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Sample records for electron microscopy suggests

  1. Electron Microscopy.

    Science.gov (United States)

    Beer, Michael

    1980-01-01

    Reviews technical aspects of structure determination in biological electron microscopy (EM). Discusses low dose EM, low temperature microscopy, electron energy loss spectra, determination of mass or molecular weight, and EM of labeled systems. Cites 34 references. (CS)

  2. Single-particle electron microscopy structure of UDP-glucose:glycoprotein glucosyltransferase suggests a selectivity mechanism for misfolded proteins.

    Science.gov (United States)

    Calles-Garcia, Daniel; Yang, Meng; Soya, Naoto; Melero, Roberto; Ménade, Marie; Ito, Yukishige; Vargas, Javier; Lukacs, Gergely L; Kollman, Justin M; Kozlov, Guennadi; Gehring, Kalle

    2017-07-07

    The enzyme UDP-glucose:glycoprotein glucosyltransferase (UGGT) mediates quality control of glycoproteins in the endoplasmic reticulum by attaching glucose to N-linked glycan of misfolded proteins. As a sensor, UGGT ensures that misfolded proteins are recognized by the lectin chaperones and do not leave the secretory pathway. The structure of UGGT and the mechanism of its selectivity for misfolded proteins have been unknown for 25 years. Here, we used negative-stain electron microscopy and small-angle X-ray scattering to determine the structure of UGGT from Drosophila melanogaster at 18-Å resolution. Three-dimensional reconstructions revealed a cage-like structure with a large central cavity. Particle classification revealed flexibility that precluded determination of a high-resolution structure. Introduction of biotinylation sites into a fungal UGGT expressed in Escherichia coli allowed identification of the catalytic and first thioredoxin-like domains. We also used hydrogen-deuterium exchange mass spectrometry to map the binding site of an accessory protein, Sep15, to the first thioredoxin-like domain. The UGGT structural features identified suggest that the central cavity contains the catalytic site and is lined with hydrophobic surfaces. This enhances the binding of misfolded substrates with exposed hydrophobic residues and excludes folded proteins with hydrophilic surfaces. In conclusion, we have determined the UGGT structure, which enabled us to develop a plausible functional model of the mechanism for UGGT's selectivity for misfolded glycoproteins. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  3. Electron Microscopy Center (EMC)

    Data.gov (United States)

    Federal Laboratory Consortium — The Electron Microscopy Center (EMC) at Argonne National Laboratory develops and maintains unique capabilities for electron beam characterization and applies those...

  4. Scanning ultrafast electron microscopy

    OpenAIRE

    Yang, Ding-Shyue; Mohammed, Omar F.; Zewail, Ahmed H.

    2010-01-01

    Progress has been made in the development of four-dimensional ultrafast electron microscopy, which enables space-time imaging of structural dynamics in the condensed phase. In ultrafast electron microscopy, the electrons are accelerated, typically to 200 keV, and the microscope operates in the transmission mode. Here, we report the development of scanning ultrafast electron microscopy using a field-emission-source configuration. Scanning of pulses is made in the single-electron mode, for whic...

  5. Electronic detectors for electron microscopy.

    Science.gov (United States)

    Faruqi, A R; Henderson, R

    2007-10-01

    Due to the increasing popularity of electron cryo-microscopy (cryoEM) in the structural analysis of large biological molecules and macro-molecular complexes and the need for simple, rapid and efficient readout, there is a persuasive need for improved detectors. Commercial detectors, based on phosphor/fibre optics-coupled CCDs, provide adequate performance for many applications, including electron diffraction. However, due to intrinsic light scattering within the phosphor, spatial resolution is limited. Careful measurements suggest that CCDs have superior performance at lower resolution while all agree that film is still superior at higher resolution. Consequently, new detectors are needed based on more direct detection, thus avoiding the intermediate light conversion step required for CCDs. Two types of direct detectors are discussed in this review. First, there are detectors based on hybrid technology employing a separate pixellated sensor and readout electronics connected with bump bonds-hybrid pixel detectors (HPDs). Second, there are detectors, which are monolithic in that sensor and readout are all in one plane (monolithic active pixel sensor, MAPS). Our discussion is centred on the main parameters of interest to cryoEM users, viz. detective quantum efficiency (DQE), resolution or modulation transfer function (MTF), robustness against radiation damage, speed of readout, signal-to-noise ratio (SNR) and the number of independent pixels available for a given detector.

  6. Scanning ultrafast electron microscopy.

    Science.gov (United States)

    Yang, Ding-Shyue; Mohammed, Omar F; Zewail, Ahmed H

    2010-08-24

    Progress has been made in the development of four-dimensional ultrafast electron microscopy, which enables space-time imaging of structural dynamics in the condensed phase. In ultrafast electron microscopy, the electrons are accelerated, typically to 200 keV, and the microscope operates in the transmission mode. Here, we report the development of scanning ultrafast electron microscopy using a field-emission-source configuration. Scanning of pulses is made in the single-electron mode, for which the pulse contains at most one or a few electrons, thus achieving imaging without the space-charge effect between electrons, and still in ten(s) of seconds. For imaging, the secondary electrons from surface structures are detected, as demonstrated here for material surfaces and biological specimens. By recording backscattered electrons, diffraction patterns from single crystals were also obtained. Scanning pulsed-electron microscopy with the acquired spatiotemporal resolutions, and its efficient heat-dissipation feature, is now poised to provide in situ 4D imaging and with environmental capability.

  7. Single particle electron microscopy

    NARCIS (Netherlands)

    Boekema, Egbert J.; Folea, Mihaela; Kouril, Roman

    2009-01-01

    Electron microscopy (EM) in combination with image analysis is a powerful technique to study protein structures at low, medium, and high resolution. Since electron micrographs of biological objects are very noisy, improvement of the signal-to-noise ratio by image processing is an integral part of

  8. and transmission electron microscopy

    African Journals Online (AJOL)

    Administrator

    immune-electron microscopy (IEM) from patients' feces. They reported this virus particle as the causative agent of winter vomiting outbreaks in Norwalk (Kapikian et al.,. 1972). This is the remarkable landmark study of non- bacterial gastroenteritis viruses, especially for small round structured viruses (SRSVs). After that, many.

  9. Suggestive evidence of a vesicle-mediated mode of cell degranulation in chromaffin cells. A high-resolution scanning electron microscopy investigation

    Science.gov (United States)

    Crivellato, Enrico; Solinas, Paola; Isola, Raffaella; Ribatti, Domenico; Riva, Alessandro

    2010-01-01

    In this study we used a modified osmium maceration method for high-resolution scanning electron microscopy to study some ultrastructural details fitting the schema of piecemeal degranulation in chromaffin cells. Piecemeal degranulation refers to a particulate pattern of cell secretion that is accomplished by vesicle-mediated extracellular transport of granule-stored material. We investigated adrenal samples from control and angiotensin II-treated rats, and identified a variable proportion of smooth, 30–60-nm-diameter vesicles in the cytoplasm of chromaffin cells. A percentage of these vesicles were interspersed in the cytosol among chromaffin granules but the majority appeared to be attached to granules. Remarkably, the number of unattached cytoplasmic vesicles was greatly increased in chromaffin cells from angiotensin II-treated animals. Vesicles of the same structure and dimension were detected close to or attached to the cytoplasmic face of the plasma membrane; these, too, were increased in number in chromaffin cells from rats stimulated with angiotensin II. In specimens shaken with a rotating agitator during maceration, the cytoplasmic organelles could be partially removed and the fine structure of the vesicular interaction with the inner side of the plasma membrane emerged most clearly. A proportion of chromaffin granules showed protrusions that we interpreted as vesicular structures budding from the granular envelope. In some instances, the transection plane intersected granules with putative vesicles emerging from the surfaces. In these cases, the protrusions of budding vesicles could be observed from the internal side. This study provides high-resolution scanning electron microscopy images compatible with a vesicle-mediated degranulation mode of cell secretion in adrenal chromaffin cells. The data indicating an increase in the number of vesicles observed in chromaffin cells after stimulation with the chromaffin cell secretagogue angiotensin II suggests

  10. Electronic detectors for electron microscopy.

    Science.gov (United States)

    Faruqi, A R; McMullan, G

    2011-08-01

    Electron microscopy (EM) is an important tool for high-resolution structure determination in applications ranging from condensed matter to biology. Electronic detectors are now used in most applications in EM as they offer convenience and immediate feedback that is not possible with film or image plates. The earliest forms of electronic detector used routinely in transmission electron microscopy (TEM) were charge coupled devices (CCDs) and for many applications these remain perfectly adequate. There are however applications, such as the study of radiation-sensitive biological samples, where film is still used and improved detectors would be of great value. The emphasis in this review is therefore on detectors for use in such applications. Two of the most promising candidates for improved detection are: monolithic active pixel sensors (MAPS) and hybrid pixel detectors (of which Medipix2 was chosen for this study). From the studies described in this review, a back-thinned MAPS detector appears well suited to replace film in for the study of radiation-sensitive samples at 300 keV, while Medipix2 is suited to use at lower energies and especially in situations with very low count rates. The performance of a detector depends on the energy of electrons to be recorded, which in turn is dependent on the application it is being used for; results are described for a wide range of electron energies ranging from 40 to 300 keV. The basic properties of detectors are discussed in terms of their modulation transfer function (MTF) and detective quantum efficiency (DQE) as a function of spatial frequency.

  11. Electron microscopy of viruses.

    Science.gov (United States)

    Laue, Michael

    2010-01-01

    Electron microscopy is widely used in virology because viruses are generally too small for a direct inspection by light microscopy. Analysis of virus morphology is necessary in many circumstances, e.g., for the diagnosis of a virus in particular clinical situations or the analysis of virus entry and assembly. Moreover, quality control of virus particle integrity is required if a virus is propagated in cell culture, particularly if the virus genome has changed. In most cases already the basic methodology for transmission electron microscopy, i.e., negative staining and ultrathin sectioning, is sufficient to give relevant information on virus ultrastructure. This chapter gives detailed information on the principles of these basic methodologies and provides simple but reliable protocols for a quick start. Moreover, the description of standard protocols for negative staining and ultrathin sectioning are supplemented by protocols on immuno-negative staining and rapid ultrathin sectioning. Finally, principles of methods for an extended ultrastructural research using more elaborate techniques, such as cryotechniques or methods to reveal the three-dimensional virus architecture, are briefly reviewed. Copyright © 2010 Elsevier Inc. All rights reserved.

  12. Direct electron detection in transmission electron microscopy

    OpenAIRE

    Jin, Liang

    2009-01-01

    Since the first prototype of a transmission electron microscope was built in 1931 by Ernst Ruska and Max Knoll, Transmission Electron Microscopy (TEM) has proved to be an essential imaging tool for physicists, material scientists, and biologists. To record the TEM images for analysis, electron microscopists have used specialized electron micrograph film for a long time, until the new developments in TEM, such as electron tomography and cryo- electron microscopy, pushed for the needs of digita...

  13. Holography and transmission electron microscopy

    OpenAIRE

    Matteucci, G.; Pozzi, G.; Tonomura, A.

    1993-01-01

    The basic principles and methods of off-axis electron holography are presented and illustrated by means of three examples related to its application in high resolution electron microscopy and the investigation of electric and magnetic fields in thin specimens.

  14. Advanced computing in electron microscopy

    CERN Document Server

    Kirkland, Earl J

    2010-01-01

    This book features numerical computation of electron microscopy images as well as multislice methods High resolution CTEM and STEM image interpretation are included in the text This newly updated second edition will bring the reader up to date on new developments in the field since the 1990's The only book that specifically addresses computer simulation methods in electron microscopy

  15. Electronic Blending in Virtual Microscopy

    Science.gov (United States)

    Maybury, Terrence S.; Farah, Camile S.

    2010-01-01

    Virtual microscopy (VM) is a relatively new technology that transforms the computer into a microscope. In essence, VM allows for the scanning and transfer of glass slides from light microscopy technology to the digital environment of the computer. This transition is also a function of the change from print knowledge to electronic knowledge, or as…

  16. High-resolution electron microscopy

    CERN Document Server

    Spence, John C H

    2013-01-01

    This new fourth edition of the standard text on atomic-resolution transmission electron microscopy (TEM) retains previous material on the fundamentals of electron optics and aberration correction, linear imaging theory (including wave aberrations to fifth order) with partial coherence, and multiple-scattering theory. Also preserved are updated earlier sections on practical methods, with detailed step-by-step accounts of the procedures needed to obtain the highest quality images of atoms and molecules using a modern TEM or STEM electron microscope. Applications sections have been updated - these include the semiconductor industry, superconductor research, solid state chemistry and nanoscience, and metallurgy, mineralogy, condensed matter physics, materials science and material on cryo-electron microscopy for structural biology. New or expanded sections have been added on electron holography, aberration correction, field-emission guns, imaging filters, super-resolution methods, Ptychography, Ronchigrams, tomogr...

  17. Illuminating Electron Microscopy of Photocatalysts

    DEFF Research Database (Denmark)

    Cavalca, Filippo

    energy into chemical bonds. By means of Transmission Electron Microscopy (TEM) it is possible to gain insight in the fundamentals of their reaction mechanisms, chemical behaviour, structure and morphology before, during and after reaction using in situ investigations. In particular, the environmental TEM...... (ETEM) is the instrument of choice employed in this thesis to perform such studies. Typically, photocatalysts work in gaseous or liquid atmosphere upon light illumination. We aim at reproducing their working conditions in situ. The ETEM allows exposing specimens to a controlled gas atmosphere, thus...... the microscope that allows electron microscopy under nonconventional TEM conditions and new kinds of in situ spectroscopy....

  18. Correlative fluorescence and electron microscopy.

    Science.gov (United States)

    Schirra, Randall T; Zhang, Peijun

    2014-10-01

    Correlative fluorescence and electron microscopy (CFEM) is a multimodal technique that combines dynamic and localization information from fluorescence methods with ultrastructural data from electron microscopy, to give new information about how cellular components change relative to the spatiotemporal dynamics within their environment. In this review, we will discuss some of the basic techniques and tools of the trade for utilizing this attractive research method, which is becoming a very powerful tool for biology labs. The information obtained from correlative methods has proven to be invaluable in creating consensus between the two types of microscopy, extending the capability of each, and cutting the time and expense associated with using each method separately for comparative analysis. The realization of the advantages of these methods in cell biology has led to rapid improvement in the protocols and has ushered in a new generation of instruments to reach the next level of correlation--integration. Copyright © 2014 John Wiley & Sons, Inc.

  19. Correlated Light Microscopy and Electron Microscopy

    NARCIS (Netherlands)

    Sjollema, Klaas A.; Schnell, Ulrike; Kuipers, Jeroen; Kalicharan, Ruby; Giepmans, Ben N. G.; MullerReichert, T; Verkade, P

    2012-01-01

    Understanding where, when, and how biomolecules (inter)act is crucial to uncover fundamental mechanisms in cell biology. Recent developments in fluorescence light microscopy (FLM) allow protein imaging in living cells and at the near molecular level. However, fluorescence microscopy only reveals

  20. ELECTRON MICROSCOPY OF RHODOTORULA GLUTINIS

    Science.gov (United States)

    Thyagarajan, T. R.; Conti, S. F.; Naylor, H. B.

    1962-01-01

    Thyagarajan, T. R. (Dartmouth Medical School, Hanover, N. H.), S. F. Conti, and H. B. Naylor. Electron microscopy of Rhodotorula glutinis. J. Bacteriol. 83:381–394. 1962.—The structure and manner of nuclear division in Rhodotorula glutinis was studied by electron microscopy of ultrathin sections. Parallel studies with the light microscope, employing conventional staining techniques and phase-contrast microscope observations on nuclei in living cells, were carried out. The nucleus is spherical to oval and is bounded by a nuclear membrane. Intranuclear structures, identified as nucleoli, and electron-transparent areas were observed. The nuclear membrane persists throughout the various stages of cell division. Observations of the nucleus with the electron microscope revealed that nuclear division occurs by a process of elongation and constriction similar to that seen in both living and stained cells. The fine structure of mitochondria and other components of the yeast cell and their behavior during cell division are described. The absence of vacuoles in actively dividing cells of Rhodotorula glutinis lends further support to the view that the vacuole is not an integral part of the nucleus. The results with the electron microscope generally support and considerably extend those obtained with living and stained cells. Images PMID:13921132

  1. Bridging fluorescence microscopy and electron microscopy

    NARCIS (Netherlands)

    Giepmans, Ben N. G.

    Development of new fluorescent probes and fluorescence microscopes has led to new ways to study cell biology. With the emergence of specialized microscopy units at most universities and research centers, the use of these techniques is well within reach for a broad research community. A major

  2. Polyethyleneimine as tracer for electron microscopy

    NARCIS (Netherlands)

    Schurer, Jacob Willem

    1980-01-01

    In this thesis the development of a tracer particle for use in electron microscopy is described. Attempts were made to use this tracer particle in immuno-electron microscopy and to trace negatively charged tissue components. ... Zie: Summary

  3. Electron microscopy of pharmaceutical systems.

    Science.gov (United States)

    Klang, Victoria; Valenta, Claudia; Matsko, Nadejda B

    2013-01-01

    During the last decades, the focus of research in pharmaceutical technology has steadily shifted towards the development and optimisation of nano-scale drug delivery systems. As a result, electron microscopic methods are increasingly employed for the characterisation of pharmaceutical systems such as nanoparticles and microparticles, nanoemulsions, microemulsions, solid lipid nanoparticles, different types of vesicles, nanofibres and many more. Knowledge of the basic properties of these systems is essential for an adequate microscopic analysis. Classical transmission and scanning electron microscopic techniques frequently have to be adapted for an accurate analysis of formulation morphology, especially in case of hydrated colloidal systems. Specific techniques such as environmental scanning microscopy or cryo preparation are required for their investigation. Analytical electron microscopic techniques such as electron energy-loss spectroscopy or energy-dispersive X-ray spectroscopy are additional assets to determine the elemental composition of the systems, but are not yet standard tools in pharmaceutical research. This review provides an overview of pharmaceutical systems of interest in current research and strategies for their successful electron microscopic analysis. Advantages and limitations of the different methodological approaches are discussed and recent findings of interest are presented. Copyright © 2012 Elsevier Ltd. All rights reserved.

  4. Epoxy Resins in Electron Microscopy

    Science.gov (United States)

    Finck, Henry

    1960-01-01

    A method of embedding biological specimens in araldite 502 (Ciba) has been developed for materials available in the United States. Araldite-embedded tissues are suitable for electron microscopy, but the cutting qualities of the resin necessitates more than routine attention during microtomy. The rather high viscosity of araldite 502 also seems to be an unnecessary handicap. The less viscous epoxy epon 812 (Shell) produces specimens with improved cutting qualities, and has several features—low shrinkage and absence of specimen damage during cure, minimal compression of sections, relative absence of electron beam-induced section damage, etc.—which recommends it as a routine embedding material. The hardness of the cured resin can be easily adjusted by several methods to suit the materials embedded in it. Several problems and advantages of working with sections of epoxy resins are also discussed. PMID:13822825

  5. Electron microscopy and forensic practice

    Science.gov (United States)

    Kotrlý, Marek; Turková, Ivana

    2013-05-01

    Electron microanalysis in forensic practice ranks among basic applications used in investigation of traces (latents, stains, etc.) from crime scenes. Applying electron microscope allows for rapid screening and receiving initial information for a wide range of traces. SEM with EDS/WDS makes it possible to observe topography surface and morphology samples and examination of chemical components. Physical laboratory of the Institute of Criminalistics Prague use SEM especially for examination of inorganic samples, rarely for biology and other material. Recently, possibilities of electron microscopy have been extended considerably using dual systems with focused ion beam. These systems are applied mainly in study of inner micro and nanoparticles , thin layers (intersecting lines in graphical forensic examinations, analysis of layers of functional glass, etc.), study of alloys microdefects, creating 3D particles and aggregates models, etc. Automated mineralogical analyses are a great asset to analysis of mineral phases, particularly soils, similarly it holds for cathode luminescence, predominantly colour one and precise quantitative measurement of their spectral characteristics. Among latest innovations that are becoming to appear also at ordinary laboratories are TOF - SIMS systems and micro Raman spectroscopy with a resolution comparable to EDS/WDS analysis (capable of achieving similar level as through EDS/WDS analysis).

  6. Illuminating Electron Microscopy of Photocatalysts

    DEFF Research Database (Denmark)

    Cavalca, Filippo

    Photocatalysts are of fundamental interest for sustainable energy research because of their wide range of applications and great potential for state of the art and future usages [1]. By means of Transmission Electron Microscopy (TEM) it is possible to give a deep insight in the structure......, composition and operation of photocatalysts and to provide information on the compounds inner arrangement and a fundamental contribution for their further optimization [2]. We want to construct a novel specimen holder capable of shining light onto samples inside the TEM allowing real time in situ experiments...... an Environmental TEM (ETEM) in order to expose the specimen to a controlled gas atmosphere during illumination. The aim is to perform complete and exhaustive characterization of photocatalytic materials under simulated working environment, achieving experimental data on yet uninvestigated aspects. Analysis can...

  7. Illuminating Electron Microscopy of Photocatalysts

    DEFF Research Database (Denmark)

    Cavalca, Filippo

    Photocatalysts are of fundamental interest for sustainable energy research [1]. By means of transmission electron microscopy (TEM) it is possible to obtain deep insight in the structure, composition and reactivity of photocatalysts for their further optimization [2]. We have constructed a novel...... the device inside an environmental TEM (ETEM) in order to allow specimens to be exposed to controlled gas atmospheres during illumination. The holder is presently being used to study a variety of photoreactive materials and structures, including photocatalysts, photonic devices and solar cells. Here, we...... specimen holder capable of shining light onto samples inside the TEM. The holder contains a laser diode and an optical system that guides light onto a sample with maximum power transmission. The source can be changed and tuned, in principle spanning the whole visible and UV spectrum. It is possible to use...

  8. Correlative Stochastic Optical Reconstruction Microscopy and Electron Microscopy

    Science.gov (United States)

    Kim, Doory; Deerinck, Thomas J.; Sigal, Yaron M.; Babcock, Hazen P.; Ellisman, Mark H.; Zhuang, Xiaowei

    2015-01-01

    Correlative fluorescence light microscopy and electron microscopy allows the imaging of spatial distributions of specific biomolecules in the context of cellular ultrastructure. Recent development of super-resolution fluorescence microscopy allows the location of molecules to be determined with nanometer-scale spatial resolution. However, correlative super-resolution fluorescence microscopy and electron microscopy (EM) still remains challenging because the optimal specimen preparation and imaging conditions for super-resolution fluorescence microscopy and EM are often not compatible. Here, we have developed several experiment protocols for correlative stochastic optical reconstruction microscopy (STORM) and EM methods, both for un-embedded samples by applying EM-specific sample preparations after STORM imaging and for embedded and sectioned samples by optimizing the fluorescence under EM fixation, staining and embedding conditions. We demonstrated these methods using a variety of cellular targets. PMID:25874453

  9. Fast electron microscopy via compressive sensing

    Science.gov (United States)

    Larson, Kurt W; Anderson, Hyrum S; Wheeler, Jason W

    2014-12-09

    Various technologies described herein pertain to compressive sensing electron microscopy. A compressive sensing electron microscope includes a multi-beam generator and a detector. The multi-beam generator emits a sequence of electron patterns over time. Each of the electron patterns can include a plurality of electron beams, where the plurality of electron beams is configured to impart a spatially varying electron density on a sample. Further, the spatially varying electron density varies between each of the electron patterns in the sequence. Moreover, the detector collects signals respectively corresponding to interactions between the sample and each of the electron patterns in the sequence.

  10. Transmission Electron Microscopy Physics of Image Formation

    CERN Document Server

    Kohl, Helmut

    2008-01-01

    Transmission Electron Microscopy: Physics of Image Formation presents the theory of image and contrast formation, and the analytical modes in transmission electron microscopy. The principles of particle and wave optics of electrons are described. Electron-specimen interactions are discussed for evaluating the theory of scattering and phase contrast. Also discussed are the kinematical and dynamical theories of electron diffraction and their applications for crystal-structure analysis and imaging of lattices and their defects. X-ray microanalysis and electron energy-loss spectroscopy are treated as analytical methods. Specimen damage and contamination by electron irradiation limits the resolution for biological and some inorganic specimens. This fifth edition includes discussion of recent progress, especially in the area of aberration correction and energy filtering; moreover, the topics introduced in the fourth edition have been updated. Transmission Electron Microscopy: Physics of Image Formation is written f...

  11. Ultrafast Science Opportunities with Electron Microscopy

    Energy Technology Data Exchange (ETDEWEB)

    DURR, HERMANN; Wang, X.J., ed.

    2016-04-28

    X-rays and electrons are two of the most fundamental probes of matter. When the Linac Coherent Light Source (LCLS), the world’s first x-ray free electron laser, began operation in 2009, it transformed ultrafast science with the ability to generate laser-like x-ray pulses from the manipulation of relativistic electron beams. This document describes a similar future transformation. In Transmission Electron Microscopy, ultrafast relativistic (MeV energy) electron pulses can achieve unsurpassed spatial and temporal resolution. Ultrafast temporal resolution will be the next frontier in electron microscopy and can ideally complement ultrafast x-ray science done with free electron lasers. This document describes the Grand Challenge science opportunities in chemistry, material science, physics and biology that arise from an MeV ultrafast electron diffraction & microscopy facility, especially when coupled with linac-based intense THz and X-ray pump capabilities.

  12. CLAFEM: Correlative light atomic force electron microscopy.

    Science.gov (United States)

    Janel, Sébastien; Werkmeister, Elisabeth; Bongiovanni, Antonino; Lafont, Frank; Barois, Nicolas

    2017-01-01

    Atomic force microscopy (AFM) is becoming increasingly used in the biology field. It can give highly accurate topography and biomechanical quantitative data, such as adhesion, elasticity, and viscosity, on living samples. Nowadays, correlative light electron microscopy is a must-have tool in the biology field that combines different microscopy techniques to spatially and temporally analyze the structure and function of a single sample. Here, we describe the combination of AFM with superresolution light microscopy and electron microscopy. We named this technique correlative light atomic force electron microscopy (CLAFEM) in which AFM can be used on fixed and living cells in association with superresolution light microscopy and further processed for transmission or scanning electron microscopy. We herein illustrate this approach to observe cellular bacterial infection and cytoskeleton. We show that CLAFEM brings complementary information at the cellular level, from on the one hand protein distribution and topography at the nanometer scale and on the other hand elasticity at the piconewton scales to fine ultrastructural details. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. Scanning Electron Microscopy in modern dentistry research

    OpenAIRE

    Paradella, Thaís Cachuté; Unesp-FOSJC; Bottino, Marco Antonio; Unesp-FOSJC

    2012-01-01

    The purpose of this article was to review the usage of Scanning Electron Microscopy (SEM) in dentistry research nowadays, through a careful and updated literature review. By using the key-words Scanning Electron Microscopy and one of the following areas of research in dentistry (Endodontics, Periodontics and Implant), in international database (PubMed), in the year of 2012 (from January to September), a total of 112 articles were found. This data was tabled and the articles were classified ac...

  14. High-energy electron diffraction and microscopy

    CERN Document Server

    Peng, L M; Whelan, M J

    2011-01-01

    This book provides a comprehensive introduction to high energy electron diffraction and elastic and inelastic scattering of high energy electrons, with particular emphasis on applications to modern electron microscopy. Starting from a survey of fundamental phenomena, the authors introduce the most important concepts underlying modern understanding of high energy electron diffraction. Dynamical diffraction in transmission (THEED) and reflection (RHEED) geometries is treated using ageneral matrix theory, where computer programs and worked examples are provided to illustrate the concepts and to f

  15. Scanning electron microscopy of bone.

    Science.gov (United States)

    Boyde, Alan

    2012-01-01

    This chapter described methods for Scanning Electron Microscopical imaging of bone and bone cells. Backscattered electron (BSE) imaging is by far the most useful in the bone field, followed by secondary electrons (SE) and the energy dispersive X-ray (EDX) analytical modes. This chapter considers preparing and imaging samples of unembedded bone having 3D detail in a 3D surface, topography-free, polished or micromilled, resin-embedded block surfaces, and resin casts of space in bone matrix. The chapter considers methods for fixation, drying, looking at undersides of bone cells, and coating. Maceration with alkaline bacterial pronase, hypochlorite, hydrogen peroxide, and sodium or potassium hydroxide to remove cells and unmineralised matrix is described in detail. Attention is given especially to methods for 3D BSE SEM imaging of bone samples and recommendations for the types of resin embedding of bone for BSE imaging are given. Correlated confocal and SEM imaging of PMMA-embedded bone requires the use of glycerol to coverslip. Cathodoluminescence (CL) mode SEM imaging is an alternative for visualising fluorescent mineralising front labels such as calcein and tetracyclines. Making spatial casts from PMMA or other resin embedded samples is an important use of this material. Correlation with other imaging means, including microradiography and microtomography is important. Shipping wet bone samples between labs is best done in glycerol. Environmental SEM (ESEM, controlled vacuum mode) is valuable in eliminating -"charging" problems which are common with complex, cancellous bone samples.

  16. Electron microscopy of Paramecium (Ciliata).

    Science.gov (United States)

    Hausmann, Klaus; Allen, Richard D

    2010-01-01

    Paramecium may be the best known single-celled organism in existence (Hausmann et al., 2003). Today its image often appears on television programs where the producers use it to illustrate a stereotypic microorganism, be it pathogenic or nonpathogenic, prokaryotic or eukaryotic. Paramecium was probably one of the first single-celled organisms observed with a light microscope by the Dutch cloth vendor and amateur lens maker Antoni van Leuwenhoek (1632-1723) (Dobell, 1932), and it is still being investigated in the 21st century in the days of the modern electron microscopes. Copyright © 2010 Elsevier Inc. All rights reserved.

  17. Ultrathin sectioning for electron microscopy

    DEFF Research Database (Denmark)

    Rostgaard, Jørgen; Qvortrup, K

    1989-01-01

    During an electron microscopical study of the localization of the nucleoside diphosphatase IDPase in Reissner's membrane of the inner ear, it was discovered that the distilled water in the knife trough produced an annoying artefact. It dissolved all the lead phosphate reaction product from...... the sections, and thus converted a positive phosphatase reactivity to a false negative one. The water in the knife trough had a pH of approximately 5.4. Calculations showed that this is an expected acidity, if CO2 in the air equilibrates with distilled water, and that there is 200,000 times more acid...

  18. Thermal diffuse scattering in transmission electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Forbes, B.D.; D' Alfonso, A.J. [School of Physics, University of Melbourne, Parkville, Victoria 3010 (Australia); Findlay, S.D. [School of Physics, Monash University, Victoria 3800 (Australia); Van Dyck, D. [EMAT, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium); LeBeau, J.M. [North Carolina State University, Raleigh, NC 27695-7907 (United States); Stemmer, S. [Materials Department, University of California, Santa Barbara, CA 93106-5050 (United States); Allen, L.J., E-mail: lja@unimelb.edu.au [School of Physics, University of Melbourne, Parkville, Victoria 3010 (Australia)

    2011-12-15

    In conventional transmission electron microscopy, thermal scattering significantly affects the image contrast. It has been suggested that not accounting for this correctly is the main cause of the Stobbs factor, the ubiquitous, large contrast mismatch found between theory and experiment. In the case where a hard aperture is applied, we show that previous conclusions drawn from work using bright field scanning transmission electron microscopy and invoking the principle of reciprocity are reliable in the presence of thermal scattering. In the aperture-free case it has been suggested that even the most sophisticated mathematical models for thermal diffuse scattering lack in their numerical implementation, specifically that there may be issues in sampling, including that of the contrast transfer function of the objective lens. We show that these concerns can be satisfactorily overcome with modest computing resources; thermal scattering can be modelled accurately enough for the purpose of making quantitative comparison between simulation and experiment. Spatial incoherence of the source is also investigated. Neglect or inadequate handling of thermal scattering in simulation can have an appreciable effect on the predicted contrast and can be a significant contribution to the Stobbs factor problem. -- Highlights: Black-Right-Pointing-Pointer We determine the numerical requirements for accurate simulation of TDS in CTEM. Black-Right-Pointing-Pointer TDS can be simulated to high precision using the Born-Oppenheimer model. Black-Right-Pointing-Pointer Such calculations establish the contribution of TDS to the Stobbs factor problem. Black-Right-Pointing-Pointer Treating spatial incoherence using envelope functions increases image contrast. Black-Right-Pointing-Pointer Rigorous treatment of spatial incoherence significantly reduces image contrast.

  19. Cryo-electron microscopy of vitreous sections.

    Science.gov (United States)

    Chlanda, Petr; Sachse, Martin

    2014-01-01

    More than 30 years ago two groups independently reported the vitrification of pure water, which was until then regarded as impossible without a cryoprotectant [1, 2]. This opened the opportunity to cryo-electron microscopy (cryo-EM) to observe biological samples at nanometer scale, close to their native state. However, poor electron penetration through biological samples sets the limit for sample thickness to less than the average size of the mammalian cell. In order to image bulky specimens at the cell or tissue level in transmission electron microscopy (TEM), a sample has to be either thinned by focused ion beam or mechanically sectioned. The latter technique, Cryo-Electron Microscopy of Vitreous Section (CEMOVIS), employs cryo-ultramicrotomy to produce sections with thicknesses of 40-100 μm of vitreous biological material suitable for cryo-EM. CEMOVIS consists of trimming and sectioning a sample with a diamond knife, placing and attaching the section onto an electron microscopy grid, transferring the grid to the cryo-electron microscope and imaging. All steps must be carried on below devitrification temperature to obtain successful results. In this chapter we provide a step-by-step guide to produce and image vitreous sections of a biological sample.

  20. [Synovial fluid crystal identification by electron microscopy].

    Science.gov (United States)

    Nero, Patrícia; Nogueira, Isabel; Vilar, Rui; Pimentão, J Bravo; Branco, Jaime C

    2006-01-01

    In clinical practice crystal identification in synovial fluid is made by polarized light microscopy and with some specific stainings. Nevertheless, sometimes we are unable to identify crystals by these means, either because they are too small or because they are widespread on the fluid. To compare the identification of crystals in synovial fluid from patients with non-infectious monoarthritis but no history of local trauma or articular disease, using polarized light and electronic microscopy. We analized synovial fluid samples from patients with non-infectious monoarthritis and no history of local trauma or articular disease. First we used a polarized light microscope and alizarin red staining. Later we used conventional transmission electron microscopy and energy dispersive spectroscopy, in order to identify and characterize crystals. Fourty-five samples from 23 synovial fluids were analyzed. Under polarized light microscopy we identified crystals on 11 samples: 3 with calcium pyrophosphate crystals, 6 with calcium basic phosphate crystals and 2 with sodium monourate crystals. On the remaining 12 samples we were unable to identify crystals. Samples were then analyzed by conventional transmission electron microscopy and energy dispersive spectroscopy confirming the presence of the previously identified crystals. On the remainig 12 samples we were able to identify calcium basic phosphate crystals. Microcrystals seem to be an universal finding in synovial fluid of patients with osteoarthritis. The prevention of their deposition in joints might contribute to stop joint damage in this disease.

  1. Aberration corrected Lorentz scanning transmission electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    McVitie, S., E-mail: stephen.mcvitie@glasgow.ac.uk; McGrouther, D.; McFadzean, S.; MacLaren, D.A.; O’Shea, K.J.; Benitez, M.J.

    2015-05-15

    We present results from an aberration corrected scanning transmission electron microscope which has been customised for high resolution quantitative Lorentz microscopy with the sample located in a magnetic field free or low field environment. We discuss the innovations in microscope instrumentation and additional hardware that underpin the imaging improvements in resolution and detection with a focus on developments in differential phase contrast microscopy. Examples from materials possessing nanometre scale variations in magnetisation illustrate the potential for aberration corrected Lorentz imaging as a tool to further our understanding of magnetism on this lengthscale. - Highlights: • Demonstration of nanometre scale resolution in magnetic field free environment using aberration correction in the scanning transmission electron microscope (STEM). • Implementation of differential phase contrast mode of Lorentz microscopy in aberration corrected STEM with improved sensitivity. • Quantitative imaging of magnetic induction of nanostructures in amorphous and cross-section samples.

  2. Transmission electron microscopy characterization of nanomaterials

    CERN Document Server

    2014-01-01

    Third volume of a 40volume series on nanoscience and nanotechnology, edited by the renowned scientist Challa S.S.R. Kumar. This handbook gives a comprehensive overview about Transmission electron microscopy characterization of nanomaterials. Modern applications and state-of-the-art techniques are covered and make this volume an essential reading for research scientists in academia and industry.

  3. Scanning electron microscopy study of Trichomonas gallinae.

    Science.gov (United States)

    Tasca, Tiana; De Carli, Geraldo A

    2003-12-01

    A scanning electron microscopy (SEM) study of Trichomonas gallinae (Rivolta, 1878), provided more information about the morphology of this flagellated protozoan. SEM showed the morphological features of the trophozoites; the emergence of the anterior flagella, the structure of the undulating membrane, the position and shape of the pelta, axostyle and posterior flagellum. Of special interest were the pseudocyst forms.

  4. Conventional electron microscopy, cryo-electron microscopy and cryo-electron tomography of viruses.

    Science.gov (United States)

    Castón, José R

    2013-01-01

    Electron microscopy (EM) techniques have been crucial for understanding the structure of biological specimens such as cells, tissues and macromolecular assemblies. Viruses and related viral assemblies are ideal targets for structural studies that help to define essential biological functions. Whereas conventional EM methods use chemical fixation, dehydration, and staining of the specimens, cryo-electron microscopy (cryo-EM) preserves the native hydrated state. Combined with image processing and three-dimensional reconstruction techniques, cryo-EM provides 3D maps of these macromolecular complexes from projection images, at subnanometer to near-atomic resolutions. Cryo-EM is also a major technique in structural biology for dynamic studies of functional complexes, which are often unstable, flexible, scarce or transient in their native environments. As a tool, cryo-EM complements high-resolution techniques such as X-ray diffraction and NMR spectroscopy; these synergistic hybrid approaches provide important new information. Three-dimensional cryo-electron tomography goes further, and allows the study of viruses not only in their physiological state, but also in their natural environment in the cell, thereby bridging structural studies at the molecular and cellular levels.

  5. 4D electron microscopy: principles and applications.

    Science.gov (United States)

    Flannigan, David J; Zewail, Ahmed H

    2012-10-16

    The transmission electron microscope (TEM) is a powerful tool enabling the visualization of atoms with length scales smaller than the Bohr radius at a factor of only 20 larger than the relativistic electron wavelength of 2.5 pm at 200 keV. The ability to visualize matter at these scales in a TEM is largely due to the efforts made in correcting for the imperfections in the lens systems which introduce aberrations and ultimately limit the achievable spatial resolution. In addition to the progress made in increasing the spatial resolution, the TEM has become an all-in-one characterization tool. Indeed, most of the properties of a material can be directly mapped in the TEM, including the composition, structure, bonding, morphology, and defects. The scope of applications spans essentially all of the physical sciences and includes biology. Until recently, however, high resolution visualization of structural changes occurring on sub-millisecond time scales was not possible. In order to reach the ultrashort temporal domain within which fundamental atomic motions take place, while simultaneously retaining high spatial resolution, an entirely new approach from that of millisecond-limited TEM cameras had to be conceived. As shown below, the approach is also different from that of nanosecond-limited TEM, whose resolution cannot offer the ultrafast regimes of dynamics. For this reason "ultrafast electron microscopy" is reserved for the field which is concerned with femtosecond to picosecond resolution capability of structural dynamics. In conventional TEMs, electrons are produced by heating a source or by applying a strong extraction field. Both methods result in the stochastic emission of electrons, with no control over temporal spacing or relative arrival time at the specimen. The timing issue can be overcome by exploiting the photoelectric effect and using pulsed lasers to generate precisely timed electron packets of ultrashort duration. The spatial and temporal resolutions

  6. Introduction to Conventional Transmission Electron Microscopy

    Science.gov (United States)

    de Graef, Marc

    2003-04-01

    This book covers the fundamentals of conventional transmission electron microscopy (CTEM) as applied to crystalline solids. In addition to including a large selection of worked examples and homework problems, the volume is accompanied by a supplementary website (http://ctem.web.cmu.edu/) containing interactive modules and over 30,000 lines of free Fortran 90 source code. The work is based on a lecture course given by Marc De Graef in the Department of Materials Science and Engineering at Carnegie Mellon University.

  7. Biological cryo‐electron microscopy in China

    Science.gov (United States)

    2016-01-01

    Abstract Cryo‐electron microscopy (cryo‐EM) plays an increasingly more important role in structural biology. With the construction of an arm of the Chinese National Protein Science Facility at Tsinghua University, biological cryo‐EM has entered a phase of rapid development in China. This article briefly reviews the history of biological cryo‐EM in China, describes its current status, comments on its impact on the various biological research fields, and presents future outlook. PMID:27534377

  8. Biological cryo?electron microscopy in China

    OpenAIRE

    Wang, Hong Wei; Lei, Jianlin; Shi, Yigong

    2016-01-01

    Abstract Cryo?electron microscopy (cryo?EM) plays an increasingly more important role in structural biology. With the construction of an arm of the Chinese National Protein Science Facility at Tsinghua University, biological cryo?EM has entered a phase of rapid development in China. This article briefly reviews the history of biological cryo?EM in China, describes its current status, comments on its impact on the various biological research fields, and presents future outlook.

  9. Scanning electron microscopy of superficial white onychomycosis*

    Science.gov (United States)

    de Almeida Jr., Hiram Larangeira; Boabaid, Roberta Oliveira; Timm, Vitor; Silva, Ricardo Marques e; de Castro, Luis Antonio Suita

    2015-01-01

    Superficial white onychomycosis is characterized by opaque, friable, whitish superficial spots on the nail plate. We examined an affected halux nail of a 20-year-old male patient with scanning electron microscopy. The mycological examination isolated Trichophyton mentagrophytes. Abundant hyphae with the formation of arthrospores were found on the nail's surface, forming small fungal colonies. These findings showed the great capacity for dissemination of this form of onychomycosis. PMID:26560225

  10. Scanning electron microscopy of molluscum contagiosum*

    OpenAIRE

    Almeida Jr,Hiram Larangeira de; Abuchaim,Martha Oliveira; Schneide, Maiko Abel; Marques, Leandra; Castro, Luis Antônio Suíta de

    2013-01-01

    Molluscum contagiosum is a disease caused by a poxvirus. It is more prevalent in children up to 5 years of age. There is a second peak of incidence in young adults. In order to examine its ultrastructure, three lesions were curetted without disruption, cut transversely with a scalpel, and routinely processed for scanning electron microscopy (SEM). The oval structure of molluscum contagiosum could be easily identified. In its core, there was a central umbilication and just below this depressio...

  11. Scanning electron microscopy of cold gases

    Science.gov (United States)

    Santra, Bodhaditya; Ott, Herwig

    2015-06-01

    Ultracold quantum gases offer unique possibilities to study interacting many-body quantum systems. Probing and manipulating such systems with ever increasing degree of control requires novel experimental techniques. Scanning electron microscopy is a high resolution technique which can be used for in situ imaging, single site addressing in optical lattices and precision density engineering. Here, we review recent advances and achievements obtained with this technique and discuss future perspectives.

  12. Transmission electron microscopy in micro-nanoelectronics

    CERN Document Server

    Claverie, Alain

    2013-01-01

    Today, the availability of bright and highly coherent electron sources and sensitive detectors has radically changed the type and quality of the information which can be obtained by transmission electron microscopy (TEM). TEMs are now present in large numbers not only in academia, but also in industrial research centers and fabs.This book presents in a simple and practical way the new quantitative techniques based on TEM which have recently been invented or developed to address most of the main challenging issues scientists and process engineers have to face to develop or optimize sem

  13. Transmission Electron Microscopy and Diffractometry of Materials

    CERN Document Server

    Fultz, Brent

    2013-01-01

    This book explains concepts of transmission electron microscopy (TEM) and x-ray diffractometry (XRD) that are important for the characterization of materials. The fourth edition adds important new techniques of TEM such as electron tomography, nanobeam diffraction, and geometric phase analysis. A new chapter on neutron scattering completes the trio of x-ray, electron and neutron diffraction. All chapters were updated and revised for clarity. The book explains the fundamentals of how waves and wavefunctions interact with atoms in solids, and the similarities and differences of using x-rays, electrons, or neutrons for diffraction measurements. Diffraction effects of crystalline order, defects, and disorder in materials are explained in detail. Both practical and theoretical issues are covered. The book can be used in an introductory-level or advanced-level course, since sections are identified by difficulty. Each chapter includes a set of problems to illustrate principles, and the extensive Appendix includes la...

  14. Phase-contrast scanning transmission electron microscopy.

    Science.gov (United States)

    Minoda, Hiroki; Tamai, Takayuki; Iijima, Hirofumi; Hosokawa, Fumio; Kondo, Yukihito

    2015-06-01

    This report introduces the first results obtained using phase-contrast scanning transmission electron microscopy (P-STEM). A carbon-film phase plate (PP) with a small center hole is placed in the condenser aperture plane so that a phase shift is introduced in the incident electron waves except those passing through the center hole. A cosine-type phase-contrast transfer function emerges when the phase-shifted scattered waves interfere with the non-phase-shifted unscattered waves, which passed through the center hole before incidence onto the specimen. The phase contrast resulting in P-STEM is optically identical to that in phase-contrast transmission electron microscopy that is used to provide high contrast for weak phase objects. Therefore, the use of PPs can enhance the phase contrast of the STEM images of specimens in principle. The phase shift resulting from the PP, whose thickness corresponds to a phase shift of π, has been confirmed using interference fringes displayed in the Ronchigram of a silicon single crystal specimen. The interference fringes were found to abruptly shift at the edge of the PP hole by π. © The Author 2015. 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.

  15. Transmission Electron Microscopy of Minerals and Rocks

    Science.gov (United States)

    McLaren, Alex C.

    1991-04-01

    Of the many techniques that have been applied to the study of crystal defects, none has contributed more to our understanding of their nature and influence on the physical and chemical properties of crystalline materials than transmission electron microscopy (TEM). TEM is now used extensively by an increasing number of earth scientists for direct observation of defect microstructures in minerals and rocks. Transmission Electron Microscopy of Rocks and Minerals is an introduction to the principles of the technique and is the only book to date on the subject written specifically for geologists and mineralogists. The first part of the book deals with the essential physics of the transmission electron microscope and presents the basic theoretical background required for the interpretation of images and electron diffraction patterns. The final chapters are concerned with specific applications of TEM in mineralogy and deal with such topics as planar defects, intergrowths, radiation-induced defects, dislocations and deformation-induced microstructures. The examples cover a wide range of rock-forming minerals from crustal rocks to those in the lower mantle, and also take into account the role of defects in important mineralogical and geological processes.

  16. Biological cryo-electron microscopy in China.

    Science.gov (United States)

    Wang, Hong-Wei; Lei, Jianlin; Shi, Yigong

    2017-01-01

    Cryo-electron microscopy (cryo-EM) plays an increasingly more important role in structural biology. With the construction of an arm of the Chinese National Protein Science Facility at Tsinghua University, biological cryo-EM has entered a phase of rapid development in China. This article briefly reviews the history of biological cryo-EM in China, describes its current status, comments on its impact on the various biological research fields, and presents future outlook. © 2016 The Authors Protein Science published by Wiley Periodicals, Inc. on behalf of The Protein Society.

  17. Cryo-electron microscopy of chromatin biology.

    Science.gov (United States)

    Wilson, Marcus D; Costa, Alessandro

    2017-06-01

    The basic unit of chromatin, the nucleosome core particle (NCP), controls how DNA in eukaryotic cells is compacted, replicated and read. Since its discovery, biochemists have sought to understand how this protein-DNA complex can help to control so many diverse tasks. Recent electron-microscopy (EM) studies on NCP-containing assemblies have helped to describe important chromatin transactions at a molecular level. With the implementation of recent technical advances in single-particle EM, our understanding of how nucleosomes are recognized and read looks to take a leap forward. In this review, the authors highlight recent advances in the architectural understanding of chromatin biology elucidated by EM.

  18. Attomicroscopy: from femtosecond to attosecond electron microscopy

    Science.gov (United States)

    Hassan, Mohammed Th

    2018-02-01

    In the last decade, the development of ultrafast electron diffraction (UED) and microscopy (UEM) have enabled the imaging of atomic motion in real time and space. These pivotal table-top tools opened the door for a vast range of applications in different areas of science spanning chemistry, physics, materials science, and biology. We first discuss the basic principles and recent advancements, including some of the important applications, of both UED and UEM. Then, we discuss the recent advances in the field that have enhanced the spatial and temporal resolutions, where the latter, is however, still limited to a few hundreds of femtoseconds, preventing the imaging of ultrafast dynamics of matter lasting few tens of femtoseconds. Then, we present our new optical gating approach for generating an isolated 30 fs electron pulse with sufficient intensity to attain a temporal resolution on the same time scale. This achievement allows, for the first time, imaging the electron dynamics of matter. Finally, we demonstrate the feasibility of the optical gating approach to generate an isolated attosecond electron pulse, utilizing our recently demonstrated optical attosecond laser pulse, which paves the way for establishing the field of ‘Attomicroscopy’, ultimately enabling us to image the electron motion in action.

  19. Standard transition aluminas. Electron microscopy studies

    Directory of Open Access Journals (Sweden)

    Santos P. Souza

    2000-01-01

    Full Text Available The aim of this paper is to present the results of characterization of the particle shapes of six standard transition aluminas samples using transmission and scanning electron microscopies; selected area electron diffraction, in parallel with X-ray powder diffraction were used for confirmation of the different transition aluminas types. The transition aluminas - chi; kappa; gamma; theta; delta; and eta were supplied by ALCOA Central Laboratory. The chi-; kappa-;gamma- and delta-Al(20(3 microcrystals are pseudomorphs from their respective precursors gibbsite and boehmite. However, theta-Al(20(3 microcrystals are not pseudomorphs after the standard delta-Al(20(3 sample. Also, eta-Al(20(3 are not pseudomorphs after bayerite somatoids.

  20. An electron microscopy appraisal of tensile fracture in metallic glasses

    NARCIS (Netherlands)

    Matthews, D. T. A.; Ocelik, V.; Bronsveld, P. M.; De Hosson, J. Th. M.

    Three glass-forming alloy compositions were chosen for ribbon production and subsequent electron microscopy studies. In situ tensile testing with transmission electron microscopy (TEM), followed by ex situ TEM and ex situ scanning electron microscopy (SEM), allowed the deformation processes in

  1. Electron microscopy study of refractory ceramic fibers.

    Science.gov (United States)

    MacKinnon, P A; Lentz, T J; Rice, C H; Lockey, J E; Lemasters, G K; Gartside, P S

    2001-10-01

    In epidemiological studies designed to identify potential health risks of exposures to synthetic vitreous fibers, the characterization of airborne fiber dimensions may be essential for assessing mechanisms of fiber toxicity. Toward this end, air sampling was conducted as part of an industry-wide study of workers potentially exposed to airborne fibrous dusts during the manufacture of refractory ceramic fibers (RCF) and RCF products. Analyses of a subset of samples obtained on the sample filter as well as on the conductive sampling cowl were performed using both scanning electron microscopy (SEM) and transmission electron microscopy (TEM) to characterize dimensions of airborne fibers. Comparison was made of bivariate fiber size distributions (length and diameter) from air samples analyzed by SEM and by TEM techniques. Results of the analyses indicate that RCF size distributions include fibers small enough in diameter (fibers (> 60 microm) may go undetected by TEM, as evidenced by the proportion of fibers in this category for TEM and SEM analyses (1% and 5%, respectively). Limitations of the microscopic techniques and differences in fiber-sizing rules for each method are believed to have contributed to the variation among fiber-sizing results. It was concluded from these data that further attempts to characterize RCF exposure in manufacturing and related operations should include analysis by TEM and SEM, since the smallest diameter fibers are not resolved with SEM and the fibers of longer length are not sized by TEM.

  2. Characterization of nanomaterials with transmission electron microscopy

    KAUST Repository

    Anjum, Dalaver H.

    2016-08-01

    The field of nanotechnology is about research and development on materials whose at least one dimension is in the range of 1 to 100 nanometers. In recent years, the research activity for developing nano-materials has grown exponentially owing to the fact that they offer better solutions to the challenges faced by various fields such as energy, food, and environment. In this paper, the importance of transmission electron microscopy (TEM) based techniques is demonstrated for investigating the properties of nano-materials. Specifically the nano-materials that are investigated in this report include gold nano-particles (Au-NPs), silver atom-clusters (Ag-ACs), tantalum single-atoms (Ta-SAs), carbon materials functionalized with iron cobalt (Fe-Co) NPs and titania (TiO2) NPs, and platinum loaded Ceria (Pt-CeO2) Nano composite. TEM techniques that are employed to investigate nano-materials include aberration corrected bright-field TEM (BF-TEM), high-angle dark-field scanning TEM (HAADF-STEM), electron energy-loss spectroscopy (EELS), and BF-TEM electron tomography (ET). With the help presented of results in this report, it is proved herein that as many TEM techniques as available in a given instrument are essential for a comprehensive nano-scale analysis of nanomaterials.

  3. Scanning electron microscopy of molluscum contagiosum*

    Science.gov (United States)

    de Almeida Jr, Hiram Larangeira; Abuchaim, Martha Oliveira; Schneider, Maiko Abel; Marques, Leandra; de Castro, Luis Antônio Suíta

    2013-01-01

    Molluscum contagiosum is a disease caused by a poxvirus. It is more prevalent in children up to 5 years of age. There is a second peak of incidence in young adults. In order to examine its ultrastructure, three lesions were curetted without disruption, cut transversely with a scalpel, and routinely processed for scanning electron microscopy (SEM). The oval structure of molluscum contagiosum could be easily identified. In its core, there was a central umbilication and just below this depression, there was a keratinized tunnel. Under higher magnification, a proliferation similar to the epidermis was seen. Moreover, there were areas of cells disposed like a mosaic. Under higher magnification, rounded structures measuring 0.4 micron could be observed at the end of the keratinized tunnel and on the surface of the lesion. PMID:23539009

  4. Transmission electron microscopy and diffractometry of materials

    CERN Document Server

    Fultz, Brent

    2001-01-01

    This book teaches graduate students the concepts of trans- mission electron microscopy (TEM) and x-ray diffractometry (XRD) that are important for the characterization of materi- als. It emphasizes themes common to both techniques, such as scattering from atoms and the formation and analysis of dif- fraction patterns. It also describes unique aspects of each technique, especially imaging and spectroscopy in the TEM. The textbook thoroughly develops both introductory and ad- vanced-level material, using over 400 accompanying illustra- tions. Problems are provided at the end of each chapter to reinforce key concepts. Simple citatioins of rules are avoi- ded as much as possible, and both practical and theoretical issues are explained in detail. The book can be used as both an introductory and advanced-level graduate text since sec- tions/chapters are sorted according to difficulty and grou- ped for use in quarter and semester courses on TEM and XRD.

  5. Improved methods for high resolution electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, J.R.

    1987-04-01

    Existing methods of making support films for high resolution transmission electron microscopy are investigated and novel methods are developed. Existing methods of fabricating fenestrated, metal reinforced specimen supports (microgrids) are evaluated for their potential to reduce beam induced movement of monolamellar crystals of C/sub 44/H/sub 90/ paraffin supported on thin carbon films. Improved methods of producing hydrophobic carbon films by vacuum evaporation, and improved methods of depositing well ordered monolamellar paraffin crystals on carbon films are developed. A novel technique for vacuum evaporation of metals is described which is used to reinforce microgrids. A technique is also developed to bond thin carbon films to microgrids with a polymer bonding agent. Unique biochemical methods are described to accomplish site specific covalent modification of membrane proteins. Protocols are given which covalently convert the carboxy terminus of papain cleaved bacteriorhodopsin to a free thiol. 53 refs., 19 figs., 1 tab.

  6. Transmission Electron Microscopy Characterization of Nanocrystalline Copper

    Energy Technology Data Exchange (ETDEWEB)

    Kung, H.; Sanders, P.G.; Weertman, J.R.

    1999-11-01

    The microstructure and grain boundary structure of nanocrystalline Cu powders and a compact prepared by the inert-gas condensation technique have been characterized by transmission electron microscopy. The as-prepared particles are round in shape and have no distinct surface facets. Annealing twins (coherent {Sigma}3 boundaries) have been observed in the as-prepared Cu particles as well as in the compact. Pores are commonly found at grain boundaries, triple grain junctions and some in the interior of grains in the compact. In addition to twin boundaries, a number of special grain boundaries have been observed. These special grain boundaries have low-index interface planes, and sometimes have misorientation angles close to coincidence site lattice (CSL) orientations.

  7. Correlative light and electron microscopy : strategies and applications

    NARCIS (Netherlands)

    Driel, Linda Francina van

    2011-01-01

    Correlative light and electron microscopy (CLEM) refers to the observation of the same structures or ultrastructures with both light microscopy (LM) and electron microscopy (EM). LM provides an overview of the studied material, and enables the quick localization of structures that are fluorescently

  8. Analyzing Lysosome-Related Organelles by Electron Microscopy

    KAUST Repository

    Hurbain, Ilse

    2017-04-29

    Intracellular organelles have a particular morphological signature that can only be appreciated by ultrastructural analysis at the electron microscopy level. Optical imaging and associated methodologies allow to explore organelle localization and their dynamics at the cellular level. Deciphering the biogenesis and functions of lysosomes and lysosome-related organelles (LROs) and their dysfunctions requires their visualization and detailed characterization at high resolution by electron microscopy. Here, we provide detailed protocols for studying LROs by transmission electron microscopy. While conventional electron microscopy and its recent improvements is the method of choice to investigate organelle morphology, immunoelectron microscopy allows to localize organelle components and description of their molecular make up qualitatively and quantitatively.

  9. The role of electron microscopy for the diagnosis of glomerulopathies

    Directory of Open Access Journals (Sweden)

    Angelo Sementilli

    Full Text Available CONTEXT: Electron microscopy has been used for the morphological diagnosis of glomerular diseases for more than three decades and its value has been widely emphasized. However, recent reports have analyzed the routine use of electron microscopy critically. Its use in other areas of diagnosis such as tumor diseases has declined considerably; in addition, in view of the unavoidable financial pressure for the reduction of costs due to investigations and diagnostic routines, the selection of cases for electron microscopy has been quite rigorous. OBJECTIVE: To identify the glomerular diseases that depend on electron microscopy for a final diagnosis, by means of reviewing renal biopsies performed over a 12-year period. DESIGN: Prospective SETTING: Hospital Ana Costa, Hospital Guilherme Álvaro and Serviço de Anatomia Patológica de Santos, Santos, São Paulo, Brazil. PARTICIPANTS: 200 consecutive renal biopsies obtained from private hospitals and the teaching hospital from 1979 to 1991 were studied. MAIN MEASUREMENTS: All cases were analyzed via light microscopy, immunofluorescence and electron microscopy. The diagnosis was first made via light microscopy plus immunofluorescence and then via electron microscopy. RESULTS: Electron microscopy was diagnostic or essential for diagnosis in 10.0% of the cases, corresponding to 3.4% of primary glomerulopathies and 100% of hereditary glomerulopathies. Electron microscopy was contributory (useful to the diagnosis in 5.5% of the cases, confirming the preliminary diagnosis formulated on the basis of clinical and laboratory data and light microscopy plus immunofluorescence findings. We obtained a 7.5% rate of discordant immunofluorescence, which was considered as such when negative immunofluorescence findings were not confirmed by electron microscopy. The final diagnosis with the use of light microscopy plus immunofluorescence alone was 77.0%. CONCLUSIONS: It was possible to diagnose with certainty a great

  10. Simplifying Electron Beam Channeling in Scanning Transmission Electron Microscopy (STEM).

    Science.gov (United States)

    Wu, Ryan J; Mittal, Anudha; Odlyzko, Michael L; Mkhoyan, K Andre

    2017-08-01

    Sub-angstrom scanning transmission electron microscopy (STEM) allows quantitative column-by-column analysis of crystalline specimens via annular dark-field images. The intensity of electrons scattered from a particular location in an atomic column depends on the intensity of the electron probe at that location. Electron beam channeling causes oscillations in the STEM probe intensity during specimen propagation, which leads to differences in the beam intensity incident at different depths. Understanding the parameters that control this complex behavior is critical for interpreting experimental STEM results. In this work, theoretical analysis of the STEM probe intensity reveals that intensity oscillations during specimen propagation are regulated by changes in the beam's angular distribution. Three distinct regimes of channeling behavior are observed: the high-atomic-number (Z) regime, in which atomic scattering leads to significant angular redistribution of the beam; the low-Z regime, in which the probe's initial angular distribution controls intensity oscillations; and the intermediate-Z regime, in which the behavior is mixed. These contrasting regimes are shown to exist for a wide range of probe parameters. These results provide a new understanding of the occurrence and consequences of channeling phenomena and conditions under which their influence is strengthened or weakened by characteristics of the electron probe and sample.

  11. Metal particles in a ceramic matrix--scanning electron microscopy and transmission electron microscopy characterization.

    Science.gov (United States)

    Konopka, K

    2006-09-01

    This paper is concerned with ceramic matrix (Al(2)O(3)) composites with introduced metal particles (Ni, Fe). The composites were obtained via sintering of powders under very high pressure (2.5 GPa). Scanning electron microscopy and transmission electron microscopy were chosen as the tools for the identification and description of the shape, size and distribution of the metal particles. The Al(2)O(3)-Ni composite contained agglomerates of the Ni particles surrounded by ceramic grains and nanometre-size Ni particles located inside the ceramic grains and at the ceramic grain boundaries. In the Al(2)O(3)-Fe composite, the Fe particles were mostly surrounded by ceramic grains. Moreover, holes left by the Fe particles were found. The high pressure used in the fabrication of the composites changed the shape of the metal and ceramic powder grains via plastic deformation.

  12. Electron microscopy: Ultrastable gold substrates for electron cryomicroscopy.

    Science.gov (United States)

    Russo, Christopher J; Passmore, Lori A

    2014-12-12

    Despite recent advances, the structures of many proteins cannot be determined by electron cryomicroscopy because the individual proteins move during irradiation. This blurs the images so that they cannot be aligned with each other to calculate a three-dimensional density. Much of this movement stems from instabilities in the carbon substrates used to support frozen samples in the microscope. Here we demonstrate a gold specimen support that nearly eliminates substrate motion during irradiation. This increases the subnanometer image contrast such that α helices of individual proteins are resolved. With this improvement, we determine the structure of apoferritin, a smooth octahedral shell of α-helical subunits that is particularly difficult to solve by electron microscopy. This advance in substrate design will enable the solution of currently intractable protein structures. Copyright © 2014, American Association for the Advancement of Science.

  13. Image restoration in cryo-electron microscopy.

    Science.gov (United States)

    Penczek, Pawel A

    2010-01-01

    Image restoration techniques are used to obtain, given experimental measurements, the best possible approximation of the original object within the limits imposed by instrumental conditions and noise level in the data. In molecular electron microscopy (EM), we are mainly interested in linear methods that preserve the respective relationships between mass densities within the restored map. Here, we describe the methodology of image restoration in structural EM, and more specifically, we will focus on the problem of the optimum recovery of Fourier amplitudes given electron microscope data collected under various defocus settings. We discuss in detail two classes of commonly used linear methods, the first of which consists of methods based on pseudoinverse restoration, and which is further subdivided into mean-square error, chi-square error, and constrained based restorations, where the methods in the latter two subclasses explicitly incorporates non-white distribution of noise in the data. The second class of methods is based on the Wiener filtration approach. We show that the Wiener filter-based methodology can be used to obtain a solution to the problem of amplitude correction (or "sharpening") of the EM map that makes it visually comparable to maps determined by X-ray crystallography, and thus amenable to comparative interpretation. Finally, we present a semiheuristic Wiener filter-based solution to the problem of image restoration given sets of heterogeneous solutions. We conclude the chapter with a discussion of image restoration protocols implemented in commonly used single particle software packages. Copyright © 2010 Elsevier Inc. All rights reserved.

