscopy, protein characterization, protein expression, optical microscopy and genetics. These research efforts are an integral part of CCR at the Frederick National Laboratory for Cancer Research (FNLCR). CRTP scientists also work collaboratively with intramural NCI investigators to provide research technologies and expertise. KEY ROLES/RESPONSIBILITIES - THIS POSITION IS CONTINGENT UPON FUNDING APPROVAL The Electron Microscopist will: Operate ultramicrotomes (Leica) and other instrumentation related to the preparation of embedded samples for EM (TEM and SEM) Operate TEM microscopes, (specifically Hitachi, FEI T20 and FEI T12) as well as SEM microscopes (Hitachi); task will include loading samples, screening, and performing data collection for a variety of samples: from cells to proteins Manage maintenance for the TEM and SEM microscopes Provide technical advice to investigators on sample preparation and data collection

SEM-microphotogrammetry, a new take on an old method for generating high-resolution 3D models from SEM images.

PubMed

Ball, A D; Job, P A; Walker, A E L

2017-08-01

The method we present here uses a scanning electron microscope programmed via macros to automatically capture dozens of images at suitable angles to generate accurate, detailed three-dimensional (3D) surface models with micron-scale resolution. We demonstrate that it is possible to use these Scanning Electron Microscope (SEM) images in conjunction with commercially available software originally developed for photogrammetry reconstructions from Digital Single Lens Reflex (DSLR) cameras and to reconstruct 3D models of the specimen. These 3D models can then be exported as polygon meshes and eventually 3D printed. This technique offers the potential to obtain data suitable to reconstruct very tiny features (e.g. diatoms, butterfly scales and mineral fabrics) at nanometre resolution. Ultimately, we foresee this as being a useful tool for better understanding spatial relationships at very high resolution. However, our motivation is also to use it to produce 3D models to be used in public outreach events and exhibitions, especially for the blind or partially sighted. © 2017 The Authors Journal of Microscopy © 2017 Royal Microscopical Society.

The PC9A Filter Screening Tool

DTIC Science & Technology

2016-02-01

conjunction with an optical microscope for identification of other important debris such as glass beads. The FST has now been installed at RAAF East...conservative screening limits need to be sent for detailed laboratory analysis. Laboratory analysis has traditionally involved a manual microscopic ...Electron Microscope with Energy Dispersive Spectroscopy (SEM EDS) to determine the composition and likely source. The Engine Maintenance Manual

Contact detection for nanomanipulation in a scanning electron microscope.

PubMed

Ru, Changhai; To, Steve

2012-07-01

Nanomanipulation systems require accurate knowledge of the end-effector position in all three spatial coordinates, XYZ, for reliable manipulation of nanostructures. Although the images acquired by a scanning electron microscope (SEM) provide high resolution XY information, the lack of depth information in the Z-direction makes 3D nanomanipulation time-consuming. Existing approaches for contact detection of end-effectors inside SEM typically utilize fragile touch sensors that are difficult to integrate into a nanomanipulation system. This paper presents a method for determining the contact between an end-effector and a target surface during nanomanipulation inside SEM, purely based on the processing of SEM images. A depth-from-focus method is used in the fast approach of the end-effector to the substrate, followed by fine contact detection. Experimental results demonstrate that the contact detection approach is capable of achieving an accuracy of 21.5 nm at 50,000× magnification while inducing little end-effector damage. Copyright © 2012 Elsevier B.V. All rights reserved.

Does Incorporating Change in APRI or FIB-4 Indices Over Time Improve the Accuracy of a Single Index for Identifying Liver Fibrosis in Persons With Chronic Hepatitis C Virus Infection?

PubMed

Gounder, Prabhu P; Haering, Celia; Bruden, Dana J T; Townshend-Bulson, Lisa; Simons, Brenna C; Spradling, Philip R; McMahon, Brian J

2018-01-01

The aspartate aminotransferase-to-platelet ratio index (APRI) and a fibrosis index calculated using platelets (FIB-4) have been proposed as noninvasive markers of liver fibrosis. To determine APRI/FIB-4 accuracy for predicting histologic liver fibrosis and evaluate whether incorporating change in index improves test accuracy in hepatitis C virus (HCV)-infected Alaska Native persons. Using liver histology as the gold standard, we determined the test characteristics of APRI to predict Metavir ≥F2 fibrosis and FIB-4 to predict Metavir ≥F3 fibrosis. Index discrimination was measured as the area under the receiver operator characteristic curve. We fit a logistic regression model to determine whether incorporating change in APRI/FIB-4 over time improved index discrimination. Among 283 participants, 46% were female, 48% had a body mass index >30, 11% had diabetes mellitus, 8% reported current heavy alcohol use. Participants were infected with HCV genotypes 1 (68%), 2 (17%), or 3 (15%). On liver histology, 30% of study participants had ≥F2 fibrosis and 15% had ≥F3 fibrosis. The positive predictive value of an APRI>1.5/FIB-4>3.25 for identifying fibrosis was 77%/78%. The negative predictive value of an APRI<0.5/FIB-4<1.45 was 91%/87%. The area under the receiver operator characteristic curve of an APRI/FIB-4 for identifying fibrosis was 0.82/0.84. Incorporating change in APRI/FIB-4 did not improve index discrimination. The accuracy of APRI/FIB-4 for identifying liver fibrosis in HCV-infected Alaska Native persons is similar to that reported in other populations and could help prioritize patients for treatment living in areas without access to liver biopsy. Change in APRI/FIB-4 was not predictive of degree of fibrosis.

NEXAFS Study of the Annealing Effect on the Local Structure of FIB-CVD DLC

DOE Office of Scientific and Technical Information (OSTI.GOV)

Saikubo, Akihiko; Kato, Yuri; Igaki, Jun-ya

2007-01-19

Annealing effect on the local structure of diamond like carbon (DLC) formed by focused ion beam-chemical vapor deposition (FIB-CVD) was investigated by the measurement of near edge x-ray absorption fine structure (NEXAFS) and energy dispersive x-ray (EDX) spectra. Carbon K edge absorption NEXAFS spectrum of FIB-CVD DLC was measured in the energy range of 275-320 eV. In order to obtain the information on the location of the gallium in the depth direction, incidence angle dependence of NEXAFS spectrum was measured in the incident angle range from 0 deg. to 60 deg. . The peak intensity corresponding to the resonance transitionmore » of 1s{yields}{sigma}* originating from carbon-gallium increased from the FIB-CVD DLC annealed at 200 deg. C to the FIB-CVD DLC annealed at 400 deg. C and decreased from that at 400 deg. C to that at 600 deg. C. Especially, the intensity of this peak remarkably enhanced in the NEXAFS spectrum of the FIB-CVD DLC annealed at 400 deg. C at the incident angle of 60 deg. . On the contrary, the peak intensity corresponding to the resonance transition of 1s{yields}{pi}* originating from carbon double bonding of emission spectrum decreased from the FIB-CVD DLC annealed at 200 deg. C to that at 400 deg. C and increased from that at 400 deg. C to that at 600 deg. C. Gallium concentration in the FIB-CVD DLC decreased from {approx_equal}2.2% of the as-deposited FIB-CVD DLC to {approx_equal}1.5% of the FIB-CVD DLC annealed at 600 deg. C from the elementary analysis using EDX. Both experimental results indicated that gallium atom departed from FIB-CVD DLC by annealing at the temperature of 600 deg. C.« less

HIV Mono-infection Is Associated With FIB-4 – A Noninvasive Index of Liver Fibrosis – in Women

PubMed Central

Welge, Jeffrey A.; Taylor, Lynn E.; Mayer, Kenneth H.; Klein, Robert S.; Celentano, David D.; Jamieson, Denise J.; Gardner, Lytt; Sherman, Kenneth E.

2011-01-01

Background. FIB-4 represents a noninvasive, composite index that is a validated measure of hepatic fibrosis, which is an important indicator of liver disease. To date, there are limited data regarding hepatic fibrosis in women. Methods. FIB-4 was evaluated in a cohort of 1227 women, and associations were evaluated in univariate and multivariate regression models among 4 groups of subjects classified by their human immunodeficiency virus (HIV) and hepatitis C virus (HCV) infection status. Results. The median FIB-4 scores were 0.60 in HIV-/HCV- women, 0.83 in HIV-/HCV+ women, 0.86 in HIV+/HCV- women, and 1.30 in HIV+/HCV+ women. In the HIV/HCV co-infected group, multivariate analysis showed that CD4+ cell count and albumin level were negatively associated with FIB-4 (P <.0001), whereas antiretroviral therapy (ART) was positively associated with FIB-4 score (P =.0008). For the HIV mono-infected group, multivariate analysis showed that CD4+ cell count (P <.0001) and albumin level (P =.0019) were negatively correlated with FIB-4 score, ART was positively associated with FIB-4 score (P =.0008), and plasma HIV RNA level was marginally associated with FIB-4 score (P =.080). In 72 HIV mono-infected women who were also hepatitis B surface antigen negative, ART naive, and reported no recent alcohol intake, plasma HIV RNA level was associated with increased FIB-4 score (P =.030). Conclusions. HIV RNA level was associated with increased FIB-4 score in the absence of hepatitis B, hepatitis C, ART, or alcohol use, suggesting a potential relationship between HIV infection and hepatic fibrosis in vivo. A better understanding of the various demographic and virologic variables that contribute to hepatic fibrosis may lead to more effective treatment of HIV infection and its co-morbid conditions. PMID:21248367

Adaptive noise Wiener filter for scanning electron microscope imaging system.

PubMed

Sim, K S; Teh, V; Nia, M E

2016-01-01

Noise on scanning electron microscope (SEM) images is studied. Gaussian noise is the most common type of noise in SEM image. We developed a new noise reduction filter based on the Wiener filter. We compared the performance of this new filter namely adaptive noise Wiener (ANW) filter, with four common existing filters as well as average filter, median filter, Gaussian smoothing filter and the Wiener filter. Based on the experiments results the proposed new filter has better performance on different noise variance comparing to the other existing noise removal filters in the experiments. © Wiley Periodicals, Inc.

Dynamic-scanning-electron-microscope study of friction and wear

NASA Technical Reports Server (NTRS)

Brainard, W. A.; Buckley, D. H.

1974-01-01

A friction and wear apparatus was built into a real time scanning electron microscope (SEM). The apparatus and SEM comprise a system which provides the capability of performing dynamic friction and wear experiments in situ. When the system is used in conjunction with dispersive X-ray analysis, a wide range of information on the wearing process can be obtained. The type of wear and variation with speed, load, and time can be investigated. The source, size, and distribution of wear particles can be determined and metallic transferal observed. Some typical results obtained with aluminum, copper, and iron specimens are given.

FIB-4 and imaging for measuring fibrosis in hepatitis C virus.

PubMed

Turner, Barbara J; Liang, Yuanyuan; Singal, Amit G

2017-02-01

Noninvasive measures are widely used to assess fibrosis and may be used to prioritize hepatitis C virus (HCV) treatment. We examined risks for likely fibrosis in patients with chronic HCV infection using fibrosis-4 (FIB-4) and imaging. A HCV screening program diagnosed chronic HCV in patients born from 1945 to 1965 admitted in a safety net hospital. Likely fibrosis was based on FIB-4 (≥1.45) alone or combined with imaging interpreted as fibrosis or cirrhosis. Logistic regression was used to calculate adjusted odds ratios (AORs) for demographic, clinical, and insurance factors associated with each outcome. Using multiple linear regression among patients with likely fibrosis, we examined associations with higher Model for End-Stage Liver Disease (MELD) scores. Using FIB-4 alone, 57% (83/146) of patients had likely fibrosis versus 43% (63/148) using FIB-4 plus imaging. Obesity/overweight and Hispanic ethnicity had over three-fold to four-fold higher AORs for fibrosis, respectively, based on FIB-4 plus imaging, but both AORs were only two-fold greater with FIB-4 alone. Being uninsured was significantly associated with fibrosis based on FIB-4 alone [AOR=2.40 (95% confidence interval 1.01-5.70)] but not with imaging. Heavy alcohol use and older age were associated with higher AORs of fibrosis with both measures (all P<0.004). MELD scores were ∼3 points higher for uninsured patients, regardless of measure (both P<0.05). Using FIB-4 plus imaging to identify fibrosis in chronic HCV, higher risks are seen for Hispanics and overweight/obese individuals than using FIB-4 alone. Higher MELD scores at diagnosis for the uninsured indicate delayed access to care.

Triple point fcc-hcp-liquid in the Fe phase diagram determined by in-situ XANES diagnostic and post-mortem XRD and FIB-SEM analysis.

NASA Astrophysics Data System (ADS)

Morard, G.; Boccato, S.; Rosa, A. D.; Anzellini, S.; Miozzi Ferrini, F.; Laura, H.; Garbarino, G.; Harmand, M.; Guyot, F. J.; Boulard, E.; Kantor, I.; Irifune, T.; Torchio, R.

2017-12-01

Iron is the main constituent of planetary cores. Studying its phase diagram under high pressure is necessary to constrain properties of planetary interiors, and to model key parameters such as the generation of magnetic field. Though, strong controversy on the melting curve of pure Fe still remains. Recently, Aquilanti et al, (PNAS, 2015) reported a Fe melting curved based on XANES measurements which is in open disagreement with previous X-ray diffraction results (Anzellini et al, Science, 2013). Discrepancies in the melting temperature exceed several hundred degrees close to Mbar pressures, which may be related to differences in temperature measurement techniques, melting diagnostics, or to chemical reactions of the sample with the surrounding medium. We therefore performed new in situ high P/T XANES experiments on pure Fe (up to 115 GPa and 4000 K) at the ESRF beamline ID24, combining the energy dispersive absorption set up with laser heated diamond anvil cells. X-ray diffraction maps were collected from all recovered samples in order to identify and characterize laser-heated spots. The XANES melting criterion was further cross checked by analyzing the recovered sample textures using FIB cutting techniques and SEM imaging. We found systematically that low melting temperatures are related to the presence of Fe3C, implying that in those cases chemical reactions occurred during heating resulting in carbon contamination from the diamonds. These low melting points fall onto the melting line reported by Aquilanti et al, (2015). Uncontaminated points are in agreement with the melting curve of Anzellini et al, (2013) within their uncertainties. Moreover, this data set allowed us to refine the location of the triple point in the Fe phase diagram at 105 (±10) GPa and 3600 (±200) K, which may imply a small kink in the melting curve around this point. This refined Fe phase diagram could be then used to compute thermodynamic models for planetary cores.

Face-specific Replacement of Calcite by Amorphous Silica Nanoparticles

NASA Astrophysics Data System (ADS)

Liesegang, M.; Milke, R.; Neusser, G.; Mizaikoff, B.

2016-12-01

Amorphous silica, composed of nanoscale spheres, is an important biomineral, alteration product of silicate rocks on the Earth's surface, and precursor material for stable silicate minerals. Despite constant progress in silica sphere synthesis, fundamental knowledge of natural silica particle interaction and ordering processes leading to colloidal crystals is absent so far. To understand the formation pathways of silica spheres in a geologic environment, we investigated silicified Cretaceous mollusk shell pseudomorphs from Coober Pedy (South Australia) using focused ion beam (FIB)-SEM tomography, petrographic microscopy, µ-XRD, and EMPA. The shells consist of replaced calcite crystals (<2 mm) composed of ordered arrays of uniform, close-packed silica spheres 300 ± 10 nm in size. Concentric layered spheres composed of 40 nm-sized subparticles provide evidence that, at least in the final stage, particle aggregation was the major sphere growth mechanism. Silica sphere arrays in periodically changing orientations perfectly replicate polysynthetic twinning planes of calcite. FIB-SEM tomography shows that cubic closed-packed sphere arrangements preserve the twin lamellae, while the twin plane consists of a submicrometer layer of randomly ordered spheres and vacancies. To transfer crystallographic information from parent to product, the advancement of synchronized dissolution and precipitation fronts along lattice planes is essential. We assume that the volume-preserving replacement process proceeds via a face-specific dissolution-precipitation mechanism with intermediate subparticle aggregation and subsequent layer-by-layer deposition of spheres along a planar surface. Porosity created during the replacement reaction allows permanent fluid access to the propagating reaction interface. Fluid pH and ionic strength remain constant throughout the replacement process, permitting continuous silica nanoparticle formation and diffusion-limited colloid aggregation. Our study provides a natural example of the transformation of an atomic crystal to an amorphous, mesoscale ordered material; thus, links the research fields of natural colloidal crystal formation, carbonate-silica replacement, and crystallization by oriented particle aggregation (CPA).

Applications of Real Space Crystallography in Characterization of Dislocations in Geological Materials in a Scanning Electron Microscope (SEM)

NASA Astrophysics Data System (ADS)

Kaboli, S.; Burnley, P. C.

2017-12-01

Imaging and characterization of defects in crystalline materials is of significant importance in various disciplines including geoscience, materials science, and applied physics. Linear defects such as dislocations and planar defects such as twins and stacking faults, strongly influence many of the properties of crystalline materials and also reflect the conditions and degree of deformation. Dislocations have been conventionally imaged in thin foils in a transmission electron microscope (TEM). Since the development of field emission scanning electron microscopes (FE-SEM) with high gun brightness and small spot size, extensive efforts have been dedicated to the imaging and characterization of dislocations in semi-conductors using electron channeling contrast imaging (ECCI) in the SEM. The obvious advantages of using SEM over TEM include easier and non-destructive sample preparation and a large field of view enabling statistical examination of the density and distribution of dislocations and other defects. In this contribution, we extend this technique to geological materials and introduce the Real Space Crystallography methodology for imaging and complete characterization of dislocations based on bend contour contrast obtained by ECCI in FE-SEM. Bend contours map out the distortion in the crystal lattice across a deformed grain. The contrast of dislocations is maximum in the vicinity of bend contours where crystal planes diffract at small and positive deviations from the Bragg positions (as defined by Bragg's law of electron diffraction). Imaging is performed in a commercial FE-SEM equipped with a standard silicon photodiode backscattered (BSE) detector and an electron backscatter diffraction (EBSD) system for crystal orientation measurements. We demonstrate the practice of this technique in characterization of a number of geological materials in particular quartz, forsterite olivine and corundum, experimentally deformed at high pressure-temperature conditions. This new approach in microstructure characterization of deformed geologic materials in FE-SEM, without the use of etching or decoration techniques, has valuable applications to both experimentally deformed and naturally deformed specimens.

The FIB-4 score predicts postoperative short-term outcomes of hepatocellular carcinoma fulfilling the milan criteria.

PubMed

Dong, J; Xu, X-h; Ke, M-y; Xiang, J-x; Liu, W-y; Liu, X-m; Wang, B; Zhang, X-f; Lv, Y

2016-05-01

The fibrosis score 4 (FIB-4) score is a useful tool to determine the degree of hepatic fibrosis. Liver fibrosis and cirrhosis are well-known predictors of postoperative complications after hepatectomy. This study examined the impact of FIB-4 on postoperative short-term outcomes of patients with hepatocellular carcinoma (HCC). Three hundred and fifty patients undergoing hepatectomy for HCC between 2008 and 2013 were enrolled. The receiver operating characteristic (ROC) curve analysis was performed to determine the cutoff value of the FIB-4. Univariate and multivariate analysis was performed to identify the risk factors. The correlation of the preoperative FIB-4 value with clinicopathological parameters was examined. Postoperative complications were observed in 202 (57.7%) patients. The optimal cutoff value of the FIB-4 was set at 2.88 and 3.85 for postoperative complications and intraoperative blood loss respectively. It was also an independent prognostic factor for postoperative complications (hazard ratio [HR], 1.202; 95% CI, 1.076-1.344; P = 0.001) and intraoperative blood loss (HR, 1.196; 95% CI, 1.091-1.343; P < 0.001) by multivariate analysis. The FIB-4 was significantly correlated with age, liver function, coagulation function, blood loss, intraoperative blood transfusion (all P < 0.05). Preoperative FIB-4 is a useful index to predict postoperative outcomes in patients with HCC. The FIB-4 should be assessed routinely for hepatocellular carcinoma patients. Copyright © 2016 Elsevier Ltd. All rights reserved.

3D lattice distortions and defect structures in ion-implanted nano-crystals

PubMed Central

Hofmann, Felix; Tarleton, Edmund; Harder, Ross J.; Phillips, Nicholas W.; Ma, Pui-Wai; Clark, Jesse N.; Robinson, Ian K.; Abbey, Brian; Liu, Wenjun; Beck, Christian E.

2017-01-01

Focussed Ion Beam (FIB) milling is a mainstay of nano-scale machining. By manipulating a tightly focussed beam of energetic ions, often gallium (Ga+), FIB can sculpt nanostructures via localised sputtering. This ability to cut solid matter on the nano-scale revolutionised sample preparation across the life, earth and materials sciences. Despite its widespread usage, detailed understanding of the FIB-induced structural damage, intrinsic to the technique, remains elusive. Here we examine the defects caused by FIB in initially pristine objects. Using Bragg Coherent X-ray Diffraction Imaging (BCDI), we are able to spatially-resolve the full lattice strain tensor in FIB-milled gold nano-crystals. We find that every use of FIB causes large lattice distortions. Even very low ion doses, typical of FIB imaging and previously thought negligible, have a dramatic effect. Our results are consistent with a damage microstructure dominated by vacancies, highlighting the importance of free-surfaces in determining which defects are retained. At larger ion fluences, used during FIB-milling, we observe an extended dislocation network that causes stresses far beyond the bulk tensile strength of gold. These observations provide new fundamental insight into the nature of the damage created and the defects that lead to a surprisingly inhomogeneous morphology. PMID:28383028

3D lattice distortions and defect structures in ion-implanted nano-crystals.

PubMed

Hofmann, Felix; Tarleton, Edmund; Harder, Ross J; Phillips, Nicholas W; Ma, Pui-Wai; Clark, Jesse N; Robinson, Ian K; Abbey, Brian; Liu, Wenjun; Beck, Christian E

2017-04-06

Focussed Ion Beam (FIB) milling is a mainstay of nano-scale machining. By manipulating a tightly focussed beam of energetic ions, often gallium (Ga + ), FIB can sculpt nanostructures via localised sputtering. This ability to cut solid matter on the nano-scale revolutionised sample preparation across the life, earth and materials sciences. Despite its widespread usage, detailed understanding of the FIB-induced structural damage, intrinsic to the technique, remains elusive. Here we examine the defects caused by FIB in initially pristine objects. Using Bragg Coherent X-ray Diffraction Imaging (BCDI), we are able to spatially-resolve the full lattice strain tensor in FIB-milled gold nano-crystals. We find that every use of FIB causes large lattice distortions. Even very low ion doses, typical of FIB imaging and previously thought negligible, have a dramatic effect. Our results are consistent with a damage microstructure dominated by vacancies, highlighting the importance of free-surfaces in determining which defects are retained. At larger ion fluences, used during FIB-milling, we observe an extended dislocation network that causes stresses far beyond the bulk tensile strength of gold. These observations provide new fundamental insight into the nature of the damage created and the defects that lead to a surprisingly inhomogeneous morphology.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cooke, Gary A.; Pestovich, John A.; Huber, Heinz J.

This report presents the results for solid phase characterization (SPC) of solid samples removed from tank 241-C-108 (C-108) on August 12-13,2012, using the off-riser sampler. Samples were received at the 222-S Laboratory on August 13 and were described and photographed. The SPC analyses that were performed include scanning electron microscopy (SEM) using the ASPEX(R)l scanning electron microscope, X-ray diffraction (XRD) using the Rigaku(R) 2 MiniFlex X-ray diffractometer, and polarized light microscopy (PLM) using the Nikon(R) 3 Eclipse Pol optical microscope. The SEM is equipped with an energy dispersive X-ray spectrometer (EDS) to provide chemical information. Gary A. Cooke conducted themore » SEM analysis, John A. Pestovich performed the XRD analysis, and Dr. Heinz J. Huber performed the PLM examination. The results of these analyses are presented here.« less

Quantitative Analysis of Three-dimensional Microstructure of Li-ion Battery Electrodes

NASA Astrophysics Data System (ADS)

Liu, Zhao

Li-ion batteries (LIBs) have attracted considerable attention in the past two decades due to their widespread applications in portable electronics, and their growing use in electric vehicles and large-scale grid storage. Increasing battery energy density and powder density while maintaining long life, along with battery safety, are the biggest challenges that limit their further development. Various approaches with materials and chemistry have been employed to improve performance. However, one less-studied aspect that also impacts performance is the electrode microstructure. In particular, three-dimensional (3D) electrode microstructural data for LIB electrodes, which were not widely available prior to this thesis, can provide important input for understanding and improving LIB performance. The focus of this thesis is to apply 3D tomographic techniques, together with electrochemical performance data, to obtain LIB microstructure-performance correlations. Two advanced 3D structural analysis techniques, focused ion beam-scanning electron microscopy (FIB-SEM) and transmission X-ray microscopy (TXM) nanotomography, are used to quantify LIB electrode microstructure. 3D characterization of LIB electrode microstructure is used to obtain a deeper understanding of mechanisms that limit LIB performance. Microstructural characterization before and after cycling is used to explore capacity loss mechanisms. It is hoped that the results can guide electrode microstructures design to improve performance and stability. Two types of commercial electrodes, LiCoO2 and LiCoO 2/Li(Ni1/3Mn1/3Co1/3)O2, are studied using FIB-SEM and TXM. Both methods were found to be applicable to quantifying the oxide particle microstructure, including volume fraction, surface area, and particle size distribution, and results agreed well. However, structural inhomogeneity found in these commercial samples, limited the capability to resolve microstructural changes during cycling. In order to also quantify carbonaceous phases in the electrodes, which strongly correlate with LIB transport properties, a three-phase FIB-SEM method was developed where silicone resin was infiltrated into electrode pores, providing good image contrast with the carbon particles. Structural parameters including phase connectivity and tortuosity are quantified for commercial LiCoO 2 and laboratory-made LiFePO4 electrodes to help understand the transport process in these electrodes. For LiCoO2 electrodes, a heterogeneous tortuosity distribution observed in the electrolyte phase may result in inhomogeneous charge/discharge states, and consequently cause battery degradation. For LiFePO4 electrodes, highly percolated and less tortuous carbon found in a templated electrode explain its better high-C-rate performance. Finally, laboratory-made LiMn2O4 electrodes were electrochemically cycled with different operation parameters, including cycle number, temperature, and operating voltage. Quantitative analyses on 3D TXM data sets indicate particle fracture, mainly due to tetragonal to cubic phase transformations induced by the Jahn-Teller effect, resulting in electrode degradation. Moreover, high temperature operation is found to enhance active material dissolution and can also accelerate cell degradation. This ex-situ method, which combines electrochemical cycling and statistical analysis, proved to be an effective approach to provide insight for the interpretation of complex mechanical and electrochemical interactions within the electrodes.

Microcellular nanocomposite injection molding process

Treesearch

Mingjun Yuan; Lih-Sheng Turng; Rick Spindler; Daniel Caulfield; Chris Hunt

2003-01-01

This study aims to explore the processing benefits and property improvements of combining nanocomposites with microcellular injection molding. The molded parts produced based on the Design of Experiments (DOE) matrices were subjected to tensile testing, impact testing, and Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM), Dynamic Mechanical...

Atmospheric scanning electron microscope for correlative microscopy.

PubMed

Morrison, Ian E G; Dennison, Clare L; Nishiyama, Hidetoshi; Suga, Mitsuo; Sato, Chikara; Yarwood, Andrew; O'Toole, Peter J

2012-01-01

The JEOL ClairScope is the first truly correlative scanning electron and optical microscope. An inverted scanning electron microscope (SEM) column allows electron images of wet samples to be obtained in ambient conditions in a biological culture dish, via a silicon nitride film window in the base. A standard inverted optical microscope positioned above the dish holder can be used to take reflected light and epifluorescence images of the same sample, under atmospheric conditions that permit biochemical modifications. For SEM, the open dish allows successive staining operations to be performed without moving the holder. The standard optical color camera used for fluorescence imaging can be exchanged for a high-sensitivity monochrome camera to detect low-intensity fluorescence signals, and also cathodoluminescence emission from nanophosphor particles. If these particles are applied to the sample at a suitable density, they can greatly assist the task of perfecting the correlation between the optical and electron images. Copyright © 2012 Elsevier Inc. All rights reserved.

Automated radiosynthesis of no-carrier-added 4-[18F]fluoroiodobenzene: a versatile building block in 18F radiochemistry.

PubMed

Way, Jenilee Dawn; Wuest, Frank

2014-02-01

4-[18F]Fluoroiodobenzene ([18F]FIB) is a versatile building block in 18F radiochemistry used in various transition metal-mediated C-C and C-N cross-coupling reactions and [18F]fluoroarylation reactions. Various synthesis routes have been described for the preparation of [18F]FIB. However, to date, no automated synthesis of [18F]FIB has been reported to allow access to larger amounts of [18F]FIB in high radiochemical and chemical purity. Herein, we describe an automated synthesis of no-carrier-added [18F]FIB on a GE TRACERlab™ FX automated synthesis unit starting from commercially available(4-iodophenyl)diphenylsulfonium triflate as the labelling precursor. [18F]FIB was prepared in high radiochemical yields of 89 ± 10% (decay-corrected, n = 7) within 60 min, including HPLC purification. The radiochemical purity exceeded 95%, and specific activity was greater than 40 GBq/μmol. Typically, from an experiment, 6.4 GBq of [18F]FIB could be obtained starting from 10.4 GBq of [18F]fluoride.

Multi-environment Nanocalorimeter with Electrical Contacts for Use in the Scanning Electron Microscope.

PubMed

Yi, Feng; Stevanovic, Ana; Osborn, William A; Kolmakov, A; LaVan, David A

2017-11-01

We have developed a versatile nanocalorimeter sensor which allows imaging and electrical measurements of samples under different gaseous environments using the scanning electron microscope (SEM) and can simultaneously measure the sample temperature and associated heat of reaction. This new sensor consists of four independent heating/sensing elements for nanocalorimetry and eight electrodes for electrical measurements, all mounted on a 50 nm thick, 250 μm × 250 μm suspended silicon nitride membrane. This membrane is highly electron transparent and mechanically robust enabling in situ SEM observation under realistic temperatures, environmental conditions and pressures up to one atmosphere. To demonstrate this new capability, we report here on 1) in situ SEM-nanocalorimetry study of melting and solidification of polyethylene oxide, 2) the temperature dependence of conductivity of a nanowire; 3) the electron beam induced current measurements (EBID) of a nanowire in vacuum and air. Furthermore, the sensor is easily adaptable to operate in liquid environment and is compatible with most existing SEM. This versatile platform couples nanocalorimetry with in situ SEM imaging under various gaseous and liquid environments and is applicable to materials research, nanotechnology, energy, catalysis and biomedical applications.

Wear at the titanium-titanium and the titanium-zirconia implant-abutment interface: a comparative in vitro study.

PubMed

Stimmelmayr, Michael; Edelhoff, Daniel; Güth, Jan-Frederik; Erdelt, Kurt; Happe, Arndt; Beuer, Florian

2012-12-01

The purpose of this study was to determine and measure the wear of the interface between titanium implants and one-piece zirconia abutments in comparison to titanium abutments. 6 implants were secured into epoxy resin blocks. The implant interface of these implants and 6 corresponding abutments (group Zr: three one-piece zirconia abutments; group Ti: three titanium abutments) were examined by a microscope and scanning electron micrograph (SEM). Also the implants and the abutments were scanned by 3D-Micro Computer Tomography (CT). The abutments were connected to the implants and cyclically loaded with 1,200,000 cycles at 100N in a two-axis fatigue testing machine. Afterwards, all specimens were unscrewed and the implants and abutments again were scanned by microscope, SEM and CT. The microscope and SEM images were compared, the CT data were superimposed and the wear was calculated by inspection software. The statistical analysis was carried out with an unpaired t-test. Abutment fracture or screw loosening was not observed during cyclical loading. Comparing the microscope and SEM images more wear was observed on the implants connected to zirconia abutments. The maximum wear on the implant shoulder calculated by the inspection software was 10.2μm for group Zr, and 0.7μm for group Ti. The influence of the abutment material on the measured wear was statistically significant (p≤0.001; Levene-test). Titanium implants showed higher wear at the implant interface following cyclic loading when connected to one-piece zirconia implant abutments compared to titanium abutments. The clinical relevance is not clear; hence damage of the internal implant connection could result in prosthetic failures up to the need of implant removal. Copyright © 2012 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Comparative study viruses with computer-aided phase microscope AIRYSCAN

NASA Astrophysics Data System (ADS)

Tychinsky, Vladimir P.; Koufal, Georgy E.; Perevedentseva, Elena V.; Vyshenskaia, Tatiana V.

1996-12-01

Traditionally viruses are studied with scanning electron microscopy (SEM) after complicated procedure of sample preparation without the possibility to study it under natural conditions. We obtained images of viruses (Vaccinia virus, Rotavirus) and rickettsias (Rickettsia provazekii, Coxiella burnetti) in native state with computer-aided phase microscope airyscan -- the interference microscope of Linnik layout with phase modulation of the reference wave with dissector image tube as coordinate-sensitive photodetector and computer processing of phase image. A light source was the He-Ne laser. The main result is coincidence of dimensions and shape of phase images with available information concerning their morphology obtained with SEM and other methods. The fine structure of surface and nuclei is observed. This method may be applied for virus recognition and express identification, investigation of virus structure and the analysis of cell-virus interaction.

Microstructures and electrochemical behaviors of the friction stir welding dissimilar weld.

PubMed

Shen, Changbin; Zhang, Jiayan; Ge, Jiping

2011-06-01

By using optical microscope, the microstructures of 5083/6082 friction stir welding (FSW) weld and parent materials were analyzed. Meanwhile, at ambient temperature and in 0.2 mol/L NaHS03 and 0.6 mol/L NaCl solutionby gravimetric test, potentiodynamic polarization curve test, electrochemical impedance spectra (EIS) and scanning electron microscope (SEM) observation, the electrochemical behavior of 5083/6082 friction stir welding weld and parent materials were comparatively investigated by gravimetric test, potentiodynamic polarization curve test, electrochemical impedance spectra (EIS) and scanning electron microscope (SEM) observation. The results indicated that at given processing parameters, the anti-corrosion property of the dissimilar weld was superior to those of the 5083 and 6082 parent materials. Copyright © 2011 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.

Qualitative and quantitative interpretation of SEM image using digital image processing.

PubMed

Saladra, Dawid; Kopernik, Magdalena

2016-10-01

The aim of the this study is improvement of qualitative and quantitative analysis of scanning electron microscope micrographs by development of computer program, which enables automatic crack analysis of scanning electron microscopy (SEM) micrographs. Micromechanical tests of pneumatic ventricular assist devices result in a large number of micrographs. Therefore, the analysis must be automatic. Tests for athrombogenic titanium nitride/gold coatings deposited on polymeric substrates (Bionate II) are performed. These tests include microshear, microtension and fatigue analysis. Anisotropic surface defects observed in the SEM micrographs require support for qualitative and quantitative interpretation. Improvement of qualitative analysis of scanning electron microscope images was achieved by a set of computational tools that includes binarization, simplified expanding, expanding, simple image statistic thresholding, the filters Laplacian 1, and Laplacian 2, Otsu and reverse binarization. Several modifications of the known image processing techniques and combinations of the selected image processing techniques were applied. The introduced quantitative analysis of digital scanning electron microscope images enables computation of stereological parameters such as area, crack angle, crack length, and total crack length per unit area. This study also compares the functionality of the developed computer program of digital image processing with existing applications. The described pre- and postprocessing may be helpful in scanning electron microscopy and transmission electron microscopy surface investigations. © 2016 The Authors Journal of Microscopy © 2016 Royal Microscopical Society.

Site-Specific Preparation of Intact Solid–Liquid Interfaces by Label-Free In Situ Localization and Cryo-Focused Ion Beam Lift-Out

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zachman, Michael J.; Asenath-Smith, Emily; Estroff, Lara A.

Abstract Scanning transmission electron microscopy (STEM) allows atomic scale characterization of solid–solid interfaces, but has seen limited applications to solid–liquid interfaces due to the volatility of liquids in the microscope vacuum. Although cryo-electron microscopy is routinely used to characterize hydrated samples stabilized by rapid freezing, sample thinning is required to access the internal interfaces of thicker specimens. Here, we adapt cryo-focused ion beam (FIB) “lift-out,” a technique recently developed for biological specimens, to prepare intact internal solid–liquid interfaces for high-resolution structural and chemical analysis by cryo-STEM. To guide the milling process we introduce a label-freein situmethod of localizing subsurface structuresmore » in suitable materials by energy dispersive X-ray spectroscopy (EDX). Monte Carlo simulations are performed to evaluate the depth-probing capability of the technique, and show good qualitative agreement with experiment. We also detail procedures to produce homogeneously thin lamellae, which enable nanoscale structural, elemental, and chemical analysis of intact solid–liquid interfaces by analytical cryo-STEM. This work demonstrates the potential of cryo-FIB lift-out and cryo-STEM for understanding physical and chemical processes at solid–liquid interfaces.« less

Meteorological effects on the levels of fecal indicator bacteria in an urban stream: a modeling approach.

PubMed

Cho, Kyung Hwa; Cha, Sung Min; Kang, Joo-Hyon; Lee, Seung Won; Park, Yongeun; Kim, Jung-Woo; Kim, Joon Ha

2010-04-01

Gwangju Creek (GJC) in Korea, which drains a highly urbanized watershed, has suffered from substantial fecal contamination, thereby limiting the beneficial use of the water in addition to threatening public health. In this study, to quantitatively estimate the sinks and sources of fecal indicator bacteria (FIB) in GJC under varying meteorological conditions, two FIB (i.e., Escherichia coli and enterococci bacteria) were monitored hourly for 24h periods during both wet and dry weather conditions at four sites along GJC, and the collected data was subsequently used to develop a spatiotemporal FIB prediction model. The monitoring data revealed that storm washoff and irradiational die-off by sunlight are the two key processes controlling FIB populations in wet and dry weather, respectively. FIB populations significantly increased during precipitation, with greater concentrations occurring at higher rainfall intensity. During dry weather, FIB populations decreased in the presence of sunlight in daytime but quickly recovered at nighttime due to continuous point-source inputs. In this way, the contributions of the key processes (i.e., irradiational die-off by sunlight, settling, storm washoff, and resuspension) to the FIB levels in GJC under different meteorological conditions were quantitatively estimated using the developed model. The modeling results showed that the die-off by sunlight is the major sink of FIB during the daytime in dry weather with a minor contribution from the settling process. During wet weather, storm washoff and resuspension are equally important processes that are responsible for the substantial increase of FIB populations. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

Preparation and Characterization of Carbon Filaments

DTIC Science & Technology

1991-04-01

Kawasumi, "Whiskerization of Carbon Beads by Vapor Phase Growth of Carbon Fibers to Obtain Sea Urchin -Type Particles", Carbon 21, 89 (1983). 5) R.T.K...multiple fiber microstructure are possible on what appears to be a single fiber along the length of the fiber. However, without SEM micrographs, it is...180 minutes. Scanning Electron Microscopic ( SEM ) observations were cared out using P Philips series 505 SEM system, typically operating at an

High Resolution Fabrication of Interconnection Lines Using Picosecond Laser and Controlled Deposition of Gold Nanoparticles

NASA Astrophysics Data System (ADS)

Shahmoon, Asaf; Strauß, Johnnes; Zafri, Hadar; Schmidt, Michael; Zalevsky, Zeev

In this paper we present the fabrication procedure as well as the preliminary experimental results of a novel method for construction of high resolution nanometric interconnection lines. The fabrication procedure relies on a self-assembly process of gold nanoparticles at specific predetermined nanostructures. The nanostructures for the self-assembly process are based on the focused ion beam (FIB) or scanning electron beam (SEM) technology. The assembled nanoparticles are being illuminated using a picosecond laser with a wavelength of 532 nm. Different pulse energies have been investigated. The paper aimed at developing a novel and reliable process for fabrication of interconnection lines encompass three different disciplines, self-assembly of nanometric particles, optics and microelectronic.