  14. Imaging Cytoskeleton Components by Electron Microscopy.

    Science.gov (United States)

    Svitkina, Tatyana

    2016-01-01

    The cytoskeleton is a complex of detergent-insoluble components of the cytoplasm playing critical roles in cell motility, shape generation, and mechanical properties of a cell. Fibrillar polymers-actin filaments, microtubules, and intermediate filaments-are major constituents of the cytoskeleton, which constantly change their organization during cellular activities. The actin cytoskeleton is especially polymorphic, as actin filaments can form multiple higher order assemblies performing different functions. Structural information about cytoskeleton organization is critical for understanding its functions and mechanisms underlying various forms of cellular activity. Because of the nanometer-scale thickness of cytoskeletal fibers, electron microscopy (EM) is a key tool to determine the structure of the cytoskeleton. This article describes application of rotary shadowing (or metal replica) EM for visualization of the cytoskeleton. The procedure is applicable to thin cultured cells growing on glass coverslips and consists of detergent extraction of cells to expose their cytoskeleton, chemical fixation to provide stability, ethanol dehydration and critical point drying to preserve three-dimensionality, rotary shadowing with platinum to create contrast, and carbon coating to stabilize replicas. This technique provides easily interpretable three-dimensional images, in which individual cytoskeletal fibers are clearly resolved, and individual proteins can be identified by immunogold labeling. More importantly, replica EM is easily compatible with live cell imaging, so that one can correlate the dynamics of a cell or its components, e.g., expressed fluorescent proteins, with high resolution structural organization of the cytoskeleton in the same cell.

  15. Advanced analytical electron microscopy for lithium-ion batteries

    National Research Council Canada - National Science Library

    Danna Qian; Cheng Ma; Karren L More; Ying Shirley Meng; Miaofang Chi

    2015-01-01

    ... and their synergistic behaviors during battery operation. With the capability of resolving the structure and chemistry at an atomic resolution, advanced analytical transmission electron microscopy (AEM...

  16. 3D correlative light and electron microscopy of cultured cells using serial blockface scanning electron microscopy

    Science.gov (United States)

    Lerner, Thomas R.; Burden, Jemima J.; Nkwe, David O.; Pelchen-Matthews, Annegret; Domart, Marie-Charlotte; Durgan, Joanne; Weston, Anne; Jones, Martin L.; Peddie, Christopher J.; Carzaniga, Raffaella; Florey, Oliver; Marsh, Mark; Gutierrez, Maximiliano G.

    2017-01-01

    ABSTRACT The processes of life take place in multiple dimensions, but imaging these processes in even three dimensions is challenging. Here, we describe a workflow for 3D correlative light and electron microscopy (CLEM) of cell monolayers using fluorescence microscopy to identify and follow biological events, combined with serial blockface scanning electron microscopy to analyse the underlying ultrastructure. The workflow encompasses all steps from cell culture to sample processing, imaging strategy, and 3D image processing and analysis. We demonstrate successful application of the workflow to three studies, each aiming to better understand complex and dynamic biological processes, including bacterial and viral infections of cultured cells and formation of entotic cell-in-cell structures commonly observed in tumours. Our workflow revealed new insight into the replicative niche of Mycobacterium tuberculosis in primary human lymphatic endothelial cells, HIV-1 in human monocyte-derived macrophages, and the composition of the entotic vacuole. The broad application of this 3D CLEM technique will make it a useful addition to the correlative imaging toolbox for biomedical research. PMID:27445312

  17. Scanning transmission electron microscopy imaging and analysis

    CERN Document Server

    Pennycook, Stephen J

    2011-01-01

    Provides the first comprehensive treatment of the physics and applications of this mainstream technique for imaging and analysis at the atomic level Presents applications of STEM in condensed matter physics, materials science, catalysis, and nanoscience Suitable for graduate students learning microscopy, researchers wishing to utilize STEM, as well as for specialists in other areas of microscopy Edited and written by leading researchers and practitioners

  18. Structural examination of lithium niobate ferroelectric crystals by combining scanning electron microscopy and atomic force microscopy

    Science.gov (United States)

    Efremova, P. V.; Ped'ko, B. B.; Kuznecova, Yu. V.

    2016-02-01

    The structure of lithium niobate single crystals is studied by a complex technique that combines scanning electron microscopy and atomic force microscopy. By implementing the piezoresponse force method on an atomic force microscope, the domain structure of lithium niobate crystals, which was not revealed without electron beam irradiation, is visualized

  19. Particles and waves in electron optics and microscopy

    CERN Document Server

    Pozzi, Giulio

    2016-01-01

    Advances in Imaging and Electron Physics merges two long-running serials, Advances in Electronics and Electron Physics and Advances in Optical and Electron Microscopy. The series features extended articles on the physics of electron devices (especially semiconductor devices), particle optics at high and low energies, microlithography, image science, digital image processing, electromagnetic wave propagation, electron microscopy, and the computing methods used in all these domains. * Contains contributions from leading authorities on the subject matter* Informs and updates all the latest developments in the field of imaging and electron physics* Provides practitioners interested in microscopy, optics, image processing, mathematical morphology, electromagnetic fields, electron, and ion emission with a valuable resource* Features extended articles on the physics of electron devices (especially semiconductor devices), particle optics at high and low energies, microlithography, image science, and digital image pro...

  20. [Pulmonary hydatidosis. Comparison of cytology and scanning electron microscopy].

    Science.gov (United States)

    Lavaud, F; Nou, J M; Sadrin, R; de Montreynaud, J M; Adnet, J J

    1986-01-01

    The puncture of a hydatid cyst with a fine needle is not generally recommended as a procedure and may even be contra-indicated in the first instance. Sometimes, however, the cytologist will be surprised to discover some scolices in the aspirate when the radiology is misleading, or not suggestive, and the serology is negative. We report two cases where the diagnosis was made by the cytological examination of the aspirate. The cytological study of the liquids was compared with electron microscopy scanning, enabling the stages of development of the parasite in the tissue of the pulmonary parenchyma to be assessed.

  1. Attosecond electron pulse trains and quantum state reconstruction in ultrafast transmission electron microscopy

    Science.gov (United States)

    Priebe, Katharina E.; Rathje, Christopher; Yalunin, Sergey V.; Hohage, Thorsten; Feist, Armin; Schäfer, Sascha; Ropers, Claus

    2017-12-01

    Ultrafast electron and X-ray imaging and spectroscopy are the basis for an ongoing revolution in the understanding of dynamical atomic-scale processes in matter. The underlying technology relies heavily on laser science for the generation and characterization of ever shorter pulses. Recent findings suggest that ultrafast electron microscopy with attosecond-structured wavefunctions may be feasible. However, such future technologies call for means to both prepare and fully analyse the corresponding free-electron quantum states. Here, we introduce a framework for the preparation, coherent manipulation and characterization of free-electron quantum states, experimentally demonstrating attosecond electron pulse trains. Phase-locked optical fields coherently control the electron wavefunction along the beam direction. We establish a new variant of quantum state tomography—`SQUIRRELS'—for free-electron ensembles. The ability to tailor and quantitatively map electron quantum states will promote the nanoscale study of electron-matter entanglement and new forms of ultrafast electron microscopy down to the attosecond regime.

  2. Value of electron microscopy in the diagnosis of glomerular diseases.

    Science.gov (United States)

    Darouich, Sihem; Goucha, Rym Louzir; Jaafoura, Mohamed Habib; Moussa, Fatma Ben; Zekri, Semy; Maiz, Hédi Ben

    2010-04-01

    To evaluate the contribution of electron microscopy to the final diagnosis of glomerulopathies, the authors established a prospective study during the first semester of 2006. A total of 52 kidney biopsies were performed with 3 samples for light microscopy, immunofluorescence, and electron microscopy. Among these renal biopsies, only 20 were examined with electron microscopy because the diagnosis made on the basis of conventional methods had remained unclear or doubtful. In 18 cases, electron microscopy was undertaken for the investigation of primary kidney disease. The 2 remaining cases were transplant biopsies. In this series of 20 patients, there were 3 children with an average age of 9 years and 17 adults with an average age of 35.5 years. Fifteen patients (75%) were nephrotic. The study revealed that electron microscopy was essential for diagnosis in 8 cases (40%) and was helpful in 12 cases (60%). In conclusion, the results showed that the ultrastructural study provides essential or helpful information in many cases of glomerular diseases, and therefore electron microscopy should be considered an important tool of diagnostic renal pathology. As was recommended, it is important to reserve renal tissue for ultrastructural study unless electron microscopy can be routinely used in all biopsies. Thus, this technique could be performed wherever a renal biopsy has to be ultrastructurally evaluated.

  3. Transmission electron microscopy physics of image formation and microanalysis

    CERN Document Server

    Reimer, Ludwig

    1993-01-01

    "Transmission Electron Microscopy" presents the theory of image and contrastformation, and the analytical modes in transmission electron microscopy Theprinciples of particle and wave optics of electrons are described Electron-specimen interactions are discussed for evaluating the theory of scattering and phase contrast Also analysed are the kinetical and dynamical theories of electron diffraction and their applications for crystal-structure determination and imaging of lattices and their defects X-ray microanalysis and electron energy-loss spectroscopy are treated as analytical methods The third edition includes a brief discussionof Schottky emission guns, some clarification of minor details, and references to the recent literature

  4. Time-Resolved Scanning Electron Microscopy

    National Research Council Canada - National Science Library

    Weber, Peter M

    2006-01-01

    .... The pulsed electron beam is obtained by rapidly switching the electron emission of a field emission tip using the AC electric field arising from exposure to the intense electromagnetic radiation...

  5. Quantitative High-Resolution Transmission Electron Microscopy of Single Atoms

    OpenAIRE

    Gamm, B.; Popescu, R.; Blank, H.; Schneider, R; Beyer, A.; Gölzhäuser, A.; Gerthsen, D.

    2010-01-01

    Single atoms can be considered as basic objects for electron microscopy to test the microscope performance and basic concepts for modeling of image contrast. In this work high-resolution transmission electron microscopy was applied to image single platinum atoms in an aberration-corrected transmission electron microscope. The atoms are deposited on a self-assembled monolayer substrate which induces only negligible contrast. Single-atom contrast simulations were performed on the basis of Weick...

  6. Near-infrared branding efficiently correlates light and electron microscopy.

    Science.gov (United States)

    Bishop, Derron; Nikić, Ivana; Brinkoetter, Mary; Knecht, Sharmon; Potz, Stephanie; Kerschensteiner, Martin; Misgeld, Thomas

    2011-06-05

    The correlation of light and electron microscopy of complex tissues remains a major challenge. Here we report near-infrared branding (NIRB), which facilitates such correlation by using a pulsed, near-infrared laser to create defined fiducial marks in three dimensions in fixed tissue. As these marks are fluorescent and can be photo-oxidized to generate electron contrast, they can guide re-identification of previously imaged structures as small as dendritic spines by electron microscopy.

  7. Probing cytotoxicity of nanoparticles and organic compounds using scanning proton microscopy, scanning electron microscopy and fluorescence microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Tong Yongpeng [Institute of Nuclear Techniques, Shenzhen University, Nanhai Avenue 3688, Shenzhen 518060 (China)], E-mail: yongpengt@yahoo.com.cn; Li Changming [School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore 637457 (Singapore); Liang Feng [Institute Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai 200025 (China); Chen Jianmin [Shenzhen Municipal Hospital for Chronic Disease Control and Prevention, Guangdong 518020 (China); Zhang Hong; Liu Guoqing; Sun Huibin [Institute of Nuclear Techniques, Shenzhen University, Nanhai Avenue 3688, Shenzhen 518060 (China); Luong, John H.T. [Biotechnology Research Institute, National Research Council Canada, Montreal, Quebec, H4P 2R2 (Canada)

    2008-12-15

    Scanning proton microscopy, scanning electron microscopy (SEM) and fluorescence microscopy have been used to probe the cytotoxicity effect of benzo[a]pyrene (BaP), ethidium bromide (EB) and nanoparticles (ZnO, Al{sub 2}O{sub 3} and TiO{sub 2}) on a T lymphoblastic leukemia Jurkat cell line. The increased calcium ion (from CaCl{sub 2}) in the culture medium stimulated the accumulation of BaP and EB inside the cell, leading to cell death. ZnO, Al{sub 2}O{sub 3} and TiO{sub 2} nanoparticles, however, showed a protective effect against these two organic compounds. Such inorganic nanoparticles complexed with BaP or EB which became less toxic to the cell. Fe{sub 2}O{sub 3} nanoparticles as an insoluble particle model scavenged by macrophage were investigated in rats. They were scavenged out of the lung tissue about 48 h after infection. This result suggest that some insoluble inorganic nanoparticles of PM (particulate matters) showed protective effects on organic toxins induced acute toxic effects as they can be scavenged by macrophage cells. Whereas, some inorganic ions such as calcium ion in PM may help environmental organic toxins to penetrate cell membrane and induce higher toxic effect.

  8. Resolution Versus Error for Computational Electron Microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Luzi, Lorenzo; Stevens, Andrew; Yang, Hao; Browning, Nigel D.

    2017-07-01

    Images that are collected via scanning transmission electron microscopy (STEM) can be undersampled to avoid damage to the specimen while maintaining resolution [1, 2]. We have used BPFA to impute missing data and reduce noise [3]. The reconstruction is typically evaluated using the peak signal-to-noise ratio (PSNR). This measure is too conservative for STEM images and we propose that the Fourier ring correlation (FRC) is used instead to evaluate the reconstruction. We are not concerned with exact reconstruction of the truth image, and therefore PSNR is a conservative estimation of the quality of the reconstruction. Instead, we are concerned with the visual resolution of the image and whether atoms can be distinguished. We have evaluated the reconstruction of a simulated STEM image using the FRC and compared the results with the PSNR measurements. The FRC captures the resolution of the image and is not affected by a large MSE if the atom peaks are still distinguishable. The noisy and reconstructed images are shown in Figure 1. The simulated STEM image was sampled at 100%, 80%, 40%, and 20% of the original pixels to simulate an undersampled scan. The reconstruction was done using BPFA with a patch size of 10 x 10 and no overlapping patches. Not having overlapping patches produces inferior results but they are still acceptable. The dictionary size is 64 and 30 iterations were completed during each reconstruction. The 100% image was denoised instead of reconstructed. Poisson noise was applied to the simulated image with λ values of 500, 50, and 5 to simulate lower imaging dose. The original simulated STEM image was also included in our calculations and was generated using a dose of 1000. The simulated STEM image is 100 by 100 pixels and has essentially no high frequency components. The image reconstruction tends to smooth the data, also resulting in no high frequency components. This causes the FRC of the two images to be large at higher resolutions and may be

  9. Ion-induced electron emission microscopy

    Science.gov (United States)

    Doyle, Barney L.; Vizkelethy, Gyorgy; Weller, Robert A.

    2001-01-01

    An ion beam analysis system that creates multidimensional maps of the effects of high energy ions from an unfocussed source upon a sample by correlating the exact entry point of an ion into a sample by projection imaging of the secondary electrons emitted at that point with a signal from a detector that measures the interaction of that ion within the sample. The emitted secondary electrons are collected in a strong electric field perpendicular to the sample surface and (optionally) projected and refocused by the electron lenses found in a photon emission electron microscope, amplified by microchannel plates and then their exact position is sensed by a very sensitive X Y position detector. Position signals from this secondary electron detector are then correlated in time with nuclear, atomic or electrical effects, including the malfunction of digital circuits, detected within the sample that were caused by the individual ion that created these secondary electrons in the fit place.

  10. Low dose techniques and cryo-electron microscopy.

    Science.gov (United States)

    Fujiyoshi, Yoshinori

    2013-01-01

    Our understanding of subcellular structures has been greatly increased owing to electron microscopy, even though radiation damage of biological samples by the electron beam demanded staining techniques. Technological and instrumental advances of electron microscopy have, however, established various highly sophisticated techniques to study biological systems in their native states without staining and thus facilitated comprehension of rather intact structures of biological components. Among these techniques, electron crystallography is a well-established one to analyze membrane protein structures within lipid bilayers, without staining at close-to-physiological conditions. Structures of membrane proteins could be analyzed at resolutions better than 3Å by electron crystallography due to techniques of low dose and cryo-electron microscopy (cryo-EM). Here, recent cryo-EM technological and instrumental advances crucial to optimal data collection in electron crystallography are summarized as well as examples of structures of membrane proteins analyzed with the help of this method.

  11. Image Resolution in Scanning Transmission Electron Microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Pennycook, S. J.; Lupini, A.R.

    2008-06-26

    Digital images captured with electron microscopes are corrupted by two fundamental effects: shot noise resulting from electron counting statistics and blur resulting from the nonzero width of the focused electron beam. The generic problem of computationally undoing these effects is called image reconstruction and for decades has proved to be one of the most challenging and important problems in imaging science. This proposal concerned the application of the Pixon method, the highest-performance image-reconstruction algorithm yet devised, to the enhancement of images obtained from the highest-resolution electron microscopes in the world, now in operation at Oak Ridge National Laboratory.

  12. Transmission electron microscopy physics of image formation and microanalysis

    CERN Document Server

    Reimer, Ludwig

    1989-01-01

    The aim of this book is to present the theory of image and contrast formation and the analytical modes in transmission electron microscopy The principles of particle and wave optics of electrons are described Electron-specimen interactions are discussed for evaluating the theory of scattering and phase contrast Also discussed are the kinematical and dynamical theories of electron diffraction and their applications for crystal structure determination and imaging of lattice defects X-ray microanalysis and energy-loss spectroscopy are treated as analytical methods The second edition includes discussion of recent progress, especially in the areas of energy-loss spectroscopy, crystal-lattice imaging and reflection electron microscopy

  13. Preparation of single-celled marine dinoflagellates for electron microscopy.

    Science.gov (United States)

    Truby, E W

    1997-02-15

    Electron microscopy has been used successfully to study and identify single-celled marine dinoflagellates including parasitic ones and others, such as those that cause red tide. Delicate cells can be preserved for scanning electron microscopy with a combined glutaraldehydeosmium tetroxide mixture that is adjusted for the osmolality of the medium. The protocol allows resolution of fine morphological features. Preservation for transmission electron microscopy can be accomplished with a standard glutaraldehyde fixation and osmium-tetroxide post-fixation in a suitable buffer, but again, the osmolality of the mixture must be adjusted. The protocol allows ultrastructural resolution of vesiculated cells and has been modified for small sample sizes.

  14. Very low energy electron microscopy of graphene flakes.

    Science.gov (United States)

    Mikmeková, E; Bouyanfif, H; Lejeune, M; Müllerová, I; Hovorka, M; Unčovský, M; Frank, L

    2013-08-01

    Commercially available graphene samples are examined by Raman spectroscopy and very low energy scanning transmission electron microscopy. Limited lateral resolution of Raman spectroscopy may produce a Raman spectrum corresponding to a single graphene layer even for flakes that can be identified by very low energy electron microscopy as an aggregate of smaller flakes of various thicknesses. In addition to diagnostics of graphene samples at larger dimensions, their electron transmittance can also be measured at very low energies. © 2013 The Authors Journal of Microscopy © 2013 Royal Microscopical Society.

  15. The origins and evolution of freeze-etch electron microscopy

    Science.gov (United States)

    Heuser, John E.

    2011-01-01

    The introduction of the Balzers freeze-fracture machine by Moor in 1961 had a much greater impact on the advancement of electron microscopy than he could have imagined. Devised originally to circumvent the dangers of classical thin-section techniques, as well as to provide unique en face views of cell membranes, freeze-fracturing proved to be crucial for developing modern concepts of how biological membranes are organized and proved that membranes are bilayers of lipids within which proteins float and self-assemble. Later, when freeze-fracturing was combined with methods for freezing cells that avoided the fixation and cryoprotection steps that Moor still had to use to prepare the samples for his original invention, it became a means for capturing membrane dynamics on the millisecond time-scale, thus allowing a deeper understanding of the functions of biological membranes in living cells as well as their static ultrastructure. Finally, the realization that unfixed, non-cryoprotected samples could be deeply vacuum-etched or even freeze-dried after freeze-fracturing opened up a whole new way to image all the other molecular components of cells besides their membranes and also provided a powerful means to image the interactions of all the cytoplasmic components with the various membranes of the cell. The purpose of this review is to outline the history of these technical developments, to describe how they are being used in electron microscopy today and to suggest how they can be improved in order to further their utility for biological electron microscopy in the future. PMID:21844598

  16. Computer-Aided Design for Electron Microscopy

    Czech Academy of Sciences Publication Activity Database

    Lencová, Bohumila

    2004-01-01

    Roč. 6, č. 1 (2004), s. 51-53 ISSN 1439-4243 Institutional research plan: CEZ:AV0Z2065902 Keywords : magnetic electron lenses * accuracy of computation * computer-aided design Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

  17. Transmission electron microscopy physics of image formation and microanalysis

    CERN Document Server

    Reimer, Ludwig

    1997-01-01

    Transmission Electron Microscopy presents the theory of image and contrast formation, and the analytical modes in transmission electron microscopy. The principles of particle and wave optics of electrons are described. Electron-specimen interactions are discussed for evaluating the theory of scattering and phase contrast. Also discussed are the kinematical and dynamical theories of electron diffraction and their applications for crystal-structure analysis and imaging of lattices and their defects. X-ray micronanalysis and electron energy-loss spectroscopy are treated as analytical methods. Specimen damage and contamination by electron irradiation limits the resolution for biological and some inorganic specimens. This fourth edition includes discussion of recent progress, especially in the area of Schottky emission guns, convergent-beam electron diffraction, electron tomography, holography and the high resolution of crystal lattices.

  18. Chapter 14: Electron Microscopy on Thin Films for Solar Cells

    Energy Technology Data Exchange (ETDEWEB)

    Romero, Manuel [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Abou-Ras, Daniel [Helmholtz-Zentrum Berlin fur Materialien und Energie GmbH (HZB); Nichterwitz, Melanie [Helmholtz-Zentrum Berlin fur Materialien und Energie GmbH (HZB); Schmidt, Sebastian S. [Helmholtz-Zentrum Berlin fur Materialien und Energie GmbH (HZB)

    2016-07-22

    This chapter overviews the various techniques applied in scanning electron microscopy (SEM) and transmission electron microscopy (TEM), and highlights their possibilities and also limitations. It gives the various imaging and analysis techniques applied on a scanning electron microscope. The chapter shows that imaging is divided into that making use of secondary electrons (SEs) and of backscattered electrons (BSEs), resulting in different contrasts in the images and thus providing information on compositions, microstructures, and surface potentials. Whenever aiming for imaging and analyses at scales of down to the angstroms range, TEM and its related techniques are appropriate tools. In many cases, also SEM techniques provide the access to various material properties of the individual layers, not requiring specimen preparation as time consuming as TEM techniques. Finally, the chapter dedicates to cross-sectional specimen preparation for electron microscopy. The preparation decides indeed on the quality of imaging and analyses.

  19. Correlative fluorescence and electron microscopy in tissues: immunocytochemistry.

    Science.gov (United States)

    Robinson, J M; Takizawa, T

    2009-09-01

    Correlative microscopy is a collection of procedures that rely upon two or more imaging modalities to examine the same specimen. The imaging modalities employed should each provide unique information and the combined correlative data should be more information rich than that obtained by any of the imaging methods alone. Currently the most common form of correlative microscopy combines fluorescence and electron microscopy. While much of the correlative microscopy in the literature is derived from studies of model cell culture systems we have focused, primarily, on correlative microscopy in tissue samples. The use of tissue, particularly human tissue, may add constraints not encountered in cell culture systems. Ultrathin cryosections, typically used for immunoelectron microscopy, have served as the substrate for correlative fluorescence and electron microscopic immunolocalization in our studies. In this work, we have employed the bifunctional reporter FluoroNanogold. This labeling reagent contains both a fluorochrome and a gold-cluster compound and can be imaged by sequential fluorescence and electron microscopy. This approach permits the examination of exactly the same sub-cellular structures in both fluorescence and electron microscopy with a high level of spatial resolution.

  20. Cryo-Electron Microscopy (ANDS Tech Talk).pdf

    OpenAIRE

    Wilson, Lance

    2016-01-01

    An introduction to the cryo-electron microscopy processing. Included is an example of a ten fold increase in processing speed using the MASSIVE faciltiy. Please contact me for further information and scripts to parallelise this work.

  1. Very low energy electron microscopy of graphene flakes

    National Research Council Canada - National Science Library

    MIKMEKOVÁ, E; BOUYANFIF, H; LEJEUNE, M; MÜLLEROVÁ, I; HOVORKA, M; UNČOVSKÝ, M; FRANK, L

    2013-01-01

    .... Limited lateral resolution of Raman spectroscopy may produce a Raman spectrum corresponding to a single graphene layer even for flakes that can be identified by very low energy electron microscopy...

  2. Applications of orientation mapping by scanning and transmission electron microscopy

    DEFF Research Database (Denmark)

    Juul Jensen, D.

    1997-01-01

    The potentials of orientation mapping techniques (in the following referred to as OIM) for studies of thermomechanical processes are analysed. Both transmission electron microscopy (TEM) and scanning electron microscopy (SEM) based OIM techniques are considered. Among the thermomechanical processes...... information is achieved when the results of OIM and these various techniques are combined. Examples hereof are given to illustrate the potentials of OIM techniques. Finally, limitations of TEM and SEM based OIM for specific applications are discussed....

  3. Usefulness of electron microscopy in the diagnosis of cardiac sarcoidosis.

    Science.gov (United States)

    Takemura, G; Takatsu, Y; Ono, K; Miyatake, T; Ono, M; Izumi, T; Fujiwara, H

    1995-01-01

    A 49-year-old man with cardiac sarcoidosis is presented. He suffered from congestive heart failure, and left ventricular asynergy and reduced function was evident by echocardiogram and left ventriculogram. A light microscopic examination of the endomyocardial biopsy revealed nonspecific myocarditis without giant cells or noncaseating granulomas. Under an electron microscope, however, several epithelioid cells were found in the specimen. The serum level of lysozyme was elevated. The patient had a past history of sarcoidosis of the eyes and lungs 22 years previously. Cardiac diseases presenting epithelioid cells other than sarcoidosis were clinically ruled out. Thus, the diagnosis of cardiac sarcoidosis was made based on both clinical and ultrastructural findings, and corticosteroid therapy was initiated. In the second biopsy, performed 4 months later, a noncaseating granuloma was found. Generally, the incidence of histological diagnosis of cardiac sarcoidosis by light microscopy is relatively low in endomyocardial biopsy specimens. The present case suggests that the addition of an ultrastructural examination may improve the diagnostic usefulness of the endomyocardial biopsy in cardiac sarcoidosis, since electron microscopy can clearly identify the presence of even one epithelioid cell.

  4. Photoconversion of CFP to study neuronal tissue with electron microscopy.

    Science.gov (United States)

    Wittenmayer, Nina

    2014-01-01

    Being able to use versatile light microscopy on live or fixed samples followed by electron microscopy imaging for high resolution analyses is a challenging goal. The advantage is of course that tracing and localizing fluorescently labeled molecules yields great information about dynamic cellular processes, while electron microscopy of the same sample provides exquisite information about subcellular structures. Here, I describe the straightforward combination of both methods by photoconversion of diaminobenzidine (DAB) through cyan fluorescent protein (CFP) tagged proteins localized to the Golgi apparatus in primary hippocampal neurons.

  5. Exploring the third dimension: volume electron microscopy comes of age.

    Science.gov (United States)

    Peddie, Christopher J; Collinson, Lucy M

    2014-06-01

    Groundbreaking advances in volume electron microscopy and specimen preparation are enabling the 3-dimensional visualisation of specimens with unprecedented detail, and driving a gratifying resurgence of interest in the ultrastructural examination of cellular systems. Serial section techniques, previously the domain of specialists, are becoming increasingly automated with the development of systems such as the automatic tape-collecting ultramicrotome, and serial blockface and focused ion beam scanning electron microscopes. These changes are rapidly broadening the scope of biomedical studies to which volume electron microscopy techniques can be applied beyond the brain. Further innovations in microscope design are also in the pipeline, which have the potential to enhance the speed and quality of data collection. The recent introduction of integrated light and electron microscopy systems will revolutionise correlative light and volume electron microscopy studies, by enabling the sequential collection of data from light and electron imaging modalities without intermediate specimen manipulation. In doing so, the acquisition of comprehensive functional information and direct correlation with ultrastructural details within a 3-dimensional reference space will become routine. The prospects for volume electron microscopy are therefore bright, and the stage is set for a challenging and exciting future. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

  6. Cryo scanning electron microscopy of Plasmodium falciparum-infected erythrocytes.

    Science.gov (United States)

    Hempel, Casper

    2017-07-01

    Plasmodium falciparum invades erythrocytes as an essential part of their life cycle. While living inside erythrocytes, the parasite remodels the cell's intracellular organization as well as its outer surface. Late trophozoite-stage parasites and schizonts introduce numerous small protrusions on the erythrocyte surface, called knobs. Current methods for studying these knobs include atomic force microscopy and electron microscopy. Standard electron microscopy methods rely on chemical fixation and dehydration modifying cell size. Here, a novel method is presented using rapid freezing and scanning electron microscopy under cryogenic conditions allowing for high resolution and magnification of erythrocytes. This novel technique can be used for precise estimates of knob density and for studies on cytoadhesion. © 2017 APMIS. Published by John Wiley & Sons Ltd.

  7. Single-shot dynamic transmission electron microscopy

    Science.gov (United States)

    LaGrange, T.; Armstrong, M. R.; Boyden, K.; Brown, C. G.; Campbell, G. H.; Colvin, J. D.; DeHope, W. J.; Frank, A. M.; Gibson, D. J.; Hartemann, F. V.; Kim, J. S.; King, W. E.; Pyke, B. J.; Reed, B. W.; Shirk, M. D.; Shuttlesworth, R. M.; Stuart, B. C.; Torralva, B. R.; Browning, N. D.

    2006-07-01

    A dynamic transmission electron microscope (DTEM) has been designed and implemented to study structural dynamics in condensed matter systems. The DTEM is a conventional in situ transmission electron microscope (TEM) modified to drive material processes with a nanosecond laser, "pump" pulse and measure it shortly afterward with a 30-ns-long probe pulse of ˜107 electrons. An image with a resolution of <20nm may be obtained with a single pulse, largely eliminating the need to average multiple measurements and enabling the study of unique, irreversible events with nanosecond- and nanometer-scale resolution. Space charge effects, while unavoidable at such a high current, may be kept to reasonable levels by appropriate choices of operating parameters. Applications include the study of phase transformations and defect dynamics at length and time scales difficult to access with any other technique. This single-shot approach is complementary to stroboscopic TEM, which is capable of much higher temporal resolution but is restricted to the study of processes with a very high degree of repeatability.

  8. Telocytes and putative stem cells in the lungs: electron microscopy, electron tomography and laser scanning microscopy.

    Science.gov (United States)

    Popescu, Laurentiu M; Gherghiceanu, Mihaela; Suciu, Laura C; Manole, Catalin G; Hinescu, Mihail E

    2011-09-01

    This study describes a novel type of interstitial (stromal) cell - telocytes (TCs) - in the human and mouse respiratory tree (terminal and respiratory bronchioles, as well as alveolar ducts). TCs have recently been described in pleura, epicardium, myocardium, endocardium, intestine, uterus, pancreas, mammary gland, etc. (see www.telocytes.com ). TCs are cells with specific prolongations called telopodes (Tp), frequently two to three per cell. Tp are very long prolongations (tens up to hundreds of μm) built of alternating thin segments known as podomers (≤ 200 nm, below the resolving power of light microscope) and dilated segments called podoms, which accommodate mitochondria, rough endoplasmic reticulum and caveolae. Tp ramify dichotomously, making a 3-dimensional network with complex homo- and heterocellular junctions. Confocal microscopy reveals that TCs are c-kit- and CD34-positive. Tp release shed vesicles or exosomes, sending macromolecular signals to neighboring cells and eventually modifying their transcriptional activity. At bronchoalveolar junctions, TCs have been observed in close association with putative stem cells (SCs) in the subepithelial stroma. SCs are recognized by their ultrastructure and Sca-1 positivity. Tp surround SCs, forming complex TC-SC niches (TC-SCNs). Electron tomography allows the identification of bridging nanostructures, which connect Tp with SCs. In conclusion, this study shows the presence of TCs in lungs and identifies a TC-SC tandem in subepithelial niches of the bronchiolar tree. In TC-SCNs, the synergy of TCs and SCs may be based on nanocontacts and shed vesicles.

  9. Characterization of Polycaprolactone Films Biodeterioration by Scanning Electron Microscopy

    Czech Academy of Sciences Publication Activity Database

    Hrubanová, Kamila; Voberková, S.; Hermanová, S.; Krzyžánek, Vladislav

    2014-01-01

    Roč. 20, S3 (2014), s. 1950-1951 ISSN 1431-9276 R&D Projects: GA MŠk EE.2.3.20.0103; GA MŠk(CZ) LO1212 Institutional support: RVO:68081731 Keywords : polycaprolactone films * biodeterioration * scanning electron microscopy Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 1.877, year: 2014

  10. Electron Microscopy of Staphylococcus aureus Cell Wall Lysis

    Science.gov (United States)

    Virgilio, R.; González, C.; Muñoz, Nubia; Mendoza, Silvia

    1966-01-01

    Virgilio, Rafael (Escuela de Química y Farmacia, Universidad de Chile, Santiago, Chile), C. González, Nubia Muñoz, and Silvia Mendoza. Electron microscopy of Staphylococcus aureus cell wall lysis. J. Bacteriol. 91:2018–2024. 1966.—A crude suspension of Staphylococcus aureus cell walls (strain Cowan III) in buffer solution was shown by electron microscopy to lyse slightly after 16 hr, probably owing to the action of autolysin. The lysis was considerably faster and more intense after the addition of lysozyme. A remarkable reduction in thickness and rigidity of the cell walls, together with the appearance of many irregular protrusions in their outlines, was observed after 2 hr; after 16 hr, there remained only a few recognizable cell wall fragments but many residual particulate remnants. When autolysin was previously inactivated by trypsin, there was a complete inhibition of the lytic action of lysozyme; on the other hand, when autolysin was inactivated by heat and lysozyme was added, a distinct decrease in the thickness of the cell walls was observed, but there was no destruction of the walls. The lytic action of lysozyme, after treatment with hot 5% trichloroacetic acid, gave rise to a marked dissolution of the structure of the cell walls, which became lost against the background, without, however, showing ostensible alteration of wall outlines. From a morphological point of view, the lytic action of autolysin plus lysozyme was quite different from that of trichloroacetic acid plus lysozyme, as shown by electron micrographs, but in both cases it was very intense. This would suggest different mechanisms of action for these agents. Images PMID:5939482

  11. Transmission electron microscopy of mercury metal

    KAUST Repository

    Anjum, Dalaver H.

    2016-03-28

    Summary: Transmission electron microcopy (TEM) analysis of liquid metals, especially mercury (Hg), is difficult to carry out because their specimen preparation poses a daunting task due to the unique surface properties of these metals. This paper reports a cryoTEM study on Hg using a novel specimen preparation technique. Hg metal is mixed with water using sonication and quenched in liquid ethane cryogen. This technique permits research into the morphological, phase and structural properties of Hg at nanoscale dimensions. © 2016 Royal Microscopical Society.

  12. Cryo-Scanning Electron Microscopy of Captured Cirrus Ice Particles

    Science.gov (United States)

    Magee, N. B.; Boaggio, K.; Bandamede, M.; Bancroft, L.; Hurler, K.

    2016-12-01

    We present the latest collection of high-resolution cryo-scanning electron microscopy images and microanalysis of cirrus ice particles captured by high-altitude balloon (ICE-Ball, see abstracts by K. Boaggio and M. Bandamede). Ice particle images and sublimation-residues are derived from particles captured during approximately 15 balloon flights conducted in Pennsylvania and New Jersey over the past 12 months. Measurements include 3D digital elevation model reconstructions of ice particles, and associated statistical analyses of entire particles and particle sub-facets and surfaces. This 3D analysis reveals that morphologies of most ice particles captured deviate significantly from ideal habits, and display geometric complexity and surface roughness at multiple measureable scales, ranging from 100's nanometers to 100's of microns. The presentation suggests potential a path forward for representing scattering from a realistically complex array of ice particle shapes and surfaces.

  13. Electron microscopy methods in studies of cultural heritage sites

    Energy Technology Data Exchange (ETDEWEB)

    Vasiliev, A. L., E-mail: a.vasiliev56@gmail.com; Kovalchuk, M. V.; Yatsishina, E. B. [National Research Centre “Kurchatov Institute” (Russian Federation)

    2016-11-15

    The history of the development and application of scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy-dispersive X-ray microanalysis (EDXMA) in studies of cultural heritage sites is considered. In fact, investigations based on these methods began when electron microscopes became a commercial product. Currently, these methods, being developed and improved, help solve many historical enigmas. To date, electron microscopy combined with microanalysis makes it possible to investigate any object, from parchment and wooden articles to pigments, tools, and objects of art. Studies by these methods have revealed that some articles were made by ancient masters using ancient “nanotechnologies”; hence, their comprehensive analysis calls for the latest achievements in the corresponding instrumental methods and sample preparation techniques.

  14. Contributed review: Review of integrated correlative light and electron microscopy.

    Science.gov (United States)

    Timmermans, F J; Otto, C

    2015-01-01

    New developments in the field of microscopy enable to acquire increasing amounts of information from large sample areas and at an increased resolution. Depending on the nature of the technique, the information may reveal morphological, structural, chemical, and still other sample characteristics. In research fields, such as cell biology and materials science, there is an increasing demand to correlate these individual levels of information and in this way to obtain a better understanding of sample preparation and specific sample properties. To address this need, integrated systems were developed that combine nanometer resolution electron microscopes with optical microscopes, which produce chemically or label specific information through spectroscopy. The complementary information from electron microscopy and light microscopy presents an opportunity to investigate a broad range of sample properties in a correlated fashion. An important part of correlating the differences in information lies in bridging the different resolution and image contrast features. The trend to analyse samples using multiple correlated microscopes has resulted in a new research field. Current research is focused, for instance, on (a) the investigation of samples with nanometer scale distribution of inorganic and organic materials, (b) live cell analysis combined with electron microscopy, and (c) in situ spectroscopic and electron microscopy analysis of catalytic materials, but more areas will benefit from integrated correlative microscopy.

  15. Correlative light- and electron microscopy with chemical tags.

    Science.gov (United States)

    Perkovic, Mario; Kunz, Michael; Endesfelder, Ulrike; Bunse, Stefanie; Wigge, Christoph; Yu, Zhou; Hodirnau, Victor-Valentin; Scheffer, Margot P; Seybert, Anja; Malkusch, Sebastian; Schuman, Erin M; Heilemann, Mike; Frangakis, Achilleas S

    2014-05-01

    Correlative microscopy incorporates the specificity of fluorescent protein labeling into high-resolution electron micrographs. Several approaches exist for correlative microscopy, most of which have used the green fluorescent protein (GFP) as the label for light microscopy. Here we use chemical tagging and synthetic fluorophores instead, in order to achieve protein-specific labeling, and to perform multicolor imaging. We show that synthetic fluorophores preserve their post-embedding fluorescence in the presence of uranyl acetate. Post-embedding fluorescence is of such quality that the specimen can be prepared with identical protocols for scanning electron microscopy (SEM) and transmission electron microscopy (TEM); this is particularly valuable when singular or otherwise difficult samples are examined. We show that synthetic fluorophores give bright, well-resolved signals in super-resolution light microscopy, enabling us to superimpose light microscopic images with a precision of up to 25 nm in the x-y plane on electron micrographs. To exemplify the preservation quality of our new method we visualize the molecular arrangement of cadherins in adherens junctions of mouse epithelial cells. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

  16. A correlative optical microscopy and scanning electron microscopy approach to locating nanoparticles in brain tumors.

    Science.gov (United States)

    Kempen, Paul J; Kircher, Moritz F; de la Zerda, Adam; Zavaleta, Cristina L; Jokerst, Jesse V; Mellinghoff, Ingo K; Gambhir, Sanjiv S; Sinclair, Robert

    2015-01-01

    The growing use of nanoparticles in biomedical applications, including cancer diagnosis and treatment, demands the capability to exactly locate them within complex biological systems. In this work a correlative optical and scanning electron microscopy technique was developed to locate and observe multi-modal gold core nanoparticle accumulation in brain tumor models. Entire brain sections from mice containing orthotopic brain tumors injected intravenously with nanoparticles were imaged using both optical microscopy to identify the brain tumor, and scanning electron microscopy to identify the individual nanoparticles. Gold-based nanoparticles were readily identified in the scanning electron microscope using backscattered electron imaging as bright spots against a darker background. This information was then correlated to determine the exact location of the nanoparticles within the brain tissue. The nanoparticles were located only in areas that contained tumor cells, and not in the surrounding healthy brain tissue. This correlative technique provides a powerful method to relate the macro- and micro-scale features visible in light microscopy with the nanoscale features resolvable in scanning electron microscopy. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. Towards Automated Nanomanipulation under Scanning Electron Microscopy

    Science.gov (United States)

    Ye, Xutao

    Robotic Nanomaterial Manipulation inside scanning electron microscopes (SEM) is useful for prototyping functional devices and characterizing one-dimensional nanomaterial's properties. Conventionally, manipulation of nanowires has been performed via teleoperation, which is time-consuming and highly skill-dependent. Manual manipulation also has the limitation of low success rates and poor reproducibility. This research focuses on a robotic system capable of automated pick-place of single nanowires. Through SEM visual detection and vision-based motion control, the system transferred individual silicon nanowires from their growth substrate to a microelectromechanical systems (MEMS) device that characterized the nanowires' electromechanical properties. The performances of the nanorobotic pick-up and placement procedures were quantified by experiments. The system demonstrated automated nanowire pick-up and placement with high reliability. A software system for a load-lock-compatible nanomanipulation system is also designed and developed in this research.

  18. Applicability of thin film phase plates in biological electron microscopy

    OpenAIRE

    Danev, Radostin; Nagayama, Kuniaki

    2006-01-01

    Presented is an evaluation of phase contrast techniques in transmission electron microscopy. The traditional defocus phase contrast is compared to two recently developed phase plate techniques. One is the Zernike phase contrast transmission electron microscope, the other is the Hilbert differential contrast thransmission electron microscope. The imaging characteristics of each technique are discussed. Phase plate techniques provide improved contrast for ice-embedded biological samples which a...

  19. Electron Microscopy of Nephropathia Epidemica. Glomerular changes.

    Science.gov (United States)

    Collan, Y; Lähdevirta, J; Jokinen, E J

    1978-02-10

    Electron microscopical changes in the glomeruli in 20 kidney biopsies from 18 patients, who were suffering from or had lately suffered from Nephropathia epidemica were studied. Various kinds of deposits were seen. Under the endothelial cells there were collections of light flocculent material. Small dark deposits were seen in the mesangium at the mesangial cell processes, inside the thickened basement membrane, and occasionally on the epithelial side of the membrane. Large deposits were seen around mesangial cells in the mesangium. Deposits were less numerous than in chronic immune complex diseases. The intramembranous or subepithelial deposits were associated with "moon craters", membranous convoluted structures or membrane debris. Granular extracellular mesangial material, round extracellular particles and intraendothelial microtubular inclusions were occasionally seen. In two of our cases occasional capsular epithelial cells showed numerous myelin bodies. Typical viruses were not seen in the glomeruli. The findings are in accord with the short period of scanty immune complex deposition in the glomeruli in the clinically active phase of Nephropathia epidemica.

  20. Transmission Electron Microscopy of Itokawa Regolith Grains

    Science.gov (United States)

    Keller, Lindsay P.; Berger, E. L.

    2013-01-01

    Introduction: In a remarkable engineering achievement, the JAXA space agency successfully recovered the Hayabusa space-craft in June 2010, following a non-optimal encounter and sur-face sampling mission to asteroid 25143 Itokawa. These are the first direct samples ever obtained and returned from the surface of an asteroid. The Hayabusa samples thus present a special op-portunity to directly investigate the evolution of asteroidal sur-faces, from the development of the regolith to the study of the effects of space weathering. Here we report on our preliminary TEM measurements on two Itokawa samples. Methods: We were allocated particles RA-QD02-0125 and RA-QD02-0211. Both particles were embedded in low viscosity epoxy and thin sections were prepared using ultramicrotomy. High resolution images and electron diffraction data were ob-tained using a JEOL 2500SE 200 kV field-emission scanning-transmission electron microscope. Quantitative maps and anal-yses were obtained using a Thermo thin-window energy-dispersive x-ray (EDX) spectrometer. Results: Both particles are olivine-rich (Fo70) with µm-sized inclusions of FeS and have microstructurally complex rims. Par-ticle RA-QD02-0125 is rounded and has numerous sub-µm grains attached to its surface including FeS, albite, olivine, and rare melt droplets. Solar flare tracks have not been observed, but the particle is surrounded by a continuous 50 nm thick, stuctur-ally disordered rim that is compositionally similar to the core of the grain. One of the surface adhering grains is pyrrhotite show-ing a S-depleted rim (8-10 nm thick) with nanophase Fe metal grains (<5 nm) decorating the outermost surface. The pyrrhotite displays a complex superstructure in its core that is absent in the S-depleted rim. Particle RA-QD02-0211 contains solar flare particle tracks (2x109 cm-2) and shows a structurally disordered rim 100 nm thick. The track density corresponds to a surface exposure of 103-104 years based on the track production rate

  1. Big Data Analytics for Scanning Transmission Electron Microscopy Ptychography

    OpenAIRE

    Jesse, S.; Chi, M.; Belianinov, A.; Beekman, C.; Kalinin, S. V.; Borisevich, A. Y.; Lupini, A. R.

    2016-01-01

    Electron microscopy is undergoing a transition; from the model of producing only a few micrographs, through the current state where many images and spectra can be digitally recorded, to a new mode where very large volumes of data (movies, ptychographic and multi-dimensional series) can be rapidly obtained. Here, we discuss the application of so-called ?big-data? methods to high dimensional microscopy data, using unsupervised multivariate statistical techniques, in order to explore salient ima...

  2. Biological applications of phase-contrast electron microscopy.

    Science.gov (United States)

    Nagayama, Kuniaki

    2014-01-01

    Here, I review the principles and applications of phase-contrast electron microscopy using phase plates. First, I develop the principle of phase contrast based on a minimal model of microscopy, introducing a double Fourier-transform process to mathematically formulate the image formation. Next, I explain four phase-contrast (PC) schemes, defocus PC, Zernike PC, Hilbert differential contrast, and schlieren optics, as image-filtering processes in the context of the minimal model, with particular emphases on the Zernike PC and corresponding Zernike phase plates. Finally, I review applications of Zernike PC cryo-electron microscopy to biological systems such as protein molecules, virus particles, and cells, including single-particle analysis to delineate three-dimensional (3D) structures of protein and virus particles and cryo-electron tomography to reconstruct 3D images of complex protein systems and cells.

  3. Imaging hydrated microbial extracellular polymers: Comparative analysis by electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Dohnalkova, A.C.; Marshall, M. J.; Arey, B. W.; Williams, K. H.; Buck, E. C.; Fredrickson, J. K.

    2011-01-01

    Microbe-mineral and -metal interactions represent a major intersection between the biosphere and geosphere but require high-resolution imaging and analytical tools for investigating microscale associations. Electron microscopy has been used extensively for geomicrobial investigations and although used bona fide, the traditional methods of sample preparation do not preserve the native morphology of microbiological components, especially extracellular polymers. Herein, we present a direct comparative analysis of microbial interactions using conventional electron microscopy approaches of imaging at room temperature and a suite of cryogenic electron microscopy methods providing imaging in the close-to-natural hydrated state. In situ, we observed an irreversible transformation of the hydrated bacterial extracellular polymers during the traditional dehydration-based sample preparation that resulted in their collapse into filamentous structures. Dehydration-induced polymer collapse can lead to inaccurate spatial relationships and hence could subsequently affect conclusions regarding nature of interactions between microbial extracellular polymers and their environment.

  4. Correlative microscopy: bridging the gap between fluorescence light microscopy and cryo-electron tomography.

    Science.gov (United States)

    Sartori, Anna; Gatz, Rudolf; Beck, Florian; Rigort, Alexander; Baumeister, Wolfgang; Plitzko, Juergen M

    2007-11-01

    Cryo-electron tomography of frozen-hydrated biological samples offers a means of studying large and complex cellular structures in three-dimensions and with nanometer-scale resolution. The low contrast of unstained biological material embedded in amorphous ice and the need to minimise the exposure of these radiation-sensitive samples to the electron beam result in a poor signal-to-noise ratio. This poses problems not only in the visualisation and interpretation of such tomograms, it is also a problem in surveying the sample and in finding regions which contain the features of interest and which are suitable for recording tomograms. To address this problem, we have developed a correlative fluorescence light microscopy-electron microscopy approach, which guides the search for the structures of interest and allows electron microscopy to zoom in on them. With our approach, the total dose spent on locating regions of interest is negligible. A newly designed cryo-holder allows imaging of fluorescently labelled samples after vitrification. The absolute coordinates of structures identified and located by cryo-light microscopy are transferred to the electron microscope via a Matlab-based user interface. We have successfully tested the experimental setup and the whole procedure with two types of adherent fluorescently labelled cells, a neuronal cell line and keratinocytes, both grown directly on EM grids.

  5. Surface morphology of Trichinella spiralis by scanning electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Kim, C.W. (State Univ. of New York, Stony Brook); Ledbetter, M.C.

    1980-02-01

    The surface morphology of larval and adult Trichinella spiralis was studied by scanning electron microscopy (SEM) of fixed, dried, and metal-coated specimens. The results are compared with those found earlier by various investigators using light and transmission electron microscopy. Some morphological features reported here are revealed uniquely by SEM. These include the pores of the cephalic sense organs, the character of secondary cuticular folds, variations of the hypodermal gland cell openings or pores, and the presence of particles on the copulatory bell.

  6. Optimising electron microscopy experiment through electron optics simulation

    Energy Technology Data Exchange (ETDEWEB)

    Kubo, Y. [CEMES-CNRS, 29 Rue Jeanne Marvig, 31055 Toulouse France (France); Hitachi High-Technologies Corporation, 882, Ichige, Hitachinaka, Ibaraki 312-8504 (Japan); Gatel, C.; Snoeck, E. [CEMES-CNRS, 29 Rue Jeanne Marvig, 31055 Toulouse France (France); Houdellier, F., E-mail: florent.houdellier@cemes.fr [CEMES-CNRS, 29 Rue Jeanne Marvig, 31055 Toulouse France (France)

    2017-04-15

    We developed a new type of electron trajectories simulation inside a complete model of a modern transmission electron microscope (TEM). Our model incorporates the precise and real design of each element constituting a TEM, i.e. the field emission (FE) cathode, the extraction optic and acceleration stages of a 300 kV cold field emission gun, the illumination lenses, the objective lens, the intermediate and projection lenses. Full trajectories can be computed using magnetically saturated or non-saturated round lenses, magnetic deflectors and even non-cylindrical symmetry elements like electrostatic biprism. This multi-scale model gathers nanometer size components (FE tip) with parts of meter length (illumination and projection systems). We demonstrate that non-trivial TEM experiments requiring specific and complex optical configurations can be simulated and optimized prior to any experiment using such model. We show that all the currents set in all optical elements of the simulated column can be implemented in the real column (I2TEM in CEMES) and used as starting alignment for the requested experiment. We argue that the combination of such complete electron trajectory simulations in the whole TEM column with automatic optimization of the microscope parameters for optimal experimental data (images, diffraction, spectra) allows drastically simplifying the implementation of complex experiments in TEM and will facilitate the development of advanced use of the electron microscope in the near future. - Highlights: • Using dedicated electron optics software, we calculate full electrons trajectories inside a modern transmission electron microscope. • We have determined how to deal with multi-scale electron optics elements like high voltage cold field emission source. • W • e have succeed to model both weak and strong magnetic lenses whether in saturated or unsaturated conditions as well as electrostatic biprism and magnetic deflectors. • We have applied this model

  7. Self-labelling enzymes as universal tags for fluorescence microscopy, super-resolution microscopy and electron microscopy

    Science.gov (United States)

    Liss, Viktoria; Barlag, Britta; Nietschke, Monika; Hensel, Michael

    2015-01-01

    Research in cell biology demands advanced microscopy techniques such as confocal fluorescence microscopy (FM), super-resolution microscopy (SRM) and transmission electron microscopy (TEM). Correlative light and electron microscopy (CLEM) is an approach to combine data on the dynamics of proteins or protein complexes in living cells with the ultrastructural details in the low nanometre scale. To correlate both data sets, markers functional in FM, SRM and TEM are required. Genetically encoded markers such as fluorescent proteins or self-labelling enzyme tags allow observations in living cells. Various genetically encoded tags are available for FM and SRM, but only few tags are suitable for CLEM. Here, we describe the red fluorescent dye tetramethylrhodamine (TMR) as a multimodal marker for CLEM. TMR is used as fluorochrome coupled to ligands of genetically encoded self-labelling enzyme tags HaloTag, SNAP-tag and CLIP-tag in FM and SRM. We demonstrate that TMR can additionally photooxidize diaminobenzidine (DAB) to an osmiophilic polymer visible on TEM sections, thus being a marker suitable for FM, SRM and TEM. We evaluated various organelle markers with enzymatic tags in mammalian cells labelled with TMR-coupled ligands and demonstrate the use as efficient and versatile DAB photooxidizer for CLEM approaches. PMID:26643905

  8. Scanning electron microscopy and transmission electron microscopy study of hot-deformed gamma-TiAl-based alloy microstructure.

    Science.gov (United States)

    Chrapoński, J; Rodak, K

    2006-09-01

    The aim of this work was to assess the changes in the microstructure of hot-deformed specimens made of alloys containing 46-50 at.% Al, 2 at.% Cr and 2 at.% Nb (and alloying additions such as carbon and boron) with the aid of scanning electron microscopy and transmission electron microscopy techniques. After homogenization and heat treatment performed in order to make diverse lamellae thickness, the specimens were compressed at 1000 degrees C. Transmission electron microscopy examinations of specimens after the compression test revealed the presence of heavily deformed areas with a high density of dislocation. Deformation twins were also observed. Dynamically recrystallized grains were revealed. For alloys no. 2 and no. 3, the recovery and recrystallization processes were more extensive than for alloy no. 1.

  9. A direct electron detector for time-resolved MeV electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Vecchione, T.; Denes, P.; Jobe, R. K.; Johnson, I. J.; Joseph, J. M.; Li, R. K.; Perazzo, A.; Shen, X.; Wang, X. J.; Weathersby, S. P.; Yang, J.; Zhang, D.

    2017-03-01

    The introduction of direct electron detectors enabled the structural biology revolution of cryogenic electron microscopy. Direct electron detectors are now expected to have a similarly dramatic impact on time-resolved MeV electron microscopy, particularly by enabling both spatial and temporal jitter correction. Here we report on the commissioning of a direct electron detector for time-resolved MeV electron microscopy. The direct electron detector demonstrated MeV single electron sensitivity and is capable of recording megapixel images at 180 Hz. The detector has a 15-bit dynamic range, better than 30-μmμm spatial resolution and less than 20 analogue-to-digital converter count RMS pixel noise. The unique capabilities of the direct electron detector and the data analysis required to take advantage of these capabilities are presented. The technical challenges associated with generating and processing large amounts of data are also discussed.

  10. Transmission electron microscopy of the preclinical phase of experimental phytophotodermatitis

    Directory of Open Access Journals (Sweden)

    Hiram Larangeira de Almeida Jr

    2008-01-01

    Full Text Available OBJECTIVE: To examine the epidermis in induced phytophotodermatitis using transmission electron microscopy in order to detect histologic changes even before lesions are visible by light microscopy. INTRODUCTION: In the first six hours after the experimental induction of phytophotodermatitis, no changes are detectable by light microscopy. Only after 24 hours can keratinocyte necrosis and epidermal vacuolization be detected histologically, and blisters form by 48 hours. METHODS: The dorsum of four adult rats (Rattus norvegicus was manually epilated. After painting the right half of the rat with the peel juice of Tahiti lemon, they were exposed to sunlight for eight minutes under general anesthesia. The left side was used as the control and exposed to sunlight only. Biopsies were performed immediately after photoinduction and one and two hours later, and the tissue was analyzed by transmission electron microscopy. RESULTS: No histological changes were seen on the control side. Immediately after induction, vacuolization in keratinocytes was observed. After one hour, desmosomal changes were also observed in addition to vacuolization. Keratin filaments were not attached to the desmosomal plaque. Free desmosomes and membrane ruptures were also seen. At two hours after induction, similar changes were found, and granular degeneration of keratin was also observed. DISCUSSION: The interaction of sunlight and psoralens generates a photoproduct that damages keratinocyte proteins, leading to keratinocyte necrosis and blister formation. CONCLUSIONS: Transmission electron microscopy can detect vacuolization, lesions of the membrane, and desmosomes in the first two hours after experimental induction of phytophotodermatitis.

  11. Light and electron microscopy of classical Ehlers-Danlos syndrome.

    Science.gov (United States)

    de Almeida, Hiram L; Bicca, Eduardo; Rocha, Nara M; de Castro, Luis A S

    2013-02-01

    A 12-year-old boy with difficulty in wound healing and abnormal scars since early childhood was examined. Light microscopy showed loose and disperse dermal collagen with rare bundles, and fibroblasts show an irregular morphology. The fibrous sheath of hair presented a normal parallel distribution of the collagen fibers with normal spindle-shaped fibroblasts. Transmission electron microscopy also found disorganized collagen fibers, which were seen in a same field in longitudinal and cross sections. With high magnifications, an amorphous substance was seen near to loose collagen fibers, which showed variable diameters in cross sections. Scanning electron microscopy of the dermis showed disorganized collagen fibers and with higher magnification, important collagen disarrangement was observed with isolated and crossed-over fibers.

  12. Scanning electron microscopy-energy dispersive X-ray spectrometer ...

    African Journals Online (AJOL)

    The distribution of arsenic (As) and cadmium (Cd) in himematsutake was analyzed using scanning electron microscopy-energy dispersive X-ray spectrometer (SEM-EDX). The atomic percentage of the metals was confirmed by inductively coupled plasma-mass spectrometer (ICP-MS). Results show that the accumulation of ...

  13. Collaboration at the Nanoscale: Exploring Viral Genetics with Electron Microscopy

    Science.gov (United States)

    Duboise, S. Monroe; Moulton, Karen D.; Jamison, Jennifer L.

    2009-01-01

    The Maine Science Corps is a project sponsored by the National Science Foundation's (NSF) Graduate Teaching Fellows in K-12 Education (GK-12 ) program. Through this program, the University of Southern Maine's (USM) virology and transmission electron microscopy (TEM) research group provides high school teachers and students in rural areas with…

  14. Automated data collection in single particle electron microscopy

    Science.gov (United States)

    Tan, Yong Zi; Cheng, Anchi; Potter, Clinton S.; Carragher, Bridget

    2016-01-01

    Automated data collection is an integral part of modern workflows in single particle electron microscopy (EM) research. This review surveys the software packages available for automated single particle EM data collection. The degree of automation at each stage of data collection is evaluated, and the capabilities of the software packages are described. Finally, future trends in automation are discussed. PMID:26671944

  15. Scanning electron microscopy of Dermatobia hominis reveals cutaneous anchoring features.

    Science.gov (United States)

    Möhrenschlager, Matthias; Mempel, Martin; Weichenmeier, Ingrid; Engst, Reinhard; Ring, Johannnes; Behrendt, Heidrun

    2007-10-01

    We report the case of a 45-year-old Caucasian woman suffering from cutaneous myiasis. With the use of scanning electron microscopy, we placed special focus on the mechanisms by which Dermatobia hominis can fasten securely within the human skin.

  16. Time-resolved cryo-electron microscopy: Recent progress.

    Science.gov (United States)

    Frank, Joachim

    2017-06-16

    Time-resolved cryo-electron microscopy (cryo-EM) combines the known advantages of single-particle cryo-EM in visualizing molecular structure with the ability to dissect the time progress of a reaction between molecules in vitro. Here some of the recent progress of this methodology and its first biological applications are outlined. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Microfluidic chip for high resolution transmission electron microscopy

    DEFF Research Database (Denmark)

    2013-01-01

    A Microfluidic chip (100) for transmission electron microscopy has a monolithic body (101) with a front side (102) and a back side (103). The monolithic body (101) comprises an opening (104) on the back side (103) extending in a vertical direction from the back side (103) to a membrane (107...

  18. Electron microscopy studies on MoS2 nanocrystals

    DEFF Research Database (Denmark)

    Hansen, Lars Pilsgaard

    Industrial-style MoS2-based hydrotreating catalysts are studied using electron microscopy. The MoS2 nanostructures are imaged with single-atom sensitivity to reveal the catalytically important edge structures. Furthermore, the in-situ formation of MoS2 crystals is imaged for the first time....

  19. Modeling of Image Formation in Cryo-Electron Microscopy

    NARCIS (Netherlands)

    Vulovic, M.

    2013-01-01

    Knowledge of the structure of biological specimens is crucial for understanding life. Cryo-electron microscopy (cryo-EM) permits structural studies of biological specimen at their near-native state. The research performed in this thesis represents one of two subprojects of the FOM industrial

  20. Composition quantification of electron-transparent samples by backscattered electron imaging in scanning electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Müller, E., E-mail: erich.mueller@kit.edu; Gerthsen, D.

    2017-02-15

    The contrast of backscattered electron (BSE) images in scanning electron microscopy (SEM) depends on material parameters which can be exploited for composition quantification if some information on the material system is available. As an example, the In-concentration in thin In{sub x}Ga{sub 1−x}As layers embedded in a GaAs matrix is analyzed in this work. The spatial resolution of the technique is improved by using thin electron-transparent specimens instead of bulk samples. Although the BSEs are detected in a comparably small angular range by an annular semiconductor detector, the image intensity can be evaluated to determine the composition and local thickness of the specimen. The measured intensities are calibrated within one single image to eliminate the influence of the detection and amplification system. Quantification is performed by comparison of experimental and calculated data. Instead of using time-consuming Monte-Carlo simulations, an analytical model is applied for BSE-intensity calculations which considers single electron scattering and electron diffusion. - Highlights: • Sample thickness and composition are quantified by backscattered electron imaging. • A thin sample is used to achieve spatial resolution of few nanometers. • Calculations are carried out with a time-saving electron diffusion model. • Small differences in atomic number and density detected at low electron energies.

  1. Scanning electron microscopy physics of image formation and microanalysis

    CERN Document Server

    Reimer, Ludwig

    1985-01-01

    The aim of this book is to outline the physics of image formation, electron­ specimen interactions, imaging modes, the interpretation of micrographs and the use of quantitative modes "in scanning electron microscopy (SEM). lt forms a counterpart to Transmission Electron Microscopy (Vol. 36 of this Springer Series in Optical Sciences) . The book evolved from lectures delivered at the University of Münster and from a German text entitled Raster-Elektronenmikroskopie (Springer-Verlag), published in collaboration with my colleague Gerhard Pfefferkorn. In the introductory chapter, the principles of the SEM and of electron­ specimen interactions are described, the most important imaging modes and their associated contrast are summarized, and general aspects of eiemental analysis by x-ray and Auger electron emission are discussed. The electron gun and electron optics are discussed in Chap. 2 in order to show how an electron probe of small diameter can be formed, how the elec­ tron beam can be blanked at high fre...

  2. Effective object planes for aberration-corrected transmission electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Yu, R., E-mail: ryu@tsinghua.edu.cn [Beijing National Center for Electron Microscopy and Laboratory of Advanced Materials, Department of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Lentzen, M. [Institute of Solid State Research and Ernst Ruska Centre, Research Centre Juelich, 52425 Juelich (Germany); Zhu, J. [Beijing National Center for Electron Microscopy and Laboratory of Advanced Materials, Department of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China)

    2012-01-15

    In aberration-corrected transmission electron microscopy, the image contrast depends sensitively on the focus value. With the point resolution extended to an information limit of below 0.1 nm, even a focus change of as small as one nanometer could give a significant change in image contrast. Therefore, it is necessary to consider in detail the optimum focus condition in order to take full advantage of aberration-correction. In this study, the thickness dependence of the minimum contrast focus has been investigated by dynamical image simulations for amorphous model structures of carbon, germanium, and tungsten, which were constructed by molecular dynamics simulations. The calculation results show that the minimum contrast focus varies with the object thickness, supporting the use of an effective object plane close to the midplane instead of the exit plane of a sample, as suggested by Bonhomme and Beorchia [J. Phys. D: Appl. Phys. 16, 705 (1983)] and Lentzen [Microscopy and Microanalysis 12, 191 (2006)]. Thus supported particles and wedge-shaped crystals with symmetrical top and bottom surfaces could be imaged at a focus condition independent of the uneven bottom face. Image simulations of crystalline samples as a function of focus and thickness show: for an object thickness of less than 10 nm, the optimum focus condition is matched better if the midplane of the object, instead of the exit plane, is chosen as reference plane. -- Highlights: Black-Right-Pointing-Pointer Stringent focus condition is required for aberration-corrected TEM. Black-Right-Pointing-Pointer Optimum focus should be set with respect to the midplane of a sample. Black-Right-Pointing-Pointer The focus condition could be independent of the lateral position on a wedged sample.