Porosity characterization for heterogeneous shales using integrated multiscale microscopy

NASA Astrophysics Data System (ADS)

Rassouli, F.; Andrew, M.; Zoback, M. D.

2016-12-01

Pore size distribution analysis plays a critical role in gas storage capacity and fluid transport characterization of shales. Study of the diverse distribution of pore size and structure in such low permeably rocks is withheld by the lack of tools to visualize the microstructural properties of shale rocks. In this paper we try to use multiple techniques to investigate the full pore size range in different sample scales. Modern imaging techniques are combined with routine analytical investigations (x-ray diffraction, thin section analysis and mercury porosimetry) to describe pore size distribution of shale samples from Haynesville formation in East Texas to generate a more holistic understanding of the porosity structure in shales, ranging from standard core plug down to nm scales. Standard 1" diameter core plug samples were first imaged using a Versa 3D x-ray microscope at lower resolutions. Then we pick several regions of interest (ROIs) with various micro-features (such as micro-cracks and high organic matters) in the rock samples to run higher resolution CT scans using a non-destructive interior tomography scans. After this step, we cut the samples and drill 5 mm diameter cores out of the selected ROIs. Then we rescan the samples to measure porosity distribution of the 5 mm cores. We repeat this step for samples with diameter of 1 mm being cut out of the 5 mm cores using a laser cutting machine. After comparing the pore structure and distribution of the samples measured form micro-CT analysis, we move to nano-scale imaging to capture the ultra-fine pores within the shale samples. At this stage, the diameter of the 1 mm samples will be milled down to 70 microns using the laser beam. We scan these samples in a nano-CT Ultra x-ray microscope and calculate the porosity of the samples by image segmentation methods. Finally, we use images collected from focused ion beam scanning electron microscopy (FIB-SEM) to be able to compare the results of porosity measurements from all different imaging techniques. These multi-scale characterization techniques are then compared with traditional analytical techniques such as Mercury Porosimetry.

Distribution of Fecal Indicator Bacteria along the Malibu, California, Coastline

USGS Publications Warehouse

Izbicki, John

2011-01-01

Each year, over 550 million people visit California's public beaches. To protect beach-goers from exposure to waterborne disease, California state law requires water-quality monitoring for fecal indicator bacteria (FIB), such as enterococci and Escherichia coli (E. coli), at beaches having more than 50,000 yearly visitors. FIB are used to assess the microbiological quality of water because, although not typically disease causing, they are correlated with the occurrence of certain waterborne diseases. Tests show that FIB concentrations occasionally exceed U.S. Environmental Protection Agency (USEPA) public health standards for recreational water in Malibu Lagoon and at several Malibu beaches (Regional Water Quality Control Board, 2009). Scientists from the U.S. Geological Survey's (USGS) California Water Science Center are doing a study to identify the distribution and sources of FIB in coastal Malibu waters (fig. 1). The study methods were similar to those used in a study of FIB contamination on beaches in the Santa Barbara, California, area (Izbicki and others, 2009). This report describes the study approach and presents preliminary results used to evaluate the distribution and source of FIB in the Malibu area. Results of this study will help decision-makers address human health issues associated with FIB contamination in Malibu, and the methods used in this study can be used in other coastal areas affected by FIB contamination.

Long-term prognosis of patients with chronic hepatitis C who did not receive interferon-based therapy: causes of death and analysis based on the FIB-4 index.

PubMed

Tada, Toshifumi; Kumada, Takashi; Toyoda, Hidenori; Kiriyama, Seiki; Tanikawa, Makoto; Hisanaga, Yasuhiro; Kanamori, Akira; Kitabatake, Shusuke; Yama, Tsuyoki; Tanaka, Junko

2016-04-01

Interferon (IFN)-based therapy has been reported to reduce the liver-related mortality rate in patients with chronic hepatitis C virus (HCV) infection. However, predictors of survival and causes of death, including non-liver-related causes, have not been sufficiently investigated in chronic HCV patients who have not received IFN-based therapy. A total of 1723 patients with chronic HCV infection who were not treated with IFN-based therapy were enrolled. Survival from liver-related diseases and non-liver-related diseases and causes of death were analyzed on the basis of the fibrosis-4 (FIB-4) index, an index of liver fibrosis. The median follow-up duration was 10.3 years. Of 465 patients who died during the follow-up period, 48.4 % died of liver-related diseases; of the remainder, 51.6 % died of non-liver-related diseases. On the basis of FIB-4 index, the liver-related mortality rate increased as the FIB-4 index increased: 16.1 % in the FIB-4 index < 1.45 group, 36.7 % in the 1.45 ≤ FIB-4 index ≤ 3.25 group, and 58.7 % in the FIB-4 index > 3.25 group (p < 0.001). Conversely, the non-liver-related mortality rate decreased as the FIB-4 index increased: 83.9, 63.3, and 41.3 %, respectively (p = 0.001). In the multivariate analysis, a FIB-4 index greater than 3.25 was identified as a risk factor independently associated with both liver-related death (hazard ratio 13.020; 95 % confidence interval 4.155-40.770) and non-liver-related death (hazard ratio 1.667; 95 % confidence interval 1.188-2.340). Patients with chronic HCV infection and an elevated FIB-4 index may benefit from monitoring not only for the development of liver-related diseases but also for the development of non-liver-related diseases.

High liver fibrosis index FIB-4 is highly predictive of hepatocellular carcinoma in chronic hepatitis B carriers.

PubMed

Suh, Beomseok; Park, Sehhoon; Shin, Dong Wook; Yun, Jae Moon; Yang, Hyung-Kook; Yu, Su Jong; Shin, Cheong-Il; Kim, Jin-Soo; Ahn, Eunmi; Lee, Hyejin; Park, Jin Ho; Cho, BeLong

2015-04-01

Screening for hepatocellular carcinoma (HCC) is clinically important given that its early detection has remarkable survival benefits. We investigated the possible role of FIB-4, a recently developed noninvasive marker for liver fibrosis based on routine laboratory tests, as a clinical indicator for predicting future HCC among hepatitis B surface antigen (HBsAg) carriers. Our retrospective cohort study involved 986 Korean HBsAg carriers 40 years of age or older who visited Seoul National University Hospital for a health checkup. National medical service claims data were used to determine HCC incidence. Median follow-up time was 5.4 years (interquartile range: 4.4 years). Adjusted for age, sex, body mass index, smoking, alcohol, and antiviral medication for hepatitis B, compared to subjects with FIB-4 <1.25, subjects with 1.7≤ FIB-4 <2.4 showed an adjusted hazard ratio (aHR) of 4.57 (95% confidence interval [CI]: 1.50-13.92) and subjects with FIB-4 ≥2.4 showed an aHR of 21.34 (95% CI: 7.73-58.92) for HCC incidence. FIB-4 was shown to have incremental predictive value to ultrasonographic liver cirrhosis for HCC incidence (C-index: 0.701 vs. 0.831; P = 0.001). FIB-4 was also better predictive of HCC incidence, compared to that of ultrasonographic liver cirrhosis (C-index: 0.775 vs. 0.701; P = 0.040). High FIB-4 is a highly predictive risk factor for HCC incidence among Korean HBsAg carriers. FIB-4 is a promising, easily applicable, and cost-effective clinical tool in identifying a subpopulation of HBsAg carriers who are at heightened risk. Our study needs to be replicated in larger future studies on various ethnic groups; nonetheless, our study suggests that FIB-4 may play a valuable role in HCC screening among HBsAg carriers. © 2014 by the American Association for the Study of Liver Diseases.

Comparative genomic analysis and characterization of incompatibility group FIB plasmid encoded virulence factors of Salmonella enterica isolated from food sources.

PubMed

Khajanchi, Bijay K; Hasan, Nur A; Choi, Seon Young; Han, Jing; Zhao, Shaohua; Colwell, Rita R; Cerniglia, Carl E; Foley, Steven L

2017-08-02

The degree to which the chromosomal mediated iron acquisition system contributes to virulence of many bacterial pathogens is well defined. However, the functional roles of plasmid encoded iron acquisition systems, specifically Sit and aerobactin, have yet to be determined for Salmonella spp. In a recent study, Salmonella enterica strains isolated from different food sources were sequenced on the Illumina MiSeq platform and found to harbor the incompatibility group (Inc) FIB plasmid. In this study, we examined sequence diversity and the contribution of factors encoded on the IncFIB plasmid to the virulence of S. enterica. Whole genome sequences of seven S. enterica isolates were compared to genomes of serovars of S. enterica isolated from food, animal, and human sources. SeqSero analysis predicted that six strains were serovar Typhimurium and one was Heidelberg. Among the S. Typhimurium strains, single nucleotide polymorphism (SNP)-based phylogenetic analyses revealed that five of the isolates clustered as a single monophyletic S. Typhimurium subclade, while one of the other strains branched with S. Typhimurium from a bovine source. DNA sequence based phylogenetic diversity analyses showed that the IncFIB plasmid-encoded Sit and aerobactin iron acquisition systems are conserved among bacterial species including S. enterica. The IncFIB plasmid was transferred to an IncFIB plasmid deficient strain of S. enterica by conjugation. The transconjugant SE819::IncFIB persisted in human intestinal epithelial (Caco-2) cells at a higher rate than the recipient SE819. Genes of the Sit and aerobactin operons in the IncFIB plasmid were differentially expressed in iron-rich and iron-depleted growth media. Minimal sequence diversity was detected in the Sit and aerobactin operons in the IncFIB plasmids present among different bacterial species, including foodborne Salmonella strains. IncFIB plasmid encoded factors play a role during infection under low-iron conditions in host cells.

Focused Ion Beam Recovery of Hypervelocity Impact Residue in Experimental Craters on Metallic Foils

NASA Technical Reports Server (NTRS)

Graham, G. A.; Teslich, N.; Dai, Z. R.; Bradley, J. P.; Kearsley, A. T.; Horz, F.

2006-01-01

The Stardust sample return capsule will return to Earth in January 2006 with primitive debris collected from Comet 81P/Wild-2 during the fly-by encounter in 2004. In addition to the cometary particles embedded in low-density silica aerogel, there will be microcraters preserved in the Al foils (1100 series; 100 micrometers thick) that are wrapped around the sample tray assembly. Soda lime spheres (approximately 49 m in diameter) have been accelerated with a light-gas-gun into flight-grade Al foils at 6.35 km s(sup -1) to simulate the potential capture of cometary debris. The preserved crater penetrations have been analyzed using scanning electron microscopy (SEM) and x-ray energy dispersive spectroscopy (EDX) to locate and characterize remnants of the projectile material remaining within the craters. In addition, ion beam induced secondary electron imaging has proven particularly useful in identifying areas within the craters that contain residue material. Finally, high-precision focused ion beam (FIB) milling has been used to isolate and then extract an individual melt residue droplet from the interior wall of an impact penetration. This enabled further detailed elemental characterization, free from the background contamination of the Al foil substrate. The ability to recover pure melt residues using FIB will significantly extend the interpretations of the residue chemistry preserved in the Al foils returned by Stardust.

A Coordinated Focused Ion Beam/Ultramicrotomy Technique for Serial Sectioning of Hayabusa Particles and Other Returned Samples

NASA Technical Reports Server (NTRS)

Berger, E. L.; Keller, L. P.

2014-01-01

Recent sample return missions, such as NASA's Stardust mission to comet 81P/Wild 2 and JAXA's Hayabusa mission to asteroid 25143 Itokawa, have returned particulate samples (typically 5-50 µm) that pose tremendous challenges to coordinated analysis using a variety of nano- and micro-beam techniques. The ability to glean maximal information from individual particles has become increasingly important and depends critically on how the samples are prepared for analysis. This also holds true for other extraterrestrial materials, including interplanetary dust particles, micrometeorites and lunar regolith grains. Traditionally, particulate samples have been prepared using microtomy techniques (e.g., [1]). However, for hard mineral particles ?20 µm, microtome thin sections are compromised by severe chatter and sample loss. For these difficult samples, we have developed a hybrid technique that combines traditional ultramicrotomy with focused ion beam (FIB) techniques, allowing for the in situ investigation of grain surfaces and interiors. Using this method, we have increased the number of FIB-SEM prepared sections that can be recovered from a particle with dimensions on the order of tens of µms. These sections can be subsequently analyzed using a variety of electron beam techniques. Here, we demonstrate this sample preparation technique on individual lunar regolith grains in order to study their space-weathered surfaces. We plan to extend these efforts to analyses of individual Hayabusa samples.

The Effect of Molybdenum Substrate Oxidation on Molybdenum Splat Formation

NASA Astrophysics Data System (ADS)

Wang, Jun; Li, Chang-Jiu

2018-01-01

Disk splats are usually observed when the deposition temperature exceeds the transition temperature, whereas thick oxide layer will reduce the adhesion resulting from high deposition temperature. In present study, single molybdenum splats were deposited onto polished molybdenum substrates with different preheating processes to clarify the effect of surface oxidation on the splat formation. Three substrate samples experienced three different preheating processes in an argon atmosphere. Two samples were preheated to 350 and 550 °C, and another sample was cooled to 350 °C after it was preheated to 550 °C. The chemistry and compositions of substrate surface were examined by XPS. The cross sections of splats were prepared by focus ion beam (FIB) and then characterized by SEM. Nearly disk-shaped splat with small fingers in the periphery was observed on the sample preheated to 350 °C. A perfect disk-shape splat was deposited at 550 °C. With the sample on the substrate preheated to 350 °C (cooling down from 550 °C), flower-shaped splat exhibited a central core and discrete periphery detached by some voids. The results of peeling off splats by carbon tape and the morphology of FIB sampled cross sections indicated that no effective bonding formed at the splat-substrate interface for the substrate ever heated to 550 °C, due to the increasing content of MoO3 on the preheated molybdenum surface.

Unveiling the Mysteries of Mars with a Miniaturized Variable Pressure Scanning Electron Microscope (MVP-SEM)

NASA Technical Reports Server (NTRS)

Edmunson, J.; Gaskin, J. A.; Doloboff, I. J.

2017-01-01

Development of a miniaturized scanning electron microscope that will utilize the martian atmosphere to dissipate charge during analysis continues. This instrument is expected to be used on a future rover or lander to answer fundamental Mars science questions. To identify the most important questions, a survey was taken at the 47th Lunar and Planetary Science Conference (LPSC). From the gathered information initial topics were identified for a SEM on the martian surface. These priorities are identified and discussed below. Additionally, a concept of operations is provided with the goal of maximizing the science obtained with the minimum amount of communication with the instrument.

Microcircuit failure analysis using the SEM. [Scanning Electron Microscopes

NASA Technical Reports Server (NTRS)

Nicolas, D. P.

1974-01-01

The scanning electron microscope adds a new dimension to the knowledge that can be obtained from a failed microcircuit. When used with conventional techniques, SEM assists and clarifies the analysis, but it does not replace light microscopy. The most advantageous features for microcircuit analysis are long working distances and great depth of field. Manufacturer related failure modes of microcircuits are metallization defects, poor bonding, surface and particle contamination, and design and fabrication faults. User related failure modes are caused by abuse, such as overstress. The Physics of Failure Procedure followed by the Astrionics Laboratory in failure analysis is described, which is designed to obtain maximum information available from each step.

YieldStar based reticle 3D measurements and its application

NASA Astrophysics Data System (ADS)

Vaenkatesan, Vidya; Finders, Jo; ten Berge, Peter; Plug, Reinder; Sijben, Anko; Schellekens, Twan; Dillen, Harm; Pocobiej, Wojciech; Jorge, Vasco G.; van Dijck, Jurgen

2016-09-01

YieldStar (YS) is an established ASML-built scatterometer that is capable of measuring wafer Critical Dimension (CD), Overlay and Focus. In a recent work, the application range of YS was extended to measure 3D CD patterns on a reticle (pattern CD, height, Side Wall Angle-SWA). The primary motivation for this study came from imaging studies that indicated a need for measuring and controlling reticle 3D topography. CD scanning electron microscope (CD-SEM), Atomic force microscope (AFM), 3D multiple detector SEM (3D-SEM) are the preferred tools for reticle metrology. While these tools serve the industry well, the current research to the impact of reticle 3D involves extensive costs, logistic challenges and increased reticle lead time. YS provides an attractive alternative as it can measure pattern CD, SWA and height in a single measurement and at high throughput. This work demonstrates the capability of YS as a reticle metrology tool.

Larva of Glyptotendipes (Glyptotendipes) glaucus (Meigen 1818) (Chironomidae, Diptera)-morphology by Scanning Electron Microscope (SEM), karyotype, and biology in laboratory conditions.

PubMed

Kownacki, Andrzej; Woznicka, Olga; Szarek-Gwiazda, Ewa; Michailova, Paraskeva

2016-09-21

Larvae belonging to the family Chironomidae are difficult to identify. The aim of the present study was to describe the larval morphology of G. (G.) glaucus with the aid of a Scanning Electron Microscope (SEM), the karyotype and biology based on materials obtained from laboratory culture. Describing the morphology of larvae, special attention was paid to rarely or never described structures like the maxilla (lacinia and maxillary palp), the long plate situated below the ventromental plate, and plate X situated between lacinia and mentum. The use of SEM allowed also to obtain better images of labrum and ventromental plate. Morphological features of this species have been supplemented by karyotype and biology of larvae in laboratory conditions. Under controlled experimental conditions we found non-synchronous development of G. (G.) glaucus larvae hatched from one egg mass reflected in different lengths of larvae and emerged imagoes.

Novel perovskite coating of strontium zirconate in Inconel substrate

NASA Astrophysics Data System (ADS)

Venkatesh, G.; Blessto, B.; Rao, C. Santhosh Kumar; Subramanian, R.; Berchmans, L. John

2018-02-01

Thermal Barrier Coatings (TBC) provides a low thermal conductivity barrier to heat transfer from the hot gas in the engine to the surface of the coated alloy component. SrZrO3 powder are prepared by Sol Gel synthesis method. The synthesized powder sample is characterized by X Ray Diffraction Technique (XRD), Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM) and the results are interpreted. The Polycrystalline nature of SrZrO3 is confirmed and lattice spacing are determined in XRD. SEM shows sub-micron sized particles and a fringed pattern is observed in TEM. The IN718 specimen is Wire Cut and Sand Blasted. A SrZrO3 double layer is coated over the Inconel specimen through a Bond Coat made of NiCoCrAlY by Plasma spraying Process and also characterized. SEM analysis of the Coating shows diffusion of Fe, Sr into the substrate.

An AFM-SIMS Nano Tomography Acquisition System

NASA Astrophysics Data System (ADS)

Swinford, Richard William

An instrument, adding the capability to measure 3D volumetric chemical composition, has been constructed by me as a member of the Sanchez Nano Laboratory. The laboratory's in situ atomic force microscope (AFM) and secondary ion mass spectrometry systems (SIMS) are functional and integrated as one instrument. The SIMS utilizes a Ga focused ion beam (FIB) combined with a quadrupole mass analyzer. The AFM is comprised of a 6-axis stage, three coarse axes and three fine. The coarse stage is used for placing the AFM tip anywhere inside a (13x13x5 mm3) (xyz) volume. Thus the tip can be moved in and out of the FIB processing region with ease. The planned range for the Z-axis piezo was 60 microm, but was reduced after it was damaged from arc events. The repaired Z-axis piezo is now operated at a smaller nominal range of 18 microm (16.7 microm after pre-loading), still quite respectable for an AFM. The noise floor of the AFM is approximately 0.4 nm Rq. The voxel size for the combined instrument is targeted at 50 nm or larger. Thus 0.4 nm of xyz uncertainty is acceptable. The instrument has been used for analyzing samples using FIB beam currents of 250 pA and 5.75 nA. Coarse tip approaches can take a long time so an abbreviated technique is employed. Because of the relatively long thro of the Z piezo, the tip can be disengaged by deactivating the servo PID. Once disengaged, it can be moved laterally out of the way of the FIB-SIMS using the coarse stage. This instrument has been used to acquire volumetric data on AlTiC using AFM tip diameters of 18.9 nm and 30.6 nm. Acquisition times are very long, requiring multiple days to acquire a 50-image stack. New features to be added include auto stigmation, auto beam shift, more software automation, etc. Longer term upgrades to include a new lower voltage Z-piezo with strain-gauge feedback and a new design to extend the life for the coarse XY nano-positioners. This AFM-SIMS instrument, as constructed, has proven to be a great proof of concept vehicle. In the future it will be used to analyze micro fossils and it will also be used as a part of an intensive teaching curriculum.

Background of the FIB-4 index in Japanese non-alcoholic fatty liver disease.

PubMed

Wada, Takashi; Zeniya, Mikio

2015-01-01

We investigated the distribution and characteristics of the FIB-4 index of liver fibrosis in 1,441 Japanese men (age 50.7±10.2 years) and 304 women (age 53.9±10.3 years) who underwent comprehensive general health checkups and were identified as having non-alcoholic fatty liver disease. With respect to the FIB-4 index, differences according to sex, metabolic indices, and ultrasonic findings were investigated. Among 9,255 individuals who underwent comprehensive general health checkups, 2,750 (29.8%) were found to have mild fatty liver or fatty liver based on ultrasound findings. After excluding patients who consumed ≥150 g alcohol/week (818 individuals), those testing positive for hepatitis B surface antigens or hepatitis C virus antibody (184 individuals), and those for whom data were insufficient (three individuals), we investigated the FIB-4 indices in the remaining 1,745 subjects. There were no sex differences in the FIB-4 index. A total of 1,370 patients (78.5%) exhibited a low cut-off index (COI) (<1.30), 357 (20.5%), exhibited an indeterminate COI (1.30-2.67), and 18 (1.0%) exhibited a high COI (>2.67). There were no associations between the FIB-4 index and the constituent factors of metabolic syndrome. In contrast, there was a significant difference in the ln FIB-4 index between the patients with and without mild fatty liver or fatty liver on ultrasound among men (0.006±0.43 and -0.092±0.39, p<0.001), but not women. The FIB-4 index was is significantly lower in men, but not women, with fatty liver. The FIB-4 index must be calculated separately during medical checkups and evaluated in conjunction with ultrasound findings.

Utility of the FIB-4 Index for hepatocarcinogenesis in hepatitis C virus carriers with normal alanine aminotransferase levels.

PubMed

Ito, T; Kumada, T; Toyoda, H; Tada, T; Kiriyama, S; Tanikawa, M; Hisanaga, Y; Kanamori, A; Kitabatake, S

2015-10-01

The FIB-4 index is a simple formula using age, aspartate aminotransferase, alanine aminotransferase (ALT) and platelet count to evaluate liver fibrosis. We investigated the ability of the FIB-4 index for hepatocarcinogenesis in hepatitis C virus (HCV) carriers with normal ALT levels. A total of 516 patients with ALT levels persistently at or below 40 IU/L during an observation period of over 3 years were included. Factors associated with the development of HCC were determined. Hepatocellular carcinoma (HCC) developed in 60 of 516 patients (11.6%). The incidence rate of HCC at 5 and 10 years was 2.6% and 17.6%, respectively. When patients were categorized according to the FIB-4 index as ≤ 2.0 (n = 226), >2.0 and ≤ 4.0 (n = 169), and > 4.0 (n = 121), the cumulative incidence of HCC at 5 years was 0.5%, 1.3% and 8.0%, respectively, and 2.8%, 25.6% and 37.1% at 10 years, respectively. Patients with FIB-4 index >4.0 were at the highest risk (P < 0.001). Factors that were significantly associated with HCC in the multivariate analysis were FIB-4 index >2.0 (hazard ratio (HR), 7.690), FIB-4 index >4.0 (HR, 8.991), α-fetoprotein (AFP) >5 ng/mL (HR, 2.742), AFP >10 ng/mL (HR, 4.915) and total bilirubin >1.2 mg/dL (HR, 2.142). A scoring system for hepatocarcinogenesis that combines the FIB-4 index and AFP predicted patient outcomes with excellent discriminative ability. The FIB-4 index is strongly associated with the risk of HCC in HCV carriers with normal ALT levels. © 2015 John Wiley & Sons Ltd.

COMPARATIVE STUDY OF FIB-4 INDEX AND TRANSIENT ELASTOGRAPHY AMONG PATIENTS WITH CHRONIC HEPATITIS C VIRUS INFECTION IN GEORGIA.

PubMed

Dolmazashvili, E; Karchava, M; Abutidze, A; Sharvadze, L; Tsertsvadze, T

2017-03-01

Liver biopsy remains the reference standard for fibrosis staging. However, it has several limitations, which have led to the development of non-invasive methods. We evaluated liver fibrosis severity among HCV infected patients by comparing transient elastography (TE) and FIB-4 index. Retrospective study was conducted. Clinical data for 750 patients were obtained. The mean age of the study population was 51 years; 595 (79.3%) were male and 155 (20.7%) were female. TE and tests on biological samples were performed within one-week timeframe. Additional analyses of prothrombin index, albumin concentration, splenomegaly on abdominal ultrasound and esophageal varices on upper gastrointestinal endoscopy were performed among selected patients. Comparable results were observed among 534 patients (71.2%). FIB-4<1.45 had a negative predictive value of 89% to exclude significant fibrosis and FIB-4>3.25 had a positive predictive value of 100 % to confirm the existence of significant fibrosis. Inconclusive FIB-4 score was obtained in 170 (22.7%) patients. Of them 127 (74.7%) had significant fibrosis (F3-F4) by TE. Discordant results (FIB-4 <1.45 and Liver Stiffness Measurement (LSM) >9.5 kpa) were observed in 46 (6.1%) of patients. Low prothrombin index, low albumin concentration, splenomegaly and esophageal varices were significantly (p<0.001) correlated with TE results. Discrepancy showing high FIB-4 score and low LSM was not observed in our cohort. There was a good correlation between TE and FIB-4 score. FIB-4 could rapidly replace expensive methods to assess liver fibrosis severity in some scenarios. However, our study demonstrated superiority of TE. LSM correlated better with indirect markers of significant fibrosis.

ATLAS of Microorganisms from Ancient Phosphorites of Khubsugul (Mongolia)

NASA Technical Reports Server (NTRS)

Zhengallo, Elena A.; Rozanov, Alexei Yu.; Ushatinskaya, Galina T.; Hoover, Richard B.; Gerasimenko, Ludmila M.; Ragozina, Alla L.

2000-01-01

A photographic atlas of scanning electron microscope (SEM) images of Cambrian (Tommotian) microfossils from the phosphorites of Khubsugul Mongolia is presented. SEM images of modern cyanobacteria and bacteria are provided for comparison. The importance of bacterial fossils and morphological biomarkers to astrobiology and the understanding of the origin of phosphorites is considered.

Helium ion microscopy and energy selective scanning electron microscopy - two advanced microscopy techniques with complementary applications

NASA Astrophysics Data System (ADS)

Rodenburg, C.; Jepson, M. A. E.; Boden, Stuart A.; Bagnall, Darren M.

2014-06-01

Both scanning electron microscopes (SEM) and helium ion microscopes (HeIM) are based on the same principle of a charged particle beam scanning across the surface and generating secondary electrons (SEs) to form images. However, there is a pronounced difference in the energy spectra of the emitted secondary electrons emitted as result of electron or helium ion impact. We have previously presented evidence that this also translates to differences in the information depth through the analysis of dopant contrast in doped silicon structures in both SEM and HeIM. Here, it is now shown how secondary electron emission spectra (SES) and their relation to depth of origin of SE can be experimentally exploited through the use of energy filtering (EF) in low voltage SEM (LV-SEM) to access bulk information from surfaces covered by damage or contamination layers. From the current understanding of the SES in HeIM it is not expected that EF will be as effective in HeIM but an alternative that can be used for some materials to access bulk information is presented.

Effects of Antiadhesion preparation on free fibrinogen and fibrin degrading products in abdominal exudates of rabbits postoperatively

PubMed Central

Wang, You-Li; Pan, Cheng-En; Yang, Ping-Lin; Tian, Yuan; Pei, Shu-Wen; Dong, Ming

2004-01-01

AIM: To observe effects of ACOL on fibrinogen (FIB), fibrin degrading products (FDP) and changes of FIB and FDP concentration in rabbits with intro-abdominal exudates during 7 d after major abdominal surgery. METHODS: Sixty New Zealand rabbits were randomly divided into 4 groups: ACOL group, the control group, DCT group and the normal group. After being modeled, except the normal group, the other 3 groups were treated with different ways for a week; the intro-abdominal exudates of rabbits in the 4 groups were drawn for FIB and FDP measurement once daily during 7 d after major abdominal surgery. RESULTS: FIB and FDP in the intro-abdominal exudates altered in a regular way and ACOL could change the concentration of FIB and FDP in the intra-abdominal exudates after major abdominal surgery. CONCLUSION: ACOL can prevent intestinal adhesion by reducing the concentration of FIB and raising that of FDP in the intro-abdominal exudates after major abdominal surgery. PMID:15309738

Scanning electron microscopy of clays and clay minerals

USGS Publications Warehouse

Bohor, B.F.; Hughes, R.E.

1971-01-01

The scanning electron microscope (SEM) proves to be ideally suited for studying the configuration, texture, and fabric of clay samples. Growth mechanics of crystalline units—interpenetration and interlocking of crystallites, crystal habits, twinning, helical growth, and topotaxis—also are uniquely revealed by the SEM.Authigenic kaolins make up the bulk of the examples because their larger crystallite size, better crystallinity, and open texture make them more suited to examination by the SEM than most other clay mineral types.

Fractal evaluation of drug amorphicity from optical and scanning electron microscope images

NASA Astrophysics Data System (ADS)

Gavriloaia, Bogdan-Mihai G.; Vizireanu, Radu C.; Neamtu, Catalin I.; Gavriloaia, Gheorghe V.

2013-09-01

Amorphous materials are metastable, more reactive than the crystalline ones, and have to be evaluated before pharmaceutical compound formulation. Amorphicity is interpreted as a spatial chaos, and patterns of molecular aggregates of dexamethasone, D, were investigated in this paper by using fractal dimension, FD. Images having three magnifications of D were taken from an optical microscope, OM, and with eight magnifications, from a scanning electron microscope, SEM, were analyzed. The average FD for pattern irregularities of OM images was 1.538, and about 1.692 for SEM images. The FDs of the two kinds of images are less sensitive of threshold level. 3D images were shown to illustrate dependence of FD of threshold and magnification level. As a result, optical image of single scale is enough to characterize the drug amorphicity. As a result, the OM image at a single scale is enough to characterize the amorphicity of D.

Nanomanipulation and nanofabrication with multi-probe scanning tunneling microscope: from individual atoms to nanowires.

PubMed

Qin, Shengyong; Kim, Tae-Hwan; Wang, Zhouhang; Li, An-Ping

2012-06-01

The wide variety of nanoscale structures and devices demands novel tools for handling, assembly, and fabrication at nanoscopic positioning precision. The manipulation tools should allow for in situ characterization and testing of fundamental building blocks, such as nanotubes and nanowires, as they are built into functional devices. In this paper, a bottom-up technique for nanomanipulation and nanofabrication is reported by using a 4-probe scanning tunneling microscope (STM) combined with a scanning electron microscope (SEM). The applications of this technique are demonstrated in a variety of nanosystems, from manipulating individual atoms to bending, cutting, breaking carbon nanofibers, and constructing nanodevices for electrical characterizations. The combination of the wide field of view of SEM, the atomic position resolution of STM, and the flexibility of multiple scanning probes is expected to be a valuable tool for rapid prototyping in the nanoscience and nanotechnology.

Scanning and transmission electron microscopic observation of the parasitic form of Trichophyton violaceum in the infected hair from tinea capitis.

PubMed

Zhuang, Kaiwen; Ran, Xin; Lei, Song; Zhang, Chaoliang; Lama, Jebina; Ran, Yuping

2014-01-01

Trichophyton violaceum is a pathogen of tinea capitis and usually cause infection of scalp and hair in children. To investigate the parasitic form of T. violaceum in the human hair tissue, the infected hair strands were collected from a 9-year-old boy with tinea capitis due to T. violaceum and observed under both the scanning electron microscope (SEM) and transmission electron microscope (TEM). The SEM and TEM findings revealed that T. violaceum parasitically lives in the hair shaft in various forms and the morphological transformation of the fungus from hyphae into arthrospores was noted. The involved hair shaft was damaged to the great extent and its ultrastructural changes were evident. Those morphological characteristics of T. violaceum and the three-dimensional ultastructure changes of infected hairs give a better knowledge about the host-fungus relationship in tinea capitis. © 2014 Wiley Periodicals, Inc.

The FIB-4 index is a significant prognostic factor in patients with non-B non-C hepatocellular carcinoma after curative surgery.

PubMed

Okamura, Yukiyasu; Ashida, Ryo; Yamamoto, Yusuke; Ito, Takaaki; Sugiura, Teiichi; Bekku, Emima; Aramaki, Takeshi; Uesaka, Katsuhiko

2016-03-01

The aspartate aminotransferase to platelet ratio index (APRI) and fibrosis-4 (FIB-4) index were developed as a non-invasive parameter for predicting liver fibrosis. This study aimed to validate the APRI and FIB-4 indexes in patients treated with curative therapy for non-B non-C (NBNC) hepatocellular carcinoma (HCC). Accumulated database comprising 399 patients who underwent hepatectomy was reviewed retrospectively. Analyses were performed to evaluate whether the APRI and FIB-4 indexes are predictors of liver cirrhosis and/or the prognosis in patients with NBNC-HCC. Forty-seven patients with NBNC-HCC who underwent curative radiofrequency ablation therapy (RFA) in the same period were enrolled as the validation set. The APRI and FIB-4 indexes were significantly higher in the cirrhosis group than in the no-cirrhosis group (P = 0.001 and P < 0.001, respectively). A receiver operating characteristic curve analysis showed that the FIB-4 index was more accurate in predicting background liver cirrhosis than the APRI. According to a multivariate analysis, an FIB-4 index larger than 2.7 (hazard ratio 2.11 and 2.21, 95 % confidence interval 1.06-4.18 and 1.38-3.54, P = 0.033 and P = 0.001) remained significant independent predictors of overall and recurrence-free survival, respectively. The present findings showed that the FIB-4 index is a significant predictor of background liver cirrhosis and the prognosis after curative resection for NBNB-HCC.

Diagnosis of cervical cancer cell taken from scanning electron and atomic force microscope images of the same patients using discrete wavelet entropy energy and Jensen Shannon, Hellinger, Triangle Measure classifier.

PubMed

Aytac Korkmaz, Sevcan

2016-05-05

The aim of this article is to provide early detection of cervical cancer by using both Atomic Force Microscope (AFM) and Scanning Electron Microscope (SEM) images of same patient. When the studies in the literature are examined, it is seen that the AFM and SEM images of the same patient are not used together for early diagnosis of cervical cancer. AFM and SEM images can be limited when using only one of them for the early detection of cervical cancer. Therefore, multi-modality solutions which give more accuracy results than single solutions have been realized in this paper. Optimum feature space has been obtained by Discrete Wavelet Entropy Energy (DWEE) applying to the 3×180 AFM and SEM images. Then, optimum features of these images are classified with Jensen Shannon, Hellinger, and Triangle Measure (JHT) Classifier for early diagnosis of cervical cancer. However, between classifiers which are Jensen Shannon, Hellinger, and triangle distance have been validated the measures via relationships. Afterwards, accuracy diagnosis of normal, benign, and malign cervical cancer cell was found by combining mean success rates of Jensen Shannon, Hellinger, and Triangle Measure which are connected with each other. Averages of accuracy diagnosis for AFM and SEM images by averaging the results obtained from these 3 classifiers are found as 98.29% and 97.10%, respectively. It has been observed that AFM images for early diagnosis of cervical cancer have higher performance than SEM images. Also in this article, surface roughness of malign AFM images in the result of the analysis made for the AFM images, according to the normal and benign AFM images is observed as larger, If the volume of particles has found as smaller. Copyright © 2016 Elsevier B.V. All rights reserved.

Signal-to-noise ratio estimation on SEM images using cubic spline interpolation with Savitzky-Golay smoothing.

PubMed

Sim, K S; Kiani, M A; Nia, M E; Tso, C P

2014-01-01

A new technique based on cubic spline interpolation with Savitzky-Golay noise reduction filtering is designed to estimate signal-to-noise ratio of scanning electron microscopy (SEM) images. This approach is found to present better result when compared with two existing techniques: nearest neighbourhood and first-order interpolation. When applied to evaluate the quality of SEM images, noise can be eliminated efficiently with optimal choice of scan rate from real-time SEM images, without generating corruption or increasing scanning time. © 2013 The Authors Journal of Microscopy © 2013 Royal Microscopical Society.

A Simulation of the Topographic Contrast in the SEM

NASA Astrophysics Data System (ADS)

Kotera, Masatoshi; Fujiwara, Takafumi; Suga, Hiroshi; Wittry, David B.

1990-10-01

A simulation model is presented to analyze the topographic contast in the scanning electron microscope (SEM). This simulation takes into account all major mechanisms from signal generation to signal detection in the SEM. The calculated result shows that the resolution of the secondary electron image is better than that of the backscattered electron image for 1 and 3 keV primary electrons incident on an Al target. An asymmetric intensity profile of a signal at a topographic pattern, usually found in the SEM equipped with the Everhart-Thornley detector, is mainly due to the asymmetric profile of the backscattered electron signal.