  3. High-resolution low-dose scanning transmission electron microscopy.

    Science.gov (United States)

    Buban, James P; Ramasse, Quentin; Gipson, Bryant; Browning, Nigel D; Stahlberg, Henning

    2010-01-01

    During the past two decades instrumentation in scanning transmission electron microscopy (STEM) has pushed toward higher intensity electron probes to increase the signal-to-noise ratio of recorded images. While this is suitable for robust specimens, biological specimens require a much reduced electron dose for high-resolution imaging. We describe here protocols for low-dose STEM image recording with a conventional field-emission gun STEM, while maintaining the high-resolution capability of the instrument. Our findings show that a combination of reduced pixel dwell time and reduced gun current can achieve radiation doses comparable to low-dose TEM.

  4. Quantitative high-resolution transmission electron microscopy of single atoms.

    Science.gov (United States)

    Gamm, Björn; Blank, Holger; Popescu, Radian; Schneider, Reinhard; Beyer, André; Gölzhäuser, Armin; Gerthsen, Dagmar

    2012-02-01

    Single atoms can be considered as the most basic objects for electron microscopy to test the microscope performance and basic concepts for modeling image contrast. In this work high-resolution transmission electron microscopy was applied to image single platinum, molybdenum, and titanium atoms in an aberration-corrected transmission electron microscope. The atoms are deposited on a self-assembled monolayer substrate that induces only negligible contrast. Single-atom contrast simulations were performed on the basis of Weickenmeier-Kohl and Doyle-Turner form factors. Experimental and simulated image intensities are in quantitative agreement on an absolute intensity scale, which is provided by the vacuum image intensity. This demonstrates that direct testing of basic properties such as form factors becomes feasible.

  5. Practical aspects of monochromators developed for transmission electron microscopy.

    Science.gov (United States)

    Kimoto, Koji

    2014-10-01

    A few practical aspects of monochromators recently developed for transmission electron microscopy are briefly reviewed. The basic structures and properties of four monochromators, a single Wien filter monochromator, a double Wien filter monochromator, an omega-shaped electrostatic monochromator and an alpha-shaped magnetic monochromator, are outlined. The advantages and side effects of these monochromators in spectroscopy and imaging are pointed out. A few properties of the monochromators in imaging, such as spatial or angular chromaticity, are also discussed. © The Author 2014. Published by Oxford University Press on behalf of The Japanese Society of Microscopy.

  6. Digital imaging of stem cells by electron microscopy.

    Science.gov (United States)

    Sathananthan, A Henry; Nottola, Stefania A

    2007-01-01

    This chapter deals with basic techniques of scanning and transmission electron microscopy applicable to stem cell imaging. It is sometimes desirable to characterize the fine structure of embryonic and adult stem cells to supplement the images obtained by phase-contrast and confocal immunofluorescent microscopy to compare with the microstructure of cells and tissues reported in the literature. This would help confirm their true identity whilst defining their surface and internal morphology. The intention is to put a face on stem cells during their differentiation.

  7. Studying atomic structures by aberration-corrected transmission electron microscopy.

    Science.gov (United States)

    Urban, Knut W

    2008-07-25

    Seventy-five years after its invention, transmission electron microscopy has taken a great step forward with the introduction of aberration-corrected electron optics. An entirely new generation of instruments enables studies in condensed-matter physics and materials science to be performed at atomic-scale resolution. These new possibilities are meeting the growing demand of nanosciences and nanotechnology for the atomic-scale characterization of materials, nanosynthesized products and devices, and the validation of expected functions. Equipped with electron-energy filters and electron-energy-loss spectrometers, the new instruments allow studies not only of structure but also of elemental composition and chemical bonding. The energy resolution is about 100 milli-electron volts, and the accuracy of spatial measurements has reached a few picometers. However, understanding the results is generally not straightforward and only possible with extensive quantum-mechanical computer calculations.

  8. An overview on bioaerosols viewed by scanning electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Wittmaack, K. [GSF-National Research Centre for Environment and Health, Institute of Radiation Protection, 85758 Neuherberg (Germany)]. E-mail: wittmaack@gsf.de; Wehnes, H. [GSF-National Research Centre for Environment and Health, Institute of Pathology, 85758 Neuherberg (Germany); Heinzmann, U. [GSF-National Research Centre for Environment and Health, Institute of Pathology, 85758 Neuherberg (Germany); Agerer, R. [Ludwig-Maximilians University Munich, Department Biology, Biodiversity Research: Mycology, Menzinger Stasse 67, 80638 Munich (Germany)

    2005-06-15

    Bioaerosols suspended in ambient air were collected with single-stage impactors at a semiurban site in southern Germany during late summer and early autumn. Sampling was mostly carried out at a nozzle velocity of 35 m/s, corresponding to a minimum aerodynamic diameter (cut-off diameter) of aerosol particles of 0.8 {mu}m. The collected particles, sampled for short periods ({approx}15 min) to avoid pile-up, were characterized by scanning electron microscopy (SEM). The observed bioaerosols include brochosomes, fungal spores, hyphae, insect scales, hairs of plants and, less commonly, bacteria and epicuticular wax. Brochosomes, which serve as a highly water repellent body coating of leafhoppers, are hollow spheroids with diameters around 400 nm, resembling C{sub 60} or footballs (soccer balls). They are usually airborne not as individuals but in the form of large clusters containing up to 10,000 individual species or even more. Various types of spores and scales were observed, but assignment turned out be difficult due to the large number of fungi and insects from which they may have originated. Pollens were observed only once. The absence these presumably elastic particles suggests that they are frequently lost, at the comparatively high velocities, due to bounce-off from the nonadhesive impaction surfaces.

  9. Use of atomic force microscopy and transmission electron microscopy for correlative studies of bacterial capsules.

    Science.gov (United States)

    Stukalov, Oleg; Korenevsky, Anton; Beveridge, Terry J; Dutcher, John R

    2008-09-01

    Bacteria can possess an outermost assembly of polysaccharide molecules, a capsule, which is attached to their cell wall. We have used two complementary, high-resolution microscopy techniques, atomic force microscopy (AFM) and transmission electron microscopy (TEM), to study bacterial capsules of four different gram-negative bacterial strains: Escherichia coli K30, Pseudomonas aeruginosa FRD1, Shewanella oneidensis MR-4, and Geobacter sulfurreducens PCA. TEM analysis of bacterial cells using different preparative techniques (whole-cell mounts, conventional embeddings, and freeze-substitution) revealed capsules for some but not all of the strains. In contrast, the use of AFM allowed the unambiguous identification of the presence of capsules on all strains used in the present study, including those that were shown by TEM to be not encapsulated. In addition, the use of AFM phase imaging allowed the visualization of the bacterial cell within the capsule, with a depth sensitivity that decreased with increasing tapping frequency.

  10. Transmission electron microscopy of polymer blends and block copolymers

    Science.gov (United States)

    Gomez, Enrique Daniel

    -consistent field theory (SCFT). The liquid-like nature of this system at room temperature makes traditional staining methods for the enhancement of contrast ineffective. As an alternative, we take advantage of the large inelastic scattering cross-section of soft materials to generate contrast in zero-loss TEM images. Independent spatially resolved thickness measurements enable quantification of electron scattering. This enabled a comparison between the TEM data and predictions based on SCFT without any adjustable parameters. The second example involves the utilization of energy-filtered transmission electron microscopy (EFTEM) to compute elemental maps by taking advantage of ionization events. Elemental mapping of lithium is used to determine the distribution of salt in nanostructured poly(styrene-block-ethylene oxide) (SEO) copolymer/lithium salt electrolytes. Surprisingly, the concentration of lithium within a poly(ethylene oxide) (PEO) domain is found to be inhomogeneous; the salt is localized to the middle of the channels. Self-consistent field theory simulations suggest that localization of lithium is due to chain stretching at the interface, which increases with molecular weight. EFTEM and SCFT results show that the segregation of lithium salt to the middle of the PEO lamellae is greater for higher molecular weight polymers. This is correlated with the ionic conductivity of the copolymer electrolyte, which is found to show a higher conductivity for thinner lithium lamellae.

  11. Low-energy electron beams through ultra-thin foils, applications for electron microscopy

    NARCIS (Netherlands)

    Van Aken, R.H.

    2005-01-01

    This thesis has discussed two electron microscopy applications that make use of ultra-thin foils: the tunnel junction emitter and the low-energy foil corrector. Both applications have in common that the electron beam is sent through the thin foil at low energy. Part of the electrons will scatter in

  12. Observation of Bacteriophage Ultrastructure by Cryo-electron Microscopy.

    Science.gov (United States)

    Cuervo, Ana; Carrascosa, José L

    2018-01-01

    Transmission Electron Microscopy (TEM) is an ideal method to observe and determine the structure of bacteriophages. From early studies by negative staining to the present atomic structure models derived from cryo-TEM, bacteriophage detection, classification, and structure determination has been mostly done by electron microscopy. Although embedding in metal salts has been a routine method for virus observation for many years, preservation of bacteriophages in a thin layer of fast frozen buffer has proven to be a most convenient preparation method for obtaining images using cryo-electron microscopy (cryo-EM). In this technique, frozen samples are observed at liquid nitrogen temperature and the images are acquired using different recording media. The incorporation of direct electron detectors has been a fundamental step to achieve atomic resolution images of a number of viruses. These projection images can be numerically combined using different approaches to render a three-dimensional model of the virus. For those viral components exhibiting any symmetry, averaging procedures help to render near-atomic resolution structures.

  13. Vibrational and optical spectroscopies integrated with environmental transmission electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Picher, Matthieu; Mazzucco, Stefano [Center for Nanoscale Science and Technology, National Institute of Standards and Technology, Gaithersburg, MD 20899-6203 (United States); Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, MD 20740 (United States); Blankenship, Steve [Center for Nanoscale Science and Technology, National Institute of Standards and Technology, Gaithersburg, MD 20899-6203 (United States); Sharma, Renu, E-mail: renu.sharma@nist.gov [Center for Nanoscale Science and Technology, National Institute of Standards and Technology, Gaithersburg, MD 20899-6203 (United States)

    2015-03-15

    Here, we present a measurement platform for collecting multiple types of spectroscopy data during high-resolution environmental transmission electron microscopy observations of dynamic processes. Such coupled measurements are made possible by a broadband, high-efficiency, free-space optical system. The critical element of the system is a parabolic mirror, inserted using an independent hollow rod and placed below the sample holder which can focus a light on the sample and/or collect the optical response. We demonstrate the versatility of this optical setup by using it to combine in situ atomic-scale electron microscopy observations with Raman spectroscopy. The Raman data is also used to measure the local temperature of the observed sample area. Other applications include, but are not limited to: cathodo- and photoluminescence spectroscopy, and use of the laser as a local, high-rate heating source. - Highlights: • Broadband, high-efficiency design adaptable to other electron microscopes. • Raman spectroscopy integrated with environmental transmission electron microscopy. • Raman spectra peak frequency shifts enable measurement of local sample temperature. • Multiple types of optical spectroscopy enabled, e.g. cathodoluminescence.

  14. Reelin expression in brain endothelial cells: an electron microscopy study.

    Science.gov (United States)

    Perez-Costas, Emma; Fenton, Erin Y; Caruncho, Hector J

    2015-03-24

    Reelin expression and function have been extensively studied in the brain, although its expression has been also reported in other tissues including blood. This raises the possibility that reelin might be able to cross the blood-brain barrier, which could be functionally relevant. Up-to-date no studies have been conducted to assess if reelin is present in the blood-brain barrier, which is mainly constituted by tightly packed endothelial cells. In this report we assessed the expression of reelin in brain capillaries using immunocytochemistry and electron microscopy. At the light microscope, reelin immunolabeling appeared in specific endothelial cells in brain areas that presented abundant diffuse labeling for this protein (e.g., layer I of the cortex, or the stratum lacunosum moleculare of the hippocampus), while it was mostly absent from capillaries in other brain areas (e.g., deeper cortical layers, or the CA1 layer of the hippocampus). As expected, at the electron microscope reelin labeling was observed in neurons of the cortex, where most of the labeling was associated with the rough endoplasmic reticulum. Importantly, reelin was also observed in some endothelial cells located in small capillaries, which confirmed the findings obtained at the light microscope. In these cells, reelin labeling was located primarily in caveolae (i.e., vesicles of transcytosis), and associated with the plasma membrane of the luminal side of endothelial cells. In addition, some scarce labeling was observed in the nuclear membrane. The presence of reelin immunolabeling in brain endothelial cells, and particularly in caveolar vesicles within these cells, suggests that reelin and/or reelin peptides may be able to cross the blood-brain barrier, which could have important physiological, pathological, and therapeutic implications.

  15. An adjustable electron achromat for cathode lens microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Tromp, R.M., E-mail: rtromp@us.ibm.com [IBM T.J. Watson Research Center, 1101 Kitchawan Road, Yorktown Heights, NY 10598 (United States); Leiden Institute of Physics, Kamerlingh Onnes Laboratory, Niels Bohrweg 2, 2333 CA Leiden (Netherlands)

    2015-12-15

    Chromatic aberration correction in light optics began with the invention of a two-color-corrected achromatic crown/flint lens doublet by Chester Moore Hall in 1730. Such color correction is necessary because any single glass shows dispersion (i.e. its index of refraction changes with wavelength), which can be counteracted by combining different glasses with different dispersions. In cathode lens microscopes (such as Photo Electron Emission Microscopy – PEEM) we encounter a similar situation, where the chromatic aberration coefficient of the cathode lens shows strong dispersion, i.e. depends (non-linearly) on the energy with which the electrons leave the sample. Here I show how a cathode lens in combination with an electron mirror can be configured as an adjustable electron achromat. The lens/mirror combination can be corrected at two electron energies by balancing the settings of the electron mirror against the settings of the cathode lens. The achromat can be adjusted to deliver optimum performance, depending on the requirements of a specific experiment. Going beyond the achromat, an apochromat would improve resolution and transmission by a very significant margin. I discuss the requirements and outlook for such a system, which for now remains a wish waiting for fulfilment. - Highlights: • The properties of cathode objective lens plus electron mirror are discussed. • In analogy with light-optical achromats, cathode lens plus mirror can be configured as an electron achromat. • Unlike light optics, the electron achromat can be adjusted to best fulfill experimental requirements.

  16. Cryo-Scanning Electron Microscopy (SEM) and Scanning Transmission Electron Microscopy (STEM)-in-SEM for Bio- and Organo-Mineral Interface Characterization in the Environment.

    Science.gov (United States)

    Wille, Guillaume; Hellal, Jennifer; Ollivier, Patrick; Richard, Annie; Burel, Agnes; Jolly, Louis; Crampon, Marc; Michel, Caroline

    2017-11-16

    Understanding biofilm interactions with surrounding substratum and pollutants/particles can benefit from the application of existing microscopy tools. Using the example of biofilm interactions with zero-valent iron nanoparticles (nZVI), this study aims to apply various approaches in biofilm preparation and labeling for fluorescent or electron microscopy and energy dispersive X-ray spectrometry (EDS) microanalysis for accurate observations. According to the targeted microscopy method, biofilms were sampled as flocs or attached biofilm, submitted to labeling using 4',6-diamidino-2-phenylindol, lectins PNA and ConA coupled to fluorescent dye or gold nanoparticles, and prepared for observation (fixation, cross-section, freezing, ultramicrotomy). Fluorescent microscopy revealed that nZVI were embedded in the biofilm structure as aggregates but the resolution was insufficient to observe individual nZVI. Cryo-scanning electron microscopy (SEM) observations showed nZVI aggregates close to bacteria, but it was not possible to confirm direct interactions between nZVI and cell membranes. Scanning transmission electron microscopy in the SEM (STEM-in-SEM) showed that nZVI aggregates could enter the biofilm to a depth of 7-11 µm. Bacteria were surrounded by a ring of extracellular polymeric substances (EPS) preventing direct nZVI/membrane interactions. STEM/EDS mapping revealed a co-localization of nZVI aggregates with lectins suggesting a potential role of EPS in nZVI embedding. Thus, the combination of divergent microscopy approaches is a good approach to better understand and characterize biofilm/metal interactions.

  17. Contribution of Metal Layer Thickness for Quantitative Backscattered Electron Imaging of Field Emission Scanning Electron Microscopy

    National Research Council Canada - National Science Library

    Kim, Hyonchol; Takei, Hiroyuki; Negishi, Tsutomu; Kudo, Masato; Terazono, Hideyuki; Yasuda, Kenji

    2012-01-01

    ...) imaging in field emission scanning electron microscopy (FE-SEM) were studied to evaluate the potential of using these particles as simultaneously distinguishable labels of target molecules in FE-SEM studies...

  18. Imaging and Quantification of Extracellular Vesicles by Transmission Electron Microscopy.

    Science.gov (United States)

    Linares, Romain; Tan, Sisareuth; Gounou, Céline; Brisson, Alain R

    2017-01-01

    Extracellular vesicles (EVs) are cell-derived vesicles that are present in blood and other body fluids. EVs raise major interest for their diverse physiopathological roles and their potential biomedical applications. However, the characterization and quantification of EVs constitute major challenges, mainly due to their small size and the lack of methods adapted for their study. Electron microscopy has made significant contributions to the EV field since their initial discovery. Here, we describe the use of two transmission electron microscopy (TEM) techniques for imaging and quantifying EVs. Cryo-TEM combined with receptor-specific gold labeling is applied to reveal the morphology, size, and phenotype of EVs, while their enumeration is achieved after high-speed sedimentation on EM grids.

  19. Microfabricated high-bandpass foucault aperture for electron microscopy

    Science.gov (United States)

    Glaeser, Robert; Cambie, Rossana; Jin, Jian

    2014-08-26

    A variant of the Foucault (knife-edge) aperture is disclosed that is designed to provide single-sideband (SSB) contrast at low spatial frequencies but retain conventional double-sideband (DSB) contrast at high spatial frequencies in transmission electron microscopy. The aperture includes a plate with an inner open area, a support extending from the plate at an edge of the open area, a half-circle feature mounted on the support and located at the center of the aperture open area. The radius of the half-circle portion of reciprocal space that is blocked by the aperture can be varied to suit the needs of electron microscopy investigation. The aperture is fabricated from conductive material which is preferably non-oxidizing, such as gold, for example.

  20. Practical aspects of monochromators developed for transmission electron microscopy

    OpenAIRE

    Kimoto, Koji

    2014-01-01

    A few practical aspects of monochromators recently developed for transmission electron microscopy are briefly reviewed. The basic structures and properties of four monochromators, a single Wien filter monochromator, a double Wien filter monochromator, an omega-shaped electrostatic monochromator and an alpha-shaped magnetic monochromator, are outlined. The advantages and side effects of these monochromators in spectroscopy and imaging are pointed out. A few properties of the monochromators in ...

  1. Transmission Electron Microscopy and Diffractometry of Materials (Third Edition)

    OpenAIRE

    Fultz, Brent; Howe, James M.

    2007-01-01

    This book explains concepts of transmission electron microscopy (TEM) and x-ray diffractometry (XRD) that are important for the characterization of materials. The third edition has been updated to cover important technical developments, including the remarkable recent improvement in resolution of the TEM. This edition is not substantially longer than the second, but all chapters have been updated and revised for clarity. A new chapter on high resolution STEM methods has been added. The book e...

  2. Three-dimensional cryo-electron microscopy on intermediate filaments.

    Science.gov (United States)

    Kirmse, Robert; Bouchet-Marquis, Cédric; Page, Cynthia; Hoenger, Andreas

    2010-01-01

    Together with microtubules and actin filaments (F-actin), intermediate filaments (IFs) form the cytoskeleton of metazoan cells. However, unlike the other two entities that are extremely conserved, IFs are much more diverse and are grouped into five different families. In contrast to microtubules and F-actin, IFs do not exhibit a polarity, which may be the reason that no molecular motors travel along them. The molecular structure of IFs is less well resolved than that of the other cytoskeletal systems. This is partially due to their functional variability, tissue-specific expression, and their intrinsic structural properties. IFs are composed mostly of relatively smooth protofibrils formed by antiparallel arranged α-helical coiled-coil bundles flanked by small globular domains at either end. These features make them difficult to study by various electron microscopy methods or atomic force microscopy (AFM). Furthermore, the elongated shape of monomeric or dimeric IF units interferes with the formation of highly ordered three-dimensional (3-D) crystals suitable for atomic resolution crystallography. So far, most of the data we currently have on IF macromolecular structures come from electron microscopy of negatively stained samples, and fragmented α-helical coiled-coil units solved by X-ray diffraction. In addition, AFM allows the observation of the dynamic states of IFs in solution and delivers a new view into the assembly properties of IFs. Here, we discuss the applicability of cryo-electron microscopy (cryo-EM) and cryo-electron tomography (cryo-ET) for the field. Both methods are strongly related and have only recently been applied to IFs. However, cryo-EM revealed distinct new features within IFs that have not been seen before, and cryo-ET adds a 3-D view of IFs revealing the path and number of protofilaments within the various IF assemblies. Copyright © 2010 Elsevier Inc. All rights reserved.

  3. Cryo-Immuno Electron Microscopy of Peroxisomal Marker Proteins.

    Science.gov (United States)

    Mildner, Karina; Zeuschner, Dagmar

    2017-01-01

    Electron microscopy samples processed for cryo-immunogold-labeling need to be gently fixed to keep their antigenicity. Biological material like cultured cells or tissue can be prepared according to the standard Tokuyasu fixation or in a further developed rehydration method based on high-pressure freezing. We will describe here the variant and common steps of both methods in detail and illustrate their potency in the ultrastructural imaging of peroxisomes.

  4. Scanning Electron Microscopy of Cristispira Species in Chesapeake Bay Oysters

    OpenAIRE

    Tall, Ben D.; Nauman, Robert K.

    1981-01-01

    Scanning electron microscopy was employed to observe the physical interactions between Cristispira spp. and the crystalline style of the Chesapeake Bay oyster (Crassostrea virginica Gmelin 1791). Cristispira organisms were found associated with both the inner and outer layers of the posterior two-thirds of the style. The spirochetes possessed blunt-tipped ends, a cell diameter range of 0.6 to 0.8 μm, and distended spirochetal envelopes which followed the contour of the cells. Transmission ele...

  5. In Situ Electron Microscopy of Lactomicroselenium Particles in Probiotic Bacteria

    Directory of Open Access Journals (Sweden)

    Gabor Nagy

    2016-06-01

    Full Text Available Electron microscopy was used to test whether or not (a in statu nascendi synthesized, and in situ measured, nanoparticle size does not differ significantly from the size of nanoparticles after their purification; and (b the generation of selenium is detrimental to the bacterial strains that produce them. Elemental nano-sized selenium produced by probiotic latic acid bacteria was used as a lactomicroselenium (lactomicroSel inhibitor of cell growth in the presence of lactomicroSel, and was followed by time-lapse microscopy. The size of lactomicroSel produced by probiotic bacteria was measured in situ and after isolation and purification. For these measurements the TESLA BS 540 transmission electron microscope was converted from analog (aTEM to digital processing (dTEM, and further to remote-access internet electron microscopy (iTEM. Lactobacillus acidophilus produced fewer, but larger, lactomicroSel nanoparticles (200–350 nm than Lactobacillus casei (L. casei, which generated many, smaller lactomicroSel particles (85–200 nm and grains as a cloudy, less electrodense material. Streptococcus thermophilus cells generated selenoparticles (60–280 nm in a suicidic manner. The size determined in situ in lactic acid bacteria was significantly lower than those measured by scanning electron microscopy after the isolation of lactomicroSel particles obtained from lactobacilli (100–500 nm, but higher relative to those isolated from Streptococcus thermopilus (50–100 nm. These differences indicate that smaller lactomicroSel particles could be more toxic to the producing bacteria themselves and discrepancies in size could have implications with respect to the applications of selenium nanoparticles as prebiotics.

  6. Electron microscopy methods for studying in vivo DNA replication intermediates.

    Science.gov (United States)

    Lopes, Massimo

    2009-01-01

    The detailed understanding of the DNA replication process requires structural insight. The combination of psoralen crosslinking and electron microscopy has been extensively exploited to reveal the fine architecture of in vivo DNA replication intermediates. This approach proved instrumental to uncover the basic mechanisms of DNA duplication, as well as the perturbation of this process by genotoxic treatments. The replication structures need to the stabilized in vivo (by psoralen crosslinking) prior to extraction and enrichment procedures, finally leading to the visualization at the transmission electron microscope. This chapter outlines the procedures required to visualize in vivo replication intermediates of genomic DNA, extracted from budding yeast or cultured mammalian cells.

  7. Advanced Scanning Electron Microscopy and X Ray Microanalysis

    Science.gov (United States)

    Krinsley, David

    This text is the third in a group that evolved from a short course taught annually at Lehigh University, Bethlehem, Pa., since 1972. Chapters on magnetic contrast a nd electron channeling, dropped from the second volume for reasons of space, are included here along with new topics such as image processing. The first seven chapters should be oT value to those geologists interested in scanning electron microscopy (SEM) and microanalysis. Chapters 8 and 9, concerned with specimen preparation for biological SEM a nd cryomicroscopy, make up about one third of the text.

  8. Transmission electron microscopy of a model crystalline organic, theophylline

    Science.gov (United States)

    Cattle, J.; S'ari, M.; Hondow, N.; Abellán, P.; Brown, A. P.; Brydson, R. M. D.

    2015-10-01

    We report on the use of transmission electron microscopy (TEM) to analyse the diffraction patterns of the model crystalline organic theophylline to investigate beam damage in relation to changing accelerating voltage, sample temperature and TEM grid support films. We find that samples deposited on graphene film grids have the longest lifetimes when also held at -190 °C and imaged at 200 kV accelerating voltage. Finally, atomic lattice images are obtained in bright field STEM by working close to the estimated critical electron dose for theophylline.

  9. Electron cryo-microscopy structure of the mechanotransduction channel NOMPC.

    Science.gov (United States)

    Jin, Peng; Bulkley, David; Guo, Yanmeng; Zhang, Wei; Guo, Zhenhao; Huynh, Walter; Wu, Shenping; Meltzer, Shan; Cheng, Tong; Jan, Lily Yeh; Jan, Yuh-Nung; Cheng, Yifan

    2017-07-06

    Mechanosensory transduction for senses such as proprioception, touch, balance, acceleration, hearing and pain relies on mechanotransduction channels, which convert mechanical stimuli into electrical signals in specialized sensory cells. How force gates mechanotransduction channels is a central question in the field, for which there are two major models. One is the membrane-tension model: force applied to the membrane generates a change in membrane tension that is sufficient to gate the channel, as in the bacterial MscL channel and certain eukaryotic potassium channels. The other is the tether model: force is transmitted via a tether to gate the channel. The transient receptor potential (TRP) channel NOMPC is important for mechanosensation-related behaviours such as locomotion, touch and sound sensation across different species including Caenorhabditis elegans, Drosophila and zebrafish. NOMPC is the founding member of the TRPN subfamily, and is thought to be gated by tethering of its ankyrin repeat domain to microtubules of the cytoskeleton. Thus, a goal of studying NOMPC is to reveal the underlying mechanism of force-induced gating, which could serve as a paradigm of the tether model. NOMPC fulfils all the criteria that apply to mechanotransduction channels and has 29 ankyrin repeats, the largest number among TRP channels. A key question is how the long ankyrin repeat domain is organized as a tether that can trigger channel gating. Here we present a de novo atomic structure of Drosophila NOMPC determined by single-particle electron cryo-microscopy. Structural analysis suggests that the ankyrin repeat domain of NOMPC resembles a helical spring, suggesting its role of linking mechanical displacement of the cytoskeleton to the opening of the channel. The NOMPC architecture underscores the basis of translating mechanical force into an electrical signal within a cell.

  10. System and method for compressive scanning electron microscopy

    Science.gov (United States)

    Reed, Bryan W

    2015-01-13

    A scanning transmission electron microscopy (STEM) system is disclosed. The system may make use of an electron beam scanning system configured to generate a plurality of electron beam scans over substantially an entire sample, with each scan varying in electron-illumination intensity over a course of the scan. A signal acquisition system may be used for obtaining at least one of an image, a diffraction pattern, or a spectrum from the scans, the image, diffraction pattern, or spectrum representing only information from at least one of a select subplurality or linear combination of all pixel locations comprising the image. A dataset may be produced from the information. A subsystem may be used for mathematically analyzing the dataset to predict actual information that would have been produced by each pixel location of the image.

  11. Navigating 3D electron microscopy maps with EM-SURFER.

    Science.gov (United States)

    Esquivel-Rodríguez, Juan; Xiong, Yi; Han, Xusi; Guang, Shuomeng; Christoffer, Charles; Kihara, Daisuke

    2015-05-30

    The Electron Microscopy DataBank (EMDB) is growing rapidly, accumulating biological structural data obtained mainly by electron microscopy and tomography, which are emerging techniques for determining large biomolecular complex and subcellular structures. Together with the Protein Data Bank (PDB), EMDB is becoming a fundamental resource of the tertiary structures of biological macromolecules. To take full advantage of this indispensable resource, the ability to search the database by structural similarity is essential. However, unlike high-resolution structures stored in PDB, methods for comparing low-resolution electron microscopy (EM) density maps in EMDB are not well established. We developed a computational method for efficiently searching low-resolution EM maps. The method uses a compact fingerprint representation of EM maps based on the 3D Zernike descriptor, which is derived from a mathematical series expansion for EM maps that are considered as 3D functions. The method is implemented in a web server named EM-SURFER, which allows users to search against the entire EMDB in real-time. EM-SURFER compares the global shapes of EM maps. Examples of search results from different types of query structures are discussed. We developed EM-SURFER, which retrieves structurally relevant matches for query EM maps from EMDB within seconds. The unique capability of EM-SURFER to detect 3D shape similarity of low-resolution EM maps should prove invaluable in structural biology.

  12. Transmission electron microscopy physics of image formation and microanalysis

    CERN Document Server

    Reimer, Ludwig

    1984-01-01

    The aim of this book is to outline the physics of image formation, electron­ specimen interactions and image interpretation in transmission electron mic­ roscopy. The book evolved from lectures delivered at the University of Munster and is a revised version of the first part of my earlier book Elek­ tronenmikroskopische Untersuchungs- und Priiparationsmethoden, omitting the part which describes specimen-preparation methods. In the introductory chapter, the different types of electron microscope are compared, the various electron-specimen interactions and their applications are summarized and the most important aspects of high-resolution, analytical and high-voltage electron microscopy are discussed. The optics of electron lenses is discussed in Chapter 2 in order to bring out electron-lens properties that are important for an understanding of the function of an electron microscope. In Chapter 3, the wave optics of elec­ trons and the phase shifts by electrostatic and magnetic fields are introduced; Fresne...

  13. Axial ion-electron emission microscopy of IC radiation hardness

    Science.gov (United States)

    Doyle, B. L.; Vizkelethy, G.; Walsh, D. S.; Swenson, D.

    2002-05-01

    A new system for performing radiation effects microscopy (REM) has been developed at Sandia National Laboratory in Albuquerque. This system combines two entirely new concepts in accelerator physics and nuclear microscopy. A radio frequency quadrupole (RFQ) linac is used to boost the energy of ions accelerated by a conventional Tandem Van de Graaff-Pelletron to velocities of 1.9 MeV/amu. The electronic stopping power for heavy ions is near a maximum at this velocity, and their range is ˜20 μm in Si. These ions therefore represent the most ionizing form of radiation in nature, and are nearly ideal for performing single event effects testing of integrated circuits. Unfortunately, the energy definition of the RFQ-boosted ions is rather poor (˜ a few %), which makes problematic the focussing of such ions to the submicron spots required for REM. To circumvent this problem, we have invented ion electron emission microscopy (IEEM). One can perform REM with the IEEM system without focussing or scanning the ion beam. This is because the position on the sample where each ion strikes is determined by projecting ion-induced secondary electrons at high magnification onto a single electron position sensitive detector. This position signal is then correlated with each REM event. The IEEM system is now mounted along the beam line in an axial geometry so that the ions pass right through the electron detector (which is annular), and all of the electrostatic lenses used for projection. The beam then strikes the sample at normal incidence which results in maximum ion penetration and removes a parallax problem experienced in an earlier system. Details of both the RFQ-booster and the new axial IEEM system are given together with some of the initial results of performing REM on Sandia-manufactured radiation hardened integrated circuits.

  14. Further observations on cerebellar climbing fibers. A study by means of light microscopy, confocal laser scanning microscopy and scanning and transmission electron microscopy.

    Science.gov (United States)

    Castejón, O J; Castejón, H V; Alvarado, M V

    2000-12-01

    The intracortical pathways of climbing fibers were traced in several vertebrate cerebella using light microscopy, confocal laser scanning microscopy, scanning and transmission electron microscopy. They were identified as fine fibers up to 1(micron thick, with a characteristic crossing-over bifurcation pattern. Climbing fiber collaterals were tridimensionally visualized forming thin climbing fiber glomeruli in the granular layer. Confocal laser scanning microscopy revealed three types of collateral processes at the interface between granular and Purkinje cell layers. Scanning electron microscopy showed climbing fiber retrograde collaterals in the molecular layer. Asymmetric synaptic contacts of climbing fibers with Purkinje dendritic spines and stellate neuron dendrites were characterized by transmission electron microscopy. Correlative microscopy allowed us to obtain the basic three-dimensional morphological features of climbing fibers in several vertebrates and to show with more accuracy a higher degree of lateral collateralization of these fibers within the cerebellar cortex. The correlative microscopy approach provides new views in the cerebellar cortex information processing.

  15. Correlative cryo-electron tomography and optical microscopy of cells.

    Science.gov (United States)

    Zhang, Peijun

    2013-10-01

    The biological processes occurring in a cell are complex and dynamic, and to achieve a comprehensive understanding of the molecular mechanisms underlying these processes, both temporal and spatial information is required. While cryo-electron tomography (cryoET) provides three-dimensional (3D) still pictures of near-native state cells and organelles at molecular resolution, fluorescence light microscopy (fLM) offers movies of dynamic cellular processes in living cells. Combining and integrating these two commonly used imaging modalities (termed correlative microscopy) provides a powerful means to not only expand the imaging scale and resolution but also to complement the dynamic information available from optical microscopy with the molecular-level, 3D ultrastructure detail provided by cryoET. As such, a correlative approach performed on a given specimen can provide high resolution snapshots of dynamic cellular events. In this article, I review recent advances in correlative light microscopy and cryoET and discuss major findings made available by applying this method. Copyright © 2013 Elsevier Ltd. All rights reserved.

  16. Big Data Analytics for Scanning Transmission Electron Microscopy Ptychography

    Science.gov (United States)

    Jesse, S.; Chi, M.; Belianinov, A.; Beekman, C.; Kalinin, S. V.; Borisevich, A. Y.; Lupini, A. R.

    2016-05-01

    Electron microscopy is undergoing a transition; from the model of producing only a few micrographs, through the current state where many images and spectra can be digitally recorded, to a new mode where very large volumes of data (movies, ptychographic and multi-dimensional series) can be rapidly obtained. Here, we discuss the application of so-called “big-data” methods to high dimensional microscopy data, using unsupervised multivariate statistical techniques, in order to explore salient image features in a specific example of BiFeO3 domains. Remarkably, k-means clustering reveals domain differentiation despite the fact that the algorithm is purely statistical in nature and does not require any prior information regarding the material, any coexisting phases, or any differentiating structures. While this is a somewhat trivial case, this example signifies the extraction of useful physical and structural information without any prior bias regarding the sample or the instrumental modality. Further interpretation of these types of results may still require human intervention. However, the open nature of this algorithm and its wide availability, enable broad collaborations and exploratory work necessary to enable efficient data analysis in electron microscopy.

  17. Big Data Analytics for Scanning Transmission Electron Microscopy Ptychography.

    Science.gov (United States)

    Jesse, S; Chi, M; Belianinov, A; Beekman, C; Kalinin, S V; Borisevich, A Y; Lupini, A R

    2016-05-23

    Electron microscopy is undergoing a transition; from the model of producing only a few micrographs, through the current state where many images and spectra can be digitally recorded, to a new mode where very large volumes of data (movies, ptychographic and multi-dimensional series) can be rapidly obtained. Here, we discuss the application of so-called "big-data" methods to high dimensional microscopy data, using unsupervised multivariate statistical techniques, in order to explore salient image features in a specific example of BiFeO3 domains. Remarkably, k-means clustering reveals domain differentiation despite the fact that the algorithm is purely statistical in nature and does not require any prior information regarding the material, any coexisting phases, or any differentiating structures. While this is a somewhat trivial case, this example signifies the extraction of useful physical and structural information without any prior bias regarding the sample or the instrumental modality. Further interpretation of these types of results may still require human intervention. However, the open nature of this algorithm and its wide availability, enable broad collaborations and exploratory work necessary to enable efficient data analysis in electron microscopy.

  18. Introduction to high-resolution cryo-electron microscopy.

    Science.gov (United States)

    Czarnocki-Cieciura, Mariusz; Nowotny, Marcin

    For many years two techniques have dominated structural biology - X-ray crystallography and NMR spectroscopy. Traditional cryo-electron microscopy of biological macromolecules produced macromolecular reconstructions at resolution limited to 6-10 Å. Recent development of transmission electron microscopes, in particular the development of direct electron detectors, and continuous improvements in the available software, have led to the "resolution revolution" in cryo-EM. It is now possible to routinely obtain near-atomic-resolution 3D maps of intact biological macromolecules as small as ~100 kDa. Thus, cryo-EM is now becoming the method of choice for structural analysis of many complex assemblies that are unsuitable for structure determination by other methods.

  19. Investigation of Nematode Diversity using Scanning Electron Microscopy and Fluorescent Microscopy

    Science.gov (United States)

    Seacor, Taylor; Howell, Carina

    2013-03-01

    Nematode worms account for the vast majority of the animals in the biosphere. They are colossally important to global public health as parasites, and to agriculture both as pests and as beneficial inhabitants of healthy soil. Amphid neurons are the anterior chemosensory neurons in nematodes, mediating critical behaviors including chemotaxis and mating. We are examining the cellular morphology and external anatomy of amphid neurons, using fluorescence microscopy and scanning electron microscopy, respectively, of a wide range of soil nematodes isolated in the wild. We use both classical systematics (e.g. diagnostic keys) and molecular markers (e.g. ribosomal RNA) to classify these wild isolates. Our ultimate aim is to build a detailed anatomical database in order to dissect genetic pathways of neuronal development and function across phylogeny and ecology. Research supported by NSF grants 092304, 0806660, 1058829 and Lock Haven University FPDC grants

  20. Electron microscopy of primary cell cultures in solution and correlative optical microscopy using ASEM

    Energy Technology Data Exchange (ETDEWEB)

    Hirano, Kazumi; Kinoshita, Takaaki [Laboratory of Cell Biology, Department of Bioinformatics, Faculty of Engineering, Soka University, 1-236 Tangi-machi, Hachioji, Tokyo 192-8577 (Japan); Uemura, Takeshi [Department of Molecular Neurobiology and Pharmacology, Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Department of Molecular and Cellular Physiology, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto, Nagano 390-8621 (Japan); Motohashi, Hozumi [Department of Gene Expression Regulation, Institute of Development, Aging and Cancer, Tohoku University, 4-1 Seiryo-cho, Aoba-ku, Sendai 980-8575 (Japan); Watanabe, Yohei; Ebihara, Tatsuhiko [Biomedical Research Institute, National Institute of Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba 305-8566 (Japan); Nishiyama, Hidetoshi [JEOL Ltd., 1-2 Musashino 3-chome, Akishima, Tokyo 196-8558 (Japan); Sato, Mari [Biomedical Research Institute, National Institute of Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba 305-8566 (Japan); Suga, Mitsuo [JEOL Ltd., 1-2 Musashino 3-chome, Akishima, Tokyo 196-8558 (Japan); Maruyama, Yuusuke; Tsuji, Noriko M. [Biomedical Research Institute, National Institute of Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba 305-8566 (Japan); Yamamoto, Masayuki [Department of Medical Biochemistry, Tohoku University Graduate School of Medicine, 2-1 Seiryo-cho, Aoba-ku, Sendai 980-8575 (Japan); Nishihara, Shoko, E-mail: shoko@soka.ac.jp [Laboratory of Cell Biology, Department of Bioinformatics, Faculty of Engineering, Soka University, 1-236 Tangi-machi, Hachioji, Tokyo 192-8577 (Japan); Sato, Chikara, E-mail: ti-sato@aist.go.jp [Biomedical Research Institute, National Institute of Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba 305-8566 (Japan)

    2014-08-01

    Correlative light-electron microscopy of cells in a natural environment of aqueous liquid facilitates high-throughput observation of protein complex formation. ASEM allows the inverted SEM to observe the wet sample from below, while an optical microscope observes it from above quasi-simultaneously. The disposable ASEM dish with a silicon nitride (SiN) film window can be coated variously to realize the primary-culture of substrate-sensitive cells in a few milliliters of culture medium in a stable incubator environment. Neuron differentiation, neural networking, proplatelet-formation and phagocytosis were captured by optical or fluorescence microscopy, and imaged at high resolution by gold-labeled immuno-ASEM with/without metal staining. Fas expression on the cell surface was visualized, correlated to the spatial distribution of F-actin. Axonal partitioning was studied using primary-culture neurons, and presynaptic induction by GluRδ2-N-terminus-linked fluorescent magnetic beads was correlated to the presynaptic-marker Bassoon. Further, megakaryocytes secreting proplatelets were captured, and P-selectins with adherence activity were localized to some of the granules present by immuno-ASEM. The phagocytosis of lactic acid bacteria by dendritic cells was also imaged. Based on these studies, ASEM correlative microscopy promises to allow the study of various mesoscopic-scale dynamics in the near future. - Highlights: • In situ correlative light electron microscopy of samples in open solution by ASEM. • Primary cultures for in-solution CLEM by developing SiN-film coating methods • First visualization of fluorescent magnetic beads in aqueous solution by CLEM. • Presynaptic induction of neurons by GluRδ2-N-terminus-coated beads studied by CLEM. • Axonal partitioning, bacterial phagocytosis, platelet formation imaged by CLEM.

  1. Electron microscopy imaging of proteins on gallium phosphide semiconductor nanowires

    Science.gov (United States)

    Hjort, Martin; Bauer, Mikael; Gunnarsson, Stefan; Mårsell, Erik; Zakharov, Alexei A.; Karlsson, Gunnel; Sanfins, Elodie; Prinz, Christelle N.; Wallenberg, Reine; Cedervall, Tommy; Mikkelsen, Anders

    2016-02-01

    We have imaged GaP nanowires (NWs) incubated with human laminin, serum albumin (HSA), and blood plasma using both cryo-transmission electron microscopy and synchrotron based X-ray photoemission electron microscopy. This extensive imaging methodology simultaneously reveals structural, chemical and morphological details of individual nanowires and the adsorbed proteins. We found that the proteins bind to NWs, forming coronas with thicknesses close to the proteins' hydrodynamic diameters. We could directly image how laminin is extending from the NWs, maximizing the number of proteins bound to the NWs. NWs incubated with both laminin and HSA show protein coronas with a similar appearance to NWs incubated with laminin alone, indicating that the presence of HSA does not affect the laminin conformation on the NWs. In blood plasma, an intermediate sized corona around the NWs indicates a corona with a mixture of plasma proteins. The ability to directly visualize proteins on nanostructures in situ holds great promise for assessing the conformation and thickness of the protein corona, which is key to understanding and predicting the properties of engineered nanomaterials in a biological environment.We have imaged GaP nanowires (NWs) incubated with human laminin, serum albumin (HSA), and blood plasma using both cryo-transmission electron microscopy and synchrotron based X-ray photoemission electron microscopy. This extensive imaging methodology simultaneously reveals structural, chemical and morphological details of individual nanowires and the adsorbed proteins. We found that the proteins bind to NWs, forming coronas with thicknesses close to the proteins' hydrodynamic diameters. We could directly image how laminin is extending from the NWs, maximizing the number of proteins bound to the NWs. NWs incubated with both laminin and HSA show protein coronas with a similar appearance to NWs incubated with laminin alone, indicating that the presence of HSA does not affect the

  2. Ultrahigh Voltage Electron Microscopy Links Neuroanatomy and Neuroscience/Neuroendocrinology

    Directory of Open Access Journals (Sweden)

    Hirotaka Sakamoto

    2012-01-01

    Full Text Available The three-dimensional (3D analysis of anatomical ultrastructures is extremely important in most fields of biological research. Although it is very difficult to perform 3D image analysis on exact serial sets of ultrathin sections, 3D reconstruction from serial ultrathin sections can generally be used to obtain 3D information. However, this technique can only be applied to small areas of a specimen because of technical and physical difficulties. We used ultrahigh voltage electron microscopy (UHVEM to overcome these difficulties and to study the chemical neuroanatomy of 3D ultrastructures. This methodology, which links UHVEM and light microscopy, is a useful and powerful tool for studying molecular and/or chemical neuroanatomy at the ultrastructural level.

  3. Signatures of plasmoemission in two photon photoemission electron microscopy

    Science.gov (United States)

    Meyer zu Heringdorf, Frank-J.; Kahl, Philip; Makris, Andreas; Sindermann, Simon; Podbiel, Daniel; Horn-von Hoegen, Michael

    2015-03-01

    The imaging of surface plasmon polariton waves in two photon photoemission microscopy has been intensely studied during the past years, with a focus on contrast mechanisms and light-plasmon interaction. The possibility of photoemission from the plasmonic fields alone has so far not been addressed in such experiments. This was justified, since the intensity of the plasmonic fields at the surface was comparatively weak and nonlinear plasmonic effects were not to be expected. Here we discuss the properties of grating couplers for creation of intense and short plasmon polariton pulses for which the emission of electrons purely from the plasmonic field cannot be neglected any more. Two examples for signatures of such nonlinear plasmoemission effects in experimental two photon photoemission microscopy images are discussed.

  4. Single-particle cryo-electron microscopy of macromolecular complexes.

    Science.gov (United States)

    Skiniotis, Georgios; Southworth, Daniel R

    2016-02-01

    Recent technological breakthroughs in image acquisition have enabled single-particle cryo-electron microscopy (cryo-EM) to achieve near-atomic resolution structural information for biological complexes. The improvements in image quality coupled with powerful computational methods for sorting distinct particle populations now also allow the determination of compositional and conformational ensembles, thereby providing key insights into macromolecular function. However, the inherent instability and dynamic nature of biological assemblies remain a tremendous challenge that often requires tailored approaches for successful implementation of the methodology. Here, we briefly describe the fundamentals of single-particle cryo-EM with an emphasis on covering the breadth of techniques and approaches, including low- and high-resolution methods, aiming to illustrate specific steps that are crucial for obtaining structural information by this method. © The Author 2015. 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.

  5. Electron microscopy of flatworms standard and cryo-preparation methods.

    Science.gov (United States)

    Salvenmoser, Willi; Egger, Bernhard; Achatz, Johannes G; Ladurner, Peter; Hess, Michael W

    2010-01-01

    Electron microscopy (EM) has long been indispensable for flatworm research, as most of these worms are microscopic in dimension and provide only a handful of characters recognizable by eye or light microscopy. Therefore, major progress in understanding the histology, systematics, and evolution of this animal group relied on methods capable of visualizing ultrastructure. The rise of molecular and cellular biology renewed interest in such ultrastructural research. In the light of recent developments, we offer a best-practice guide for users of transmission EM and provide a comparison of well-established chemical fixation protocols with cryo-processing methods (high-pressure freezing/freeze-substitution, HPF/FS). The organisms used in this study include the rhabditophorans Macrostomum lignano, Polycelis nigra and Dugesia gonocephala, as well as the acoel species Isodiametra pulchra. Copyright © 2010 Elsevier Inc. All rights reserved.

  6. High-resolution electron microscopy of advanced materials

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, T.E.; Kung, H.H.; Sickafus, K.E.; Gray, G.T. III; Field, R.D.; Smith, J.F. [Los Alamos National Lab., NM (United States). Materials Science and Technology Div.

    1997-11-01

    This final report chronicles a three-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). The High-Resolution Electron Microscopy Facility has doubled in size and tripled in quality since the beginning of the three-year period. The facility now includes a field-emission scanning electron microscope, a 100 kV field-emission scanning transmission electron microscope (FE-STEM), a 300 kV field-emission high-resolution transmission electron microscope (FE-HRTEM), and a 300 kV analytical transmission electron microscope. A new orientation imaging microscope is being installed. X-ray energy dispersive spectrometers for chemical analysis are available on all four microscopes; parallel electron energy loss spectrometers are operational on the FE-STEM and FE-HRTEM. These systems enable evaluation of local atomic bonding, as well as chemical composition in nanometer-scale regions. The FE-HRTEM has a point-to-point resolution of 1.6 {angstrom}, but the resolution can be pushed to its information limit of 1 {angstrom} by computer reconstruction of a focal series of images. HRTEM has been used to image the atomic structure of defects such as dislocations, grain boundaries, and interfaces in a variety of materials from superconductors and ferroelectrics to structural ceramics and intermetallics.

  7. Generation and application of bessel beams in electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Grillo, Vincenzo, E-mail: vincenzo.grillo@cnr.it [CNR-Istituto Nanoscienze, Centro S3, Via G Campi 213/a, I-41125 Modena (Italy); CNR-IMEM, Parco Area delle Scienze 37/A, I-43124 Parma (Italy); Harris, Jérémie [Department of Physics, University of Ottawa, 25 Templeton St., Ottawa, Ontario, Canada K1N 6N5 (Canada); Gazzadi, Gian Carlo [CNR-Istituto Nanoscienze, Centro S3, Via G Campi 213/a, I-41125 Modena (Italy); Balboni, Roberto [CNR-IMM Bologna, Via P. Gobetti 101, 40129 Bologna (Italy); Mafakheri, Erfan [Dipartimento di Fisica Informatica e Matematica, Università di Modena e Reggio Emilia, via G Campi 213/a, I-41125 Modena (Italy); Dennis, Mark R. [H.H. Wills Physics Laboratory, University of Bristol, Bristol BS8 1TL (United Kingdom); Frabboni, Stefano [CNR-Istituto Nanoscienze, Centro S3, Via G Campi 213/a, I-41125 Modena (Italy); Dipartimento di Fisica Informatica e Matematica, Università di Modena e Reggio Emilia, via G Campi 213/a, I-41125 Modena (Italy); Boyd, Robert W.; Karimi, Ebrahim [Department of Physics, University of Ottawa, 25 Templeton St., Ottawa, Ontario, Canada K1N 6N5 (Canada)

    2016-07-15

    We report a systematic treatment of the holographic generation of electron Bessel beams, with a view to applications in electron microscopy. We describe in detail the theory underlying hologram patterning, as well as the actual electron-optical configuration used experimentally. We show that by optimizing our nanofabrication recipe, electron Bessel beams can be generated with relative efficiencies reaching 37±3%. We also demonstrate by tuning various hologram parameters that electron Bessel beams can be produced with many visible rings, making them ideal for interferometric applications, or in more highly localized forms with fewer rings, more suitable for imaging. We describe the settings required to tune beam localization in this way, and explore beam and hologram configurations that allow the convergences and topological charges of electron Bessel beams to be controlled. We also characterize the phase structure of the Bessel beams generated with our technique, using a simulation procedure that accounts for imperfections in the hologram manufacturing process. - Highlights: • Bessel beams with different convergence, topological charge, visible fringes are demonstrated. • The relation between the Fresnel hologram and the probe shape is explained by detailed calculations and experiments. • Among the holograms here presented the highest relative efficiency is 37%, the best result ever reached for blazed holograms.

  8. Three-Dimensional scanning transmission electron microscopy of biological specimens

    KAUST Repository

    De Jonge, Niels

    2010-01-18

    A three-dimensional (3D) reconstruction of the cytoskeleton and a clathrin-coated pit in mammalian cells has been achieved from a focal-series of images recorded in an aberration-corrected scanning transmission electron microscope (STEM). The specimen was a metallic replica of the biological structure comprising Pt nanoparticles 2-3 nm in diameter, with a high stability under electron beam radiation. The 3D dataset was processed by an automated deconvolution procedure. The lateral resolution was 1.1 nm, set by pixel size. Particles differing by only 10 nm in vertical position were identified as separate objects with greater than 20% dip in contrast between them. We refer to this value as the axial resolution of the deconvolution or reconstruction, the ability to recognize two objects, which were unresolved in the original dataset. The resolution of the reconstruction is comparable to that achieved by tilt-series transmission electron microscopy. However, the focal-series method does not require mechanical tilting and is therefore much faster. 3D STEM images were also recorded of the Golgi ribbon in conventional thin sections containing 3T3 cells with a comparable axial resolution in the deconvolved dataset. © 2010 Microscopy Society of America.

  9. Resinless section electron microscopy reveals the yeast cytoskeleton.

    Science.gov (United States)

    Penman, J; Penman, S

    1997-04-15

    The cytoskeleton of Saccharomyces cerevisiae is essentially invisible using conventional microscopy techniques. A similar problem was solved for the mammalian cell cytoskeleton using resinless section electron microscopy, a technique applied here to yeast. In the resinless image, soluble proteins are no longer cloaked by embedding medium and must be removed by selective detergent extraction. In yeast, this requires breaching the cell wall by digesting with Zymolyase sufficiently to allow detergent extraction of the plasma membrane lipids. Gel electropherograms show that the extracted or "soluble" proteins are distinct from the retained or "structural" proteins that presumably comprise the cytoskeleton. These putative cytoskeleton proteins include the major portions of a 43-kDa protein, which is presumably actin, and of proteins in a band appearing at 55 kDa, as well as numerous less abundant, nonactin proteins. Resinless section electron micrographs show a dense, three-dimensional web of anastomosing, polymorphic filaments bounded by the remnant cell wall. Although the filament network is very heterogenous, there appear to be two principal classes of filament diameters-5 nm and 15-20 nm-which may correspond to actin and intermediate filaments, respectively. A large oval region of lower filament density probably corresponds to the vacuole, and an electron dense spheroidal body, 300-500 nm in diameter, is likely the nucleus. The techniques detailed in this report afford new approaches to the study of yeast cytoarchitecture.

  10. Rapid detection of intracellular nanoparticles by electron microscopy

    Directory of Open Access Journals (Sweden)

    Kyoung Hwan Lee

    2010-03-01

    Full Text Available Recently, a number of nanoparticle carriers have provided new platforms for research in biotechnology and biomedicine. A particularly interest in these fields is the monitoring of nanoparticle delivery to target cells. Since the structures involved are on a nanometer scale, high resolution imaging, such as electron microscopy, is required. Aside from assessing the structural characteristics of the target sites localized with the nanoparticles, an electron microscope can also be used to observe the biological effects of the nanoparticles on the cells. It can also be used to test and detect a wide range of fluorescent nanoparticles and nanoassemblies. Although this approach has many advantages, most researchers are unwilling to try electron microscopy due to the complicated specimen preparation procedures and time-consuming process. Here, we developed a method to simplify the sample preparation and shorten the total processing time. In particular, double staining was removed, and cryo-preparation was included. Using this simple and rapid sample preparation, we were able to observe nanoparticles with high-contrast images of the cellular organelles. This efficient detection method can be applied to studies on nanoparticle drug delivery systems and nanoparticle-cell interactions.

  11. Aberration-Coreected Electron Microscopy at Brookhaven National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Zhu,Y.; Wall, J.

    2008-04-01

    The last decade witnessed the rapid development and implementation of aberration correction in electron optics, realizing a more-than-70-year-old dream of aberration-free electron microscopy with a spatial resolution below one angstrom [1-9]. With sophisticated aberration correctors, modern electron microscopes now can reveal local structural information unavailable with neutrons and x-rays, such as the local arrangement of atoms, order/disorder, electronic inhomogeneity, bonding states, spin configuration, quantum confinement, and symmetry breaking [10-17]. Aberration correction through multipole-based correctors, as well as the associated improved stability in accelerating voltage, lens supplies, and goniometers in electron microscopes now enables medium-voltage (200-300kV) microscopes to achieve image resolution at or below 0.1nm. Aberration correction not only improves the instrument's spatial resolution but, equally importantly, allows larger objective lens pole-piece gaps to be employed thus realizing the potential of the instrument as a nanoscale property-measurement tool. That is, while retaining high spatial resolution, we can use various sample stages to observe the materials response under various temperature, electric- and magnetic- fields, and atmospheric environments. Such capabilities afford tremendous opportunities to tackle challenging science and technology issues in physics, chemistry, materials science, and biology. The research goal of the electron microscopy group at the Dept. of Condensed Matter Physics and Materials Science and the Center for Functional Nanomaterials, as well as the Institute for Advanced Electron Microscopy, Brookhaven National Laboratory (BNL), is to elucidate the microscopic origin of the physical- and chemical-behavior of materials, and the role of individual, or groups of atoms, especially in their native functional environments. We plan to accomplish this by developing and implementing various quantitative

  12. Neuron Segmentation in Electron Microscopy Images Using Partial Differential Equations.

    Science.gov (United States)

    Jones, Cory; Sayedhosseini, Mojtaba; Ellisman, Mark; Tasdizen, Tolga

    2013-01-01

    In connectomics, neuroscientists seek to identify the synaptic connections between neurons. Segmentation of cell membranes using supervised learning algorithms on electron microscopy images of brain tissue is often done to assist in this effort. Here we present a partial differential equation with a novel growth term to improve the results of a supervised learning algorithm. We also introduce a new method for representing the resulting image that allows for a more dynamic thresholding to further improve the result. Using these two processes we are able to close small to medium sized gaps in the cell membrane detection and improve the Rand error by as much as 9% over the initial supervised segmentation.

  13. Evaluation of the bleached human enamel by Scanning Electron Microscopy

    DEFF Research Database (Denmark)

    Miranda, Carolina Baptista; Pagani, Clovis; Benetti, Ana Raquel

    2005-01-01

    Since bleaching has become a popular procedure, the effect of peroxides on dental hard tissues is of great interest in research. Purpose: The aim of this in vitro study was to perform a qualitative analysis of the human enamel after the application of in-office bleaching agents, using Scanning...... Electron Microscopy (SEM). Materials and Methods: Twenty intact human third molars extracted for orthodontic reasons were randomly divided into four groups (n=5) treated as follows: G1- storage in artificial saliva (control group); G2- four 30-minute applications of 35% carbamide peroxide (total exposure...

  14. Structural studies of T4S systems by electron microscopy

    Directory of Open Access Journals (Sweden)

    Adam Redzej

    2015-06-01

    Full Text Available Type IV secretion (T4S systems are large dynamic nanomachines that transport DNA and/or proteins through the membranes of bacteria. Analysis of T4S system architecture is an extremely challenging task taking into account their multi protein organisation and lack of overall global symmetry. Nonetheless the last decade demonstrated an amazing progress achieved by X-ray crystallography and cryo-electron microscopy. In this review we present a structural analysis of this dynamic complex based on recent advances in biochemical, biophysical and structural studies.

  15. Transmission electron microscopy investigation of Bi-2223/Ag tapes

    DEFF Research Database (Denmark)

    Andersen, L.G.; Bals, S.; Tendeloo, G. Van

    2001-01-01

    The microstructure of (Bi,Pb)(2)Sr2Ca2CuOx (Bi-2223) tapes has been investigated by means of transmission electron microscopy (TEM) and high-resolution TEM. The emphasis has been placed on: (1) an examination of the grain morphology and size, (2) grain and colony boundary angles, which are formed...... the first annealing. The angles of c-axis tilt grain boundaries are on average 14 degrees and 26 degrees for the fully processed tape and the tape after the first annealing, respectively. The intergrowth content(15%) and distribution are similar in these two tapes. (C) 2001 Elsevier Science B.V. All rights...

  16. Droplet Epitaxy Image Contrast in Mirror Electron Microscopy

    Science.gov (United States)

    Kennedy, S. M.; Zheng, C. X.; Jesson, D. E.

    2017-01-01

    Image simulation methods are applied to interpret mirror electron microscopy (MEM) images obtained from a movie of GaAs droplet epitaxy. Cylindrical symmetry of structures grown by droplet epitaxy is assumed in the simulations which reproduce the main features of the experimental MEM image contrast, demonstrating that droplet epitaxy can be studied in real-time. It is therefore confirmed that an inner ring forms at the droplet contact line and an outer ring (or skirt) occurs outside the droplet periphery. We believe that MEM combined with image simulations will be increasingly used to study the formation and growth of quantum structures.

  17. Assessment of the contribution of electron microscopy to nanoparticle characterization sampled with two cascade impactors.

    Science.gov (United States)

    Noël, Alexandra; L'Espérance, Gilles; Cloutier, Yves; Plamondon, Philippe; Boucher, Julie; Philippe, Suzanne; Dion, Chantal; Truchon, Ginette; Zayed, Joseph

    2013-01-01

    This study assessed the contribution of electron microscopy to the characterization of nanoparticles and compared the degree of variability in sizes observed within each stage when sampled by two cascade impactors: an Electrical Low Pressure Impactor (ELPI) and a Micro-Orifice Uniform Deposit Impactor (MOUDI). A TiO(2) nanoparticle (5 nm) suspension was aerosolized in an inhalation chamber. Nanoparticles sampled by the impactors were collected on aluminum substrates or TEM carbon-coated copper grids using templates, specifically designed in our laboratories, for scanning and transmission electron microscopy (SEM, TEM) analysis, respectively. Nanoparticles were characterized using both SEM and TEM. Three different types of diameters (inner, outer, and circular) were measured by image analysis based on count and volume, for each impactor stage. Electron microscopy, especially TEM, is well suited for the characterization of nanoparticles. The MOUDI, probably because of the rotation of its collection stages, which can minimize the resuspension of particles, gave more stable results and smaller geometric standard deviations per stage. Our data suggest that the best approach to estimate particle size by electron microscopy would rely on geometric means of measured circular diameters. Overall, the most reliable data were provided by the MOUDI and the TEM sampling technique on carbon-coated copper grids for this specific experiment. This study indicates interesting findings related to the assessment of impactors combined with electron microscopy for nanoparticle characterization. For future research, since cascade impactors are extensively used to characterize nano-aerosol exposure scenarios, high-performance field emission scanning electron microscopy (FESEM) should also be considered.

  18. Electron microscopy of primary cell cultures in solution and correlative optical microscopy using ASEM.

    Science.gov (United States)

    Hirano, Kazumi; Kinoshita, Takaaki; Uemura, Takeshi; Motohashi, Hozumi; Watanabe, Yohei; Ebihara, Tatsuhiko; Nishiyama, Hidetoshi; Sato, Mari; Suga, Mitsuo; Maruyama, Yuusuke; Tsuji, Noriko M; Yamamoto, Masayuki; Nishihara, Shoko; Sato, Chikara

    2014-08-01

    Correlative light-electron microscopy of cells in a natural environment of aqueous liquid facilitates high-throughput observation of protein complex formation. ASEM allows the inverted SEM to observe the wet sample from below, while an optical microscope observes it from above quasi-simultaneously. The disposable ASEM dish with a silicon nitride (SiN) film window can be coated variously to realize the primary-culture of substrate-sensitive cells in a few milliliters of culture medium in a stable incubator environment. Neuron differentiation, neural networking, proplatelet-formation and phagocytosis were captured by optical or fluorescence microscopy, and imaged at high resolution by gold-labeled immuno-ASEM with/without metal staining. Fas expression on the cell surface was visualized, correlated to the spatial distribution of F-actin. Axonal partitioning was studied using primary-culture neurons, and presynaptic induction by GluRδ2-N-terminus-linked fluorescent magnetic beads was correlated to the presynaptic-marker Bassoon. Further, megakaryocytes secreting proplatelets were captured, and P-selectins with adherence activity were localized to some of the granules present by immuno-ASEM. The phagocytosis of lactic acid bacteria by dendritic cells was also imaged. Based on these studies, ASEM correlative microscopy promises to allow the study of various mesoscopic-scale dynamics in the near future. © 2013 Published by Elsevier B.V.