Epitaxial graphene growth on FIB patterned 3C-SiC nanostructures on Si (111): reducing milling damage.

PubMed

Amjadipour, Mojtaba; MacLeod, Jennifer; Lipton-Duffin, Josh; Iacopi, Francesca; Motta, Nunzio

2017-08-25

Epitaxial growth of graphene on SiC is a scalable procedure that does not require any further transfer step, making this an ideal platform for graphene nanostructure fabrication. Focused ion beam (FIB) is a very promising tool for exploring the reduction of the lateral dimension of graphene on SiC to the nanometre scale. However, exposure of graphene to the Ga + beam causes significant surface damage through amorphisation and contamination, preventing epitaxial graphene growth. In this paper we demonstrate that combining a protective silicon layer with FIB patterning implemented prior to graphene growth can significantly reduce the damage associated with FIB milling. Using this approach, we successfully achieved graphene growth over 3C-SiC/Si FIB patterned nanostructures.

Studies on rock characteristics and timing of creep at selected landslide sites in Taiwan

Treesearch

Cheng-Yi Lee

2000-01-01

A study was conducted to investigate the causes of and rock characteristics at three landslide sites in the Tesngwen Reservoir watershed of southern Taiwan. Research methods used included the petrographic microscope, X-ray diffraction (XRD), scanning electron microscope (SEM), inductively coupled plasma spectroscope (ICP), constant head permeameter in triaxial...

Solar-cell defect analyzer

NASA Technical Reports Server (NTRS)

Gauthier, M. K.; Miller, E. L.; Shumka, A.

1980-01-01

Laser-Scanning System pinpoints imperfections in solar cells. Entire solar panels containing large numbers of cells can be scanned. Although technique is similar to use of scanning electron microscope (SEM) to locate microscopic imperfections, it differs in that large areas may be examined, including entire solar panels, and it is not necessary to remove cover glass or encapsulants.

Arc-melting preparation of single crystal LaB.sub.6 cathodes

DOEpatents

Gibson, Edwin D.; Verhoeven, John D.

1977-06-21

A method for preparing single crystals of lanthanum hexaboride (LaB.sub.6) by arc melting a rod of compacted LaB.sub.6 powder. The method is especially suitable for preparing single crystal LaB.sub.6 cathodes for use in scanning electron microscopes (SEM) and scanning transmission electron microscopes (STEM).

Melting relations in the MgO-MgSiO3 system up to 70 GPa

NASA Astrophysics Data System (ADS)

Ohnishi, Satoka; Kuwayama, Yasuhiro; Inoue, Toru

2017-06-01

Melting experiments in a binary system MgO-MgSiO3 were performed up to 70 GPa using a CO2 laser heated diamond anvil cell. The quenched samples were polished and analyzed by a dualbeam focused ion beam (FIB) and a field emission scanning electron microscope (FE-SEM), respectively. The liquidus phase and the eutectic composition were determined on the basis of textual and chemical analyses of sample cross sections. Our experimental results show that the eutectic composition is the Si/Mg molar ratio of 0.76 at 35 GPa and it decreases with increasing pressure. Above 45 GPa, it becomes relatively constant at about 0.64-0.65 Si/Mg molar ratio. Using our experimental data collected at a wide pressure range up to 70 GPa together with previous experimental data, we have constructed a thermodynamic model of the eutectic composition of the MgO-MgSiO3 system. The eutectic composition extrapolated to the pressure and temperature conditions at the base of the mantle is about 0.64 Si/Mg molar ratio. The modeled eutectic composition is quite consistent with a previous prediction from ab initio calculations (de Koker et al. in Earth Planet Sci Lett 361:58-63, 2013), suggesting that the simple assumption of a non-ideal regular solution model can well describe the melting relation of the MgO-MgSiO3 system at high pressure. Our results show that the liquidus phase changes from MgO-periclase to MgSiO3-bridgmanite at 35 GPa for the simplified pyrolite composition ( 0.7 Si/Mg molar ratio), while MgSiO3-bridgmanite is the liquidus phase at the entire lower mantle conditions for the chondritic composition ( 0.84 Si/Mg molar ratio).

Moissanite (SiC) with metal-silicide and silicon inclusions from tuff of Israel: Raman spectroscopy and electron microscope studies

NASA Astrophysics Data System (ADS)

Dobrzhinetskaya, Larissa; Mukhin, Pavel; Wang, Qin; Wirth, Richard; O'Bannon, Earl; Zhao, Wenxia; Eppelbaum, Lev; Sokhonchuk, Tatiana

2018-06-01

Here, we present studies of natural SiC that occurs in situ in tuff related to the Miocene alkaline basalt formation deposited in northern part of Israel. Raman spectroscopy, SEM and FIB-assisted TEM studies revealed that SiC is primarily hexagonal polytypes 4H-SiC and 6H-SiC, and that the 4H-SiC polytype is the predominant phase. Both SiC polytypes contain crystalline inclusions of silicon (Sio) and inclusions of metal-silicide with varying compositions (e.g. Si58V25Ti12Cr3Fe2, Si41Fe24Ti20Ni7V5Zr3, and Si43Fe40Ni17). The silicides crystal structure parameters match Si2TiV5 (Pm-3m space group, cubic), FeSi2Ti (Pbam space group, orthorhombic), and FeSi2 (Cmca space group, orthorhombic) respectively. We hypothesize that SiC was formed in a local ultra-reduced environment at respectively shallow depths (60-100 km), through a reaction of SiO2 with highly reducing fluids (H2O-CH4-H2-C2H6) arisen from the mantle "hot spot" and passing through alkaline basalt magma reservoir. SiO2 interacting with the fluids may originate from the walls of the crustal rocks surrounding this magmatic reservoir. This process led to the formation of SiC and accompanied by the reducing of metal-oxides to native metals, alloys, and silicides. The latter were trapped by SiC during its growth. Hence, interplate "hot spot" alkali basalt volcanism can now be included as a geological environment where SiC, silicon, and silicides can be found.

Depth-section imaging of swine kidney by spectrally encoded microscopy

NASA Astrophysics Data System (ADS)

Liao, Jiuling; Gao, Wanrong

2016-10-01

The kidneys are essential regulatory organs whose main function is to regulate the balance of electrolytes in the blood, along with maintaining pH homeostasis. The study of the microscopic structure of the kidney will help identify kidney diseases associated with specific renal histology change. Spectrally encoded microscopy (SEM) is a new reflectance microscopic imaging technique in which a grating is used to illuminate different positions along a line on the sample with different wavelengths, reducing the size of system and imaging time. In this paper, a SEM device is described which is based on a super luminescent diode source and a home-built spectrometer. The lateral resolution was measured by imaging the USAF resolution target. The axial response curve was obtained as a reflect mirror was scanned through the focal plane axially. In order to test the feasibility of using SEM for depth-section imaging of an excised swine kidney tissue, the images of the samples were acquired by scanning the sample at 10 μm per step along the depth direction. Architectural features of the kidney tissue could be clearly visualized in the SEM images, including glomeruli and blood vessels. Results from this study suggest that SEM may be useful for locating regions with probabilities of kidney disease or cancer.

Miniature Variable Pressure Scanning Electron Microscope for In-Situ Imaging and Chemical Analysis

NASA Technical Reports Server (NTRS)

Gaskin, Jessica A.; Jerman, Gregory; Gregory, Don; Sampson, Allen R.

2012-01-01

NASA Marshall Space Flight Center (MSFC) is leading an effort to develop a Miniaturized Variable Pressure Scanning Electron Microscope (MVP-SEM) for in-situ imaging and chemical analysis of uncoated samples. This instrument development will be geared towards operation on Mars and builds on a previous MSFC design of a mini-SEM for the moon (funded through the NASA Planetary Instrument Definition and Development Program). Because Mars has a dramatically different environment than the moon, modifications to the MSFC lunar mini-SEM are necessary. Mainly, the higher atmospheric pressure calls for the use of an electron gun that can operate at High Vacuum, rather than Ultra-High Vacuum. The presence of a CO2-rich atmosphere also allows for the incorporation of a variable pressure system that enables the in-situ analysis of nonconductive geological specimens. Preliminary testing of Mars meteorites in a commercial Environmental SEM(Tradmark) (FEI) confirms the usefulness of lowcurrent/low-accelerating voltage imaging and highlights the advantages of using the Mars atmosphere for environmental imaging. The unique capabilities of the MVP-SEM make it an ideal tool for pursuing key scientific goals of NASA's Flagship Mission Max-C; to perform in-situ science and collect and cache samples in preparation for sample return from Mars.

A simple cryo-holder facilitates specimen observation under a conventional scanning electron microscope.

PubMed

Tang, Chih-Yuan; Huang, Rong-Nan; Kuo-Huang, Ling-Long; Kuo, Tai-Chih; Yang, Ya-Yun; Lin, Ching-Yeh; Jane, Wann-Neng; Chen, Shiang-Jiuun

2012-02-01

A pre-cryogenic holder (cryo-holder) facilitating cryo-specimen observation under a conventional scanning electron microscope (SEM) is described. This cryo-holder includes a specimen-holding unit (the stub) and a cryogenic energy-storing unit (a composite of three cylinders assembled with a screw). After cooling, the cryo-holder can continue supplying cryogenic energy to extend the observation time for the specimen in a conventional SEM. Moreover, the cryogenic energy-storing unit could retain appropriate liquid nitrogen that can evaporate to prevent frost deposition on the surface of the specimen. This device is proved feasible for various tissues and cells, and can be applied to the fields of both biology and material science. We have employed this novel cryo-holder for observation of yeast cells, trichome, and epidermal cells in the leaf of Arabidopsis thaliana, compound eyes of insects, red blood cells, filiform papillae on the surface of rat tongue, agar medium, water molecules, penicillium, etc. All results suggested that the newly designed cryo-holder is applicable for cryo-specimen observation under a conventional SEM without cooling system. Most importantly, the design of this cryo-holder is simple and easy to operate and could adapt a conventional SEM to a plain type cryo-SEM affordable for most laboratories. Copyright © 2011 Wiley Periodicals, Inc.

Ultrastructural changes in tracheal epithelial cells exposed to oxygen

NASA Technical Reports Server (NTRS)

Philpott, D. E.; Harrison, G. A.; Turnbill, C.; Black, S.

1977-01-01

White albino rats were sacrificed after 24, 36, 48, 72, and 96 h of exposure to 100% O2 at 1 atm. Tissue was prepared for the scanning electron microscope (SEM) by Critical Point Drying and for the transmission electron microscope (TEM) by plastic embedding. Scanning microscopy showed a loss of microvilli after 48 h of exposure. Cilia appeared relatively normal with SEM, but TEM revealed changes in the outer membrane. In TEM, nonciliated cells appeared swollen and often encroached on the ciliated cells. A heavy mucous blanket remained even after processing. All the changes observed that are induced by oxygen exposure contribute to mucostasis, reducing and/or halting mucociliary clearance.

Fibrinogen, Riboflavin, and UVA to Immobilize a Corneal Flap—Conditions for Tissue Adhesion

PubMed Central

Littlechild, Stacy L.; Brummer, Gage; Zhang, Yuntao; Conrad, Gary W.

2012-01-01

Purpose. Laser-assisted in situ keratomileus (LASIK) creates a permanent flap that remains non-attached to the underlying laser-modified stroma. This lack of permanent adhesion is a liability. To immobilize a corneal flap, a protocol using fibrinogen (FIB), riboflavin (RF), and ultraviolet (UVA) light (FIB+RF+UVA) was devised to re-adhere the flap to the stroma. Methods. A model flap was created using rabbit (Oryctolagus cuniculus) and shark (Squalus acanthias) corneas. Solutions containing FIB and RF were applied between corneal strips as glue. Experimental corneas were irradiated with long wavelength (365 nm) UVA. To quantify adhesive strength between corneal strips, the glue-tissue interface was subjected to a constant force while a digital force gauge recorded peak tension. Results. In the presence of FIB, substantive non-covalent interactions occurred between rabbit corneal strips. Adhesiveness was augmented if RF and UVA also were applied, suggesting formation of covalent bonds. Additionally, exposing both sides of rabbit corneas to UVA generated more adhesion than exposure from one side, suggesting that RF in the FIB solution catalyzes formation of covalent bonds at only the interface between stromal molecules and FIB closest to the UVA. In contrast, in the presence of FIB, shark corneal strips interacted non-covalently more substantively than those of rabbits, and adhesion was not augmented by applying RF+UVA, from either or both sides. Residual RF could be rinsed away within 1 hour. Conclusions. Glue solution containing FIB and RF, together with UVA treatment, may aid immobilization of a corneal flap, potentially reducing risk of flap dislodgement. PMID:22589434

Preparation and characterization of biohybrid poly (3-hydroxybutyrate-co-3-hydroxyvalerate) based nanofibrous scaffolds

NASA Astrophysics Data System (ADS)

Kouhi, Monireh; Fathi, Mohammadhossein; Venugopal, Jayarama Reddy; Shamanian, Morteza; Ramakrishna, Seeram

2018-01-01

Development of bioengineered scaffolds for bone tissue regeneration is a growing area of research, especially those involving biodegradable electrospun nanofibers incorporated with ceramic nanoparticles, since they can mimic the extracellular matrix (ECM) of the native bone. In the current study, a biocomposite nanofibrous scaffolds consisting of poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), fibrinogen (FIB) and bredigite (BR) nanoparticles was fabricated through electrospinning. The morphological, chemical and mechanical characteristics of the resultant scaffolds were studied by using field emission-scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FTIR) and tensile tester, respectively. It was found that PHBV-FIB-BR scaffolds exhibited enhanced tensile strength and young modulus compared to PHBV and PHBV-FIB scaffolds. In addition, the measurements of the water contact angle suggested that incorporation of bredigite and fibrinogen into PHBV could improve the hydrophilicity of the composites. The results of bioactivity assessment performed in the simulated body fluid (SBF) demonstrated that the presence of the bredigite nanoparticles induced the nucleation and growth of apatite layer on the surface of PHBV-FIB-BR scaffold in SBF. Furthermore, the ion concentration changes of SBF solutions with composite scaffolds showed that PHBV-FIB-BR scaffolds released Ca and Si ions, which can stimulate osteoblast proliferation. The results of cell culture studies revealed the higher osteoblast proliferation, mineralization and differentiation on PHBV-FIB-BR and PHBV-FIB scaffolds than on PHBV. Our results suggest that PHBV-FIB-BR nanofibrous scaffold would be a promising candidate as a biocomposite nanofibrous scaffold material for tissue engineering applications.

Validation of APRI and FIB-4 score in an Antwerp cohort of chronic hepatitis C patients.

PubMed

Verlinden, Wim; Bourgeois, Stefan; De Maeyer, Marc; Vonghia, Luisa; Vanwolleghem, Thomas; Michielsen, Peter; Francque, Sven

2015-12-01

Evaluation of liver fibrosis in chronic hepatitis C patients guides clinical decision-making. The aim of this study is to validate APRI and FIB-4, two easily calculated noninvasive tests to predict fibrosis, in chronic HCV patients using biopsy as a gold standard and to compare accuracy between HCV monoinfected and HIV/HCV coinfected patients. We retrospectively studied HCV patients of two centres who underwent liver biopsy. Liver fibrosis was staged according to METAVIR. 136 patients were included. The AUROC of FIB-4 (0.896) to discriminate F0-F2 vs. F3-F4 was significantly higher (p=0.0186) than the AUROC of APRI (0.842). The difference in AUROC between HIV-negative and positive patients was not significant for APRI (p=0.471), nor for FIB-4 (p=0.495). Performance status was lower in HIV-positive patients with 46.7% and 69.0% of patients correctly classified using APRI and FIB-4, compared to 56.6% and 73.6% in HIV-negative patients, respectively. Conversion of transaminase values from one hospital to the other did not significantly change the AUROC of FIB-4 (p=0.928). APRI and FIB-4 have a better performance status in HCV monoinfected patients compared to HIV/HCV coinfected patients. FIB-4 has a better AUROC compared to APRI and is the preferred noninvasive fibrosis score to discriminate between F0-F2 and F3-F4. Different hospitals should use their local absolute serum transaminase values without conversion. © Acta Gastro-Enterologica Belgica.

Characterization of nutrients and fecal indicator bacteria at a concentrated swine feeding operation in Wake County, North Carolina, 2009-2011

USGS Publications Warehouse

Harden, Stephen L.; Rogers, Shane W.; Jahne, Michael A.; Shaffer, Carrie E.; Smith, Douglas G.

2012-01-01

Study sites were sampled for laboratory analysis of nutrients, total suspended solids (TSS), and (or) fecal indicator bacteria (FIB). Nutrient analyses included measurement of dissolved ammonia, total and dissolved ammonia + organic nitrogen, dissolved nitrate + nitrite, dissolved orthophosphate, and total phosphorus. The FIB analyses included measurement of Escherichia coli and enterococci. Samples of wastewater at the swine facility were collected from a pipe outfall from the swine housing units, two storage lagoons, and the spray fields for analysis of nutrients, TSS, and FIB. Soil samples collected from a spray field were analyzed for FIB. Monitoring locations were established for collecting discharge and water-quality data during storm events at three in-field runoff sites and two sites on the headwater stream (one upstream and one downstream) next to the swine facility. Stormflow samples at the five monitoring locations were collected for four storm events during 2009 to 2010 and analyzed for nutrients, TSS, and FIB. Monthly water samples also were collected during base-flow conditions at all four stream sites for laboratory analysis of nutrients, TSS, and (or) FIB.

Detection of Helicobacter pylori and fecal indicator bacteria in five North American rivers.

USGS Publications Warehouse

Voytek, M.A.; Ashen, J.B.; Fogarty, L.R.; Kirshtein, J.D.; Landa, E.R.

2005-01-01

This study examines the use of fecal indicator bacteria (FIB) as a predictor of the presence of Helicobacter spp. A combination of standard culture and molecular techniques were used to detect and quantify FIB, Helicobacter spp. and H. pylori from five North American rivers of different size and with different land use characteristics. Primers designed to amplify genes specific to Helicobacter spp. and H. pylori were evaluated for their efficacy in detection and quantification in environmental samples. Helicobacter spp. were detected in 18/33 (55%) of river samples. H. pylori was detected in 11/33 (33%) of river samples. FIB were found in 32/33 (96%) of river samples. When FIB abundance exceeded USEPA water quality standards for single samples, Helicobacter or H. pylori were detected in 7/15 (47%) cases. No numerical correlation was found between the presence of FIB and either Helicobacter spp. or H. pylori. This suggests that the presence of FIB will be of limited use for detection of Helicobacter spp. or H. pylori by public health agencies.

Three-dimensional patterning in polymer optical waveguides using focused ion beam milling

NASA Astrophysics Data System (ADS)

Kruse, Kevin; Burrell, Derek; Middlebrook, Christopher

2016-07-01

Waveguide (WG) photonic-bridge taper modules are designed for symmetric planar coupling between silicon WGs and single-mode fibers (SMFs) to minimize photonic chip and packaging footprint requirements with improving broadband functionality. Micromachined fabrication and evaluation of polymer WG tapers utilizing high-resolution focused ion beam (FIB) milling is performed and presented. Polymer etch rates utilizing the FIB and optimal methods for milling polymer tapers are identified for three-dimensional patterning. Polymer WG tapers with low sidewall roughness are manufactured utilizing FIB milling and optically tested for fabrication loss. FIB platforms utilize a focused beam of ions (Ga+) to etch submicron patterns into substrates. Fabricating low-loss polymer WG taper prototypes with the FIB before moving on to mass-production techniques provides theoretical understanding of the polymer taper and its feasibility for connectorization devices between silicon WGs and SMFs.

A drug-like antagonist inhibits thyrotropin receptor-mediated stimulation of cAMP production in Graves' orbital fibroblasts.

PubMed

Neumann, Susanne; Pope, Arthur; Geras-Raaka, Elizabeth; Raaka, Bruce M; Bahn, Rebecca S; Gershengorn, Marvin C

2012-08-01

Fibroblasts (FIBs) within the retro-orbital space of patients with Graves' disease (GOFs) express thyrotropin receptors (TSHRs) and are thought to be an orbital target of TSHR-stimulating autoantibodies in Graves' ophthalmopathy (GO). Recently, we developed a low molecular weight, drug-like TSHR antagonist (NCGC00229600) that inhibited TSHR activation in a model cell system overexpressing TSHRs and in normal human thyrocytes expressing endogenous TSHRs. Herein, we test the hypothesis that NCGC00229600 will inhibit activation of TSHRs endogenously expressed in GOFs. Three strains of GOFs, previously obtained from patients with GO, were studied as undifferentiated FIBs and after differentiation into adipocytes (ADIPs), and another seven strains were studied only as FIBs. ADIP differentiation was monitored by morphology and measurement of adiponectin mRNA. FIBs and ADIPs were treated with the TSH- or TSHR-stimulating antibody M22 in the absence or presence of NCGC00229600 and TSHR activation was monitored by cAMP production. FIBs contained few if any lipid vesicles and undetectable levels of adiponectin mRNA, whereas ADIPs exhibited abundant lipid vesicles and levels of adiponectin mRNA more than 250,000 times greater than FIBs; TSHR mRNA levels were 10-fold higher in ADIPs than FIBs. FIBs exhibited higher absolute levels of basal and forskolin-stimulated cAMP production than ADIPs. Consistent with previous findings, TSH stimulated cAMP production in the majority of ADIP strains and less consistently in FIBs. Most importantly, NCGC00229600 reduced both TSH- and M22-stimulated cAMP production in GOFs. These data confirm previous findings that TSHR activation may cause increased cAMP production in GOFs and show that NCGC00229600 can inhibit TSHR activation in GOFs. These findings suggest that drug-like TSHR antagonists may have a role in treatment of GO.

Validation of the FIB-4 index for evaluation of fibrosis in patients with recurrent hepatitis C after living donor liver transplantation: A single center experience.

PubMed

Kitajima, Toshihiro; Kaido, Toshimi; Hamaguchi, Yuhei; Yagi, Shintaro; Taura, Kojiro; Fujimoto, Yasuhiro; Hatano, Etsuro; Okajima, Hideaki; Haga, Hironori; Uemoto, Shinji

2016-07-01

The FIB-4 index has been proposed as a simple, non-invasive surrogate marker of liver fibrosis in patients with hepatitis C virus (HCV). However, the utility of FIB-4 in HCV positive patients after living donor liver transplantation (LDLT) has not been assessed. The aim of this study was to evaluate the efficacy of FIB-4 in the detection of significant liver graft fibrosis caused by recurrent HCV infection after LDLT compared with other simple fibrosis markers. A total of 259 liver biopsies (LB) with evidence of recurrent HCV were taken from 110 HCV positive LDLT patients who had undergone concomitant splenectomy before administration of antiviral therapy. In LB performed at 3 months or later after LT (n = 202, subject group), FIB-4 was compared between fibrosis stages and the accuracy of FIB-4 in predicting significant fibrosis (METAVIR, F ≥ 2) was assessed compared with aspartate aminotransferase (AST) to alanine aminotransferase (ALT) ratio, age-platelet index, and AST to platelet ratio index (APRI). FIB-4 was significantly different between all fibrosis stages (F0 and F1-F4, P = 0.022; F0/1 and F2-F4, P < 0.0005; and F0-F2 and F3F4, P = 0.034) and provided the best area under the receiver-operator curve (AUROC) compared with other markers (FIB-4, 0.711; APRI, 0.693; age-platelet index, 0.663; and AST to ALT ratio, 0.562). The optimal cut-off value to identify significant fibrosis was 2.20 with 65% sensitivity and 69% specificity. FIB-4 is a more reliable marker for diagnosing significant liver fibrosis than APRI, age-platelet index, and AST to ALT ratio in LDLT patients with HCV. © 2015 The Japan Society of Hepatology.

Comparing the efficiency of Fib-4, Egy-score, APRI, and GUCI in liver fibrosis staging in Egyptians with chronic hepatitis C.

PubMed

Cordie, Ahmed; Salama, Ahmed; El-Sharkawy, Marwa; El-Nahaas, Saeed M; Khairy, Marwa; Elsharkawy, Aisha; Hassany, Mohamed; Esmat, Gamal

2018-06-01

Assessment of hepatic fibrosis in chronic hepatitis C virus patients by liver biopsy is not widely accepted despite its accuracy, being invasive, carrying complications, and adding cost. This paved the way to development and use of non-invasive markers of fibrosis in diagnosis of hepatic fibrosis. We aimed at evaluating the efficiency of Fib-4, Egy-score, Aspartate-to-platelet ratio index (APRI), and Göteborg University Cirrhosis Index (GUCI) in comparison to liver biopsy, in the assessment of hepatic fibrosis in chronic hepatitis C patients. This was a cross sectional study including 200 chronic HCV patients were divided into two groups according to stage of fibrosis (Metavir score) into non-significant fibrosis (1.27, APRI >0.48, Egy-score >0.73, and GUCI >0.57 significantly predict significant fibrosis (P < 0.01). Fib-4 carries the best performance and significant reliability with AUROC 0.783, sensitivity 74%, specificity 69%, PPV 0.55, and NPV 0.86. The addition of BMI to Fib-4 improved the significant fibrosis AUROC curve performance but did not reach statistical significant improvement. We concluded that age and BMI are good predictors of hepatic fibrosis. Fib-4 (>1.27) is the best method of prediction of significant fibrosis compared to Egy-score, APRI, and GUCI. Addition of BMI to Fib-4 did not improve diagnostic value of Fib-4. © 2018 Wiley Periodicals, Inc.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kantor, M. M., E-mail: Kantor@imet.ac.ru; Vorkachev, K. G., E-mail: KGV@imet.ac.ru

The efficiency of different techniques application for the investigation of orientation inhomogeneities in polycrystalline materials was studied using FEG SEM-FIB dual beam station equipped with EBSD. It is shown that for the visualization of pearlitic ferrite fragments it is more appropriate to acquire the images in secondary electrons induced by Ga ions. At the same time for the visualization of nano-sized particles it is more prospective to use images in forward scatter electrons in combination with IQ maps. It is established that pearlitic ferrite fragments are not flat. Complicated spatial configuration of orientation inhomogeneities in pearlitic ferrite is shown bymore » means of 3-d reconstruction. The features of ferrites aggregation are revealed depending on pearlitic ferrite fragmentation criterion. The existence of long-range misorientations in the aggregation area of proeutectoid and pearlitic ferrites is shown.« less

Acquisition parameters optimization of a transmission electron forward scatter diffraction system in a cold-field emission scanning electron microscope for nanomaterials characterization.

PubMed

Brodusch, Nicolas; Demers, Hendrix; Trudeau, Michel; Gauvin, Raynald

2013-01-01

Transmission electron forward scatter diffraction (t-EFSD) is a new technique providing crystallographic information with high resolution on thin specimens by using a conventional electron backscatter diffraction (EBSD) system in a scanning electron microscope. In this study, the impact of tilt angle, working distance, and detector distance on the Kikuchi pattern quality were investigated in a cold-field emission scanning electron microscope (CFE-SEM). We demonstrated that t-EFSD is applicable for tilt angles ranging from -20° to -40°. Working distance (WD) should be optimized for each material by choosing the WD for which the EBSD camera screen illumination is the highest, as the number of detected electrons on the screen is directly dependent on the scattering angle. To take advantage of the best performances of the CFE-SEM, the EBSD camera should be close to the sample and oriented towards the bottom to increase forward scattered electron collection efficiency. However, specimen chamber cluttering and beam/mechanical drift are important limitations in the CFE-SEM used in this work. Finally, the importance of t-EFSD in materials science characterization was illustrated through three examples of phase identification and orientation mapping. © Wiley Periodicals, Inc.

Using a university characterization facility to educate the public about microscopes: light microscopes to SEM

NASA Astrophysics Data System (ADS)

Healy, Nancy; Henderson, Walter

2015-10-01

The National Nanotechnology Infrastructure Network (NNIN)1is an integrated partnership of 14 universities across the US funded by NSF to support nanoscale researchers. The NNIN education office is located at the Institute of Electronics and Nanotechnology at the Georgia Institute of Technology. At Georgia Tech we offer programs that integrate the facility and its resources to educate the public about nanotechnology. One event that has proved highly successful involves using microscopes in our characterization suite to educate a diverse audience about a variety of imaging instruments. As part of the annual Atlanta Science Festival (ATLSF)2 we provided an event entitled: "What's all the Buzz about Nanotechnology?" which was open to the public and advertised through a variety of methods by the ATLSF. During the event, we provided hands-on demos, cleanroom tours, and activities with three of our microscopes in our recently opened Imaging and Characterization Facility: 1. Keyence VHX-600 Digital Microscope; 2. Hitachi SU823 FE-SEM; and 3. Hitachi TM 3000. During the two hour event we had approximately 150 visitors including many families with school-aged children. Visitors were invited to bring a sample for scanning with the TM-3000. This paper will discuss how to do such an event, lessons learned, and visitor survey results.

Reducing Router Forwarding Table Size Using Aggregation and Caching

ERIC Educational Resources Information Center

Liu, Yaoqing

2013-01-01

The fast growth of global routing table size has been causing concerns that the Forwarding Information Base (FIB) will not be able to fit in existing routers' expensive line-card memory, and upgrades will lead to a higher cost for network operators and customers. FIB Aggregation, a technique that merges multiple FIB entries into one, is probably…

Prognostic Value of the Fibrosis-4 Index in Human Immunodeficiency Virus Type-1 Infected Patients Initiating Antiretroviral Therapy with or without Hepatitis C Virus

PubMed Central

Mussini, Cristina; Lorenzini, Patrizia; Puoti, Massimo; Lichtner, Miriam; Lapadula, Giuseppe; Di Giambenedetto, Simona; Antinori, Andrea; Madeddu, Giordano; Cozzi-Lepri, Alessandro; d’Arminio Monforte, Antonella; De Luca, Andrea

2015-01-01

Objective To evaluate the Fibrosis (FIB)-4 index as a predictor of major liver-related events (LRE) and liver-related death (LRD) in human immunodeficiency virus (HIV) type-1 patients initiating combination antiretroviral therapy (cART). Design Retrospective analysis of a prospective cohort study. Setting Italian HIV care centers participating to the ICONA Foundation cohort. Participants Treatment-naive patients enrolled in ICONA were selected who: initiated cART, had hepatitis C virus (HCV) serology results, were HBsAg negative, had an available FIB-4 index at cART start and during follow up. Methods Cox regression models were used to determine the association of FIB4 with the risk of major LRE (gastrointestinal bleeding, ascites, hepatic encephalopathy, hepato-renal syndrome or hepatocellular carcinoma) or LRD. Results Three-thousand four-hundred seventy-five patients were enrolled: 73.3% were males, 27.2% HCV seropositive. At baseline (time of cART initiation) their median age was 39 years, had a median CD4+ T cell count of 260 cells/uL, and median HIV RNA 4.9 log copies/mL, 65.9% had a FIB-4 <1.45, 26.4% 1.45–3.25 and 7.7% >3.25. Over a follow up of 18,662 person-years, 41 events were observed: 25 major LRE and 16 LRD (incidence rate, IR, 2.2 per 1,000 PYFU [95% confidence interval, CI 1.6–3.0]). IR was higher in HCV seropositives as compared to negatives (5.9 vs 0.5 per 1,000 PYFU). Higher baseline FIB-4 category as compared to <1.45 (FIB-4 1.45–3.25: HR 3.55, 95% CI 1.09–11.58; FIB-4>3.25: HR 4.25, 1.21–14.92) and time-updated FIB-4 (FIB-4 1.45–3.25: HR 3.40, 1.02–11.40; FIB-4>3.25: HR 21.24, 6.75–66.84) were independently predictive of major LRE/LRD, after adjusting for HIV- and HCV-related variables, alcohol consumption and type of cART. Conclusions The FIB-4 index at cART initiation, and its modification over time are risk factors for major LRE or LRD, independently of infection with HCV and could be used to monitor patients on cART. PMID:26640953

Symposium N: Materials and Devices for Thermal-to-Electric Energy Conversion

DTIC Science & Technology

2010-08-24

X - ray diffraction, transmission electron microscopy, scanning electron microscopy, and dynamic light scattering. Thermal conductivity measurements...SEM), X - ray diffraction (XRD) measurements as well as Raman spectroscopy. The results from these techniques indicate a clear modification...was examined by using scanning electron microscope (SEM; HITACHI S-4500 model) attached with an energy dispersive x - ray spectroscopy. The electrical

SPECT imaging of fibrin using fibrin-binding peptides.

PubMed

Starmans, Lucas W E; van Duijnhoven, Sander M J; Rossin, Raffaella; Aime, Silvio; Daemen, Mat J A P; Nicolay, Klaas; Grüll, Holger

2013-01-01

Noninvasive detection of fibrin in vivo using diagnostic imaging modalities may improve clinical decision-making on possible therapeutic options in atherosclerosis, cancer and thrombus-related pathologies such as pulmonary embolism and deep venous thrombosis. The aim of this study was to assess the potential of a novel (111)In-labeled fibrin-binding peptide (FibPep) to visualize thrombi in mice noninvasively using single-photon emission computed tomography (SPECT). FibPep and a negative control peptide (NCFibPep) were synthesized and their fibrin-binding properties were assessed in vitro. FibPep showed enhanced binding compared with NCFibPep to both fibrin and blood clots. FibPep bound to fibrin with a dissociation constant (K(d)) of 0.8 μ m, whereas NCFibPep displayed at least a 100-fold lower affinity towards fibrin. A FeCl3 -injury carotid artery thrombosis mouse model was used to evaluate the peptides in vivo. FibPep and NCFibPep displayed rapid blood clearance and were eliminated via the renal pathway. In vivo SPECT imaging using FibPep allowed clear visualization of thrombi. Ex vivo biodistribution showed significantly increased uptake of FibPep in the thrombus-containing carotid in comparison to the noninjured carotid (5.7 ± 0.7 and 0.6 ± 0.4% injected dose per gram (%ID g(-1)), respectively; p < 0.01; n = 4), whereas nonspecific NCFibPep did not (0.4 ± 0.2 and 0.3 ± 0.0%ID g(-1), respectively; n = 4). In conclusion, FibPep displayed high affinity towards fibrin in vitro and rapid blood clearance in vivo, and allowed sensitive detection of thrombi using SPECT imaging. Therefore, this particular imaging approach may provide a new tool to diagnose and monitor diseases such as atherosclerosis and cancer. Copyright © 2013 John Wiley & Sons, Ltd.

Biotic Interactions and Sunlight Affect Persistence of Fecal Indicator Bacteria and Microbial Source Tracking Genetic Markers in the Upper Mississippi River

PubMed Central

McMinn, Brian R.; Shanks, Orin C.; Sivaganesan, Mano; Fout, G. Shay; Ashbolt, Nicholas J.

2014-01-01

The sanitary quality of recreational waters that may be impacted by sewage is assessed by enumerating fecal indicator bacteria (FIB) (Escherichia coli and enterococci); these organisms are found in the gastrointestinal tracts of humans and many other animals, and hence their presence provides no information about the pollution source. Microbial source tracking (MST) methods can discriminate between different pollution sources, providing critical information to water quality managers, but relatively little is known about factors influencing the decay of FIB and MST genetic markers following release into aquatic environments. An in situ mesocosm was deployed at a temperate recreational beach in the Mississippi River to evaluate the effects of ambient sunlight and biotic interactions (predation, competition, and viral lysis) on the decay of culture-based FIB, as well as molecularly based FIB (Entero1a and GenBac3) and human-associated MST genetic markers (HF183 and HumM2) measured by quantitative real-time PCR (qPCR). In general, culturable FIB decayed the fastest, while molecularly based FIB and human-associated genetic markers decayed more slowly. There was a strong correlation between the decay of molecularly based FIB and that of human-associated genetic markers (r2, 0.96 to 0.98; P < 0.0001) but not between culturable FIB and any qPCR measurement. Overall, exposure to ambient sunlight may be an important factor in the early-stage decay dynamics but generally was not after continued exposure (i.e., after 120 h), when biotic interactions tended to be the only/major influential determinant of persistence. PMID:24747902

Non-alcoholic fatty liver disease fibrosis score and FIB-4 scoring system could identify patients at risk of systemic complications.

PubMed

Takahashi, Yuka; Kurosaki, Masayuki; Tamaki, Nobuharu; Yasui, Yutaka; Hosokawa, Takanori; Tsuchiya, Kaoru; Nakanishi, Hiroyuki; Itakura, Jun; Izumi, Namiki

2015-06-01

To investigate the relation between systemic complications of non-alcoholic fatty liver disease (NAFLD) and non-invasive fibrosis scores. The NAFLD fibrosis score (NFS) and FIB-4 were measured in 1559 people who underwent a complete medical checkup at our hospital and were followed for more than 3 years. Correlation between these scores and prevalence and new incidence rates of diabetes or cerebral-cardiovascular diseases were analyzed. The 1559 cases were classified into two groups using the low cut-off values of NFS and FIB-4: group 1 (≥low cut-off score with fatty liver) and group 2 (the others). In group 1, the prevalence of diabetes and cerebral-cardiovascular diseases at baseline and additional incidences during the observation period was higher compared with group 2. Diabetes at baseline in group 1 versus group 2 were 31.5% versus 3.1% (NFS, P < 0.0001), 17.0% versus 4.7% (FIB-4, P < 0.0001), and cerebral-cardiovascular diseases at baseline were 7.7% versus 2.3% (NFS, P = 0.002) and 9.0% versus 2.3% (FIB-4, P = 0.0012). New incidences of diabetes were 4.5% versus 1.2% (NFS, P = 0.034) and 3.6% versus 1.2% (FIB-4, P = 0.11), and of cerebral-cardiovascular diseases were 5.0% versus 0.9% (NFS, P = 0.0019) and 5.4% versus 0.9% (FIB-4, P = 0.0034). NFS and FIB-4 are useful to extract cases with high risk of systemic complications of NAFLD in the public. © 2014 The Japan Society of Hepatology.

[Relationship between reference values of fibrinogen and geographical factors based on neural network analysis].

PubMed

Li, Meng-Jiao; Ge, Miao; Wang, Cong-Xia; Cen, Min-Yi; Jiang, Ji-Lin; He, Jin-Wei; Lin, Qian-Yi; Liu, Xin

2016-08-20

To analyze the relationship between the reference values of fibrinogen (FIB) in healthy Chinese adults and geographical factors to provide scientific evidences for establishing the uniform standard. The reference values of FIB of 10701 Chinese healthy adults from 103 cities were collected to investigate their relationship with 18 geographical factors including spatial index, terrain index, climate index, and soil index. Geographical factors that significantly correlated with the reference values were selected for constructing the BP neural network model. The spatial distribution map of the reference value of FIB of healthy Chinese adults was fitted by disjunctive kriging interpolation. We used the 5-layer neural network and selected 2000 times of training covering 11 hidden layers to build the simulation rule for simulating the relationship between FIB and geographical environmental factors using the MATLAB software. s The reference value of FIB in healthy Chinese adults was significantly correlated with the latitude, sunshine duration, annual average temperature, annual average relative humidity, annual precipitation, annual range of air temperature, average annual soil gravel content, and soil cation exchange capacity (silt). The artificial neural networks were created to analyze the simulation of the selected indicators of geographical factors. The spatial distribution map of the reference values of FIB in healthy Chinese adults showed a distribution pattern that FIB levels were higher in the South and lower in the North, and higher in the East and lower in the West. When the geographical factors of a certain area are known, the reference values of FIB in healthy Chinese adults can be obtained by establishing the neural network mode or plotting the spatial distribution map.

Fecal indicator bacteria and Salmonella in ponds managed as bird habitat, San Francisco Bay, California, USA

USGS Publications Warehouse

Shellenbarger, G.G.; Athearn, N.D.; Takekawa, John Y.; Boehm, A.B.

2008-01-01

Throughout the world, coastal resource managers are encouraging the restoration of previously modified coastal habitats back into wetlands and managed ponds for their ecosystem value. Because many coastal wetlands are adjacent to urban centers and waters used for human recreation, it is important to understand how wildlife can affect water quality. We measured fecal indicator bacteria (FIB) concentrations, presence/absence of Salmonella, bird abundance, and physico-chemical parameters in two coastal, managed ponds and adjacent sloughs for 4 weeks during the summer and winter in 2006. We characterized the microbial water quality in these waters relative to state water-quality standards and examined the relationship between FIB, bird abundance, and physico-chemical parameters. A box model approach was utilized to determine the net source or sink of FIB in the ponds during the study periods. FIB concentrations often exceeded state standards, particularly in the summer, and microbial water quality in the sloughs was generally lower than in ponds during both seasons. Specifically, the inflow of water from the sloughs to the ponds during the summer, more so than waterfowl use, appeared to increase the FIB concentrations in the ponds. The box model results suggested that the ponds served as net wetland sources and sinks for FIB, and high bird abundances in the winter likely contributed to net winter source terms for two of the three FIB in both ponds. Eight serovars of the human pathogen Salmonella were isolated from slough and pond waters, although the source of the pathogen to these wetlands was not identified. Thus, it appeared that factors other than bird abundance were most important in modulating FIB concentrations in these ponds.

Diagnostic Usefulness of APRI and FIB-4 for the Prediction of Liver Fibrosis After Liver Transplantation in Patients Infected with Hepatitis C Virus.

PubMed

Imai, H; Kamei, H; Onishi, Y; Ishizu, Y; Ishigami, M; Goto, H; Ogura, Y

2018-06-01

Aspartate transaminase-to-platelet ratio index (APRI) and fibrosis-4 (FIB-4) are well known as representative indirect serum biomarkers related to liver fibrosis. The usefulness of these markers for the diagnosis of liver fibrosis after liver transplantation (LT) in hepatitis C virus (HCV)-infected patients and the influence of splenectomy were investigated. From June 2003 to May 2014, 31 HCV-infected patients who underwent LT and postoperative follow-up liver biopsies were included in this study. The association between liver fibrosis and serum biomarkers and the influence of splenectomy on APRI and FIB-4 were also investigated. A total of 195 biopsy specimens were collected, and liver fibrosis was identified as: F0, 59.7%; F1, 34.1%; and F2, 6.3%. Both APRI and FIB-4 were significantly higher in patients who showed F1 and F2 in liver biopsy specimen than F0 (P values, .009 and .022, respectively); sensitivity and specificity of APRI were, respectively, 63.4% and 66.7%, and those of FIB-4 were 57.7% and 69.6%. In 11 patients (35.5%) who underwent splenectomy at the time of LT, the cutoff values for APRI and FIB-4 were 0.61 and 1.41, which were significantly lower than the corresponding values (1.00 and 3.64) of patients without splenectomy. APRI and FIB-4 could effectively estimate liver fibrosis after LT for HCV-related liver disease. For LT patients with splenectomy, APRI and FIB-4 were also useful to estimate liver fibrosis, but the standard values should be adjusted lower than those for patients without splenectomy. Copyright © 2018 Elsevier Inc. All rights reserved.

FIB-4 index for assessing the prognosis of hepatocellular carcinoma in patients with Child-Pugh class A liver function.

PubMed

Ito, Takanori; Kumada, Takashi; Toyoda, Hidenori; Tada, Toshifumi

2015-07-01

We evaluated the prognosis of hepatocellular carcinoma (HCC) patients with Child-Pugh (C-P) class A based on FIB-4 index, which is a liver fibrosis marker. A total of 915 HCC patients with C-P class A were investigated. We assessed the prognosis using FIB-4 index, and factors associated with survival rates were analyzed in these patients. When patients were categorized according to FIB-4 index as <2.0 (n = 93), ≥ 2.0 and <4.0 (n = 311), and ≥ 4.0 (n = 511), survival rates at 5 years were 70.5% [95% confidence interval (CI) 59.0-79.9], 56.4% (95% CI 50.1-62.5), and 47.1% (95% CI 42.2-52.1), respectively. Patients with FIB-4 index <2.0 had a higher survival rate than the other groups (≥ 4.0 vs ≥ 2.0 and <4.0, p = 0.010; ≥ 2.0 and <4.0 vs <2.0, p = 0.028). We were able to predict prognosis in patients with C-P score 5 by FIB-4 index, but survival rate did not significantly differ in patients with C-P score 6. Multivariate analysis identified C-P score, FIB-4 index [≥ 2.0 and <4.0; hazard ratios (HRs) 1.638 (95% CI 1.084-2.474); p = 0.019/≥ 4.0; HR 1.828 (95% CI 1.217-2.744); p = 0.004], Lens culinaris agglutinin-reactive α-fetoprotein, tumor size, number, vascular invasion, antiviral therapy, and hepatectomy as independent predictive factors for survival. The FIB-4 index is useful for assessing prognosis in HCC patients with C-P class A, especially those with C-P score 5.

Three-dimensional cytomorphology in fine needle aspiration biopsy of medullary thyroid carcinoma.

PubMed

Chang, T C; Lai, S M; Wen, C Y; Hsiao, Y L; Huang, S H

2001-01-01

To elucidate three-dimensional (3-D) cytomorphology in fine needle aspiration biopsy (FNAB) of medullary thyroid carcinoma (MTC). ENAB was performed on tumors from five patients with MTC. The aspirate was stained and observed under a light microscope (LM). The aspirate was also fixed, dehydrated, critical point dried, spattered with gold ions and observed with a scanning electron microscope (SEM). For transmission electron microscopy (TEM), the specimen was fixed, dehydrated, embedded in an Epon mixture, cut with an ultramicrotome, mounted on copper grids, electron doubly stained with uranium acetate and lead citrate, and observed with TEM. Findings under SEM were correlated with those under LM and TEM. Under SEM, 3-D cytomorphology of MTC displayed a disorganized cellular arrangement with indistinct cell borders in three cases. The cell surface was uneven and had granular protrusions that corresponded to secretory granules observed under TEM. In one case with multiple endocrine neoplasia type IIB, there were abundant granules on the cell surface. In one case of sporadic MTC with multinucleated tumor giant cells and small cells, granular protrusions also were noted on the cell surface. Granular protrusion was a characteristic finding in FNAB of MTC tinder SEM and might be helpful in the differential diagnosis.

Optical sectioning and 3D reconstructions as an alternative to scanning electron microscopy for analysis of cell shape.

PubMed

Landis, Jacob B; Ventura, Kayla L; Soltis, Douglas E; Soltis, Pamela S; Oppenheimer, David G

2015-04-01

Visualizing flower epidermal cells is often desirable for investigating the interaction between flowers and their pollinators, in addition to the broader range of ecological interactions in which flowers are involved. We developed a protocol for visualizing petal epidermal cells without the limitations of the commonly used method of scanning electron microscopy (SEM). Flower material was collected and fixed in glutaraldehyde, followed by dehydration in an ethanol series. Flowers were dissected to collect petals, and subjected to a Histo-Clear series to remove the cuticle. Material was then stained with aniline blue, mounted on microscope slides, and imaged using a compound fluorescence microscope to obtain optical sections that were reconstructed into a 3D image. This optical sectioning method yielded high-quality images of the petal epidermal cells with virtually no damage to cells. Flowers were processed in larger batches than are possible using common SEM methods. Also, flower size was not a limiting factor as often observed in SEM studies. Flowers up to 5 cm in length were processed and mounted for visualization. This method requires no special equipment for sample preparation prior to imaging and should be seen as an alternative method to SEM.

Real-time observation of FIB-created dots and ripples on GaAs

NASA Astrophysics Data System (ADS)

Rose, F.; Fujita, H.; Kawakatsu, H.

2008-01-01

We report a phenomenological study of Ga dots and ripples created by a focused ion beam (FIB) on the GaAs(001) surface. Real-time observation of dot diffusion and ripple formation was made possible by recording FIB movies. In the case of FIB irradiation with a 40 nA current of Ga+ ions accelerated under 40 kV with an incidence angle of θ = 30°, increasing ion dose gives rise to three different regimes. In Regime 1, dots with lateral sizes in the range 50-460 nm are formed. Dots diffuse under continuous sputtering. In Regime 2, dots self-assemble into Bradley and Harper (BH) type ripples with a pseudo-period of λ = 1150 ± 25 nm. In Regime 3, ripples are eroded and the surface topology evolves into microplanes. In the case of normal incidence, FIB sputtering leads only to the formation of dots, without surface rippling.

Dopant concentration dependent growth of Fe:ZnO nanostructures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sahai, Anshuman; Goswami, Navendu, E-mail: navendugoswami@gmail.com

2016-05-23

Systematic investigations of structural properties of 1-10% Fe doped ZnO nanostructure (Fe:ZnO NS) prepared via chemical precipitation method have been reported. Structural properties were probed thoroughly employing scanning electron microscope (SEM) and transmission electron microscope (TEM), energy dispersive X-ray (EDAX) analysis and X-ray diffraction (XRD). Morphological transformation of nanostructures (NS) with Fe incorporation is evident in SEM/TEM images. Nanoparticles (NP) obtained with 1% Fe, evolve to nanorods (NR) for 3% Fe; NR transform to nanocones (NC) (for 5% and 7% Fe) and finally NC transform to nanoflakes (NF) at 10% Fe. Morover, primary phase of Zn{sub 1-x}Fe{sub x}O along withmore » secondary phases of ZnFe{sub 2}O{sub 4} and Fe{sub 2}O{sub 3} were also revealed through XRD measurements. Based on collective XRD, SEM, TEM, and EDAX interpretations, a model for morphological evolution of NS was proposed and the pivotal role of Fe dopant was deciphered.« less

An ultrastructural study on corkscrew hairs and cigarette-ash-shaped hairs observed by dermoscopy of tinea capitis.

PubMed

Lu, Mao; Ran, Yuping; Dai, Yaling; Lei, Song; Zhang, Chaoliang; Zhuang, Kaiwen; Hu, Wenying

2016-01-01

This study was aimed to explain the formation mechanisms of corkscrew hairs and cigarette-ash-shaped hairs observed by dermoscopy of tinea capitis. In the present work, the ultrastructure of the involved hairs collected from a girl with tinea capitis caused by Trichophyton violaceum was observed by scanning electron microscope (SEM) and transmission electron microscope (TEM). SEM observation of the corkscrew hair revealed bent hair shaft and asymmetrically disrupted cuticle layer. TEM findings demonstrated the hair shaft became weak. The corkscrew hairs closely covered by scales on the scalp were observed under dermoscopy. We speculate that the formation of corkscrew hairs is a result of a combination of internal damage due to hair degradation by T. violaceum and external resistance due to scales covering the hair. SEM observation of the cigarette-ash-shaped hair revealed irregularly disrupted and incompact end, which might represent the stump of the broken corkscrew hair after treatment. © Wiley Periodicals, Inc.

Laboratory characterization of shale pores

NASA Astrophysics Data System (ADS)

Nur Listiyowati, Lina

2018-02-01

To estimate the potential of shale gas reservoir, one needs to understand the characteristics of pore structures. Characterization of shale gas reservoir microstructure is still a challenge due to ultra-fine grained micro-fabric and micro level heterogeneity of these sedimentary rocks. The sample used in the analysis is a small portion of any reservoir. Thus, each measurement technique has a different result. It raises the question which methods are suitable for characterizing pore shale. The goal of this paper is to summarize some of the microstructure analysis tools of shale rock to get near-real results. The two analyzing pore structure methods are indirect measurement (MIP, He, NMR, LTNA) and direct observation (SEM, TEM, Xray CT). Shale rocks have a high heterogeneity; thus, it needs multiscale quantification techniques to understand their pore structures. To describe the complex pore system of shale, several measurement techniques are needed to characterize the surface area and pore size distribution (LTNA, MIP), shapes, size and distribution of pore (FIB-SEM, TEM, Xray CT), and total porosity (He pycnometer, NMR). The choice of techniques and methods should take into account the purpose of the analysis and also the time and budget.

Formation and evolution of ripples on ion-irradiated semiconductor surfaces

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kang, M.; Wu, J. H.; Ye, W.

We have examined the formation and evolution of ripples on focused-ion-beam (FIB) irradiated compound semiconductor surfaces. Using initially normal-incidence Ga{sup +} FIB irradiation of InSb, we tuned the local beam incidence angle (θ{sub eff}) by varying the pitch and/or dwell time. For single-pass FIB irradiation, increasing θ{sub eff} induces morphological evolution from pits and islands to ripples to featureless surfaces. Multiple-pass FIB irradiation of the rippled surfaces at a fixed θ{sub eff} leads to island formation on the ripple crests, followed by nanorod (NR) growth. This ripple-NR transition provides an alternative approach for achieving dense arrays of NRs.

Impacts of beach wrack removal via grooming on surf zone water quality.

PubMed

Russell, Todd L; Sassoubre, Lauren M; Zhou, Christina; French-Owen, Darien; Hassaballah, Abdulrahman; Boehm, Alexandria B

2014-02-18

Fecal indicator bacteria (FIB) are used to assess the microbial water quality of recreational waters. Increasingly, nonfecal sources of FIB have been implicated as causes of poor microbial water quality in the coastal environment. These sources are challenging to quantify and difficult to remediate. The present study investigates one nonfecal FIB source, beach wrack (decaying aquatic plants), and its impacts on water quality along the Central California coast. The prevalence of FIB on wrack was studied using a multibeach survey, collecting wrack throughout Central California. The impacts of beach grooming, to remove wrack, were investigated at Cowell Beach in Santa Cruz, California using a long-term survey (two summers, one with and one without grooming) and a 48 h survey during the first ever intensive grooming event. FIB were prevalent on wrack but highly variable spatially and temporally along the nine beaches sampled in Central California. Beach grooming was generally associated with either no change or a slight increase in coastal FIB concentrations and increases in surf zone turbidity and silicate, phosphate, and dissolved inorganic nitrogen concentrations. The findings suggest that beach grooming for wrack removal is not justified as a microbial pollution remediation strategy.

Evaluation of 111In-labeled EPep and FibPep as tracers for fibrin SPECT imaging.

PubMed

Starmans, Lucas W E; van Duijnhoven, Sander M J; Rossin, Raffaella; Berben, Monique; Aime, Silvio; Daemen, Mat J A P; Nicolay, Klaas; Grüll, Holger

2013-11-04

Fibrin targeting is an attractive strategy for nuclear imaging of thrombosis, atherosclerosis and cancer. Recently, FibPep, an (111)In-labeled fibrin-binding peptide, was established as a tracer for fibrin SPECT imaging and was reported to allow sensitive detection of minute thrombi in mice using SPECT. In this study, we developed EPep, a novel (111)In-labeled fibrin-binding peptide containing the fibrin-binding domain of the clinically verified EP-2104R peptide, and sought to compare the potential of EPep and FibPep as tracers for fibrin SPECT imaging. In vitro, both EPep and FibPep showed high stability in serum, but were less stable in liver and kidney homogenate assays. Both peptide probes displayed comparable affinities toward human and mouse derived fibrin (Kd ≈ 1 μM), and similarly to FibPep, EPep showed fast blood clearance, low nontarget uptake and high thrombus uptake (6.8 ± 1.2% ID g(-1)) in a mouse carotid artery thrombosis model. Furthermore, EPep showed a similar affinity toward rat derived fibrin (Kd ≈ 1 μM), displayed high thrombus uptake in a rat carotid artery thrombosis model (0.74 ± 0.39% ID g(-1)), and allowed sensitive detection of thrombosis in rats using SPECT. In contrast, FibPep displayed a significantly lower affinity toward rat derived fibrin (Kd ≈ 14 μM) and low uptake in rat thrombi (0.06 ± 0.02% ID g(-1)) and did not allow clear visualization of carotid artery thrombosis in rats using SPECT. These results were confirmed ex vivo by autoradiography, which showed a 7-fold higher ratio of activity in the thrombus over the contralateral carotid artery for EPep in comparison to FibPep. These findings suggest that the FibPep binding fibrin epitope is not fully homologous between humans and rats, and that preclinical rat models of disease should not be employed to gauge the clinical potential of FibPep. In conclusion, both peptides showed approximately similar metabolic stability and affinity toward human and mouse derived fibrin, and displayed high thrombus uptake in a mouse carotid artery thrombosis model. Therefore, both EPep and FibPep are promising fibrin targeted tracers for translation into clinical settings to serve as novel tools for molecular imaging of fibrin.

Serial sectioning methods for 3D investigations in materials science.

PubMed

Zankel, Armin; Wagner, Julian; Poelt, Peter

2014-07-01

A variety of methods for the investigation and 3D representation of the inner structure of materials has been developed. In this paper, techniques based on slice and view using scanning microscopy for imaging are presented and compared. Three different methods of serial sectioning combined with either scanning electron or scanning ion microscopy or atomic force microscopy (AFM) were placed under scrutiny: serial block-face scanning electron microscopy, which facilitates an ultramicrotome built into the chamber of a variable pressure scanning electron microscope; three-dimensional (3D) AFM, which combines an (cryo-) ultramicrotome with an atomic force microscope, and 3D FIB, which delivers results by slicing with a focused ion beam. These three methods complement one another in many respects, e.g., in the type of materials that can be investigated, the resolution that can be obtained and the information that can be extracted from 3D reconstructions. A detailed review is given about preparation, the slice and view process itself, and the limitations of the methods and possible artifacts. Applications for each technique are also provided. Copyright © 2014 Elsevier Ltd. All rights reserved.

Simulation and Characterization of a Miniaturized Scanning Electron Microscope

NASA Technical Reports Server (NTRS)

Gaskin, Jessica A.; Jerman, Gregory A.; Medley, Stephanie; Gregory, Don; Abbott, Terry O.; Sampson, Allen R.

2011-01-01

A miniaturized Scanning Electron Microscope (mSEM) for in-situ lunar investigations is being developed at NASA Marshall Space Flight Center with colleagues from the University of Alabama in Huntsville (UAH), Advanced Research Systems (ARS), the University of Tennessee in Knoxville (UTK) and Case Western Reserve University (CWRU). This effort focuses on the characterization of individual components of the mSEM and simulation of the complete system. SEMs can provide information on the size, shape, morphology and chemical composition of lunar regolith. Understanding these basic properties will allow us to better estimate the challenges associated with In-Situ Resource Utilization and to improve our basic science knowledge of the lunar surface (either precluding the need for sample return or allowing differentiation of unique samples to be returned to Earth.) The main components of the mSEM prototype includes: a cold field emission electron gun (CFEG), focusing lens, deflection/scanning system and backscatter electron detector. Of these, the electron gun development is of particular importance as it dictates much of the design of the remaining components. A CFEG was chosen for use with the lunar mSEM as its emission does not depend on heating of the tungsten emitter (lower power), it offers a long operation lifetime, is orders of magnitude brighter than tungsten hairpin guns, has a small source size and exhibits low beam energy spread.

Developing an Effective Model for Shale Gas Flow in Nano-scale Pore Clusters based on FIB-SEM Images

NASA Astrophysics Data System (ADS)

Jiang, W. B.; Lin, M.; Yi, Z. X.; Li, H. S.

2016-12-01

Nano-scale pores existed in the form of clusters are the controlling void space in shale gas reservoir. Gas transport in nanopores which has a significant influence on shale gas' recoverability displays multiple transport regimes, including viscous, slippage flow and Knudsen diffusion. In addition, it is also influenced by pore space characteristics. For convenience and efficiency consideration, it is necessary to develop an upscaling model from nano pore to pore cluster scale. Existing models are more like framework functions that provide a format, because the parameters that represent pore space characteristics are underdetermined and may have multiple possibilities. Therefore, it is urgent to make them clear and obtained a model that is closer to reality. FIB-SEM imaging technology is able to acquire three dimensional images with nanometer resolution that nano pores can be visible. Based on the images of two shale samples, we used a high-precision pore network extraction algorithm to generate equivalent pore networks and simulate multiple regime (non-Darcy) flow in it. Several structural parameters can be obtained through pore network modelling. It is found that although the throat-radius distributions are very close, throat flux-radius distributions of different samples can be divided into two categories. The variation of tortuosity with pressure and the overall trend of throat-flux distribution changes with pressure are disclosed. A deeper understanding of shale gas flow in nano-scale pore clusters is obtained. After all, an upscaling model that connects absolute permeability, apparent permeability and other characteristic parameters is proposed, and the best parameter scheme considering throat number-radius distribution and flowing porosity for this model is selected out of three schemes based on pore scale results, and it can avoid multiple-solution problem and is useful in reservoir modelling and experiment result analysis, etc. This work is supported by the Strategic Priority Research Program of the Chinese Academy of Sciences (XDB10020302), the National Natural Science Foundation of China (41574129), the Key Instrument Developing Project of the CAS (ZDYZ2012-1-08-02), the 973 Program (2014CB239004).

Analysis of packing microstructure and wall effects in a narrow-bore ultrahigh pressure liquid chromatography column using focused ion-beam scanning electron microscopy.

PubMed

Reising, Arved E; Schlabach, Sabine; Baranau, Vasili; Stoeckel, Daniela; Tallarek, Ulrich

2017-09-01

Column wall effects are well recognized as major limiting factor in achieving high separation efficiency in HPLC. This is especially important for modern analytical columns packed with small particles, where wall effects dominate the band broadening. Detailed knowledge about the packing microstructure of packed analytical columns has so far not been acquired. Here, we present the first three-dimensional reconstruction protocol for these columns utilizing focused ion-beam scanning electron microscopy (FIB-SEM) on a commercial 2.1mm inner diameter×50mm length narrow-bore analytical column packed with 1.7μm bridged-ethyl hybrid silica particles. Two sections from the packed bed are chosen for reconstruction by FIB-SEM: one from the bulk packing region of the column and one from its critical wall region. This allows quantification of structural differences between the wall region and the center of the bed due to effects induced by the hard, confining column wall. Consequences of these effects on local flow velocity in the column are analyzed with flow simulations utilizing the lattice-Boltzmann method. The reconstructions of the bed structures reveal significant structural differences in the wall region (extending radially over approximately 62 particle diameters) compared to the center of the column. It includes the local reduction of the external porosity by up to 10% and an increase of the mean particle diameter by up to 3%, resulting in a decrease of the local flow velocity by up to 23%. In addition, four (more ordered) layers of particles in the direct vicinity of the column wall induce local velocity fluctuations by up to a factor of three regarding the involved velocity amplitudes. These observations highlight the impact of radial variations in packing microstructure on band migration and column performance. This knowledge on morphological peculiarities of column wall effects helps guiding us towards further optimization of the packing process for analytical HPLC columns. Copyright © 2017 Elsevier B.V. All rights reserved.

An Image-based Micro-continuum Pore-scale Model for Gas Transport in Organic-rich Shale

NASA Astrophysics Data System (ADS)

Guo, B.; Tchelepi, H.

2017-12-01

Gas production from unconventional source rocks, such as ultra-tight shales, has increased significantly over the past decade. However, due to the extremely small pores ( 1-100 nm) and the strong material heterogeneity, gas flow in shale is still not well understood and poses challenges for predictive field-scale simulations. In recent years, digital rock analysis has been applied to understand shale gas transport at the pore-scale. An issue with rock images (e.g. FIB-SEM, nano-/micro-CT images) is the so-called "cutoff length", i.e., pores and heterogeneities below the resolution cannot be resolved, which leads to two length scales (resolved features and unresolved sub-resolution features) that are challenging for flow simulations. Here we develop a micro-continuum model, modified from the classic Darcy-Brinkman-Stokes framework, that can naturally couple the resolved pores and the unresolved nano-porous regions. In the resolved pores, gas flow is modeled with Stokes equation. In the unresolved regions where the pore sizes are below the image resolution, we develop an apparent permeability model considering non-Darcy flow at the nanoscale including slip flow, Knudsen diffusion, adsorption/desorption, surface diffusion, and real gas effect. The end result is a micro-continuum pore-scale model that can simulate gas transport in 3D reconstructed shale images. The model has been implemented in the open-source simulation platform OpenFOAM. In this paper, we present case studies to demonstrate the applicability of the model, where we use 3D segmented FIB-SEM and nano-CT shale images that include four material constituents: organic matter, clay, granular mineral, and pore. In addition to the pore structure and the distribution of the material constituents, we populate the model with experimental measurements (e.g. size distribution of the sub-resolution pores from nitrogen adsorption) and parameters from the literature and identify the relative importance of different physics on gas production. Overall, the micro-continuum model provides a novel tool for digital rock analysis of organic-rich shale.

A scanning electron microscope technique for studying the sclerites of Cichlidogyrus.

PubMed

Fannes, Wouter; Vanhove, Maarten P M; Huyse, Tine; Paladini, Giuseppe

2015-05-01

The genus Cichlidogyrus (Monogenea: Ancyrocephalidae) includes more than 90 species, most of which are gill parasites of African cichlid fishes. Cichlidogyrus has been studied extensively in recent years, but scanning electron microscope (SEM) investigations of the isolated hard parts have not yet been undertaken. In this paper, we describe a method for isolating and scanning the sclerites of individual Cichlidogyrus worms. Twenty-year-old, formol-fixed specimens of Cichlidogyrus casuarinus were subjected to proteinase K digestion in order to release the sclerites from the surrounding soft tissues. SEM micrographs of the haptoral sclerites and the male copulatory organ are presented. The ability to digest formol-fixed specimens makes this method a useful tool for the study of historical museum collections.

Effect of Specimen Thickness on the Creep Response of a Ni-Based Single Crystal Superalloy (PREPRINT)

DTIC Science & Technology

2012-08-01

unlimited 3.1.2. Fractography Figure 5: SEM images of a 3.18mm thick sheet specimen tested at 760◦C/758MPa. (a) The region near the fracture surface... fractography using secondary electron imaging (SE) in a scanning electron microscope (SEM). No surface oxidation was observed at this temperature. The...ruptured after 210 hours. 3.2.3. Fractography The SEM image of the reconstructed creep ruptured specimen with thickness h = 3.18mm is shown in Fig. 18a

Performance of signal-to-noise ratio estimation for scanning electron microscope using autocorrelation Levinson-Durbin recursion model.

PubMed

Sim, K S; Lim, M S; Yeap, Z X

2016-07-01

A new technique to quantify signal-to-noise ratio (SNR) value of the scanning electron microscope (SEM) images is proposed. This technique is known as autocorrelation Levinson-Durbin recursion (ACLDR) model. To test the performance of this technique, the SEM image is corrupted with noise. The autocorrelation function of the original image and the noisy image are formed. The signal spectrum based on the autocorrelation function of image is formed. ACLDR is then used as an SNR estimator to quantify the signal spectrum of noisy image. The SNR values of the original image and the quantified image are calculated. The ACLDR is then compared with the three existing techniques, which are nearest neighbourhood, first-order linear interpolation and nearest neighbourhood combined with first-order linear interpolation. It is shown that ACLDR model is able to achieve higher accuracy in SNR estimation. © 2016 The Authors Journal of Microscopy © 2016 Royal Microscopical Society.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bekar, Kursat B; Miller, Thomas Martin; Patton, Bruce W

The characteristic X-rays produced by the interactions of the electron beam with the sample in a scanning electron microscope (SEM) are usually captured with a variable-energy detector, a process termed energy dispersive spectrometry (EDS). The purpose of this work is to exploit inverse simulations of SEM-EDS spectra to enable rapid determination of sample properties, particularly elemental composition. This is accomplished using penORNL, a modified version of PENELOPE, and a modified version of the traditional Levenberg Marquardt nonlinear optimization algorithm, which together is referred to as MOZAIK-SEM. The overall conclusion of this work is that MOZAIK-SEM is a promising method formore » performing inverse analysis of X-ray spectra generated within a SEM. As this methodology exists now, MOZAIK-SEM has been shown to calculate the elemental composition of an unknown sample within a few percent of the actual composition.« less

Electrical characterization of FIB processed metal layers for reliable conductive-AFM on ZnO microstructures

NASA Astrophysics Data System (ADS)

Pea, M.; Maiolo, L.; Giovine, E.; Rinaldi, A.; Araneo, R.; Notargiacomo, A.

2016-05-01

We report on the conductive-atomic force microscopy (C-AFM) study of metallic layers in order to find the most suitable configuration for electrical characterization of individual ZnO micro-pillars fabricated by focused ion beam (FIB). The electrical resistance between the probe tip and both as deposited and FIB processed metal layers (namely, Cr, Ti, Au and Al) has been investigated. Both chromium and titanium evidenced a non homogenous and non ohmic behaviour, non negligible scanning probe induced anodic oxidation associated to electrical measurements, and after FIB milling they exhibited significantly higher tip-sample resistance. Aluminium had generally a more apparent non conductive behaviour. Conversely, gold films showed very good tip-sample conduction properties being less sensitive to FIB processing than the other investigated metals. We found that a reliable C-AFM electrical characterization of ZnO microstructures obtained by FIB machining is feasible by using a combination of metal films as top contact layer. An Au/Ti bilayer on top of ZnO was capable to sustain the FIB fabrication process and to form a suitable ohmic contact to the semiconductor, allowing for reliable C-AFM measurement. To validate the consistency of this approach, we measured the resistance of ZnO micropillars finding a linear dependence on the pillar height, as expected for an ohmic conductor, and evaluated the resistivity of the material. This procedure has the potential to be downscaled to nanometer size structures by a proper choice of metal films type and thickness.

Diagnostic accuracy of APRI and FIB-4 for predicting hepatitis B virus-related liver fibrosis accompanied with hepatocellular carcinoma.

PubMed

Xiao, Guangqin; Zhu, Feng; Wang, Min; Zhang, Hang; Ye, Dawei; Yang, Jiayin; Jiang, Li; Liu, Chang; Yan, Lunan; Qin, Renyi

2016-10-01

Aspartate aminotransferase to platelet ratio index (APRI) and the fibrosis index based on four factors (FIB-4) are the two most focused non-invasive models to assess liver fibrosis. We aimed to examine the validity of these two models for predicting hepatitis B virus (HBV)-related liver fibrosis accompanied with hepatocellular carcinoma (HCC). We enrolled HBV-infected patients with liver cancer who had received hepatectomy. The accuracy of APRI and FIB-4 for diagnosing liver fibrosis was assessed based on their sensitivity, specificity, diagnostic efficiency, positive predictive value (PPV), negative predictive value (NPV), kappa (κ) value and area under the receiver-operating characteristic curve (AUC). Finally 2176 patients were included, with 1682 retrospective subjects and 494 prospective subjects. APRI (rs=0.310) and FIB-4 (rs=0.278) were positively correlated with liver fibrosis. And χ(2) analysis demonstrated that APRI and FIB-4 values correlated with different levels of liver fibrosis with all P values less than 0.01. The AUC values for APRI and FIB-4 were 0.685 and 0.626 (P=0.73) for predicting significant fibrosis, 0.681 and 0.648 (P=0.81) for differentiation of advanced fibrosis and 0.676 and 0.652 (P=0.77) for diagnosing cirrhosis. APRI and FIB-4 correlate with liver fibrosis. However these two models have low accuracy for predicting HBV-related liver fibrosis in HCC patients. Copyright © 2016. Published by Elsevier Ltd.

Snow crystal imaging using scanning electron microscopy: III. Glacier ice, snow and biota

USGS Publications Warehouse

Rango, A.; Wergin, W.P.; Erbe, E.F.; Josberger, E.G.

2000-01-01

Low-temperature scanning electron microscopy (SEM) was used to observe metamorphosed snow, glacial firn, and glacial ice obtained from South Cascade Glacier in Washington State, USA. Biotic samples consisting of algae (Chlamydomonas nivalis) and ice worms (a species of oligochaetes) were also collected and imaged. In the field, the snow and biological samples were mounted on copper plates, cooled in liquid nitrogen, and stored in dry shipping containers which maintain a temperature of -196??C. The firn and glacier ice samples were obtained by extracting horizontal ice cores, 8 mm in diameter, at different levels from larger standard glaciological (vertical) ice cores 7.5 cm in diameter. These samples were cooled in liquid nitrogen and placed in cryotubes, were stored in the same dry shipping container, and sent to the SEM facility. In the laboratory, the samples were sputter coated with platinum and imaged by a low-temperature SEM. To image the firn and glacier ice samples, the cores were fractured in liquid nitrogen, attached to a specimen holder, and then imaged. While light microscope images of snow and ice are difficult to interpret because of internal reflection and refraction, the SEM images provide a clear and unique view of the surface of the samples because they are generated from electrons emitted or reflected only from the surface of the sample. In addition, the SEM has a great depth of field with a wide range of magnifying capabilities. The resulting images clearly show the individual grains of the seasonal snowpack and the bonding between the snow grains. Images of firn show individual ice crystals, the bonding between the crystals, and connected air spaces. Images of glacier ice show a crystal structure on a scale of 1-2 mm which is considerably smaller than the expected crystal size. Microscopic air bubbles, less than 15 ??m in diameter, clearly marked the boundaries between these crystal-like features. The life forms associated with the glacier were easily imaged and studied. The low-temperature SEM sample collecting and handling methods proved to be operable in the field; the SEM analysis is applicable to glaciological studies and reveals details unattainable by conventional light microscopic methods.Low temperature scanning electron microscopy (SEM) was used to observe metamorphosed snow, glacial firn, and glacial ice obtained from South Cascade Glacier in Washington State, USA. Biotic samples consisting of algae and ice worms were also collected and imaged. The SEM images provide a clear and unique view of the surface of the samples because they are generated from electrons emitted or reflected only from the surface of the sample. The SEM has a great depth of field with a wide range of magnifying capabilities.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yashchuk, V.V.; Conley, R.; Anderson, E.H.

Verification of the reliability of metrology data from high quality X-ray optics requires that adequate methods for test and calibration of the instruments be developed. For such verification for optical surface profilometers in the spatial frequency domain, a modulation transfer function (MTF) calibration method based on binarypseudo-random (BPR) gratings and arrays has been suggested and and proven to be an effective calibration method for a number of interferometric microscopes, a phase shifting Fizeau interferometer, and a scatterometer. Here we describe the details of development of binarypseudo-random multilayer (BPRML) test samples suitable for characterization of scanning (SEM) and transmission (TEM) electronmore » microscopes. We discuss the results of TEM measurements with the BPRML test samples fabricated from a WiSi{sub 2}/Si multilayer coating with pseudo-randomly distributed layers. In particular, we demonstrate that significant information about the metrological reliability of the TEM measurements can be extracted even when the fundamental frequency of the BPRML sample is smaller than the Nyquist frequency of the measurements. The measurements demonstrate a number of problems related to the interpretation of the SEM and TEM data. Note that similar BPRML testsamples can be used to characterize X-ray microscopes. Corresponding work with X-ray microscopes is in progress.« less

Microscopic Observation of the Side Surface of Dynamically-Tensile-Fractured 6061-T6 and 2219-T87 Aluminum Alloys with Pre-Fatigue

NASA Astrophysics Data System (ADS)

Itabashi, Masaaki; Nakajima, Shigeru; Fukuda, Hiroshi

After unexpected failure of metallic structure, microscopic investigation will be performed. Generally, such an investigation is limited to search striation pattern with a SEM (scanning electron microscope). But, when the cause of the failure was not severe repeated stress, this investigation is ineffective. In this paper, new microscopic observation technique is proposed to detect low cycle fatigue-impact tensile loading history. Al alloys, 6061-T6 and 2219-T87, were fractured in dynamic tension, after severe pre-fatigue. The side surface of the fractured specimens was observed with a SEM. Neighboring fractured surface, many opened cracks on the side surface have been generated. For each specimen, the number of the cracks was counted together with information of individual sizes and geometric features. For 6061-T6 alloy specimen with the pre-fatigue, the number of the cracks is greater than that for the specimen without the pre-fatigue. For 2219-T87 alloy, the same tendency can be found after a certain screening of the crack counting. Therefore, the crack counting technique may be useful to detect the existence of the pre-fatigue from the dynamically fractured specimen surface.

Fabrication of large area plasmonic nanoparticle grating structure on silver halide based transmission electron microscope film and its application as a surface enhanced Raman spectroscopy substrate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sudheer,, E-mail: sudheer@rrcat.gov.in; Tiwari, P.; Singh, M. N.