  19. Transmission Electron Microscopy of a CMSX-4 Ni-Base Superalloy Produced by Selective Electron Beam Melting

    Directory of Open Access Journals (Sweden)

    Alireza B. Parsa

    2016-10-01

    Full Text Available In this work, the microstructures of superalloy specimens produced using selective electron beam melting additive manufacturing were characterized. The materials were produced using a CMSX-4 powder. Two selective electron beam melting processing strategies, which result in higher and lower effective cooling rates, are described. Orientation imaging microscopy, scanning transmission electron microscopy and conventional high resolution transmission electron microscopy are used to investigate the microstructures. Our results suggest that selective electron beam melting processing results in near equilibrium microstructures, as far as γ′ volume fractions, the formation of small amounts of TCP phases and the partitioning behavior of the alloy elements are concerned. As expected, higher cooling rates result in smaller dendrite spacings, which are two orders of magnitude smaller than observed during conventional single crystal casting. During processing, columnar grains grow in <100> directions, which are rotated with respect to each other. There are coarse γ/γ′ microstructures in high angle boundary regions. Dislocation networks form low angle boundaries. A striking feature of the as processed selective electron beam melting specimens is their high dislocation density. From a fundamental point of view, this opens new possibilities for the investigation of elementary dislocation processes which accompany solidification.

  20. Advanced electron microscopy characterization of nanomaterials for catalysis

    Directory of Open Access Journals (Sweden)

    Dong Su

    2017-04-01

    Full Text Available Transmission electron microscopy (TEM has become one of the most powerful techniques in the fields of material science, inorganic chemistry and nanotechnology. In terms of resolutions, advanced TEM may reach a high spatial resolution of 0.05 nm, a high energy-resolution of 7 meV. In addition, in situ TEM can help researchers to image the process happened within 1 ms. This paper reviews the recent technical progresses of applying advanced TEM characterization on nanomaterials for catalysis. The text is organized based on the perspective of application: for example, size, composition, phase, strain, and morphology. The electron beam induced effect and in situ TEM are also introduced. I hope this review can help the scientists in related fields to take advantage of advanced TEM to their own researches. Keywords: Advanced TEM, Nanomaterials, Catalysts, In situ

  1. Clean electromigrated nanogaps imaged by transmission electron microscopy.

    Science.gov (United States)

    Strachan, Douglas R; Smith, Deirdre E; Fischbein, Michael D; Johnston, Danvers E; Guiton, Beth S; Drndić, Marija; Bonnell, Dawn A; Johnson, Alan T

    2006-03-01

    Electromigrated nanogaps have shown great promise for use in molecular scale electronics. We have fabricated nanogaps on free-standing transparent SiN(x) membranes which permit the use of transmission electron microscopy (TEM) to image the gaps. The electrodes are formed by extending a recently developed controlled electromigration procedure and yield a nanogap with approximately 5 nm separation clear of any apparent debris. The gaps are stable, on the order of hours as measured by TEM, but over time (months) relax to about 20 nm separation determined by the surface energy of the Au electrodes. A major benefit of electromigrated nanogaps on SiN(x) membranes is that the junction pinches in away from residual metal left from the Au deposition which could act as a parasitic conductance path. This work has implications to the design of clean metallic electrodes for use in nanoscale devices where the precise geometry of the electrode is important.

  2. Cryo electron microscopy to determine the structure of macromolecular complexes.

    Science.gov (United States)

    Carroni, Marta; Saibil, Helen R

    2016-02-15

    Cryo-electron microscopy (cryo-EM) is a structural molecular and cellular biology technique that has experienced major advances in recent years. Technological developments in image recording as well as in processing software make it possible to obtain three-dimensional reconstructions of macromolecular assemblies at near-atomic resolution that were formerly obtained only by X-ray crystallography or NMR spectroscopy. In parallel, cryo-electron tomography has also benefitted from these technological advances, so that visualization of irregular complexes, organelles or whole cells with their molecular machines in situ has reached subnanometre resolution. Cryo-EM can therefore address a broad range of biological questions. The aim of this review is to provide a brief overview of the principles and current state of the cryo-EM field. Copyright © 2016. Published by Elsevier Inc.

  3. Transmission electron microscopy for thin film solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Reininghaus, Nies; Schmidt, Vitalij; Hachmann, Wiebke; Heinzmann, Ulrich [Molecular and Surface Physics, Bielefeld University (Germany); Gruss, Stefan; Stiebig, Helmut [Malibu GmbH and Co. KG, Bielefeld (Germany)

    2011-07-01

    Thin-film amorphous and microcrystalline silicon are promising materials for photovoltaics as they have the potential to reduce the solar cell costs. In case of microcrystalline silicon the crystalline volume fraction is related to the efficiency factor of solar cells because it provides information about the microstructure of the material and the defect density. With Transmission Electron Microscopy of cross-sections it is possible to show the microstructure of the cells. However to determine the structure of the bulk it is necessary to analyse the diffraction of the electron beam. For the purpose of imaging diffraction patterns and displaying dark fields a new camera system has been installed in the Phillips CM200. With much higher sensitivity and a larger photoactive area it is possible to take images of the low-intensity diffraction and the dark field patterns.

  4. Early studies of placental ultrastructure by electron microscopy

    DEFF Research Database (Denmark)

    Carter, A M; Enders, A C

    2016-01-01

    BACKGROUND: Transmission electron microscopy (TEM) was first applied to study placental ultrastructure in the 1950's. We review those early studies and mention the scientists that employed or encouraged the use of TEM. FINDINGS: Among the pioneers Edward W. Dempsey was a key figure who attracted...... many other scientists to Washington University in St. Louis. Work on human placental ultrastructure was initiated at Cambridge and Kyoto whilst domestic animals were initially studied by Björkman in Stockholm and electron micrographs of bat placenta were published by Wimsatt of Cornell University....... CONCLUSIONS: Prior to the introduction of better fixation techniques, TEM images were of modest technical quality. Nevertheless they gave important insights into placental ultrastructure, particularly the nature of the maternal-fetal interface....

  5. Visualizing aquatic bacteria by light and transmission electron microscopy.

    Science.gov (United States)

    Silva, Thiago P; Noyma, Natália P; Duque, Thabata L A; Gamalier, Juliana P; Vidal, Luciana O; Lobão, Lúcia M; Chiarini-Garcia, Hélio; Roland, Fábio; Melo, Rossana C N

    2014-01-01

    The understanding of the functional role of aquatic bacteria in microbial food webs is largely dependent on methods applied to the direct visualization and enumeration of these organisms. While the ultrastructure of aquatic bacteria is still poorly known, routine observation of aquatic bacteria by light microscopy requires staining with fluorochromes, followed by filtration and direct counting on filter surfaces. Here, we used a new strategy to visualize and enumerate aquatic bacteria by light microscopy. By spinning water samples from varied tropical ecosystems in a cytocentrifuge, we found that bacteria firmly adhere to regular slides, can be stained by fluorochoromes with no background formation and fast enumerated. Significant correlations were found between the cytocentrifugation and filter-based methods. Moreover, preparations through cytocentrifugation were more adequate for bacterial viability evaluation than filter-based preparations. Transmission electron microscopic analyses revealed a morphological diversity of bacteria with different internal and external structures, such as large variation in the cell envelope and capsule thickness, and presence or not of thylakoid membranes. Our results demonstrate that aquatic bacteria represent an ultrastructurally diverse population and open avenues for easy handling/quantification and better visualization of bacteria by light microscopy without the need of filter membranes.

  6. Electron beam confinement and image contrast enhancement in near field emission scanning electron microscopy.

    Science.gov (United States)

    Kirk, T L; De Pietro, L G; Pescia, D; Ramsperger, U

    2009-04-01

    In conventional scanning electron microscopy (SEM), the lateral resolution is limited by the electron beam diameter impinging on the specimen surface. Near field emission scanning electron microscopy (NFESEM) provides a simple means of overcoming this limit; however, the most suitable field emitter remains to be determined. NFESEM has been used in this work to investigate the W (110) surface with single-crystal tungsten tips of (310), (111), and (100)-orientations. The topographic images generated from both the electron intensity variations and the field emission current indicate higher resolution capabilities with decreasing tip work function than with polycrystalline tungsten tips. The confinement of the electron beam transcends the resolution limitations of the geometrical models, which are determined by the minimum beam width.

  7. New modes of electron microscopy for materials science enabled by fast direct electron detectors

    Science.gov (United States)

    Minor, Andrew

    There is an ongoing revolution in the development of electron detector technology that has enabled modes of electron microscopy imaging that had only before been theorized. The age of electron microscopy as a tool for imaging is quickly giving way to a new frontier of multidimensional datasets to be mined. These improvements in electron detection have enabled cryo-electron microscopy to resolve the three-dimensional structures of non-crystalized proteins, revolutionizing structural biology. In the physical sciences direct electron detectors has enabled four-dimensional reciprocal space maps of materials at atomic resolution, providing all the structural information about nanoscale materials in one experiment. This talk will highlight the impact of direct electron detectors for materials science, including a new method of scanning nanobeam diffraction. With faster detectors we can take a series of 2D diffraction patterns at each position in a 2D STEM raster scan resulting in a four-dimensional data set. For thin film analysis, direct electron detectors hold the potential to enable strain, polarization, composition and electrical field mapping over relatively large fields of view, all from a single experiment.

  8. Hybrid fluorescence and electron cryo-microscopy for simultaneous electron and photon imaging.

    Science.gov (United States)

    Iijima, Hirofumi; Fukuda, Yoshiyuki; Arai, Yoshihiro; Terakawa, Susumu; Yamamoto, Naoki; Nagayama, Kuniaki

    2014-01-01

    Integration of fluorescence light and transmission electron microscopy into the same device would represent an important advance in correlative microscopy, which traditionally involves two separate microscopes for imaging. To achieve such integration, the primary technical challenge that must be solved regards how to arrange two objective lenses used for light and electron microscopy in such a manner that they can properly focus on a single specimen. To address this issue, both lateral displacement of the specimen between two lenses and specimen rotation have been proposed. Such movement of the specimen allows sequential collection of two kinds of microscopic images of a single target, but prevents simultaneous imaging. This shortcoming has been made up by using a simple optical device, a reflection mirror. Here, we present an approach toward the versatile integration of fluorescence and electron microscopy for simultaneous imaging. The potential of simultaneous hybrid microscopy was demonstrated by fluorescence and electron sequential imaging of a fluorescent protein expressed in cells and cathodoluminescence imaging of fluorescent beads. Copyright © 2013 Elsevier Inc. All rights reserved.

  9. Annular dark field transmission electron microscopy for protein structure determination

    Energy Technology Data Exchange (ETDEWEB)

    Koeck, Philip J.B., E-mail: Philip.Koeck@ki.se

    2016-02-15

    Recently annular dark field (ADF) transmission electron microscopy (TEM) has been advocated as a means of recording images of biological specimens with better signal to noise ratio (SNR) than regular bright field images. I investigate whether and how such images could be used to determine the three-dimensional structure of proteins given that an ADF aperture with a suitable pass-band can be manufactured and used in practice. I develop an approximate theory of ADF-TEM image formation for weak amplitude and phase objects and test this theory using computer simulations. I also test whether these simulated images can be used to calculate a three-dimensional model of the protein using standard software and discuss problems and possible ways to overcome these. - Highlights: • I present theory and simulations for imaging proteins using annular dark field transmission electron microscopy and investigate its suitability for 3D-reconstruction. • I show that the images are approximately proportional to the square of the projected electrostatic potential within a given passband ). • 3D-reconstructions show errors in the interior of the molecule. More accurate maps might be calculated by reconstruction algorithms that take into account non-linear image formation.

  10. Collaborative Computational Project for Electron cryo-Microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Wood, Chris; Burnley, Tom [Science and Technology Facilities Council, Research Complex at Harwell, Didcot OX11 0FA (United Kingdom); Patwardhan, Ardan [European Molecular Biology Laboratory, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SD (United Kingdom); Scheres, Sjors [MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH (United Kingdom); Topf, Maya [University of London, Malet Street, London WC1E 7HX (United Kingdom); Roseman, Alan [University of Manchester, Oxford Road, Manchester M13 9PT (United Kingdom); Winn, Martyn, E-mail: martyn.winn@stfc.ac.uk [Science and Technology Facilities Council, Daresbury Laboratory, Warrington WA4 4AD (United Kingdom); Science and Technology Facilities Council, Research Complex at Harwell, Didcot OX11 0FA (United Kingdom)

    2015-01-01

    The Collaborative Computational Project for Electron cryo-Microscopy (CCP-EM) is a new initiative for the structural biology community, following the success of CCP4 for macromolecular crystallography. Progress in supporting the users and developers of cryoEM software is reported. The Collaborative Computational Project for Electron cryo-Microscopy (CCP-EM) has recently been established. The aims of the project are threefold: to build a coherent cryoEM community which will provide support for individual scientists and will act as a focal point for liaising with other communities, to support practising scientists in their use of cryoEM software and finally to support software developers in producing and disseminating robust and user-friendly programs. The project is closely modelled on CCP4 for macromolecular crystallography, and areas of common interest such as model fitting, underlying software libraries and tools for building program packages are being exploited. Nevertheless, cryoEM includes a number of techniques covering a large range of resolutions and a distinct project is required. In this article, progress so far is reported and future plans are discussed.

  11. Investigation of porous asphalt microstructure using optical and electron microscopy.

    Science.gov (United States)

    Poulikakos, L D; Partl, M N

    2010-11-01

    Direct observations of porous asphalt concrete samples in their natural state using optical and electron microscopy techniques led to useful information regarding the microstructure of two mixes and indicated a relationship between microstructure and in situ performance. This paper presents evidence that suboptimal microstructure can lead to premature failure thus making a first step in defining well or suboptimal performing pavements with a bottom-up approach (microstructure). Laboratory and field compaction produce different samples in terms of the microstructure. Laboratory compaction using the gyratory method has produced more microcracks in mineral aggregates after the binder had cooled. Well-performing mixes used polymer-modified binders, had a more homogeneous void structure with fewer elongated voids and better interlocking of the aggregates. Furthermore, well-performing mixes showed better distribution of the mastic and better coverage of the aggregates with bitumen. Low vacuum scanning electron microscopy showed that styrene butadiene styrene polymer modification in binder exists in the form of discontinuous globules and not continuous networks. A reduction in the polymer phase was observed as a result of aging and in-service use. © 2010 The Authors Journal compilation © 2010 The Royal Microscopical Society.

  12. A Technique for In Situ Ballistic Electron Emission Microscopy

    Science.gov (United States)

    Balsano, Robert; Garramone, John; Labella, Vincent

    2012-02-01

    Ballistic electron emission microscopy (BEEM) is a scanning tunneling microscopy (STM) technique that can measure transport of hot electrons through materials and interfaces with high spatial and energetic resolution. BEEM requires an additional contact to ground the metal base layer of a metal semiconductor junction. Performing BEEM in situ with the sample fabrication requires a custom built STM or modifying a commercial one to facilitate the extra contact, which leaves the technique to highly trained experts. This poster will describe our work to develop a special silicon substrate that has the extra contact built in to enable in situ BEEM without modifications to the STM. Electrically isolated contact traces are lithographically patterned ex situ onto the silicon substrate and connected to the BEEM sample plate which is then inserted into the ultra-high vacuum chamber. The metal is then deposited through a shadow mask and then mounted in situ onto the STM for BEEM measurements. BEEM measurements comparing both in situ and ex situ deposited films will be presented.

  13. Golgi apparatus analyzed by cryo-electron microscopy.

    Science.gov (United States)

    Han, Hong-Mei; Bouchet-Marquis, Cedric; Huebinger, Jan; Grabenbauer, Markus

    2013-10-01

    In 1898, the Golgi apparatus was discovered by light microscopy, and since the 1950s, the ultrastructure composition is known by electron microscopic investigation. The complex three-dimensional morphology fascinated researchers and was sometimes even the driving force to develop novel visualization techniques. However, the highly dynamic membrane systems of Golgi apparatus are delicate and prone to fixation artifacts. Therefore, the understanding of Golgi morphology and its function has been improved significantly with the development of better preparation methods. Nowadays, cryo-fixation is the method of choice to arrest instantly all dynamic and physiological processes inside cells, tissues, and small organisms. Embedded in amorphous ice, such samples can be further processed by freeze substitution or directly analyzed in their fully hydrated state by cryo-electron microscopy and tomography. Even though the overall morphology of vitrified Golgi stacks is comparable to well-prepared and resin-embedded samples, previously unknown structural details can be observed solely based on their native density. At this point, any further improvement of sample preparation would gain novel insights, perhaps not in terms of general morphology, but on fine structural details of this dynamic organelle.

  14. Spiral phase plate contrast in optical and electron microscopy

    Science.gov (United States)

    Juchtmans, Roeland; Clark, Laura; Lubk, Axel; Verbeeck, Jo

    2016-08-01

    The use of phase plates in the back focal plane of a microscope is a well-established technique in optical microscopy to increase the contrast of weakly interacting samples and is gaining interest in electron microscopy as well. In this paper we study the spiral phase plate (SPP), also called helical, vortex, or two-dimensional Hilbert phase plate, which adds an angularly dependent phase of the form ei ℓ ϕk to the exit wave in Fourier space. In the limit of large collection angles, we analytically calculate that the average of a pair of ℓ =±1 SPP filtered images is directly proportional to the gradient squared of the exit wave, explaining the edge contrast previously seen in optical SPP work. We discuss the difference between a clockwise-anticlockwise pair of SPP filtered images and derive conditions under which the modulus of the wave's gradient can be seen directly from one SPP filtered image. This work provides the theoretical background to interpret images obtained with a SPP, thereby opening new perspectives for new experiments to study, for example, magnetic materials in an electron microscope.

  15. Amyloid Structure and Assembly: Insights from Scanning Transmission Electron Microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Goldsbury, C.; Wall, J.; Baxa, U.; Simon, M. N.; Steven, A. C.; Engel, A.; Aebi, U.; Muller, S. A.

    2011-01-01

    Amyloid fibrils are filamentous protein aggregates implicated in several common diseases such as Alzheimer's disease and type II diabetes. Similar structures are also the molecular principle of the infectious spongiform encephalopathies such as Creutzfeldt-Jakob disease in humans, scrapie in sheep, and of the so-called yeast prions, inherited non-chromosomal elements found in yeast and fungi. Scanning transmission electron microscopy (STEM) is often used to delineate the assembly mechanism and structural properties of amyloid aggregates. In this review we consider specifically contributions and limitations of STEM for the investigation of amyloid assembly pathways, fibril polymorphisms and structural models of amyloid fibrils. This type of microscopy provides the only method to directly measure the mass-per-length (MPL) of individual filaments. Made on both in vitro assembled and ex vivo samples, STEM mass measurements have illuminated the hierarchical relationships between amyloid fibrils and revealed that polymorphic fibrils and various globular oligomers can assemble simultaneously from a single polypeptide. The MPLs also impose strong constraints on possible packing schemes, assisting in molecular model building when combined with high-resolution methods like solid-state nuclear magnetic resonance (NMR) and electron paramagnetic resonance (EPR).

  16. Transmission electron microscopy a textbook for materials science

    CERN Document Server

    Williams, David B

    1996-01-01

    Electron microscopy has revolutionized our understanding the extraordinary intellectual demands required of the mi­ of materials by completing the processing-structure-prop­ croscopist in order to do the job properly: crystallography, erties links down to atomistic levels. It now is even possible diffraction, image contrast, inelastic scattering events, and to tailor the microstructure (and meso structure ) of materials spectroscopy. Remember, these used to be fields in them­ to achieve specific sets of properties; the extraordinary abili­ selves. Today, one has to understand the fundamentals ties of modem transmission electron microscopy-TEM­ of all of these areas before one can hope to tackle signifi­ instruments to provide almost all of the structural, phase, cant problems in materials science. TEM is a technique of and crystallographic data allow us to accomplish this feat. characterizing materials down to the atomic limits. It must Therefore, it is obvious that any curriculum in modem mate­ be use...

  17. A national facility for biological cryo-electron microscopy.

    Science.gov (United States)

    Saibil, Helen R; Grünewald, Kay; Stuart, David I

    2015-01-01

    Three-dimensional electron microscopy is an enormously powerful tool for structural biologists. It is now able to provide an understanding of the molecular machinery of cells, disease processes and the actions of pathogenic organisms from atomic detail through to the cellular context. However, cutting-edge research in this field requires very substantial resources for equipment, infrastructure and expertise. Here, a brief overview is provided of the plans for a UK national three-dimensional electron-microscopy facility for integrated structural biology to enable internationally leading research on the machinery of life. State-of-the-art equipment operated with expert support will be provided, optimized for both atomic-level single-particle analysis of purified macromolecules and complexes and for tomography of cell sections. The access to and organization of the facility will be modelled on the highly successful macromolecular crystallography (MX) synchrotron beamlines, and will be embedded at the Diamond Light Source, facilitating the development of user-friendly workflows providing near-real-time experimental feedback.

  18. Characterization of strained semiconductor structures using transmission electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Oezdoel, Vasfi Burak

    2011-08-15

    Today's state-of-the-art semiconductor electronic devices utilize the charge transport within very small volumes of the active device regions. The structural, chemical and optical material properties in these small dimensions can critically affect the performance of these devices. The present thesis is focused on the nanometer scale characterization of the strain state in semiconductor structures using transmission electron microscopy (TEM). Although high-resolution TEM has shown to provide the required accuracy at the nanometer scale, optimization of imaging conditions is necessary for accurate strain measurements. An alternative HRTEM method based on strain mapping on complex-valued exit face wave functions is developed to reduce the artifacts arising from objective lens aberrations. However, a much larger field of view is crucial for mapping strain in the active regions of complex structures like latest generation metal-oxide-semiconductor field-effect transistors (MOSFETs). To overcome this, a complementary approach based on electron holography is proposed. The technique relies on the reconstruction of the phase shifts in the diffracted electron beams from a focal series of dark-field images using recently developed exit-face wave function reconstruction algorithm. Combining high spatial resolution, better than 1 nm, with a field of view of about 1 {mu}m in each dimension, simultaneous strain measurements on the array of MOSFETs are possible. Owing to the much lower electron doses used in holography experiments when compared to conventional quantitative methods, the proposed approach allows to map compositional distribution in electron beam sensitive materials such as InGaN heterostructures without alteration of the original morphology and chemical composition. Moreover, dark-field holography experiments can be performed on thicker specimens than the ones required for high-resolution TEM, which in turn reduces the thin foil relaxation. (orig.)

  19. Bright-field scanning confocal electron microscopy using a double aberration-corrected transmission electron microscope

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Peng; Behan, Gavin; Kirkland, Angus I. [Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH (United Kingdom); Nellist, Peter D., E-mail: peter.nellist@materials.ox.ac.uk [Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH (United Kingdom); Cosgriff, Eireann C.; D' Alfonso, Adrian J.; Morgan, Andrew J.; Allen, Leslie J. [School of Physics, University of Melbourne, Parkville, Victoria 3010 (Australia); Hashimoto, Ayako [Advanced Nano-characterization Center, National Institute for Materials Science (NIMS), 3-13 Sakura, Tsukuba 305-0003 (Japan); Takeguchi, Masaki [Advanced Nano-characterization Center, National Institute for Materials Science (NIMS), 3-13 Sakura, Tsukuba 305-0003 (Japan); High Voltage Electron Microscopy Station, NIMS, 3-13 Sakura, Tsukuba 305-0003 (Japan); Mitsuishi, Kazutaka [Advanced Nano-characterization Center, National Institute for Materials Science (NIMS), 3-13 Sakura, Tsukuba 305-0003 (Japan); Quantum Dot Research Center, NIMS, 3-13 Sakura, Tsukuba 305-0003 (Japan); Shimojo, Masayuki [High Voltage Electron Microscopy Station, NIMS, 3-13 Sakura, Tsukuba 305-0003 (Japan); Advanced Science Research Laboratory, Saitama Institute of Technology, 1690 Fusaiji, Fukaya 369-0293 (Japan)

    2011-06-15

    Scanning confocal electron microscopy (SCEM) offers a mechanism for three-dimensional imaging of materials, which makes use of the reduced depth of field in an aberration-corrected transmission electron microscope. The simplest configuration of SCEM is the bright-field mode. In this paper we present experimental data and simulations showing the form of bright-field SCEM images. We show that the depth dependence of the three-dimensional image can be explained in terms of two-dimensional images formed in the detector plane. For a crystalline sample, this so-called probe image is shown to be similar to a conventional diffraction pattern. Experimental results and simulations show how the diffracted probes in this image are elongated in thicker crystals and the use of this elongation to estimate sample thickness is explored. -- Research Highlights: {yields} The confocal probe image in a scanning confocal electron microscopy image reveals information about the thickness and height of the crystalline layer. {yields} The form of the contrast in a three-dimensional bright-field scanning confocal electron microscopy image can be explained in terms of the confocal probe image. {yields} Despite the complicated form of the contrast in bright-field scanning confocal electron microscopy, we see that depth information is transferred on a 10 nm scale.

  20. Low-cost cryo-light microscopy stage fabrication for correlated light/electron microscopy.

    Science.gov (United States)

    Carlson, David B; Evans, James E

    2011-06-05

    The coupling of cryo-light microscopy (cryo-LM) and cryo-electron microscopy (cryo-EM) poses a number of advantages for understanding cellular dynamics and ultrastructure. First, cells can be imaged in a near native environment for both techniques. Second, due to the vitrification process, samples are preserved by rapid physical immobilization rather than slow chemical fixation. Third, imaging the same sample with both cryo-LM and cryo-EM provides correlation of data from a single cell, rather than a comparison of "representative samples". While these benefits are well known from prior studies, the widespread use of correlative cryo-LM and cryo-EM remains limited due to the expense and complexity of buying or building a suitable cryogenic light microscopy stage. Here we demonstrate the assembly, and use of an inexpensive cryogenic stage that can be fabricated in any lab for less than $40 with parts found at local hardware and grocery stores. This cryo-LM stage is designed for use with reflected light microscopes that are fitted with long working distance air objectives. For correlative cryo-LM and cryo-EM studies, we adapt the use of carbon coated standard 3-mm cryo-EM grids as specimen supports. After adsorbing the sample to the grid, previously established protocols for vitrifying the sample and transferring/handling the grid are followed to permit multi-technique imaging. As a result, this setup allows any laboratory with a reflected light microscope to have access to direct correlative imaging of frozen hydrated samples.

  1. High-precision correlative fluorescence and electron cryo microscopy using two independent alignment markers ☆

    OpenAIRE

    Schellenberger, Pascale; Kaufmann, Rainer; Siebert, C. Alistair; Hagen, Christoph; Wodrich, Harald; Grünewald, Kay

    2014-01-01

    Correlative light and electron microscopy (CLEM) is an emerging technique which combines functional information provided by fluorescence microscopy (FM) with the high-resolution structural information of electron microscopy (EM). So far, correlative cryo microscopy of frozen-hydrated samples has not reached better than micrometre range accuracy. Here, a method is presented that enables the correlation between fluorescently tagged proteins and electron cryo tomography (cryoET) data with nanome...

  2. Cryo-electron microscopy of extracellular vesicles in fresh plasma.

    Science.gov (United States)

    Yuana, Yuana; Koning, Roman I; Kuil, Maxim E; Rensen, Patrick C N; Koster, Abraham J; Bertina, Rogier M; Osanto, Susanne

    2013-12-31

    Extracellular vesicles (EV) are phospholipid bilayer-enclosed vesicles recognized as new mediators in intercellular communication and potential biomarkers of disease. They are found in many body fluids and mainly studied in fractions isolated from blood plasma in view of their potential in medicine. Due to the limitations of available analytical methods, morphological information on EV in fresh plasma is still rather limited. To image EV and determine the morphology, structure and size distribution in fresh plasma by cryo-electron microscopy (cryo-EM). Fresh citrate- and ethylenediaminetetraacetic acid (EDTA)-anticoagulated plasma or EV isolated from these plasmas were rapidly cryo-immobilized by vitrification and visualized by cryo-EM. EV isolated from fresh plasma were highly heterogeneous in morphology and size and mostly contain a discernible lipid bilayer (lipid vesicles). In fresh plasma there were 2 types of particles with a median diameter of 30 nm (25-260 nm). The majority of these particles are electron dense particles which most likely represent lipoproteins. The minority are lipid vesicles, either electron dense or electron lucent, which most likely represent EV. Lipid vesicles were occasionally observed in close proximity of platelets in citrate and EDTA-anticoagulated platelet-rich plasma. Cryo-electron tomography (cryo-ET) was employed to determine the 3D structure of platelet secretory granules. Cryo-EM is a powerful technique that enables the characterization of EV in fresh plasma revealing structural details and considerable morphological heterogeneity. Only a small proportion of the submicron structures in fresh plasma are lipid vesicles representing EV.

  3. Cryo-electron microscopy of extracellular vesicles in fresh plasma

    Directory of Open Access Journals (Sweden)

    Yuana Yuana

    2013-12-01

    Full Text Available Introduction: Extracellular vesicles (EV are phospholipid bilayer-enclosed vesicles recognized as new mediators in intercellular communication and potential biomarkers of disease. They are found in many body fluids and mainly studied in fractions isolated from blood plasma in view of their potential in medicine. Due to the limitations of available analytical methods, morphological information on EV in fresh plasma is still rather limited. Objectives: To image EV and determine the morphology, structure and size distribution in fresh plasma by cryo-electron microscopy (cryo-EM. Methods: Fresh citrate- and ethylenediaminetetraacetic acid (EDTA-anticoagulated plasma or EV isolated from these plasmas were rapidly cryo-immobilized by vitrification and visualized by cryo-EM. Results: EV isolated from fresh plasma were highly heterogeneous in morphology and size and mostly contain a discernible lipid bilayer (lipid vesicles. In fresh plasma there were 2 types of particles with a median diameter of 30 nm (25–260 nm. The majority of these particles are electron dense particles which most likely represent lipoproteins. The minority are lipid vesicles, either electron dense or electron lucent, which most likely represent EV. Lipid vesicles were occasionally observed in close proximity of platelets in citrate and EDTA-anticoagulated platelet-rich plasma. Cryo-electron tomography (cryo-ET was employed to determine the 3D structure of platelet secretory granules. Conclusions: Cryo-EM is a powerful technique that enables the characterization of EV in fresh plasma revealing structural details and considerable morphological heterogeneity. Only a small proportion of the submicron structures in fresh plasma are lipid vesicles representing EV.

  4. Preliminary Study of In Vivo Formed Dental Plaque Using Confocal Microscopy and Scanning Electron Microscopy

    Directory of Open Access Journals (Sweden)

    KA. Al-Salihi

    2009-12-01

    Full Text Available Objective: Confocal laser scanning microscopy (CLSM is relatively a new light microscopical imaging technique with a wide range of applications in biological sciences. The primary value of CLSM for the biologist is its ability to provide optical sections from athree-dimensional specimen. The present study was designed to assess the thickness and content of in vivo accumulated dental plaque using CLSM and scanning electron microscopy (SEM.Materials and Methods: Acroflat lower arch splints (acrylic appliance were worn by five participants for three days without any disturbance. The formed plaques were assessed using CLSM combined with vital fluorescence technique and SEM.Results: In this study accumulated dental plaque revealed varied plaque microflora vitality and thickness according to participant’s oral hygiene. The thickness of plaque smears ranged from 40.32 to 140.72 μm and 65.00 to 128.88 μm for live (vital and dead accumulated microorganisms, respectively. Meanwhile, the thickness of plaque on the appliance ranged from 101 μm to 653 μm. CLSM revealed both dead and vital bacteria on the surface of the dental plaque. In addition, SEM revealed layers of various bacterial aggregations in all dental plaques.Conclusion: This study offers a potent non-invasive tool to evaluate and assess the dental plaque biofilm, which is a very important factor in the development of dental caries.

  5. Thermal Balloon Endometrial Ablation: Safety Aspects Evaluated by Serosal Temperature, Light Microscopy and Electron Microscopy

    DEFF Research Database (Denmark)

    Andersen, L F; Meinert, L; Rygaard, Carsten

    1998-01-01

    OBJECTIVES: Thermal balloon endometrial ablation is a new method for treating menorrhagia. The technique appears to be less difficult compared to standard hysteroscopic ablation techniques and to be significantly safer. The influence into the uterine wall of the thermal balloon ablation procedure...... was investigated with special reference to the ability of total destruction of the endometrium and the thermal action on the myometrium and the serosa. STUDY DESIGN: Temperatures were measured at the uterine serosal surface during thermal balloon endometrial ablation for 8-16 min in eight patients. After...... in all patients, with a maximum depth of 11.5 mm. By electron microscopy no influence of heat could be demonstrated beyond 15 mm from the endometrial surface. CONCLUSION: Up to 16 min of thermal balloon endometrial ablation therapy can destroy the endometrium and the submucosal layers. The myometrium...

  6. Thermal balloon endometrial ablation: safety aspects evaluated by serosal temperature, light microscopy and electron microscopy

    DEFF Research Database (Denmark)

    Andersen, L F; Meinert, L; Rygaard, Carsten

    1998-01-01

    OBJECTIVES: Thermal balloon endometrial ablation is a new method for treating menorrhagia. The technique appears to be less difficult compared to standard hysteroscopic ablation techniques and to be significantly safer. The influence into the uterine wall of the thermal balloon ablation procedure...... was investigated with special reference to the ability of total destruction of the endometrium and the thermal action on the myometrium and the serosa. STUDY DESIGN: Temperatures were measured at the uterine serosal surface during thermal balloon endometrial ablation for 8-16 min in eight patients. After...... in all patients, with a maximum depth of 11.5 mm. By electron microscopy no influence of heat could be demonstrated beyond 15 mm from the endometrial surface. CONCLUSION: Up to 16 min of thermal balloon endometrial ablation therapy can destroy the endometrium and the submucosal layers. The myometrium...

  7. Trends in the Electron Microscopy Data Bank (EMDB).

    Science.gov (United States)

    Patwardhan, Ardan

    2017-06-01

    Recent technological advances, such as the introduction of the direct electron detector, have transformed the field of cryo-EM and the landscape of molecular and cellular structural biology. This study analyses these trends from the vantage point of the Electron Microscopy Data Bank (EMDB), the public archive for three-dimensional EM reconstructions. Over 1000 entries were released in 2016, representing almost a quarter of the total number of entries (4431). Structures at better than 6 Å resolution now represent one of the fastest-growing categories, while the share of annually released tomography-related structures is approaching 20%. The use of direct electron detectors is growing very rapidly: they were used for 70% of the structures released in 2016, in contrast to none before 2011. Microscopes from FEI have an overwhelming lead in terms of usage, and the use of the RELION software package continues to grow rapidly after having attained a leading position in the field. China is rapidly emerging as a major player in the field, supplementing the US, Germany and the UK as the big four. Similarly, Tsinghua University ranks only second to the MRC Laboratory for Molecular Biology in terms of involvement in publications associated with cryo-EM structures at better than 4 Å resolution. Overall, the numbers point to a rapid democratization of the field, with more countries and institutes becoming involved.

  8. Transmission electron microscopy in molecular structural biology: A historical survey.

    Science.gov (United States)

    Harris, J Robin

    2015-09-01

    In this personal, historic account of macromolecular transmission electron microscopy (TEM), published data from the 1940s through to recent times is surveyed, within the context of the remarkable progress that has been achieved during this time period. The evolution of present day molecular structural biology is described in relation to the associated biological disciplines. The contribution of numerous electron microscope pioneers to the development of the subject is discussed. The principal techniques for TEM specimen preparation, thin sectioning, metal shadowing, negative staining and plunge-freezing (vitrification) of thin aqueous samples are described, with a selection of published images to emphasise the virtues of each method. The development of digital image analysis and 3D reconstruction is described in detail as applied to electron crystallography and reconstructions from helical structures, 2D membrane crystals as well as single particle 3D reconstruction of icosahedral viruses and macromolecules. The on-going development of new software, algorithms and approaches is highlighted before specific examples of the historical progress of the structural biology of proteins and viruses are presented. Copyright © 2014 Elsevier Inc. All rights reserved.

  9. Improved Zernike-type phase contrast for transmission electron microscopy.

    Science.gov (United States)

    Koeck, P J B

    2015-07-01

    Zernike phase contrast has been recognized as a means of recording high-resolution images with high contrast using a transmission electron microscope. This imaging mode can be used to image typical phase objects such as unstained biological molecules or cryosections of biological tissue. According to the original proposal discussed in Danev and Nagayama (2001) and references therein, the Zernike phase plate applies a phase shift of π/2 to all scattered electron beams outside a given scattering angle and an image is recorded at Gaussian focus or slight underfocus (below Scherzer defocus). Alternatively, a phase shift of -π/2 is applied to the central beam using the Boersch phase plate. The resulting image will have an almost perfect contrast transfer function (close to 1) from a given lowest spatial frequency up to a maximum resolution determined by the wave length, the amount of defocus and the spherical aberration of the microscope. In this paper, I present theory and simulations showing that this maximum spatial frequency can be increased considerably without loss of contrast by using a Zernike or Boersch phase plate that leads to a phase shift between scattered and unscattered electrons of only π /4, and recording images at Scherzer defocus. The maximum resolution can be improved even more by imaging at extended Scherzer defocus, though at the cost of contrast loss at lower spatial frequencies. © 2015 The Authors Journal of Microscopy © 2015 Royal Microscopical Society.

  10. Trends in the Electron Microscopy Data Bank (EMDB)

    Science.gov (United States)

    Patwardhan, Ardan

    2017-01-01

    Recent technological advances, such as the introduction of the direct electron detector, have transformed the field of cryo-EM and the landscape of molecular and cellular structural biology. This study analyses these trends from the vantage point of the Electron Microscopy Data Bank (EMDB), the public archive for three-dimensional EM reconstructions. Over 1000 entries were released in 2016, representing almost a quarter of the total number of entries (4431). Structures at better than 6 Å resolution now represent one of the fastest-growing categories, while the share of annually released tomography-related structures is approaching 20%. The use of direct electron detectors is growing very rapidly: they were used for 70% of the structures released in 2016, in contrast to none before 2011. Microscopes from FEI have an overwhelming lead in terms of usage, and the use of the RELION software package continues to grow rapidly after having attained a leading position in the field. China is rapidly emerging as a major player in the field, supplementing the US, Germany and the UK as the big four. Similarly, Tsinghua University ranks only second to the MRC Laboratory for Molecular Biology in terms of involvement in publications associated with cryo-EM structures at better than 4 Å resolution. Overall, the numbers point to a rapid democratization of the field, with more countries and institutes becoming involved. PMID:28580912

  11. Ultrasoft magnetic films investigated with Lorentz transmission electron microscopy and electron holography

    NARCIS (Netherlands)

    de Hosson, J.T.M.; Chechenin, N.G.; Alsem, D.H.; Vystavel, T.; Kooi, B.J.; Chezan, A.R; Boerma, D.O

    2002-01-01

    As a tribute to the scientific work of Professor Gareth Thomas in the field of structure-property relationships this paper delineates a new possibility of Lorentz transmission electron microscopy (LTEM) to study the magnetic properties of soft magnetic films. We show that in contrast to the

  12. Scanning electron microscopy of the neuropathology of murine cerebral malaria

    Directory of Open Access Journals (Sweden)

    Brenneis Christian

    2006-11-01

    Full Text Available Abstract Background The mechanisms leading to death and functional impairments due to cerebral malaria (CM are yet not fully understood. Most of the knowledge about the pathomechanisms of CM originates from studies in animal models. Though extensive histopathological studies of the murine brain during CM are existing, alterations have not been visualized by scanning electron microscopy (SEM so far. The present study investigates the neuropathological features of murine CM by applying SEM. Methods C57BL/6J mice were infected with Plasmodium berghei ANKA blood stages. When typical symptoms of CM developed perfused brains were processed for SEM or light microscopy, respectively. Results Ultrastructural hallmarks were disruption of vessel walls, parenchymal haemorrhage, leukocyte sequestration to the endothelium, and diapedesis of macrophages and lymphocytes into the Virchow-Robin space. Villous appearance of observed lymphocytes were indicative of activated state. Cerebral oedema was evidenced by enlargement of perivascular spaces. Conclusion The results of the present study corroborate the current understanding of CM pathophysiology, further support the prominent role of the local immune system in the neuropathology of CM and might expose new perspectives for further interventional studies.

  13. Photoemission Electron Microscopy as a Tool for Studying Steel Grains

    Science.gov (United States)

    Roese, Peter; Keutner, Christoph; Berges, Ulf; Espeter, Philipp; Westphal, Carsten

    2017-03-01

    Key properties of steel like stability, weldability, or ability for absorbing deformation energy are defined by their grain structure. The knowledge about their micrometer and submicrometer structure is of particular interest for tailor-cut macroscopic steel properties. We report on photoemission electron microscopy studies which in principle yield a higher magnification than comparable optical techniques. A flat surface without any topographic features was obtained by applying a non-etching preparation procedure. PEEM images showed very tiny phase islands embedded within a steel phase matrix. Furthermore, we developed an analysis procedure for PEEM images for dual-phase steels. As a result, it is possible to identify the individual work functions of different steel phases at the surface.

  14. High-Resolution Transmission Electron Microscopy - and Associated Techniques

    Science.gov (United States)

    Buseck, Peter; Cowley, John; Eyring, Leroy

    1989-02-01

    This book provides an introduction to the fundamental concepts, techniques, and methods used for electron microscopy at high resolution in space, energy, and even in time. It delineates the theory of elastic scattering, which is most useful for spectroscopic and chemical analyses. There are also discussions of the theory and practice of image calculations, and applications of HRTEM to the study of solid surfaces, highly disordered materials, solid state chemistry, mineralogy, semiconductors and metals. Contributors include J. Cowley, J. Spence, P. Buseck, P. Self, and M.A. O'Keefe. Compiled by experts in the fields of geology, physics and chemistry, this comprehensive text will be the standard reference for years to come.

  15. Immunolabeling for scanning electron microscopy (SEM) and field emission SEM.

    Science.gov (United States)

    Goldberg, Martin W

    2008-01-01

    Scanning electron microscopy (SEM) is a high resolution surface imaging technique. Many biological process and structures occur at surfaces and if antibodies are available, their components can be located within the surface structure. This is usually done in a similar way to immuno-fluorescence, using an unconjugated primary antibody followed by a tagged secondary antibody against the primary. In this case the tag is usually a colloidal gold particle instead of a fluorophore. Therefore it is quite straightforward to adapt an immuno-fluorescence procedure for SEM, as long as certain precautions are followed, as discussed here. Progressing from immuno-fluorescence, which essentially only indicates the position of a protein within the volume of a cell, to immuno-SEM, puts the labeling into the context of cellular structures. The principles and practices of sample preparation, labeling and imaging are described here.

  16. Cryo-electron Microscopy Analysis of Structurally Heterogeneous Macromolecular Complexes.

    Science.gov (United States)

    Jonić, Slavica

    2016-01-01

    Cryo-electron microscopy (cryo-EM) has for a long time been a technique of choice for determining structure of large and flexible macromolecular complexes that were difficult to study by other experimental techniques such as X-ray crystallography or nuclear magnetic resonance. However, a fast development of instruments and software for cryo-EM in the last decade has allowed that a large range of complexes can be studied by cryo-EM, and that their structures can be obtained at near-atomic resolution, including the structures of small complexes (e.g., membrane proteins) whose size was earlier an obstacle to cryo-EM. Image analysis to identify multiple coexisting structures in the same specimen (multiconformation reconstruction) is now routinely done both to solve structures at near-atomic resolution and to study conformational dynamics. Methods for multiconformation reconstruction and latest examples of their applications are the focus of this review.

  17. Electron Microscopy Analysis of the Nucleolus of Trypanosoma cruzi

    Science.gov (United States)

    López-Velázquez, Gabriel; Hernández, Roberto; López-Villaseñor, Imelda; Reyes-Vivas, Horacio; Segura-Valdez, María De L.; Jiménez-García, Luis F.

    2005-08-01

    The nucleolus is the main site for synthesis and processing of ribosomal RNA in eukaryotes. In mammals, plants, and yeast the nucleolus has been extensively characterized by electron microscopy, but in the majority of the unicellular eukaryotes no such studies have been performed. Here we used ultrastructural cytochemical and immunocytochemical techniques as well as three-dimensional reconstruction to analyze the nucleolus of Trypanosoma cruzi, which is an early divergent eukaryote of medical importance. In T. cruzi epimastigotes the nucleolus is a spherical intranuclear ribonucleoprotein organelle localized in a relatively central position within the nucleus. Dense fibrillar and granular components but not fibrillar centers were observed. In addition, nuclear bodies resembling Cajal bodies were observed associated to the nucleolus in the surrounding nucleoplasm. Our results provide additional morphological data to better understand the synthesis and processing of the ribosomal RNA in kinetoplastids.

  18. In situ and operando transmission electron microscopy of catalytic materials

    DEFF Research Database (Denmark)

    Crozier, Peter A.; Hansen, Thomas Willum

    2015-01-01

    Catalytic nanomaterials play a major role in chemical conversions and energy transformations. Understanding how materials control and regulate surface reactions is a major objective for fundamental research on heterogeneous catalysts. In situ environmental transmission electron microscopy (ETEM......) is a powerful technique for revealing the atomic structures of materials at elevated temperatures in the presence of reactive gases. This approach can allow the structure-reactivity relations underlying catalyst functionality to be investigated. Thus far, ETEM has been limited by the absence of in situ...... measurements of gas-phase catalytic products. To overcome this deficiency, operando TEM techniques are being developed that combine atomic characterization with the simultaneous measurement of catalytic products. This article provides a short review of the current status and major developments...

  19. Variability of Protein Structure Models from Electron Microscopy.

    Science.gov (United States)

    Monroe, Lyman; Terashi, Genki; Kihara, Daisuke

    2017-04-04

    An increasing number of biomolecular structures are solved by electron microscopy (EM). However, the quality of structure models determined from EM maps vary substantially. To understand to what extent structure models are supported by information embedded in EM maps, we used two computational structure refinement methods to examine how much structures can be refined using a dataset of 49 maps with accompanying structure models. The extent of structure modification as well as the disagreement between refinement models produced by the two computational methods scaled inversely with the global and the local map resolutions. A general quantitative estimation of deviations of structures for particular map resolutions are provided. Our results indicate that the observed discrepancy between the deposited map and the refined models is due to the lack of structural information present in EM maps and thus these annotations must be used with caution for further applications. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Electron Diffraction and High-Resolution Electron Microscopy of Mineral Structures

    Science.gov (United States)

    Nord, Gordon L., Jr.

    This book is a well-written English translation of the original 1981 Russian edition, Strukturnoye issledovaniye mineralov metodami mikrodifraktsii i elechtronnoi mikroskopii vysokogo razresheniya. The 1987 English version has been extensively updated and includes references up to 1986. The book is essentially a text on the theoretical and experimental aspects of transmission electron microscopy and has chapters on the reciprocal lattice, electron diffraction (both kinematic and dynamic), and high-resolution electron microscopy.Electron diffraction is emphasized, especially its use for structure analysis of poorly crystalline and fine-grained phases not readily determined by the more exact X ray diffraction method. Two methods of electron diffraction are discussed: selected area electron diffraction (SAED) and oblique-texture electron diffraction (OTED); the latter technique is rarely used in the west and is never discussed in western electron microscopy texts. A SAED pattern is formed by isolating a small micrometer-size area with an aperture and obtaining single-crystal patterns from the diffracted beams. By tilting the sample and obtaining many patterns, a complete picture of the reciprocal lattice can be taken. An OTED pattern is formed when the incident electron beam passes through an inclined preparation consisting of a great number of thin platy crystals lying normal to the texture axis (axis normal to the support grid). To form an OTED pattern, the plates must all lie on a common face, such as a basal plane in phyllosilicates. Upon tilting the plates, an elliptical powder diffraction pattern is formed. Intensities measured from these patterns are used for a structural analysis of the platy minerals.

  1. Studying the Kinetics of Crystalline Silicon Nanoparticle Lithiation with In Situ Transmission Electron Microscopy

    KAUST Repository

    McDowell, Matthew T.

    2012-09-04

    In situ transmission electron microscopy (TEM) is used to study the electrochemical lithiation of high-capacity crystalline Si nanoparticles for use in Li-ion battery anodes. The lithiation reaction slows down as it progresses into the particle interior, and analysis suggests that this behavior is due not to diffusion limitation but instead to the influence of mechanical stress on the driving force for reaction. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Localization of fluorescently labeled structures in frozen-hydrated samples using integrated light electron microscopy

    NARCIS (Netherlands)

    Faas, F.G.A.; Bárcena, M.A.; Agronskaia, A.V.; Gerritsen, H.C.; Moscicka, K.B.; Diebolder, C.A.; Driel, L.F.; Limpens, R.W.A.L.; Bos, E.; Ravelli, R.B.G.; Koning, R.I.; Koster, A.J.

    2013-01-01

    Correlative light and electron microscopy is an increasingly popular technique to study complex biological systems at various levels of resolution. Fluorescence microscopy can be employed to scan large areas to localize regions of interest which are then analyzed by electron microscopy to obtain

  3. Transmission electron microscopy for the evaluation and optimization of crystal growth

    OpenAIRE

    Stevenson, Hilary P.; Lin, Guowu; Barnes, Christopher O.; Sutkeviciute, Ieva; Krzysiak, Troy; Weiss, Simon C.; Reynolds, Shelley; Wu, Ying; Nagarajan, Veeranagu; Makhov, Alexander M.; Lawrence, Robert; Lamm, Emily; Clark, Lisa; Gardella, Timothy J.; Hogue, Brenda G.

    2016-01-01

    In this article, the potential of transmission electron microscopy to assist in the process of generating well diffracting crystals for conventional crystallography, as well as for free-electron laser and micro-electron diffraction applications, is demonstrated.

  4. From the physics of secondary electron emission to image contrasts in scanning electron microscopy.

    Science.gov (United States)

    Cazaux, Jacques

    2012-01-01

    Image formation in scanning electron microscopy (SEM) is a combination of physical processes, electron emissions from the sample, and of a technical process related to the detection of a fraction of these electrons. For the present survey of image contrasts in SEM, simplified considerations in the physics of the secondary electron emission yield, δ, are combined with the effects of a partial collection of the emitted secondary electrons. Although some consideration is initially given to the architecture of modern SEM, the main attention is devoted to the material contrasts with the respective roles of the sub-surface and surface compositions of the sample, as well as with the roles of the field effects in the vacuum gap. The recent trends of energy filtering in normal SEM and the reduction of the incident energy to a few electron volts in very low-energy electron microscopy are also considered. For an understanding by the SEM community, the mathematical expressions are explained with simple physical arguments.

  5. Electron microscopy by specimen design: application to strain measurements.

    Science.gov (United States)

    Cherkashin, Nikolay; Denneulin, Thibaud; Hÿtch, Martin J

    2017-09-29

    A bewildering number of techniques have been developed for transmission electron microscopy (TEM), involving the use of ever more complex combinations of lens configurations, apertures and detector geometries. In parallel, the developments in the field of ion beam instruments have modernized sample preparation and enabled the preparation of various types of materials. However, the desired final specimen geometry is always almost the same: a thin foil of uniform thickness. Here we will show that judicious design of specimen geometry can make all the difference and that experiments can be carried out on the most basic electron microscope and in the usual imaging modes. We propose two sample preparation methods that allow the formation of controlled moiré patterns for general monocrystalline structures in cross-section and at specific sites. We developed moiré image treatment algorithms using an absolute correction of projection lens distortions of a TEM that allows strain measurements and mapping with a nanometer resolution and 10-4 precision. Imaging and diffraction techniques in other fields may in turn benefit from this technique in perspective.

  6. The characterization of nanoparticles using analytical electron microscopy

    Science.gov (United States)

    Hill, Whitney B.

    2011-06-01

    Nanoparticles are often overlooked during routine trace evidence analyses because of their small size and the degree of difficulty needed to efficiently characterize them. However, analytical electron microscopy (AEM) enables the characterization and/or identification of nanoparticles because of its high magnification capability, the ability to gather elemental data and also the ability to determine the internal structure of a single nanoparticles(1). There is a wide variety of natural and manufactured nanoparticles that are prominent within the environment and their presence becomes very valuable in the absence of larger particles. The combustion of materials produces by-products such as nano-sized carbon soot, fumes, fly ash and gun-shot residue (GSR). Using AEM, nano-sized carbon soot, fumes, fly ash and GSR can not only be distinguished from other nanoparticles within the environment but can also be distinguished from each other because of differences in morphology, elemental composition, and internal structure. The elemental information gathered from combustion by-products during AEM analysis can also give an indication of the original source material. Other nanoparticles such as paint pigments and fillers can also be characterized by AEM using morphology, electron diffraction and elemental composition.

  7. Atomic-scale electron microscopy at ambient pressure

    Energy Technology Data Exchange (ETDEWEB)

    Creemer, J.F. [DIMES-ECTM, Delft University of Technology, P.O. Box 5053, 2600 GB Delft (Netherlands)], E-mail: j.f.creemer@tudelft.nl; Helveg, S. [Haldor Topsoe A/S, Nymollevej 55, DK-2800 Kgs. Lyngby (Denmark); Hoveling, G.H. [DEMO, Delft University of Technology, P.O. Box 5031, 2600 GA Delft (Netherlands); Ullmann, S.; Molenbroek, A.M. [Haldor Topsoe A/S, Nymollevej 55, DK-2800 Kgs. Lyngby (Denmark); Sarro, P.M. [DIMES-ECTM, Delft University of Technology, P.O. Box 5053, 2600 GB Delft (Netherlands); Zandbergen, H.W. [Kavli Institute of NanoScience, HREM, Delft University of Technology, P.O. Box 5046, 2600 GA Delft (Netherlands)

    2008-08-15

    We demonstrate a novel nanoreactor for performing atomic-resolution environmental transmission electron microscopy (ETEM) of nanostructured materials during exposure to gases at ambient pressures and elevated temperatures. The nanoreactor is a microelectromechanical system (MEMS) and is functionalized with a micrometer-sized gas-flow channel, electron-transparent windows and a heating device. It fits into the tip of a dedicated sample holder that can be used in a normal CM microscope of Philips/FEI Company. The nanoreactor performance was demonstrated by ETEM imaging of a Cu/ZnO catalyst for methanol synthesis during exposure to hydrogen. Specifically, the nanoreactor facilitated the direct observation of Cu nanocrystal growth and mobility on a sub-second time scale during heating to 500 deg. C and exposure to 1.2 bar of H{sub 2}. For the same gas reaction environment, ETEM images show atomic lattice fringes in the Cu nanocrystals with spacing of 0.18 nm, attesting the spatial resolution limit of the system. The nanoreactor concept opens up new possibilities for in situ studies of nanomaterials and the ways they interact with their ambient working environment in diverse areas, such as heterogeneous catalysis, electrochemistry, nanofabrication, materials science and biology.

  8. Thin dielectric film thickness determination by advanced transmission electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Diebold, A.C.; Foran, B.; Kisielowski, C.; Muller, D.; Pennycook, S.; Principe, E.; Stemmer, S.

    2003-09-01

    High Resolution Transmission Electron Microscopy (HR-TEM) has been used as the ultimate method of thickness measurement for thin films. The appearance of phase contrast interference patterns in HR-TEM images has long been confused as the appearance of a crystal lattice by non-specialists. Relatively easy to interpret crystal lattice images are now directly observed with the introduction of annular dark field detectors for scanning TEM (STEM). With the recent development of reliable lattice image processing software that creates crystal structure images from phase contrast data, HR-TEM can also provide crystal lattice images. The resolution of both methods was steadily improved reaching now into the sub Angstrom region. Improvements in electron lens and image analysis software are increasing the spatial resolution of both methods. Optimum resolution for STEM requires that the probe beam be highly localized. In STEM, beam localization is enhanced by selection of the correct aperture. When STEM measurement is done using a highly localized probe beam, HR-TEM and STEM measurement of the thickness of silicon oxynitride films agree within experimental error. In this paper, the optimum conditions for HR-TEM and STEM measurement are discussed along with a method for repeatable film thickness determination. The impact of sample thickness is also discussed. The key result in this paper is the proposal of a reproducible method for film thickness determination.

  9. Ondrej Krivanek: A pioneering visionary in electron microscopy.

    Science.gov (United States)

    Lovejoy, Tracy; Rez, Peter; Dellby, Niklas

    2017-09-01

    This article is a short biographical sketch of the life and times of Ondrej Krivanek. The story starts with his early days in Prague, Czechia, and briefly outlines various events from a PhD in Cambridge to post-docs in Kyoto, Bell Labs, and building his first spectrometer at UC Berkeley. Ondrej's pioneering contributions to electron microscopy as Assistant Professor at Arizona State University and later as Director of R&D at Gatan are covered, as well as his return to academia and focusing on aberration correction. The story wraps up with the founding of Nion, the early success of the Nion aberration correctors, and subsequent progress such as building a complete cutting-edge electron microscope and later a record-breaking monochromator. Ondrej continues to be actively involved in design and in running Nion, and while this article ends at the present, further breakthroughs can be expected from him. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Time Resolved Phase Transitions via Dynamic Transmission Electron Microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Reed, B W; Armstrong, M R; Blobaum, K J; Browning, N D; Burnham, A K; Campbell, G H; Gee, R; Kim, J S; King, W E; Maiti, A; Piggott, W T; Torralva, B R

    2007-02-22

    The Dynamic Transmission Electron Microscope (DTEM) project is developing an in situ electron microscope with nanometer- and nanosecond-scale resolution for the study of rapid laser-driven processes in materials. We report on the results obtained in a year-long LDRD-supported effort to develop DTEM techniques and results for phase transitions in molecular crystals, reactive multilayer foils, and melting and resolidification of bismuth. We report the first in situ TEM observation of the HMX {beta}-{delta} phase transformation in sub-{micro}m crystals, computational results suggesting the importance of voids and free surfaces in the HMX transformation kinetics, and the first electron diffraction patterns of intermediate states in fast multilayer foil reactions. This project developed techniques which are applicable to many materials systems and will continue to be employed within the larger DTEM effort.

  11. Correlated cryo-fluorescence and cryo-electron microscopy with high spatial precision and improved sensitivity

    Energy Technology Data Exchange (ETDEWEB)

    Schorb, Martin [Structural and Computational Biology Unit, European Molecular Biology Laboratory, D-69117 Heidelberg (Germany); Briggs, John A.G., E-mail: john.briggs@embl.de [Structural and Computational Biology Unit, European Molecular Biology Laboratory, D-69117 Heidelberg (Germany); Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, D-69117 Heidelberg (Germany)

    2014-08-01

    Performing fluorescence microscopy and electron microscopy on the same sample allows fluorescent signals to be used to identify and locate features of interest for subsequent imaging by electron microscopy. To carry out such correlative microscopy on vitrified samples appropriate for structural cryo-electron microscopy it is necessary to perform fluorescence microscopy at liquid-nitrogen temperatures. Here we describe an adaptation of a cryo-light microscopy stage to permit use of high-numerical aperture objectives. This allows high-sensitivity and high-resolution fluorescence microscopy of vitrified samples. We describe and apply a correlative cryo-fluorescence and cryo-electron microscopy workflow together with a fiducial bead-based image correlation procedure. This procedure allows us to locate fluorescent bacteriophages in cryo-electron microscopy images with an accuracy on the order of 50 nm, based on their fluorescent signal. It will allow the user to precisely and unambiguously identify and locate objects and events for subsequent high-resolution structural study, based on fluorescent signals. - Highlights: • Workflow for correlated cryo-fluorescence and cryo-electron microscopy. • Cryo-fluorescence microscopy setup incorporating a high numerical aperture objective. • Fluorescent signals located in cryo-electron micrographs with 50 nm spatial precision.

  12. Electron Microscopy Observation of Biomineralization within Wood Tissues of Kurogaki

    Directory of Open Access Journals (Sweden)

    Kazue Tazaki

    2017-07-01

    Full Text Available Interactions between minerals and microorganisms play a crucial role in living wood tissues. However, living wood tissues have never been studied in the field. Fortunately, we found several kurogaki (black persimmon; Diospyros kaki trees at Tawara in Kanazawa, Ishikawa, Japan. Here, we report the characterization of kurogaki based on scanning electron microscopy equipped with energy-dispersive spectroscopy (SEM-EDS and transmission electron microscopy (TEM, associated with inductively coupled plasma-mass spectrometry (ICP-MS analyses, X-ray fluorescence analyses (XRF and X-ray powder diffraction (XRD analyses. This study aims to illustrate the ability of various microorganisms associated with biominerals within wood tissues of kurogaki, as shown by SEM-EDS elemental content maps and TEM images. Kurogaki grows very slowly and has extremely hard wood, known for its striking black and beige coloration, referred to as a “peacock pattern”. However, the scientific data for kurogaki are very limited. The black “peacock pattern” of the wood mainly comprises cellulose and high levels of crystal cristobalite. As per the XRD results, the black taproot contains mineralized 7 Å clays (kaolinite, cellulose, apatite and cristobalite associated with many microorganisms. The chemical compositions of the black and beige portions of the black persimmon tree were obtained by ICP-MS analyses. Particular elements such as abundant Ca, Mg, K, P, Mn, Ba, S, Cl, Fe, Na, and Al were concentrated in the black region, associated with Pb and Sr elements. SEM-EDS semi-qualitative analyses of kurogaki indicated an abundance of P and Ca in microorganisms in the black region, associated with Pb, Sr, S, Mn, and Mg elements. On the other hand, XRF and XRD mineralogical data showed that fresh andesite, weathered andesite, and the soils around the roots of kurogaki correlate with biomineralization of the black region in kurogaki roots, showing clay minerals (kaolinite and

  13. Low-energy electron microscopy on two-dimensional systems : : growth, potentiometry and band structure mapping

    NARCIS (Netherlands)

    Kautz, Jaap

    2015-01-01

    Low Energy Electron Microscopy (LEEM) is a microscopy technique typically used to study surface processes. The sample is illuminated with a parallel beam of electrons under normal incidence and the reflected electrons are projected onto a pixelated detector, where an image is formed. In the first

  14. Automated Quantitative Rare Earth Elements Mineralogy by Scanning Electron Microscopy

    Science.gov (United States)

    Sindern, Sven; Meyer, F. Michael

    2016-09-01

    Increasing industrial demand of rare earth elements (REEs) stems from the central role they play for advanced technologies and the accelerating move away from carbon-based fuels. However, REE production is often hampered by the chemical, mineralogical as well as textural complexity of the ores with a need for better understanding of their salient properties. This is not only essential for in-depth genetic interpretations but also for a robust assessment of ore quality and economic viability. The design of energy and cost-efficient processing of REE ores depends heavily on information about REE element deportment that can be made available employing automated quantitative process mineralogy. Quantitative mineralogy assigns numeric values to compositional and textural properties of mineral matter. Scanning electron microscopy (SEM) combined with a suitable software package for acquisition of backscatter electron and X-ray signals, phase assignment and image analysis is one of the most efficient tools for quantitative mineralogy. The four different SEM-based automated quantitative mineralogy systems, i.e. FEI QEMSCAN and MLA, Tescan TIMA and Zeiss Mineralogic Mining, which are commercially available, are briefly characterized. Using examples of quantitative REE mineralogy, this chapter illustrates capabilities and limitations of automated SEM-based systems. Chemical variability of REE minerals and analytical uncertainty can reduce performance of phase assignment. This is shown for the REE phases parisite and synchysite. In another example from a monazite REE deposit, the quantitative mineralogical parameters surface roughness and mineral association derived from image analysis are applied for automated discrimination of apatite formed in a breakdown reaction of monazite and apatite formed by metamorphism prior to monazite breakdown. SEM-based automated mineralogy fulfils all requirements for characterization of complex unconventional REE ores that will become

  15. Transmission electron microscopy analysis of corroded metal waste forms.

    Energy Technology Data Exchange (ETDEWEB)

    Dietz, N. L.