The plasmonic responses of silver nanoparticle grating structures of different periods made on silver halide based electron microscope film are investigated. Raster scan of the conventional scanning electron microscope (SEM) is used to carry out electron beam lithography for fabricating the plasmonic nanoparticle grating (PNG) structures. Morphological characterization of the PNG structures, carried out by the SEM and the atomic force microscope, indicates that the depth of the groove decreases with a decrease in the grating period. Elemental characterization performed by the energy dispersive spectroscopy and the x-ray diffraction shows the presence of nanoparticles of silver in the PNG grating.more » The optical characterization of the gratings shows that the localized surface plasmon resonance peak shifts from 366 to 378 nm and broadens with a decrease in grating period from 10 to 2.5 μm. The surface enhanced Raman spectroscopy of the Rhodamine-6G dye coated PNG structure shows the maximum enhancement by two orders of magnitude in comparison to the randomly distributed silver nanoparticles having similar size and shape as the PNG structure.« less

Preparation of Regular Specimens for Atom Probes

NASA Technical Reports Server (NTRS)

Kuhlman, Kim; Wishard, James

2003-01-01

A method of preparation of specimens of non-electropolishable materials for analysis by atom probes is being developed as a superior alternative to a prior method. In comparison with the prior method, the present method involves less processing time. Also, whereas the prior method yields irregularly shaped and sized specimens, the present developmental method offers the potential to prepare specimens of regular shape and size. The prior method is called the method of sharp shards because it involves crushing the material of interest and selecting microscopic sharp shards of the material for use as specimens. Each selected shard is oriented with its sharp tip facing away from the tip of a stainless-steel pin and is glued to the tip of the pin by use of silver epoxy. Then the shard is milled by use of a focused ion beam (FIB) to make the shard very thin (relative to its length) and to make its tip sharp enough for atom-probe analysis. The method of sharp shards is extremely time-consuming because the selection of shards must be performed with the help of a microscope, the shards must be positioned on the pins by use of micromanipulators, and the irregularity of size and shape necessitates many hours of FIB milling to sharpen each shard. In the present method, a flat slab of the material of interest (e.g., a polished sample of rock or a coated semiconductor wafer) is mounted in the sample holder of a dicing saw of the type conventionally used to cut individual integrated circuits out of the wafers on which they are fabricated in batches. A saw blade appropriate to the material of interest is selected. The depth of cut and the distance between successive parallel cuts is made such that what is left after the cuts is a series of thin, parallel ridges on a solid base. Then the workpiece is rotated 90 and the pattern of cuts is repeated, leaving behind a square array of square posts on the solid base. The posts can be made regular, long, and thin, as required for samples for atom-probe analysis. Because of their small volume and regularity, the amount of FIB-milling time can be much less than that of the method of sharp shards. Individual posts can be broken off for mounting in a manner similar to that of the method of sharp shards. Alternatively, the posts can be left intact on the base and the base can be cut to a small square (e.g., 3 by 3 mm) suitable for mounting in an atom probe of a type capable of accepting multiple-tip specimens. The advantage of multiple-tip specimens is the possibility of analyzing many tips without the time-consuming interchange of specimens.

Construction of a Virtual Scanning Electron Microscope (VSEM)

NASA Technical Reports Server (NTRS)

Fried, Glenn; Grosser, Benjamin

2004-01-01

The Imaging Technology Group (ITG) proposed to develop a Virtual SEM (VSEM) application and supporting materials as the first installed instrument in NASA s Virtual Laboratory Project. The instrument was to be a simulator modeled after an existing SEM, and was to mimic that real instrument as closely as possible. Virtual samples would be developed and provided along with the instrument, which would be written in Java.

Prediction of future hepatocellular carcinoma incidence in moderate to heavy alcohol drinkers with the FIB-4 liver fibrosis index.

PubMed

Suh, Beomseok; Yun, Jae Moon; Park, Sehhoon; Shin, Dong Wook; Lee, Tae Hoon; Yang, Hyung-Kook; Ahn, Eunmi; Lee, Hyejin; Park, Jin Ho; Cho, BeLong

2015-11-01

Although heavy alcoholics are at heightened risk for hepatocellular carcinoma (HCC), there are no guidelines that recommend HCC screening for heavy alcoholics. This study investigated FIB-4, a noninvasive and easily applicable liver fibrosis index, as a risk factor for HCC incidence among alcohol drinkers without viral hepatitis. This retrospective cohort study included 6661 generally healthy adults who were 30 years old or older, did not have chronic viral hepatitis, and visited Seoul National University Hospital for a general, routine health evaluation. The future HCC incidence was determined from National Health Insurance medical service claims data (median follow-up, 6.2 years). With adjustments for age, sex, body mass index, smoking, and alcohol, compared with subjects with FIB-4 values less 1.00, subjects with FIB-4 values greater than or equal to 1.75 and less than 2.10 and subjects with FIB-4 values greater than or equal to 2.10 had adjusted hazard ratios (aHRs) of 5.18 (95% confidence interval [CI], 1.12-24.00) and 13.63 (95% CI, 3.77-49.33), respectively, for HCC incidence. This was heightened in subjects who drank more 30 g of alcohol per day: the aHRs were 8.39 (95% CI, 1.28-54.87) and 16.58 (95% CI, 3.87-71.04), respectively. FIB-4 was shown to have a higher predictive value for HCC incidence than ultrasonographically detected liver cirrhosis (C-index, 0.665 vs 0.527; P = .044). High FIB-4 is a risk factor with a high predictive value for HCC incidence, especially among moderate to heavy alcoholics (>30 g/d). FIB-4 is a readily available and probably cost-effective clinical tool with potential value for identifying subpopulations of alcoholics at particularly high risk who would benefit from regular HCC screening. Further investigations are warranted to validate our results; nonetheless, our study suggests that FIB-4 may be useful in HCC screening among alcoholics. © 2015 American Cancer Society.

Comparison of the prognostic value of liver biopsy and FIB-4 index in patients coinfected with HIV and hepatitis C virus.

PubMed

Berenguer, Juan; Zamora, Francisco X; Aldámiz-Echevarría, Teresa; Von Wichmann, Miguel A; Crespo, Manel; López-Aldeguer, José; Carrero, Ana; Montes, Marisa; Quereda, Carmen; Téllez, María J; Galindo, María J; Sanz, José; Santos, Ignacio; Guardiola, Josep M; Barros, Carlos; Ortega, Enrique; Pulido, Federico; Rubio, Rafael; Mallolas, Josep; Tural, Cristina; Jusdado, Juan J; Pérez, Gloria; Díez, Cristina; Álvarez-Pellicer, Julio; Esteban, Herminia; Bellón, José M; González-García, Juan

2015-03-15

We compared the prognostic value of liver biopsy (LB) and FIB-4 index in patients with human immunodeficiency virus (HIV)/hepatitis C virus (HCV) coinfection. We studied patients from the Grupo de Estudio del SIDA 3603 study cohort, in whom fibrosis was evaluated at baseline using both LB (Metavir score) and FIB-4 index. We assessed overall death (OD) and liver-related events (LREs), defined as decompensation or hepatocellular carcinoma, whichever occurred first. We used receiver operating characteristic (ROC) curves to determine the ability of LB and FIB-4 to predict outcomes. We also assessed the association between advanced fibrosis-LB (F3 or greater) or FIB-4 (≥3.25)-and outcomes using multivariate Cox regression analysis. The study sample comprised 903 patients (328 with sustained virologic response [SVR]). Baseline fibrosis by LB was as follows: F0, n = 71; F1, n = 242; F2, n = 236; F3, n = 236; F4, n = 118. Fibrosis by FIB-4 was as follows: ≤1, n = 148; >1 to <3.25, n = 597; ≥3.25, n = 158. After a median follow-up of 62 months, there were 46 deaths and 71 LREs. The area under the ROC curves for OD/LREs was 0.648 and 0.742 for LB and FIB-4, respectively (P = .006). Similar results were found for patients without SVR and for OD and LREs separately. The adjusted hazard ratios of OD or LRE were 1.740 (95% confidence interval [CI], 1.119-2.7.06; P = .014) for advanced fibrosis assessed by LB and 3.896 (95% CI, 2.463-6.160; P < .001) assessed by FIB-4. FIB-4 outperformed LB as a predictor of OD and LRE. These findings are of relevance for clinical practice and research and call into question the role of LB as a gold standard for assessing prognosis in HIV/HCV coinfection. © The Author 2014. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Elemental distribution analysis of urinary crystals.

PubMed

Fazil Marickar, Y M; Lekshmi, P R; Varma, Luxmi; Koshy, Peter

2009-10-01

Various crystals are seen in human urine. Some of them, particularly calcium oxalate dihydrate, are seen normally. Pathological crystals indicate crystal formation initiating urinary stones. Unfortunately, many of the relevant crystals are not recognized in light microscopic analysis of the urinary deposit performed in most of the clinical laboratories. Many crystals are not clearly identifiable under the ordinary light microscopy. The objective of the present study was to perform scanning electron microscopic (SEM) assessment of various urinary deposits and confirm the identity by elemental distribution analysis (EDAX). 50 samples of urinary deposits were collected from urinary stone clinic. Deposits containing significant crystalluria (more than 10 per HPF) were collected under liquid paraffin in special containers and taken up for SEM studies. The deposited crystals were retrieved with appropriate Pasteur pipettes, and placed on micropore filter paper discs. The fluid was absorbed by thicker layers of filter paper underneath and discs were fixed to brass studs. They were then gold sputtered to 100 A and examined under SEM (Jeol JSM 35C microscope). When crystals were seen, their morphology was recorded by taking photographs at different angles. At appropriate magnification, EDAX probe was pointed to the crystals under study and the wave patterns analyzed. Components of the crystals were recognized by utilizing the data. All the samples analyzed contained significant number of crystals. All samples contained more than one type of crystal. The commonest crystals encountered included calcium oxalate monohydrate (whewellite 22%), calcium oxalate dihydrate (weddellite 32%), uric acid (10%), calcium phosphates, namely, apatite (4%), brushite (6%), struvite (6%) and octocalcium phosphate (2%). The morphological appearances of urinary crystals described were correlated with the wavelengths obtained through elemental distribution analysis. Various urinary crystals that are not reported under light microscopy could be recognized by SEM-EDAX combination. EDAX is a significant tool for recognizing unknown crystals not identified by ordinary light microscopy or SEM alone.

Use of fluorescence and scanning electron microscopy as tools in teaching biology

NASA Astrophysics Data System (ADS)

Ghosh, Nabarun; Silva, Jessica; Vazquez, Aracely; Das, A. B.; Smith, Don W.

2011-06-01

Recent nationwide surveys reveal significant decline in students' interest in Math and Sciences. The objective of this project was to inspire young minds in using various techniques involved in Sciences including Scanning Electron Microscopy. We used Scanning Electron Microscope in demonstrating various types of Biological samples. An SEM Tabletop model in the past decade has revolutionized the use of Scanning Electron Microscopes. Using SEM Tabletop model TM 1000 we studied biological specimens of fungal spores, pollen grains, diatoms, plant fibers, dust mites, insect parts and leaf surfaces. We also used fluorescence microscopy to view, to record and analyze various specimens with an Olympus BX40 microscope equipped with FITC and TRITC fluorescent filters, a mercury lamp source, DP-70 digital camera with Image Pro 6.0 software. Micrographs were captured using bright field microscopy, the fluoresceinisothiocyanate (FITC) filter, and the tetramethylrhodamine (TRITC) filter settings at 40X. A high pressure mercury lamp or UV source was used to excite the storage molecules or proteins which exhibited autofluorescence. We used fluorescent microscopy to confirm the localization of sugar beet viruses in plant organs by viewing the vascular bundles in the thin sections of the leaves and other tissues. We worked with the REU summer students on sample preparation and observation on various samples utilizing the SEM. Critical Point Drying (CPD) and metal coating with the sputter coater was followed before observing some cultured specimen and the samples that were soft in textures with high water content. SEM Top allowed investigating the detailed morphological features that can be used for classroom teaching. Undergraduate and graduate researchers studied biological samples of Arthropods, pollen grains and teeth collected from four species of snakes using SEM. This project inspired the research students to pursue their career in higher studies in science and 45% of the undergraduates participated in this project entered Graduate school.

Micro-bridge defects: characterization and root cause analysis

NASA Astrophysics Data System (ADS)

Santoro, Gaetano; Van den Heuvel, Dieter; Braggin, Jennifer; Rosslee, Craig; Leray, Philippe J.; Cheng, Shaunee; Jehoul, Christiane; Schreutelkamp, Robert; Hillel, Noam

2010-03-01

Defect review of advanced lithography processes is becoming more and more challenging as feature sizes decrease. Previous studies using a defect review SEM on immersion lithography generated wafers have resulted in a defect classification scheme which, among others, includes a category for micro-bridges. Micro-bridges are small connections between two adjacent lines in photo-resist and are considered device killing defects. Micro-bridge rates also tend to increase as feature sizes decrease, making them even more important for the next technology nodes. Especially because micro-bridge defects can originate from different root causes, the need to further refine and split up the classification of this type of defect into sub groups may become a necessity. This paper focuses on finding the correlation of the different types of micro-bridge defects to a particular root cause based on a full characterization and root cause analysis of this class of defects, by using advanced SEM review capabilities like high quality imaging in very low FOV, Multi Perspective SEM Imaging (MPSI), tilted column and rotated stage (Tilt&Rotation) imaging and Focused Ion Beam (FIB) cross sectioning. Immersion lithography material has been mainly used to generate the set of data presented in this work even though, in the last part of the results, some EUV lithography data will be presented as part of the continuing effort to extend the micro-bridge defect characterization to the EUV technology on 40 nm technology node and beyond.

Scanning electron microscope automatic defect classification of process induced defects

NASA Astrophysics Data System (ADS)

Wolfe, Scott; McGarvey, Steve

2017-03-01

With the integration of high speed Scanning Electron Microscope (SEM) based Automated Defect Redetection (ADR) in both high volume semiconductor manufacturing and Research and Development (R and D), the need for reliable SEM Automated Defect Classification (ADC) has grown tremendously in the past few years. In many high volume manufacturing facilities and R and D operations, defect inspection is performed on EBeam (EB), Bright Field (BF) or Dark Field (DF) defect inspection equipment. A comma separated value (CSV) file is created by both the patterned and non-patterned defect inspection tools. The defect inspection result file contains a list of the inspection anomalies detected during the inspection tools' examination of each structure, or the examination of an entire wafers surface for non-patterned applications. This file is imported into the Defect Review Scanning Electron Microscope (DRSEM). Following the defect inspection result file import, the DRSEM automatically moves the wafer to each defect coordinate and performs ADR. During ADR the DRSEM operates in a reference mode, capturing a SEM image at the exact position of the anomalies coordinates and capturing a SEM image of a reference location in the center of the wafer. A Defect reference image is created based on the Reference image minus the Defect image. The exact coordinates of the defect is calculated based on the calculated defect position and the anomalies stage coordinate calculated when the high magnification SEM defect image is captured. The captured SEM image is processed through either DRSEM ADC binning, exporting to a Yield Analysis System (YAS), or a combination of both. Process Engineers, Yield Analysis Engineers or Failure Analysis Engineers will manually review the captured images to insure that either the YAS defect binning is accurately classifying the defects or that the DRSEM defect binning is accurately classifying the defects. This paper is an exploration of the feasibility of the utilization of a Hitachi RS4000 Defect Review SEM to perform Automatic Defect Classification with the objective of the total automated classification accuracy being greater than human based defect classification binning when the defects do not require multiple process step knowledge for accurate classification. The implementation of DRSEM ADC has the potential to improve the response time between defect detection and defect classification. Faster defect classification will allow for rapid response to yield anomalies that will ultimately reduce the wafer and/or the die yield.

Signal-to-noise ratio enhancement on SEM images using a cubic spline interpolation with Savitzky-Golay filters and weighted least squares error.

PubMed

Kiani, M A; Sim, K S; Nia, M E; Tso, C P

2015-05-01

A new technique based on cubic spline interpolation with Savitzky-Golay smoothing using weighted least squares error filter is enhanced for scanning electron microscope (SEM) images. A diversity of sample images is captured and the performance is found to be better when compared with the moving average and the standard median filters, with respect to eliminating noise. This technique can be implemented efficiently on real-time SEM images, with all mandatory data for processing obtained from a single image. Noise in images, and particularly in SEM images, are undesirable. A new noise reduction technique, based on cubic spline interpolation with Savitzky-Golay and weighted least squares error method, is developed. We apply the combined technique to single image signal-to-noise ratio estimation and noise reduction for SEM imaging system. This autocorrelation-based technique requires image details to be correlated over a few pixels, whereas the noise is assumed to be uncorrelated from pixel to pixel. The noise component is derived from the difference between the image autocorrelation at zero offset, and the estimation of the corresponding original autocorrelation. In the few test cases involving different images, the efficiency of the developed noise reduction filter is proved to be significantly better than those obtained from the other methods. Noise can be reduced efficiently with appropriate choice of scan rate from real-time SEM images, without generating corruption or increasing scanning time. © 2015 The Authors Journal of Microscopy © 2015 Royal Microscopical Society.

The detection of metallic residues in skin stab wounds by means of SEM-EDS: A pilot study.

PubMed

Palazzo, Elisa; Amadasi, Alberto; Boracchi, Michele; Gentile, Guendalina; Maciocco, Francesca; Marchesi, Matteo; Zoja, Riccardo

2018-05-01

The morphological analysis of stab wounds may often not be accurate enough to link it with the type of wounding weapon, but a further evaluation may be performed with the search for metallic residues left during the contact between the instrument and the skin. In this study, Scanning Electron Microscopy-Energy Dispersive Spectroscopy (SEM-EDS) was applied to the study of cadaveric stab wounds performed with kitchen knives composed of iron, chromium and nickel, in order to verify the presence of metallic residues on the wound's edge. Two groups of 10 corpses were selected: group A, including victims of stab wounds and a control group B (died of natural causes). Samplings were performed on the lesions and in intact areas of group A, whereas in group B sampling were performed in non-exposed intact skin. Samples were then analysed with optical microscopy and SEM-EDS. In group A, optical microscopic analysis showed the presence of vital haemorrhagic infiltration, while SEM-EDS showed evidence of microscopic metal traces, isolated or clustered, consisting of iron, chromium and nickel. Moreover, in two cases organic residues of calcium and phosphate were detected, as a probable sign of bone lesion. Control samples (group A in intact areas and group B), were negative for the search of exogenous material to optical microscopy and SEM-EDS. The results show the utility and possible application of the SEM-EDS in theidentification of metallic residues from sharp weapons on the skin. Copyright © 2017 The Chartered Society of Forensic Sciences. Published by Elsevier B.V. All rights reserved.

Long-term monitoring of molecular markers can distinguish different seasonal patterns of fecal indicating bacteria sources.

PubMed

Riedel, Timothy E; Thulsiraj, Vanessa; Zimmer-Faust, Amity G; Dagit, Rosi; Krug, Jenna; Hanley, Kaitlyn T; Adamek, Krista; Ebentier, Darcy L; Torres, Robert; Cobian, Uriel; Peterson, Sophie; Jay, Jennifer A

2015-03-15

Elevated levels of fecal indicator bacteria (FIB) have been observed at Topanga Beach, CA, USA. To identify the FIB sources, a microbial source tracking study using a dog-, a gull- and two human-associated molecular markers was conducted at 10 sites over 21 months. Historical data suggest that episodic discharge from the lagoon at the mouth of Topanga Creek is the main source of bacteria to the beach. A decline in creek FIB/markers downstream from upper watershed development and a sharp increase in FIB/markers at the lagoon sites suggest sources are local to the lagoon. At the lagoon and beach, human markers are detected sporadically, dog marker peaks in abundance mid-winter, and gull marker is chronically elevated. Varied seasonal patterns of FIB and source markers were identified showing the importance of applying a suite of markers over long-term spatial and temporal sampling to identify a complex combination of sources of contamination. Copyright © 2014 Elsevier Ltd. All rights reserved.

Status of faecal pollution in ports: A basin-wide investigation in the Adriatic Sea.

PubMed

Luna, Gian Marco; Manini, Elena; Turk, Valentina; Tinta, Tinkara; D'Errico, Giuseppe; Baldrighi, Elisa; Baljak, Vanja; Buda, Donatella; Cabrini, Marina; Campanelli, Alessandra; Cenov, Arijana; Del Negro, Paola; Drakulović, Dragana; Fabbro, Cinzia; Glad, Marin; Grilec, Dolores; Grilli, Federica; Jokanović, Sandra; Jozić, Slaven; Kauzlarić, Vesna; Kraus, Romina; Marini, Mauro; Mikuš, Josip; Milandri, Stefania; Pećarević, Marijana; Perini, Laura; Quero, Grazia Marina; Šolić, Mladen; Lušić, Darija Vukić; Zoffoli, Silvia

2018-04-07

Ports are subject to a variety of anthropogenic impacts, and there is mounting evidence of faecal contamination through several routes. Yet, little is known about pollution in ports by faecal indicator bacteria (FIB). FIB spatio-temporal dynamics were assessed in 12 ports of the Adriatic Sea, a semi-enclosed basin under strong anthropogenic pressure, and their relationships with environmental variables were explored to gain insight into pollution sources. FIB were abundant in ports, often more so than in adjacent areas; their abundance patterns were related to salinity, oxygen, and nutrient levels. In addition, a molecular method, quantitative (q)PCR, was used to quantify FIB. qPCR enabled faster FIB determination and water quality monitoring that culture-based methods. These data provide robust baseline evidence of faecal contamination in ports and can be used to improve the management of routine port activities (dredging and ballast water exchange), having potential to spread pathogens in the sea. Copyright © 2018 Elsevier Ltd. All rights reserved.

Multi-scale image segmentation and numerical modeling in carbonate rocks

NASA Astrophysics Data System (ADS)

Alves, G. C.; Vanorio, T.

2016-12-01

Numerical methods based on computational simulations can be an important tool in estimating physical properties of rocks. These can complement experimental results, especially when time constraints and sample availability are a problem. However, computational models created at different scales can yield conflicting results with respect to the physical laboratory. This problem is exacerbated in carbonate rocks due to their heterogeneity at all scales. We developed a multi-scale approach performing segmentation of the rock images and numerical modeling across several scales, accounting for those heterogeneities. As a first step, we measured the porosity and the elastic properties of a group of carbonate samples with varying micrite content. Then, samples were imaged by Scanning Electron Microscope (SEM) as well as optical microscope at different magnifications. We applied three different image segmentation techniques to create numerical models from the SEM images and performed numerical simulations of the elastic wave-equation. Our results show that a multi-scale approach can efficiently account for micro-porosities in tight micrite-supported samples, yielding acoustic velocities comparable to those obtained experimentally. Nevertheless, in high-porosity samples characterized by larger grain/micrite ratio, results show that SEM scale images tend to overestimate velocities, mostly due to their inability to capture macro- and/or intragranular- porosity. This suggests that, for high-porosity carbonate samples, optical microscope images would be more suited for numerical simulations.

[Preparation of sodium alginate-nanohydroxyapatite composite material for bone repair and its biocompatibility].

PubMed

Wang, Yanmei; He, Jiacai; Li, Quanli; Shen, Jijia

2014-02-01

To prepare sodium alginate-nanohydroxyapatite composite material and to explore its feasibility as a bone repair material. Sodium alginate-nanohydroxyapatite composite material was prepared using chemical cross-linking and freeze-drying technology. The composite was characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM) and its porosity was measured by liquid displacement method. The fifth passage of bone marrow stromal stem cells (BMSCs) were incubated on the composite material and then growth was observed by inverted microscope and SEM. BMSCs were cultured with liquid extracts of the material, methyl thiazolyl tetrazolium (MTT) assay was used to calculate the relative growth rate (RGR) on 1, 3, 5 d and to evaluate the cytotoxicity. Fresh dog blood was added into the liquid extracts to conduct hemolysis test, the spectrophotometer was used to determine the optical density (OD) and to calculate the hemolysis rate. Sodium alginate-nanohydroxyapatite composite material displayed porosity, the porous pore rate was (88.6 +/- 4.5)%. BMSCs showed full stretching and vigorous growth under inverted microscope and SEM. BMSCs cultured with liquid extracts of the material had good activities. The toxicity of composite material was graded as 1. Hemolysis test results showed that the hemolysis rate of the composite material was 1.28%, thus meeting the requirement of medical biomaterials. The composite material fabricated in this study has high porosity and good biocompatibility.

Si amorphization by focused ion beam milling: Point defect model with dynamic BCA simulation and experimental validation.

PubMed

Huang, J; Loeffler, M; Muehle, U; Moeller, W; Mulders, J J L; Kwakman, L F Tz; Van Dorp, W F; Zschech, E

2018-01-01

A Ga focused ion beam (FIB) is often used in transmission electron microscopy (TEM) analysis sample preparation. In case of a crystalline Si sample, an amorphous near-surface layer is formed by the FIB process. In order to optimize the FIB recipe by minimizing the amorphization, it is important to predict the amorphous layer thickness from simulation. Molecular Dynamics (MD) simulation has been used to describe the amorphization, however, it is limited by computational power for a realistic FIB process simulation. On the other hand, Binary Collision Approximation (BCA) simulation is able and has been used to simulate ion-solid interaction process at a realistic scale. In this study, a Point Defect Density approach is introduced to a dynamic BCA simulation, considering dynamic ion-solid interactions. We used this method to predict the c-Si amorphization caused by FIB milling on Si. To validate the method, dedicated TEM studies are performed. It shows that the amorphous layer thickness predicted by the numerical simulation is consistent with the experimental data. In summary, the thickness of the near-surface Si amorphization layer caused by FIB milling can be well predicted using the Point Defect Density approach within the dynamic BCA model. Copyright © 2017 Elsevier B.V. All rights reserved.

Surface Modifications during a Catalytic Reaction: A Combined APT and FIB/SEM Analysis of Surface Segregation

DOE PAGES

Barroo, Cedric; Janvelyan, Nare; Zugic, Branko; ...

2016-07-25

To improve the understanding of catalytic processes, the surface structure and composition of the active materials need to be determined before and after reaction. Morphological changes may occur under reaction conditions and can dramatically influence the reactivity and/or selectivity of a catalyst. Goldbased catalysts with different architectures are currently being developed for selective oxidation reactions at low temperatures. Specifically, nanoporous Au (npAu) with a composition of Au 97-Ag 3 is obtained by dealloying a Ag 70-Au 30 bulk alloy. Recent studies highlight the efficiency of npAu catalysts for methanol oxidation using ozone to activate the catalysts before methanol oxidation. Inmore » this paper, we studied the morphological and compositional changes occurring at the surface of Au-based catalysts in certain conditions.« less

Characterisation of phases in nanostructured, multilayered titanium alloys by analytical and high-resolution electron microscopy.

PubMed

Czyrska-Filemonowicz, A; Buffat, P A

2009-01-01

Surface processing of a Ti-6Al-4V alloy led to a complex multilayered microstructure containing several phases of the Ni-Ti-P-Al-O system, which improves the mechanical and tribological surface properties. The microstructure, chemical and phase compositions of the hard layer formed on the surface were investigated by LM, XRD, SEM as well as analytical/high-resolution TEM, STEM, EDS, electron diffraction and FIB. Phase identification based on electron diffraction, HRTEM and EDS microanalysis revealed the presence of several binary and ternary phases in the system Ti-Ni-P, sometimes with partial substitution of Ti by Al. However some phases, mainly nanoparticles, still remain not identified satisfactorily. Electron microscopy techniques used for identification of phases present in surface multilayers and some practical limits to their routine application are reminded here.

Three dimensional electrochemical simulation of solid oxide fuel cell cathode based on microstructure reconstructed by marching cubes method

NASA Astrophysics Data System (ADS)

He, An; Gong, Jiaming; Shikazono, Naoki

2018-05-01

In the present study, a model is introduced to correlate the electrochemical performance of solid oxide fuel cell (SOFC) with the 3D microstructure reconstructed by focused ion beam scanning electron microscopy (FIB-SEM) in which the solid surface is modeled by the marching cubes (MC) method. Lattice Boltzmann method (LBM) is used to solve the governing equations. In order to maintain the geometries reconstructed by the MC method, local effective diffusivities and conductivities computed based on the MC geometries are applied in each grid, and partial bounce-back scheme is applied according to the boundary predicted by the MC method. From the tortuosity factor and overpotential calculation results, it is concluded that the MC geometry drastically improves the computational accuracy by giving more precise topology information.

Growth and FIB-SEM analyses of C60 microtubes vertically synthesized on porous alumina membranes

NASA Astrophysics Data System (ADS)

Miyazawa, Kun'ichi; Kuriyama, Ryota; Shimomura, Shuichi; Wakahara, Takatsugu; Tachibana, Masaru

2014-02-01

The vertical growth of C60 microtubes (C60MTs) on anodic aluminum oxide (AAO) membranes was investigated. The C60MT size dependence on isopropyl alcohol (IPA) injection rate, into C60-saturated toluene solutions through AAO membranes, was measured. A longitudinal section of the interface between a vertically grown C60MT (V-C60MT) and a membrane was prepared by focused ion beam processing, and observed with scanning electron microscopy. No cracking was observed along the interface, suggesting good bonding. V-C60MTs exhibited spiral growth. V-C60MT planar density, wall thickness and aspect ratio all decreased with increasing IPA injection rate. The relationships among length, inner and outer diameters of V-C60MTs were also investigated by varying IPA injection rate.

Glancing-incidence focussed ion beam milling: A coherent X-ray diffraction study of 3D nano-scale lattice strains and crystal defects

DOE PAGES

Hofmann, Felix; Harder, Ross J.; Liu, Wenjun; ...

2018-05-11

Here, this study presents a detailed examination of the lattice distortions introduced by glancing incidence Focussed Ion Beam (FIB) milling. Using non-destructive multi-reflection Bragg coherent X-ray diffraction we probe damage formation in an initially pristine gold micro-crystal following several stages of FIB milling. These experiments allow access to the full lattice strain tensor in the micro-crystal with ~25 nm 3D spatial resolution, enabling a nano-scale analysis of residual lattice strains and defects formed. Our results show that 30 keV glancing incidence milling produces fewer large defects than normal incidence milling at the same energy. However the resulting residual lattice strainsmore » have similar magnitude and extend up to ~50 nm into the sample. At the edges of the milled surface, where the ion-beam tails impact the sample at near-normal incidence, large dislocation loops with a range of Burgers vectors are formed. Further glancing incidence FIB polishing with 5 keV ion energy removes these dislocation loops and reduces the lattice strains caused by higher energy FIB milling. However, even at the lower ion energy, damage-induced lattice strains are present within a ~20 nm thick surface layer. These results highlight the need for careful consideration and management of FIB damage. They also show that low-energy FIB-milling is an effective tool for removing FIB-milling induced lattice strains. This is important for the preparation of micro-mechanical test specimens and strain microscopy samples.« less

Glancing-incidence focussed ion beam milling: A coherent X-ray diffraction study of 3D nano-scale lattice strains and crystal defects

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hofmann, Felix; Harder, Ross J.; Liu, Wenjun

Here, this study presents a detailed examination of the lattice distortions introduced by glancing incidence Focussed Ion Beam (FIB) milling. Using non-destructive multi-reflection Bragg coherent X-ray diffraction we probe damage formation in an initially pristine gold micro-crystal following several stages of FIB milling. These experiments allow access to the full lattice strain tensor in the micro-crystal with ~25 nm 3D spatial resolution, enabling a nano-scale analysis of residual lattice strains and defects formed. Our results show that 30 keV glancing incidence milling produces fewer large defects than normal incidence milling at the same energy. However the resulting residual lattice strainsmore » have similar magnitude and extend up to ~50 nm into the sample. At the edges of the milled surface, where the ion-beam tails impact the sample at near-normal incidence, large dislocation loops with a range of Burgers vectors are formed. Further glancing incidence FIB polishing with 5 keV ion energy removes these dislocation loops and reduces the lattice strains caused by higher energy FIB milling. However, even at the lower ion energy, damage-induced lattice strains are present within a ~20 nm thick surface layer. These results highlight the need for careful consideration and management of FIB damage. They also show that low-energy FIB-milling is an effective tool for removing FIB-milling induced lattice strains. This is important for the preparation of micro-mechanical test specimens and strain microscopy samples.« less

Elevated liver fibrosis index FIB-4 is not reliable for HCC risk stratification in predominantly non-Asian CHB patients

PubMed Central

Demir, Münevver; Grünewald, Friederike; Lang, Sonja; Schramm, Christoph; Bowe, Andrea; Mück, Vera; Kütting, Fabian; Goeser, Tobias; Steffen, Hans-Michael

2016-01-01

Abstract We aimed to validate the liver fibrosis index FIB-4 as a model for risk stratification of hepatocellular carcinoma development in predominantly non-Asian patients with chronic hepatitis B infection seen at a tertiary referral center in Germany. We retrospectively analyzed 373 adult patients with chronic hepatitis B infection. Patient demographics, hepatitis B markers, antiviral treatment, laboratory parameters, results from liver imaging and histology were recorded. Patients were divided into 2 groups according to their FIB-4 levels and their hazard ratios for developing hepatocellular carcinoma were analyzed adjusted for age, sex, body mass index, alcohol consumption, and antiviral medication. Median follow-up was 8.7 years (range 1–21.3 years), 93% of patients were of non-Asian origin, and 64% were male. Compared with patients with a low FIB-4 (<1.25) patients with FIB-4 ≥1.25 showed a hazard ratio for incidence of hepatocellular carcinoma of 3.03 (95% confidence interval (CI): 1.24–7.41) and an adjusted hazard ratio of 1.75 (95% CI: 0.64–4.74). Notably, 68% of patients with liver cirrhosis and 68% of those who developed HCC during observation had a low FIB-4 (<1.25). We could not confirm that a FIB-4 value ≥1.25 is a reliable clinical indicator for incidence of hepatocellular carcinoma in predominantly non-Asian patients with chronic hepatitis B. Further studies in geographically and ethnically diverse populations are needed to prove its utility as a predictive tool. PMID:27661015

Fibrinogen, Riboflavin, and UVA to Immobilize a Corneal Flap – Molecular Mechanisms

PubMed Central

Littlechild, Stacy L.; Zhang, Yuntao; Tomich, John M.; Conrad, Gary W.

2012-01-01

Purpose. Tissue glue containing fibrinogen (FIB) and riboflavin (RF), upon exposure to long wavelength ultraviolet light (UVA, 365 nM) has been proposed potentially to solve long-standing problems presented by corneal wound and epithelial ingrowth side-effects from laser-assisted in situ keratomileuis (LASIK). Data presented in a previous study demonstrated an ability of FIB + RF + UVA to adhere two stromal surfaces; however, to our knowledge no molecular mechanisms have been proposed to account for interactions occurring between corneal extracellular matrix (ECM) and tissue glue molecules. Here, we document several covalent and noncovalent interactions between these classes of macromolecules. Methods. SDS-PAGE and Western blot techniques were used to identify covalent interactions between tissue glue molecules and corneal ECM molecules in either the presence or absence of RF and UVA, in vitro and ex vivo. Surface plasmon resonance (SPR) was used to characterize noncovalent interactions, and obtain ka, kd, and KD binding affinity values. Results. SDS-PAGE and Western blot analyses indicated that covalent interactions occurred between neighboring FIB molecules, as well as between FIB and collagen type I (Coll-I) proteins (in vitro and ex vivo). These interactions occurred only in the presence of RF and UVA. SPR data demonstrated the ability of FIB to bind noncovalently to corneal stroma molecules, Coll-I, decorin, dermatan sulfate, and corneal basement membrane molecules, laminin and heparan sulfate – only in the presence of Zn2+. Conclusions. Covalent and (zinc-mediated) noncovalent mechanisms involving FIB and stromal ECM molecules contribute to the adhesion created by FIB + RF + UVA. PMID:22879413

Elevated liver fibrosis index FIB-4 is not reliable for HCC risk stratification in predominantly non-Asian CHB patients.

PubMed

Demir, Münevver; Grünewald, Friederike; Lang, Sonja; Schramm, Christoph; Bowe, Andrea; Mück, Vera; Kütting, Fabian; Goeser, Tobias; Steffen, Hans-Michael

2016-09-01

We aimed to validate the liver fibrosis index FIB-4 as a model for risk stratification of hepatocellular carcinoma development in predominantly non-Asian patients with chronic hepatitis B infection seen at a tertiary referral center in Germany.We retrospectively analyzed 373 adult patients with chronic hepatitis B infection. Patient demographics, hepatitis B markers, antiviral treatment, laboratory parameters, results from liver imaging and histology were recorded. Patients were divided into 2 groups according to their FIB-4 levels and their hazard ratios for developing hepatocellular carcinoma were analyzed adjusted for age, sex, body mass index, alcohol consumption, and antiviral medication.Median follow-up was 8.7 years (range 1-21.3 years), 93% of patients were of non-Asian origin, and 64% were male. Compared with patients with a low FIB-4 (<1.25) patients with FIB-4 ≥1.25 showed a hazard ratio for incidence of hepatocellular carcinoma of 3.03 (95% confidence interval (CI): 1.24-7.41) and an adjusted hazard ratio of 1.75 (95% CI: 0.64-4.74). Notably, 68% of patients with liver cirrhosis and 68% of those who developed HCC during observation had a low FIB-4 (<1.25).We could not confirm that a FIB-4 value ≥1.25 is a reliable clinical indicator for incidence of hepatocellular carcinoma in predominantly non-Asian patients with chronic hepatitis B. Further studies in geographically and ethnically diverse populations are needed to prove its utility as a predictive tool.

The monomeric, tetrameric, and fibrillar organization of Fib: the dynamic building block of the bacterial linear motor of Spiroplasma melliferum BC3.

PubMed

Cohen-Krausz, Sara; Cabahug, Pamela C; Trachtenberg, Shlomo

2011-07-08

Spiroplasmas belong to the class Mollicutes, representing the minimal, free-living, and self-replicating forms of life. Spiroplasmas are helical wall-less bacteria and the only ones known to swim by means of a linear motor (rather than the near-universal rotary bacterial motor). The linear motor follows the shortest path along the cell's helical membranal tube. The motor is composed of a flat monolayered ribbon of seven parallel fibrils and is believed to function in controlling cell helicity and motility through dynamic, coordinated, differential length changes in the fibrils. The latter cause local perturbations of helical symmetry, which are essential for net directional displacement in environments with a low Reynolds number. The underlying fibrils' core building block is a circular tetramer of the 59-kDa protein Fib. The fibrils' differential length changes are believed to be driven by molecular switching of Fib, leading consequently to axial ratio and length changes in tetrameric rings. Using cryo electron microscopy, diffractometry, single-particle analysis of isolated ribbons, and sequence analyses of Fib, we determined the overall molecular organization of the Fib monomer, tetramer, fibril, and linear motor of Spiroplasma melliferum BC3 that underlies cell geometry and motility. Fib appears to be a bidomained molecule, of which the N-terminal half is apparently a globular phosphorylase. By a combination of reversible rotation and diagonal shift of Fib monomers, the tetramer adopts either a cross-like nonhanded conformation or a ring-like handed conformation. The sense of Fib rotation may determine the handedness of the linear motor and, eventually, of the cell. A further change in the axial ratio of the ring-like tetramers controls fibril lengths and the consequent helical geometry. Analysis of tetramer quadrants from adjacent fibrils clearly demonstrates local differential fibril lengths. Copyright © 2011 Elsevier Ltd. All rights reserved.

AST-platelet ratio index, Forns index and FIB-4 in the prediction of significant fibrosis and cirrhosis in patients with chronic hepatitis C.