    2005-04-15

    This report documents the results of analyses with transmission electron microscopy (TEM) combined with energy dispersive X-ray spectroscopy (EDS) and selected area electron diffraction (ED) of samples of metallic waste form (MWF) materials that had been subjected to various corrosion tests. The objective of the TEM analyses was to characterize the composition and microstructure of surface alteration products which, when combined with other test results, can be used to determine the matrix corrosion mechanism. The examination of test samples generated over several years has resulted in refinements to the TEM sample preparation methods developed to preserve the orientation of surface alteration layers and the underlying base metal. The preservation of microstructural spatial relationships provides valuable insight for determining the matrix corrosion mechanism and for developing models to calculate radionuclide release in repository performance models. The TEM results presented in this report show that oxide layers are formed over the exposed steel and intermetallic phases of the MWF during corrosion in aqueous solutions and humid air at elevated temperatures. An amorphous non-stoichiometric ZrO{sub 2} layer forms at the exposed surfaces of the intermetallic phases, and several nonstoichiometric Fe-O layers form over the steel phases in the MWF. These oxide layers adhere strongly to the underlying metal, and may be overlain by one or more crystalline Fe-O phases that probably precipitated from solution. The layer compositions are consistent with a corrosion mechanism of oxidative dissolution of the steel and intermetallic phases. The layers formed on the steel and intermetallic phases form a continuous layer over the exposed waste form, although vertical splits in the layer and corrosion in pits and crevices were seen in some samples. Additional tests and analyses are needed to verify that these layers passivate the underlying metals and if passivation can break

  16. Customized patterned substrates for highly versatile correlative light-scanning electron microscopy

    Science.gov (United States)

    Benedetti, Lorena; Sogne, Elisa; Rodighiero, Simona; Marchesi, Davide; Milani, Paolo; Francolini, Maura

    2014-01-01

    Correlative light electron microscopy (CLEM) combines the advantages of light and electron microscopy, thus making it possible to follow dynamic events in living cells at nanometre resolution. Various CLEM approaches and devices have been developed, each of which has its own advantages and technical challenges. We here describe our customized patterned glass substrates, which improve the feasibility of correlative fluorescence/confocal and scanning electron microscopy. PMID:25391455

  17. Destructive effects induced by the electron beam in scanning electron microscopy

    Science.gov (United States)

    Popescu, M. C.; Bita, B. I.; Banu, M. A.; Tomescu, R. M.

    2016-12-01

    The Scanning Electron Microscopy has been validated by its impressive imaging and reliable measuring as an essential characterization tool for a variety of applications and research fields. This paper is a comprehensive study dedicated to the undesirable influence of the accelerated electron beam associated with the dielectric materials, sensitive structures or inappropriate sample manipulation. Depending on the scanning conditions, the electron beam may deteriorate the investigated sample due to the extended focusing or excessive high voltage and probe current applied on vulnerable configurations. Our aim is to elaborate an instructive material for improved SEM visualization capabilities by overcoming the specific limitations of the technique. Particular examination and measuring methods are depicted along with essential preparation and manipulation procedures in order to protect the integrity of the sample. Various examples are mentioned and practical solutions are described in respect to the general use of the electron microscope.

  18. Atomic-resolution transmission electron microscopy of electron beam–sensitive crystalline materials

    KAUST Repository

    Zhang, Daliang

    2018-01-18

    High-resolution imaging of electron beam-sensitive materials is one of the most difficult applications of transmission electron microscopy (TEM). The challenges are manifold, including the acquisition of images with extremely low beam doses, the time-constrained search for crystal zone axes, the precise image alignment, and the accurate determination of the defocus value. We develop a suite of methods to fulfill these requirements and acquire atomic-resolution TEM images of several metal organic frameworks that are generally recognized as highly sensitive to electron beams. The high image resolution allows us to identify individual metal atomic columns, various types of surface termination, and benzene rings in the organic linkers. We also apply our methods to other electron beam–sensitive materials, including the organic-inorganic hybrid perovskite CH3NH3PbBr3.

  19. Analytical electron microscopy of biogenic and inorganic carbonates

    Science.gov (United States)

    Blake, David F.

    1989-01-01

    In the terrestrial sedimentary environment, the mineralogically predominant carbonates are calcite-type minerals (rhombohedral carbonates) and aragonite-type minerals (orthorhombic carbonates). Most common minerals precipitating either inorganically or biogenically are high magnesium calcite and aragonite. High magnesium calcite (with magnesium carbonate substituting for more than 7 mole percent of the calcium carbonate) is stable only at temperatures greater than 700 C or thereabouts, and aragonite is stable only at pressures exceeding several kilobars of confining pressure. Therefore, these carbonates are expected to undergo chemical stabilization in the diagenetic environment to ultimately form stable calcite and dolomite. Because of the strong organic control of carbonate deposition in organisms during biomineralization, the microchemistry and microstructure of invertebrate skeletal material is much different than that present in inorganic carbonate cements. The style of preservation of microstructural features in skeletal material is therefore often quite distinctive when compared to that of inorganic carbonate even though wholesale recrystallization of the sediment has taken place. Microstructural and microchemical comparisons are made between high magnesium calcite echinoderm skeletal material and modern inorganic high magnesium calcite inorganic cements, using analytical electron microscopy and related techniques. Similar comparisons are made between analogous materials which have undergone stabilization in the diagenetic environment. Similar analysis schemes may prove useful in distinguishing between biogenic and inorganic carbonates in returned Martian carbonate samples.

  20. Cryo-planing for cryo-scanning electron microscopy.

    Science.gov (United States)

    Nijsse, J; van Aelst, A C

    1999-01-01

    In the past decade, investigators of cryo-planing for low-temperature scanning electron microscopy (cryo-SEM) have developed techniques that enable observations of flat sample surfaces. This study reviews these sample preparation techniques, compares and contrasts their results, and introduces modifications that improve results from cryo-planing. A prerequisite for all successful cryo-planing required a stable attachment of the specimen to a holder. In most cases, clamping with a screw mechanism and using indium as space-filler sufficed. Once this problem was solved, any of three existing cryo-planing methods could be used to provide successful results: cryo-milling, microtomy in a cold room, and cryo-ultramicrotomy. This study introduces modifications to the cryo-planing technique that produces flat surfaces of any desired plane through a specimen. These flat surfaces of frozen, fully hydrated samples can be used to improve observations from cryo-SEM as well as to enhance results from x-ray microanalysis and (digital) image analysis. Cryo-planing results of chrysanthemum (Dendranthema x grandiflorum Tzvelev) stems, hazel (Corylus avelane L.) stems, and repeseed (Brassica napus L.) pistils are presented to illustrate the use of the planing method on fibrous, hard, and delicate materials, respectively.

  1. TRANSMISSION ELECTRON MICROSCOPY STUDY OF HELIUM BEARING FUSION WELDS

    Energy Technology Data Exchange (ETDEWEB)

    Tosten, M; Michael Morgan, M

    2008-12-12

    A transmission electron microscopy (TEM) study was conducted to characterize the helium bubble distributions in tritium-charged-and-aged 304L and 21Cr-6Ni-9Mn stainless steel fusion welds containing approximately 150 appm helium-3. TEM foils were prepared from C-shaped fracture toughness test specimens containing {delta} ferrite levels ranging from 4 to 33 volume percent. The weld microstructures in the low ferrite welds consisted mostly of austenite and discontinuous, skeletal {delta} ferrite. In welds with higher levels of {delta} ferrite, the ferrite was more continuous and, in some areas of the 33 volume percent sample, was the matrix/majority phase. The helium bubble microstructures observed were similar in all samples. Bubbles were found in the austenite but not in the {delta} ferrite. In the austenite, bubbles had nucleated homogeneously in the grain interiors and heterogeneously on dislocations. Bubbles were not found on any austenite/austenite grain boundaries or at the austenite/{delta} ferrite interphase interfaces. Bubbles were not observed in the {delta} ferrite because of the combined effects of the low solubility and rapid diffusion of tritium through the {delta} ferrite which limited the amount of helium present to form visible bubbles.

  2. Non-thermal plasma mills bacteria: Scanning electron microscopy observations

    Energy Technology Data Exchange (ETDEWEB)

    Lunov, O., E-mail: lunov@fzu.cz; Churpita, O.; Zablotskii, V.; Jäger, A.; Dejneka, A. [Institute of Physics AS CR, Prague 18221 (Czech Republic); Deyneka, I. G.; Meshkovskii, I. K. [St. Petersburg State University of Information Technologies, Mechanics and Optics, St. Petersburg 197101 (Russian Federation); Syková, E. [Institute of Experimental Medicine AS CR, Prague 14220 (Czech Republic); Kubinová, Š. [Institute of Physics AS CR, Prague 18221 (Czech Republic); Institute of Experimental Medicine AS CR, Prague 14220 (Czech Republic)

    2015-02-02

    Non-thermal plasmas hold great promise for a variety of biomedical applications. To ensure safe clinical application of plasma, a rigorous analysis of plasma-induced effects on cell functions is required. Yet mechanisms of bacteria deactivation by non-thermal plasma remain largely unknown. We therefore analyzed the influence of low-temperature atmospheric plasma on Gram-positive and Gram-negative bacteria. Using scanning electron microscopy, we demonstrate that both Gram-positive and Gram-negative bacteria strains in a minute were completely destroyed by helium plasma. In contrast, mesenchymal stem cells (MSCs) were not affected by the same treatment. Furthermore, histopathological analysis of hematoxylin and eosin–stained rat skin sections from plasma–treated animals did not reveal any abnormalities in comparison to control ones. We discuss possible physical mechanisms leading to the shred of bacteria under non-thermal plasma irradiation. Our findings disclose how helium plasma destroys bacteria and demonstrates the safe use of plasma treatment for MSCs and skin cells, highlighting the favorability of plasma applications for chronic wound therapy.

  3. Life cycle of phytoreoviruses visualized by electron microscopy and tomography

    Directory of Open Access Journals (Sweden)

    Naoyuki eMiyazaki

    2013-10-01

    Full Text Available Rice dwarf virus (RDV and Rice gall dwarf virus (RGDV, members of the genus Phytoreovirus in the family Reoviridae, are known as agents of rice disease, because their spread results in substantial economic damage in many Asian countries. These viruses are transmitted via insect vectors, and they multiply both in the plants and in the insect vectors. Structural information about the viruses and their interactions with cellular components in the life cycle are essential for understanding viral infection and replication mechanisms. The life cycle of the viruses involves various cellular events such as cell entry, synthesis of viral genome and proteins, assembly of viral components, viral egress from infected cells, and intra- and inter-cellular transports. This review focuses on the major events underlying the life cycle of phytoreoviruses, which has been visualized by various EM imaging techniques, including cryo-electron microscopy and tomography, and demonstrates the advantage of the advanced EM imaging techniques to investigate the viral infection and replication mechanisms.

  4. Analysis of virus textures in transmission electron microscopy images.

    Science.gov (United States)

    Nanni, Loris; Paci, Michelangelo; Caetano Dos Santos, Florentino Luciano; Brahnam, Sheryl; Hyttinen, Jari

    2014-01-01

    In this paper we propose an ensemble of texture descriptors for analyzing virus textures in transmission electron microscopy images. Specifically, we present several novel multi-quinary (MQ) codings of local binary pattern (LBP) variants: the MQ version of the dense LBP, the MQ version of the rotation invariant co-occurrence among adjacent LBPs, and the MQ version of the LBP histogram Fourier. To reduce computation time as well as to improve performance, a feature selection approach is utilized to select the thresholds used in the MQ approaches. In addition, we propose new variants of descriptors where two histograms, instead of the standard one histogram, are produced for each descriptor. The two histograms (one for edge pixels and the other for non-edge pixels) are calculated for training two different SVMs, whose results are then combined by sum rule. We show that a bag of features approach works well with this problem. Our experiments, using a publicly available dataset of 1500 images with 15 classes and same protocol as in previous works, demonstrate the superiority of our new proposed ensemble of texture descriptors. The MATLAB code of our approach is available at https://www.dei.unipd.it/node/2357.

  5. Photoacoustic microscopy of electronic acupuncture (EA) effect in small animals.

    Science.gov (United States)

    Yang, Jinge; Wu, Dan; Tang, Yong; Jiang, Huabei

    2017-02-01

    Acupuncture has been an effective treatment for various pain in China for several thousand years. However, the mechanisms underlying this mysterious ancient healing are still largely unknown. Here we applied photoacoustic microscopy (PAM) to investigate brain hemodynamic changes in response to electronic acupuncture (EA) at ST36 (Zusanli). Due to the high optical absorption of blood at 532 nm, PAM could sensitively probe changes in hemoglobin concentration (HbT, i.e., cerebral blood volume [CBV]) of cortical regions in high resolution. Six healthy mice were stimulated at the acupoint and three healthy mice were stimulated at sham points. Remarkable CBV changes in sensorimotor and retrosplenial agranular cortex were observed. Results showed the potential of PAM as a visualization tool to study the acupuncture effect on brain hemodynamics in animal models. (a) Schematic showing the stimulation points. (b) B-scan images overlaid with mouse atlas. (c) & (d) Statistical results of CBV changes from cortical regions. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Light and transmission electron microscopy of immature camelus dromedarius oocyte.

    Science.gov (United States)

    Nili, H; Mesbah, F; Kafi, M; Nasr Esfahani, M H

    2004-08-01

    In order to provide a consistent system for laboratory production of embryos, the characteristics of immature camel oocyte must first be described. The objective of this study was to define ultrastructural features of immature camel oocyte. Ovaries were obtained from camels at a local abattoir, and then transported to the laboratory within 2 h. Camelus cumulus oocyte complexes (COCs) were aspirated from 2-6 mm follicles using a 22-gauge needle. Excellent and good quality COCs were selected and prepared for transmission electron microscopy study using a cavity slide. The fine structure of camel oocyte is morphologically similar to that of other mammalian oocytes. However, some minor differences exist between COC of camel and other mammalian species. Different size and shape of membrane-bound vesicles, lipid droplet, mitochondria and cortical granules were distributed throughout the ooplasm. Discrete or in association with endoplasmic reticulum, Golgi complexes were observed in the periphery of the oocytes. The majority of the oocytes were in the germinal vesicle stage.

  7. Scanning electron microscopy of eggs of Sabethes cyaneus.

    Science.gov (United States)

    Santos-Mallet, Jacenir; Sarmento, Juliana Soares; Alencar, Jeronimo; Müller, Gerson Azulim; Oliveira, Eliana Medeiros; Foster, Woodbridge A; Marcondes, Carlos Brisola

    2013-03-01

    Mosquitoes of the Neotropical genus Sabethes, some species of which are yellow fever vectors, most often develop through the immature stages in tree holes. Sabethes eggs have not been previously characterized using scanning electron microscopy. Eggs of Sabethes cyaneus (length: 349.6 +/- 2.7 microm; width: 172.6 +/- 1.14 microm; n = 10) are almost biconical when examined from the top. From a lateral perspective 2 surfaces can be seen. One surface is smooth and more convex, whereas the other is less convex and partially covered by a network from which many fungiform tubercles arise. The micropyle is situated on the smooth surface of the pointed anterior tip and is surrounded by an irregular row of tubercles, some of which are leaf shaped. No structures possibly involved in adhesion to surfaces are visible. When hatching, the egg splits dorsoventrally approximately two-thirds of the length from the anterior end. The tubercles appear to be water repellent, and the more convex/smoother surface is downturned, and this position on water was confirmed by direct observation. The eggs float free on the water surface.

  8. Scanning electron microscopy applied to seed-borne fungi examination.

    Science.gov (United States)

    Alves, Marcelo de Carvalho; Pozza, Edson Ampélio

    2009-07-01

    The aim of this study was to test the standard scanning electron microscopy (SEM) as a potential alternative to study seed-borne fungi in seeds, by two different conditions of blotter test and water restriction treatment. In the blotter test, seeds were subjected to conditions that enabled pathogen growth and expression, whereas the water restriction method consisted in preventing seed germination during the incubation period, resulting in the artificial inoculation of fungi. In the first condition, seeds of common bean (Phaseolus vulgaris L.), maize (Zea mays L.), and cotton (Gossypium hirsutum L.) were submitted to the standard blotter test and then prepared and observed with SEM. In the second condition, seeds of cotton (G. hirsutum), soybean (Glycine max L.), and common bean (P. vulgaris L.) were, respectively, inoculated with Colletotrichum gossypii var. cephalosporioides, Colletotrichum truncatum, and Colletotrichum lindemuthianum by the water restriction technique, followed by preparation and observation with SEM. The standard SEM methodology was adopted to prepare the specimens. Considering the seeds submitted to the blotter test, it was possible to identify Fusarium sp. on maize, C. gossypii var. cephalosporioides, and Fusarium oxysporum on cotton, Aspergillus flavus, Penicillium sp., Rhizopus sp., and Mucor sp. on common bean. Structures of C. gossypii var. cephalosporioides, C. truncatum, and C. lindemuthianum were observed in the surface of inoculated seeds. (c) 2009 Wiley-Liss, Inc.

  9. Residual Deconvolutional Networks for Brain Electron Microscopy Image Segmentation.

    Science.gov (United States)

    Fakhry, Ahmed; Zeng, Tao; Ji, Shuiwang

    2017-02-01

    Accurate reconstruction of anatomical connections between neurons in the brain using electron microscopy (EM) images is considered to be the gold standard for circuit mapping. A key step in obtaining the reconstruction is the ability to automatically segment neurons with a precision close to human-level performance. Despite the recent technical advances in EM image segmentation, most of them rely on hand-crafted features to some extent that are specific to the data, limiting their ability to generalize. Here, we propose a simple yet powerful technique for EM image segmentation that is trained end-to-end and does not rely on prior knowledge of the data. Our proposed residual deconvolutional network consists of two information pathways that capture full-resolution features and contextual information, respectively. We showed that the proposed model is very effective in achieving the conflicting goals in dense output prediction; namely preserving full-resolution predictions and including sufficient contextual information. We applied our method to the ongoing open challenge of 3D neurite segmentation in EM images. Our method achieved one of the top results on this open challenge. We demonstrated the generality of our technique by evaluating it on the 2D neurite segmentation challenge dataset where consistently high performance was obtained. We thus expect our method to generalize well to other dense output prediction problems.

  10. [Scanning electron microscopy findings in titanium middle ear prostheses].

    Science.gov (United States)

    Schwager, K

    2000-12-01

    Titanium as a biomaterial in ossicular replacement has widely spread within the last couple of years. 23 prostheses (12 PORPs, partial ossicular replacement prostheses and 11 TORPs total ossicular replacement prostheses) removed during revision surgery were studied using scanning electron microscopy. The average implantation time was 8 (range 3-15) months. The specimens were investigated regarding tissue growth, epithelialization, inflammation and cellular signs of rejection. Only few prostheses were totally covered by connective tissue or epithelium due to technical problems in removing the implant and the covering tissue as one specimen. But this offered the possibility to study the interface at the edges where the tissue was torn off. The connective tissue looked unremarkable. Polygonal squamous epithelium was detected on several implants. Respiratory epithelium with ciliated cells and mucus producing goblet cells was seen in two specimens. In cases of cholesteatoma or protrusion the explanted prostheses showed typical rosette-like formation of hornifying squamous epithelium. According to underlying disease a lymphocytic infiltration could be seen. There were no cellular signs of incompatibility noticed neither macrophages nor foreign body giant cells. From these investigations titanium seems to be a favorable biomaterial for ossicular replacement with good acceptance also in an implantation site showing chronic inflammation.

  11. Cryogenic transmission electron microscopy nanostructural study of shed microparticles.

    Directory of Open Access Journals (Sweden)

    Liron Issman

    Full Text Available Microparticles (MPs are sub-micron membrane vesicles (100-1000 nm shed from normal and pathologic cells due to stimulation or apoptosis. MPs can be found in the peripheral blood circulation of healthy individuals, whereas elevated concentrations are found in pregnancy and in a variety of diseases. Also, MPs participate in physiological processes, e.g., coagulation, inflammation, and angiogenesis. Since their clinical properties are important, we have developed a new methodology based on nano-imaging that provides significant new data on MPs nanostructure, their composition and function. We are among the first to characterize by direct-imaging cryogenic transmitting electron microscopy (cryo-TEM the near-to-native nanostructure of MP systems isolated from different cell types and stimulation procedures. We found that there are no major differences between the MP systems we have studied, as most particles were spherical, with diameters from 200 to 400 nm. However, each MP population is very heterogeneous, showing diverse morphologies. We investigated by cryo-TEM the effects of standard techniques used to isolate and store MPs, and found that either high-g centrifugation of MPs for isolation purposes, or slow freezing to -80 °C for storage introduce morphological artifacts, which can influence MP nanostructure, and thus affect the efficiency of these particles as future diagnostic tools.

  12. Segmentation of electron microscopy images through Gabor texture descriptors

    Science.gov (United States)

    Navarro, Rafael B.; Nestares, Oscar

    1996-03-01

    We have developed a robust method for image segmentation based on a local multiscale texture description. We first apply a set of 4 by 4 complex Gabor filters, plus a low-pass residual (LPR), producing a log-polar sampling of the frequency domain. Contrary to other analysis methods, our Gabor scheme produces a visually complete multipurpose representation of the image, so that it can also be applied to coding, synthesis, etc. Our sixteen texture features consist of local contrast descriptors, obtained by dividing the modulus of the response of the complex Gabor filter by that of the LPR at each location. Contrast descriptors are basically independent of slow variations in intensity, while increasing the robustness and invariance of the representation. Before applying the segmentation algorithm, we equalize the number of samples of the four layers in the resulting pyramid of local contrast descriptors. This method has been applied to segmentation of electron microscopy images, obtaining very good results in this real case, where robustness is a basic requirement, because intensity, textures and other factors are not completely homogeneous.

  13. Davisson-Germer Award Talk: Surface Electron Microscopy with Slow Electrons

    Science.gov (United States)

    Bauer, Ernst

    2005-03-01

    Nearly 80 years ago Davisson and Germer demonstrated the diffraction of slow electrons from surfaces but it is only about 20 years that these electrons have been used for imaging of surfaces and thin films in the Low Energy Electron Microscope (LEEM). Since then several other surface imaging methods with slow electrons have emerged, in particular synchrotron radiation excited photo emission electron microscopy (XPEEM). In LEEM the high intensity of the diffracted slow electrons allows fast image acquisition. Therefore it is tempting to combine it with the other, slower complementary methods. This has been accomplished in the Spectroscopic Photo Emission and Low Energy Electron Microscope (SPELEEM) by adding an energy filter. Today the SPELEEM allows comprehensive structural, chemical, magnetic, electronic characterization of surfaces and thin films by imaging with 10 nm lateral resolution and atomic depth resolution, diffraction and spectroscopy. Recent developments are expected to push the resolution limit into the 1 nm range by aberration correction and the time resolution into and below the picosecond range by pulsed illumination and time-delayed triggered detection. The talk will first describe the general imaging principles and then illustrate with a number of examples the possibilities and limitations of some of the methods, LEEM, Spin-Polarized LEEM (SPLEEM) and X- ray Magnetic Dichroism PEEM (XMCDPEEM). A brief outlook will conclude the presentation.

  14. Improved Visualization of Vertebrate Nuclear Pore Complexes by Field Emission Scanning Electron Microscopy

    National Research Council Canada - National Science Library

    Shaulov, Lihi; Harel, Amnon

    2012-01-01

    Field emission scanning electron microscopy (FESEM) can provide high-resolution three-dimensional surface imaging of many biological structures, including nuclear envelopes and nuclear pore complexes (NPCs...

  15. Integrating electron microscopy into nanoscience and materials engineering programs

    Science.gov (United States)

    Cormia, Robert D.; Oye, Michael M.; Nguyen, Anh; Skiver, David; Shi, Meng; Torres, Yessica

    2014-10-01

    Preparing an effective workforce in high technology is the goal of both academic and industry training, and has been the engine that drives innovation and product development in the United States for over a century. During the last 50 years, technician training has comprised a combination of two-year academic programs, internships and apprentice training, and extensive On-the-Job Training (OJT). Recently, and especially in Silicon Valley, technicians have four-year college degrees, as well as relevant hands-on training. Characterization in general, and microscopy in particular, is an essential tool in process development, manufacturing and QA/QC, and failure analysis. Training for a broad range of skills and practice is challenging, especially for community colleges. Workforce studies (SRI/Boeing) suggest that even four year colleges often do not provide the relevant training and experience in laboratory skills, especially design of experiments and analysis of data. Companies in high-tech further report difficulty in finding skilled labor, especially with industry specific experience. Foothill College, in partnership with UCSC, SJSU, and NASA-Ames, has developed a microscopy training program embedded in a research laboratory, itself a partnership between university and government, providing hands-on experience in advanced instrumentation, experimental design and problem solving, with real-world context from small business innovators, in an environment called `the collaboratory'. The program builds on AFM-SEM training at Foothill, and provides affordable training in FE-SEM and TEM through a cost recovery model. In addition to instrument and engineering training, the collaboratory also supports academic and personal growth through a multiplayer social network of students, faculty, researchers, and innovators.

  16. Transmission Electron Microscopy of Magnetite Plaquettes in Orgueil

    Science.gov (United States)

    Chan, Q. H. S.; Han, J.; Zolensky, M.

    2016-01-01

    Magnetite sometimes takes the form of a plaquette - barrel-shaped stack of magnetite disks - in carbonaceous chondrites (CC) that show evidence of aqueous alteration. The asymmetric nature of the plaquettes caused Pizzarello and Groy to propose magnetite plaquettes as a naturally asymmetric mineral that can indroduce symmetry-breaking in organic molecules. Our previous synchrotron X-ray computed microtomography (SXRCT) and electron backscatter diffraction (EBSD) analyses of the magnetite plaquettes in fifteen CCs indicate that magnetite plaquettes are composed of nearly parallel discs, and the crystallographic orientations of the discs change around a rotational axis normal to the discs surfaces. In order to further investigate the nanostructures of magnetite plaquettes, we made two focused ion beam (FIB) sections of nine magnetite plaquettes from a thin section of CI Orgueil for transmission electron microscope (TEM) analysis. The X-ray spectrum imaging shows that the magnetite discs are purely iron oxide Fe3O4 (42.9 at% Fe and 57.1 at% O), which suggest that the plaquettes are of aqueous origin as it is difficult to form pure magnetite as a nebular condensate. The selected area electron diffraction (SAED) patterns acquired across the plaquettes show that the magnetite discs are single crystals. SEM and EBSD analyses suggest that the planar surfaces of the magnetite discs belong to the {100} planes of the cubic inverse spinel structure, which are supported by our TEM observations. Kerridge et al. suggested that the epitaxial relationship between magnetite plaquette and carbonate determines the magnetite face. However, according to our TEM observation, the association of magnetite with porous networks of phyllosilicate indicates that the epitaxial relationship with carbonate is not essential to the formation of magnetite plaquettes. It was difficult to determine the preferred rotational orientation of the plaquettes due to the symmetry of the cubic structure

  17. The study of vacuolar-type ATPases by single particle electron microscopy1

    National Research Council Canada - National Science Library

    Zhao, Jianhua; Rubinstein, John L

    2014-01-01

    .... Electron microscopy (EM) techniques, especially single particle electron cryomicroscopy (cryo-EM) and negative-stain EM, have provided extensive insight into the structure and function of these protein complexes...

  18. Molecular shape of Lumbricus terrestris erythrocruorin studied by electron microscopy and image analysis

    NARCIS (Netherlands)

    Boekema, Egbert J.; Heel, Marin van

    1989-01-01

    The molecular structure of erythrocruorin (hemoglobin) from Lumbricus terrestris has been studied by electron microscopy of negatively stained particles. Over 1000 molecular projections were selected from a number of electron micrographs and were then classified by multivariate statistical

  19. Structural Analysis of Protein Complexes by Cryo Electron Microscopy.

    Science.gov (United States)

    Costa, Tiago R D; Ignatiou, Athanasios; Orlova, Elena V

    2017-01-01

    Structural studies of biocomplexes using single-particle cryo-electron microscopy (cryo-EM) is now a well-established technique in structural biology and has become competitive with X-ray crystallography. The latest advances in EM enable us to determine structures of protein complexes at 3-5 Å resolution for an extremely broad range of sizes from ~200 kDa up to hundreds of megadaltons (Bartesaghi et al., Science 348(6239):1147-1151, 2051; Bai et al., Nature 525(7568):212-217, 2015; Vinothkumar et al., Nature 515(7525):80-84, 2014; Grigorieff and Harrison, Curr Opin Struct Biol 21(2):265-273, 2011). The majority of biocomplexes comprise a number of different components and are not amenable to crystallisation. Secretion systems are typical examples of such multi-protein complexes, and structural studies of them are extremely challenging. The only feasible approach to revealing their spatial organisation and functional modification is cryo-EM. The development of systems for digital registration of images and algorithms for the fast and efficient processing of recorded images and subsequent analysis facilitated the determination of structures at near-atomic resolution. In this review we will describe sample preparation for cryo-EM, how data are collected by new detectors, and the logistics of image analysis through the basic steps required for reconstructions of both small and large biological complexes and their refinement to nearly atomic resolution. The processing workflow is illustrated using examples of EM analysis of a Type IV Secretion System.

  20. Environmental scanning electron microscopy observation of the ultrastructure of Demodex.

    Science.gov (United States)

    Jing, Xu; Shuling, Guo; Ying, Liu

    2005-12-01

    In this study, numbers of Demodex of hair follicles and sebaceous glands were prepared and the ultrastructure (especially the mouthparts) of Demodex was observed firstly with environmental scanning electron microscopy (ESEM). The most suitable treatment methods and optimal environmental condition for observing the genus samples were found. The samples were washed with detergent and rinsed with distilled water, and then were taken to the specimen stage, on which there was carbon adhesive tape, using special tools. When the temperature was at 5 degrees C and chamber pressure at 5 mbar respectively, the surface of the samples could be fully imaged without covering water or dehydration. The sample surfaces were plump and clear without postmortem changes and charging artifacts. Detailed information about each part of Demodex was observed by ESEM, and clear three-dimensional images were recorded. The mouthparts of D. folliculorum were composed of a complex set of structures, which included a round oral opening, a sharp oral needle, and a special hypostome that looked like a longitudinal spindle in the central position. On the end segment of palpus, there were seven strong palpal claws located on each side of the mouthparts. D. folliculorum had special piercing mouthparts, while the mouthparts of D. brevis were a simpler structure. We could not observe the oral needle of D. brevis, and there were only five pairs of palpal claws on the end segment of palpus. The offensive organs of Demodex resulted in its pathogenic effects. After studying hundreds of Demodex, we identified both female and male species of D. folliculorum, but only females of D. brevis in our sample. (c) 2005 Wiley-Liss, Inc.

  1. EDITORIAL: Electron Microscopy and Analysis Group Conference 2013 (EMAG2013)

    Science.gov (United States)

    Nellist, Pete

    2014-06-01

    It has once again been my pleasure to act as editor for these proceedings, and I must thank all those who have acted as reviewers. I am always struck by the scientific quality of the oral and poster contributions and the vibrant discussions that occur both in the formal sessions and in the exhibition space at EMAG. I am convinced that a crucial part of maintaining that scientific quality is the opportunity that is offered of having a paper fully reviewed by two internationally selected referees and published in the Journal of Physics: Conference Series. For many students, this is the first fully reviewed paper they publish. I hope that, like me, you will be struck by the scientific quality of the 80 papers that follow, and that you will find them interesting and informative. I must also personally thank all the organisers of EMAG2013 for arranging such an excellent meeting. Ian MacLaren, as Chair of the EMAG Group and of the meeting itself, has contributed a foreword to these proceedings describing the meeting in more detail. A particular highlight of the conference was the special symposium in honour of Professor Archie Howie. We all enjoyed a wonderful speech from Archie at the conference dinner, along with some of his electron microscopy-related poetry. I have great pleasure in publishing the conference dinner poems in this proceedings. I hope you will find these proceedings to be an interesting read and an invaluable resource. Pete Nellist Conference committee Conference chair: Dr I MacLaren Programme organiser: Dr C Ducati Proceedings editor: Prof P D Nellist Trade exhibition organiser: C Hockey (CEM Group) Local organisers: Professor E Boyes, Professor P Gai, Dr R Kröger, Dr V Lazarov, Dr P O'Toole, Dr S Tear and Professor J Yuan Advanced school organisers: Dr S Haigh, Dr A Brown Other committee members: Mr K Meade, Mr O Heyning, Dr M Crawford, Mr M Dixon and Dr Z Li

  2. Assessing and ameliorating the influence of the electron beam on carbon nanotube oxidation in environmental transmission electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Koh, Ai Leen, E-mail: alkoh@stanford.edu [Stanford Nano Shared Facilities, Stanford University, Stanford, CA 94305 (United States); Sinclair, Robert [Department of Materials Science and Engineering, Stanford University, Stanford, CA 94305 (United States)

    2017-05-15

    In this work, we examine how the imaging electron beam can induce damage in carbon nanotubes (CNTs) at varying oxygen gas pressures and electron dose rates using environmental transmission electron microscopy (ETEM). Our studies show that there is a threshold cumulative electron dose which brings about damage in CNTs in oxygen – through removal of their graphitic walls – which is dependent on O{sub 2} pressure, with a 4–5 fold decrease in total electron dose per decade increase at a lower pressure range (10{sup −6} to 10{sup −5} mbar) and approximately 1.3 –fold decrease per decade increase at a higher pressure range (10{sup −3} to 10{sup 0} mbar). However, at a given pressure, damage in CNTs was found to occur even at the lowest dose rate utilized, suggesting the absence of a lower limit for the latter parameter. This study provides guidelines on the cumulative dose required to damage nanotubes in the 10{sup −7} mbar to 10{sup 0} mbar pressure regimes, and discusses the role of electron dose rate and total electron dose on beam-induced CNT degradation experiments. - Highlights: • The electron beam ionizes gas molecules in ETEM and affects experimental outcomes. • Beam-induced damage in CNTs occurs at varying O{sub 2} pressures and electron dose rates. • There is a threshold cumulative dose to damage CNTs which depends on O{sub 2} pressure. • At a given pressure, CNT damage occurs even at the electron dose rate utilized.

  3. The New Electron Microscopy: Cells and Molecules in Three Dimensions | Poster

    Science.gov (United States)

    NCI recently announced the launch of the new National Cryo-Electron Microscopy Facility (NCEF) at the Frederick National Laboratory for Cancer Research (FNLCR). The launch comes while cryo-electron microscopy (cryo-EM) is enjoying the spotlight as a newly emerging, rapidly evolving technology with the potential to revolutionize the field of structural biology. Read more...

  4. Structure and Stability of Pt-Y Alloy Particles for Oxygen Reduction Studied by Electron Microscopy

    DEFF Research Database (Denmark)

    Deiana, Davide; Wagner, Jakob Birkedal; Hansen, Thomas Willum

    2015-01-01

    of nanostructured Pt-Y alloy catalysts were studied using transmission electron microscopy techniques. Using elemental X-ray mapping and high-resolution electron microscopy, the specific compositional structure and distribution of the individual nanoparticles was unraveled and the stability assessed. Studying...

  5. A toolkit for the characterization of CCD cameras for transmission electron microscopy

    NARCIS (Netherlands)

    Vulovic, M.; Rieger, B.; Van Vliet, L.J.; Koster, A.J.; Ravelli, R.B.G.

    2009-01-01

    Charge-coupled devices (CCD) are nowadays commonly utilized in transmission electron microscopy (TEM) for applications in life sciences. Direct access to digitized images has revolutionized the use of electron microscopy, sparking developments such as automated collection of tomographic data, focal

  6. Towards correlative super-resolution fluorescence and electron cryo-microscopy

    OpenAIRE

    Wolff, Georg; Hagen, Christoph; Gr?newald, Kay; Kaufmann, Rainer

    2016-01-01

    Correlative light and electron microscopy (CLEM) has become a powerful tool in life sciences. Particularly cryo-CLEM, the combination of fluorescence cryo-microscopy (cryo-FM) permitting for non-invasive specific multi-colour labelling, with electron cryo-microscopy (cryo-EM) providing the undisturbed structural context at a resolution down to the ?ngstrom range, has enabled a broad range of new biological applications. Imaging rare structures or events in crowded environments, such as inside...

  7. Atomic force microscopy and scanning electron microscopy analysis of daily disposable limbal ring contact lenses.

    Science.gov (United States)

    Lorenz, Kathrine Osborn; Kakkassery, Joseph; Boree, Danielle; Pinto, David

    2014-09-01

    Limbal ring (also known as 'circle') contact lenses are becoming increasingly popular, especially in Asian markets because of their eye-enhancing effects. The pigment particles that give the eye-enhancing effects of these lenses can be found on the front or back surface of the contact lens or 'enclosed' within the lens matrix. The purpose of this research was to evaluate the pigment location and surface roughness of seven types of 'circle' contact lenses. Scanning electron microscopic (SEM) analysis was performed using a variable pressure Hitachi S3400N instrument to discern the placement of lens pigments. Atomic force microscopy (Dimension Icon AFM from Bruker Nano) was used to determine the surface roughness of the pigmented regions of the contact lenses. Atomic force microscopic analysis was performed in fluid phase under contact mode using a Sharp Nitride Lever probe (SNL-10) with a spring constant of 0.06 N/m. Root mean square (RMS) roughness values were analysed using a generalised linear mixed model with a log-normal distribution. Least square means and their corresponding 95% confidence intervals were estimated for each brand, location and pigment combination. SEM cross-sectional images at 500× and 2,000× magnification showed pigment on the surface of six of the seven lens types tested. The mean depth of pigment for 1-DAY ACUVUE DEFINE (1DAD) lenses was 8.1 μm below the surface of the lens, while the remaining lens types tested had pigment particles on the front or back surface. Results of the atomic force microscopic analysis indicated that 1DAD lenses had significantly lower root mean square roughness values in the pigmented area of the lens than the other lens types tested. SEM and AFM analysis revealed pigment on the surface of the lens for all types tested with the exception of 1DAD. Further research is required to determine if the difference in pigment location influences on-eye performance. © 2014 The Authors. Clinical and Experimental

  8. Quantitative three-dimensional ice roughness from scanning electron microscopy

    Science.gov (United States)

    Butterfield, Nicholas; Rowe, Penny M.; Stewart, Emily; Roesel, David; Neshyba, Steven

    2017-03-01

    We present a method for inferring surface morphology of ice from scanning electron microscope images. We first develop a novel functional form for the backscattered electron intensity as a function of ice facet orientation; this form is parameterized using smooth ice facets of known orientation. Three-dimensional representations of rough surfaces are retrieved at approximately micrometer resolution using Gauss-Newton inversion within a Bayesian framework. Statistical analysis of the resulting data sets permits characterization of ice surface roughness with a much higher statistical confidence than previously possible. A survey of results in the range -39°C to -29°C shows that characteristics of the roughness (e.g., Weibull parameters) are sensitive not only to the degree of roughening but also to the symmetry of the roughening. These results suggest that roughening characteristics obtained by remote sensing and in situ measurements of atmospheric ice clouds can potentially provide more facet-specific information than has previously been appreciated.

  9. Correlated Cryo-fluorescence and Cryo-electron Microscopy with High Spatial Precision and Improved Sensitivity

    Science.gov (United States)

    Schorb, Martin; Briggs, John A. G.

    2017-01-01

    Performing fluorescence microscopy and electron microscopy on the same sample allows fluorescent signals to be used to identify and locate features of interest for subsequent imaging by electron microscopy. To carry out such correlative microscopy on vitrified samples appropriate for structural cryo-electron microscopy it is necessary to perform fluorescence microscopy at liquid-nitrogen temperatures. Here we describe an adaptation of a cryo-light microscopy stage to permit use of high-numerical aperture objectives. This allows high-sensitivity and high-resolution fluorescence microscopy of vitrified samples. We describe and apply a correlative cryo-fluorescence and cryo-electron microscopy workflow together with a fiducial bead-based image correlation procedure. This procedure allows us to locate fluorescent bacteriophages in cryo-electron microscopy images with an accuracy on the order of 50 nm, based on their fluorescent signal. It will allow the user to precisely and unambiguously identify and locate objects and events for subsequent high-resolution structural study, based on fluorescent signals. PMID:24275379

  10. Correlated cryo-fluorescence and cryo-electron microscopy with high spatial precision and improved sensitivity.

    Science.gov (United States)

    Schorb, Martin; Briggs, John A G

    2014-08-01

    Performing fluorescence microscopy and electron microscopy on the same sample allows fluorescent signals to be used to identify and locate features of interest for subsequent imaging by electron microscopy. To carry out such correlative microscopy on vitrified samples appropriate for structural cryo-electron microscopy it is necessary to perform fluorescence microscopy at liquid-nitrogen temperatures. Here we describe an adaptation of a cryo-light microscopy stage to permit use of high-numerical aperture objectives. This allows high-sensitivity and high-resolution fluorescence microscopy of vitrified samples. We describe and apply a correlative cryo-fluorescence and cryo-electron microscopy workflow together with a fiducial bead-based image correlation procedure. This procedure allows us to locate fluorescent bacteriophages in cryo-electron microscopy images with an accuracy on the order of 50 nm, based on their fluorescent signal. It will allow the user to precisely and unambiguously identify and locate objects and events for subsequent high-resolution structural study, based on fluorescent signals. © 2013 Published by Elsevier B.V.

  11. Assessing strain mapping by electron backscatter diffraction and confocal Raman microscopy using wedge-indented Si

    Energy Technology Data Exchange (ETDEWEB)

    Friedman, Lawrence H.; Vaudin, Mark D.; Stranick, Stephan J.; Stan, Gheorghe; Gerbig, Yvonne B.; Osborn, William; Cook, Robert F., E-mail: robert.cook@nist.gov

    2016-04-15

    The accuracy of electron backscatter diffraction (EBSD) and confocal Raman microscopy (CRM) for small-scale strain mapping are assessed using the multi-axial strain field surrounding a wedge indentation in Si as a test vehicle. The strain field is modeled using finite element analysis (FEA) that is adapted to the near-indentation surface profile measured by atomic force microscopy (AFM). The assessment consists of (1) direct experimental comparisons of strain and deformation and (2) comparisons in which the modeled strain field is used as an intermediate step. Direct experimental methods (1) consist of comparisons of surface elevation and gradient measured by AFM and EBSD and of Raman shifts measured and predicted by CRM and EBSD, respectively. Comparisons that utilize the combined FEA–AFM model (2) consist of predictions of distortion, strain, and rotation for comparison with EBSD measurements and predictions of Raman shift for comparison with CRM measurements. For both EBSD and CRM, convolution of measurements in depth-varying strain fields is considered. The interconnected comparisons suggest that EBSD was able to provide an accurate assessment of the wedge indentation deformation field to within the precision of the measurements, approximately 2×10{sup −4} in strain. CRM was similarly precise, but was limited in accuracy to several times this value. - Highlights: • We map strain by electron backscatter diffraction and confocal Raman microscopy. • The test vehicle is the multi-axial strain field of wedge-indented silicon. • Strain accuracy is assessed by direct experimental intercomparison. • Accuracy is also assessed by atomic force microscopy and finite element analyses. • Electron diffraction measurements are accurate; Raman measurements need refinement.

  12. Morphology of the dentin structure of sloths Bradypus tridactylus: a light and scanning electron microscopy investigation.

    Science.gov (United States)

    Santana, L N S; Barbosa, L V M; Teixeira, F B; Costa, A M P; Fernandes, L M P; Lima, R R

    2013-12-01

    The aim of this study was to describe the dentine morphology of sloths (Bradypus tridactylus). The sloth teeth were removed and prepared for light microscopy (LM) and scanning electron microscopy analyses (SEM). LM revealed two patterns of tubular dentins: an outer with dentinary tubules over the all tooth length and one in the inner part with larger diameter and more spaced tubules, when compared to those present in the outer dentine. These findings were confirmed by SEM, which revealed a tubular pattern in the outer dentine like in humans. The inner dentine displayed pared grouped tubules that were characterized as vascular channels. It can be concluded that this sloth species present two types of dentins: an inner dentin (ortodentin) and an outer dentin characterized as a vascular dentin. This suggests a partial evolutive/adaptive process of this dental tissue, as compared to other mammalian species. © 2013 Blackwell Verlag GmbH.

  13. Low temperature electron microscopy and electron diffraction of the purple membrane of Halobacterium halobium

    Energy Technology Data Exchange (ETDEWEB)

    Hayward, S.B.

    1978-09-01

    The structure of the purple membrane of Halobacterium halobium was studied by high resolution electron microscopy and electron diffraction, primarily at low temperature. The handedness of the purple membrane diffraction pattern with respect to the cell membrane was determined by electron diffraction of purple membranes adsorbed to polylysine. A new method of preparing frozen specimens was used to preserve the high resolution order of the membranes in the electron microscope. High resolution imaging of glucose-embedded purple membranes at room temperature was used to relate the orientation of the diffraction pattern to the absolute orientation of the structure of the bacteriorhodopsin molecule. The purple membrane's critical dose for electron beam-induced damage was measured at room temperature and at -120/sup 0/C, and was found to be approximately five times greater at -120/sup 0/C. Because of this decrease in radiation sensitivity, imaging of the membrane at low temperature should result in an increased signal-to-noise ratio, and thus better statistical definition of the phases of weak reflections. Higher resolution phases may thus be extracted from images than can be determined by imaging at room temperature. To achieve this end, a high resolution, liquid nitrogen-cooled stage was built for the JEOL-100B. Once the appropriate technology for taking low dose images at very high resolution has been developed, this stage will hopefully be used to determine the high resolution structure of the purple membrane.

  14. Observation of the sweating in lipstick by scanning electron microscopy.

    Science.gov (United States)

    Seo, S Y; Lee, I S; Shin, H Y; Choi, K Y; Kang, S H; Ahn, H J

    1999-06-01

    The relationship between the wax matrix in lipstick and sweating has been investigated by observing the change of size and shape of the wax matrix due to sweating by Scanning Electron Microscopy (SEM). For observation by SEM, a lipstick sample was frozen in liquid nitrogen. The oil in the lipstick was then extracted in cold isopropanol (-70 degrees C) for 1-3 days. After the isopropanol was evaporated, the sample was sputtered with gold and examined by SEM. The change of wax matrix underneath the surface from fine, uniform structure to coarse, nonuniform structure resulted from the caking of surrounding wax matrix. The oil underneath the surface migrated to the surface of lipstick with sweating; consequently the wax matrix in that region was rearranged into the coarse matrix. In case of flamed lipstick, sweating was delayed and the wax matrix was much coarser than that of the unflamed one. The larger wax matrix at the surface region was good for including oil. The effect of molding temperature on sweating was also studied. As the molding temperature rose, sweating was greatly reduced and the size of the wax matrix increased. It was found that sweating was influenced by the compatibility of wax and oil. A formula consisting of wax and oil that have good compatibility has a tendency to reduce sweating and increase the size of the wax matrix. When pigments were added to wax and oil, the size of the wax matrix was changed, but in all cases sweating was increased due to the weakening of the binding force between wax and oil. On observing the thick membrane of wax at the surface of lipstick a month after molding it was also found that sweating was influenced by ageing. In conclusion, the structure of the wax matrix at the surface region of lipstick was changed with the process of flaming, molding temperature, compatibility of wax and oil, addition of pigment, and ageing. In most cases, as the size of the wax matrix was increased, sweating was reduced and delayed.

  15. Topographic contrast of ultrathin cryo-sections for correlative super-resolution light and electron microscopy

    Science.gov (United States)

    Mateos, José María; Guhl, Bruno; Doehner, Jana; Barmettler, Gery; Kaech, Andres; Ziegler, Urs

    2016-01-01

    Fluorescence microscopy reveals molecular expression at nanometer resolution but lacks ultrastructural context information. This deficit often hinders a clear interpretation of results. Electron microscopy provides this contextual subcellular detail, but protein identification can often be problematic. Correlative light and electron microscopy produces complimentary information that expands our knowledge of protein expression in cells and tissue. Inherent methodological difficulties are however encountered when combining these two very different microscopy technologies. We present a quick, simple and reproducible method for protein localization by conventional and super-resolution light microscopy combined with platinum shadowing and scanning electron microscopy to obtain topographic contrast from the surface of ultrathin cryo-sections. We demonstrate protein distribution at nuclear pores and at mitochondrial and plasma membranes in the extended topographical landscape of tissue. PMID:27666401

  16. Spatiotemporal Observation of Electron-Impact Dynamics in Photovoltaic Materials Using 4D Electron Microscopy

    KAUST Repository

    Shaheen, Basamat

    2017-05-17

    Understanding light-triggered charge carrier dynamics near photovoltaic-material surfaces and at interfaces has been a key element and one of the major challenges for the development of real-world energy devices. Visualization of such dynamics information can be obtained using the one-of-a-kind methodology of scanning ultrafast electron microscopy (S-UEM). Here, we address the fundamental issue of how the thickness of the absorber layer may significantly affect the charge carrier dynamics on material surfaces. Time-resolved snapshots indicate that the dynamics of charge carriers generated by electron impact in the electron-photon dynamical probing regime is highly sensitive to the thickness of the absorber layer, as demonstrated using CdSe films of different thicknesses as a model system. This finding not only provides the foundation for potential applications of S-UEM to a wide range of devices in the fields of chemical and materials research, but also has impact on the use and interpretation of electron beam-induced current for optimization of photoactive materials in these devices.

  17. Spatiotemporal Observation of Electron-Impact Dynamics in Photovoltaic Materials Using 4D Electron Microscopy.

    Science.gov (United States)

    Shaheen, Basamat S; Sun, Jingya; Yang, Ding-Shyue; Mohammed, Omar F

    2017-06-01

    Understanding light-triggered charge carrier dynamics near photovoltaic-material surfaces and at interfaces has been a key element and one of the major challenges for the development of real-world energy devices. Visualization of such dynamics information can be obtained using the one-of-a-kind methodology of scanning ultrafast electron microscopy (S-UEM). Here, we address the fundamental issue of how the thickness of the absorber layer may significantly affect the charge carrier dynamics on material surfaces. Time-resolved snapshots indicate that the dynamics of charge carriers generated by electron impact in the electron-photon dynamical probing regime is highly sensitive to the thickness of the absorber layer, as demonstrated using CdSe films of different thicknesses as a model system. This finding not only provides the foundation for potential applications of S-UEM to a wide range of devices in the fields of chemical and materials research, but also has impact on the use and interpretation of electron beam-induced current for optimization of photoactive materials in these devices.

  18. Characterization of gold nanoparticle films: Rutherford backscattering spectroscopy, scanning electron microscopy with image analysis, and atomic force microscopy

    Directory of Open Access Journals (Sweden)

    Pia C. Lansåker

    2014-10-01

    Full Text Available Gold nanoparticle films are of interest in several branches of science and technology, and accurate sample characterization is needed but technically demanding. We prepared such films by DC magnetron sputtering and recorded their mass thickness by Rutherford backscattering spectroscopy. The geometric thickness dg—from the substrate to the tops of the nanoparticles—was obtained by scanning electron microscopy (SEM combined with image analysis as well as by atomic force microscopy (AFM. The various techniques yielded an internally consistent characterization of the films. In particular, very similar results for dg were obtained by SEM with image analysis and by AFM.

  19. Simulation study of secondary electron images in scanning ion microscopy

    CERN Document Server

    Ohya, K

    2003-01-01

    The target atomic number, Z sub 2 , dependence of secondary electron yield is simulated by applying a Monte Carlo code for 17 species of metals bombarded by Ga ions and electrons in order to study the contrast difference between scanning ion microscopes (SIM) and scanning electron microscopes (SEM). In addition to the remarkable reversal of the Z sub 2 dependence between the Ga ion and electron bombardment, a fine structure, which is correlated to the density of the conduction band electrons in the metal, is calculated for both. The brightness changes of the secondary electron images in SIM and SEM are simulated using Au and Al surfaces adjacent to each other. The results indicate that the image contrast in SIM is much more sensitive to the material species and is clearer than that for SEM. The origin of the difference between SIM and SEM comes from the difference in the lateral distribution of secondary electrons excited within the escape depth.

  20. Structural characterization of colored human iridal melanosomes by photo emission electron microscopy

    Science.gov (United States)

    Peles, Dana N.; Hong, Lian; Simon, John D.; Hu, Dan-Ning

    2009-02-01

    Ocular uveal melanosomes contain both eumelanin and pheomelanin. The ratio of these two melanins has been discussed in relation to the epidemiological data for skin cancer rates, with increased incidence observed for increased relative concentrations of pheomelanin. Recent studies suggest that a similar trend exists underlying the epidemiology of uveal melanomas. In the present study, the biomolecular organization of human iridal melanosomes from different colored irises were examined to determine if the photoreactivity changes with the altered eumelanin:pheomelanin ratio, and whether such changes can account for epidemiological results. Specifically, photoemission electron microscopy (PEEM), a unique surface-sensitive, direct-imaging technique capable of providing chemical information not obtained by other electron microscopies, was used in combination with Duke University's tunable UV free electron laser (FEL) to determine the surface electrochemical properties of melanosomes from blue and dark brown irides. The results demonstrate that the melanins are organized such that pheomelanin is encased by eumelanin. This "casing model" is consistent with kinetic information available on the early steps of melanogenesis and provides new insights into molecular mechanisms underlying the epidemiology of uveal melanoma.

  1. Identification of magnetic Fe-Ti oxides in marine sediments by electron backscatter diffraction in scanning electron microscopy

    NARCIS (Netherlands)

    Franke, C.; Pennock, G.M.; Drury, M.R.; Engelmann, R.; Lattard, D.; Garming, J.F.L.; Dobeneck, T. von; Dekkers, M.J.

    2007-01-01

    In paleomagnetic and environmental magnetic studies the magnetomineralogical identification is usually based on a set of rock magnetic parameters, complemented by crystallographic and chemical information retrieved from X-ray diffraction (XRD), (electron) microscopy or energy dispersive spectroscopy

  2. Experimental setup for energy-filtered scanning confocal electron microscopy (EFSCEM) in a double aberration-corrected transmission electron microscope

    Energy Technology Data Exchange (ETDEWEB)

    Wang, P; Behan, G; Kirkland, A I; Nellist, P D, E-mail: peng.wang@materials.ox.ac.u [Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH (United Kingdom)

    2010-07-01

    Scanning confocal electron microscopy (SCEM) is a new imaging mode in electron microscopy. Spherical aberration corrected electron microscope instruments fitted with two aberration correctors can be used in this mode which provides improved depth resolution and selectivity compared to optical sectioning in a conventional scanning transmission geometry. In this article, we consider a confocal optical configuration for SCEM using inelastically scattered electrons. We lay out the necessary steps for achieving this new operational mode in a double aberration-corrected instrument with uncorrected chromatic aberration and present preliminary experimental results in such mode.

  3. Microscopy of electronic wave function; Microscopie de fonction d'onde electronique

    Energy Technology Data Exchange (ETDEWEB)

    Harb, M.

    2010-09-15

    This work of thesis aims to visualize, on a position sensitive detector, the spatial oscillations of slow electrons ({approx} meV) emitted by a threshold photoionization in the presence of an external electric field. The interference figure obtained represents the square magnitude of electronic wavefunction. This fundamental work allows us to have access to the electronic dynamics and thus to highlight several quantum mechanisms that occur at the atomic scale (field Coulomb, electron/electron interaction..). Despite the presence an electronic core in Li atom, we have succeeded, experimentally and for the first time, in visualizing the wave function associated with the quasi-discrete Stark states coupled to the ionization continuum. Besides, using simulations of wave packet propagation, based on the 'Split-operator' method, we have conducted a comprehensive study of the H, Li and Cs atoms while revealing the significant effects of the Stark resonances. A very good agreement, on and off resonances, was obtained between simulated and experimental results. In addition, we have developed a generalized analytical model to understand deeply the function of VMI (Velocity-Map Imaging) spectrometer. This model is based on the paraxial approximation; it is based on matrix optics calculation by making an analogy between the electronic trajectory and the light beam. An excellent agreement was obtained between the model predictions and the experimental results. (author)

  4. Electronic structure of carbon nanotube systems measured with scanning tunneling microscopy

    Science.gov (United States)

    Hornbaker, Daniel Jay

    Carbon fullerenes are unusually structured molecules with robust mechanical and electronic properties. Their versatility is astounding; envisioned applications range from field emission displays to impregnated metal composites, battery storage media, and nanoelectronic devices. The combination of simple constituency, diverse behavior, and ease of fabrication makes these materials a cornerstone topic in current research. This thesis details scanning tunneling microscopy (STM) experiments investigating how carbon nanotube fullerenes interact with and couple to their local environment. Scanning tunneling microscopy continues to be a key method for characterizing fullerenes, particularly in regards to their electronic properties. The atomic scale nature of this technique makes it uniquely suited for observing individual molecules and determining correlations between locally measured electronic properties and the particular environment of the molecule. The primary subject of this study is single-wall carbon nanotubes (SWNTs), which were observed under various perturbative influences resulting in measurable changes in the electronic structure. Additionally, fullerene heterostructures formed by the encapsulation of C60 molecules within the hollow interiors of SWNTs were characterized for the first time with STM. These novel macromolecules (dubbed "peapods") demonstrate the potential for custom engineering the properties of fullerene materials. Measurements indicate that the properties of individual nanotubes depend sensitively on local interactions. In particular, pronounced changes in electronic behavior are observed in nanotubes exhibiting mechanical distortion, interacting with extrinsic materials (including other nanotubes), and possessing intrinsic defects in the atomic lattice. In fullerene peapods, while no discernable change in the atomic ordering of the encapsulating nanotubes was evident, the presence of interior C60 molecules has a dramatic effect on the

  5. Scanning Electron Microscopy with Samples in an Electric Field

    Science.gov (United States)

    Frank, Ludĕk; Hovorka, Miloš; Mikmeková, Šárka; Mikmeková, Eliška; Müllerová, Ilona; Pokorná, Zuzana

    2012-01-01

    The high negative bias of a sample in a scanning electron microscope constitutes the “cathode lens” with a strong electric field just above the sample surface. This mode offers a convenient tool for controlling the landing energy of electrons down to units or even fractions of electronvolts with only slight readjustments of the column. Moreover, the field accelerates and collimates the signal electrons to earthed detectors above and below the sample, thereby assuring high collection efficiency and high amplification of the image signal. One important feature is the ability to acquire the complete emission of the backscattered electrons, including those emitted at high angles with respect to the surface normal. The cathode lens aberrations are proportional to the landing energy of electrons so the spot size becomes nearly constant throughout the full energy scale. At low energies and with their complete angular distribution acquired, the backscattered electron images offer enhanced information about crystalline and electronic structures thanks to contrast mechanisms that are otherwise unavailable. Examples from various areas of materials science are presented.

  6. Theoretical study of ferroelectric nanoparticles using phase reconstructed electron microscopy

    DEFF Research Database (Denmark)

    Phatak, C.; Petford-Long, A. K.; Beleggia, Marco

    2014-01-01

    Ferroelectric nanostructures are important for a variety of applications in electronic and electro-optical devices, including nonvolatile memories and thin-film capacitors. These applications involve stability and switching of polarization using external stimuli, such as electric fields. We present...... a theoretical model describing how the shape of a nanoparticle affects its polarization in the absence of screening charges, and quantify the electron-optical phase shift for detecting ferroelectric signals with phase-sensitive techniques in a transmission electron microscope. We provide an example phase shift...

  7. Successful application of Low Voltage Electron Microscopy to practical materials problems

    Energy Technology Data Exchange (ETDEWEB)

    Bell, David C., E-mail: dcb@seas.harvard.edu [School of Engineering and Applied Sciences, Harvard University, Cambridge, MA (United States); Center for Nanoscale Systems, Harvard University, Cambridge, MA (United States); Mankin, Max; Day, Robert W. [Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA (United States); Erdman, Natasha [JEOL USA Inc. Peabody, MA (United States)

    2014-10-15

    Low-voltage High-Resolution Electron Microscopy (LVHREM) has several advantages, including increased cross-sections for inelastic and elastic scattering, increased contrast per electron, decreased delocalization effects and reduced knock-on damage. Imaging at differing voltages has shown advantages for imaging materials that are knock-on damage sensitive. We show experimentally that different materials systems benefit from low voltage high-resolution microscopy. There are advantages for imaging single layer materials such as graphene at below the knock-on threshold; we present an example of imaging a graphene sheet at 40 kV. We have also examined mesoporous silica decorated with Pd nanoparticles and carbon black functionalized with Pd/Pt nanoparticles. In these cases we show that the lower voltage imaging maintains the structure of the surrounding matrix during imaging, whereas aberration correction provides the higher resolution for imaging the nanoparticle lattice. Perhaps surprisingly we show that zeolites damage preferentially by ionization effects (radiolysis). The current literature suggests that below incident energies of 40 kV the damage is mainly radiolitic, whereas at incident energies above 200 kV the knock-on damage and material sputtering will be the dominant effect. Our experimental observations support this conclusion and the effects we have observed at 40 kV are not indicative of knock-on damage. Other nanoscale materials such as thin silicon nanowires also benefit from lower voltage imaging. LVHREM imaging provides an excellent option to avoid beam damage to nanowires; our results suggest that LVHREM is suitable for nanowire-biological composites. Our experimental observations serve as a clear demonstration that even at 40 keV accelerating voltage, LVHREM can be used without inducing beam damage to locate dislocations and other crystalline defects, which may have adverse effects on nanowire device performance. Low voltage operation will likely

  8. Double-shot MeV electron diffraction and microscopy

    Directory of Open Access Journals (Sweden)

    P. Musumeci

    2017-07-01

    Full Text Available In this paper, we study by numerical simulations a time-resolved MeV electron scattering mode where two consecutive electron pulses are used to capture the evolution of a material sample on 10 ps time scales. The two electron pulses are generated by illuminating a photocathode in a radiofrequency photogun by two short laser pulses with adjustable delay. A streak camera/deflecting cavity is used after the sample to project the two electron bunches on two well separated regions of the detector screen. By using sufficiently short pulses, the 2D spatial information from each snapshot can be preserved. This “double-shot” technique enables the efficient capture of irreversible dynamics in both diffraction and imaging modes. In this work, we demonstrate both modes in start-to-end simulations of the UCLA Pegasus MeV microscope column.

  9. Rapid combined light and electron microscopy on large frozen biological samples

    NARCIS (Netherlands)

    Vogels, I. M. C.; Hoeben, K. A.; van Noorden, C. J. F.

    2009-01-01

    P>The use of large unfixed frozen tissue samples (10 x 10 x 5 mm(3)) for combined light microscopy (LM) and electron microscopy (EM) is described. First, cryostat sections are applied for various LM histochemical approaches including in situ hybridization, immunohistochemistry and metabolic mapping

  10. CHROMATIN TEXTURE OF MELANOCYTIC NUCLEI - CORRELATION BETWEEN LIGHT AND ELECTRON-MICROSCOPY

    NARCIS (Netherlands)

    ABMAYR, W; STOLZ, W; KORHERR, S; WILD, W; SCHMOECKEL, C

    1987-01-01

    Cells of a benign pigmented mole and a malignant melanoma were used to compare electron microscopy (EM) and light microscopy (LM) with high-resolution TV-scanning and multivariate analysis methods. Special emphasis was placed on different kinds of chromatin texture features and their discriminating

  11. Microscopic techniques bridging between nanoscale and microscale with an atomically sharpened tip - field ion microscopy/scanning probe microscopy/ scanning electron microscopy.

    Science.gov (United States)

    Tomitori, Masahiko; Sasahara, Akira

    2014-11-01

    Over a hundred years an atomistic point of view has been indispensable to explore fascinating properties of various materials and to develop novel functional materials. High-resolution microscopies, rapidly developed during the period, have taken central roles in promoting materials science and related techniques to observe and analyze the materials. As microscopies with the capability of atom-imaging, field ion microscopy (FIM), scanning tunneling microscopy (STM), atomic force microscopy (AFM) and transmission electron microscopy (TEM) can be cited, which have been highly evaluated as methods to ultimately bring forward the viewpoint of reductionism in materials science. On one hand, there have been difficulties to derive useful and practical information on large (micro) scale unique properties of materials using these excellent microscopies and to directly advance the engineering for practical materials. To make bridges over the gap between an atomic scale and an industrial engineering scale, we have to develop emergence science step-by-step as a discipline having hierarchical structures for future prospects by combining nanoscale and microscale techniques; as promising ways, the combined microscopic instruments covering the scale gap and the extremely sophisticated methods for sample preparation seem to be required. In addition, it is noted that spectroscopic and theoretical methods should implement the emergence science.Fundamentally, the function of microscope is to determine the spatial positions of a finite piece of material, that is, ultimately individual atoms, at an extremely high resolution with a high stability. To define and control the atomic positions, the STM and AFM as scanning probe microscopy (SPM) have successfully demonstrated their power; the technological heart of SPM lies in an atomically sharpened tip, which can be observed by FIM and TEM. For emergence science we would like to set sail using the tip as a base. Meanwhile, it is significant

  12. Multi-color electron microscopy by element-guided identification of cells, organelles and molecules

    NARCIS (Netherlands)

    Scotuzzi, Marijke; Kuipers, Jeroen; Wensveen, Dasha I.; de Boer, Pascal; Hagen, Kees (C. ) W.; Hoogenboom, Jacob P.; Giepmans, Ben N. G.

    2017-01-01

    Cellular complexity is unraveled at nanometer resolution using electron microscopy (EM), but interpretation of macromolecular functionality is hampered by the difficulty in interpreting greyscale images and the unidentified molecular content. We perform large-scale EM on mammalian tissue

  13. Fundamental Technical Elements of Freeze-fracture/Freeze-etch in Biological Electron Microscopy

    Science.gov (United States)

    Freeze-fracture/freeze-etch describes a process whereby specimens, typically biological or nanomaterial in nature, are frozen, fractured, and replicated to generate a carbon/platinum "cast" intended for examination by transmission electron microscopy. Specimens are subjected to u...

  14. A genetically encoded tag for correlated light and electron microscopy of intact cells, tissues, and organisms

    National Research Council Canada - National Science Library

    Shu, Xiaokun; Lev-Ram, Varda; Deerinck, Thomas J; Qi, Yingchuan; Ramko, Ericka B; Davidson, Michael W; Jin, Yishi; Ellisman, Mark H; Tsien, Roger Y

    2011-01-01

    Electron microscopy (EM) achieves the highest spatial resolution in protein localization, but specific protein EM labeling has lacked generally applicable genetically encoded tags for in situ visualization in cells and tissues...

  15. Quantitative detection of gold nanoparticles on individual, unstained cancer cells by Scanning Electron Microscopy

    NARCIS (Netherlands)

    Hartsuiker, Liesbeth; van Es, Peter; Petersen, Wilhelmina; van Leeuwen, Ton; Terstappen, Leonardus Wendelinus Mathias Marie; Otto, Cornelis

    2011-01-01

    Gold nanoparticles are rapidly emerging for use in biomedical applications. Characterization of the interaction and delivery of nanoparticles to cells through microscopy is important. Scanning electron microscopes have the intrinsic resolution to visualize gold nanoparticles on cells. A novel sample

  16. New hardware and workflows for semi-automated correlative cryo-fluorescence and cryo-electron microscopy/tomography

    OpenAIRE

    Schorb, Martin; Gaechter, Leander; Avinoam, Ori; Sieckmann, Frank; Clarke, Mairi; Bebeacua, Cecilia; Bykov, Yury S.; Sonnen, Andreas F.-P.; Lihl, Reinhard; John A G Briggs

    2017-01-01

    Correlative light and electron microscopy allows features of interest defined by fluorescence signals to be located in an electron micrograph of the same sample. Rare dynamic events or specific objects can be identified, targeted and imaged by electron microscopy or tomography. To combine it with structural studies using cryo-electron microscopy or tomography, fluorescence microscopy must be performed while maintaining the specimen vitrified at liquid-nitrogen temperatures and in a dry enviro...

  17. Studying Dynamic Processes of Nano-sized Objects in Liquid using Scanning Transmission Electron Microscopy

    OpenAIRE

    Hermannsd?rfer, Justus; de Jonge, Niels

    2017-01-01

    Samples fully embedded in liquid can be studied at a nanoscale spatial resolution with Scanning Transmission Electron Microscopy (STEM) using a microfluidic chamber assembled in the specimen holder for Transmission Electron Microscopy (TEM) and STEM. The microfluidic system consists of two silicon microchips supporting thin Silicon Nitride (SiN) membrane windows. This article describes the basic steps of sample loading and data acquisition. Most important of all is to ensure that the liquid c...

  18. Combining X-ray and electron-microscopy data to solve crystal structures

    Energy Technology Data Exchange (ETDEWEB)

    Navaza, Jorge, E-mail: jorge.navaza@ibs.fr [Laboratoire de Microscopie Electronique Structurale, Institut de Biologie Structurale Jean-Pierre Ebel, 41 Rue Jules Horowitz, F-38027 Grenoble (France)

    2008-01-01

    Overview and examples of combined use of X-ray and electron-microscopy data. Low-resolution electron-microscopy reconstructions can be used as search models in molecular replacement or may be combined with existing monomeric structures in order to produce multimeric models suitable for molecular replacement. The technique is described in the case of viral and subviral particles as well as in the case of oligomeric proteins.

  19. Transmission electron microscopy artifacts in characterization of the nanomaterial-cell interactions.

    Science.gov (United States)

    Leung, Yu Hang; Guo, Mu Yao; Ma, Angel P Y; Ng, Alan M C; Djurišić, Aleksandra B; Degger, Natalie; Leung, Frederick C C

    2017-07-01

    We investigated transmission electron microscopy artifacts obtained using standard sample preparation protocols applied to the investigation of Escherichia coli cells exposed to common nanomaterials, such as TiO 2 , Ag, ZnO, and MgO. While the common protocols for some nanomaterials result only in known issues of nanomaterial-independent generation of anomalous deposits due to fixation and staining, for others, there are reactions between the nanomaterial and chemicals used for post-fixation or staining. Only in the case of TiO 2 do we observe only the known issues of nanomaterial-independent generation of anomalous deposits due to exceptional chemical stability of this material. For the other three nanomaterials, different artifacts are observed. For each of those, we identify causes of the observed problems and suggest alternative sample preparation protocols to avoid artifacts arising from the sample preparation, which is essential for correct interpretation of the obtained images and drawing correct conclusions on cell-nanomaterial interactions. Finally, we propose modified sample preparation and characterization protocols for comprehensive and conclusive investigations of nanomaterial-cell interactions using electron microscopy and for obtaining clear and unambiguous revelation whether the nanomaterials studied penetrate the cells or accumulate at the cell membranes. In only the case of MgO and ZnO, the unambiguous presence of Zn and Mg could be observed inside the cells.

  20. Versatility of the green microalga cell vacuole function as revealed by analytical transmission electron microscopy.

    Science.gov (United States)

    Shebanova, Anastasia; Ismagulova, Tatiana; Solovchenko, Alexei; Baulina, Olga; Lobakova, Elena; Ivanova, Alexandra; Moiseenko, Andrey; Shaitan, Konstantin; Polshakov, Vladimir; Nedbal, Ladislav; Gorelova, Olga

    2017-05-01

    Vacuole is a multifunctional compartment central to a large number of functions (storage, catabolism, maintenance of the cell homeostasis) in oxygenic phototrophs including microalgae. Still, microalgal cell vacuole is much less studied than that of higher plants although knowledge of the vacuolar structure and function is essential for understanding physiology of nutrition and stress tolerance of microalgae. Here, we combined the advanced analytical and conventional transmission electron microscopy methods to obtain semi-quantitative, spatially resolved at the subcellular level information on elemental composition of the cell vacuoles in several free-living and symbiotic chlorophytes. We obtained a detailed record of the changes in cell and vacuolar ultrastructure in response to environmental stimuli under diverse conditions. We suggested that the vacuolar inclusions could be divided into responsible for storage of phosphorus (mainly in form of polyphosphate) and those accommodating non-protein nitrogen (presumably polyamine) reserves, respectively.The ultrastructural findings, together with the data on elemental composition of different cell compartments, allowed us to speculate on the role of the vacuolar membrane in the biosynthesis and sequestration of polyphosphate. We also describe the ultrastructural evidence of possible involvement of the tonoplast in the membrane lipid turnover and exchange of energy and metabolites between chloroplasts and mitochondria. These processes might play a significant role in acclimation in different stresses including nitrogen starvation and extremely high level of CO2 and might also be of importance for microalgal biotechnology. Advantages and limitations of application of analytical electron microscopy to biosamples such as microalgal cells are discussed.

  1. The examination of calcium ion implanted alumina with energy filtered transmission electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Hunt, E.M.; Hampikian, J.M. [Georgia Inst. of Tech., Atlanta, GA (United States). School of Materials Science and Engineering; Evans, N.D. [Oak Ridge Inst. for Science and Education, TN (United States)

    1997-04-01

    Ion implantation can be used to alter in the optical response of insulators through the formation of embedded nano-sized particles. Single crystal alumina has been implanted at ambient temperature with 50 keV Ca{sup +} to a fluence of 5 {times} 10{sup 16} ions/cm{sup 2}. Ion channeling, Knoop microhardness measurements, and transmission electron microscopy (TEM) indicate that the alumina surface layer was amorphized by the implant. TEM also revealed nano-sized crystals {approx}7--8 nm in diameter. These nanocrystals are randomly oriented, and exhibit a face-centered cubic structure (FCC) with a lattice parameter of 0.409 nm {+-} 0.002 nm. The similarity between this crystallography and that of pure aluminum suggests that they are metallic aluminum nanocrystals with a slightly dilated lattice parameter, possibly due to the incorporation of a small amount of calcium. Energy-filtered transmission electron microscopy (EFTEM) provides an avenue by which to confirm the metallic nature of the aluminum involved in the nanocrystals. EFTEM has confirmed that the aluminum present in the particles is metallic in nature, that the particles are oxygen deficient in comparison with the matrix material and that the particles are deficient in calcium, and therefore not likely to be calcia. The particles thus appear to be FCC Al (possibly alloyed with a few percent Ca) with a lattice parameter of 0.409nm. A similar result was obtained for yttrium ion implantation into alumina.

  2. Microscopy

    Science.gov (United States)

    Patricia A. Moss; Les Groom

    2001-01-01

    Microscopy is the study and interpretation of images produced by a microscope. "Interpretation" is the keyword, because the microscope enables one to see structures that are too small or too close together to be resolved by the unaided eye. (The human eye cannot separate two points or lines that are closer together than 0.1 mm.) it is important to...

  3. Transmission Electron Microscopy Studies of Electron-Selective Titanium Oxide Contacts in Silicon Solar Cells

    KAUST Repository

    Ali, Haider

    2017-08-15

    In this study, the cross-section of electron-selective titanium oxide (TiO2) contacts for n-type crystalline silicon solar cells were investigated by transmission electron microscopy. It was revealed that the excellent cell efficiency of 21.6% obtained on n-type cells, featuring SiO2/TiO2/Al rear contacts and after forming gas annealing (FGA) at 350°C, is due to strong surface passivation of SiO2/TiO2 stack as well as low contact resistivity at the Si/SiO2/TiO2 heterojunction. This can be attributed to the transformation of amorphous TiO2 to a conducting TiO2-x phase. Conversely, the low efficiency (9.8%) obtained on cells featuring an a-Si:H/TiO2/Al rear contact is due to severe degradation of passivation of the a-Si:H upon FGA.

  4. Correlative cryo-fluorescence light microscopy and cryo-electron tomography of Streptomyces.

    Science.gov (United States)

    Koning, Roman I; Celler, Katherine; Willemse, Joost; Bos, Erik; van Wezel, Gilles P; Koster, Abraham J

    2014-01-01

    Light microscopy and electron microscopy are complementary techniques that in a correlative approach enable identification and targeting of fluorescently labeled structures in situ for three-dimensional imaging at nanometer resolution. Correlative imaging allows electron microscopic images to be positioned in a broader temporal and spatial context. We employed cryo-correlative light and electron microscopy (cryo-CLEM), combining cryo-fluorescence light microscopy and cryo-electron tomography, on vitrified Streptomyces bacteria to study cell division. Streptomycetes are mycelial bacteria that grow as long hyphae and reproduce via sporulation. On solid media, Streptomyces subsequently form distinct aerial mycelia where cell division leads to the formation of unigenomic spores which separate and disperse to form new colonies. In liquid media, only vegetative hyphae are present divided by noncell separating crosswalls. Their multicellular life style makes them exciting model systems for the study of bacterial development and cell division. Complex intracellular structures have been visualized with transmission electron microscopy. Here, we describe the methods for cryo-CLEM that we applied for studying Streptomyces. These methods include cell growth, fluorescent labeling, cryo-fixation by vitrification, cryo-light microscopy using a Linkam cryo-stage, image overlay and relocation, cryo-electron tomography using a Titan Krios, and tomographic reconstruction. Additionally, methods for segmentation, volume rendering, and visualization of the correlative data are described. © 2014 Elsevier Inc. All rights reserved.

  5. The theory and practice of high resolution scanning electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Joy, D.C. (Tennessee Univ., Knoxville, TN (USA) Oak Ridge National Lab., TN (USA))

    1990-01-01

    Recent advances in instrumentation have produced the first commercial examples of what can justifiably be called High Resolution Scanning Electron Microscopes. The key components of such instruments are a cold field emission gun, a small-gap immersion probe-forming lens, and a clean dry-pumped vacuum. The performance of these microscopes is characterized by several major features including a spatial resolution, in secondary electron mode on solid specimens, which can exceed 1nm on a routine basis; an incident probe current density of the order of 10{sup 6} amps/cm{sup 2}; and the ability to maintain these levels of performance over an accelerating voltage range of from 1 to 30keV. This combination of high resolution, high probe current, low contamination and flexible electron-optical conditions provides many new opportunitites for the application of the SEM to materials science, physics, and the life sciences. 27 refs., 14 figs.

  6. Center for Electron Microscopy, CEN-DTU; The building

    DEFF Research Database (Denmark)

    Horsewell, Andy

    Center for electron nanoscopy, CEN●DTU; The building Andy Horsewell Technical University of Denmark, DTU Materials Technology, Building 204, 2800 Lyngby ABSTRACT CEN●DTU, having been given[1] the opportunity to create a world-class facility with a unique suite of electron microscopes, is in full...... swing with the construction of a purpose-built building. The microscopes are very special: 2 Titans, both Cs corrected, with monochromators and full analytical capabilities are to achieve spatial resolutions of 0.7Å and spectroscopy resolutions of 0.1eV. One of the Titans is to be equipped...... with an environmental cell, to provide in-situ observations of gas-solid interactions at high temperatures. 2 dual beam FIB-FEGSEMs, both with EDS and one with EBSD will allow 3D image, composition and crystallographic reconstruction at sub-nanometer resolution. Additional electron microscopes, making 7 in all...

  7. In-situ electrochemical transmission electron microscopy for battery research.

    Science.gov (United States)

    Mehdi, B Layla; Gu, Meng; Parent, Lucas R; Xu, Wu; Nasybulin, Eduard N; Chen, Xilin; Unocic, Raymond R; Xu, Pinghong; Welch, David A; Abellan, Patricia; Zhang, Ji-Guang; Liu, Jun; Wang, Chong-Min; Arslan, Ilke; Evans, James; Browning, Nigel D

    2014-04-01

    The recent development of in-situ liquid stages for (scanning) transmission electron microscopes now makes it possible for us to study the details of electrochemical processes under operando conditions. As electrochemical processes are complex, care must be taken to calibrate the system before any in-situ/operando observations. In addition, as the electron beam can cause effects that look similar to electrochemical processes at the electrolyte/electrode interface, an understanding of the role of the electron beam in modifying the operando observations must also be understood. In this paper we describe the design, assembly, and operation of an in-situ electrochemical cell, paying particular attention to the method for controlling and quantifying the experimental parameters. The use of this system is then demonstrated for the lithiation/delithiation of silicon nanowires.

  8. Time-resolved scanning electron microscopy with polarization analysis

    Energy Technology Data Exchange (ETDEWEB)

    Frömter, Robert, E-mail: rfroemte@physik.uni-hamburg.de; Oepen, Hans Peter [Institut für Nanostruktur-und Festkörperphysik, Universität Hamburg, Jungiusstraße 11, 20355 Hamburg (Germany); The Hamburg Centre for Ultrafast Imaging, Luruper Chaussee 149, 22761 Hamburg (Germany); Kloodt, Fabian; Rößler, Stefan; Frauen, Axel; Staeck, Philipp; Cavicchia, Demetrio R. [Institut für Nanostruktur-und Festkörperphysik, Universität Hamburg, Jungiusstraße 11, 20355 Hamburg (Germany); Bocklage, Lars [Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, 22607 Hamburg (Germany); The Hamburg Centre for Ultrafast Imaging, Luruper Chaussee 149, 22761 Hamburg (Germany); Röbisch, Volker; Quandt, Eckhard [Institute for Materials Science, Christian-Albrechts-Universität zu Kiel, 24143 Kiel (Germany)

    2016-04-04

    We demonstrate the feasibility of investigating periodically driven magnetization dynamics in a scanning electron microscope with polarization analysis based on spin-polarized low-energy electron diffraction. With the present setup, analyzing the time structure of the scattering events, we obtain a temporal resolution of 700 ps, which is demonstrated by means of imaging the field-driven 100 MHz gyration of the vortex in a soft-magnetic FeCoSiB square. Owing to the efficient intrinsic timing scheme, high-quality movies, giving two components of the magnetization simultaneously, can be recorded on the time scale of hours.

  9. Scanning transmission electron microscopy: Albert Crewe's vision and beyond.

    Science.gov (United States)

    Krivanek, Ondrej L; Chisholm, Matthew F; Murfitt, Matthew F; Dellby, Niklas

    2012-12-01

    Some four decades were needed to catch up with the vision that Albert Crewe and his group had for the scanning transmission electron microscope (STEM) in the nineteen sixties and seventies: attaining 0.5Å resolution, and identifying single atoms spectroscopically. With these goals now attained, STEM developments are turning toward new directions, such as rapid atomic resolution imaging and exploring atomic bonding and electronic properties of samples at atomic resolution. The accomplishments and the future challenges are reviewed and illustrated with practical examples. Copyright © 2012 Elsevier B.V. All rights reserved.

  10. Kelvin probe microscopy and electronic transport measurements in reduced graphene oxide chemical sensors

    Science.gov (United States)

    Kehayias, Christopher E.; MacNaughton, Samuel; Sonkusale, Sameer; Staii, Cristian

    2013-06-01

    Reduced graphene oxide (RGO) is an electronically hybrid material that displays remarkable chemical sensing properties. Here, we present a quantitative analysis of the chemical gating effects in RGO-based chemical sensors. The gas sensing devices are patterned in a field-effect transistor geometry, by dielectrophoretic assembly of RGO platelets between gold electrodes deposited on SiO2/Si substrates. We show that these sensors display highly selective and reversible responses to the measured analytes, as well as fast response and recovery times (tens of seconds). We use combined electronic transport/Kelvin probe microscopy measurements to quantify the amount of charge transferred to RGO due to chemical doping when the device is exposed to electron-acceptor (acetone) and electron-donor (ammonia) analytes. We demonstrate that this method allows us to obtain high-resolution maps of the surface potential and local charge distribution both before and after chemical doping, to identify local gate-susceptible areas on the RGO surface, and to directly extract the contact resistance between the RGO and the metallic electrodes. The method presented is general, suggesting that these results have important implications for building graphene and other nanomaterial-based chemical sensors.

  11. Micromorphology of epicuticular wax structures of the garden strawberry leaves by electron microscopy: syntopism and polymorphism.

    Science.gov (United States)

    Kim, Ki Woo; Ahn, Jeong Joon; Lee, Joon-Ho

    2009-04-01

    Ultrastructural aspects of leaf epicuticular wax structures were investigated in the garden strawberry Fragariaxananassa by scanning and transmission electron microscopy. Both the adaxial and abaxial surfaces of two cultivars (Maehyang and Red Pearl) were collected and subjected to surface observations and ultrathin sections. The most prominent leaf epicuticular wax structures included membraneous platelets and angular rodlets. Most wax platelets were membraneous, and appeared to protrude from the surface at an acute angle. Angular rodlets were usually bent and had rather distinct facets in the abaxial surface of the two cultivars. Membraneous platelets were predominant on the adaxial surface of Maehyang, whereas the adaxial surface of Red Pearl was characterized by angular rodlets. However, both cultivars possessed angular rodlets on the abaxial surface, simultaneously. The combination of air-drying without vacuum and in-lens imaging of secondary electron signals with a field emission gun could impart the superb resolution at low electron dose with minimal specimen shrinkage. In vertical profiles of the leaf epidermis, epicuticular waxes were observed above the cuticle layer, and measured approximately as 50nm in thickness. The natural epicuticular waxes were seemingly mixtures of electron-dense microfibrils, and heterogeneous in shape on ultrathin sections. Distinct crystal-like strata could be hardly discernable in the wax structures. These results suggest that the garden strawberry has the nature of syntopism within one plant and polymorphism within the same species in the formation and occurrence of leaf epicuticular waxes.

  12. Cryo-electron microscopy and cryo-electron tomography of nanoparticles.

    Science.gov (United States)

    Stewart, Phoebe L

    2017-03-01

    Cryo-transmission electron microscopy (cryo-TEM or cryo-EM) and cryo-electron tomography (cryo-ET) offer robust and powerful ways to visualize nanoparticles. These techniques involve imaging of the sample in a frozen-hydrated state, allowing visualization of nanoparticles essentially as they exist in solution. Cryo-TEM grid preparation can be performed with the sample in aqueous solvents or in various organic and ionic solvents. Two-dimensional (2D) cryo-TEM provides a direct way to visualize the polydispersity within a nanoparticle preparation. Fourier transforms of cryo-TEM images can confirm the structural periodicity within a sample. While measurement of specimen parameters can be performed with 2D TEM images, determination of a three-dimensional (3D) structure often facilitates more spatially accurate quantization. 3D structures can be determined in one of two ways. If the nanoparticle has a homogeneous structure, then 2D projection images of different particles can be averaged using a computational process referred to as single particle reconstruction. Alternatively, if the nanoparticle has a heterogeneous structure, then a structure can be generated by cryo-ET. This involves collecting a tilt-series of 2D projection images for a defined region of the grid, which can be used to generate a 3D tomogram. Occasionally it is advantageous to calculate both a single particle reconstruction, to reveal the regular portions of a nanoparticle structure, and a cryo-electron tomogram, to reveal the irregular features. A sampling of 2D cryo-TEM images and 3D structures are presented for protein based, DNA based, lipid based, and polymer based nanoparticles. WIREs Nanomed Nanobiotechnol 2017, 9:e1417. doi: 10.1002/wnan.1417 For further resources related to this article, please visit the WIREs website. © 2016 Wiley Periodicals, Inc.

  13. Study of Black Sand Particles from Sand Dunes in Badr, Saudi Arabia Using Electron Microscopy

    Directory of Open Access Journals (Sweden)

    Haider Abbas Khwaja

    2015-08-01

    Full Text Available Particulate air pollution is a health concern. This study determines the microscopic make-up of different varieties of sand particles collected at a sand dune site in Badr, Saudi Arabia in 2012. Three categories of sand were studied: black sand, white sand, and volcanic sand. The study used multiple high resolution electron microscopies to study the morphologies, emission source types, size, and elemental composition of the particles, and to evaluate the presence of surface “coatings or contaminants” deposited or transported by the black sand particles. White sand was comprised of natural coarse particles linked to wind-blown releases from crustal surfaces, weathering of igneous/metamorphic rock sources, and volcanic activities. Black sand particles exhibited different morphologies and microstructures (surface roughness compared with the white sand and volcanic sand. Morphological Scanning Electron Microscopy (SEM and Laser Scanning Microscopy (LSM analyses revealed that the black sand contained fine and ultrafine particles (50 to 500 nm ranges and was strongly magnetic, indicating the mineral magnetite or elemental iron. Aqueous extracts of black sands were acidic (pH = 5.0. Fe, C, O, Ti, Si, V, and S dominated the composition of black sand. Results suggest that carbon and other contaminant fine particles were produced by fossil-fuel combustion and industrial emissions in heavily industrialized areas of Haifa and Yanbu, and transported as cloud condensation nuclei to Douf Mountain. The suite of techniques used in this study has yielded an in-depth characterization of sand particles. Such information will be needed in future environmental, toxicological, epidemiological, and source apportionment studies.

  14. In situ Electrical measurements in Transmission Electron Microscopy

    NARCIS (Netherlands)

    Rudneva, M.

    2013-01-01

    In the present thesis the combination of real-time electricalmeasurements on nano-sampleswith simultaneous examination by transmission electron microscope (TEM) is discussed. Application of an electrical current may lead to changes in the samples thus the possibility to correlate such changes with

  15. Advantages of environmental scanning electron microscopy in studies of microorganisms.

    Science.gov (United States)

    Collins, S P; Pope, R K; Scheetz, R W; Ray, R I; Wagner, P A; Little, B J

    1993-08-01

    Microorganisms, including bacteria, fungi, protozoa, and microalgae, are composed predominantly of water which prohibits direct observation in a traditional scanning electron microscope (SEM). Preparation for SEM requires that microorganisms be fixed, frozen or dehydrated, and coated with a conductive film before observation in a high vacuum environment. Sample preparation may mechanically disturb delicate samples, compromise morphological information, and introduce other artifacts. The environmental scanning electron microscope (ESEM) provides a technology for imaging hydrated or dehydrated biological samples with minimal manipulation and without the need for conductive coatings. Sporulating cultures of three fungi, Aspergillus sp., Cunninghamella sp., and Mucor sp., were imaged in the ESEM to assess usefulness of the instrument in the direct observation of delicate, uncoated, biological specimens. Asexual sporophores showed no evidence of conidial displacement or disruption of sporangia. Uncoated algal cells of Euglena gracilis and Spirogyra sp. were examined using the backscatter electron detector (BSE) and the environmental secondary electron detector (ESD) of the ESEM. BSE images had more clearly defined intracellular structures, whereas ESD gave a clearer view of the surface E. gracilis cells fixed with potassium permanganate, Spirogyra sp. stained with Lugol's solution, and Saprolegnia sp. fixed with osmium tetroxide were compared using BSE and ESD to demonstrate that cellular details could be enhanced by the introduction of heavy metals. The effect of cellular water on signal quality was evaluated by comparing hydrated to critical point dried specimens.

  16. Bulk sensitive hard x-ray photoemission electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Patt, M., E-mail: m.patt@fz-juelich.de; Wiemann, C. [Peter Grünberg Institute (PGI-6) and JARA-FIT, Research Center Jülich, D-52425 Jülich (Germany); Weber, N.; Escher, M.; Merkel, M. [Focus GmbH, Neukirchner Str. 2, D-65510 Hünstetten (Germany); Gloskovskii, A.; Drube, W. [DESY Photon Science, Deutsches Elektronen-Synchrotron, D-22603 Hamburg (Germany); Schneider, C. M. [Peter Grünberg Institute (PGI-6) and JARA-FIT, Research Center Jülich, D-52425 Jülich (Germany); Fakultät f. Physik and Center for Nanointegration Duisburg-Essen (CeNIDE), Universität Duisburg-Essen, D-47048 Duisburg (Germany)

    2014-11-15

    Hard x-ray photoelectron spectroscopy (HAXPES) has now matured into a well-established technique as a bulk sensitive probe of the electronic structure due to the larger escape depth of the highly energetic electrons. In order to enable HAXPES studies with high lateral resolution, we have set up a dedicated energy-filtered hard x-ray photoemission electron microscope (HAXPEEM) working with electron kinetic energies up to 10 keV. It is based on the NanoESCA design and also preserves the performance of the instrument in the low and medium energy range. In this way, spectromicroscopy can be performed from threshold to hard x-ray photoemission. The high potential of the HAXPEEM approach for the investigation of buried layers and structures has been shown already on a layered and structured SrTiO{sub 3} sample. Here, we present results of experiments with test structures to elaborate the imaging and spectroscopic performance of the instrument and show the capabilities of the method to image bulk properties. Additionally, we introduce a method to determine the effective attenuation length of photoelectrons in a direct photoemission experiment.

  17. Interaction between single gold atom and the graphene edge: A study via aberration-corrected transmission electron microscopy

    KAUST Repository

    Wang, Hongtao

    2012-01-01

    Interaction between single noble metal atoms and graphene edges has been investigated via aberration-corrected and monochromated transmission electron microscopy. A collective motion of the Au atom and the nearby carbon atoms is observed in transition between energy-favorable configurations. Most trapping and detrapping processes are assisted by the dangling carbon atoms, which are more susceptible to knock-on displacements by electron irradiation. Thermal energy is lower than the activation barriers in transition among different energy-favorable configurations, which suggests electron-beam irradiation can be an efficient way of engineering the graphene edge with metal atoms. © 2012 The Royal Society of Chemistry.

  18. The future is cold: cryo-preparation methods for transmission electron microscopy of cells.

    Science.gov (United States)

    Hurbain, Ilse; Sachse, Martin

    2011-09-01

    Our knowledge of the organization of the cell is linked, to a great extent, to light and electron microscopy. Choosing either photons or electrons for imaging has many consequences on the image obtained, as well as on the experiment required in order to generate the image. One apparent effect on the experimental side is in the sample preparation, which can be quite elaborate for electron microscopy. In recent years, rapid freezing, cryo-preparation and cryo-electron microscopy have been more widely used because they introduce fewer artefacts during preparation when compared with chemical fixation and room temperature processing. In addition, cryo-electron microscopy allows the visualization of the hydrated specimens. In the present review, we give an introduction to the rapid freezing of biological samples and describe the preparation steps. We focus on bulk samples that are too big to be directly viewed under the electron microscope. Furthermore, we discuss the advantages and limitations of freeze substitution and cryo-electron microscopy of vitreous sections and compare their application to the study of bacteria and mammalian cells and to tomography.

  19. Correlative super-resolution fluorescence and electron microscopy using conventional fluorescent proteins in vacuo.

    Science.gov (United States)

    Peddie, Christopher J; Domart, Marie-Charlotte; Snetkov, Xenia; O'Toole, Peter; Larijani, Banafshe; Way, Michael; Cox, Susan; Collinson, Lucy M

    2017-08-01

    Super-resolution light microscopy, correlative light and electron microscopy, and volume electron microscopy are revolutionising the way in which biological samples are examined and understood. Here, we combine these approaches to deliver super-accurate correlation of fluorescent proteins to cellular structures. We show that YFP and GFP have enhanced blinking properties when embedded in acrylic resin and imaged under partial vacuum, enabling in vacuo single molecule localisation microscopy. In conventional section-based correlative microscopy experiments, the specimen must be moved between imaging systems and/or further manipulated for optimal viewing. These steps can introduce undesirable alterations in the specimen, and complicate correlation between imaging modalities. We avoided these issues by using a scanning electron microscope with integrated optical microscope to acquire both localisation and electron microscopy images, which could then be precisely correlated. Collecting data from ultrathin sections also improved the axial resolution and signal-to-noise ratio of the raw localisation microscopy data. Expanding data collection across an array of sections will allow 3-dimensional correlation over unprecedented volumes. The performance of this technique is demonstrated on vaccinia virus (with YFP) and diacylglycerol in cellular membranes (with GFP). Copyright © 2017. Published by Elsevier Inc.

  20. Localization of fluorescently labeled structures in frozen-hydrated samples using integrated light electron microscopy.

    Science.gov (United States)

    Faas, F G A; Bárcena, M; Agronskaia, A V; Gerritsen, H C; Moscicka, K B; Diebolder, C A; van Driel, L F; Limpens, R W A L; Bos, E; Ravelli, R B G; Koning, R I; Koster, A J

    2013-03-01

    Correlative light and electron microscopy is an increasingly popular technique to study complex biological systems at various levels of resolution. Fluorescence microscopy can be employed to scan large areas to localize regions of interest which are then analyzed by electron microscopy to obtain morphological and structural information from a selected field of view at nm-scale resolution. Previously, an integrated approach to room temperature correlative microscopy was described. Combined use of light and electron microscopy within one instrument greatly simplifies sample handling, avoids cumbersome experimental overheads, simplifies navigation between the two modalities, and improves the success rate of image correlation. Here, an integrated approach for correlative microscopy under cryogenic conditions is presented. Its advantages over the room temperature approach include safeguarding the native hydrated state of the biological specimen, preservation of the fluorescence signal without risk of quenching due to heavy atom stains, and reduced photo bleaching. The potential of cryo integrated light and electron microscopy is demonstrated for the detection of viable bacteria, the study of in vitro polymerized microtubules, the localization of mitochondria in mouse embryonic fibroblasts, and for a search into virus-induced intracellular membrane modifications within mammalian cells. Copyright © 2012 Elsevier Inc. All rights reserved.

  1. The importance of transmission electron microscopy analysis of spermatozoa: Diagnostic applications and basic research.

    Science.gov (United States)

    Moretti, Elena; Sutera, Gaetano; Collodel, Giulia

    2016-06-01

    This review is aimed at discussing the role of ultrastructural studies on human spermatozoa and evaluating transmission electron microscopy as a diagnostic tool that can complete andrology protocols. It is clear that morphological sperm defects may explain decreased fertilizing potential and acquire particular value in the field of male infertility. Electron microscopy is the best method to identify systematic or monomorphic and non-systematic or polymorphic sperm defects. The systematic defects are characterized by a particular anomaly that affects the vast majority of spermatozoa in a semen sample, whereas a heterogeneous combination of head and tail defects found in variable percentages are typically non-systematic or polymorphic sperm defects. A correct diagnosis of these specific sperm alterations is important for choosing the male infertility's therapy and for deciding to turn to assisted reproduction techniques. Transmission electron microscopy (TEM) also represents a valuable method to explore the in vitro effects of different compounds (for example drugs with potential spermicidal activity) on the morphology of human spermatozoa. Finally, TEM used in combination with immunohistochemical techniques, integrates structural and functional aspects that provide a wide horizon in the understanding of sperm physiology and pathology. transmission electron microscopy: TEM; World Health Organization: WHO; light microscopy: LM; motile sperm organelle morphology examination: MSOME; intracytoplasmic morphologically selected sperm injection: IMSI; intracytoplasmic sperm injection: ICSI; dysplasia of fibrous sheath: DFS; primary ciliary dyskinesia: PCD; outer dense fibers: ODF; assisted reproduction technologies: ART; scanning electron microscopy: SEM; polyvinylpirrolidone: PVP; tert-butylhydroperoxide: TBHP.

  2. High-precision correlative fluorescence and electron cryo microscopy using two independent alignment markers

    Energy Technology Data Exchange (ETDEWEB)

    Schellenberger, Pascale [Oxford Particle Imaging Centre, Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN (United Kingdom); Kaufmann, Rainer [Oxford Particle Imaging Centre, Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN (United Kingdom); Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU (United Kingdom); Siebert, C. Alistair; Hagen, Christoph [Oxford Particle Imaging Centre, Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN (United Kingdom); Wodrich, Harald [Microbiologie Fondamentale et Pathogénicité, MFP CNRS UMR 5234, University of Bordeaux SEGALEN, 146 rue Leo Seignat, 33076 Bordeaux (France); Grünewald, Kay, E-mail: kay@strubi.ox.ac.uk [Oxford Particle Imaging Centre, Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN (United Kingdom)

    2014-08-01

    Correlative light and electron microscopy (CLEM) is an emerging technique which combines functional information provided by fluorescence microscopy (FM) with the high-resolution structural information of electron microscopy (EM). So far, correlative cryo microscopy of frozen-hydrated samples has not reached better than micrometre range accuracy. Here, a method is presented that enables the correlation between fluorescently tagged proteins and electron cryo tomography (cryoET) data with nanometre range precision. Specifically, thin areas of vitrified whole cells are examined by correlative fluorescence cryo microscopy (cryoFM) and cryoET. Novel aspects of the presented cryoCLEM workflow not only include the implementation of two independent electron dense fluorescent markers to improve the precision of the alignment, but also the ability of obtaining an estimate of the correlation accuracy for each individual object of interest. The correlative workflow from plunge-freezing to cryoET is detailed step-by-step for the example of locating fluorescence-labelled adenovirus particles trafficking inside a cell. - Highlights: • Vitrified mammalian cell were imaged by fluorescence and electron cryo microscopy. • TetraSpeck fluorescence markers were added to correct shifts between cryo fluorescence channels. • FluoSpheres fiducials were used as reference points to assign new coordinates to cryoEM images. • Adenovirus particles were localised with an average correlation precision of 63 nm.

  3. Quantification of interfacial segregation by analytical electron microscopy

    CERN Document Server

    Muellejans, H

    2003-01-01

    The quantification of interfacial segregation by spatial difference and one-dimensional profiling is presented in general where special attention is given to the random and systematic uncertainties. The method is demonstrated for an example of Al-Al sub 2 O sub 3 interfaces in a metal-ceramic composite material investigated by energy-dispersive X-ray spectroscopy and electron energy loss spectroscopy in a dedicated scanning transmission electron microscope. The variation of segregation measured at different interfaces by both methods is within the uncertainties, indicating a constant segregation level and interfacial phase formation. The most important random uncertainty is the counting statistics of the impurity signal whereas the specimen thickness introduces systematic uncertainties (via k factor and effective scan width). The latter could be significantly reduced when the specimen thickness is determined explicitly. (orig.)

  4. A Nanoaquarium for in situ Electron Microscopy in Liquid Media

    CERN Document Server

    Grogan, Joseph M

    2010-01-01

    The understanding of many nanoscale processes occurring in liquids such as colloidal crystal formation, aggregation, nanowire growth, electrochemical deposition, and biological interactions would benefit greatly from real-time, in situ imaging with the nanoscale resolution of transmission electron microscopes (TEMs) and scanning transmission electron microscopes (STEMs). However, these imaging tools cannot readily be used to observe processes occurring in liquid media without addressing two experimental hurdles: sample thickness and sample evaporation in the high vacuum microscope chamber. To address these challenges, we have developed a nano-Hele-Shaw cell, dubbed the nanoaquarium. The device consists of a hermetically-sealed, 100 nm tall, liquid-filled chamber sandwiched between two freestanding, 50 nm thick, silicon nitride membranes. Embedded electrodes are integrated into the device. This fluid dynamics video features particle motion and aggregation during in situ STEM of nanoparticles suspended in liqui...

  5. Image simulations of kinked vortices for transmission electron microscopy

    DEFF Research Database (Denmark)

    Beleggia, Marco; Pozzi, G.; Tonomura, A.

    2010-01-01

    We present an improved model of kinked vortices in high-Tc superconductors suitable for the interpretation of Fresnel or holographic observations carried out with a transmission electron microscope. A kinked vortex is composed of two displaced half-vortices, perpendicular to the film plane......, connected by a horizontal flux-line in the plane, resembling a connecting Josephson vortex (JV) segment. Such structures may arise when a magnetic field is applied almost in the plane, and the line tension of the fluxon breaks down under its influence. The existence of kinked vortices was hinted in earlier...... observations of high-Tc superconducting films, where the Fresnel contrast associated with some vortices showed a dumbbell like appearance. Here, we show that under suitable conditions the JV segment may reveal itself in Fresnel imaging or holographic phase mapping in a transmission electron microscope....

  6. Astigmatic intensity equation for electron microscopy based phase retrieval.

    Science.gov (United States)

    Petersen, Tim C; Keast, Vicki J

    2007-08-01

    Phase retrieval, in principle, can be performed in a transmission electron microscope (TEM) using arbitrary aberrations of electron waves; provided that the aberrations are well-characterised and known. For example, the transport of intensity equation (TIE) can be used to infer the phase from a through-focus series of images. In this work an "astigmatic intensity equation" (AIE) is considered, which relates phase gradients to intensity variations caused by TEM objective lens focus and astigmatism variations. Within the paraxial approximation, it is shown that an exact solution of the AIE for the phase can be obtained using efficient Fourier transform methods. Experimental requirements for using the AIE are the measurement of a through-focus derivative and another intensity derivative, which is taken with respect to objective lens astigmatism variation. Two quasi-experimental investigations are conducted to test the validity of the solution.

  7. Nuclear uptake of ultrasmall gold-doxorubicin conjugates imaged by fluorescence lifetime imaging microscopy (FLIM) and electron microscopy.

    Science.gov (United States)

    Zhang, Xuan; Shastry, Sathvik; Bradforth, Stephen E; Nadeau, Jay L

    2015-01-07

    Fluorescence lifetime imaging microscopy (FLIM) has been used to image free and encapsulated doxorubicin (Dox) uptake into cells, since interaction of Dox with DNA leads to a characteristic lifetime change. However, none of the reported Dox conjugates were able to enter cell nuclei. In this work, we use FLIM to show nuclear uptake of 2.7 nm mean diameter Au nanoparticles conjugated to Dox. The pattern of labelling differed substantially from what was seen with free Dox, with slower nuclear entry and stronger cytoplasmic labelling at all time points. As the cells died, the pattern of labelling changed further as intracellular structures disintegrated, consistent with association of Au-Dox to membranes. The patterns of Au distribution and intracellular structure changes were confirmed using electron microscopy, and indicate different mechanisms of cytotoxicity with stable Au-Dox conjugates compared to Dox alone. Such conjugates are promising tools for overcoming resistance in Dox-resistant cancers.

  8. Atomic force microscopy and scanning electron microscopy analysis of daily disposable limbal ring contact lenses

    OpenAIRE

    Lorenz, Kathrine Osborn; Kakkassery, Joseph; Boree, Danielle; Pinto, David

    2014-01-01

    Background Limbal ring (also known as ‘circle’) contact lenses are becoming increasingly popular, especially in Asian markets because of their eye-enhancing effects. The pigment particles that give the eye-enhancing effects of these lenses can be found on the front or back surface of the contact lens or ‘enclosed’ within the lens matrix. The purpose of this research was to evaluate the pigment location and surface roughness of seven types of ‘circle’ contact lenses. Methods Scanning electron ...

  9. Towards a correlative approach for characterising single virus particles by transmission electron microscopy and nanoscale Raman spectroscopy.

    Science.gov (United States)

    Hermelink, A; Naumann, D; Piesker, J; Lasch, P; Laue, M; Hermann, P

    2017-04-10

    The morphology and structure of biological nanoparticles, such as viruses, can be efficiently analysed by transmission electron microscopy (TEM). To chemically characterise such nanoparticles in heterogeneous samples at the single particle level, we suggest tip-enhanced Raman spectroscopy (TERS) as a correlative method. Here we describe a TERS-compatible staining procedure for TEM which involves sample pre-scanning by TEM imaging, nanoparticle relocalisation by atomic force microscopy (AFM) followed by spectroscopic characterization of the virus nanoparticles using TERS. First successful correlative measurements are demonstrated on tobacco mosaic virus particles deposited on silicon-based TEM sample supports. In addition, the advantages and problems of this methodology are discussed.

  10. Electron beam fabrication and characterization of high- resolution magnetic force microscopy tips

    NARCIS (Netherlands)

    Ruhrig, M.; Rührig, M.; Porthun, S.; Porthun, S.; Lodder, J.C.; Mc vitie, S.; Heyderman, L.J.; Johnston, A.B.; Chapman, J.N.

    1996-01-01

    The stray field, magnetic microstructure, and switching behavior of high‐resolution electron beam fabricated thin film tips for magnetic force microscopy (MFM) are investigated with different imaging modes in a transmission electron microscope (TEM). As the tiny smooth carbon needles covered with a

  11. Field-emission scanning electron microscopy of the internal cellular organization of fungi

    NARCIS (Netherlands)

    Muller, W.H.; Aelst, van A.C.; Humbel, B.M.; Krift, van der T.P.; Boekhout, T.

    2000-01-01

    Internal viewing of the cellular organization of hyphae by scanning electron microscopy is an alternative to observing sectioned fungal material with a transmission electron microscope. To study cytoplasmic organelles in the hyphal cells of fungi by SEM, colonies were chemically fixed with

  12. Direct observations of the MOF (UiO-66) structure by transmission electron microscopy

    KAUST Repository

    Zhu, Liangkui

    2013-01-01

    As a demonstration of ab initio structure characterizations of nano metal organic framework (MOF) crystals by high resolution transmission electron microscopy (HRTEM) and electron diffraction tomography methods, a Zr-MOF (UiO-66) structure was determined and further confirmed by Rietveld refinements of powder X-ray diffraction. HRTEM gave direct imaging of the channels. © 2013 The Royal Society of Chemistry.

  13. Imaging of organelles by electron microscopy reveals protein-protein interactions in mitochondria and chloroplasts

    NARCIS (Netherlands)

    Dudkina, Natalya V.; Kouril, Roman; Bultema, Jelle B.; Boekema, Egbert J.

    2010-01-01

    Ongoing progress in electron microscopy (EM) offers now an opening to visualize cells at the nanoscale by cryo-electron tomography (ET). Large protein complexes can be resolved at near-atomic resolution by single particle averaging. Some examples from mitochondria and chloroplasts illustrate the

  14. Scanning Electron Microscopy (SEM) Procedure for HE Powders on a LEO 438VP System

    Energy Technology Data Exchange (ETDEWEB)

    Zaka, Fowzia [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). Energetic Materials Center

    2016-03-08

    This method describes the characterization of HE powders by Scanning Electron Microscopy (SEM). HE particles are dispersed onto an aluminum standard SEM specimen mount. Electron micrographs are collected at various magnifications (150 to 10,000 X) depending on HE particle size.

  15. Scanning Electron Microscopy (SEM) Procedure for HE Powders on a LEO 438VP System

    Energy Technology Data Exchange (ETDEWEB)

    Zaka, Fowzia [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). Energetic Materials Center

    2016-03-21

    This method describes the characterization of HE powders by Scanning Electron Microscopy (SEM). HE particles are dispersed onto an aluminum standard SEM specimen mount. Electron micrographs are collected at various magnifications (150 to 10,000 X) depending on HE particle size.

  16. U-10Mo Sample Preparation and Examination using Optical and Scanning Electron Microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Prabhakaran, Ramprashad [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Joshi, Vineet V. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Rhodes, Mark A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Schemer-Kohrn, Alan L. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Guzman, Anthony D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Lavender, Curt A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2016-03-30

    The purpose of this document is to provide guidelines to prepare specimens of uranium alloyed with 10 weight percent molybdenum (U-10Mo) for optical metallography and scanning electron microscopy. This document also provides instructions to set up an optical microscope and a scanning electron microscope to analyze U-10Mo specimens and to obtain the required information.

  17. U-10Mo Sample Preparation and Examination using Optical and Scanning Electron Microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Prabhakaran, Ramprashad [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Joshi, Vineet V. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Rhodes, Mark A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Schemer-Kohrn, Alan L. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Guzman, Anthony D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Lavender, Curt A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2016-10-01

    The purpose of this document is to provide guidelines to prepare specimens of uranium alloyed with 10 weight percent molybdenum (U-10Mo) for optical metallography and scanning electron microscopy. This document also provides instructions to set up an optical microscope and a scanning electron microscope to analyze U-10Mo specimens and to obtain the required information.

  18. Anisotropic Shape Changes of Silica Nanoparticles Induced in Liquid with Scanning Transmission Electron Microscopy

    NARCIS (Netherlands)

    Zecevic, J.; Hermannsdorfer, Justus; Schuh, Tobias; de Jong, Krijn P.; de Jonge, Niels

    2017-01-01

    Liquid-phase transmission electron microscopy (TEM) is used for in-situ imaging of nanoscale processes taking place in liquid, such as the evolution of nanoparticles during synthesis or structural changes of nanomaterials in liquid environment. Here, it is shown that the focused electron beam of

  19. Visualization of micromorphology of leaf epicuticular waxes of the rubber tree Ficus elastica by electron microscopy.

    Science.gov (United States)

    Kim, Ki Woo

    2008-10-01

    Ultrastructural aspects of leaf epicuticular waxes were investigated in Ficus elastica by scanning and transmission electron microscopy. Glossy leaves of the rubber tree were collected and subjected to different regimes of specimen preparation for surface observations. F. elastica leaves were hypostomatic and stomata were surrounded with a cuticular thickening that formed a rim. The most prominent epicuticular wax structures of F. elastica leaves included granules and platelets. Without fixation and metal coating, epicuticular wax structures could be discerned on the leaf surface by low-vacuum (ca. 7 Pa) scanning electron microscopy. In terms of delineation and retention of the structures, the combination of vapor fixation by glutaraldehyde and osmium tetroxide with subsequent gold coating provided the most satisfactory results, as evidenced by high resolution and sharp protrusions of epicuticular waxes. However, erosion of epicuticular wax edges was noted in the immersion fixed leaves, showing less elongated platelets, less distinct wax edges, and granule cracking. These results suggest that the vapor fixation procedure for demonstrating three-dimensional epicuticular wax structures would facilitate characterization of diverse types of waxes. Instances were noted where epicuticular waxes grew over neighboring epidermal ridges and occluded stomata. In cross sections, epicuticular waxes were observed above the cuticle proper and ranged approximately from 100 nm to 500 nm in thickness. The native leaf epicuticular waxes had many layers of different electron density that were oriented parallel to each other and parallel or perpendicular to the cuticle surface, implying strata of crystal growth. Such retention of native epicuticular wax structures could be achieved through the use of acrylic resin treated with less harsh dehydrants and mild heat polymerization, alleviating wax extraction during specimen preparations.

  20. Electron microscopy of hydrocarbon production in parthenium argentatum (guayule)

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, Thomas E. [Univ. of California, Berkeley, CA (United States)

    1977-11-01

    The electron microscope was used to study the biological processes involved in hydrocarbon production. The little desert shrub Guayule (Parthenium argentatum) was selected for study. This shrub can produce hydrocarbons (rubber) in concentrations up to 1/4 of its dry weight. It grows on semi-arid land and has been extensively studied. The potential of Guayule is described in detail. Results of an investigation into the morphology of Guayule at the electron microscope level are given. Experiments, which would allow the biosynthesis of hydrocarbon in Guayule to be followed, were designed. In order to do this, knowledge of the biochemistry of rubber formation was used to select a tracer, mevalonic acid. Mevalonic acid is the precursor of all the terpenoids, a large class of hydrocarbons which includes rubber. It was found that when high enough concentrations of mevalonic acid are administered to seedling Guayule plants, build-ups of metabolized products are found within the chloroplasts of the seedlings. Also, tritium labeled mevalonic acid was used as a precursor, and its metabolic progress was followed by using the technique of electron microscope autoradiography. The results of these experiments also implicated chloroplasts of the Guayule plant in hydrocarbon production. The final task was the development of a system to produce three-dimensional stereo reconstructions of organelles suspected of involvement in hydrocarbon biosynthesis in Guayule. The techniques are designed to reconstruct an object from serial sections of that object. The techniques use stereo imaging both to abstract information for computer processing, and also in the computer produced reconstruction.

  1. Cryogenic Electron Microscopy Studies: Structure and Formation of Self-assembled Nanostructures in Solution

    Science.gov (United States)

    Lee, Han Seung

    morphology prepared with flash nanoprecipitation method. Cryo-TEM also visualized drug release kinetics of the silicate PTX prodrugs, suggesting diffusion or degradation release mechanisms. Lastly, formulation of nanoemulsion through phase change emulsification of water/alkane/alkylphenolethoxylate non-ionic surfactant microemulsions is investigated. The amount of cosurfactant determined phase behavior characteristics of microemulsions. The initial structure of the microemulsions determined resulting nanoemulsions. The oil-in-water microemulsions became an exfoliating lamellar intermediate structure during quenching and dilution. The process produced small, simple, and uniform nanoemulsions. Complimentary electron microscopy techniques such as cryo-TEM, cryogenic scanning electron microscopy, and freeze-fracture electron microscopy elucidated microstructural development at each stage. This result enables to control both intra- and inter-molecular forces that govern structure and properties relationship, therefore, to correlate the optimization and the performance of engineered liquid systems within the specified constraints.

  2. Electron microscopy analysis of structural changes within white etching areas

    DEFF Research Database (Denmark)

    Diederichs, Annika Martina; Schwedt, A.; Mayer, J.

    2016-01-01

    In the present work, crack networks with white etching areas (WEAs) in cross-sections of bearings were investigated by a complementary use of SEM and TEM with the focus on the use of orientation contrast imaging and electron backscatter diffraction (EBSD). Orientation contrast imaging was used...... observed within WEAs. Using EBSD analysis, evidence was obtained that WEA formation and accompanying crack growth are without relation microstructural features. In addition, an inhomogeneous chemical structure of WEA as a result of carbide dissolution is revealed by analytical investigations....

  3. [Scanning electron microscopy of heat-damaged bone tissue].

    Science.gov (United States)

    Harsanyl, L

    1977-02-01

    Parts of diaphyses of bones were exposed to high temperature of 200-1300 degrees C. Damage to the bone tissue caused by the heat was investigated. The scanning electron microscopic picture seems to be characteristic of the temperature applied. When the bones heated to the high temperature of 700 degrees C characteristic changes appear on the periostal surface, higher temperatura on the other hand causes damage to the compact bone tissue and can be observed on the fracture-surface. Author stresses the importance of this technique in the legal medicine and anthropology.

  4. Identification of Charcot-Leyden crystals by electron microscopy.

    Science.gov (United States)

    Carson, H J; Buschmann, R J; Weisz-Carrington, P; Choi, Y S

    1992-01-01

    Observations of the ultrastructure of Charcot-Leyden crystals are sporadic in the literature. These crystals appear occasionally in clinical materials, however, and may pose diagnostic dilemmas if not correctly identified. Two cases in which unusual crystallike structures were seen on electron micrographs of specimens were evaluated for diagnostic purposes. These structures were tentatively identified as Charcot-Leyden crystals and subsequently were confirmed as such by immunoperoxidase labeling. The cases are reported together with a review of the ultrastructure, histology, immunology, and natural history of Charcot-Leyden crystals.

  5. Anterior lens epithelium in cataract patients with retinitis pigmentosa - scanning and transmission electron microscopy study.

    Science.gov (United States)

    Andjelic, Sofija; Drašlar, Kazimir; Hvala, Anastazija; Hawlina, Marko

    2017-05-01

    In retinitis pigmentosa (RP) patients, relatively minor lens opacity in central part of posterior pole of the lens may cause disproportionate functional symptoms requiring cataract operation. To investigate the possible structural reasons for this opacity development, we studied the structure of the lens epithelium of patients with RP. The anterior lens capsule (aLC: basement membrane and associated lens epithelial cells, LECs) was obtained from cataract surgery and prepared for scanning and transmission electron microscopy (SEM and TEM). Both SEM and TEM show a number of abnormal features in the anterior lens epithelium of cataract patients with RP. The abnormalities appear mainly as holes, thinning and degradation of the epithelium, with the dimensions from cataractous lens. We suggest that the lens epithelium has a role in the development of the cataract in patients with RP. © 2016 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

  6. Crucial steps in the structure determination of a coronavirus spike glycoprotein using cryo-electron microscopy.

    Science.gov (United States)

    Walls, Alexandra; Tortorici, M Alejandra; Bosch, Berend-Jan; Frenz, Brandon; Rottier, Peter J M; DiMaio, Frank; Rey, Felix A; Veesler, David

    2017-01-01

    The tremendous pandemic potential of coronaviruses was demonstrated twice in the last 15 years by two global outbreaks of deadly pneumonia. Entry of coronaviruses into cells is mediated by the transmembrane spike glycoprotein S, which forms a trimer carrying receptor-binding and membrane fusion functions. Despite their biomedical importance, coronavirus S glycoproteins have proven difficult targets for structural characterization, precluding high-resolution studies of the biologically relevant trimer. Recent technological developments in single particle cryo-electron microscopy allowed us to determine the first structure of a coronavirus S glycoprotein trimer which provided a framework to understand the mechanisms of viral entry and suggested potential inhibition strategies for this family of viruses. Here, we describe the key factors that enabled this breakthrough. © 2016 The Protein Society.

  7. Use of scanning electron microscopy to monitor nanofibre/cell interaction in digestive epithelial cells.

    Science.gov (United States)

    Millaku, Agron; Drobne, Damjana; Torkar, Matjaz; Novak, Sara; Remškar, Maja; Pipan-Tkalec, Živa

    2013-09-15

    We provide data obtained by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) on the interaction of ingested tungsten nanofibers with epithelial cells of the digestive tubes of a test organism Porcellio scaber. Conventional toxicity endpoints including feeding behaviour, weight loss and mortality were also measured in each investigated animal. No toxicity was detected in any of exposed animals after 14 days of feeding on tungsten nanofiber dosed food, but when nanofibers enter the digestive system they can react with epithelial cells of the digestive tubes, becoming physically inserted into the cells. In this way, nanofibers can injure the epithelial cells of digestive gland tubes when they are ingested with food. Our SEM data suggest that peristaltic forces may have an important role, not predicted by in vitro experiments, in the interactions of nanomaterials with digestive intestinal cells. Copyright © 2013 Elsevier B.V. All rights reserved.

  8. Chemical Reactions of Molecules Promoted and Simultaneously Imaged by the Electron Beam in Transmission Electron Microscopy.

    Science.gov (United States)

    Skowron, Stephen T; Chamberlain, Thomas W; Biskupek, Johannes; Kaiser, Ute; Besley, Elena; Khlobystov, Andrei N

    2017-08-15

    The main objective of this Account is to assess the challenges of transmission electron microscopy (TEM) of molecules, based on over 15 years of our work in this field, and to outline the opportunities in studying chemical reactions under the electron beam (e-beam). During TEM imaging of an individual molecule adsorbed on an atomically thin substrate, such as graphene or a carbon nanotube, the e-beam transfers kinetic energy to atoms of the molecule, displacing them from equilibrium positions. Impact of the e-beam triggers bond dissociation and various chemical reactions which can be imaged concurrently with their activation by the e-beam and can be presented as stop-frame movies. This experimental approach, which we term ChemTEM, harnesses energy transferred from the e-beam to the molecule via direct interactions with the atomic nuclei, enabling accurate predictions of bond dissociation events and control of the type and rate of chemical reactions. Elemental composition and structure of the reactant molecules as well as the operating conditions of TEM (particularly the energy of the e-beam) determine the product formed in ChemTEM processes, while the e-beam dose rate controls the reaction rate. Because the e-beam of TEM acts simultaneously as a source of energy for the reaction and as an imaging tool monitoring the same reaction, ChemTEM reveals atomic-level chemical information, such as pathways of reactions imaged for individual molecules, step-by-step and in real time; structures of illusive reaction intermediates; and direct comparison of catalytic activity of different transition metals filmed with atomic resolution. Chemical transformations in ChemTEM often lead to previously unforeseen products, demonstrating the potential of this method to become not only an analytical tool for studying reactions, but also a powerful instrument for discovery of materials that can be synthesized on preparative scale.

  9. In-situ reduction of promoted cobalt oxide supported on alumina by environmental transmission electron microscopy

    DEFF Research Database (Denmark)

    Dehghan, Roya; Hansen, Thomas Willum; Wagner, Jakob Birkedal

    2011-01-01

    Reduction of 12wt.%Co/0.5wt.%Re/α-Al2O3 Fischer–Tropsch catalyst has been studied in-situ in an environmental transmission electron microscope. Reduction of Co3O4 to metallic cobalt was observed dynamically at 360 °C under 3.4 mbar H2. Structural and morphological changes were observed by high...... resolution transmission electron microscopy and scanning transmission electron microscopy imaging. The cobalt particles were mainly face centred cubic while some hexagonal close packed particles were also found. Reoxidation of the sample upon cooling to room temperature, still under flowing H2, underlines...

  10. Nanomaterial datasets to advance tomography in scanning transmission electron microscopy

    Science.gov (United States)

    Levin, Barnaby D. A.; Padgett, Elliot; Chen, Chien-Chun; Scott, M. C.; Xu, Rui; Theis, Wolfgang; Jiang, Yi; Yang, Yongsoo; Ophus, Colin; Zhang, Haitao; Ha, Don-Hyung; Wang, Deli; Yu, Yingchao; Abruña, Hector D.; Robinson, Richard D.; Ercius, Peter; Kourkoutis, Lena F.; Miao, Jianwei; Muller, David A.; Hovden, Robert

    2016-06-01

    Electron tomography in materials science has flourished with the demand to characterize nanoscale materials in three dimensions (3D). Access to experimental data is vital for developing and validating reconstruction methods that improve resolution and reduce radiation dose requirements. This work presents five high-quality scanning transmission electron microscope (STEM) tomography datasets in order to address the critical need for open access data in this field. The datasets represent the current limits of experimental technique, are of high quality, and contain materials with structural complexity. Included are tomographic series of a hyperbranched Co2P nanocrystal, platinum nanoparticles on a carbon nanofibre imaged over the complete 180° tilt range, a platinum nanoparticle and a tungsten needle both imaged at atomic resolution by equal slope tomography, and a through-focal tilt series of PtCu nanoparticles. A volumetric reconstruction from every dataset is provided for comparison and development of post-processing and visualization techniques. Researchers interested in creating novel data processing and reconstruction algorithms will now have access to state of the art experimental test data.

  11. A method of correlative light and electron microscopy for yeast cells.

    Science.gov (United States)

    Asakawa, Haruhiko; Hiraoka, Yasushi; Haraguchi, Tokuko

    2014-06-01

    Correlative light and electron microscopy (CLEM) is a method of imaging in which the same specimen is observed by both light microscopy and electron microscopy. Specifically, CLEM compares images obtained by light and electron microscopy and makes a correlation between them. After the advent of fluorescent proteins, CLEM was extended by combining electron microscopy with fluorescence microscopy to enable molecular-specific imaging of subcellular structures with a resolution at the nanometer level. This method is a powerful tool that is used to determine the localization of specific molecules of interest in the context of subcellular structures. Knowledge of the localization of target proteins coupled with the functions of the structures to which they are localized yields valuable information about the molecular functions of these proteins. However, this method has been mostly applied to adherent cells due to technical difficulties in immobilizing non-adherent target cells, such as yeasts, during sample preparation. We have developed a method of CLEM applicable to yeast cells. In this report, we detail this method and present its extension to Live CLEM. The Live CLEM method enabled us to link the dynamic properties of molecules of interest to cellular ultrastructures in the yeast cell. Since yeasts are premier organisms in molecular genetics, combining CLEM with yeast genetics promises to provide important new findings for understanding the molecular basis of the function of cellular structures. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. Visualization of carrier dynamics in p(n)-type GaAs by scanning ultrafast electron microscopy.

    Science.gov (United States)

    Cho, Jongweon; Hwang, Taek Yong; Zewail, Ahmed H

    2014-02-11

    Four-dimensional scanning ultrafast electron microscopy is used to investigate doping- and carrier-concentration-dependent ultrafast carrier dynamics of the in situ cleaved single-crystalline GaAs(110) substrates. We observed marked changes in the measured time-resolved secondary electrons depending on the induced alterations in the electronic structure. The enhancement of secondary electrons at positive times, when the electron pulse follows the optical pulse, is primarily due to an energy gain involving the photoexcited charge carriers that are transiently populated in the conduction band and further promoted by the electron pulse, consistent with a band structure that is dependent on chemical doping and carrier concentration. When electrons undergo sufficient energy loss on their journey to the surface, dark contrast becomes dominant in the image. At negative times, however, when the electron pulse precedes the optical pulse (electron impact), the dynamical behavior of carriers manifests itself in a dark contrast which indicates the suppression of secondary electrons upon the arrival of the optical pulse. In this case, the loss of energy of material's electrons is by collisions with the excited carriers. These results for carrier dynamics in GaAs(110) suggest strong carrier-carrier scatterings which are mirrored in the energy of material's secondary electrons during their migration to the surface. The approach presented here provides a fundamental understanding of materials probed by four-dimensional scanning ultrafast electron microscopy, and offers possibilities for use of this imaging technique in the study of ultrafast charge carrier dynamics in heterogeneously patterned micro- and nanostructured material surfaces and interfaces.

  13. Identification of sandstone core damage using scanning electron microscopy

    Science.gov (United States)

    Ismail, Abdul Razak; Jaafar, Mohd Zaidi; Sulaiman, Wan Rosli Wan; Ismail, Issham; Shiunn, Ng Yinn

    2017-12-01

    Particles and fluids invasion into the pore spaces causes serious damage to the formation, resulting reduction in petroleum production. In order to prevent permeability damage for a well effectively, the damage mechanisms should be identified. In this study, water-based drilling fluid was compared to oil-based drilling fluids based on microscopic observation. The cores were damaged by several drilling fluid systems. Scanning electron microscope (SEM) was used to observe the damage mechanism caused by the drilling fluids. Results showed that the ester based drilling fluid system caused the most serious damage followed by synthetic oil based system and KCI-polymer system. Fine solids and filtrate migration and emulsion blockage are believed to be the major mechanisms controlling the changes in flow properties for the sandstone samples.

  14. In-Situ Transmission Electron Microscopy on Operating Electrochemical Cells

    DEFF Research Database (Denmark)

    Gualandris, Fabrizio; Simonsen, Søren Bredmose; Mogensen, Mogens Bjerg

    with animage corrector and a differential pumping system.A symmetric cell was prepared by depositing a cell consisting of three thin films on a strontium titanate (STO)single crystal substrate by pulsed laser deposition (PLD). Lanthanum strontium cobaltite La0.6Sr0.4CoO3-δ (LSC)was chosen as electrode....... Comparing the two figures, the cell exposed tooxygen showed structural changes in the LSC thin film in comparison with the sample heated in vacuum. Thesechanges refer to the formation of grains as is confirmed by electron diffraction patterns....... have been often used for ex-situpost mortem characterization of SOFCs and SOECs [2,3]. However, in order to get fundamental insight of themicrostructural development of SOFC/SOEC during operation conditions in-situ studies are necessary [4]. Thedevelopment of advanced TEM chips and holders makes...