PubMed

Güzelbulut, Fatih; Çetınkaya, Züleyha Akkan; Sezıklı, Mesut; Yaşar, Bülent; Ozkara, Selvinaz; Övünç, Ayşe Oya Kurdaş

2011-06-01

The aim of this study was to evaluate the diagnostic accuracy of aspartate aminotransferase-platelet ratio index, the Forns index and FIB-4 for the assessment of hepatic fibrosis in chronic hepatitis C patients by comparison with liver biopsy. We retrospectively reviewed our computerized data of chronic hepatitis C patients who admitted to the Gastroenterology Clinic between 2004 and 2008. Treatment-naive chronic hepatitis C patients who had undergone liver biopsy and had laboratory test results allowing the calculation of aspartate aminotransferase-platelet ratio index, the Forns index and FIB-4 were included in this study. The degree of fibrosis was scored according to the METAVIR staging system. Significant fibrosis was defined as F2-4 and cirrhosis as F4. Aspartate aminotransferase-platelet ratio index, the Forns index and FIB-4 were calculated based on the original studies. Tests results were compared between groups F0-1 (no or mild fibrosis) versus F2-4 (significant fibrosis) and F03 (no cirrhosis) versus F4 (cirrhosis). One hundred and fifty patients with chronic hepatitis C were included in this study. The areas under the ROC curves of the Forns index, aspartate aminotransferase-platelet ratio index and FIB-4 to predict significant fibrosis were 0.795, 0.774 and 0.764, respectively. The area under the ROC curves of the Forns index, aspartate aminotransferase-platelet ratio index and FIB-4 to predict cirrhosis were 0.879, 0.839 and 0.874, respectively. The Forns index, aspartate aminotransferase-platelet ratio index and FIB-4 were accurate noninvasive blood tests to predict the presence or absence of significant fibrosis and cirrhosis in half of the chronic hepatitis C patients. The Forns index was slightly better than the aspartate aminotransferase-platelet ratio index and FIB-4 in the prediction of significant fibrosis and cirrhosis.

Predictive value of FIB-4 and APRI versus METAVIR on sustained virologic response in genotype 1 hepatitis C patients.

PubMed

Ferenci, Peter; Aires, Rodrigo; Beavers, Kimberly L; Curescu, Manuela; Abrão Ferreira, Paulo R; Gschwantler, Michael; Ion, Stefan; Larrey, Dominique; Maticic, Mojca; Puoti, Massimo; Schuller, János; Tornai, Istvan; Tusnádi, Anna; Messinger, Diethelm; Tatsch, Fernando; Horban, Andrzej

2014-01-01

Advanced liver fibrosis is a negative predictor of virologic response in genotype 1 chronic hepatitis C (CHC) patients. Biopsy, however, is invasive, costly, and carries some risk of complications. Using data from the prospective, international cohort study PROPHESYS, we assessed two alternative noninvasive measures of fibrosis, the FIB-4 and AST-to-platelet ratio index (APRI), to predict virologic response in CHC patients. CHC genotype 1, monoinfected, treatment-naive patients prescribed peginterferon alfa-2a (40 KD)/ribavirin in accordance with country-specific legal and regulatory requirements and who had baseline METAVIR, FIB-4, and APRI scores (N = 1,592) were included in this analysis. Patients were stratified according to the baseline METAVIR, FIB-4, or APRI score to assess virologic response [hepatitis C virus (HCV) RNA <50 IU/mL] by week 4 of treatment (rapid virologic response) and 24 weeks after untreated follow-up ]sustained virologic response (SVR)]. Baseline predictors of SVR were explored by multiple logistic regression, and the strength of the association between each fibrosis measure and SVR was evaluated. Both FIB-4 and APRI scores increased with increasing levels of biopsy-assessed fibrosis. The association between FIB-4 and SVR (p < 0.1 × 10(-30)) was stronger than that between METAVIR (p = 3.86 × 10(-13)) or APRI (p = 5.48 × 10(-6)) and SVR. Baseline factors significantly associated with SVR included male gender, lower HCV RNA, lower FIB-4 score, no steatosis, and higher alanine aminotransferase ratio. The FIB-4 index provides a valuable, noninvasive measure of fibrosis and can be used to predict virologic response in patients treated with peginterferon alfa-2a (40  KD)/ribavirin.

Value of Egy-Score in diagnosis of significant, advanced hepatic fibrosis and cirrhosis compared to aspartate aminotransferase-to-platelet ratio index, FIB-4 and Forns' index in chronic hepatitis C virus.

PubMed

Alboraie, Mohamed; Khairy, Marwa; Elsharkawy, Marwa; Asem, Noha; Elsharkawy, Aisha; Esmat, Gamal

2015-05-01

Serum markers and developed scores are of rising importance in non-invasive diagnosis of hepatic fibrosis. Aspartate aminotransferase-to-platelet ratio index (APRI), FIB-4 and Forns' index are validated scores used for diagnosis of liver fibrosis. The Egy-Score is a newly developed score for detection of hepatic fibrosis with promising results. We aimed to assess the accuracy of the Egy-Score in the diagnosis of significant fibrosis, advanced fibrosis and cirrhosis compared to APRI, FIB-4 and Forns' in chronic hepatitis C virus (HCV) patients. A retrospective study including 100 chronic hepatitis C naïve Egyptian patients was performed. Patients were classified according to stages of fibrosis into three groups: significant fibrosis (≥ F2), advanced fibrosis (≥ F3) and cirrhosis (F4). Egy-Score, APRI, FIB-4 and Forns' index were calculated. Regression analysis and receiver-operator curves were plotted to assess the sensitivity, specificity and predictive values for the significant scores with the best cut-off for diagnosis. An Egy-Score of 3.28 or more was superior to APRI, FIB-4 and Forns' index for detecting advanced fibrosis with a sensitivity of 91% and specificity of 78%. An Egy-Score of 3.67 or more was superior to APRI, FIB-4 and Forns' index for detecting cirrhosis with a sensitivity of 82% and specificity of 87%. Forns' index was superior to Egy-Score, FIB-4 and APRI for detecting significant fibrosis. The Egy-Score is a promising, accurate, easily calculated, cost-effective score in the prediction of hepatic fibrosis in chronic HCV patients with superiority over APRI, FIB-4 and Forns' index in advanced hepatic fibrosis and cirrhosis. © 2014 The Japan Society of Hepatology.

Helium Ion Microscope: A New Tool for Sub-nanometer Imaging of Soft Materials

NASA Astrophysics Data System (ADS)

Shutthanandan, V.; Arey, B.; Smallwood, C. R.; Evans, J. E.

2017-12-01

High-resolution inspection of surface details is needed in many biological and environmental researches to understand the Soil organic material (SOM)-mineral interactions along with identifying microbial communities and their interactions. SOM shares many imaging characteristics with biological samples and getting true surface details from these materials are challenging since they consist of low atomic number materials. FE-SEM imaging is the main imagining technique used to image these materials in the past. These SEM images often show loss of resolution and increase noise due to beam damage and charging issues. Newly developed Helium Ion Microscope (HIM), on the other hand can overcome these difficulties and give very fine details. HIM is very similar to scanning electron microscopy (SEM) but instead of using electrons as a probe beam, HIM uses helium ions with energy ranges from 5 to 40 keV. HIM offers a series of advantages compared to SEM such as nanometer and sub-nanometer image resolutions (about 0.35 nm), detailed surface topography, high surface sensitivity, low Z material imaging (especially for polymers and biological samples), high image contrast, and large depth of field. In addition, HIM also has the ability to image insulating materials without any conductive coatings so that surface details are not modified. In this presentation, several scientific applications across biology and geochemistry will be presented to highlight the effectiveness of this powerful microscope. Acknowledgements: Research was performed using the Environmental Molecular Sciences Laboratory (EMSL), a national scientific user facility sponsored by the Department of Energy's Office of Biological and Environmental Research and located at PNNL. Work was supported by DOE-BER Mesoscale to Molecules Bioimaging Project FWP# 66382.

Practical application of HgI2 detectors to a space-flight scanning electron microscope

NASA Technical Reports Server (NTRS)

Bradley, J. G.; Conley, J. M.; Albee, A. L.; Iwanczyk, J. S.; Dabrowski, A. J.

1989-01-01

Mercuric iodide X-ray detectors have been undergoing tests in a prototype scanning electron microscope system being developed for unmanned space flight. The detector program addresses the issues of geometric configuration in the SEM, compact packaging that includes separate thermoelectric coolers for the detector and FET, X-ray transparent hermetic encapsulation and electrical contacts, and a clean vacuum environment.

A simplified focusing and astigmatism correction method for a scanning electron microscope

NASA Astrophysics Data System (ADS)

Lu, Yihua; Zhang, Xianmin; Li, Hai

2018-01-01

Defocus and astigmatism can lead to blurred images and poor resolution. This paper presents a simplified method for focusing and astigmatism correction of a scanning electron microscope (SEM). The method consists of two steps. In the first step, the fast Fourier transform (FFT) of the SEM image is performed and the FFT is subsequently processed with a threshold to achieve a suitable result. In the second step, the threshold FFT is used for ellipse fitting to determine the presence of defocus and astigmatism. The proposed method clearly provides the relationships between the defocus, the astigmatism and the direction of stretching of the FFT, and it can determine the astigmatism in a single image. Experimental studies are conducted to demonstrate the validity of the proposed method.

Sparsity-Based Super Resolution for SEM Images.

PubMed

Tsiper, Shahar; Dicker, Or; Kaizerman, Idan; Zohar, Zeev; Segev, Mordechai; Eldar, Yonina C

2017-09-13

The scanning electron microscope (SEM) is an electron microscope that produces an image of a sample by scanning it with a focused beam of electrons. The electrons interact with the atoms in the sample, which emit secondary electrons that contain information about the surface topography and composition. The sample is scanned by the electron beam point by point, until an image of the surface is formed. Since its invention in 1942, the capabilities of SEMs have become paramount in the discovery and understanding of the nanometer world, and today it is extensively used for both research and in industry. In principle, SEMs can achieve resolution better than one nanometer. However, for many applications, working at subnanometer resolution implies an exceedingly large number of scanning points. For exactly this reason, the SEM diagnostics of microelectronic chips is performed either at high resolution (HR) over a small area or at low resolution (LR) while capturing a larger portion of the chip. Here, we employ sparse coding and dictionary learning to algorithmically enhance low-resolution SEM images of microelectronic chips-up to the level of the HR images acquired by slow SEM scans, while considerably reducing the noise. Our methodology consists of two steps: an offline stage of learning a joint dictionary from a sequence of LR and HR images of the same region in the chip, followed by a fast-online super-resolution step where the resolution of a new LR image is enhanced. We provide several examples with typical chips used in the microelectronics industry, as well as a statistical study on arbitrary images with characteristic structural features. Conceptually, our method works well when the images have similar characteristics, as microelectronics chips do. This work demonstrates that employing sparsity concepts can greatly improve the performance of SEM, thereby considerably increasing the scanning throughput without compromising on analysis quality and resolution.

Metabolic and Epigenetic Interactions Regulate Vascular Phenotypic Change and Maintenance in Pulmonary Hypertension

DTIC Science & Technology

2016-10-01

Krebs cycle through the generation of alpha-ketoglutarate. However, increased oxidative stress affected oxygen consumption rates at the Complex I...machinery and respiration in PH-Fibs. The difference in endogenous respiration, (i.e., oxygen consumption ) was not statistically different compared...driven through complex I. We found a roughly17% drop in oxygen consumption in PH-Fibs versus Co-Fibs (Figure 3C), which corresponded to the down

A FIB/TEM Study of a Complex Wark-Lovering Rim on a Vigarano CAI

NASA Technical Reports Server (NTRS)

Keller, L. P.; Needham, A. W.; Messenger, S.

2013-01-01

Wark-Lovering (WL) rims are thin multilayered mineral sequences that surround most Ca, Al-rich inclusions (CAIs). Several processes have been proposed for WL rim formation, including condensation, flash-heating or reaction with a nebular reservoir, or combinations of these [e.g. 1-7], but no consensus exists. Our previous coordinated transmission electron microscope (TEM) and NanoSIMS O isotopic measurements showed that a WL rim experienced flash heating events in a nebular environment with planetary O isotopic composition, distinct from the (16)O-rich formation environment [6]. Our efforts have focused on CAIs from the CV(sub red) chondrites, especially Vigarano, because these have escaped much of the parent body alteration effects that are common in CAIs from CV(sub ox) group.

Mechanism of Corrosion by Naphthenic Acids and Organosulfur Compounds at High Temperatures

NASA Astrophysics Data System (ADS)

Jin, Peng

Due to the law of supply and demand, the last decade has witnessed a skyrocketing in the price of light sweet crude oil. Therefore, refineries are increasingly interested in "opportunity crudes", characterized by their discounted price and relative ease of procurement. However, the attractive economics of opportunity crudes come with the disadvantage of high acid/organosulfur compound content, which could lead to corrosion and even failure of facilities in refineries. However, it is generally accepted that organosulfur compounds may form protective iron sulfide layers on the metal surface and decrease the corrosion rate. Therefore, it is necessary to investigate the corrosive property of crudes at high temperatures, the mechanism of corrosion by acids (naphthenic acids) in the presence of organosulfur compounds, and methods to mitigate its corrosive effect. In 2004, an industrial project was initiated at the Institute for Corrosion and Multiphase Technology to investigate the corrosion by naphthenic acids and organosulfur compounds. In this project, for each experiment there were two experimentation phases: pretreatment and challenge. In the first pretreatment phase, a stirred autoclave was filled with a real crude oil fraction or model oil of different acidity and organosulfur compound concentration. Then, the stirred autoclave was heated to high temperatures to examine the corrosivity of the oil to different materials (specimens made from CS and 5% Cr containing steel were used). During the pretreatment, corrosion product layers were formed on the metal surface. In the second challenge phase, the steel specimens pretreated in the first phase were inserted into a rotating cylinder autoclave, called High Velocity Rig (HVR). The HVR was fed with a high-temperature oil solution of naphthenic acids to attack the iron sulfide layers. Based on the difference of specimen weight loss between the two steps, the net corrosion rate could be calculated and the protectiveness of corrosion product layer against naphthenic acid corrosion could be assessed. Routinely, the layers generated in pretreatment and challenge phases were investigated with SEM/EDS (Scanning Electron Microscopy/Energy Dispersive Spectroscopy). Selectively, some thin layers formed in the first or second phase were analyzed with FIB-TEM (Focused Ion Beam - Transmission Electron Microscopy). FIB-TEM analysis revealed that there was an iron oxide layer beneath the iron sulfide layer. Experimental results showed that the iron oxide layer was closely related to the layer protectiveness against naphthenic acid corrosion and its formation was due to the presence of naphthenic acids in the fluid. Finally, a new mechanism of naphthenic acid/organosulfur compound corrosion was proposed based on properties of crudes, results of corrosion experimentation, and microscopic analysis of developed surface layers.

Autoregressive linear least square single scanning electron microscope image signal-to-noise ratio estimation.

PubMed

Sim, Kok Swee; NorHisham, Syafiq

2016-11-01

A technique based on linear Least Squares Regression (LSR) model is applied to estimate signal-to-noise ratio (SNR) of scanning electron microscope (SEM) images. In order to test the accuracy of this technique on SNR estimation, a number of SEM images are initially corrupted with white noise. The autocorrelation function (ACF) of the original and the corrupted SEM images are formed to serve as the reference point to estimate the SNR value of the corrupted image. The LSR technique is then compared with the previous three existing techniques known as nearest neighbourhood, first-order interpolation, and the combination of both nearest neighborhood and first-order interpolation. The actual and the estimated SNR values of all these techniques are then calculated for comparison purpose. It is shown that the LSR technique is able to attain the highest accuracy compared to the other three existing techniques as the absolute difference between the actual and the estimated SNR value is relatively small. SCANNING 38:771-782, 2016. © 2016 Wiley Periodicals, Inc. © Wiley Periodicals, Inc.

Degradation of metallic materials studied by correlative tomography

NASA Astrophysics Data System (ADS)

Burnett, T. L.; Holroyd, N. J. H.; Lewandowski, J. J.; Ogurreck, M.; Rau, C.; Kelley, R.; Pickering, E. J.; Daly, M.; Sherry, A. H.; Pawar, S.; Slater, T. J. A.; Withers, P. J.

2017-07-01

There are a huge array of characterization techniques available today and increasingly powerful computing resources allowing for the effective analysis and modelling of large datasets. However, each experimental and modelling tool only spans limited time and length scales. Correlative tomography can be thought of as the extension of correlative microscopy into three dimensions connecting different techniques, each providing different types of information, or covering different time or length scales. Here the focus is on the linking of time lapse X-ray computed tomography (CT) and serial section electron tomography using the focussed ion beam (FIB)-scanning electron microscope to study the degradation of metals. Correlative tomography can provide new levels of detail by delivering a multiscale 3D picture of key regions of interest. Specifically, the Xe+ Plasma FIB is used as an enabling tool for large-volume high-resolution serial sectioning of materials, and also as a tool for preparation of microscale test samples and samples for nanoscale X-ray CT imaging. The exemplars presented illustrate general aspects relating to correlative workflows, as well as to the time-lapse characterisation of metal microstructures during various failure mechanisms, including ductile fracture of steel and the corrosion of aluminium and magnesium alloys. Correlative tomography is already providing significant insights into materials behaviour, linking together information from different instruments across different scales. Multiscale and multifaceted work flows will become increasingly routine, providing a feed into multiscale materials models as well as illuminating other areas, particularly where hierarchical structures are of interest.

Impact of FIB-4 index on hepatocellular carcinoma incidence during nucleos(t)ide analogue therapy in patients with chronic hepatitis B: An analysis using time-dependent receiver operating characteristic.

PubMed

Tada, Toshifumi; Kumada, Takashi; Toyoda, Hidenori; Tsuji, Kunihiko; Hiraoka, Atsushi; Tanaka, Junko

2017-02-01

Nucleos(t)ide analogue (NA) therapy has been reported to reduce the risk of hepatocellular carcinoma (HCC) development in patients with chronic hepatitis B (CHB). However, even during NA therapy, development of HCC has been observed in patients with CHB. Therefore, we clarified the predictive power of clinical factors for HCC incidence using receiver operating characteristic (ROC) analysis that takes time dependence into account. A total of 539 patients with CHB treated with NAs were enrolled. Univariate, multivariate, and time-dependent ROC curves for clinical factors associated with the development of HCC were analyzed. Eighty-one patients developed HCC during the follow-up period (median duration, 5.9 years). α-fetoprotein (AFP) and FIB-4 index at 24 weeks from the initiation of treatment and sex were significantly associated with HCC incidence according to the log-rank test. Cox proportional hazards models including the covariates of sex, hepatitis B genotype, basal core promoter mutations, AFP at 24 weeks, and FIB-4 index at 24 weeks showed that FIB-4 index >2.65 (HR, 5.03; 95% CI, 3.06-8.26; P < 0.001) and male sex were independently associated with HCC incidence. In addition, time-dependent ROC analysis showed that compared with AFP at 24 weeks, FIB-4 index at 24 weeks had higher predictive power for HCC incidence throughout the follow-up period. Elevated FIB-4 index at 24 weeks in patients with CHB receiving NA therapy is a risk factor for developing HCC. The FIB-4 index is an excellent predictor of HCC development. © 2016 Journal of Gastroenterology and Hepatology Foundation and John Wiley & Sons Australia, Ltd.

Evaluation of APRI and FIB-4 scoring systems for non-invasive assessment of hepatic fibrosis in chronic hepatitis B patients.

PubMed

Kim, W Ray; Berg, Thomas; Asselah, Tarik; Flisiak, Robert; Fung, Scott; Gordon, Stuart C; Janssen, Harry L A; Lampertico, Pietro; Lau, Daryl; Bornstein, Jeffrey D; Schall, Raul E Aguilar; Dinh, Phillip; Yee, Leland J; Martins, Eduardo B; Lim, Seng Gee; Loomba, Rohit; Petersen, Jörg; Buti, Maria; Marcellin, Patrick

2016-04-01

While the gold standard in the assessment of liver fibrosis remains liver biopsy, non-invasive methods have been increasingly used for chronic hepatitis B (CHB). This study aimed to evaluate the performance of two commonly used non-invasive scoring systems (aspartate aminotransferase-to-platelet ratio index (APRI) and fibrosis index based on four factors (FIB-4)) to predict fibrosis stage in CHB patients. Demographic, histologic and clinical laboratory data from two trials investigating tenofovir disoproxil fumarate in CHB were analyzed. Predicted fibrosis stage, based on established scales and cut-off values for APRI and FIB-4 scores, was compared with Ishak scores obtained from liver biopsy at baseline and at 240 week follow-up. In the 575 patients with a baseline liver biopsy, APRI and FIB-4 scores correlated with Ishak stage (p<0.01); however extensive overlap in the distribution of both scores across Ishak stages prevented accurate determination of fibrosis. The majority (81-89%) of patients with advanced fibrosis or cirrhosis were missed by the scores. Similarly, 71% patients without fibrosis were misclassified as having clinically significant fibrosis. APRI and FIB-4 scores at week 240 tended to be low and underestimate fibrosis stage in the patients with liver biopsies after 240 weeks of therapy. APRI or FIB-4 reduction did not correlate with fibrosis regression after 240 weeks of antiviral therapy. APRI and FIB-4 scores are not suitable for use in clinical practice in CHB patients for assessment of hepatic fibrosis according to Ishak stage, especially in gauging improvements in liver fibrosis following therapy. Copyright © 2015 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.

Clinical significance of the FIB-4 index for non-B non-C hepatocellular carcinoma treated with surgical resection.

PubMed

Nishikawa, Hiroki; Osaki, Yukio; Komekado, Hideyuki; Sakamoto, Azusa; Saito, Sumio; Nishijima, Norihiro; Nasu, Akihiro; Arimoto, Akira; Kita, Ryuichi; Kimura, Toru

2015-01-01

The aims of the present study were to examine the relationship between the preoperative FIB-4 index and background liver fibrosis in non-tumor parts obtained from surgical specimens and to investigate whether the FIB-4 index can be a useful predictor for non-B non-C hepatocellular carcinoma (NBNC-HCC) patients treated with surgical resection (SR). A total of 118 patients with NBNC-HCC treated with SR with curative intent were analyzed. Receiver operating characteristic (ROC) curve analysis was performed for calculating the area under the ROC (AUROC) for the FIB-4 index, aspartate aminotransferase (AST) to platelet ratio index, AST to alanine aminotransferase ratio, serum albumin, total bilirubin and platelet count for cirrhosis. We also examined predictors linked to overall survival (OS) and recurrence-free survival (RFS) after SR. The mean patient age was 68.9±9.0 years (93 males and 25 females) with a median observation period of 3.2 years. In extracted surgical specimens, background liver cirrhosis (F4) was observed in 39 patients (33.1%). The mean maximum tumor size was 5.7±3.2 cm. The mean body mass index was 24.3±3.9 kg/m2. The FIB-4 index yielded the highest AUROC for cirrhosis with a level of 0.887 at an optimal cut-off value of 2.97 (sensitivity, 92.3; specificity, 69.6%). In the multivariate analysis, serum α-fetoprotein >40 ng/ml (P=0.026) was the only significant independent predictor linked to OS, while tumor number (P=0.002) and FIB-4 index >2.97 (P=0.044) were significant factors linked to RFS. In conclusion, preoperative FIB-4 index can be a useful predictor for NBNC-HCC patients who undergo SR.

Impact of age on the diagnostic performances and cut-offs of APRI and FIB-4 for significant fibrosis and cirrhosis in chronic hepatitis B.

PubMed

Li, Qiang; Lu, Chuan; Li, Weixia; Huang, Yuxian; Chen, Liang

2017-07-11

Assessing the diagnostic performances of APRI and FIB-4 using age as a categorical marker. 822 chronic hepatitis B (CHB) patients were included. Using METAVIR scoring system as a reference, the performances of APRI and FIB-4 were compared between patients aged≥30 and patients aged<30 years. The APRI AUROC in patients aged<30 years was lower than that in patients aged≥30 years for significant fibrosis (0.61 vs 0.70, p<0.001) and cirrhosis (0.64 vs 0.78, p<0.001). The FIB-4 AUROC in patients aged<30 years was lower than that in patients aged≥30 years for significant fibrosis (0.57 vs 0.65, p<0.001) and cirrhosis (0.63 vs 0.72, p<0.001). Using specificity≥90%, the APRI cut-off in patients aged<30 years was lower than patients aged≥30 years for significant fibrosis (1.0 vs 1.2) and cirrhosis (1.2 vs 1.5). Using sensitivity≥90%, the APRI cut-off in patients aged<30 years was also lower than patients aged≥30 years for significant fibrosis (0.2 vs 0.4) and cirrhosis (0.3 vs 0.5). Using specificity≥90%, the FIB-4 cut-off in patients aged<30 years was lower than that in patients aged≥30 years for significant fibrosis (1.2 vs 2.1) and cirrhosis (1.4 vs 2.6). Using sensitivity≥90%, the FIB-4 cut-off in patients aged<30 years was also lower than that in patients aged≥30 years for significant fibrosis (0.5 vs 0.8) and cirrhosis (0.8 vs 1.2). Evaluation of the diagnostic performances of APRI and FIB-4 should take age into consideration.

High FIB-4 index as an independent risk factor of prevalent chronic kidney disease in patients with nonalcoholic fatty liver disease.

PubMed

Xu, Huang-Wei; Hsu, Yung-Chien; Chang, Chia-Hao; Wei, Kuo-Liang; Lin, Chun-Liang

2016-03-01

Growing evidence suggests that non-alcoholic fatty liver disease (NAFLD) is linked to an increased risk for chronic kidney disease (CKD); liver fibrosis with biopsy-proven NAFLD has also been shown to associate with an increased risk of CKD. This study compares the diagnostic performance of simple noninvasive tests in identifying prevalent CKD among individuals with ultrasonography-diagnosed NAFLD. A total of 755 with ultrasonography-diagnosed NAFLD were included. Estimated glomerular filtration rate and noninvasive markers for hepatic fibrosis: aspartate transaminase to alanine transaminase ratio (AAR), aspartate transaminase to platelet ratio index (APRI), FIB-4 score, NAFLD fibrosis score (NFS) and BARD score were assessed. Binary logistic regression to generate a propensity score and receiver operating characteristic curves were developed for each of the noninvasive markers for predicting CKD, and the area under the receiver operating characteristic curve was greatest for FIB-4 score (0.750), followed by NFS (0.710), AAR (0.594), APRI (0.587), and BARD score (0.561). A cut-off value of 1.100 for FIB-4 score gave a sensitivity of 68.85% and a specificity of 71.07% for predicting CKD. The positive predictive value and negative predictive value were 37.50 and 90.05%, respectively. In multiple logistic regression analysis, only FIB-4 score ≧1.100 (OR 2.660, 95% CI 1.201-5.889; p = .016), older age, higher diastolic blood pressure and higher uric acid were independent predictors of CKD. High noninvasive fibrosis score is associated with an increased risk of prevalent CKD; the FIB-4 is the better predictor. With a cut-off value of 1.100 for FIB-4, it is useful in excluding the presence of CKD in patients with NAFLD.

Fibrin-Genipin Adhesive Hydrogel for Annulus Fibrosus Repair: Performance Evaluation with Large Animal Organ Culture, In Situ Biomechanics, and In Vivo Degradation Tests

PubMed Central

Likhitpanichkul, M.; Dreischarf, M.; Illien-Junger, S.; Walter, B. A.; Nukaga, T.; Long, R. G; Sakai, D.; Hecht, A. C.; Iatridis, J. C.

2015-01-01

Annulus fibrosus (AF) defects from annular tears, herniation, and discectomy procedures are associated with painful conditions and accelerated intervertebral disc (IVD) degeneration. Currently, no effective treatments exist to repair AF damage, restore IVD biomechanics and promote tissue regeneration. An injectable fibrin-genipin adhesive hydrogel (Fib-Gen) was evaluated for its performance repairing large AF defects in a bovine caudal IVD model using ex vivo organ culture and biomechanical testing of motion segments, and for its in vivo longevity and biocompatibility in a rat model by subcutaneous implantation. Fib-Gen sealed AF defects, prevented IVD height loss, and remained well-integrated with native AF tissue following approximately 14,000 cycles of compression in 6-day organ culture experiments. Fib-Gen repair also retained high viability of native AF cells near the repair site, reduced nitric oxide released to the media, and showed evidence of AF cell migration into the gel. Biomechanically, Fib-Gen fully restored compressive stiffness to intact levels validating organ culture findings. However, only partial restoration of tensile and torsional stiffness was obtained, suggesting opportunities to enhance this formulation. Subcutaneous implantation results, when compared with the literature, suggested Fib-Gen exhibited similar biocompatibility behaviour to fibrin alone but degraded much more slowly. We conclude that injectable Fib-Gen successfully sealed large AF defects, promoted functional restoration with improved motion segment biomechanics, and served as a biocompatible adhesive biomaterial that had greatly enhanced in vivo longevity compared to fibrin. Fib-Gen offers promise for AF repairs that may prevent painful conditions and accelerated degeneration of the IVD, and warrants further material development and evaluation. PMID:25036053

Fibrin-genipin adhesive hydrogel for annulus fibrosus repair: performance evaluation with large animal organ culture, in situ biomechanics, and in vivo degradation tests.

PubMed

Likhitpanichkul, M; Dreischarf, M; Illien-Junger, S; Walter, B A; Nukaga, T; Long, R G; Sakai, D; Hecht, A C; Iatridis, J C

2014-07-18

Annulus fibrosus (AF) defects from annular tears, herniation, and discectomy procedures are associated with painful conditions and accelerated intervertebral disc (IVD) degeneration. Currently, no effective treatments exist to repair AF damage, restore IVD biomechanics and promote tissue regeneration. An injectable fibrin-genipin adhesive hydrogel (Fib-Gen) was evaluated for its performance repairing large AF defects in a bovine caudal IVD model using ex vivo organ culture and biomechanical testing of motion segments, and for its in vivo longevity and biocompatibility in a rat model by subcutaneous implantation. Fib-Gen sealed AF defects, prevented IVD height loss, and remained well-integrated with native AF tissue following approximately 14,000 cycles of compression in 6-day organ culture experiments. Fib-Gen repair also retained high viability of native AF cells near the repair site, reduced nitric oxide released to the media, and showed evidence of AF cell migration into the gel. Biomechanically, Fib-Gen fully restored compressive stiffness to intact levels validating organ culture findings. However, only partial restoration of tensile and torsional stiffness was obtained, suggesting opportunities to enhance this formulation. Subcutaneous implantation results, when compared with the literature, suggested Fib-Gen exhibited similar biocompatibility behaviour to fibrin alone but degraded much more slowly. We conclude that injectable Fib-Gen successfully sealed large AF defects, promoted functional restoration with improved motion segment biomechanics, and served as a biocompatible adhesive biomaterial that had greatly enhanced in vivo longevity compared to fibrin. Fib-Gen offers promise for AF repairs that may prevent painful conditions and accelerated degeneration of the IVD, and warrants further material development and evaluation.

Modeling Fecal Indicator Bacteria Like Salt in Newport Bay

NASA Astrophysics Data System (ADS)

Ciglar, A. M.; Rippy, M.; Grant, S. B.

2015-12-01

Newport Bay is a harbor and estuary located in Orange County, CA that provides many water sports and recreational activities for millions of southern California residents and tourists. The aim of this study is to quickly assess exceedances of FIB in the Newport Bay which pose a health risk to recreational users. The ability to quickly assess water quality is made possible with an advection-diffusion mass transport model that uses easily measurable parameters such as volumetric flow rate from tributaries. Current FIB assessment methods for Newport Bay take a minimum of 24 hours to evaluate health risk by either culturing for FIB or running a more complex fluid dynamics model. By this time the FIB may have already reached the ocean outlet thus no longer posing a risk in the bay or recreationists may have already come in close contact with contaminated waters. The advection-diffusion model can process and disseminate health risk information within a few hours of flow rate measurements, minimizing time between an FIB exceedance and public awareness about the event. Data used to calibrate and validate the model was collected from January 2006 through February 2007. Salinity data was used for calibration and FIB data was used for validation. Both steady-state and transient conditions were assessed to determine if dry weather patterns can be simplified to the steady-state condition.

Fabrication of single Ga-doped ZnS nanowires as high-gain photosensors by focused ion beam deposition

NASA Astrophysics Data System (ADS)

Yen, Shih-Hsiang; Hung, Yu-Chen; Yeh, Ping-Hung; Su, Ya-Wen; Wang, Chiu-Yen

2017-09-01

ZnS nanowires were synthesized via a vapor-liquid-solid mechanism and then fabricated into a single-nanowire field-effect transistor by focused ion beam (FIB) deposition. The field-effect electrical properties of the FIB-fabricated ZnS nanowire device, namely conductivity, mobility and hole concentration, were 9.13 Ω-1 cm-1, 13.14 cm2 V-1 s-1and 4.27 × 1018 cm-3, respectively. The photoresponse properties of the ZnS nanowires were studied and the current responsivity, current gain, response time and recovery time were 4.97 × 106 A W-1, 2.43 × 107, 9 s and 24 s, respectively. Temperature-dependent I-V measurements were used to analyze the interfacial barrier height between ZnS and the FIB-deposited Pt electrode. The results show that the interfacial barrier height is as low as 40 meV. The energy-dispersive spectrometer elemental line scan shows the influence of Ga ions on the ZnS nanowire surface on the FIB-deposited Pt contact electrodes. The results of temperature-dependent I-V measurements and the elemental line scan indicate that Ga ions were doped into the ZnS nanowire, reducing the barrier height between the FIB-deposited Pt electrodes and the single ZnS nanowire. The small barrier height results in the FIB-fabricated ZnS nanowire device acting as a high-gain photosensor.

Bacteriophages as indicators of faecal pollution and enteric ...

EPA Pesticide Factsheets

Bacteriophages are an attractive alternative to fecal indicator bacteria (FIB), particularly as surrogates of enteric virus fate and transport due to their closer morphological and biological properties compared to FIB. Based on a meta-analysis of published data, we summarize concentrations of coliphages (F+ and somatic), Bacteroides spp. and enterococci bacteriophages (phages) in human waste, non-human waste, fresh and marine waters as well as removal through wastewater treatment processes. We also provide comparisons with FIB and enteric viruses whenever possible. Lastly, we examine fate and transport characteristics in the environment and provide an overview of the methods available for detection and enumeration of bacteriophages. In summary, concentrations of FIB bacteriophages in various sources were consistently lower than FIB, but more reflective of infectious enteric virus levels. Our investigation supports use of bacteriophages as viral surrogates especially for wastewater treatment processes, while additional research is needed to clarify their utility as indicators of viral fate and transport in the ambient water. Describes concentrations and removal through environmental and engineered systems of bacteriophages, fecal indicator bacteria and viral pathogens.

APRI and FIB-4 are good predictors of the stage of liver fibrosis in chronic hepatitis B: the Chronic Hepatitis Cohort Study (CHeCS).

PubMed

Teshale, E; Lu, M; Rupp, L B; Holmberg, S D; Moorman, A C; Spradling, P; Vijayadeva, V; Boscarino, J A; Schmidt, M A; Gordon, S C

2014-12-01

We aim to determine the predictive ability of APRI, FIB-4 and AST/ALT ratio for staging of liver fibrosis and to differentiate significant fibrosis (F2-F4) from none to minimal fibrosis (F0-F1) in chronic hepatitis B (CHB). Liver biopsy results were mapped to an F0-4 equivalent fibrosis stage. Mean APRI and FIB-4 scores were significantly higher for each successive fibrosis level from F1 to F4 (P < 0.05). Based on optimized cut-offs, the AUROCs in distinguishing F2-F4 from F0 to F1 were 0.81 (0.76-0.87) for APRI, 0.81 (0.75-0.86) for FIB-4 and 0.56 (0.49-0.64) for AST/ALT ratio. APRI and FIB-4 distinguished F2-F4 from F0 to F1 with good sensitivity and specificity and can be useful for treatment decisions and monitoring progression of fibrosis. © 2014 John Wiley & Sons Ltd.

Microscopic neural image registration based on the structure of mitochondria

NASA Astrophysics Data System (ADS)

Cao, Huiwen; Han, Hua; Rao, Qiang; Xiao, Chi; Chen, Xi

2017-02-01

Microscopic image registration is a key component of the neural structure reconstruction with serial sections of neural tissue. The goal of microscopic neural image registration is to recover the 3D continuity and geometrical properties of specimen. During image registration, various distortions need to be corrected, including image rotation, translation, tissue deformation et.al, which come from the procedure of sample cutting, staining and imaging. Furthermore, there is only certain similarity between adjacent sections, and the degree of similarity depends on local structure of the tissue and the thickness of the sections. These factors make the microscopic neural image registration a challenging problem. To tackle the difficulty of corresponding landmarks extraction, we introduce a novel image registration method for Scanning Electron Microscopy (SEM) images of serial neural tissue sections based on the structure of mitochondria. The ellipsoidal shape of mitochondria ensures that the same mitochondria has similar shape between adjacent sections, and its characteristic of broad distribution in the neural tissue guarantees that landmarks based on the mitochondria distributed widely in the image. The proposed image registration method contains three parts: landmarks extraction between adjacent sections, corresponding landmarks matching and image deformation based on the correspondences. We demonstrate the performance of our method with SEM images of drosophila brain.

DOE Office of Scientific and Technical Information (OSTI.GOV)

V Yashchuk; R Conley; E Anderson

Verification of the reliability of metrology data from high quality X-ray optics requires that adequate methods for test and calibration of the instruments be developed. For such verification for optical surface profilometers in the spatial frequency domain, a modulation transfer function (MTF) calibration method based on binary pseudo-random (BPR) gratings and arrays has been suggested [1] and [2] and proven to be an effective calibration method for a number of interferometric microscopes, a phase shifting Fizeau interferometer, and a scatterometer [5]. Here we describe the details of development of binary pseudo-random multilayer (BPRML) test samples suitable for characterization of scanningmore » (SEM) and transmission (TEM) electron microscopes. We discuss the results of TEM measurements with the BPRML test samples fabricated from a WiSi2/Si multilayer coating with pseudo-randomly distributed layers. In particular, we demonstrate that significant information about the metrological reliability of the TEM measurements can be extracted even when the fundamental frequency of the BPRML sample is smaller than the Nyquist frequency of the measurements. The measurements demonstrate a number of problems related to the interpretation of the SEM and TEM data. Note that similar BPRML test samples can be used to characterize X-ray microscopes. Corresponding work with X-ray microscopes is in progress.« less

Method to deterministically study photonic nanostructures in different experimental instruments.