  15. Survey of high voltage electron microscopy worldwide in 1998.

    Energy Technology Data Exchange (ETDEWEB)

    Allen, C. W.

    1998-03-05

    High voltage TEMs were introduced commercially thirty years ago, with the installations of 500 kV Hitachi instruments at the Universities of Nagoya and Tokyo. Since that time 53 commercial instruments, having maximum accelerating potentials of 0.5-3.5 MV, will have been delivered by the end of 1998. Table 1 summarizes the sites and some information regarding those HVEMS which are available in 1998. This corrects, updates and expands an earlier report of this sort [2]. There have been three commercial HVEM manufacturers: AEI (UK), Hitachi and JEOL (Japan). The proportion of the total number of HVEMS produced by each manufacturer is similar to that reflected in Table 1: AEI and Kratos/AEI (12), Hitachi (20) and JEOL (21). The term Kratos/AEI refers to instruments delivered after the takeover of AEI by Grates in the late 1970's. In Table 1 only maximum accelerating potentials are listed, which is generally also the design value for which the resolution for imaging was optimized. It is important to realize that in many applications, especially those studying irradiation effects, much lower voltages may be employed somewhat routinely to minimize atom displacements by the incident electron beam during analysis. These minimum values range from 100 kV for the AEI and Kratos/AEI instruments to typically 400 kV for the current generation of atomic resolution instruments, the latter being well above the thresholds for displacement in light elements such as Al and Si and for displacement of anions in many ceramic materials such as the high Tc superconductors, for example. An additional potential problem is electron-induced sputtering and differential sputtering (unequal sputtering rates in multicomponent materials), especially when accurate elemental microanalysis is being attempted. These same issues may arise for intermediate voltage TEMs as well, of course.

  16. Magnetic dynamics studied by high-resolution electron spectroscopy and time-resolved electron microscopy

    Science.gov (United States)

    Jayaraman, Rajeswari

    Future information technology requires an increased magnetically encoded data density and novel electromagnetic modes of data transfer. While to date magnetic properties are observed and characterized mostly statically, the need emerges to monitor and capture their fast dynamics. In this talk, I will focus on the spin dynamics i.e. spin wave excitations and the dynamics of a new topological distribution of spins termed ``skyrmions''. Wave packets of spin waves offer the unique capability to transport a quantum bit, the spin, without the transport of charge or mass. Here, large wave-vector spin waves are of particular interest as they admit spin localization within a few nanometers. By using our recently developed electron energy loss spectrometer, we could study such spin waves in ultrathin films with an unprecedented energy resolution of 4 meV. By virtue of the finite penetration depth of low energy electrons, spin waves localized at interfaces between a substrate and a thin capping layer can be been studied yielding information about the exchange coupling between atoms at the interface. The quantization of spin waves with wave vectors perpendicular to the film gives rise to standing modes to which EELS has likewise access. Such studies when carried out as function of the film thickness again yield information on the layer dependence of the exchange coupling. Magnetic skyrmions are promising candidates as information carriers in logic or storage devices. Currently, little is known about the influence of disorder, defects, or external stimuli on the spatial distribution and temporal evolution of the skyrmion lattice. In this talk, I will describe the dynamical role of disorder in a large and flat thin film of Cu2OSeO3, exhibiting a skyrmion phase in an insulating material. We image up to 70,000 skyrmions by means of cryo-Lorentz Transmission Electron Microscopy as a function of the applied magnetic field. In the skyrmion phase, dislocations are shown to cause the

  17. Visualizing a Complete Siphoviridae Member by Single-Particle Electron Microscopy: the Structure of Lactococcal Phage TP901-1

    Science.gov (United States)

    Bebeacua, Cecilia; Lai, Livia; Vegge, Christina Skovgaard; Brøndsted, Lone; van Heel, Marin

    2013-01-01

    Tailed phages are genome delivery machines exhibiting unequaled efficiency acquired over more than 3 billion years of evolution. Siphophages from the P335 and 936 families infect the Gram-positive bacterium Lactococcus lactis using receptor-binding proteins anchored to the host adsorption apparatus (baseplate). Crystallographic and electron microscopy (EM) studies have shed light on the distinct adsorption strategies used by phages of these two families, suggesting that they might also rely on different infection mechanisms. Here, we report electron microscopy reconstructions of the whole phage TP901-1 (P335 species) and propose a composite EM model of this gigantic molecular machine. Our results suggest conservation of structural proteins among tailed phages and add to the growing body of evidence pointing to a common evolutionary origin for these virions. Finally, we propose that host adsorption apparatus architectures have evolved in correlation with the nature of the receptors used during infection. PMID:23135714

  18. PREFACE: Electron Microscopy and Analysis Group Conference (EMAG2015)

    Science.gov (United States)

    MacLaren, Ian

    2015-10-01

    2015 marked a new venture for the EMAG group of the Institute of Physics in that the conference was held in conjunction with the MMC2015 conference at the wonderful Manchester Central conference centre. As anyone who was there would be able to confirm, this went exceptionally well and was a really vibrant and top quality conference. The oral sessions were filled with good talks, the poster sessions were very lively, and there was a good balance between oral sessions with a specifically "EMAG" identity, and the integration into a larger conference with the ability to switch between up to six parallel sessions covering physical sciences, techniques, and life sciences. The large conference also attracted a wide range of exhibitors, and this is essential for the ongoing success of all of our work, in a field that is very dependent on continued technical innovation and on collaborations between academic researchers and commercial developers of microscopes, holders, detectors, spectrometers, sample preparation equipment, and software, among other things. As has long been the case at EMAG, all oral and poster presenters were invited to submit papers for consideration for the proceedings. As ever, these papers were independently reviewed by other conference attendees, with the aim of continuing the long tradition of the EMAG proceedings being a top quality, peer-reviewed publication, worthy of reference in future years. Whilst I recognise that not all presenters were able to submit papers to the proceedings (for instance due to the need not to prejudice publication in some other journals, or due to avoiding duplicate publication of data), we are gratified that our presenters submitted as many papers as they did. The 41 papers included provide an interesting snapshot of many of the areas covered in the conference presentations, including functional materials, coatings, 3D microscopy, FIB and SEM, nanomaterials, magnetic and structural materials, advances in EM techniques

  19. Scanning probe microscopy and field emission schemes for studying electron emission from polycrystalline diamond

    OpenAIRE

    Chubenko, Oksana; Baturin, Stanislav S.; Baryshev, Sergey V.

    2016-01-01

    The letter introduces a diagram that rationalizes tunneling atomic force microscopy (TUNA) observations of electron emission from polycrystalline diamonds as described in recent publications. The direct observations of electron emission from grain boundary sites by TUNA could indeed be evidence of electrons originating from grain boundaries under external electric fields. At the same time, from the diagram it follows that TUNA and field emission schemes are complimentary rather than equivalen...

  20. Free-living spirochetes from Cape Cod microbial mats detected by electron microscopy

    Science.gov (United States)

    Teal, T. H.; Chapman, M.; Guillemette, T.; Margulis, L.

    1996-01-01

    Spirochetes from microbial mats and anaerobic mud samples collected in salt marshes were studied by light microscopy, whole mount and thin section transmission electron microscopy. Enriched in cellobiose-rifampin medium, selective for Spirochaeta bajacaliforniensis, seven distinguishable spirochete morphotypes were observed. Their diameters ranged from 0.17 micron to > 0.45 micron. Six of these morphotypes came from southwest Cape Cod, Massachusetts: five from Microcoleus-dominated mat samples collected at Sippewissett salt marsh and one from anoxic mud collected at School Street salt marsh (on the east side of Eel Pond). The seventh morphotype was enriched from anoxic mud sampled from the north central Cape Cod, at the Sandy Neck salt marsh. Five of these morphotypes are similar or identical to previously described spirochetes (Leptospira, Spirochaeta halophila, Spirochaeta bajacaliforniensis, Spirosymplokos deltaeiberi and Treponema), whereas the other two have unique features that suggest they have not been previously described. One of the morphotypes resembles Spirosymplokos deltaeiberi (the largest free-living spirochete described), in its large variable diameter (0.4-3.0 microns), cytoplasmic granules, and spherical (round) bodies with composite structure. This resemblance permits its tentative identification as a Sippewissett strain of Spirosymplokos deltaeiberi. Microbial mats samples collected in sterile Petri dishes and stored dry for more than four years yielded many organisms upon rewetting, including small unidentified spirochetes in at least 4 out of 100 enrichments.

  1. Simultaneous Bright-Field and Dark-Field Scanning Transmission Electron Microscopy in Scanning Electron Microscopy: A New Approach for Analyzing Polymer System Morphology

    Science.gov (United States)

    Patel, Binay S.

    Scanning transmission electron microscopy in scanning electron microscopy (STEM-IN-SEM) is a convenient technique for polymer characterization. Utilizing the lower accelerating voltages, larger field of view and, exclusion of post-specimen projection lens in an SEM; STEM-IN-SEM has shown results comparable to transmission electron microscopy (TEM) observation of polymer morphology. Various specimen-holder geometries and detector arrangements have been used for bright field (BF) STEM-IN-SEM imaging. To further the characterization potential of STEM-IN-SEM a new specimen holder has been developed to facilitate simultaneous BF and dark field (DF) STEM-IN-SEM imaging. A new specimen holder and a new microscope configuration were designed for this new imaging technique. BF and DF signals were maximized for optimal STEM-IN-SEM imaging. BF signal intensities were found to be twice as large as DF signal intensities. BF and DF STEM-IN-SEM imaging spatial resolutions are limited to 1.8 nm and approximately 5 nm, respectively. Simultaneous BF & DF STEM-IN-SEM imaging is applicable to both industrial and academic research environments. Examples of commodity and engineering polymer morphology characterization are provided. Results are comparable to TEM observation and may serve as a suitable precursor to STEM characterization of polymer systems. Finally, future developments of various accessories for this technique are discussed.

  2. Improved Hilbert phase contrast for transmission electron microscopy.

    Science.gov (United States)

    Koeck, Philip J B

    2015-07-01

    Hilbert phase contrast has been recognized as a means of recording high resolution images with high contrast using a transmission electron microscope. This imaging mode could be used to image typical phase objects such as unstained biological molecules or cryo sections of biological tissue. According to the original proposal by (Danev et al., 2002) the Hilbert phase plate applies a phase shift of π to approximately half the focal plane (for example the right half excluding the central beam) and an image is recorded at Gaussian focus. After correction for the inbuilt asymmetry of differential phase contrast this image will have an almost perfect contrast transfer function (close to 1) from the lowest spatial frequency up to a maximum resolution determined by the wave length and spherical aberration of the microscope. In this paper I present theory and simulations showing that this maximum spatial frequency can be increased considerably almost without loss of contrast by using a Hilbert phase plate of half the thickness, leading to a phase shift of π/2, and recording images at Scherzer defocus. The maximum resolution can be improved even more by imaging at extended Scherzer defocus, though at the cost of contrast loss at lower spatial frequencies. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Scanning electron microscopy investigations regarding Adonis vernalis L. flower morphology

    Directory of Open Access Journals (Sweden)

    Irina Neta GOSTIN

    2009-11-01

    Full Text Available The floral morphology of Adonis vernalis L. was observed with a scanning electron microscope (SEM. The investigations are important to clarify some taxonomical problems and also could provide useful diagnostic elements for the identification of this medicinal plant in powdered materials. All floral organs are initiated spirally and centripetally and develop centripetally. The petals (8-12 are shorter than the sepals (5-6 in early developmental stages. The petals are disposed on spiral (with 3-4 whorls. The stamens (numerous are unbranched and reach maturity centripetally; they are free of the perianth. The anther walls consisting of a single layer epidermis in the anther wall surrounding the sporagenous tissue, one row of endothecium, two to four rows of middle layer and one row of tapetum layer. In the anther walls, the tapetal cells, by glandular type, persist later in ontogenesis. Pollen grains are tricolpate with echinate surface. The gynoecium is multiple, apocarpous with distinct carpels. The carpels are ascidiate from the beginning. At the base of each carpel, numerousness short, unicellular, trichomes are present. The stigma differentiates as two crests along the ventral slit of the ovary. Each carpel contains a single ovule inside the ovary cavity. The mature ovule is anatropous, with two integuments. It is almost parallel to the funicle.

  4. In situ Transmission Electron Microscopy of catalyst sintering

    DEFF Research Database (Denmark)

    DeLaRiva, Andrew T.; Hansen, Thomas Willum; Challa, Sivakumar R.

    2013-01-01

    along with our recent in situ TEM studies on the sintering of Ni/MgAl2O4 catalysts. These results suggest that the rapid loss of catalyst activity in the earliest stages of catalyst sintering could result from Ostwald ripening rather than through particle migration and coalescence. The smallest...... of Ostwald ripening as well as atomistic Monte Carlo simulations are both in good agreement with these experimental observations, predicting a steep loss in catalyst activity at short times on stream. The in situ studies show the importance of direct observations to deduce mechanisms and show the important...

  5. Direct observation of defect structure in protein crystals by atomic force and transmission electron microscopy.

    OpenAIRE

    Devaud, G; Furcinitti, P S; Fleming, J.C.; Lyon, M K; Douglas, K

    1992-01-01

    We have examined the structure of S-layers isolated from Sulfolobus acidocaldarius using atomic force microscopy (AFM) and transmission electron microscopy (TEM). From the AFM images, we were able to directly observe individual dimers of the crystal, defects in the crystal structure, and twin boundaries. We have identified two types of boundaries, one defined by a mirror plane and the other by a glide plane. This work shows that twin boundaries are highly structured regions that are directly ...

  6. Short unligated sticky ends enable the observation of circularised DNA by atomic force and electron microscopies.

    OpenAIRE

    Révet, B; Fourcade, A

    1998-01-01

    A comparative study of the stabilisation of DNA sticky ends by divalent cations was carried out by atomic force microscopy (AFM), electron microscopy and agarose gel electrophoresis. At room temperature, molecules bearing such extremities are immediately oligomerised or circularised by addition of Mg2+or Ca2+. This phenomenon, more clearly detected by AFM, requires the presence of uranyl salt, which stabilises the structures induced by Mg2+or Ca2+. DNA fragments were obtained by restriction e...

  7. Quantifying Chemical and Electrochemical Reactions in Liquids by in situ Electron Microscopy

    DEFF Research Database (Denmark)

    Canepa, Silvia

    of electrochemical deposition of copper (Cu) by electrochemical liquid scanning electron microscopy (EC-SEM) was done in order to direct observe the formation of dendritic structures. Finally the shape evolution from solid to hollow structures through galvanic replacement reactions were observed for different silver...... (Ag) nanotemplates (cube, rod, nanowires) and gold chloride solution. Results demonstrated that by combining in situ LTEM and ECSEM microscopy with quantitative analysis and systematic studies, meaningful information about the controllable synthesis of metal NPs is achievable....

  8. Candida albicans morphologies revealed by scanning electron microscopy analysis

    Directory of Open Access Journals (Sweden)

    M. Staniszewska

    2013-09-01

    Full Text Available Scanning electron microscope (SEM observations were used to analyze particular morphologies of Candida albicans clinical isolate (strain 82 and mutants defective in hyphae-promoting genes EFG1 (strain HLC52 and/ or CPH1 (strains HLC54 and Can16. Transcription factors Efg1 and Cph1 play role in regulating filamentation and adhesion of C. albicans' morphologies. Comparative analysis of such mutants and clinical isolate showed that Efg1 is required for human serum-induced cell growth and morphological switching. In the study, distinct differences between ultrastructural patterns of clinical strain's and null mutants' morphologies were observed (spherical vs tube-like blastoconidia, or solid and fragile constricted septa vs only the latter observed in strains with EFG1 deleted. In addition, wild type strain displayed smooth colonies of cells in comparison to mutants which exhibited wrinkled phenotype. It was observed that blastoconidia of clinical strain exhibited either polarly or randomly located budding. Contrariwise, morphotypes of mutants showed either multiple polar budding or a centrally located single bud scar (mother-daughter cell junction distinguishing tube-like yeast/ pseudohyphal growth (the length-to-width ratios larger than 1.5. In their planktonic form of growth, blastoconidia of clinical bloodstream isolate formed constitutively true hyphae under undiluted human serum inducing conditions. It was found that true hyphae are essential elements for developing structural integrity of conglomerate, as mutants displaying defects in their flocculation and conglomerate-forming abilities in serum. While filamentation is an important virulence trait in C. albicans the true hyphae are the morphologies which may be expected to play a role in bloodstream infections.

  9. Carbon contamination in scanning transmission electron microscopy and its impact on phase-plate applications.

    Science.gov (United States)

    Hettler, Simon; Dries, Manuel; Hermann, Peter; Obermair, Martin; Gerthsen, Dagmar; Malac, Marek

    2017-05-01

    We analyze electron-beam induced carbon contamination in a transmission electron microscope. The study is performed on thin films potentially suitable as phase plates for phase-contrast transmission electron microscopy. Electron energy-loss spectroscopy and phase-plate imaging is utilized to analyze the contamination. The deposited contamination layer is identified as a graphitic carbon layer which is not prone to electrostatic charging whereas a non-conductive underlying substrate charges. Several methods that inhibit contamination are evaluated and the impact of carbon contamination on phase-plate imaging is discussed. The findings are in general interesting for scanning transmission electron microscopy applications. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

  10. Interactive stereo electron microscopy enhanced with virtual reality

    Energy Technology Data Exchange (ETDEWEB)

    Bethel, E.Wes; Bastacky, S.Jacob; Schwartz, Kenneth S.

    2001-12-17

    An analytical system is presented that is used to take measurements of objects perceived in stereo image pairs obtained from a scanning electron microscope (SEM). Our system operates by presenting a single stereo view that contains stereo image data obtained from the SEM, along with geometric representations of two types of virtual measurement instruments, a ''protractor'' and a ''caliper''. The measurements obtained from this system are an integral part of a medical study evaluating surfactant, a liquid coating the inner surface of the lung which makes possible the process of breathing. Measurements of the curvature and contact angle of submicron diameter droplets of a fluorocarbon deposited on the surface of airways are performed in order to determine surface tension of the air/liquid interface. This approach has been extended to a microscopic level from the techniques of traditional surface science by measuring submicrometer rather than millimeter diameter droplets, as well as the lengths and curvature of cilia responsible for movement of the surfactant, the airway's protective liquid blanket. An earlier implementation of this approach for taking angle measurements from objects perceived in stereo image pairs using a virtual protractor is extended in this paper to include distance measurements and to use a unified view model. The system is built around a unified view model that is derived from microscope-specific parameters, such as focal length, visible area and magnification. The unified view model ensures that the underlying view models and resultant binocular parallax cues are consistent between synthetic and acquired imagery. When the view models are consistent, it is possible to take measurements of features that are not constrained to lie within the projection plane. The system is first calibrated using non-clinical data of known size and resolution. Using the SEM, stereo image pairs of grids and spheres of

  11. High-contrast en bloc staining of neuronal tissue for field emission scanning electron microscopy.

    Science.gov (United States)

    Tapia, Juan Carlos; Kasthuri, Narayanan; Hayworth, Kenneth J; Schalek, Richard; Lichtman, Jeff W; Smith, Stephen J; Buchanan, JoAnn

    2012-01-12

    Conventional heavy metal poststaining methods on thin sections lend contrast but often cause contamination. To avoid this problem, we tested several en bloc staining techniques to contrast tissue in serial sections mounted on solid substrates for examination by field emission scanning electron microscopy (FESEM). Because FESEM section imaging requires that specimens have higher contrast and greater electrical conductivity than transmission electron microscopy (TEM) samples, our technique uses osmium impregnation (OTO) to make the samples conductive while heavily staining membranes for segmentation studies. Combining this step with other classic heavy metal en bloc stains, including uranyl acetate (UA), lead aspartate, copper sulfate and lead citrate, produced clean, highly contrasted TEM and scanning electron microscopy (SEM) samples of insect, fish and mammalian nervous systems. This protocol takes 7-15 d to prepare resin-embedded tissue, cut sections and produce serial section images.

  12. A compilation of cold cases using scanning electron microscopy at the University of Rhode Island

    Science.gov (United States)

    Platek, Michael J.; Gregory, Otto J.

    2015-10-01

    Scanning electron microscopy combined with microchemical analysis has evolved into one of the most widely used instruments in forensic science today. In particular, the environmental scanning electron microscope (SEM) in conjunction with energy dispersive spectroscopy (EDS), has created unique opportunities in forensic science in regard to the examination of trace evidence; i.e. the examination of evidence without altering the evidence with conductive coatings, thereby enabling criminalists to solve cases that were previously considered unsolvable. Two cold cases were solved at URI using a JEOL 5900 LV SEM in conjunction with EDS. A cold case murder and a cold missing person case will be presented from the viewpoint of the microscopist and will include sample preparation, as well as image and chemical analysis of the trace evidence using electron microscopy and optical microscopy.

  13. Correlated fluorescence microscopy and cryo-electron tomography of virus-infected or transfected mammalian cells.

    Science.gov (United States)

    Hampton, Cheri M; Strauss, Joshua D; Ke, Zunlong; Dillard, Rebecca S; Hammonds, Jason E; Alonas, Eric; Desai, Tanay M; Marin, Mariana; Storms, Rachel E; Leon, Fredrick; Melikyan, Gregory B; Santangelo, Philip J; Spearman, Paul W; Wright, Elizabeth R

    2017-01-01

    Correlative light and electron microscopy (CLEM) combines spatiotemporal information from fluorescence light microscopy (fLM) with high-resolution structural data from cryo-electron tomography (cryo-ET). These technologies provide opportunities to bridge knowledge gaps between cell and structural biology. Here we describe our protocol for correlated cryo-fLM, cryo-electron microscopy (cryo-EM), and cryo-ET (i.e., cryo-CLEM) of virus-infected or transfected mammalian cells. Mammalian-derived cells are cultured on EM substrates, using optimized conditions that ensure that the cells are spread thinly across the substrate and are not physically disrupted. The cells are then screened by fLM and vitrified before acquisition of cryo-fLM and cryo-ET images, which is followed by data processing. A complete session from grid preparation through data collection and processing takes 5-15 d for an individual experienced in cryo-EM.

  14. Cryo-electron microscopy of an extremely halophilic microbe: technical aspects.

    Science.gov (United States)

    Bollschweiler, Daniel; Schaffer, Miroslava; Lawrence, C Martin; Engelhardt, Harald

    2017-03-01

    Most halophilic Archaea of the class Halobacteriaceae depend on the presence of several molar sodium chloride for growth and cell integrity. This poses problems for structural studies, particularly for electron microscopy, where the high salt concentration results in diminished contrast. Since cryo-electron microscopy of intact cells provides new insights into the cellular and molecular organization under close-to-live conditions, we evaluated strategies and conditions to make halophilic microbes available for investigations in situ. Halobacterium salinarum, the test organism for this study, usually grows at 4.3 M NaCl. Adaptation to lower concentrations and subsequent NaCl reduction via dialysis led to still vital cells at 3 M salt. A comprehensive evaluation of vitrification parameters, thinning of frozen cells by focused-ion-beam micromachining, and cryo-electron microscopy revealed that structural studies under high salt conditions are possible in situ.

  15. The importance of scanning electron microscopy (sem in taxonomy and morphology of Chironomidae (Diptera

    Directory of Open Access Journals (Sweden)

    Andrzej Kownacki

    2015-07-01

    Full Text Available The paper reports on the value of scanning electron microscopy (SEM in the taxonomy and morphology of Chironomidae. This method has been relatively rarely used in Chironomidae studies. Our studies suggest that the SEM method provides a lot of new information. For example, the plastron plate of the thoracic horn of Macropelopia nebulosa (Meigen under light microscopy is visible as points, while under SEM we have found that it consists of a reticular structure with holes. By using SEM a more precise picture of the body structure of Chironomidae can be revealed. It allows researchers to explain inconsistencies in the existing descriptions of species. Another advantage of the SEM method is obtaining spatial images of the body and organs of Chironomidae. However, the SEM method also has some limitations. The main problem is dirt or debris (e.g. algae, mud, secretions, mucus, bacteria, etc., which often settles on the external surface of structures, especially those which are uneven or covered with hair. The dirt should be removed after collection of chironomid material because if left in place it can become chemically fixed to various surfaces. It unnecessarily remains at the surface and final microscopic images may contain artifacts that obscure chironomid structures being investigated. In this way many details of the surface are thus unreadable. The results reported here indicate that SEM examination helps us to identify new morphological features and details that will facilitate the identification of species of Chironomidae and may help to clarify the function of various parts of the body. Fast development of electron microscope technique allows us to learn more about structure of different organisms.

  16. Use of scanning electron microscopy to monitor nanofibre/cell interaction in digestive epithelial cells

    Energy Technology Data Exchange (ETDEWEB)

    Millaku, Agron, E-mail: agron.mi@hotmail.com [Limnos-Company for Applied Ecology Ltd, Podlimbarskega 31, 1000 Ljubljana (Slovenia); Drobne, Damjana [University of Ljubljana, Biotechnical Faculty, Department of Biology, Večna pot 111, 1000 Ljubljana (Slovenia); Centre of Excellence, Advanced Materials and Technologies for the Future (CO NAMASTE), Jamova cesta 39, 1000 Ljubljana (Slovenia); Centre of Excellence, Nanoscience and Nanotechnology (Nanocentre), Jamova cesta 39, 1000 Ljubljana (Slovenia); Torkar, Matjaz [Institute of Metals and Technology IMT, Lepi pot 11, 1000 Ljubljana (Slovenia); Jožef Stefan Institute, Condensed Matter Physics Department, Jamova cesta 39, 1000 Ljubljana (Slovenia); Novak, Sara [University of Ljubljana, Biotechnical Faculty, Department of Biology, Večna pot 111, 1000 Ljubljana (Slovenia); Remškar, Maja [Jožef Stefan Institute, Condensed Matter Physics Department, Jamova cesta 39, 1000 Ljubljana (Slovenia); Pipan-Tkalec, Živa [University of Ljubljana, Biotechnical Faculty, Department of Biology, Večna pot 111, 1000 Ljubljana (Slovenia)

    2013-09-15

    Graphical abstract: Scanning electron microscopy is particularly well suited to the observation of nanofibre/cell interaction in the endothelial cells lining the hepatopancreas. (a) Tungsten oxide nanofibres, (b) test organism Porcellio scaber and schematic appearance of digestive tubes, (c) digestive tube (hepatopancreas) prepared for SEM investigation, (d) digestive gland cells (C) with nanofibres (NF) embedded in the cell membrane and (e) nanofibres inserted deeply in the cells and damaged nanofibres due to peristalsis. -- Highlights: • Tungsten oxide nanofibres react physically with digestive gland epithelial cells in Porcellio scaber. • Physical peristaltic forces of lead to insertion of nanofibres into the cells. • No toxic responses as measured by conventional toxicity biomarkers were detected. • Physical interactions were observed in a majority of the investigated animals. -- Abstract: We provide data obtained by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) on the interaction of ingested tungsten nanofibers with epithelial cells of the digestive tubes of a test organism Porcellio scaber. Conventional toxicity endpoints including feeding behaviour, weight loss and mortality were also measured in each investigated animal. No toxicity was detected in any of exposed animals after 14 days of feeding on tungsten nanofiber dosed food, but when nanofibers enter the digestive system they can react with epithelial cells of the digestive tubes, becoming physically inserted into the cells. In this way, nanofibers can injure the epithelial cells of digestive gland tubes when they are ingested with food. Our SEM data suggest that peristaltic forces may have an important role, not predicted by in vitro experiments, in the interactions of nanomaterials with digestive intestinal cells.

  17. High-precision correlative fluorescence and electron cryo microscopy using two independent alignment markers☆

    Science.gov (United States)

    Schellenberger, Pascale; Kaufmann, Rainer; Siebert, C. Alistair; Hagen, Christoph; Wodrich, Harald; Grünewald, Kay

    2014-01-01

    Correlative light and electron microscopy (CLEM) is an emerging technique which combines functional information provided by fluorescence microscopy (FM) with the high-resolution structural information of electron microscopy (EM). So far, correlative cryo microscopy of frozen-hydrated samples has not reached better than micrometre range accuracy. Here, a method is presented that enables the correlation between fluorescently tagged proteins and electron cryo tomography (cryoET) data with nanometre range precision. Specifically, thin areas of vitrified whole cells are examined by correlative fluorescence cryo microscopy (cryoFM) and cryoET. Novel aspects of the presented cryoCLEM workflow not only include the implementation of two independent electron dense fluorescent markers to improve the precision of the alignment, but also the ability of obtaining an estimate of the correlation accuracy for each individual object of interest. The correlative workflow from plunge-freezing to cryoET is detailed step-by-step for the example of locating fluorescence-labelled adenovirus particles trafficking inside a cell. PMID:24262358

  18. High-precision correlative fluorescence and electron cryo microscopy using two independent alignment markers.

    Science.gov (United States)

    Schellenberger, Pascale; Kaufmann, Rainer; Siebert, C Alistair; Hagen, Christoph; Wodrich, Harald; Grünewald, Kay

    2014-08-01

    Correlative light and electron microscopy (CLEM) is an emerging technique which combines functional information provided by fluorescence microscopy (FM) with the high-resolution structural information of electron microscopy (EM). So far, correlative cryo microscopy of frozen-hydrated samples has not reached better than micrometre range accuracy. Here, a method is presented that enables the correlation between fluorescently tagged proteins and electron cryo tomography (cryoET) data with nanometre range precision. Specifically, thin areas of vitrified whole cells are examined by correlative fluorescence cryo microscopy (cryoFM) and cryoET. Novel aspects of the presented cryoCLEM workflow not only include the implementation of two independent electron dense fluorescent markers to improve the precision of the alignment, but also the ability of obtaining an estimate of the correlation accuracy for each individual object of interest. The correlative workflow from plunge-freezing to cryoET is detailed step-by-step for the example of locating fluorescence-labelled adenovirus particles trafficking inside a cell. © 2013 Published by Elsevier B.V.

  19. Scanning electron microscopy investigation of fibrin networks after thermal injury

    Directory of Open Access Journals (Sweden)

    Etheresia Pretorius

    2011-02-01

    Full Text Available Injury due to burning is known to impact on coagulation and haemostasis by disturbing the coagulation cascade and is also associated with impaired fibrinolysis. Also, venous thrombosis, pulmonary embolism and hypercoagulability are common during thermal injury. Using a Wistar albino rat model, we investigated in this study whether burn injury affects the ultrastructure of the fibrin networks. A typical fibrin network will contain mostly major, thick fibres with minor, thin fibres distributed amongst them. We found that the clot architecture changes after burn injury, showing more prominent minor, thin fibres in a netted appearance. Also, the clot showed areas of matted fibrin. We suggest that the thrombotic events associated with burn injury are due to the thickened and netlike areas formed when thrombin activates the coagulation cascade. This is due to impaired fibrinolysis activities, causing the resulting fibrin clots not to be successfully disseminated. Small fragments of these netted, clumped areas may therefore break loose and lead to thrombotic events after burn injuries. The current study therefore provided morphological evidence for thrombotic events associated with burn injury.

  20. Probing the electronic structure of graphene sheets with various thicknesses by scanning transmission X-ray microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Bai, Lili; Liu, Jinyin; Zhao, Guanqi; Gao, Jing; Sun, Xuhui, E-mail: xhsun@suda.edu.cn, E-mail: jzhong@suda.edu.cn; Zhong, Jun, E-mail: xhsun@suda.edu.cn, E-mail: jzhong@suda.edu.cn [Soochow University-Western University Centre for Synchrotron Radiation Research, Institute of Functional Nano and Soft Materials Laboratory (FUNSOM) and Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou 215123 (China)

    2013-12-16

    The electronic structure of an aggregation of graphene sheets with various thicknesses was probed by scanning transmission X-ray microscopy. A uniform oxidation of the graphene sheets in the flat area was observed regardless of the thickness, while in the folded area the result could be strongly affected by the geometry. Moreover, thick parts of the aggregation showed strong angle-dependence to the incident X-ray, while thin parts showed less angle-dependence, which might be related to the surface wrinkles and ripples. The electronic structure differences due to the geometry and thickness suggest a complicated situation in the aggregation of graphene sheets.

  1. In situ transmission electron microscopy analyses of thermally annealed self catalyzed GaAs nanowires grown by molecular beam epitaxy

    DEFF Research Database (Denmark)

    Ambrosini, S.; Wagner, Jakob Birkedal; Booth, Tim

    2011-01-01

    Self catalyzed GaAs nanowires grown on Si-treated GaAs substrates were studied with a transmission electron microscope before and after annealing at 600◦C. At room temperature the nanowires have a zincblende structure and are locally characterized by a high density of rotational twins and stackin...... faults. Selected area diffraction patterns and high-resolution transmission electron microscopy images show that nanowires undergo structural modifications upon annealing, suggesting a decrease of defect density following the thermal treatment....

  2. Cell culture and electron microscopy for identifying viruses in diseases of unknown cause.

    Science.gov (United States)

    Goldsmith, Cynthia S; Ksiazek, Thomas G; Rollin, Pierre E; Comer, James A; Nicholson, William L; Peret, Teresa C T; Erdman, Dean D; Bellini, William J; Harcourt, Brian H; Rota, Paul A; Bhatnagar, Julu; Bowen, Michael D; Erickson, Bobbie R; McMullan, Laura K; Nichol, Stuart T; Shieh, Wun-Ju; Paddock, Christopher D; Zaki, Sherif R

    2013-06-01

    During outbreaks of infectious diseases or in cases of severely ill patients, it is imperative to identify the causative agent. This report describes several events in which virus isolation and identification by electron microscopy were critical to initial recognition of the etiologic agent, which was further analyzed by additional laboratory diagnostic assays. Examples include severe acute respiratory syndrome coronavirus, and Nipah, lymphocytic choriomeningitis, West Nile, Cache Valley, and Heartland viruses. These cases illustrate the importance of the techniques of cell culture and electron microscopy in pathogen identification and recognition of emerging diseases.

  3. Electron microscopy of Mg/TiO{sub 2} photocatalyst morphology for deep desulfurization of diesel

    Energy Technology Data Exchange (ETDEWEB)

    Yin, Yee Cia, E-mail: gabrielle.ciayin@gmail.com [Department of Chemical Engineering, Universiti Teknologi PETRONAS, 31750 Tronoh, Perak (Malaysia); Kait, Chong Fai, E-mail: chongfaikait@petronas.com.my; Fatimah, Hayyiratul, E-mail: hayyiratulfatimah@yahoo.com; Wilfred, Cecilia, E-mail: cecili@petronas.com.my [Department of Fundamental and Applied Sciences, Universiti Teknologi PETRONAS, 31750 Tronoh, Perak (Malaysia)

    2015-07-22

    A series of Mg/TiO{sub 2} photocatalysts were prepared and characterized using Field Emission Scanning Electron Microscopy (FESEM) and High-Resolution Transmission Electron Microscopy (HRTEM). The average particle sizes of the photocatalysts were ranging from 25.7 to 35.8 nm. Incorporation of Mg on TiO{sub 2} did not lead to any surface lattice distortion to TiO{sub 2}. HRTEM data indicated the presence of MgO and Mg(OH){sub 2} mixture at low Mg loading while at higher Mg loading, the presence of lamellar Mg-oxyhydroxide intermediates and Mg(OH){sub 2}.

  4. The detection and influence of food soils on microorganisms on stainless steel using scanning electron microscopy and epifluorescence microscopy.

    Science.gov (United States)

    Whitehead, Kathryn A; Smith, Lindsay A; Verran, Joanna

    2010-07-31

    A range of food soils and components (complex [meat extract, fish extract, and cottage cheese extract]; oils [cholesterol, fish oil, and mixed fatty acids]; proteins [bovine serum albumin (BSA), fish peptones, and casein]; and carbohydrates [glycogen, starch, and lactose]) were deposited onto 304 2B finish stainless steel surfaces at different concentrations (10-0.001%). Scanning electron microscopy (SEM) and epifluorescence microscopy were used to visualise the cell and food soil distribution across the surface. Epifluorescence microscopy was also used to quantify the percentage of a field covered by cells or soil. At 10% concentration, most soils, with the exception of BSA and fish peptone were easily visualised using SEM, presenting differences in gross soil morphology and distribution. When soil was stained with acridine orange and visualised by epifluorescence microscopy, the limit of detection of the method varied between soils, but some (meat, cottage cheese and glycogen) were detected at the lowest concentrations used (0.001%). The decrease in soil concentration did not always relate to the surface coverage measurement. When 10% food soil was applied to a surface with Escherichia coli and compared, cell attachment differed depending on the nature of the soil. The highest percentage coverage of cells was observed on surfaces with fish extract and related products (fish peptone and fish oil), followed by carbohydrates, meat extract/meat protein, cottage cheese/casein and the least to the oils (cholesterol and mixed fatty acids). Cells could not be clearly observed in the presence of some food soils using SEM. Findings demonstrate that food soils heterogeneously covered stainless steel surfaces in differing patterns. The pattern and amount of cell attachment was related to food soil type rather than to the amount of food soil detected. This work demonstrates that in the study of conditioning film and cell retention on the hygienic properties of surfaces, SEM

  5. Understanding materials challenges for rechargeable ion batteries with in situ transmission electron microscopy

    Science.gov (United States)

    Yuan, Yifei; Amine, Khalil; Lu, Jun; Shahbazian-Yassar, Reza

    2017-01-01

    An in-depth understanding of material behaviours under complex electrochemical environment is critical for the development of advanced materials for the next-generation rechargeable ion batteries. The dynamic conditions inside a working battery had not been intensively explored until the advent of various in situ characterization techniques. Real-time transmission electron microscopy of electrochemical reactions is one of the most significant breakthroughs poised to enable radical shift in our knowledge on how materials behave in the electrochemical environment. This review, therefore, summarizes the scientific discoveries enabled by in situ transmission electron microscopy, and specifically emphasizes the applicability of this technique to address the critical challenges in the rechargeable ion battery electrodes, electrolyte and their interfaces. New electrochemical systems such as lithium–oxygen, lithium–sulfur and sodium ion batteries are included, considering the rapidly increasing application of in situ transmission electron microscopy in these areas. A systematic comparison between lithium ion-based electrochemistry and sodium ion-based electrochemistry is also given in terms of their thermodynamic and kinetic differences. The effect of the electron beam on the validity of in situ observation is also covered. This review concludes by providing a renewed perspective for the future directions of in situ transmission electron microscopy in rechargeable ion batteries.

  6. The application of Lorentz transmission electron microscopy to the study of lamellar magnetism in hematite-ilmenite

    DEFF Research Database (Denmark)

    Kasama, Takeshi; Dunin-Borkowski, Rafal E.; Asaka, T

    2009-01-01

    Lorentz transmission electron microscopy has been used to study line-scale exsolution microstructures in ilmenite-hematite, as part of a wider investigation of the lamellar magnetism hypothesis. Pronounced asymmetric contrast is visible in out-of-focus Lorentz images of ilmenite lamellae in hemat......Lorentz transmission electron microscopy has been used to study line-scale exsolution microstructures in ilmenite-hematite, as part of a wider investigation of the lamellar magnetism hypothesis. Pronounced asymmetric contrast is visible in out-of-focus Lorentz images of ilmenite lamellae...... in hematite. The likelihood that lamellar magnetism may be responsible for this contrast is assessed using simulations that incorporate interfacial magnetic moments on the (001) basal planes of hematite and ilmenite. The simulations suggest qualitatively that the asymmetric contrast is magnetic in origin...

  7. Stochastic Micro-Pattern for Automated Correlative Fluorescence - Scanning Electron Microscopy

    Science.gov (United States)

    Begemann, Isabell; Viplav, Abhiyan; Rasch, Christiane; Galic, Milos

    2015-01-01

    Studies of cellular surface features gain from correlative approaches, where live cell information acquired by fluorescence light microscopy is complemented by ultrastructural information from scanning electron micrographs. Current approaches to spatially align fluorescence images with scanning electron micrographs are technically challenging and often cost or time-intensive. Relying exclusively on open-source software and equipment available in a standard lab, we have developed a method for rapid, software-assisted alignment of fluorescence images with the corresponding scanning electron micrographs via a stochastic gold micro-pattern. Here, we provide detailed instructions for micro-pattern production and image processing, troubleshooting for critical intermediate steps, and examples of membrane ultra-structures aligned with the fluorescence signal of proteins enriched at such sites. Together, the presented method for correlative fluorescence – scanning electron microscopy is versatile, robust and easily integrated into existing workflows, permitting image alignment with accuracy comparable to existing approaches with negligible investment of time or capital. PMID:26647824

  8. Scanning electron microscopy of individual nanoparticle bio-markers in liquid

    Energy Technology Data Exchange (ETDEWEB)

    Liv, Nalan, E-mail: n.liv@tudelft.nl; Lazić, Ivan; Kruit, Pieter; Hoogenboom, Jacob P.

    2014-08-01

    We investigated SEM imaging of nanoparticle biomarkers suspended below a thin membrane, with the ultimate goal of integrating functional fluorescence and structural SEM measurements of samples kept at ambient or hydrated conditions. In particular, we investigated how resolving power in liquid SEM is affected by the interaction of the electron beam with the membrane. Simulations with the Geant4-based Monte Carlo scheme developed by Kieft and Bosch (2008) [1] are compared to experimental results with suspended nanoparticles. For 20 nm and 50 nm thin membranes, we found a beam broadening of 1.5 nm and 3 nm, respectively, with an excellent agreement between simulations and experiments. 15 nm Au nanoparticles and bio-functionalized core-shell quantum dots can be individually resolved in denser clusters. We demonstrated the imaging of single EGF-conjugated quantum dots docked at filopodia during cellular uptake with both fluorescence microscopy and SEM simultaneously. These results open novel opportunities for correlating live fluorescence microscopy with structural electron microscopy. - Highlights: • We investigate the achievable resolution in liquid scanning electron microscopy (SEM). • We demonstrate liquid SEM imaging of individual fluorescent nanoparticle bio-markers • We show imaging of cellular QDot uptake with simultaneous fluorescence microscopy and SEM. • The positions of individual QDots can be resolved with details on cellular structure.

  9. Construction and Organization of a BSL-3 Cryo-Electron Microscopy Laboratory at UTMB

    OpenAIRE

    Michael B. Sherman; Trujillo, Juan; Leahy, Ian; Razmus, Dennis; DeHate, Robert; Lorcheim, Paul; Czarneski, Mark A.; Zimmerman, Domenica; Newton, Je T’Aime M.; Haddow, Andrew D.; Weaver, Scott C.

    2012-01-01

    A unique cryo-electron microscopy facility has been designed and constructed at the University of Texas Medical Branch (UTMB) to study the three-dimensional organization of viruses and bacteria classified as select agents at biological safety level (BSL)-3, and their interactions with host cells. A 200 keV high-end cryo-electron microscope was installed inside a BSL-3 containment laboratory and standard operating procedures were developed and implemented to ensure its safe and efficient opera...

  10. On the feasibility to investigate point defects by advanced electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Kisielowski, C.; Jinschek, J.R.

    2002-10-02

    Transmission Electron Microscopy evolves rapidly as a primary tool to investigate nano structures on a truly atomic level. Its resolution reaches into the sub Angstrom region by now. Together with a better correction of lens aberrations, sensitivities are drastically enhanced. Utilizing advanced electron microscopes, it is feasible to promote experiments that aim to detect single atoms. This enables local investigations of non-stoichiometry. This paper reviews the current state-of-the-art.

  11. A Simple Transmission Electron Microscopy Method for Fast Thickness Characterization of Suspended Graphene and Graphite Flakes.

    Science.gov (United States)

    Rubino, Stefano; Akhtar, Sultan; Leifer, Klaus

    2016-02-01

    We present a simple, fast method for thickness characterization of suspended graphene/graphite flakes that is based on transmission electron microscopy (TEM). We derive an analytical expression for the intensity of the transmitted electron beam I 0(t), as a function of the specimen thickness t (tgraphene/graphite, the method we propose has the advantage of being simple and fast, requiring only the acquisition of bright-field images.

  12. UROX 2.0: an interactive tool for fitting atomic models into electron-microscopy reconstructions.

    Science.gov (United States)

    Siebert, Xavier; Navaza, Jorge

    2009-07-01

    Electron microscopy of a macromolecular structure can lead to three-dimensional reconstructions with resolutions that are typically in the 30-10 A range and sometimes even beyond 10 A. Fitting atomic models of the individual components of the macromolecular structure (e.g. those obtained by X-ray crystallography or nuclear magnetic resonance) into an electron-microscopy map allows the interpretation of the latter at near-atomic resolution, providing insight into the interactions between the components. Graphical software is presented that was designed for the interactive fitting and refinement of atomic models into electron-microscopy reconstructions. Several characteristics enable it to be applied over a wide range of cases and resolutions. Firstly, calculations are performed in reciprocal space, which results in fast algorithms. This allows the entire reconstruction (or at least a sizeable portion of it) to be used by taking into account the symmetry of the reconstruction both in the calculations and in the graphical display. Secondly, atomic models can be placed graphically in the map while the correlation between the model-based electron density and the electron-microscopy reconstruction is computed and displayed in real time. The positions and orientations of the models are refined by a least-squares minimization. Thirdly, normal-mode calculations can be used to simulate conformational changes between the atomic model of an individual component and its corresponding density within a macromolecular complex determined by electron microscopy. These features are illustrated using three practical cases with different symmetries and resolutions. The software, together with examples and user instructions, is available free of charge at http://mem.ibs.fr/UROX/.

  13. Analysis of acute brain slices by electron microscopy: a correlative light-electron microscopy workflow based on Tokuyasu cryo-sectioning.

    Science.gov (United States)

    Loussert Fonta, Celine; Leis, Andrew; Mathisen, Cliff; Bouvier, David S; Blanchard, Willy; Volterra, Andrea; Lich, Ben; Humbel, Bruno M

    2015-01-01

    Acute brain slices are slices of brain tissue that are kept vital in vitro for further recordings and analyses. This tool is of major importance in neurobiology and allows the study of brain cells such as microglia, astrocytes, neurons and their inter/intracellular communications via ion channels or transporters. In combination with light/fluorescence microscopies, acute brain slices enable the ex vivo analysis of specific cells or groups of cells inside the slice, e.g. astrocytes. To bridge ex vivo knowledge of a cell with its ultrastructure, we developed a correlative microscopy approach for acute brain slices. The workflow begins with sampling of the tissue and precise trimming of a region of interest, which contains GFP-tagged astrocytes that can be visualised by fluorescence microscopy of ultrathin sections. The astrocytes and their surroundings are then analysed by high resolution scanning transmission electron microscopy (STEM). An important aspect of this workflow is the modification of a commercial cryo-ultramicrotome to observe the fluorescent GFP signal during the trimming process. It ensured that sections contained at least one GFP astrocyte. After cryo-sectioning, a map of the GFP-expressing astrocytes is established and transferred to correlation software installed on a focused ion beam scanning electron microscope equipped with a STEM detector. Next, the areas displaying fluorescence are selected for high resolution STEM imaging. An overview area (e.g. a whole mesh of the grid) is imaged with an automated tiling and stitching process. In the final stitched image, the local organisation of the brain tissue can be surveyed or areas of interest can be magnified to observe fine details, e.g. vesicles or gold labels on specific proteins. The robustness of this workflow is contingent on the quality of sample preparation, based on Tokuyasu's protocol. This method results in a reasonable compromise between preservation of morphology and maintenance of

  14. EVALUATION OF COMPUTER-CONTROLLED SCANNING ELECTRON MICROSCOPY APPLIED TO AN AMBIENT URBAN AEROSOL SAMPLE

    Science.gov (United States)

    Recent interest in monitoring and speciation of particulate matter has led to increased application of scanning electron microscopy (SEM) coupled with energy-dispersive x-ray analysis (EDX) to individual particle analysis. SEM/EDX provides information on the size, shape, co...

  15. Scanning electron microscopy and X-ray spectroscopy applied to mycelial phase of sporothrix schenckii

    Directory of Open Access Journals (Sweden)

    M. Thibaut

    1975-04-01

    Full Text Available Scanning electron microscopy applied to the mycelial phase of Sporothrix schenckii shows a matted mycelium with conidia of a regular pattern. X-Ray microanalysis applied in energy dispersive spectroscopy and also in wavelength dispersive spectroscopy reveals the presence of several elements of Mendeleef's classification.

  16. Structural dynamics of gas-phase molybdenum nanoclusters : A transmission electron microscopy study

    NARCIS (Netherlands)

    Vystavel, T; Koch, SA; Palasantzas, G; De Hosson, JTM

    2005-01-01

    In this paper we study structural aspects of molybdenum clusters by transmission electron microscopy. The deposited clusters with sizes 4 nm or larger show a body-centered crystal (bcc) structure. The clusters are self-assembled from smaller structural units and form cuboids with a typical size of 4

  17. Cryo-transmission electron microscopy of a superstructure of fluid dioleoylphosphatidylcholine (DOPC) membranes

    DEFF Research Database (Denmark)

    Klösgen, B; Helfrich, W

    1997-01-01

    Using cryo-transmission electron microscopy, we have obtained abundant and reproducible evidence for a superstructure of dioleoylphosphatidylcholine (DOPC) bilayers. Dispersions of vesicles were prepared by gentle shaking of a 2% suspension of DOPC in water followed in part by extrusion through a...

  18. Multi-color electron microscopy by element-guided identification of cells, organelles and molecules

    NARCIS (Netherlands)

    Scotuzzi, M.; Kuipers, Jeroen; Wensveen, D.I.; De Boer, Pascal; Hagen, C.W.; Hoogenboom, J.P.; Giepmans, Ben N.G.

    2017-01-01

    Cellular complexity is unraveled at nanometer resolution using electron microscopy (EM), but interpretation of macromolecular functionality is hampered by the difficulty in interpreting grey-scale images and the unidentified molecular content. We perform large-scale EM on mammalian tissue

  19. Morphologic differences observed by scanning electron microscopy according to the reason for pseudophakic IOL explantation

    DEFF Research Database (Denmark)

    Fernandez-Buenaga, Roberto; Alio, Jorge L.; Ramirez, Jose M.

    2015-01-01

    Purpose To compare variations in surface morphology, as studied by scanning electron microscopy (SEM), of explanted intraocular lenses (IOLs) concerning the cause leading to the explantation surgery. Methods In this prospective multicenter study, explanted IOLs were analyzed by SEM and energy-dis...

  20. Current status and future directions for in situ transmission electron microscopy

    DEFF Research Database (Denmark)

    Taheri, Mitra L.; Stach, Eric A.; Arslan, Ilke

    2016-01-01

    This review article discusses the current and future possibilities for the application of in situ transmission electron microscopy to reveal synthesis pathways and functional mechanisms in complex and nanoscale materials. The findings of a group of scientists, representing academia, government labs...

  1. Ceria-catlyzed soot oxidation studied by environmental transmission electron microscopy

    DEFF Research Database (Denmark)

    Simonsen, S.B.; Dahl, S.; Johnson, Erik

    2008-01-01

    Environmental tranmission electron microscopy (ETEM) was used to monitor in situ ceria-catalyzed oxidation of soot in relation to diesel engine emission control.  From time-lapsed ETEM image series of soot particles in contact with CeO2. or with Al2O3 as inert reference, mechanistic and kinetic...

  2. Integrative Modeling of Biomolecular Complexes : HADDOCKing with Cryo-Electron Microscopy Data

    NARCIS (Netherlands)

    van Zundert, Gydo C P; Melquiond, Adrien S J; Bonvin, Alexandre M J J

    2015-01-01

    Protein-protein interactions play a central role in all cellular processes. Insight into their atomic architecture is therefore of paramount importance. Cryo-electron microscopy (cryo-EM) is capable of directly imaging large macromolecular complexes. Unfortunately, the resolution is usually not

  3. Scanning electron microscopy with polarization analysis for multilayered chiral spin textures

    NARCIS (Netherlands)

    Lucassen, Juriaan; Kloodt-Twesten, Fabian; Frömter, Robert; Oepen, Hans Peter; Duine, Rembert A.|info:eu-repo/dai/nl/304830127; Swagten, Henk J. M.; Koopmans, Bert; Lavrijsen, Reinoud

    We show that scanning electron microscopy with polarization analysis (SEMPA) that is sensitive to both in-plane magnetization components can be used to image the out-of-plane magnetized multi-domain state in multilayered chiral spin textures. By depositing a thin layer of Fe on top of the multilayer

  4. Electron Microscopy Characterization of Aerosols Collected at Mauna Loa Observatory During Asian Dust Storm Event

    Science.gov (United States)

    Atmospheric aerosol particles have a significant influence on global climate due to their ability to absorb and scatter incoming solar radiation. Size, composition, and morphology affect a particle’s radiative properties and these can be characterized by electron microscopy. Lo...

  5. Quantitative analysis of structural inhomogeneity in nanomaterials using transmission electron microscopy

    Czech Academy of Sciences Publication Activity Database

    Klinger, Miloslav; Polívka, Leoš; Jäger, Aleš; Tyunina, Marina

    2016-01-01

    Roč. 49, Jun (2016), 762-770 ISSN 1600-5767 R&D Projects: GA ČR GBP108/12/G043; GA ČR GA15-15123S Institutional support: RVO:68378271 Keywords : transmission electron microscopy * structural inhomogeneity * lattice parameters * image processing Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.495, year: 2016

  6. RGB color coded images in scanning electron microscopy of biological surfaces

    Czech Academy of Sciences Publication Activity Database

    Kofroňová, Olga; Benada, Oldřich

    2017-01-01

    Roč. 61, č. 3 (2017), s. 349-352 ISSN 0001-723X R&D Projects: GA MŠk(CZ) LO1509; GA ČR(CZ) GA16-20229S Institutional support: RVO:61388971 Keywords : Biological surfaces * Color images * Scanning electron microscopy Subject RIV: EE - Microbiology, Virology Impact factor: 0.673, year: 2016

  7. Structure of the ATP synthase from chloroplasts studied by electron microscopy and image processing

    NARCIS (Netherlands)

    Boekema, Egbert J.; Heel, Marin van; Gräber, Peter

    1988-01-01

    The structure of the hydrophilic part of the ATP synthase from chloroplasts (CF1) has been investigated by electron microscopy of negatively stained samples. The staining conditions, which are generally critical for such small objects as CF1, could be improved by mixing CF1 samples with a much

  8. A general mechanism of ribosome dimerization revealed by single-particle cryo-electron microscopy

    NARCIS (Netherlands)

    Franken, Linda; Oostergetel, Gerrit; Pijning, Tjaard; Puri, Pranav; Arkhipova, Valentina Ivanovna; Boekema, Egbert; Poolman, Berend; Guskov, Albert

    2017-01-01

    Bacteria downregulate their ribosomal activity through dimerization of 70S ribosomes, yielding inactive 100S complexes. In Escherichia coli, dimerization is mediated by the hibernation promotion factor (HPF) and ribosome modulation factor. Here we report the cryo-electron microscopy study on 100S

  9. Structure of the light harvesting antenna from Rhodospirillum molischianum studied by electron microscopy

    NARCIS (Netherlands)

    Boonstra, Arjen F.; Germeroth, Lothar; Boekema, Egbert J.

    1994-01-01

    The structure of two types of isolated light-harvesting antenna complexes from Rhodospirillum molischianum was studied by electron microscopy and image analysis. The B870 reaction center complex forms an almost circular particle with a diameter in the plane of the membrane of about 10.7-11.2 nm. A

  10. Thermal stability of catalytically grown multi-walled carbon nanotubes observed in transmission electron microscopy

    DEFF Research Database (Denmark)

    Wang, Cheng-Yu; Liu, Chuan-Pu; Boothroyd, Chris

    2009-01-01

    The thermal stability of multi-walled carbon nanotubes (MWCNTs) was assessed in situ by transmission electron microscopy. Upon heating, Ni catalysts in MWC-NTs containing bamboo structures shrank from the tail due to evaporation, leading to additional bamboo formation and tube elongation at 800...

  11. Electron microscopy of helical filaments: rediscovering buried treasures in negative stain.

    Science.gov (United States)

    Egelman, Edward H; Amos, Linda A

    2009-09-01

    Although negative stain electron microscopy is a wonderfully simple way of directly visualizing protein complexes and other biological macromolecules, the images are not really comparable to those of objects seen in everyday life. The failure to appreciate this has recently led to an incorrect interpretation of RecA-family filament structures.

  12. Quantifying the growth of individual graphene layers by in situ environmental transmission electron microscopy

    DEFF Research Database (Denmark)

    Kling, Jens; Hansen, Thomas Willum; Wagner, Jakob Birkedal

    2016-01-01

    The growth dynamics of layered carbon is studied by means of in situ transmission electron microscopy in order to obtain a deeper insight into the growth by chemical vapor deposition, which at present is the technique of choice for growing layered carbon. In situ growth of layered carbon structures...

  13. Precise and unbiased estimation of astigmatism and defocus in transmission electron microscopy

    NARCIS (Netherlands)

    Vulovic, M.; Franken, E.; Ravelli, R.B.G.; Van Vliet, L.J.; Rieger, B.

    2012-01-01

    Defocus and twofold astigmatism are the key parameters governing the contrast transfer function (CTF) in transmission electron microscopy (TEM) of weak phase objects. We present a new algorithm to estimate these aberrations and the associated uncertainties. Tests show very good agreement between

  14. In-situ transmission electron microscopy : on moving dislocations and mobile grain boundaries

    NARCIS (Netherlands)

    De Hosson, J. T. M.; Soer, W.

    This paper delineates the possibilities of utilizing in situ transmission electron microscopy to unravel dislocation-g rain boundary interactions. In situ nanoindentation experiments have been conducted in TEM on ultrafine-grained Al and Al-Mg films with varying Mg contents. The observed propagation

  15. Scanning electron microscopy of the oral apparatus and buccopharyngeal cavity of Atelognathus salai larvae (Anura, Neobatrachia

    Directory of Open Access Journals (Sweden)

    Dinorah D. Echeverría

    2006-09-01

    Full Text Available The aim of this study is to describe the horny structures of the buccal apparatus and buccopharyngeal cavity of A. salai by means ofscanning electron microscopy (SEM, and to compare them to those of the other known species of Atelognathus and related genera.

  16. Pollen grain surface in Vaccinium myrtillus as seen in scanning electron microscopy

    Directory of Open Access Journals (Sweden)

    Józef Kocoń

    2014-01-01

    Full Text Available Pollen grain surface of Vaccinium myrtillus L. was analyzed by scanning electron microscopy. Pollen grains remain in tetrahedral tetrads. Grain surface is verrucose, consisting of thick, irregularly shaped muri, surrounding small, round or oval lumina. The surface of the muri is fissured, and minute papillae can also be noted.

  17. THALLUS SURFACES IN COCCOCARPIACEAE AND PANNARIACEAE (LICHENIZED ASCOMYCETES) VIEWED WITH SCANNING ELECTRON-MICROSCOPY

    NARCIS (Netherlands)

    LUMBSCH, HT; KOTHE, HW

    1992-01-01

    The thallus surfaces of species belonging to the Coccocarpiaceae and Pannariaceae were studied using scanning electron microscopy (SEM). A pored epicortex was shown in Coccocarpia ssp., Degelia gayana and D. plumbea. In the other species studied no definite pores were found. The probable systematic

  18. Cold-induced imbibition damage of lettuce embryos: A study using cryo-scanning electron microscopy

    NARCIS (Netherlands)

    Nijsse, J.; Walther, P.; Hoekstra, F.

    2004-01-01

    The impact of rehydration on a multicellular organism was studied in lettuce (Lactuca sativa L.) embryos, using cryo-scanning electron microscopy (cryo-SEM). Naked embryos were sensitive to imbibitional stress, whereas embryos with an intact, thick-walled endosperm were not. Imbibitional injury to

  19. Accuracy of surface strain measurements from transmission electron microscopy images of nanoparticles

    DEFF Research Database (Denmark)

    Madsen, Jacob; Liu, Pei; Wagner, Jakob Birkedal

    2017-01-01

    Strain analysis from high-resolution transmission electron microscopy (HRTEM) images offers a convenient tool for measuring strain in materials at the atomic scale. In this paper we present a theoretical study of the precision and accuracy of surface strain measurements directly from aberration-c...

  20. Application of a grating coupler for surface plasmon polariton excitation in a photoemission electron microscopy experiment

    DEFF Research Database (Denmark)

    Leißner, Till; Jauernik, Stephan; Lemke, Christoph

    Surface plasmon polariton (SPP) excitation at a gold-vacuum interface via 800 nm light pulses mediated by a periodic array of gold ridges is probed at high lateral resolution by means of photoemission electron microscopy (PEEM). We directly monitor and quantify the coupling properties as a function...

  1. The innate immune response against mycobacterial infection : analysis by a combination of light and electron microscopy

    NARCIS (Netherlands)

    Hosseini, Rohola

    2015-01-01

    In this thesis the zebrafish tail fin infection model is presented, which enables the study of a complex immune response towards (myco)bacterial infection using a combination of light and electron microscopy. The induction of autophagy upon a mycobacterial infection as an important innate immune

  2. In situ imaging of electromigration-induced nanogap formation by transmission electron microscopy

    NARCIS (Netherlands)

    Heersche, H.B.; Lientschnig, G.; O'Neill, K.; Van der Zant, H.S.J.; Zandbergen, H.W.

    2007-01-01

    The authors imaged electromigration-induced nanogap formation in situ by transmission electron microscopy. Real-time video recordings show that edge voids form near the cathode side. The polycrystalline gold wires narrow down until a single-grain boundary intersects the constriction along which the

  3. High-speed nanoscale characterization of dewetting via dynamic transmission electron microscopy

    Science.gov (United States)

    Hihath, Sahar; Santala, Melissa K.; Campbell, Geoffrey; van Benthem, Klaus

    2016-08-01

    The dewetting of thin films can occur in either the solid or the liquid state for which different mass transport mechanisms are expected to control morphological changes. Traditionally, dewetting dynamics have been examined on time scales between several seconds to hours, and length scales ranging between nanometers and millimeters. The determination of mass transport mechanisms on the nanoscale, however, requires nanoscale spatial resolution and much shorter time scales. This study reports the high-speed observation of dewetting phenomena for kinetically constrained Ni thin films on crystalline SrTiO3 substrates. Movie-mode Dynamic Transmission Electron Microscopy (DTEM) was used for high-speed image acquisition during thin film dewetting at different temperatures. DTEM imaging confirmed that the initial stages of film agglomeration include edge retraction, hole formation, and growth. Finite element modeling was used to simulate temperature distributions within the DTEM samples after laser irradiation with different energies. For pulsed laser irradiation at 18 μJ, experimentally observed hole growth suggests that Marangoni flow dominates hole formation in the liquid nickel film. After irradiation with 13.8 μJ, however, the observations suggest that dewetting was initiated by nucleation of voids followed by hole growth through solid-state surface diffusion.

  4. Structure of Human M-type Phospholipase A2 Receptor Revealed by Cryo-Electron Microscopy.

    Science.gov (United States)

    Dong, Yue; Cao, Longxing; Tang, Hua; Shi, Xiangyi; He, Yongning

    2017-12-08

    M-type phospholipase A2 receptor (M-PLA2R) is a member of the mannose receptor family and known as the receptor of secretory phospholipase A2s. It has also been identified as the major autoantigen of idiopathic membranous nephropathy, one of the most common causes for nephrotic syndrome in adults. Here we determine the structure of human M-PLA2R ectodomain by cryo-electron microscopy. The results show that the ectodomain has high internal flexibility and forms a compact dual-ring-shaped conformation at acidic pH and adopts extended conformations at basic pH. The inter-domain interactions of human M-PLA2R are explored by the binding studies with individual domains, showing the mechanism of the conformational change. In addition, the biochemical data suggest that mouse M-PLA2R recognizes mouse secretory phospholipase A2-G1B only at physiological or basic pH, rather than at acidic pH. These results suggest that the pH-dependent conformational change might play important roles in the functional activities of M-PLA2R such as ligand binding and release, and may also be relevant to the immunogenicity in membranous nephropathy. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Electronic cigarettes in the USA: a summary of available toxicology data and suggestions for the future.