PubMed

Husken, B H; Woldering, L A; Blum, C; Vos, W L

2009-01-01

We describe an experimental method to recover a single, deterministically fabricated nanostructure in various experimental instruments without the use of artificially fabricated markers, with the aim to study photonic structures. Therefore, a detailed map of the spatial surroundings of the nanostructure is made during the fabrication of the structure. These maps are made using a series of micrographs with successively decreasing magnifications. The graphs reveal intrinsic and characteristic geometric features that can subsequently be used in different setups to act as markers. As an illustration, we probe surface cavities with radii of 65 nm on a silica opal photonic crystal with various setups: a focused ion beam workstation; a scanning electron microscope (SEM); a wide field optical microscope and a confocal microscope. We use cross-correlation techniques to recover a small area imaged with the SEM in a large area photographed with the optical microscope, which provides a possible avenue to automatic searching. We show how both structural and optical reflectivity data can be obtained from one and the same nanostructure. Since our approach does not use artificial grids or markers, it is of particular interest for samples whose structure is not known a priori, like samples created solely by self-assembly. In addition, our method is not restricted to conducting samples.

Silver nanoparticle production by Rhizopus stolonifer and its antibacterial activity against extended spectrum {beta}-lactamase producing (ESBL) strains of Enterobacteriaceae

DOE Office of Scientific and Technical Information (OSTI.GOV)

Banu, Afreen; Rathod, Vandana, E-mail: drvandanarathod@rediffmail.com; Ranganath, E.

Highlights: {yields} Silver nanoparticle production by using Rhizopus stolonifer. {yields} Antibacterial activity of silver nanoparticles against extended spectrum {beta}-lactamase producing (ESBL) strains of Enterobacteriaceae. {yields} Synergistic effect of antibiotics with silver nanoparticles towards ESBL-strains. {yields} Characterization of silver nanoparticles made by UV-vis spectra, scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transformed infrared (FTIR) spectroscopy, atomic force microscopy (AFM). -- Abstract: This report focuses on the synthesis of silver nanoparticles using the fungus, Rhizopus stolonifer and its antimicrobial activity. Research in nanotechnology highlights the possibility of green chemistry pathways to produce technologically important nanomaterials. Characterization of newly synthesized silvermore » nanoparticles was made by UV-visible absorption spectroscopy, scanning electron microscope (SEM), transmission electron microscope (TEM), Fourier transform infrared (FTIR) spectroscopy and atomic force microscope (AFM). TEM micrograph revealed the formation of spherical nanoparticles with size ranging between 3 and 20 nm. The biosynthesized silver nanoparticles (AgNPs) showed excellent antibacterial activity against ESBL-strains which includes E. coli, Proteus. sp. and Klebsiella sp.« less

Scanning electron microscope analysis of gunshot defects to bone: an underutilized source of information on ballistic trauma.

PubMed

Rickman, John M; Smith, Martin J

2014-11-01

Recent years have seen increasing involvement by forensic anthropologists in the interpretation of skeletal trauma. With regard to ballistic injuries, there is now a large literature detailing gross features of such trauma; however, less attention has been given to microscopic characteristics. This article presents analysis of experimentally induced gunshot trauma in animal bone (Bos taurus scapulae) using full metal jacket (FMJ), soft point (SP), and captive bolt projectiles. The results were examined using scanning electron microscopy (SEM). Additional analysis was conducted on a purported parietal gunshot lesion in a human cranial specimen. A range of features was observed in these samples suggesting that fibrolamellar bone response to projectile impact is analogous to that observed in synthetic composite laminates. The results indicate that direction of bullet travel can be discerned microscopically even when it is ambiguous on gross examination. It was also possible to distinguish SP from FMJ lesions. SEM analysis is therefore recommended as a previously underexploited tool in the analysis of ballistic trauma. © 2014 American Academy of Forensic Sciences.

The microscopic (optical and SEM) examination of dental calculus deposits (DCD). Potential interest in forensic anthropology of a bio-archaeological method.

PubMed

Charlier, Philippe; Huynh-Charlier, Isabelle; Munoz, Olivia; Billard, Michel; Brun, Luc; de la Grandmaison, Geoffroy Lorin

2010-07-01

This article describes the potential interest in forensic anthropology of the microscopic analysis of dental calculus deposits (DCD), a calcified residue frequently found on the surface of teeth. Its sampling and analysis seem straightforward and relatively reproducible. Samples came from archaeological material (KHB-1 Ra's al-Khabbah and RH-5 Ra's al-Hamra, two Prehistoric graveyards located in the Sultanate of Oman, dated between the 5th and 4th millennium B.C.; Montenzio Vecchia, an Etruscan-Celtic necropolis from the north of Italy, dated between the 5th and 3rd century B.C.; body rests of Agnès Sorel, French royal mistress died in 1450 A.D.; skeleton of Pierre Hazard, French royal notary from the 15th century A.D.). Samples were studies by direct optical microscope (OM) or scanning electron microscopy (SEM). Many cytological, histological and elemental analyses were possible, producing precious data for the identification of these remains, the reconstitution of their alimentation and occupational habits, and propositions for manner of death. Copyright 2010 Elsevier Ireland Ltd. All rights reserved.

Experimental analysis of two-layered dissimilar metals by roll bonding

NASA Astrophysics Data System (ADS)

Zhao, Guanghui; Li, Yugui; Li, Juan; Huang, Qingxue; Ma, Lifeng

2018-02-01

Rolling reduction and base layers thickness have important implications for rolling compounding. A two-layered 304 stainless steel/Q345R low alloyed steel was roll bonded. The roll bonding was performed at the three thickness reductions of 25%, 40% and 55% with base layers of various thicknesses (Q345R). The microstructures of the composite were investigated by the ultra-deep microscope (OM) and scanning electron microscope (SEM) and Transmission electron microscope (TEM). Simultaneously, the mechanical properties of the composite were experimentally measured and the tensile fracture surfaces were observed by SEM. The interfaces were successfully bonded without any cracking or voids, which indicated a good fabrication of the 304/Q345R composite. The rolling reduction rate and thinning increase of the substrate contributed to the bonding effects appearance of the roll bonded sheet. The Cr and Ni enriched diffusion layer was formed by the interface elements diffusion. The Cr and Ni diffusion led to the formation of ˜10 μm wide Cr and Ni layers on the carbon steel side.

SEM visualization of glycosylated surface molecules using lectin-coated microspheres

NASA Technical Reports Server (NTRS)

Duke, J.; Janer, L.; Campbell, M.

1985-01-01

There are several techniques currently used to localize glycosylated surface molecules by scanning electron microscopy (Grinnell, 1980; Molday, 1976; Linthicum and Sell, 1975; Nicolson, 1974; Lo Buglio, et al, 1972). A simple and rapid method, using a modification of Grinnell's technique is reported here. Essentially, microspheres coated with Concavalin A are used to bind to glycosylated regions of the palatal shelf epithelium and are visualized in the scanning electron microscope (SEM).

Neural Network for Nanoscience Scanning Electron Microscope Image Recognition.

PubMed

Modarres, Mohammad Hadi; Aversa, Rossella; Cozzini, Stefano; Ciancio, Regina; Leto, Angelo; Brandino, Giuseppe Piero

2017-10-16

In this paper we applied transfer learning techniques for image recognition, automatic categorization, and labeling of nanoscience images obtained by scanning electron microscope (SEM). Roughly 20,000 SEM images were manually classified into 10 categories to form a labeled training set, which can be used as a reference set for future applications of deep learning enhanced algorithms in the nanoscience domain. The categories chosen spanned the range of 0-Dimensional (0D) objects such as particles, 1D nanowires and fibres, 2D films and coated surfaces, and 3D patterned surfaces such as pillars. The training set was used to retrain on the SEM dataset and to compare many convolutional neural network models (Inception-v3, Inception-v4, ResNet). We obtained compatible results by performing a feature extraction of the different models on the same dataset. We performed additional analysis of the classifier on a second test set to further investigate the results both on particular cases and from a statistical point of view. Our algorithm was able to successfully classify around 90% of a test dataset consisting of SEM images, while reduced accuracy was found in the case of images at the boundary between two categories or containing elements of multiple categories. In these cases, the image classification did not identify a predominant category with a high score. We used the statistical outcomes from testing to deploy a semi-automatic workflow able to classify and label images generated by the SEM. Finally, a separate training was performed to determine the volume fraction of coherently aligned nanowires in SEM images. The results were compared with what was obtained using the Local Gradient Orientation method. This example demonstrates the versatility and the potential of transfer learning to address specific tasks of interest in nanoscience applications.

Temporal and spatial patterns for surf zone bacteria before and after disinfection of the orange county sanitation district effluent

USGS Publications Warehouse

Robertson, G.L.; Noble, M.A.; Xu, J. P.; Rosenfeld, L.K.; McGee, C.D.

2005-01-01

Data from pre- and post-disinfection fecal indicator bacteria (FIB) samples from final effluent, an offshore ocean outfall, and surf zone stations off Huntington Beach, CA were compared. Analysis of the results from these data sets confirmed that the ocean outfall was not the FIB source responsible for the postings and closures of local beaches that have occurred each summer since 1999. While FIB counts in the final effluent and offshore showed several order of magnitude reductions after disinfection, there were no significant reductions at the nearby surf zone stations. Additionally, the FIB spectral patterns suggest different sources. The dominant fortnightly cycle suggested that the source was related to the wetting and draining of the land from large spring tide tidal excursions.

Focused ion beam system

DOEpatents

Leung, Ka-Ngo; Gough, Richard A.; Ji, Qing; Lee, Yung-Hee Yvette

1999-01-01

A focused ion beam (FIB) system produces a final beam spot size down to 0.1 .mu.m or less and an ion beam output current on the order of microamps. The FIB system increases ion source brightness by properly configuring the first (plasma) and second (extraction) electrodes. The first electrode is configured to have a high aperture diameter to electrode thickness aspect ratio. Additional accelerator and focusing electrodes are used to produce the final beam. As few as five electrodes can be used, providing a very compact FIB system with a length down to only 20 mm. Multibeamlet arrangements with a single ion source can be produced to increase throughput. The FIB system can be used for nanolithography and doping applications for fabrication of semiconductor devices with minimum feature sizes of 0.1 .mu.m or less.

Focused ion beam system

DOEpatents

Leung, K.; Gough, R.A.; Ji, Q.; Lee, Y.Y.

1999-08-31

A focused ion beam (FIB) system produces a final beam spot size down to 0.1 {mu}m or less and an ion beam output current on the order of microamps. The FIB system increases ion source brightness by properly configuring the first (plasma) and second (extraction) electrodes. The first electrode is configured to have a high aperture diameter to electrode thickness aspect ratio. Additional accelerator and focusing electrodes are used to produce the final beam. As few as five electrodes can be used, providing a very compact FIB system with a length down to only 20 mm. Multibeamlet arrangements with a single ion source can be produced to increase throughput. The FIB system can be used for nanolithography and doping applications for fabrication of semiconductor devices with minimum feature sizes of 0.1 m or less. 13 figs.

Multifunctional carbon nanoelectrodes fabricated by focused ion beam milling.

PubMed

Thakar, Rahul; Weber, Anna E; Morris, Celeste A; Baker, Lane A

2013-10-21

We report a strategy for fabrication of sub-micron, multifunctional carbon electrodes and application of these electrodes as probes for scanning electrochemical microscopy (SECM) and scanning ion conductance microscopy (SICM). The fabrication process utilized chemical vapor deposition of parylene, followed by thermal pyrolysis to form conductive carbon and then further deposition of parylene to form an insulation layer. To achieve well-defined electrode geometries, two methods of electrode exposure were utilized. In the first method, carbon probes were masked in polydimethylsiloxane (PDMS) to obtain a cone-shaped electrode. In the second method, the electrode area was exposed via milling with a focused ion beam (FIB) to reveal a carbon ring electrode, carbon ring/platinum disk electrode, or carbon ring/nanopore electrode. Carbon electrodes were batch fabricated (~35/batch) through the vapor deposition process and were characterized with scanning electron microscopy (SEM), scanning transmission electron microscopy (STEM), and cyclic voltammetry (CV) measurements. Additionally, Raman spectroscopy was utilized to examine the effects of Ga(+) ion implantation, a result of FIB milling. Constant-height, feedback mode SECM was performed with conical carbon electrodes and carbon ring electrodes. We demonstrate the utility of carbon ring/nanopore electrodes with SECM-SICM to simultaneously collect topography, ion current and electrochemical current images. In addition, carbon ring/nanopore electrodes were utilized in substrate generation/tip collection (SG/TC) SECM. In SG/TC SECM, localized delivery of redox molecules affords a higher resolution, than when the redox molecules are present in the bath solution. Multifunctional geometries of carbon electrode probes will find utility in electroanalytical applications, in general, and more specifically with electrochemical microscopy as discussed herein.

Relationship between virological response and FIB-4 index in chronic hepatitis B patients with entecavir therapy.

PubMed

Li, Ni; Xu, Jing-Hang; Yu, Min; Wang, Sa; Si, Chong-Wen; Yu, Yan-Yan

2015-11-21

To investigate whether long-term low-level hepatitis B virus (HBV) DNA influences dynamic changes of the FIB-4 index in chronic hepatitis B (CHB) patients receiving entecavir (ETV) therapy with partial virological responses. We retrospectively analyzed 231 nucleos(t)ide (NA) naïve CHB patients from our previous study (NCT01926288) who received continuous ETV or ETV maleate therapy for three years. The patients were divided into partial virological response (PVR) and complete virological response (CVR) groups according to serum HBV DNA levels at week 48. Seventy-six patients underwent biopsies at baseline and at 48 wk. The performance of the FIB-4 index and area under the receiver operating characteristic (AUROC) curve for predicting fibrosis were determined for the patients undergoing biopsy. The primary objective of the study was to compare the cumulative probabilities of virological responses between the two groups during the treatment period. The secondary outcome was to observe dynamic changes of the FIB-4 index between CVR patients and PVR patients. For hepatitis B e antigen (HBeAg)-positive patients (n = 178), the cumulative probability of achieving undetectable levels at week 144 was 95% and 69% for CVR and PVR patients, respectively (P < 0.001). In the Cox proportional hazards model, a lower pretreatment serum HBV DNA level was an independent factor predicting maintained viral suppression. The cumulative probability of achieving undetectable levels of HBV DNA for HBeAg-negative patients (n = 53) did not differ between the two groups. The FIB-4 index efficiently identified fibrosis, with an AUROC of 0.80 (95%CI: 0.69-0.89). For HBeAg-positive patients, the FIB-4 index was higher in CVR patients than in PVR patients at baseline (1.89 ± 1.43 vs 1.18 ± 0.69, P < 0.001). There was no significant difference in the reduction of the FIB-4 index between the CVR and PVR groups from weeks 48 to 144 (-0.11 ± 0.47 vs -0.13 ± 0.49, P = 0.71). At week 144, the FIB-4 index levels were similar between the two groups (1.24 ± 0.87 vs 1.02 ± 0.73, P = 0.06). After multivariate logistic regression analysis, a lower baseline serum HBV DNA level was associated with improvement of liver fibrosis. In HBeAg-negative patients, the FIB-4 index did not differ between the two groups. The cumulative probabilities of HBV DNA responses showed significant differences between CVR and PVR HBeAg-positive CHB patients undergoing entecavir treatment for 144 wk. However, long-term low-level HBV DNA did not deteriorate the FIB-4 index, which was used to evaluate liver fibrosis, at the end of three years.

Development of critical dimension measurement scanning electron microscope for ULSI (S-8000 series)

NASA Astrophysics Data System (ADS)

Ezumi, Makoto; Otaka, Tadashi; Mori, Hiroyoshi; Todokoro, Hideo; Ose, Yoichi

1996-05-01

The semiconductor industry is moving from half-micron to quarter-micron design rules. To support this evolution, Hitachi has developed a new critical dimension measurement scanning electron microscope (CD-SEM), the model S-8800 series, for quality control of quarter- micron process lines. The new CD-SEM provides detailed examination of process conditions with 5 nm resolution and 5 nm repeatability (3 sigma) at accelerating voltage 800 V using secondary electron imaging. In addition, a newly developed load-lock system has a capability of achieving a high sample throughput of 20 wafers/hour (5 point measurements per wafer) under continuous operation. To support user friendliness, the system incorporates a graphical user interface (GUI), an automated pattern recognition system which helps locating measurement points, both manual and semi-automated operation, and user-programmable operating parameters.

Local dynamic range compensation for scanning electron microscope imaging system by sub-blocking multiple peak HE with convolution.

PubMed

Sim, K S; Teh, V; Tey, Y C; Kho, T K

2016-11-01

This paper introduces new development technique to improve the Scanning Electron Microscope (SEM) image quality and we name it as sub-blocking multiple peak histogram equalization (SUB-B-MPHE) with convolution operator. By using this new proposed technique, it shows that the new modified MPHE performs better than original MPHE. In addition, the sub-blocking method consists of convolution operator which can help to remove the blocking effect for SEM images after applying this new developed technique. Hence, by using the convolution operator, it effectively removes the blocking effect by properly distributing the suitable pixel value for the whole image. Overall, the SUB-B-MPHE with convolution outperforms the rest of methods. SCANNING 38:492-501, 2016. © 2015 Wiley Periodicals, Inc. © Wiley Periodicals, Inc.

Large scale ZnTe nanostructures on polymer micro patterns via capillary force photolithography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Florence, S. Sasi, E-mail: sshanmugaraj@jazanu.edu.sa; Can, N.; Adam, H.

2016-06-10

A novel approach to prepare micro patterns ZnTe nanostructures on Si (100) substrate using thermal evaporation is proposed by capillary Force Lithography (CFL) technique on a self-assembled sacrificial Polystyrene mask. Polystyrene thin films on Si substrates are used to fabricate surface micro-relief patterns. ZnTe nanoparticles have been deposited by thermal evaporation method. The deposited ZnTe nanoparticles properties were assessed by Atomic Force Microscope (AFM), Scanning Electron Microscope (SEM). SEM studies indicated that the particles are uniform in size and shape, well dispersed and spherical in shape. This study reports the micro-arrays of ZnTe nanoparticles on a self-assembled sacrificial PS maskmore » using a capillary flow photolithography process which showed excellent, morphological properties which can be used in photovoltaic devices for anti-reflection applications.« less

Resizing metal-coated nanopores using a scanning electron microscope.

PubMed

Chansin, Guillaume A T; Hong, Jongin; Dusting, Jonathan; deMello, Andrew J; Albrecht, Tim; Edel, Joshua B

2011-10-04

Electron beam-induced shrinkage provides a convenient way of resizing solid-state nanopores in Si(3) N(4) membranes. Here, a scanning electron microscope (SEM) has been used to resize a range of different focussed ion beam-milled nanopores in Al-coated Si(3) N(4) membranes. Energy-dispersive X-ray spectra and SEM images acquired during resizing highlight that a time-variant carbon deposition process is the dominant mechanism of pore shrinkage, although granular structures on the membrane surface in the vicinity of the pores suggest that competing processes may occur. Shrinkage is observed on the Al side of the pore as well as on the Si(3) N(4) side, while the shrinkage rate is observed to be dependent on a variety of factors. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Age as a Confounding Factor for the Accurate Non-Invasive Diagnosis of Advanced NAFLD Fibrosis.

PubMed

McPherson, Stuart; Hardy, Tim; Dufour, Jean-Francois; Petta, Salvatore; Romero-Gomez, Manuel; Allison, Mike; Oliveira, Claudia P; Francque, Sven; Van Gaal, Luc; Schattenberg, Jörn M; Tiniakos, Dina; Burt, Alastair; Bugianesi, Elisabetta; Ratziu, Vlad; Day, Christopher P; Anstee, Quentin M

2017-05-01

Non-invasive fibrosis scores are widely used to identify/exclude advanced fibrosis in patients with non-alcoholic fatty liver disease (NAFLD). However, these scores were principally developed and validated in patients aged between 35 and 65 years of age. The objective of this study was to assess the effect of age on the performance of non-invasive fibrosis tests in NAFLD. Patients were recruited from European specialist hepatology clinics. The cohort was divided into five age-based groups: ≤35 (n=74), 36-45 (n=96), 46-55 (n=197), 56-64 (n=191), and ≥65 years (n=76), and the performance of the aspartate aminotransferase (AST)/alanine transaminase (ALT) ratio, fibrosis 4 (FIB-4), and NAFLD fibrosis score (NFS) for advanced fibrosis (stage F3-F4) for each group was assessed using liver biopsy as the standard. Six hundred and thirty-four patients were included. The diagnostic accuracy of the AST/ALT ratio was lower than NFS and FIB-4 in all the age groups. The AST/ALT ratio, NFS, and FIB-4 score performed poorly for a diagnosis of advanced fibrosis in those aged ≤35 years (area under the receiver operating characteristic curves (AUROCs 0.52, 0.52, and 0.60, respectively). For all groups >35 years, AUROCs for advanced fibrosis were similar for the NFS and FIB-4 score (range 0.77-0.84). However, the specificity for advanced fibrosis using the FIB-4 and NFS declined with age, becoming unacceptably low in those aged ≥65 years (35% for FIB-4 and 20% for NFS). New cutoffs were derived (and validated) for those aged ≥65 years, which improved specificity to 70% without adversely affecting sensitivity (FIB-4 2.0, sensitivity 77%; NFS 0.12, sensitivity 80%). The NFS and FIB-4 scores have similar accuracy for advanced fibrosis in patients aged >35 years. However, the specificity for advanced fibrosis is unacceptably low in patients aged ≥65 years, resulting in a high false positive rate. New thresholds for use in patients aged ≥65 years are proposed to address this issue.

Age as a Confounding Factor for the Accurate Non-Invasive Diagnosis of Advanced NAFLD Fibrosis

PubMed Central

McPherson, Stuart; Hardy, Tim; Dufour, Jean-Francois; Petta, Salvatore; Romero-Gomez, Manuel; Allison, Mike; Oliveira, Claudia P; Francque, Sven; Van Gaal, Luc; Schattenberg, Jörn M; Tiniakos, Dina; Burt, Alastair; Bugianesi, Elisabetta; Ratziu, Vlad; Day, Christopher P; Anstee, Quentin M

2017-01-01

OBJECTIVES: Non-invasive fibrosis scores are widely used to identify/exclude advanced fibrosis in patients with non-alcoholic fatty liver disease (NAFLD). However, these scores were principally developed and validated in patients aged between 35 and 65 years of age. The objective of this study was to assess the effect of age on the performance of non-invasive fibrosis tests in NAFLD. METHODS: Patients were recruited from European specialist hepatology clinics. The cohort was divided into five age-based groups: ≤35 (n=74), 36–45 (n=96), 46–55 (n=197), 56–64 (n=191), and ≥65 years (n=76), and the performance of the aspartate aminotransferase (AST)/alanine transaminase (ALT) ratio, fibrosis 4 (FIB-4), and NAFLD fibrosis score (NFS) for advanced fibrosis (stage F3–F4) for each group was assessed using liver biopsy as the standard. RESULTS: Six hundred and thirty-four patients were included. The diagnostic accuracy of the AST/ALT ratio was lower than NFS and FIB-4 in all the age groups. The AST/ALT ratio, NFS, and FIB-4 score performed poorly for a diagnosis of advanced fibrosis in those aged ≤35 years (area under the receiver operating characteristic curves (AUROCs 0.52, 0.52, and 0.60, respectively). For all groups >35 years, AUROCs for advanced fibrosis were similar for the NFS and FIB-4 score (range 0.77–0.84). However, the specificity for advanced fibrosis using the FIB-4 and NFS declined with age, becoming unacceptably low in those aged ≥65 years (35% for FIB-4 and 20% for NFS). New cutoffs were derived (and validated) for those aged ≥65 years, which improved specificity to 70% without adversely affecting sensitivity (FIB-4 2.0, sensitivity 77% NFS 0.12, sensitivity 80%). CONCLUSIONS: The NFS and FIB-4 scores have similar accuracy for advanced fibrosis in patients aged >35 years. However, the specificity for advanced fibrosis is unacceptably low in patients aged ≥65 years, resulting in a high false positive rate. New thresholds for use in patients aged ≥65 years are proposed to address this issue. PMID:27725647

Three-dimensional ultrastructural analyses of anterior pituitary gland expose spatial relationships between endocrine cell secretory granule localization and capillary distribution.

PubMed

Yoshitomi, Munetake; Ohta, Keisuke; Kanazawa, Tomonoshin; Togo, Akinobu; Hirashima, Shingo; Uemura, Kei-Ichiro; Okayama, Satoko; Morioka, Motohiro; Nakamura, Kei-Ichiro

2016-10-31

Endocrine and endothelial cells of the anterior pituitary gland frequently make close appositions or contacts, and the secretory granules of each endocrine cell tend to accumulate at the perivascular regions, which is generally considered to facilitate secretory functions of these cells. However, three-dimensional relationships between the localization pattern of secretory granules and blood vessels are not fully understood. To define and characterize these spatial relationships, we used scanning electron microscopy (SEM) three-dimensional reconstruction method based on focused ion-beam slicing and scanning electron microscopy (FIB/SEM). Full three-dimensional cellular architectures of the anterior pituitary tissue at ultrastructural resolution revealed that about 70% of endocrine cells were in apposition to the endothelial cells, while almost 30% of endocrine cells were entirely isolated from perivascular space in the tissue. Our three-dimensional analyses also visualized the distribution pattern of secretory granules in individual endocrine cells, showing an accumulation of secretory granules in regions in close apposition to the blood vessels in many cases. However, secretory granules in cells isolated from the perivascular region tended to distribute uniformly in the cytoplasm of these cells. These data suggest that the cellular interactions between the endocrine and endothelial cells promote an uneven cytoplasmic distribution of the secretory granules.

UV radiation and CH4 gas detection with a single ZnO:Pd nanowire

NASA Astrophysics Data System (ADS)

Lupan, O.; Adelung, R.; Postica, V.; Ababii, N.; Chow, L.; Viana, B.; Pauporté, T.

2017-02-01

There is an increasing demand for sensors to monitor environmental levels of ultraviolet (UV) radiation and pollutant gases. In this work, an individual nanowire of Pd modified ZnO nanowire (ZnO:Pd NW) was integrated in a nanosensor device for efficient and fast detection of UV light and CH4 gas at room temperature. Crystalline ZnO:Pd nanowire/nanorod arrays were synthesized onto fluorine doped tin oxide (FTO) substrates by electrochemical deposition (ECD) at relative low-temperatures (90 °C) with different concentrations of PdCl2 in electrolyte solution and investigated by SEM and EDX. Nanodevices were fabricated using dual beam focused electron/ion beam (FIB/SEM) system and showed improved UV radiation response compared to pristine ZnO NW, reported previously by our group. The UV response was increased by one order in magnitude (≈ 11) for ZnO:Pd NW. Gas sensing measurements demonstrated a higher gas response and rapidity to methane (CH4 gas, 100 ppm) at room temperature, showing promising results for multifunctional applications. Also, due to miniature size and ultra-low power consumption of these sensors, it is possible to integrate them into portable devices easily, such as smartphones, digital clock, flame detection, missile lunching and other smart devices.

Catalyst-free one step synthesis of large area vertically stacked N-doped graphene-boron nitride heterostructures from biomass source.

PubMed

Esteve-Adell, Ivan; He, Jinbao; Ramiro, Fernando; Atienzar, Pedro; Primo, Ana; García, Hermenegildo

2018-03-01

A procedure for the one-step preparation of films of few-layer N-doped graphene on top of nanometric hexagonal boron nitride sheets ((N)graphene/h-BN) based on the pyrolysis at 900 °C under an inert atmosphere of a film of chitosan containing about 20 wt% of ammonium borate salt as a precursor is reported. During the pyrolysis a spontaneous segregation of (N)graphene and boron nitride layers takes place. The films were characterized by optical microscopy that shows a thin graphene overlayer covering the boron nitride layer, the latter showing characteristic cracks, and by XPS measurements at different monitoring angles from 0° to 50° where an increase in the proportion of C vs. B and N was observed. The resulting (N)graphene/h-BN films were also characterized by Raman, HRTEM, SEM, FIB-SEM and AFM. The thickness of the (N)graphene and h-BN layers can be controlled by varying the concentration of precursors and the spin coating rate and is typically below 5 nm. Electrical conductivity measurements using microelectrodes can cause the burning of the graphene layer at high intensities, while lower intensities show that (N)graphene/h-BN films behave as capacitors in the range of positive voltages.

Microcavity surface plasmon resonance bio-sensors

NASA Astrophysics Data System (ADS)

Mosavian, Nazanin

This work discusses a miniature surface plasmon biosensor which uses a dielectric sub- micron diameter core with gold spherical shell. The shell has a subwavelength nanoaperture believed to excite stationary plasmon resonances at the biosensor's surface. The sub-micron cavity enhances the measurement sensitivity of molecules binding to the sensor surface. We used visible-range optical spectroscopy to study the wavelength shift as bio-molecules absorbed-desorbed at the shell surface. We also used Scanning Electron Microscopy (SEM) and Focused Ion Beam (FIB) ablation to study the characteristics of microcavity surface plasmon resonance sensor (MSPRS) and the inner structure formed with metal deposition and its spectrum. We found that resonances at 580 nm and 670 nm responded to bound test agents and that Surface Plasmon Resonance (SPR) sensor intensity could be used to differentiate between D-glucose and L-glucose. The responsiveness of the system depended upon the mechanical integrity of the metallic surface coating.

Fabrication of nanoelectrodes for neurophysiology: cathodic electrophoretic paint insulation and focused ion beam milling

PubMed Central

Qiao, Yi; Chen, Jie; Guo, Xiaoli; Cantrell, Donald; Ruoff, Rodney; Troy, John

2005-01-01

The fabrication and characterization of tungsten nanoelectrodes insulated with cathodic electrophoretic paint is described together with their application within the field of neurophysiology. The tip of a 127 μm diameter tungsten wire was etched down to less than 100 nm and then insulated with cathodic electrophoretic paint. Focused ion beam (FIB) polishing was employed to remove the insulation at the electrode’s apex, leaving a nanoscale sized conductive tip of 100–1000 nm. The nanoelectrodes were examined by scanning electron microscopy (SEM) and their electrochemical properties characterized by steady state linear sweep voltammetry. Electrode impedance at 1 kHz was measured too. The ability of a 700 nm tipped electrode to record well-isolated action potentials extracellularly from single visual neurons in vivo was demonstrated. Such electrodes have the potential to open new populations of neurons to study. PMID:16467926

In vivo reactive neural plasticity investigation by means of correlative two photon: electron microscopy

NASA Astrophysics Data System (ADS)

Allegra Mascaro, A. L.; Cesare, P.; Sacconi, L.; Grasselli, G.; Mandolesi, G.; Maco, B.; Knott, G.; Huang, L.; De Paola, V.; Strata, P.; Pavone, F. S.

2013-02-01

In the adult nervous system, different populations of neurons correspond to different regenerative behavior. Although previous works showed that olivocerebellar fibers are capable of axonal regeneration in a suitable environment as a response to injury1, we have hitherto no details about the real dynamics of fiber regeneration. We set up a model of singularly axotomized climbing fibers (CF) to investigate their reparative properties in the adult central nervous system (CNS) in vivo. Time lapse two-photon imaging has been combined to laser nanosurgery2, 3 to define a temporal pattern of the degenerative event and to follow the structural rearrangement after injury. To characterize the damage and to elucidate the possible formation of new synaptic contacts on the sprouted branches of the lesioned CF, we combined two-photon in vivo imaging with block face scanning electron microscopy (FIB-SEM). Here we describe the approach followed to characterize the reactive plasticity after injury.

Transmission Electron Microscopy of Cometary Residues from Micron-Sized Craters in the Stardust Al-Foils

NASA Technical Reports Server (NTRS)

Leroux, Hugues; Stroud, Rhonda M.; Dai, Zu Rong; Graham, Giles A.; Troadec, David; Bradley, John P.; Teslich, Nick; Borg, Janet; Kearsley, Anton T.; Horz, Friedrich

2008-01-01

We report Transmission Electron Microscopy (TEM) investigations of micro-craters that originated from hypervelocity impacts of comet 81P/Wild 2 dust particles on the aluminium foil of the Stardust collector. The craters were selected by Scanning Electron Microscopy (SEM) and then prepared by Focused Ion Beam (FIB) milling techniques in order to provide electron transparent cross-sections for TEM studies. The crater residues contain both amorphous and crystalline materials in varying proportions and compositions. The amorphous component is interpreted as resulting from shock melting during the impact and the crystalline phases as relict minerals. The latter show evidence for shock metamorphism. Based on the residue morphology and the compositional variation, the impacting particles are inferred to have been dominated by mixtures of submicron olivine, pyroxene and Fe-sulfide grains, in agreement with prior results of relatively coarse-grained mineral assemblages in the aerogel collector.

Development and surface characterization of a glucose biosensor based on a nanocolumnar ZnO film

NASA Astrophysics Data System (ADS)

Rodrigues, A.; Castegnaro, M. V.; Arguello, J.; Alves, M. C. M.; Morais, J.

2017-04-01

Highly oriented nanostructured ZnO films were grown on the surface of stainless steel plates (ZnO/SS) by chemical bath deposition (CBD). The films consisted of vertically aligned ZnO nanocolumns, ∼1 μm long and ∼80 nm wide, as observed by SEM (scanning electron microscopy) and FIB (focused ion beam). XRD (X-ray diffraction) confirmed the c-axis preferred orientation of the ZnO columns, which were functionalized with the glucose oxidase (GOx) enzyme into a biosensor of glucose. The electrochemical response studied by CV (cyclic voltammetry) proved that the biosensor was capable of detecting glucose from 1.5 up to 16 mM concentration range. XPS (X-ray photoelectron spectroscopy) analysis, excited with synchrotron radiation, probed the atom specific chemical environment at the electrode's surface and shed some light on the nature of the ZnO-GOx interaction.

A Complex Endomembrane System in the Archaeon Ignicoccus hospitalis Tapped by Nanoarchaeum equitans

DOE PAGES

Heimerl, Thomas; Flechsler, Jennifer; Pickl, Carolin; ...

2017-06-13

Based on serial sectioning, focused ion beam scanning electron microscopy (FIB/SEM), and electron tomography, we depict in detail the highly unusual anatomy of the marine hyperthermophilic crenarchaeon, Ignicoccus hospitalis. Our data support a complex and dynamic endomembrane system consisting of cytoplasmic protrusions, and with secretory function. Moreover, we reveal that the cytoplasm of the putative archaeal ectoparasite Nanoarchaeum equitans can get in direct contact with this endomembrane system, complementing and explaining recent proteomic, transcriptomic and metabolomic data on this inter-archaeal relationship. In addition, we identified a matrix of filamentous structures and/or tethers in the voluminous inter-membrane compartment (IMC) of I.more » hospitalis, which might be responsible for membrane dynamics. Overall, this unusual cellular compartmentalization, ultrastructure and dynamics in an archaeon that belongs to the recently proposed TACK superphylum prompts speculation that the eukaryotic endomembrane system might originate from Archaea.« less

Correlative Tomography

PubMed Central

Burnett, T. L.; McDonald, S. A.; Gholinia, A.; Geurts, R.; Janus, M.; Slater, T.; Haigh, S. J.; Ornek, C.; Almuaili, F.; Engelberg, D. L.; Thompson, G. E.; Withers, P. J.

2014-01-01

Increasingly researchers are looking to bring together perspectives across multiple scales, or to combine insights from different techniques, for the same region of interest. To this end, correlative microscopy has already yielded substantial new insights in two dimensions (2D). Here we develop correlative tomography where the correlative task is somewhat more challenging because the volume of interest is typically hidden beneath the sample surface. We have threaded together x-ray computed tomography, serial section FIB-SEM tomography, electron backscatter diffraction and finally TEM elemental analysis all for the same 3D region. This has allowed observation of the competition between pitting corrosion and intergranular corrosion at multiple scales revealing the structural hierarchy, crystallography and chemistry of veiled corrosion pits in stainless steel. With automated correlative workflows and co-visualization of the multi-scale or multi-modal datasets the technique promises to provide insights across biological, geological and materials science that are impossible using either individual or multiple uncorrelated techniques. PMID:24736640

Hybrid chalcogenide nanoparticles: 2D-WS2 nanocrystals inside nested WS2 fullerenes.

PubMed

Hoshyargar, Faegheh; Corrales, Tomas P; Branscheid, Robert; Kolb, Ute; Kappl, Michael; Panthöfer, Martin; Tremel, Wolfgang

2013-10-28

The MOCVD assisted formation of nested WS2 inorganic fullerenes (IF-WS2) was performed by enhancing surface diffusion with iodine, and fullerene growth was monitored by taking TEM snapshots of intermediate products. The internal structure of the core-shell nanoparticles was studied using scanning electron microscopy (SEM) after cross-cutting with a focused ion beam (FIB). Lamellar reaction intermediates were found occluded in the fullerene particles. In contrast to carbon fullerenes, layered metal chalcogenides prefer the formation of planar, plate-like structures where the dangling bonds at the edges are stabilized by excess S atoms. The effects of the reaction and annealing temperatures on the composition and morphology of the final product were investigated, and the strength of the WS2 shell was measured by intermittent contact-mode AFM. The encapsulated lamellar structures inside the hollow spheres may lead to enhanced tribological activities.

Compositional and Microstructural Evolution of Olivine Under Multiple-Cycle Pulsed Laser Irradiation as Revealed by FIB/Field-Emission TEM

NASA Technical Reports Server (NTRS)

Christoffersen, R.; Loeffler, M. J.; Dukes, C. A.; Keller, L. P.; Baragiola, R. A.

2016-01-01

The use of pulsed laser irradiation to simulate the short duration, high-energy conditions characteristic of micrometeorite impacts is now an established approach in experimental space weathering studies. The laser generates both melt and vapor deposits that contain nanophase metallic Fe (npFe(sup 0)) grains with size distributions and optical properties similar to those in natural impact-generated melt and vapor deposits. There remains uncertainty, however, about how well lasers simulate the mechanical work and internal (thermal) energy partitioning that occurs in actual impacts. We are currently engaged in making a direct comparison between the products of laser irradiation and experimental/natural hypervelocity impacts. An initial step reported here is to use analytical SEM and TEM is to attain a better understanding of how the microstructure and composition of laser deposits evolve over multiple cycles of pulsed laser irradiation.

Method for observation of deembedded sections of fish gonad by scanning electron microscopy

NASA Astrophysics Data System (ADS)

Mao, Lian-Ju

2000-09-01

This article reports a method for examining the intracellular structure of fish gonads using a scanning electron microscope(SEM). The specimen preparation procedure is similar to that for transmission electron microscopy wherein samples cut into semi-thin sections are fixed and embedded in plastic. The embedment matrix was removed by solvents. Risen-free specimens could be observed by SEM. The morphology of matured sperms in the gonad was very clear, and the oocyte internal structures appeared in three-dimensional images. Spheroidal nucleoli and yolk vesicles and several bundles of filaments adhered on the nucleoli could be viewed by SEM for the first time.

A SEM-correlation of the anatomy of the vitreous body: making visible the invisible.

PubMed

Jongebloed, W L; Humalda, D; Worst, J F

1986-12-30

The naked human vitreous (sclera, iris and cornea removed) suspended in water does not reveal inner structures. After ink injection into the vitreous, the presence of different compartments and the existence of cisterns becomes evident. A concept of the internal system of cisterns is given on the basis of stereoscopic-lightmicroscopic images. An attempt is made to correlate images of the complete vitreous body, obtained with a stereo-lightmicroscope, with images of segments of cisternal walls produced with a scanning electron-microscope (SEM). A comparison is made between SEM-images of the vitreous bodies of human and rabbit eyes.

Characterization of Polycapillary Optics in a TES Microcalorimeter EDS System Installed on an SEM

NASA Astrophysics Data System (ADS)

Takano, A.; Maehata, K.; Iyomoto, N.; Yasuda, K.; Maeno, H.; Shiiyama, K.; Tanaka, K.

2016-08-01

Energy-dispersive spectroscopic measurements are performed using a superconducting transition-edge sensor (TES) microcalorimeter mounted on a scanning electron microscope (SEM) for advanced research at Kyushu University. Because the sensitive area of the TES microcalorimeter is about 0.02~mm2, polycapillary optics is used to collect the X-rays emitted by the SEM specimen on the TES microcalorimeter. The X-ray transmission efficiency of the polycapillary optics is obtained by analyzing the X-ray energy spectra measured by the TES microcalorimeter. The obtained transmission efficiency of the polycapillary optics is reproduced by the calculated results of the simulation.

The ultrastructure of mono- and holocentric plant centromeres: an immunological investigation by structured illumination microscopy and scanning electron microscopy.

PubMed

Wanner, Gerhard; Schroeder-Reiter, Elizabeth; Ma, Wei; Houben, Andreas; Schubert, Veit

2015-12-01

The spatial distribution of the three centromere-associated proteins α-tubulin, CENH3, and phosphorylated histone H2A (at threonine 120, H2AThr120ph) was analysed by indirect immunodetection at monocentric cereal chromosomes and at the holocentric chromosomes of Luzula elegans by super-resolution light microscopy and scanning electron microscopy (SEM). Using structured illumination microscopy (SIM) as the super-resolution technique on squashed specimens and SEM on uncoated isolated specimens, the three-dimensional (3D) distribution of the proteins was visualized at the centromeres. Technical aspects of 3D SEM are explained in detail. We show that CENH3 forms curved "pads" mainly around the lateral centromeric region in the primary constriction of metacentric chromosomes. H2AThr120ph is present in both the primary constriction and in the pericentromere. α-tubulin-labeled microtubule bundles attach to CENH3-containing chromatin structures, either in single bundles with a V-shaped attachment to the centromere or in split bundles to bordering pericentromeric flanks. In holocentric L. elegans chromosomes, H2AThr120ph is located predominantly in the centromeric groove of each chromatid as proven by subsequent FIB/FESEM ablation and 3D reconstruction. α-tubulin localizes to the edges of the groove. In both holocentric and monocentric chromosomes, no additional intermediate structures between microtubules and the centromere were observed. We established models of the distribution of CENH3, H2AThr120ph and the attachment sites of microtubules for metacentric and holocentric plant chromosomes.

Ultra-high aspect ratio replaceable AFM tips using deformation-suppressed focused ion beam milling.

PubMed

Savenko, Alexey; Yildiz, Izzet; Petersen, Dirch Hjorth; Bøggild, Peter; Bartenwerfer, Malte; Krohs, Florian; Oliva, Maria; Harzendorf, Torsten

2013-11-22

Fabrication of ultra-high aspect ratio exchangeable and customizable tips for atomic force microscopy (AFM) using lateral focused ion beam (FIB) milling is presented. While on-axis FIB milling does allow high aspect ratio (HAR) AFM tips to be defined, lateral milling gives far better flexibility in terms of defining the shape and size of the tip. Due to beam-induced deformation, it has so far not been possible to define HAR structures using lateral FIB milling. In this work we obtain aspect ratios of up to 45, with tip diameters down to 9 nm, by a deformation-suppressing writing strategy. Several FIB milling strategies for obtaining sharper tips are discussed. Finally, assembly of the HAR tips on a custom-designed probe as well as the first AFM scanning is shown.

Measuring and modeling the flux of fecal bacteria across the sediment-water interface in a turbulent stream

NASA Astrophysics Data System (ADS)

Grant, Stanley B.; Litton-Mueller, Rachel M.; Ahn, Jong H.

2011-05-01

Sediments are a pervasive source of fecal indicator bacteria (FIB) in rivers, lakes, estuaries, and oceans and may constitute a long-term reservoir of human disease. Previous attempts to quantify the flux of FIB across the sediment-water interface (SWI) are limited to extreme flow events, for which the primary mechanism of bacterial release is disruption and/or erosion of the sediment substrate. Here we report measurements of FIB flux across the SWI in a turbulent stream that is not undergoing significant erosion. The stream is formed by the steady discharge of bacteria-free disinfected and highly treated wastewater effluent to an earthen channel harboring high concentrations of FIB in the sediment from in situ growth. The flux j″ of FIB across the SWI, estimated from mass balance on FIB measurements in the water column, scales linearly with the concentration of bacteria in sediment pore fluids Cpore over a 3 decade change in both variables: ? The magnitude of the observed mass transfer velocity (? m s-1) is significantly larger than values predicted for either the diffusion of bacteria across a concentration boundary layer (? m s-1) or sweep and eject fluid motions at the SWI (? m s-1) but is similar to the flux of water between the stream and its hyporheic zone estimated from dye injection experiments. These results support the hypothesis that hyporheic exchange controls the trafficking of bacteria, and perhaps other types of particulate organic matter, across the SWI in turbulent streams.

Agrochemicals indirectly increase survival of E. coli O157:H7 and indicator bacteria by reducing ecosystem services.

PubMed

Staley, Zachery R; Rohr, Jason R; Senkbeil, Jacob K; Harwood, Valerie J

Storm water and agricultural runoff frequently contain agrochemicals, fecal indicator bacteria (FIB), and zoonotic pathogens. Entry of such contaminants into aquatic ecosystems may affect ecology and human health. This study tested the hypothesis that the herbicide atrazine and the fungicide chlorothalonil indirectly affect the survival of FIB (Escherichia coli and Enterococcus faecalis) and a pathogen (E. coli O157:H7) by altering densities of protozoan predators or by altering competition from autochthonous bacteria. Streptomycin-resistant E. coli, En. faecalis, and E. coli O157:H7 were added to microcosms composed of Florida river water containing natural protozoan and bacterial populations. FIB, pathogen, and protozoan densities were monitored over six days. Known metabolic inhibitors, cycloheximide and streptomycin, were used to inhibit autochthonous protozoa or bacteria, respectively. The inhibitors made it possible to isolate the effects of predation or competition on survival of allochthonous bacteria, and each treatment increased the survival of FIB and pathogens. Chlorothalonil's effect was similar to that of cycloheximide, significantly reducing protozoan densities and elevating densities of FIB and pathogens relative to the control. Atrazine treatment did not affect protozoan densities, but, through an effect on competition, resulted in significantly greater densities of En. faecalis and E. coli O157:H7. Hence, by reducing predaceous protozoa and bacterial competitors that facilitate purifying water bodies of FIBs and human pathogens, chlorothalonil and atrazine indirectly diminished an ecosystem service of fresh water.

Changes in liver stiffness measurement using acoustic radiation force impulse elastography after antiviral therapy in patients with chronic hepatitis C.

PubMed

Chen, Sheng-Hung; Lai, Hsueh-Chou; Chiang, I-Ping; Su, Wen-Pang; Lin, Chia-Hsin; Kao, Jung-Ta; Chuang, Po-Heng; Hsu, Wei-Fan; Wang, Hung-Wei; Chen, Hung-Yao; Huang, Guan-Tarn; Peng, Cheng-Yuan

2018-01-01

To compare on-treatment and off-treatment parameters acquired using acoustic radiation force impulse elastography, the Fibrosis-4 (FIB-4) index, and aspartate aminotransferase-to-platelet ratio index (APRI) in patients with chronic hepatitis C (CHC). Patients received therapies based on pegylated interferon or direct-acting antiviral agents. The changes in paired patient parameters, including liver stiffness (LS) values, the FIB-4 index, and APRI, from baseline to sustained virologic response (SVR) visit (24 weeks after the end of treatment) were compared. Multiple regression models were used to identify significant factors that explained the correlations with LS, FIB-4, and APRI values and SVR. A total of 256 patients were included, of which 219 (85.5%) achieved SVR. The paired LS values declined significantly from baseline to SVR visit in all groups and subgroups except the nonresponder subgroup (n = 10). Body mass index (P = 0.0062) and baseline LS (P < 0.0001) were identified as independent factors that explained the LS declines. Likewise, the baseline FIB-4 (P < 0.0001) and APRI (P < 0.0001) values independently explained the declines in the FIB-4 index and APRI, respectively. Moreover, interleukin-28B polymorphisms, baseline LS, and rapid virologic response were identified as independent correlates with SVR. Paired LS measurements in patients treated for CHC exhibited significant declines comparable to those in FIB-4 and APRI values. These declines may have correlated with the resolution of necroinflammation. Baseline LS values predicted SVR.

Differential Decay of Cattle-associated Fecal Indicator ...

EPA Pesticide Factsheets

Background: Fecal indicator bacteria (FIB) have a long history of use in the assessment of the microbial quality of recreational waters. However, quantification of FIB provides no information about the pollution source(s) and relatively little is known about their fate in the ambient waters. Microbial source tracking (MST) field has evolved in response to a need to identify pollution source(s), but majority of MST markers suffer from the same caveat as FIB, as our understanding of the factors influencing their fate in the environment is limited. Materials: We assessed the effect of water type (freshwater vs marine) and select environmental parameters (indigenous microbiota, ambient sunlight) on decay of FIB and MST markers from cattle manure. Experiments were conducted in situ using a submersible aquatic mesocosm containing dialysis bags filled with mixture of cattle manure and ambient water. Culturable FIB were enumerated by membrane filtration and via qPCR (Entero1a, EC23S) and MST markers were enumerated via qPCR and included general marker of fecal pollution (GenBac3) and cattle-associated subset (Rum2Bac, CowM2, CowM3). Results: Decay of culturable FIB was significantly faster (P > 0.001) than any of the molecular markers irrespective of the water type or experimental conditions. The water type was a significant factor affecting decay (P: 0.008 to < 0.001), although the magnitude of the effect differed among the microbial targets and over time. Presence o

An improved FIB sample preparation technique for site-specific plan-view specimens: A new cutting geometry.

PubMed

Li, Chen; Habler, Gerlinde; Baldwin, Lisa C; Abart, Rainer

2018-01-01

Focused ion beam (FIB) sample preparation technique in plan-view geometry allows direct correlations of the atomic structure study via transmission electron microscopy with micrometer-scale property measurements. However, one main technical difficulty is that a large amount of material must be removed underneath the specimen. Furthermore, directly monitoring the milling process is difficult unless very large material volumes surrounding the TEM specimen site are removed. In this paper, a new cutting geometry is introduced for FIB lift-out sample preparation with plan-view geometry. Firstly, an "isolated" cuboid shaped specimen is cut out, leaving a "bridge" connecting it with the bulk material. Subsequently the two long sides of the "isolated" cuboid are wedged, forming a triangular prism shape. A micromanipulator needle is used for in-situ transfer of the specimen to a FIB TEM grid, which has been mounted parallel with the specimen surface using a simple custom-made sample slit. Finally, the grid is transferred to the standard FIB grid holder for final thinning with standard procedures. This new cutting geometry provides clear viewing angles for monitoring the milling process, which solves the difficulty of judging whether the specimen has been entirely detached from the bulk material, with the least possible damage to the surrounding materials. With an improved success rate and efficiency, this plan-view FIB lift-out specimen preparation technique should have a wide application for material science. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

FIB Secondary Etching Method for Fabrication of Fine CNT Forest Metamaterials

NASA Astrophysics Data System (ADS)

Pander, Adam; Hatta, Akimitsu; Furuta, Hiroshi

2017-10-01

Anisotropic materials, like carbon nanotubes (CNTs), are the perfect substitutes to overcome the limitations of conventional metamaterials; however, the successful fabrication of CNT forest metamaterial structures is still very challenging. In this study, a new method utilizing a focused ion beam (FIB) with additional secondary etching is presented, which can obtain uniform and fine patterning of CNT forest nanostructures for metamaterials and ranging in sizes from hundreds of nanometers to several micrometers. The influence of the FIB processing parameters on the morphology of the catalyst surface and the growth of the CNT forest was investigated, including the removal of redeposited material, decreasing the average surface roughness (from 0.45 to 0.15 nm), and a decrease in the thickness of the Fe catalyst. The results showed that the combination of FIB patterning and secondary etching enabled the growth of highly aligned, high-density CNT forest metamaterials. The improvement in the quality of single-walled CNTs (SWNTs), defined by the very high G/D peak ratio intensity of 10.47, demonstrated successful fine patterning of CNT forest for the first time. With a FIB patterning depth of 10 nm and a secondary etching of 0.5 nm, a minimum size of 150 nm of CNT forest metamaterials was achieved. The development of the FIB secondary etching method enabled for the first time, the fabrication of SWNT forest metamaterials for the optical and infrared regime, for future applications, e.g., in superlenses, antennas, or thermal metamaterials.

FibroScan, aspartate aminotransferase and alanine aminotransferase ratio (AAR), aspartate aminotransferase to platelet ratio index (APRI), fibrosis index based on the 4 factor (FIB-4), and their combinations in the assessment of liver fibrosis in patients with hepatitis B.

PubMed

Ding, Deping; Li, Hongbing; Liu, Ping; Chen, Lingli; Kang, Jian; Zhang, Yinhua; Ma, Deqiang; Chen, Yue; Luo, Jie; Meng, Zhongji

2015-01-01

The aim of this study was to assess the effects of FibroScan, aspartate aminotransferase and alanine aminotransferase ratio (AAR), aspartate aminotransferase to platelet ratio index (APRI), fibrosis index based on the 4 factor (FIB-4) and their combinations on liver fibrosis in patients with hepatitis B. 406 hospitalized patients with chronic hepatitis B (CHB) and cirrhosis in our hospital were analyzed retrospectively and collected patients clinical indicators, including liver stiffness (LS), AAR, APRI and FIB-4, and then compared the differences of these indicators between CHB group and hepatitis B with cirrhosis group. Receiver operating curve (ROC) was used to evaluate the differentiating capacity of these indicators on CHB and liver cirrhosis. Four indicators related to liver cirrhosis had a statistical significance between two groups (P < 0.01); the under ROC curve areas of LS, AAR, APRI and FIB-4 for differential diagnosis of CHB and liver cirrhosis were 0.866, 0.772, 0.632 and 0.885, respectively. The under ROC curve areas of LS, AAR, APRI and FIB-4 for differential diagnosis of liver cirrhosis at compensatory stage and de-compensatory stage were 0.627, 0.666, 0.795 and 0.820, respectively. LS, AAR, APRI and FIB-4 were good indicators as clinical diagnosis and differential diagnosis on hepatitis B related cirrhosis.

Quantitative Secondary Electron Detector (QSED)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nayak, Subu; Joy, David C.

2013-12-31

Research is proposed to investigate the feasibility of applying recent advances in semiconductor technology to fabricate direct digital Quantitative Secondary Electron Detectors (QSED) for scanning electron microscopes (SEMs). If successful, commercial versions of the QSED would transform the SEM into a quantitative, metrological system with enhanced capabilities that, in turn, would broaden research horizons across industries. This project will be conducted in collaboration with Dr. David C Joy at the University of Tennessee, who has demonstrated limited (to the 1keV range) digital collection of the energy from backscattered signals in a SEM using a modified silicon drift detector. Several detectormore » configurations will be fabricated and tested for sensitivities, background noise reduction, DC offset elimination, and metrological capabilities (linearity, accuracy, etc.) against a set of commercially important performance criteria to ascertain concept feasibility. Once feasibility is proven, the solid state digital device array and its switching frequency will be scaled-up, in Phase II, to improve temporal resolution. If successful, this work will produce a crucial advancement in electron microscopy with wide-ranging applications. The following are key advantages anticipated from direct digital QSED: 1. High signal-to-noise ratio will improve SEM resolution in nano-scale, which is critical for dimensional metrology in any application. 2. Quantitative measurement will enhance process control and design validation in semiconductors, photo-voltaics, bio-medical devices and catalysts; and will improve accuracy in predicting the reliability and the lifecycle of materials across industries. 3. Video and dynamic-imaging capabilities will advance study in nano-scale phenomena in a variety of industries, including pharmaceutical and semiconductor materials. 4. Lower cost will make high-performing electron microscopes affordable to more researchers. 5. Compact size and ease of integration with imaging software will enable customers to retrofit and upgrade existing SEM equipment. ScienceTomorrow’s direct digital QSED concept has generated enthusiastic interest among a number of microscope makers, service companies, and microscope users. The company has offers of support from several companies. The roles these companies would play in supporting the project are described in the proposal. The proposed QSED advance sits squarely in the middle of ScienceTomorrow’s mission to provide next-generation technology solutions to today’s critical problems and, if successful, will further the company’s business strategy by launching an advanced, high-margin product that will enable the company and its partners to create at least 17 net-new jobs by the end of 2018.« less

PSU/WES Interlaboratory Comparative Methodology Study of an Experimental Cementitious Repository Seal Material. Report 2. Final Results.

DTIC Science & Technology

1982-03-01

meter 25 11.0 Microstructure by SEM 11.1 Introduction In order to correlate observed physical and mechanical properties in cured grout samples, a...studied at the two laboratories has proper physical properties , phase composi- tions, and microstructures for the materials used and ages covered...Scanning Electron Microscope Resolution Test Specimen ( Al -W) D. B. Ballard Research Material 100 SEM Resolution Test Specimen (AI-W)., is an alloy of

Visual force sensing with flexible nanowire buckling springs

NASA Astrophysics Data System (ADS)

Dobrokhotov, Vladimir V.; Yazdanpanah, Mehdi M.; Pabba, Santosh; Safir, Abdelilah; Cohn, Robert W.

2008-01-01

A calibrated method of force sensing is demonstrated in which the buckled shape of a long flexible metallic nanowire, referred to as a 'nanoneedle', is interpreted to determine the applied force. An individual needle of 157 nm diameter by 15.6 µm length is grown on an atomic force microscope (AFM) cantilever with a desired orientation (by the method of Yazdanpanah et al 2005 J. Appl. Phys. 98 073510). Using a nanomanipulator the needle is buckled in the chamber of a scanning electron microscope (SEM) and the buckled shapes are recorded in SEM images. Force is determined as a function of deflection for an assumed elastic modulus by fitting the shapes using the generalized elastica model (De Bona and Zelenika 1997 Proc. Inst. Mech. Eng. C 211 509-17). In this calibration the elastic modulus (68.3 GPa) was determined using an auxiliary AFM measurement, with the needle in the same orientation as in the SEM. Following this calibration the needle was used as a sensor in a different orientation than the AFM coordinates to deflect a suspended PLLA polymer fiber from which the elastic modulus (2.96 GPa) was determined. The practical value of the sensing method does depend on the reliability and ruggedness of the needle. In this study the same needle remained rigidly secured to the AFM cantilever throughout the entire SEM/AFM calibration procedure and the characterization of the nanofiber.

Comparison of marginal fit of cemented zirconia copings manufactured after digital impression with lava™ C.O.S and conventional impression technique.

PubMed

Dauti, Rinet; Cvikl, Barbara; Franz, Alexander; Schwarze, Uwe Yacine; Lilaj, Bledar; Rybaczek, Tina; Moritz, Andreas

2016-12-08

Evaluation of the marginal fit of cemented zirconia copings manufactured after digital impression with Lava™ Chairside Oral Scanner in comparison to that of zirconia copings manufactured after conventional impressions with polyvinyl siloxane. A prepared typodont tooth #36, was replicated 40 times with a vinyl silicone and precise model resin. The dies were randomly divided into two groups according to the impression taking technique. Digital impressions with Lava™ C.O.S. and conventional impressions were taken according to the group. Subsequently zirconia copings were manufactured and cemented on their respective dies with zinc oxide phosphate cement. After embedding in resin, mesio-distal section of each coping was performed with a diamond saw in order to obtain two slices. One half of the specimen was used for evaluation with an optical microscope (OM) and the other half for evaluation with a scanning electron microscope (SEM). Marginal gap (MG) and absolute marginal discrepancy (AMD) were measured mesial and distal on each slice. No significant difference of the marginal parameters between the digital and the conventional group was found. The mean values for MG in the digital group were 96.28 μm (+/-43.21 μm) measured with the OM and 99.26 μm (+/-48.73 μm) measured with the SEM, respectively. AMD mean values were 191.54 μm (+/-85.42 μm) measured with the optical microscope and 211.6 μm (+/-96.55 μm) with the SEM. For the conventional group the mean MG values were 94.84 μm (+/-50.77 μm) measured with the OM and 83.37 μm (+/-44.38 μm) measured with the SEM, respectively. AMD mean values were 158.60 μm (+/-69.14 μm) for the OM and 152.72 μm (+/-72.36) for the SEM. Copings manufactured after digital impression with Lava™ C.O.S. show comparable marginal parameters with the copings manufactured after conventional impression with polyvinyl syloxane. The mean MG values of both groups fit in the clinically acceptable range.

Loading of fecal indicator bacteria in North Carolina tidal creek headwaters: hydrographic patterns and terrestrial runoff relationships.

PubMed

Stumpf, Curtis H; Piehler, Michael F; Thompson, Suzanne; Noble, Rachel T

2010-09-01

In the New River Estuary (NRE) in eastern North Carolina (NC), fecal indicator bacteria (FIB) levels exceed water quality standards, leading to closure of estuarine waters for shellfishing and classification of parts of the estuary as "impaired" per the Clean Water Act section 303(d) list. As a means to investigate fecal contamination and loading of FIB to the NRE, a continuous automated sampler (ISCO) outfitted with flow modules and water quality probes was placed in four first-order tidal creek headwaters. Total storm discharge and bacterial load for Escherichia coli (EC) and Enterococcus spp. (ENT) were calculated using graphical volumetric flow calculations and interpolation of FIB measurements over each storm's duration for 10 storms. Mean total load of 10(9)-10(12) EC and ENT cells (MPN) occurred over the course of each storm. Total storm loading, averaged across all storms, was as much as 30 and 37 times greater than equivalent duration of baseflow loading for EC and ENT, respectively. Within the first 30% of creek storm volume for all storms and all creeks combined, a mean cumulative load of only 37% and 44% of the total EC and ENT cells, respectively, was discharged, indicating these creeks are not demonstrating a 'first flush' scenario for FIB. The median storm Event Mean Concentrations (EMCs) were 6.37 × 10(2) and 2.03 × 10(2) MPN/100 mL, for EC and ENT, respectively, compared with median baseflow concentrations of 1.48 × 10(2) and 4.84 × 10(1) for EC and ENT, respectively, and were significantly different between base and storm flow events. FIB was correlated with TSS (weak), flow rate (strong), and different stages (base, rising, peak, and falling) of the hydrograph (strong). Pollutographs indicate large intra-storm variability of FIB, and the need for more intensive sampling throughout a storm in order to attain accurate FIB contaminant estimates. Instream sediment concentrations ranged from 5 to 478 (MPN/g) and 13 to 776 (MPN/g) for EC and ENT, respectively, indicating sediment as a source, but a minor reservoir. This overall approach for calculating loading in headwater tidal creeks is detailed. Accurate loading characterization of FIB during storms and dry weather conditions, and understanding intra-storm FIB concentrations, is imperative for understanding patterns of water quality impairment, establishing management planning, and developing appropriate mitigation strategies. Copyright © 2010 Elsevier Ltd. All rights reserved.

Staging liver fibrosis in chronic hepatitis B with T1 relaxation time index on gadoxetic acid-enhanced MRI: Comparison with aspartate aminotransferase-to-platelet ratio index and FIB-4.

PubMed

Yang, Li; Ding, Ying; Rao, Shengxiang; Chen, Caizhong; Wu, Lifang; Sheng, Ruofan; Fu, Caixia; Zeng, Mengsu

2017-04-01

To assess the accuracy of the T 1 relaxation time index on gadoxetic acid-enhanced magnetic resonance imaging (MRI) for staging liver fibrosis in chronic hepatitis B (CHB), in comparison and combination with the aspartate aminotransferase-to-platelet ratio index (APRI) and fibrosis-4 (FIB-4). A retrospective study of gadoxetic acid-enhanced T 1 mapping and serum biochemical tests was performed on 126 CHB patients who underwent gadoxetic acid-enhanced 1.5T MRI, and the histological score used as the gold standard. The reduction rate of T 1 relaxation time before and 20 minutes after gadoxetic acid injection (ΔT 1 , ΔR1%), the contrast uptake rate (K Hep ), APRI, and FIB-4 were calculated. The diagnostic efficacy of ΔT 1 , ΔR1%, K Hep , APRI, and FIB-4 for predicting stage 2 or greater (≥S2), stage 3 or greater (≥S3), and stage 4 (S4) was compared. ΔT 1 (r = -0.513, P < 0.001), ΔR1% (r = -0.626, P < 0.001), K Hep (r = -0.527, P < 0.001), APRI (r = 0.519, P < 0.001), and FIB-4 (r = 0.476, P < 0.001) correlated significantly with fibrosis stages. Areas under the curves (AUCs) of ΔR1% for detecting ≥S2, ≥S3, and S4 were 0.849, 0.827, and 0.809, which were greater than that of APRI (0.763, 0.745, 0.787) and FIB-4 (0.727, 0.738, 0.772), but significant difference was found only in discriminating ≥S2 between ΔR1% and FIB-4 (P = 0.027). The combination of all five indices performed best, with AUC, sensitivity, and specificity of 0.860, 87.21%, and 72.50% for diagnosing ≥S2, 0.878, 82.81%, and 85.48% for ≥S3, and 0.867, 80.00%, and 83.95% for S4. The gadoxetic acid-enhanced T 1 relaxation time index appears to be superior to APRI and FIB-4 for predicting hepatic fibrosis. The combined use of gadoxetic acid-enhanced T 1 mapping, APRI, and FIB-4 may be more reliable for staging liver fibrosis in CHB. 4 J. Magn. Reson. Imaging 2017;45:1186-1194. © 2016 International Society for Magnetic Resonance in Medicine.

Evaluation of APRI and FIB-4 for noninvasive assessment of significant fibrosis and cirrhosis in HBeAg-negative CHB patients with ALT ≤ 2 ULN

PubMed Central

Li, Qiang; Ren, Xiaojing; Lu, Chuan; Li, Weixia; Huang, Yuxian; Chen, Liang

2017-01-01

Abstract To evaluate the performance of aspartate transaminase-to-platelet ratio index (APRI) and fibrosis index based on four factors (FIB-4) to predict significant fibrosis and cirrhosis in hepatitis B virus e antigen (HBeAg)-negative chronic hepatitis B (CHB) patients with alanine transaminase (ALT) ≤ twice the upper limit of normal (2 ULN). Histologic and laboratory data of 236 HBeAg-negative CHB patients with ALT ≤ 2 ULN were analyzed. Predicted fibrosis stage, based on established scales and cut-offs for APRI and FIB-4, was compared with METAVIR scores obtained from liver biopsy. In this study, the areas under the receiver operating characteristic curves (AUROCs) of APRI were lower than that of FIB-4 (0.62 vs 0.69; P = 0.019) for diagnosing significant fibrosis; however APRI and FIB-4 were comparable for diagnosing cirrhosis (0.77 vs 0.81; P = 0.374). When the cut-off proposed by WHO HBV guideline for APRI (>2.0) was used, no cirrhotic patients were correctly predicted. For FIB-4, the WHO proposed cut-off of 3.25 correctly identified significant fibrosis 83% of the time; but for APRI, the WHO proposed cut-off of 1.5 identified significant fibrosis 56%. In ruling out significant fibrosis, the WHO proposed APRI cut-off of 0.5 had a predictive value of 39%, and the FIB-4 cut-off of 1.45 correctly identified lack of significant fibrosis in 47% of the patients. In this study, based on ROC analysis, the optimal cut-offs were 0.46 and 0.65 for APRI, and 1.05 and 1.29 for FIB-4, for diagnosing significant fibrosis and cirrhosis, respectively. When the new cut-off of APRI (>0.65) was used, 82% of the cirrhotic patients were correctly predicted. In ruling out significant fibrosis, the new APRI cut-off (<0.46) had a predictive value of 80%, and new FIB-4 cut-off (<1.05) correctly identified lack of significant fibrosis in 84% of the patients. The WHO guidelines proposed cut-offs might be higher for HBeAg-negative CHB patients with ALT ≤2 ULN, and might underestimate the proportion of significant fibrosis and cirrhosis. A new set of cut-offs should be used to predict significant fibrosis and cirrhosis in this specific population. PMID:28328813

Evaluation of APRI and FIB-4 for noninvasive assessment of significant fibrosis and cirrhosis in HBeAg-negative CHB patients with ALT ≤ 2 ULN: A retrospective cohort study.

PubMed

Li, Qiang; Ren, Xiaojing; Lu, Chuan; Li, Weixia; Huang, Yuxian; Chen, Liang

2017-03-01

To evaluate the performance of aspartate transaminase-to-platelet ratio index (APRI) and fibrosis index based on four factors (FIB-4) to predict significant fibrosis and cirrhosis in hepatitis B virus e antigen (HBeAg)-negative chronic hepatitis B (CHB) patients with alanine transaminase (ALT) ≤ twice the upper limit of normal (2 ULN).Histologic and laboratory data of 236 HBeAg-negative CHB patients with ALT ≤ 2 ULN were analyzed. Predicted fibrosis stage, based on established scales and cut-offs for APRI and FIB-4, was compared with METAVIR scores obtained from liver biopsy.In this study, the areas under the receiver operating characteristic curves (AUROCs) of APRI were lower than that of FIB-4 (0.62 vs 0.69; P = 0.019) for diagnosing significant fibrosis; however APRI and FIB-4 were comparable for diagnosing cirrhosis (0.77 vs 0.81; P = 0.374). When the cut-off proposed by WHO HBV guideline for APRI (>2.0) was used, no cirrhotic patients were correctly predicted. For FIB-4, the WHO proposed cut-off of 3.25 correctly identified significant fibrosis 83% of the time; but for APRI, the WHO proposed cut-off of 1.5 identified significant fibrosis 56%. In ruling out significant fibrosis, the WHO proposed APRI cut-off of 0.5 had a predictive value of 39%, and the FIB-4 cut-off of 1.45 correctly identified lack of significant fibrosis in 47% of the patients. In this study, based on ROC analysis, the optimal cut-offs were 0.46 and 0.65 for APRI, and 1.05 and 1.29 for FIB-4, for diagnosing significant fibrosis and cirrhosis, respectively. When the new cut-off of APRI (>0.65) was used, 82% of the cirrhotic patients were correctly predicted. In ruling out significant fibrosis, the new APRI cut-off (<0.46) had a predictive value of 80%, and new FIB-4 cut-off (<1.05) correctly identified lack of significant fibrosis in 84% of the patients.The WHO guidelines proposed cut-offs might be higher for HBeAg-negative CHB patients with ALT ≤2 ULN, and might underestimate the proportion of significant fibrosis and cirrhosis. A new set of cut-offs should be used to predict significant fibrosis and cirrhosis in this specific population.

Inactivation of faecal indicator bacteria in a roof-captured rainwater system under ambient meteorological conditions.

PubMed

Ahmed, W; Richardson, K; Sidhu, J P S; Jagals, P; Toze, S

2014-01-01

In this study, faecal indicator bacteria (FIB) namely Escherichia coli and Enterococcus spp. were seeded into slurries of possum faeces and placed on the roof and in the gutter of a roof-captured rainwater (RCR) system. The persistence of FIB in these circumstances was determined under ambient climatic conditions. FIB persistence was also determined under in situ conditions in tank water using diffusion chambers. The numbers of surviving FIB at different time intervals were enumerated using culture-based methods. Both FIB were rapidly inactivated on the roof under sunlight conditions (T(90) = 2 h) compared with shade conditions (T(90) = 9-53 h). Significant differences were observed between sunlight and shade conditions on the roof for both T90 values of E. coli (P < 0·001) and Enterococcus spp. (P < 0·001). E. coli showed biphasic inactivation patterns under both clean and unclean gutter conditions. Enterococcus spp., however, showed rapid inactivation (T(90) = 2 h for the clean gutter and T(90) = 6 h for the unclean gutter) compared with E. coli (T(90) = 22 h for the clean gutter and T(90) = 20 h for the unclean gutter). Significant differences were also observed between the T(90) values of E. coli and Enterococcus spp. for both clean (P < 0·001) and unclean (P < 0·001) gutters. Both E. coli and Enterococcus spp. showed nonlinear biphasic inactivation in tank water. Significant difference was observed between the T(90) value of E. coli inactivation compared with Enterococcus spp. (P < 0·001) in the tank water. In this study, FIB were observed to survive longer (T(90) = 9-53 h) on the roof under shade conditions compared with sunlight conditions (T(90) = 2 h). If there is a rainfall event within two to three days after the deposition of faecal maters on the roof, it is highly likely that FIB would be transported to the tank water. When introduced into the tank, a relatively slow inactivation process may take place (T(90) = 38-72 h). The presence of FIB in water indicates faecal pollution and potential presence of enteric pathogens. Therefore, the information on the resilience of FIB, as obtained in this study, can be used for indirect assessment of health risks associated with using roof-captured rainwater for potable and nonpotable purposes. © 2013 The Society for Applied Microbiology.

The Relationship between Hydroclimatic Variables and Faecal Indicator Bacteria in River Basins in Pakistan and Bangladesh

NASA Astrophysics Data System (ADS)

Hofstra, Nynke; Shahid Iqbal, M.; Majedul Islam, M. M.

2016-04-01

Water contaminated with pathogenic bacteria causing diarrhoea poses a health risk to the population. Worldwide, diarrhoea is the 3rd leading cause of death. A changing climate may increase the concentration of pathogens in surface water. Increased temperature will mostly increase the inactivation of pathogens and therefore decrease the surface water concentration. Increased precipitation may dilute contaminated water, but may also increase the runoff of pathogens into the surface water. Decreased precipitation may have the opposite effect. Moreover, increased chance of extreme precipitation events and increased risk of floods may also increase the runoff of pathogens into the surface water. The net balance of these effects is uncertain. The objective of our study is to quantify the relationship between hydroclimatic variables (surface air and water temperature, precipitation and runoff) and faecal indicator bacteria (FIB, E. coli and Enterococci) in two rivers in Pakistan and Bangladesh. In these countries health problems are large, particularly in annual periods of flood. We studied FIB instead of pathogens, because of the costs associated with pathogen measurements. The relationship between FIB and hydroclimatic variables is expected to be comparable to the relationship between pathogens and hydroclimatic variables. For both regions the FIB concentrations have been monitored for two years between 2013 and 2015 at several points in the rivers. Concentrations of FIB in Kabul (Pakistan) and Betna (Bangladesh) river basins are very high (up to 5.2 log10 cfu/100ml). Due to a broken waste water treatment system of the city of Peshawar, concentrations are higher in Kabul than in the Betna river. All hydroclimatic variables positively correlate with FIB. An unexpected positive relation with temperature can be explained by the fact that temperature and discharge increase at the same time and possibly FIB growth. The positive relation with precipitation and discharge shows that not the dilution, but the increased runoff of FIB is more important. Regression models for each of the measurement locations in Kabul river show that water temperature, discharge and precipitation together explain a large part of the variance (R2 equals 0.72-0.94) for E. coli. The regression model for Betna river comprises water temperature and discharge and for E. coli R2=0.47 and for Enterococci R2=0.49. We can conclude that FIB concentrations increase with increasing temperature and particularly precipitation and discharge. We expect pathogen concentrationss to increase in a similar way and would therefore expect increased health risk due to climate change in Kabul and Betna river basins.

ENVIRONMENTALLY FRIENDLY LEATHER TANNING USING ENZYMES

EPA Science Inventory

The effectiveness of the leather tanning will be evaluated by measuring shrinkage temperature, and analyzing leather structure using Scan Electron Microscope (SEM). The team will also measure leather physical/mechanical properties, including softness, tensile strength, elon...

Synchronized voltage contrast display analysis system

NASA Technical Reports Server (NTRS)

Johnston, M. F.; Shumka, A.; Miller, E.; Evans, K. C. (Inventor)

1982-01-01

An apparatus and method for comparing internal voltage potentials of first and second operating electronic components such as large scale integrated circuits (LSI's) in which voltage differentials are visually identified via an appropriate display means are described. More particularly, in a first embodiment of the invention a first and second scanning electron microscope (SEM) are configured to scan a first and second operating electronic component respectively. The scan pattern of the second SEM is synchronized to that of the first SEM so that both simultaneously scan corresponding portions of the two operating electronic components. Video signals from each SEM corresponding to secondary electron signals generated as a result of a primary electron beam intersecting each operating electronic component in accordance with a predetermined scan pattern are provided to a video mixer and color encoder.

Predictive Power of Clean Bed Filtration Theory for Fecal Indicator Bacteria Removal in Stormwater Biofilters

NASA Astrophysics Data System (ADS)

Parker, E.; Rippy, M.; Mehring, A.; Winfrey, B.; Ambrose, R. F.; Levin, L. A.; Grant, S. B.

2017-12-01

Green infrastructure (also referred to as low impact development, or LID) has the potential to transform urban stormwater runoff from an environmental threat to a valuable water resource. Here we focus on the removal of fecal indicator bacteria (FIB, a pollutant responsible for runoff associated inland and coastal beach closures) in stormwater biofilters (a common type of green infrastructure). Drawing on a combination of previously published and new laboratory studies of FIB removal in biofilters, we find that 66% of the variance in FIB removal rates can be explained by clean bed filtration theory (CBFT, 31%), antecedent dry period (14%), study effect (8%), biofilter age (7%), and the presence or absence of shrubs (6%). Our analysis suggests that, with the exception of shrubs, plants affect FIB removal indirectly by changing the infiltration rate, not directly by changing the FIB removal mechanisms or altering filtration rates in ways not already accounted for by CBFT. The analysis presented here represents a significant step forward in our understanding of how physicochemical theories (such as CBFT) can be melded with hydrology, engineering design, and ecology to improve the water quality benefits of green infrastructure.