    Science.gov (United States)

    Orr, Michael S

    2014-05-01

    To review the available evidence evaluating the toxicological profiles of electronic cigarettes (e-cigarettes) in order to understand the potential impact of e-cigarettes on individual users and the public health. Systematic literature searches were conducted between October 2012 and October 2013 using five electronic databases. Search terms such as 'e-cigarettes' and 'electronic delivery devices' were used to identify the toxicology information for e-cigarettes. As of October 2013, the scientific literature contains very limited information regarding the toxicity of e-cigarettes commercially available in the USA. While some preliminary toxicology data suggests that e-cigarette users are exposed to lower levels of toxicants relative to cigarette smokers, the data available is extremely limited at this time. At present, there is insufficient toxicological data available to perform thorough risk assessment analyses for e-cigarettes; few toxicology studies evaluating e-cigarettes have been conducted to date, and standard toxicological testing paradigms have not been developed for comparing disparate types of tobacco products such as e-cigarettes and traditional cigarettes. Overall, the limited toxicology data on e-cigarettes in the public domain is insufficient to allow a thorough toxicological evaluation of this new type of tobacco product. In the future, the acquisition of scientific datasets that are derived from scientifically robust standard testing paradigms, include comprehensive chemical characterisation of the aerosol, provide information on users' toxicant exposure levels, and from studies replicated by independent researchers will improve the scientific community's ability to perform robust toxicological evaluations of e-cigarettes.

  6. Investigating Ceria Nanocrystals Uptake by Glioblastoma Multiforme Cells and its Related Effects: An Electron Microscopy Study

    KAUST Repository

    Aloufi, Bader

    2017-01-22

    Cerium oxide nanoparticles have been utilized widely nowadays in cancer research. It has been suggested by many studies that these nanoparticles are capable of having dual antioxidant behavior in healthy and cancer microenvironment; where in physiological condition, they act as antioxidant and do not affect the healthy cells, while in tumor-like condition; they act as an oxidase, and result in a selective killing for the cancer cells. In this experiment, the interaction of nanoceria with glioblastoma and healthy astrocyte cells was examined, and further correlated with the in vitro cytotoxic effects of various nanoceria concentrations (100 and 300 µg/ml) and exposure times (12, 24, and 48 hours). Electron microscopes were used to investigate the cellular-NPs interactions, and to examine the related cytotoxic effects in combination with trypan blue and propidium iodide viability assays. Our data suggest the following results. First, the two cell lines demonstrated capability of taken up the ceria through endocytosis pathway, where the NPs were recognized engulfed by double membrane vesicles at various regions over the cellular cytoplasm. Secondly, cerium oxide nanoparticles were found to affect the glioblastoma cells, but not so severely the corresponding healthy astrocytes at the various concentrations and incubation times, as revealed by the viability assays and the electron microscopy analysis. Thirdly, the viability of the glioblastoma cells after the treatment displayed a declined trend when increasing the ceria concentrations, but did not show such dependency with regard to the different time points. In all cases, the healthy astrocyte cells showed slight alterations in mitochondrial shape which did not influence their viability. Among the various nanoceria concentrations and exposure times, the most efficient dose of treatment was found to be with a concentration of 300 µg/ml at a time point of 24-hour, where higher reduction on the viability of

  7. Morphology and structure of lipoproteins revealed by an optimized negative-staining protocol of electron microscopy[S

    Science.gov (United States)

    Zhang, Lei; Song, James; Cavigiolio, Giorgio; Ishida, Brian Y.; Zhang, Shengli; Kane, John P.; Weisgraber, Karl H.; Oda, Michael N.; Rye, Kerry-Anne; Pownall, Henry J.; Ren, Gang

    2011-01-01

    Plasma lipoprotein levels are predictors of risk for coronary artery disease. Lipoprotein structure-function relationships provide important clues that help identify the role of lipoproteins in cardiovascular disease. The compositional and conformational heterogeneity of lipoproteins are major barriers to the identification of their structures, as discovered using traditional approaches. Although electron microscopy (EM) is an alternative approach, conventional negative staining (NS) produces rouleau artifacts. In a previous study of apolipoprotein (apo)E4-containing reconstituted HDL (rHDL) particles, we optimized the NS method in a way that eliminated rouleaux. Here we report that phosphotungstic acid at high buffer salt concentrations plays a key role in rouleau formation. We also validate our protocol for analyzing the major plasma lipoprotein classes HDL, LDL, IDL, and VLDL, as well as homogeneously prepared apoA-I-containing rHDL. High-contrast EM images revealed morphology and detailed structures of lipoproteins, especially apoA-I-containing rHDL, that are amenable to three-dimensional reconstruction by single-particle analysis and electron tomography. PMID:20978167

  8. Genetically targeted 3D visualisation of Drosophila neurons under Electron Microscopy and X-Ray Microscopy using miniSOG.

    Science.gov (United States)

    Ng, Julian; Browning, Alyssa; Lechner, Lorenz; Terada, Masako; Howard, Gillian; Jefferis, Gregory S X E

    2016-12-13

    Large dimension, high-resolution imaging is important for neural circuit visualisation as neurons have both long- and short-range patterns: from axons and dendrites to the numerous synapses at terminal endings. Electron Microscopy (EM) is the favoured approach for synaptic resolution imaging but how such structures can be segmented from high-density images within large volume datasets remains challenging. Fluorescent probes are widely used to localise synapses, identify cell-types and in tracing studies. The equivalent EM approach would benefit visualising such labelled structures from within sub-cellular, cellular, tissue and neuroanatomical contexts. Here we developed genetically-encoded, electron-dense markers using miniSOG. We demonstrate their ability in 1) labelling cellular sub-compartments of genetically-targeted neurons, 2) generating contrast under different EM modalities, and 3) segmenting labelled structures from EM volumes using computer-assisted strategies. We also tested non-destructive X-ray imaging on whole Drosophila brains to evaluate contrast staining. This enabled us to target specific regions for EM volume acquisition.

  9. The Observation of Martensite and Magnetic Domain Structures in Ni53Mn24Ga23 Shape Memory Alloys by Scanning Electron Acoustic Microscopy and Scanning Thermal Microscopy

    Science.gov (United States)

    Zhao, Kun-Yu; Zeng, Hua-Rong; Song, Hong-Zhang; Hui, Sen-Xing; Li, Guo-Rong; Yin, Qing-Rui

    2012-05-01

    We present observations of martensite variants and ferromagnetic domain structures of Ni53Mn24Ga23 ferromagnetic shape memory alloys with a pure tetragonal martensitic phase by using scanning electron acoustic microscopy (SEAM) and scanning thermal microscopy (SThM). Electron acoustic images show a polycrystalline morphology with martensite variants. Direct coincidence between crystallographic martensitic twin variants and magnetic domains is found. A domain-like structure, obtained by SThM, is firstly reported, and then confirmed by magnetic force microscopy (MFM). The experimental results will be helpful for investigating the local thermal properties of ferromagnets and understanding the relationship between martensite variants and magnetic domains.

  10. Characterization of Sulfur and Nanostructured Sulfur Battery Cathodes in Electron Microscopy Without Sublimation Artifacts

    Energy Technology Data Exchange (ETDEWEB)

    Levin, Barnaby D. A.; Zachman, Michael J.; Werner, Jörg G.; Sahore, Ritu; Nguyen, Kayla X.; Han, Yimo; Xie, Baoquan; Ma, Lin; Archer, Lynden A.; Giannelis, Emmanuel P.; Wiesner, Ulrich; Kourkoutis, Lena F.; Muller, David A.

    2017-02-01

    Abstract

    Lithium sulfur (Li–S) batteries have the potential to provide higher energy storage density at lower cost than conventional lithium ion batteries. A key challenge for Li–S batteries is the loss of sulfur to the electrolyte during cycling. This loss can be mitigated by sequestering the sulfur in nanostructured carbon–sulfur composites. The nanoscale characterization of the sulfur distribution within these complex nanostructured electrodes is normally performed by electron microscopy, but sulfur sublimates and redistributes in the high-vacuum conditions of conventional electron microscopes. The resulting sublimation artifacts render characterization of sulfur in conventional electron microscopes problematic and unreliable. Here, we demonstrate two techniques, cryogenic transmission electron microscopy (cryo-TEM) and scanning electron microscopy in air (airSEM), that enable the reliable characterization of sulfur across multiple length scales by suppressing sulfur sublimation. We use cryo-TEM and airSEM to examine carbon–sulfur composites synthesized for use as Li–S battery cathodes, noting several cases where the commonly employed sulfur melt infusion method is highly inefficient at infiltrating sulfur into porous carbon hosts.

  11. Characterization of Sulfur and Nanostructured Sulfur Battery Cathodes in Electron Microscopy Without Sublimation Artifacts.

    Science.gov (United States)

    Levin, Barnaby D A; Zachman, Michael J; Werner, Jörg G; Sahore, Ritu; Nguyen, Kayla X; Han, Yimo; Xie, Baoquan; Ma, Lin; Archer, Lynden A; Giannelis, Emmanuel P; Wiesner, Ulrich; Kourkoutis, Lena F; Muller, David A

    2017-02-01

    Lithium sulfur (Li-S) batteries have the potential to provide higher energy storage density at lower cost than conventional lithium ion batteries. A key challenge for Li-S batteries is the loss of sulfur to the electrolyte during cycling. This loss can be mitigated by sequestering the sulfur in nanostructured carbon-sulfur composites. The nanoscale characterization of the sulfur distribution within these complex nanostructured electrodes is normally performed by electron microscopy, but sulfur sublimates and redistributes in the high-vacuum conditions of conventional electron microscopes. The resulting sublimation artifacts render characterization of sulfur in conventional electron microscopes problematic and unreliable. Here, we demonstrate two techniques, cryogenic transmission electron microscopy (cryo-TEM) and scanning electron microscopy in air (airSEM), that enable the reliable characterization of sulfur across multiple length scales by suppressing sulfur sublimation. We use cryo-TEM and airSEM to examine carbon-sulfur composites synthesized for use as Li-S battery cathodes, noting several cases where the commonly employed sulfur melt infusion method is highly inefficient at infiltrating sulfur into porous carbon hosts.

  12. Cathodoluminescence-activated nanoimaging: noninvasive near-field optical microscopy in an electron microscope.

    Science.gov (United States)

    Bischak, Connor G; Hetherington, Craig L; Wang, Zhe; Precht, Jake T; Kaz, David M; Schlom, Darrell G; Ginsberg, Naomi S

    2015-05-13

    We demonstrate a new nanoimaging platform in which optical excitations generated by a low-energy electron beam in an ultrathin scintillator are used as a noninvasive, near-field optical scanning probe of an underlying sample. We obtain optical images of Al nanostructures with 46 nm resolution and validate the noninvasiveness of this approach by imaging a conjugated polymer film otherwise incompatible with electron microscopy due to electron-induced damage. The high resolution, speed, and noninvasiveness of this "cathodoluminescence-activated" platform also show promise for super-resolution bioimaging.

  13. Three-dimensional reconstruction of Heterocapsa circularisquama RNA virus by electron cryo-microscopy.

    Science.gov (United States)

    Miller, Jennifer L; Woodward, Jeremy; Chen, Shaoxia; Jaffer, Mohammed; Weber, Brandon; Nagasaki, Keizo; Tomaru, Yuji; Wepf, Roger; Roseman, Alan; Varsani, Arvind; Sewell, Trevor

    2011-08-01

    Heterocapsa circularisquama RNA virus is a non-enveloped icosahedral ssRNA virus infectious to the harmful bloom-forming dinoflagellate, H. circularisquama, and which is assumed to be the major natural agent controlling the host population. The viral capsid is constructed from a single gene product. Electron cryo-microscopy revealed that the virus has a diameter of 34 nm and T = 3 symmetry. The 180 quasi-equivalent monomers have an unusual arrangement in that each monomer contributes to a 'bump' on the surface of the protein. Though the capsid protein probably has the classic 'jelly roll' β-sandwich fold, this is a new packing arrangement and is distantly related to the other positive-sense ssRNA virus capsid proteins. The handedness of the structure has been determined by a novel method involving high resolution scanning electron microscopy of the negatively stained viruses and secondary electron detection.

  14. In-situ Liquid Electron Microscopy Setups for Investigation of Nanoscale Electrochemistry

    DEFF Research Database (Denmark)

    Jensen, Eric; Møller-Nilsen, Rolf Erling Robberstad; Canepa, Silvia

    2014-01-01

    Recently there has been an explosion in the number of systems available for in-situliquid-phase electron microscopy (1). These systems separate the liquid from the vacuum andallow for nanoscale imaging as well as electrical contact. Such systems are important for the further development of nanoto......Recently there has been an explosion in the number of systems available for in-situliquid-phase electron microscopy (1). These systems separate the liquid from the vacuum andallow for nanoscale imaging as well as electrical contact. Such systems are important for the further development...... imaging. Currentmanufacturing will include lower liquid volume and electrical contact.The second system is a peek holder with a microfabricated chip which allows for fullelectrochemical characterization in the Scanning Electron Microscope (3) (Figure 1b). The system has been used for in...

  15. A Survey of the Use of Iterative Reconstruction Algorithms in Electron Microscopy

    Directory of Open Access Journals (Sweden)

    C. O. S. Sorzano

    2017-01-01

    Full Text Available One of the key steps in Electron Microscopy is the tomographic reconstruction of a three-dimensional (3D map of the specimen being studied from a set of two-dimensional (2D projections acquired at the microscope. This tomographic reconstruction may be performed with different reconstruction algorithms that can be grouped into several large families: direct Fourier inversion methods, back-projection methods, Radon methods, or iterative algorithms. In this review, we focus on the latter family of algorithms, explaining the mathematical rationale behind the different algorithms in this family as they have been introduced in the field of Electron Microscopy. We cover their use in Single Particle Analysis (SPA as well as in Electron Tomography (ET.

  16. Dynamic tunneling force microscopy for characterizing electronic trap states in non-conductive surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Wang, R.; Williams, C. C., E-mail: clayton@physics.utah.edu [Department of Physics and Astronomy, University of Utah, Salt Lake City, Utah 84112 (United States)

    2015-09-15

    Dynamic tunneling force microscopy (DTFM) is a scanning probe technique for real space mapping and characterization of individual electronic trap states in non-conductive films with atomic scale spatial resolution. The method is based upon the quantum mechanical tunneling of a single electron back and forth between a metallic atomic force microscopy tip and individual trap states in completely non-conducting surface. This single electron shuttling is measured by detecting the electrostatic force induced on the probe tip at the shuttling frequency. In this paper, the physical basis for the DTFM method is unfolded through a physical model and a derivation of the dynamic tunneling signal as a function of several experimental parameters is shown. Experimental data are compared with the theoretical simulations, showing quantitative consistency and verifying the physical model used. The experimental system is described and representative imaging results are shown.

  17. Analytical Electron Microscopy for Characterization of Fluid or Semi-Solid Multiphase Systems Containing Nanoparticulate Material

    Directory of Open Access Journals (Sweden)

    Nadejda B. Matsko

    2013-02-01

    Full Text Available The analysis of nanomaterials in pharmaceutical or cosmetic preparations is an important aspect both in formulation development and quality control of marketed products. Despite the increased popularity of nanoparticulate compounds especially in dermal preparations such as emulsions, methods and protocols of analysis for the characterization of such systems are scarce. This work combines an original sample preparation procedure along with different methods of analytical electron microscopy for the comprehensive analysis of fluid or semi-solid dermal preparations containing nanoparticulate material. Energy-filtered transmission electron microscopy, energy-dispersive X-ray spectroscopy, electron energy loss spectroscopy and high resolution imaging were performed on model emulsions and a marketed product to reveal different structural aspects of both the emulsion bulk phase and incorporated nanosized material. An innovative analytical approach for the determination of the physical stability of the emulsion under investigation is presented. Advantages and limitations of the employed analytical imaging techniques are highlighted.

  18. Characterization of III-V nanowires for photovoltaic devices using advanced electron microscopy techniques

    DEFF Research Database (Denmark)

    Persson, Johan Mikael

    In this work, the crystal structure of epitaxially grown semiconductor nanowires has been analysed using electron microscopy and to some extent X-ray diffractometry. The goal of the EU project which this work was a part of was to build multi-junction solar cells with nanowires as the main building...... to examine the very same nanowire sample using both X-ray diffraction and transmission electron microscopy. The examined structures were probed for their relative tilt to the substrate. Nanobeam electron diffraction was used in order to probe the local crystal structure of a nanowire, especially across...... of the crystal structure at the junction. This thesis also comments on some unusual properties and _ndings of the examined nanowires: Some nanowires sported a droplet-like protrusion of the catalyst gold particle reaching into the solid center of the nanowire. This feature can be discussed in terms of nanowire...

  19. Corneal collagen cross-linking: a confocal, electron, and light microscopy study of eye bank corneas.

    Science.gov (United States)

    Dhaliwal, Jasmeet S; Kaufman, Stephen C

    2009-01-01

    The purpose of this study was to evaluate morphological changes induced by corneal collagen cross-linking in a human ex vivo cornea, using confocal, electron, and light microscopy. The central epithelium was partially removed from ex vivo human corneal buttons. Riboflavin 0.1% solution was applied before ultraviolet A light treatment and then for every 2 minutes for 30 minutes while the corneas were exposed to ultraviolet A light at a wavelength of 370 nm and intensity of 3 mW/cm(2). Each cornea was evaluated using confocal, electron, and light microscopy. Confocal microscopy demonstrated normal-appearing corneas on their initial pretreatment examination, with reduced stromal detail. After treatment, a superficial layer of highly reflective spherical structures (4-10 microm) was observed. Many of these hyperreflective structures appeared up to a depth of 300 microm. The remainder of the corneal stroma and endothelium appeared normal. Electron microscopy showed keratocyte apoptotic changes to a depth of 300 microm. No observable pathologic changes were seen on histology. Based on clinical studies, corneal cross-linking is a promising treatment that appears to be safe and to halt ectatic corneal disease progression. Initial European studies used animal models to extrapolate human protocols. In conjunction with clinical studies, we believe that human ex vivo corneal studies provide a means to evaluate the structural and morphological changes associated with this procedure, within human corneas, in a manner that cannot be accomplished in vivo.

  20. Imaging transient blood vessel fusion events in zebrafish by correlative volume electron microscopy.

    Directory of Open Access Journals (Sweden)

    Hannah E J Armer

    Full Text Available The study of biological processes has become increasingly reliant on obtaining high-resolution spatial and temporal data through imaging techniques. As researchers demand molecular resolution of cellular events in the context of whole organisms, correlation of non-invasive live-organism imaging with electron microscopy in complex three-dimensional samples becomes critical. The developing blood vessels of vertebrates form a highly complex network which cannot be imaged at high resolution using traditional methods. Here we show that the point of fusion between growing blood vessels of transgenic zebrafish, identified in live confocal microscopy, can subsequently be traced through the structure of the organism using Focused Ion Beam/Scanning Electron Microscopy (FIB/SEM and Serial Block Face/Scanning Electron Microscopy (SBF/SEM. The resulting data give unprecedented microanatomical detail of the zebrafish and, for the first time, allow visualization of the ultrastructure of a time-limited biological event within the context of a whole organism.

  1. Characterization of fast photoelectron packets in weak and strong laser fields in ultrafast electron microscopy.

    Science.gov (United States)

    Plemmons, Dayne A; Tae Park, Sang; Zewail, Ahmed H; Flannigan, David J

    2014-11-01

    The development of ultrafast electron microscopy (UEM) and variants thereof (e.g., photon-induced near-field electron microscopy, PINEM) has made it possible to image atomic-scale dynamics on the femtosecond timescale. Accessing the femtosecond regime with UEM currently relies on the generation of photoelectrons with an ultrafast laser pulse and operation in a stroboscopic pump-probe fashion. With this approach, temporal resolution is limited mainly by the durations of the pump laser pulse and probe electron packet. The ability to accurately determine the duration of the electron packets, and thus the instrument response function, is critically important for interpretation of dynamics occurring near the temporal resolution limit, in addition to quantifying the effects of the imaging mode. Here, we describe a technique for in situ characterization of ultrashort electron packets that makes use of coupling with photons in the evanescent near-field of the specimen. We show that within the weakly-interacting (i.e., low laser fluence) regime, the zero-loss peak temporal cross-section is precisely the convolution of electron packet and photon pulse profiles. Beyond this regime, we outline the effects of non-linear processes and show that temporal cross-sections of high-order peaks explicitly reveal the electron packet profile, while use of the zero-loss peak becomes increasingly unreliable. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. Analysis of enamel microbiopsies in shed primary teeth by Scanning Electron Microscopy (SEM) and Polarizing Microscopy (PM)

    Energy Technology Data Exchange (ETDEWEB)

    Costa de Almeida, Glauce Regina; Molina, Gabriela Ferian; Meschiari, Cesar Arruda [Department of Morphology, Stomatology and Physiology, Dental School of Ribeirao Preto, University of Sao Paulo - FORP/USP, Av. do Cafe, S/N, Monte Alegre, CEP 14040-904, Ribeirao Preto, SP (Brazil); Barbosa de Sousa, Frederico [Department of Morphology, Dental School of Joao Pessoa, Federal University of Paraiba - UFPB, Av Castelo Branco - Campus I, CEP 58.059-900, Joao Pessoa, PB (Brazil); Gerlach, Raquel Fernanda, E-mail: rfgerlach@forp.usp.br [Department of Morphology, Stomatology and Physiology, Dental School of Ribeirao Preto, University of Sao Paulo - FORP/USP, Av. do Cafe, S/N, Monte Alegre, CEP 14040-904, Ribeirao Preto, SP (Brazil)

    2009-09-01

    The aims of this study were 1) to verify how close to the theoretically presumed areas are the areas of enamel microbiopsies carried out in vivo or in exfoliated teeth; 2) to test whether the etching solution penetrates beyond the tape borders; 3) to test whether the etching solution demineralizes the enamel in depth. 24 shed upper primary central incisors were randomly divided into two groups: the Rehydrated Teeth Group and the Dry Teeth Group. An enamel microbiopsy was performed, and the enamel microbiopsies were then analyzed by Scanning Electron Microscopy (SEM) and Polarizing Microscopy (PM). Quantitative birefringence measurements were performed. The 'true' etched area was determined by measuring the etched enamel using the NIH Image analysis program. Enamel birefringence was compared using the paired t test. There was a statistically significant difference when the etched areas in the Rehydrated teeth were compared with those of the Dry teeth (p = 0.04). The etched areas varied from - 11.6% to 73.5% of the presumed area in the Rehydrated teeth, and from 6.6% to 61.3% in the Dry teeth. The mean percentage of variation in each group could be used as a correction factor for the etched area. Analysis of PM pictures shows no evidence of in-depth enamel demineralization by the etching solution. No statistically significant differences in enamel birefringence were observed between values underneath and outside the microbiopsy area in the same tooth, showing that no mineral loss occurred below the enamel superficial layer. Our data showed no evidence of in-depth enamel demineralization by the etching solution used in the enamel microbiopsy proposed for primary enamel. This study also showed a variation in the measured diameter of the enamel microbiopsy in nineteen teeth out of twenty four, indicating that in most cases the etching solution penetrated beyond the tape borders.

  3. Robert Feulgen Prize Lecture 1995. Electronic light microscopy: present capabilities and future prospects.

    Science.gov (United States)

    Shotton, D M

    1995-08-01

    Electronic light microscopy involves the combination of microscopic techniques with electronic imaging and digital image processing, resulting in dramatic improvements in image quality and ease of quantitative analysis. In this review, after a brief definition of digital images and a discussion of the sampling requirements for the accurate digital recording of optical images, I discuss the three most important imaging modalities in electronic light microscopy--video-enhanced contrast microscopy, digital fluorescence microscopy and confocal scanning microscopy--considering their capabilities, their applications, and recent developments that will increase their potential. Video-enhanced contrast microscopy permits the clear visualisation and real-time dynamic recording of minute objects such as microtubules, vesicles and colloidal gold particles, an order of magnitude smaller than the resolution limit of the light microscope. It has revolutionised the study of cellular motility, and permits the quantitative tracking of organelles and gold-labelled membrane bound proteins. In combination with the technique of optical trapping (optical tweezers), it permits exquisitely sensitive force and distance measurements to be made on motor proteins. Digital fluorescence microscopy enables low-light-level imaging of fluorescently labelled specimens. Recent progress has involved improvements in cameras, fluorescent probes and fluorescent filter sets, particularly multiple bandpass dichroic mirrors, and developments in multiparameter imaging, which is becoming particularly important for in situ hybridisation studies and automated image cytometry, fluorescence ratio imaging, and time-resolved fluorescence. As software improves and small computers become more powerful, computational techniques for out-of-focus blur deconvolution and image restoration are becoming increasingly important. Confocal microscopy permits convenient, high-resolution, non-invasive, blur-free optical

  4. Imaging metazoan nuclear pore complexes by field emission scanning electron microscopy.

    Science.gov (United States)

    Fichtman, Boris; Shaulov, Lihi; Harel, Amnon

    2014-01-01

    High resolution three-dimensional surface images of nuclear pore complexes (NPCs) can be obtained by field emission scanning electron microscopy. We present a short retrospective view starting from the early roots of microscopy, through the discovery of the cell nucleus and the development of some modern techniques for sample preparation and imaging. Detailed protocols are presented for assembling anchored nuclei in a Xenopus cell-free reconstitution system and for the exposure of the nuclear surface in mammalian cell nuclei. Immunogold labeling of metazoan NPCs and a promising new technique for delicate coating with iridium are also discussed. Copyright © 2014 Elsevier Inc. All rights reserved.

  5. Note on in situ (scanning) transmission electron microscopy study of liquid samples.

    Science.gov (United States)

    Jiang, Nan

    2017-08-01

    Liquid cell (scanning) transmission electron microscopy has been developed rapidly, using amorphous SiNx membranes as electron transparent windows. The current interpretations of electron beam effects are mainly based on radiolytic processes. In this note, additional effects of the electric field due to electron-beam irradiation are discussed. The electric field can be produced by the charge accumulation due to the emission of secondary and Auger electrons. Besides various beam-induced phenomena, such as nanoparticle precipitation and gas bubble formation and motion, two other effects need to be considered; one is the change of Gibbs free energy of nucleation and the other is the violation of Brownian motion due to ion drifting driven by the electric field. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Beam spot diameter of the near-field scanning electron microscopy.

    Science.gov (United States)

    Kyritsakis, A; Xanthakis, J P

    2013-02-01

    We have examined the beam spot diameter at the anode of the scanning electron microscopy (SEM) in the near-field mode as a function of the anode-tip distance d. The detector lateral resolution of this type of microscopy is approximately equal to this spot diameter. For our calculations we have simulated the apex region of the tip with an ellipsoid of revolution of radii R₁ and R₂ with R₁>R₂ as suggested by TEM images of the realistic tips. We have then solved the Laplace equation to obtain the electrostatic potential and to this we have added a spherical image potential. The calculated electrostatic field is highly asymmetric, being strong along the tip-axis and weakening quickly towards the sides. When a 3-dimensional WKB approximation is used to calculate the electron paths corresponding to such a potential, the latter are shown to bend significantly towards the vertical (tip-axis) direction producing a beam narrowing effect very similar to the beam narrowing effect we discovered for the traditional SEM case. When the values of R₁, R₂ are chosen from fittings to the TEM images of the tips used in the experiments, the beam spot diameter W at the anode (d=25 nm) varies from 12.5 nm to 9 nm depending on the fitted R₁, R₂. These values of W are considerably smaller than previously predicted by calculating solid angles of emission from spherical surfaces (41 nm) but also much closer to the detector lateral resolution (6-7 nm) obtained from differentiating the experimental current step. This trend continued at all other d examined. Furthermore the beam width W was found to decrease quickly with increasing sharpness S=R₁/R₂ of the tip and then saturate. W is also decreasing with decreasing R₁, R₂ with S kept constant. We deduce that the sharpness of the tip is important not only for creating high extraction fields but also for guaranteeing a very small beam spot diameter. Copyright © 2012 Elsevier B.V. All rights reserved.

  7. Indirect Immunodetection of Fungal Fragments by Field Emission Scanning Electron Microscopy.

    Science.gov (United States)

    Afanou, Komlavi Anani; Straumfors, Anne; Skogstad, Asbjørn; Nayak, Ajay P; Skaar, Ida; Hjeljord, Linda; Tronsmo, Arne; Eduard, Wijnand; Green, Brett James

    2015-09-01

    Submicronic fungal fragments have been observed in in vitro aerosolization experiments. The occurrence of these particles has therefore been suggested to contribute to respiratory health problems observed in mold-contaminated indoor environments. However, the role of submicronic fragments in exacerbating adverse health effects has remained unclear due to limitations associated with detection methods. In the present study, we report the development of an indirect immunodetection assay that utilizes chicken polyclonal antibodies developed against spores from Aspergillus versicolor and high-resolution field emission scanning electron microscopy (FESEM). Immunolabeling was performed with A. versicolor fragments immobilized and fixed onto poly-l-lysine-coated polycarbonate filters. Ninety percent of submicronic fragments and 1- to 2-μm fragments, compared to 100% of >2-μm fragments generated from pure freeze-dried mycelial fragments of A. versicolor, were positively labeled. In proof-of-concept experiments, air samples collected from moldy indoor environments were evaluated using the immunolabeling technique. Our results indicated that 13% of the total collected particles were derived from fungi. This fraction comprises 79% of the fragments that were detected by immunolabeling and 21% of the spore particles that were morphologically identified. The methods reported in this study enable the enumeration of fungal particles, including submicronic fragments, in a complex heterogeneous environmental sample. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  8. eV-TEM: Transmission electron microscopy in a low energy cathode lens instrument

    Energy Technology Data Exchange (ETDEWEB)

    Geelen, Daniël, E-mail: geelen@physics.leidenuniv.nl [Huygens-Kamerlingh Onnes Laboratory, Leiden Institute of Physics, Leiden University, P.O. Box 9504, 2300 RA Leiden (Netherlands); Thete, Aniket [Huygens-Kamerlingh Onnes Laboratory, Leiden Institute of Physics, Leiden University, P.O. Box 9504, 2300 RA Leiden (Netherlands); Schaff, Oliver; Kaiser, Alexander [SPECS GmbH, Voltastrasse 5, D-13355 Berlin (Germany); Molen, Sense Jan van der [Huygens-Kamerlingh Onnes Laboratory, Leiden Institute of Physics, Leiden University, P.O. Box 9504, 2300 RA Leiden (Netherlands); Tromp, Rudolf [IBM T.J. Watson Research Center, 1101 Kitchawan Road, P.O. Box 218, Yorktown Heights, NY 10598 (United States)

    2015-12-15

    We are developing a transmission electron microscope that operates at extremely low electron energies, 0–40 eV. We call this technique eV-TEM. Its feasibility is based on the fact that at very low electron energies the number of energy loss pathways decreases. Hence, the electron inelastic mean free path increases dramatically. eV-TEM will enable us to study elastic and inelastic interactions of electrons with thin samples. With the recent development of aberration correction in cathode lens instruments, a spatial resolution of a few nm appears within range, even for these very low electron energies. Such resolution will be highly relevant to study biological samples such as proteins and cell membranes. The low electron energies minimize adverse effects due to radiation damage. - Highlights: • We present a new way of performing low energy transmission electron microscopy in an aberration corrected LEEM/PEEM instrument. • We show a proof of principle where we measure transmitted electrons through a suspended graphene monolayer with a preliminary setup. • We present an improved setup design that provides better control of the incident electron beam.

  9. Human Islet Amyloid Polypeptide Fibril Binding to Catalase: A Transmission Electron Microscopy and Microplate Study

    Directory of Open Access Journals (Sweden)

    Nathaniel G. N. Milton

    2010-01-01

    Full Text Available The diabetes-associated human islet amyloid polypeptide (IAPP is a 37-amino-acid peptide that forms fibrils in vitro and in vivo. Human IAPP fibrils are toxic in a similar manner to Alzheimer's amyloid-β (Aβ and prion protein (PrP fibrils. Previous studies have shown that catalase binds to Aβ fibrils and appears to recognize a region containing the Gly-Ala-Ile-Ile sequence that is similar to the Gly-Ala-Ile-Leu sequence found in human IAPP residues 24-27. This study presents a transmission electron microscopy (TEM—based analysis of fibril formation and the binding of human erythrocyte catalase to IAPP fibrils. The results show that human IAPP 1-37, 8-37, and 20-29 peptides form fibrils with diverse and polymorphic structures. All three forms of IAPP bound catalase, and complexes of IAPP 1-37 or 8-37 with catalase were identified by immunoassay. The binding of biotinylated IAPP to catalase was high affinity with a KD of 0.77nM, and could be inhibited by either human or rat IAPP 1-37 and 8-37 forms. Fibrils formed by the PrP 118-135 peptide with a Gly-Ala-Val-Val sequence also bound catalase. These results suggest that catalase recognizes a Gly-Ala-Ile-Leu—like sequence in amyloid fibril-forming peptides. For IAPP 1-37 and 8-37, the catalase binding was primarily directed towards fibrillar rather than ribbon-like structures, suggesting differences in the accessibility of the human IAPP 24-27 Gly-Ala-Ile-Leu region. This suggests that catalase may be able to discriminate between different structural forms of IAPP fibrils. The ability of catalase to bind IAPP, Aβ, and PrP fibrils demonstrates the presence of similar accessible structural motifs that may be targets for antiamyloid therapeutic development.

  10. Single-Cell Resolution of Uncultured Magnetotactic Bacteria via Fluorescence-Coupled Electron Microscopy.

    Science.gov (United States)

    Li, Jinhua; Zhang, Heng; Menguy, Nicolas; Benzerara, Karim; Wang, Fuxian; Lin, Xiaoting; Chen, Zhibao; Pan, Yongxin

    2017-06-15

    Magnetotactic bacteria (MTB) form intracellular chain-assembled nanocrystals of magnetite or greigite termed magnetosomes. The characterization of magnetosome crystals requires electron microscopy due to their nanoscopic sizes. However, electron microscopy does not provide phylogenetic information for MTB. We have developed a strategy for the simultaneous and rapid phylogenetic and biomineralogical characterization of uncultured MTB at the single-cell level. It consists of four steps: (i) enrichment of MTB cells from an environmental sample, (ii) 16S rRNA gene sequencing of MTB, and (iii) fluorescence in situ hybridization analyses coordinated with (iv) transmission or scanning electron microscopy of the probe-hybridized cells. The application of this strategy identified a magnetotactic Gammaproteobacteria strain, SHHR-1, from brackish sediments collected from the Shihe River estuary in Qinhuangdao City, China. SHHR-1 magnetosomes are elongated prismatic magnetites which can be idealized as hexagonal prisms. Taxonomic groups of uncultured MTB were also identified in freshwater sediments from Lake Miyun in northern Beijing via this novel coordinated fluorescence and scanning electron microscopy method based on four group-specific rRNA-targeted probes. Our analyses revealed that major magnetotactic taxonomic groups can be accurately determined only with coordinated scanning electron microscopy observations on fluorescently labeled single cells due to limited group coverage and specificity for existing group-specific MTB fluorescence in situ hybridization (FISH) probes. Our reported strategy is simple and efficient, offers great promise toward investigating the diversity and biomineralization of MTB, and may also be applied to other functional groups of microorganisms.IMPORTANCE Magnetotactic bacteria (MTB) are phylogenetically diverse and biomineralize morphologically diverse magnetic nanocrystals of magnetite or greigite in intracellular structures termed

  11. Specimen preparation by ion beam slope cutting for characterization of ductile damage by scanning electron microscopy.

    Science.gov (United States)

    Besserer, Hans-Bernward; Gerstein, Gregory; Maier, Hans Jürgen; Nürnberger, Florian

    2016-04-01

    To investigate ductile damage in parts made by cold sheet-bulk metal forming a suited specimen preparation is required to observe the microstructure and defects such as voids by electron microscopy. By means of ion beam slope cutting both a targeted material removal can be applied and mechanical or thermal influences during preparation avoided. In combination with scanning electron microscopy this method allows to examine voids in the submicron range and thus to analyze early stages of ductile damage. In addition, a relief structure is formed by the selectivity of the ion bombardment, which depends on grain orientation and microstructural defects. The formation of these relief structures is studied using scanning electron microscopy and electron backscatter diffraction and the use of this side effect to interpret the microstructural mechanisms of voids formation by plastic deformation is discussed. A comprehensive investigation of the suitability of ion beam milling to analyze ductile damage is given at the examples of a ferritic deep drawing steel and a dual phase steel. © 2016 Wiley Periodicals, Inc.

  12. Ultrastructural analysis of testicular tissue and sperm by transmission and scanning electron microscopy.

    Science.gov (United States)

    Chemes, Hector E

    2013-01-01

    Transmission electron microscopy (TEM) studies have provided the basis for an in-depth understanding of the cell biology and normal functioning of the testis and male gametes and have opened the way to characterize the functional role played by specific organelles in spermatogenesis and sperm function. The development of the scanning electron microscope (SEM) extended these boundaries to the recognition of cell and organ surface features and the architectural array of cells and tissues. The merging of immunocytochemical and histochemical approaches with electron microscopy has completed a series of technical improvements that integrate structural and functional features to provide a broad understanding of cell biology in health and disease. With these advances the detailed study of the intricate structural and molecular organization as well as the chemical composition of cellular organelles is now possible. Immunocytochemistry is used to identify proteins or other components and localize them in specific cells or organelles with high specificity and sensitivity, and histochemistry can be used to understand their function (i.e., enzyme activity). When these techniques are used in conjunction with electron microscopy their resolving power is further increased to subcellular levels. In the present chapter we will describe in detail various ultrastructural techniques that are now available for basic or translational research in reproductive biology and reproductive medicine. These include TEM, ultrastructural immunocytochemistry, ultrastructural histochemistry, and SEM.

  13. Three-dimensional imaging of cerebellar mossy fiber rosettes by ion-abrasion scanning electron microscopy.

    Science.gov (United States)

    Kim, Hyun-Wook; Kim, Namkug; Kim, Ki Woo; Rhyu, Im Joo

    2013-08-01

    The detailed knowledge of the three-dimensional (3D) organization of the nervous tissue provides essential information on its functional elucidation. We used serial block-face scanning electron microscopy with focused ion beam (FIB) milling to reveal 3D morphologies of the mossy fiber rosettes in the mice cerebellum. Three-week-old C57 black mice were perfused with a fixative of 1% paraformaldehyde/1% glutaraldehyde in phosphate buffer; the cerebellum was osmicated and embedded in the Araldite. The block containing granule cell layer was sliced with FIB and observed by field-emission scanning electron microscopy. The contrast of backscattered electron image of the block-face was similar to that of transmission electron microscopy and processed using 3D visualization software for further analysis. The mossy fiber rosettes on each image were segmented and rendered to visualize the 3D model. The complete 3D characters of the mossy fiber rosette could be browsed on the A-Works, in-house software, and some preliminary quantitative data on synapse of the rosette could be extracted from these models. Thanks to the development of two-beam imaging and optimized software, we could get 3D information on cerebellar mossy fiber rosettes with ease and speedily, which would be an additive choice to explore 3D structures of the nervous systems and their networks.

  14. Combined Use of Electron and Light Microscopy Techniques Reveals False Secondary Shell Units in Megaloolithidae Eggshells.

    Science.gov (United States)

    Moreno-Azanza, Miguel; Bauluz, Blanca; Canudo, José Ignacio; Gasca, José Manuel; Torcida Fernández-Baldor, Fidel

    2016-01-01

    Abnormalities in the histo- and ultrastructure of the amniote eggshell are often related to diverse factors, such as ambient stress during egg formation, pathologies altering the physiology of the egg-laying females, or evolutionarily selected modifications of the eggshell structure that vary the physical properties of the egg, for example increasing its strength so as to avoid fracture during incubation. When dealing with fossil materials, all the above hypotheses are plausible, but a detailed taphonomical study has to be performed to rule out the possibility that secondary processes of recrystallization have occurred during fossilization. Traditional analyses, such as optical microscopy inspection and cathodoluminescence, have proven not to be enough to understand the taphonomic story of some eggshells. Recently, electron backscatter diffraction has been used, in combination with other techniques, to better understand the alteration of fossil eggshells. Here we present a combined study using scanning electron microscopy, optical microscopy, cathodoluminescence and electron backscatter diffraction of eggshell fragments assigned to Megaloolithus cf. siruguei from the Upper Cretaceous outcrops of the Cameros Basin. We focus our study on the presence of secondary shell units that mimic most aspects of the ultrastructure of the eggshell mammillae, but grow far from the inner surface of the eggshell. We call these structures extra-spherulites, describe their crystal structure and demonstrate their secondary origin. Our study has important implications for the interpretation of secondary shell units as biological or pathological structures. Thus, electron backscatter diffraction complements other microscope techniques as a useful tool for understanding taphonomical alterations in fossil eggshells.

  15. Electron microscopy studies of natural and synthetic zeolites impregnated with uranyl dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Acosta, Dwight R.; T-Olguin, Maria; Solache, Marcos; Bosch, Pedro; Bulbulian, Silvia [Universidad Nacional Autonoma de Mexico, Mexico City (Mexico). Inst. de Fisica; Asomoza, Max [Instituto Nacional de Investigaciones Nucleares, Mexico City (Mexico). Dept. de Quimica Nuclear

    1995-09-01

    Full text. The use of Y zeolite and erionite to remove uranyl dioxide ions from aqueous solution is focussed on catalysis and energy transfer problems but it can be oriented to recovery uranyl dioxide ions, among other radioactive compounds. The samples impregnated with uranyl dioxide at several concentrations and contact times were studied using conventional, high resolution and scanning electron microscopy in order to detect changes as consequence of contact with a radioactive material and to verify mechanical stability of zeolites. Also X ray diffraction, thermal analysis, neutron activation were used to characterize the samples at several steps of treatment. The crystallinity of zeolites was maintained only when using dilute uranyl nitrate solution (up to 0.0100 N for y zeolite and 0.0300 N for erionite). The samples impregnated with highest nitrate concentrations partially lost their crystallinity. From selected area electron diffraction pattern, lattice parameter variations were detected and from high resolution electron microscopy localization of uranyl ions in and on zeolite structure was determined. Surface modification in zeolites was observed by scanning electron microscopy just for samples with long contact time with radioactive solutions. (author)

  16. Weak-beam scanning transmission electron microscopy for quantitative dislocation density measurement in steels.

    Science.gov (United States)

    Yoshida, Kenta; Shimodaira, Masaki; Toyama, Takeshi; Shimizu, Yasuo; Inoue, Koji; Yoshiie, Toshimasa; Milan, Konstantinovic J; Gerard, Robert; Nagai, Yasuyoshi

    2017-04-01

    To evaluate dislocations induced by neutron irradiation, we developed a weak-beam scanning transmission electron microscopy (WB-STEM) system by installing a novel beam selector, an annular detector, a high-speed CCD camera and an imaging filter in the camera chamber of a spherical aberration-corrected transmission electron microscope. The capabilities of the WB-STEM with respect to wide-view imaging, real-time diffraction monitoring and multi-contrast imaging are demonstrated using typical reactor pressure vessel steel that had been used in an European nuclear reactor for 30 years as a surveillance test piece with a fluence of 1.09 × 1020 neutrons cm-2. The quantitatively measured size distribution (average loop size = 3.6 ± 2.1 nm), number density of the dislocation loops (3.6 × 1022 m-3) and dislocation density (7.8 × 1013 m m-3) were carefully compared with the values obtained via conventional weak-beam transmission electron microscopy studies. In addition, cluster analysis using atom probe tomography (APT) further demonstrated the potential of the WB-STEM for correlative electron tomography/APT experiments. © The Author 2017. 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.

  17. External morphogenesis of the tardigrade Hypsibius dujardini as revealed by scanning electron microscopy.

    Science.gov (United States)

    Gross, Vladimir; Minich, Irene; Mayer, Georg

    2017-04-01

    Tardigrada, commonly called water bears, is a taxon of microscopic panarthropods with five-segmented bodies and four pairs of walking legs. Although tardigrades have been known to science for several centuries, questions remain regarding many aspects of their biology, such as embryogenesis. Herein, we used scanning electron microscopy to document the external changes that occur during embryonic development in the tardigrade Hypsibius dujardini (Eutardigrada, Parachela, Hypsibiidae). Our results show an accelerated development of external features, with approximately 30 hrs separating the point at which external structures first become recognizable and a fully formed embryo. All segments appear to arise simultaneously between ∼20 and 25 hrs of development, and no differences in the degree of development could be detected between the limb buds at any stage. Claws emerge shortly after the limb buds and are morphologically similar to those of adults. The origin of the claws is concurrent with that of the sclerotized parts of the mouth, suggesting that all cuticular structures arise simultaneously at ∼30 hrs. The mouth arises as an invagination in the terminal region of the head at ∼25 hrs, closes later in development, and opens again shortly before hatching. The anlagen of the peribuccal lobes arise as one dorsal and one ventral row, each consisting of three lobes, and later form a ring in the late embryo, whereas there is no indication of a labrum anlage at any point during development. Furthermore, we describe limited postembryonic development in the form of cuticular pores that are absent in juveniles but present in adults. This study represents the first scanning electron micrographs of tardigrade embryos, demonstrating the utility of this technique for studying embryogenesis in tardigrades. This work further adds an external morphological perspective to the developmental data already available for H. dujardini, facilitating future comparisons to related

  18. Rapid imaging of mycoplasma in solution using Atmospheric Scanning Electron Microscopy (ASEM)

    Energy Technology Data Exchange (ETDEWEB)

    Sato, Chikara, E-mail: ti-sato@aist.go.jp [Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, Ibaraki 305-8566 (Japan); Manaka, Sachie [Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, Ibaraki 305-8566 (Japan); Nakane, Daisuke [Department of Biology, Graduate School of Science, Osaka City University, Sumiyoshi-ku, Osaka 558-8585 (Japan); Nishiyama, Hidetoshi; Suga, Mitsuo [Advanced Technology Division, JEOL Ltd., Akishima, Tokyo 196-8558 (Japan); Nishizaka, Takayuki [Department of Physics, Faculty of Science, Gakushuin University, 1-5-1 Mejiro, Toshima-ku, Tokyo 171-8588 (Japan); Miyata, Makoto [Department of Biology, Graduate School of Science, Osaka City University, Sumiyoshi-ku, Osaka 558-8585 (Japan); Maruyama, Yuusuke [Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, Ibaraki 305-8566 (Japan)

    2012-01-27

    Highlights: Black-Right-Pointing-Pointer Mycoplasma mobile was observed in buffer with the Atmospheric Scanning Electron Microscope. Black-Right-Pointing-Pointer Characteristic protein localizations were visualized using immuno-labeling. Black-Right-Pointing-Pointer M. mobile attached to sialic acid on the SiN film surface within minutes. Black-Right-Pointing-Pointer Cells were observed at low concentrations. Black-Right-Pointing-Pointer ASEM should promote study and early-stage diagnosis of mycoplasma. -- Abstract: Mycoplasma is a genus of bacterial pathogen that causes disease in vertebrates. In humans, the species Mycoplasma pneumoniae causes 15% or more of community-acquired pneumonia. Because this bacterium is tiny, corresponding in size to a large virus, diagnosis using optical microscopy is not easy. In current methods, chest X-rays are usually the first action, followed by serology, PCR amplification, and/or culture, but all of these are particularly difficult at an early stage of the disease. Using Mycoplasma mobile as a model species, we directly observed mycoplasma in buffer with the newly developed Atmospheric Scanning Electron Microscope (ASEM). This microscope features an open sample dish with a pressure-resistant thin film window in its base, through which the SEM beam scans samples in solution, from below. Because of its 2-3 {mu}m-deep scanning capability, it can observe the whole internal structure of mycoplasma cells stained with metal solutions. Characteristic protein localizations were visualized using immuno-labeling. Cells were observed at low concentrations, because suspended cells concentrate in the observable zone by attaching to sialic acid on the silicon nitride (SiN) film surface within minutes. These results suggest the applicability of the ASEM for the study of mycoplasmas as well as for early-stage mycoplasma infection diagnosis.

  19. Electron microscopy investigations of changes in morphology and conductivity of LiFePO4/C electrodes

    DEFF Research Database (Denmark)

    Scipioni, Roberto; Jørgensen, Peter S.; Ngo, Duc-The

    2016-01-01

    In this work we study the structural degradation of a laboratory Li-ion battery LiFePO4/Carbon Black (LFP/CB) cathode by various electron microscopy techniques including low kV Focused Ion Beam (FIB)/Scanning Electron Microscopy (SEM) 3D tomography. Several changes are observed in FIB/SEM images ...

  20. Comparative electron microscopy and image analysis of oxy- and deoxy-hemocyanin from the spiny lobster Panulirus interruptus

    NARCIS (Netherlands)

    Haas, Felix de; Breemen, Jan F.L. van; Boekema, Egbert J.; Keegstra, Wilko; Bruggen, Ernst F.J. van

    1993-01-01

    Structural differences between oxy-hemocyanin and deoxy-hemocyanin from the spiny lobster P. interruptus were studied by electron microscopy and image analysis of negatively stained preparations. Projections of the hexameric P. interruptus hemocyanin from electron microscopy were compared with

  1. Synergy between transmission electron microscopy and powder diffraction: application to modulated structures.

    Science.gov (United States)

    Batuk, Dmitry; Batuk, Maria; Abakumov, Artem M; Hadermann, Joke

    2015-04-01

    The crystal structure solution of modulated compounds is often very challenging, even using the well established methodology of single-crystal X-ray crystallography. This task becomes even more difficult for materials that cannot be prepared in a single-crystal form, so that only polycrystalline powders are available. This paper illustrates that the combined application of transmission electron microscopy (TEM) and powder diffraction is a possible solution to the problem. Using examples of anion-deficient perovskites modulated by periodic crystallographic shear planes, it is demonstrated what kind of local structural information can be obtained using various TEM techniques and how this information can be implemented in the crystal structure refinement against the powder diffraction data. The following TEM methods are discussed: electron diffraction (selected area electron diffraction, precession electron diffraction), imaging (conventional high-resolution TEM imaging, high-angle annular dark-field and annular bright-field scanning transmission electron microscopy) and state-of-the-art spectroscopic techniques (atomic resolution mapping using energy-dispersive X-ray analysis and electron energy loss spectroscopy).

  2. Borrelia-like organism in heart capillaries of patient with Lyme-disease seen by electron microscopy.

    Science.gov (United States)

    Lalosevic, Dusan; Lalosevic, Vesna; Stojsic-Milosavljevic, Anastazija; Stojsic, Djurica

    2010-12-03

    A case of a patient who developed an acute myocarditis due to Lyme disease is reported. An increased serum antibody titer to Borrelia burgdorferi suggested a diagnosis and in addition of basic clinical methods, endomyocardial biopsy performed and analyzed by transmission electron microscopy. The lumen of myocardial capillaries was founded mostly filled with detritus and fibrin precipitate, between them several bacterial fragments were identified. The electron-microscopic characteristics of the microorganisms in this specimen, revealing irregularly coiled appearance and consistent thickness of 0.2 μm, correspond to the spiral-like structure of Lyme disease borrelia. The presence of fibrin deposits on the capillary endothelium and necrosis of myocardiocytes, suggests that the cardiopathy in our patient was represent borrelia-mediated damage of the heart microcirculation. Copyright © 2008 Elsevier Ireland Ltd. All rights reserved.

  3. Applications of emerging transmission electron microscopy technology in PCD research and diagnosis.

    Science.gov (United States)

    Shoemark, Amelia

    2017-01-01

    Primary Ciliary Dyskinesia (PCD) is a heterogeneous genetic condition characterized by dysfunction of motile cilia. Patients suffer from chronic infection and inflammation of the upper and lower respiratory tract. Diagnosis of PCD is confirmed by identification of a hallmark defect of ciliary ultrastructure or by identification of biallelic pathogenic mutations in a known PCD gene. Since the first description of PCD in 1976, assessment of ciliary ultrastructure by transmission electron microscopy (TEM) has been central to diagnosis and research. Electron tomography is a technique whereby a series of transmission electron micrographs are collected at different angles and reconstructed into a single 3D model of a specimen. Electron tomography provides improved spatial information and resolution compared to a single micrograph. Research by electron tomography has revealed new insight into ciliary ultrastructure and consequently ciliary function at a molecular and cellular level. Gene discovery studies in PCD have utilized electron tomography to define the structural consequences of variants in cilia genes. Modern transmission electron microscopes capable of electron tomography are increasingly being installed in clinical laboratories. This presents the possibility for the use of tomography technique in a diagnostic setting. This review describes the electron tomography technique, the contribution tomography has made to the understanding of basic cilia structure and function and finally the potential of the technique for use in PCD diagnosis.

  4. Characterization and analysis of individual fly-ash particles from coal-fired power stations by a combination of optical microscopy, electron microscopy and quantitative electron microprobe analysis

    Science.gov (United States)

    Ramsden, A. R.; Shibaoka, M.

    Quantitative electron microprobe analysis has been used to determine the inorganic chemical composition of individual fly-ash particles previously categorized on the basis of properties recognizable by light and scanning electron microscopy. Seven categories may be recognized: (1) unfused detrital minerals (principally quartz), (2) irregular-spongy particles derived from partly-fused clay minerals, (3) vesicular colourless glass (in the form of irregular particles and cenospheres) derived from viscous melts, (4) solid glass (mostly in the form of spherical particles and sometimes pigmented) derived from fluid melts, (5) dendritic iron oxide particles (mostly spherical) containing variable amounts of glass matrix, (6) crystalline iron oxide particles (mostly spherical) containing minimal amounts of glass and (7) unburnt char particles. The use of computerized energy dispersive X-ray analysis on the electron microprobe enables an analysis for all the inorganic elements present in a particle to be carried out simultaneously in about 60s. The rapidity and comprehensive nature of the procedure makes it possible to determine the composition of a large number of individual fly-ash particles in a relatively short time and thereby characterize the types and compositions that comprise the population.

  5. Towards correlative super-resolution fluorescence and electron cryo-microscopy.

    Science.gov (United States)

    Wolff, Georg; Hagen, Christoph; Grünewald, Kay; Kaufmann, Rainer

    2016-09-01

    Correlative light and electron microscopy (CLEM) has become a powerful tool in life sciences. Particularly cryo-CLEM, the combination of fluorescence cryo-microscopy (cryo-FM) permitting for non-invasive specific multi-colour labelling, with electron cryo-microscopy (cryo-EM) providing the undisturbed structural context at a resolution down to the Ångstrom range, has enabled a broad range of new biological applications. Imaging rare structures or events in crowded environments, such as inside a cell, requires specific fluorescence-based information for guiding cryo-EM data acquisition and/or to verify the identity of the structure of interest. Furthermore, cryo-CLEM can provide information about the arrangement of specific proteins in the wider structural context of their native nano-environment. However, a major obstacle of cryo-CLEM currently hindering many biological applications is the large resolution gap between cryo-FM (typically in the range of ∼400 nm) and cryo-EM (single nanometre to the Ångstrom range). Very recently, first proof of concept experiments demonstrated the feasibility of super-resolution cryo-FM imaging and the correlation with cryo-EM. This opened the door towards super-resolution cryo-CLEM, and thus towards direct correlation of structural details from both imaging modalities. © 2016 Société Française des Microscopies and Société de Biologie Cellulaire de France. Published by John Wiley & Sons Ltd.

  6. Correlative Super-resolution and Electron Microscopy to Resolve Protein Localization in Zebrafish Retina.

    Science.gov (United States)

    Mateos, José M; Barmettler, Gery; Doehner, Jana; Ojeda Naharros, Irene; Guhl, Bruno; Neuhauss, Stephan C F; Kaech, Andres; Bachmann-Gagescu, Ruxandra; Ziegler, Urs

    2017-11-10

    We present a method to investigate the subcellular protein localization in the larval zebrafish retina by combining super-resolution light microscopy and scanning electron microscopy. The sub-diffraction limit resolution capabilities of super-resolution light microscopes allow improving the accuracy of the correlated data. Briefly, 110 nanometer thick cryo-sections are transferred to a silicon wafer and, after immunofluorescence staining, are imaged by super-resolution light microscopy. Subsequently, the sections are preserved in methylcellulose and platinum shadowed prior to imaging in a scanning electron microscope (SEM). The images from these two microscopy modalities are easily merged using tissue landmarks with open source software. Here we describe the adapted method for the larval zebrafish retina. However, this method is also applicable to other types of tissues and organisms. We demonstrate that the complementary information obtained by this correlation is able to resolve the expression of mitochondrial proteins in relation with the membranes and cristae of mitochondria as well as to other compartments of the cell.

  7. Electronic cigarettes in the USA: a summary of available toxicology data and suggestions for the future

    OpenAIRE

    Orr, Michael S

    2014-01-01

    Objective To review the available evidence evaluating the toxicological profiles of electronic cigarettes (e-cigarettes) in order to understand the potential impact of e-cigarettes on individual users and the public health. Methods Systematic literature searches were conducted between October 2012 and October 2013 using five electronic databases. Search terms such as ‘e-cigarettes’ and ‘electronic delivery devices’ were used to identify the toxicology information for e-cigarettes. Results As ...

  8. Field emission scanning electron microscopy of biofilm-growing bacteria involved in nosocomial infections.

    Science.gov (United States)

    Vuotto, Claudia; Donelli, Gianfranco

    2014-01-01

    Scanning electron microscopy (SEM) provides useful information on the shape, size, and localization within the biofilm of single bacteria as well as on the steps of biofilm formation process, on bacterial interactions, and on production of extracellular polymeric substances.When biofilms are constituted by microbial species involved in health care-associated infections, information provided by SEM can be fruitfully used not only for basic researches but also for diagnostic purposes.The protocols currently used in our laboratory for biofilm investigation by SEM are reported here. Particularly, the procedures to fix, dehydrate, and metalize in vitro-developed biofilms or ex vivo clinical specimens colonized by biofilm-growing microorganisms are described as well as the advantages of the observation of these samples by field emission scanning electron microscopy.

  9. Annular dark-field scanning transmission electron microscopy (ADF-STEM) tomography of polymer systems.

    Science.gov (United States)

    Lu, Kangbo; Sourty, Erwan; Loos, Joachim

    2010-08-01

    We have utilized bright-field conventional transmission electron microscopy tomography and annular dark-field scanning transmission electron microscopy (ADF-STEM) tomography to characterize a well-defined carbon black (CB)-filled polymer nanocomposite with known CB volume concentration. For both imaging methods, contrast can be generated between the CB and the surrounding polymer matrix. The involved contrast mechanisms, in particular for ADF-STEM, will be discussed in detail. The obtained volume reconstructions were analysed and the CB volume concentrations were carefully determined from the reconstructed data. For both imaging modes, the measured CB volume concentrations are substantially different and only quantification based on the ADF-STEM data revealed about the same value as the known CB loading. Moreover, when applying low-convergence angles for imaging ADF-STEM tomography, data can be obtained of micrometre-thick samples.

  10. Monolithic Chip System with a Microfluidic Channel for In Situ Electron Microscopy of Liquids

    DEFF Research Database (Denmark)

    Jensen, Eric; Burrows, Andrew; Mølhave, Kristian

    2014-01-01

    sandwiched microchips with thin membranes. We report on a new microfabricated chip system based on a monolithic design that enables membrane geometry on the scale of a few micrometers. The design is intended to reduce membrane deflection when the system is under pressure, a micro fluidic channel for improved...... flow geometry, and a better space angle for auxiliary detectors such as energy-dispersive X-ray spectroscopy. We explain the system design and fabrication and show the first successful TEM images of liquid samples in the chips.......Electron microscopy of enclosed liquid samples requires the thinnest possible membranes as enclosing windows as well as nanoscale liquid sample thickness to achieve the best possible resolution. Today liquid sample systems for transmission electron microscopy (TEM) are typically made from two...

  11. A graphene oxide-carbon nanotube grid for high-resolution transmission electron microscopy of nanomaterials.

    Science.gov (United States)

    Zhang, Lina; Zhang, Haoxu; Zhou, Ruifeng; Chen, Zhuo; Li, Qunqing; Fan, Shoushan; Ge, Guanglu; Liu, Renxiao; Jiang, Kaili

    2011-09-23

    A novel grid for use in transmission electron microscopy is developed. The supporting film of the grid is composed of thin graphene oxide films overlying a super-aligned carbon nanotube network. The composite film combines the advantages of graphene oxide and carbon nanotube networks and has the following properties: it is ultra-thin, it has a large flat and smooth effective supporting area with a homogeneous amorphous appearance, high stability, and good conductivity. The graphene oxide-carbon nanotube grid has a distinct advantage when characterizing the fine structure of a mass of nanomaterials over conventional amorphous carbon grids. Clear high-resolution transmission electron microscopy images of various nanomaterials are obtained easily using the new grids.

  12. Practical Experience with Hole-Free Phase Plates for Cryo Electron Microscopy.

    Science.gov (United States)

    Marko, Michael; Hsieh, Chyongere; Leith, Eric; Mastronarde, David; Motoki, Sohei

    2016-12-01

    Phase plate (PP) imaging has proven to be valuable in transmission cryo electron microscopy of unstained, native-state biological specimens. Many PP types have been described, however until the recent implementation of the "hole-free" phase plate (HFPP), imaging has been challenging. We found the HFPP to be simple to construct and to set up in the transmission electron microscopy, but care in implementing automated data collection is needed. Performance may be variable, both initially and over time, thus it is important to monitor and evaluate image quality by observing the power spectrum. We found that while some HFPPs gave transfer to high resolution without CTF oscillation, most reached high resolution when operated with modest defocus.

  13. A nanocrystalline Hilbert phase-plate for phase-contrast transmission electron microscopy.

    Science.gov (United States)

    Dries, M; Hettler, S; Gamm, B; Müller, E; Send, W; Müller, K; Rosenauer, A; Gerthsen, D

    2014-04-01

    Thin-film-based phase-plates are applied to enhance the contrast of weak-phase objects in transmission electron microscopy. In this work, metal-film-based phase-plates are considered to reduce contamination and electrostatic charging, which up to now limit the application of phase-plates fabricated from amorphous C-films. Their crystalline structure requires a model for the simulation of the effect of crystallinity on the phase-plate properties and the image formation process. The model established in this work is verified by experimental results obtained by the application of a textured nanocrystalline Au-film-based Hilbert phase-plate. Based on the model, it is shown that monocrystalline and textured nanocrystalline phase-plate microstructures of appropriate thickness and crystalline orientation can be a promising approach for phase-contrast transmission electron microscopy. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. Transmission Electron Microscopy Characterization of Early Pre-Transition Oxides Formed on ZIRLO{sup TM}

    Energy Technology Data Exchange (ETDEWEB)

    Bae, Hoyeon; Bahn, Chi Bum [Pusan National University, Busan (Korea, Republic of); Kim, Taeho; Kim, Ji Hyun [Ulsan National Institute of Science and Technology, Ulsan (Korea, Republic of)

    2015-12-15

    Corrosion of zirconium fuel cladding is known to limit the lifetime and reloading cycles of fuel in nuclear reactors. Oxide layers formed on ZIRLOTM cladding samples, after immersion for 300-hour and 50-day in a simulated primary water chemistry condition (360 .deg. C and 20 MPa), were analyzed by using the scanning transmission electron microscopy (STEM), in-situ transmission electron microscopy (in-situ TEM) with the focused ion beam (FIB) technique, and X-ray diffraction (XRD). Both samples (immersion for 300 hours and 50 days) revealed the presence of the ZrO sub-oxide phase at the metal/oxide interface and columnar grains developed perpendicularly to the metal/oxide interface. Voids and micro-cracks were also detected near the water/oxide interface, while relatively large lateral cracks were found just above the less advanced metal/oxide interface. Equiaxed grains were mainly observed near the water/oxide interface.

  15. Revealing 3D Ultrastructure and Morphology of Stem Cell Spheroids by Electron Microscopy.

    Science.gov (United States)

    Jaros, Josef; Petrov, Michal; Tesarova, Marketa; Hampl, Ales

    2017-01-01

    Cell culture methods have been developed in efforts to produce biologically relevant systems for developmental and disease modeling, and appropriate analytical tools are essential. Knowledge of ultrastructural characteristics represents the basis to reveal in situ the cellular morphology, cell-cell interactions, organelle distribution, niches in which cells reside, and many more. The traditional method for 3D visualization of ultrastructural components, serial sectioning using transmission electron microscopy (TEM), is very labor-intensive due to contentious TEM slice preparation and subsequent image processing of the whole collection. In this chapter, we present serial block-face scanning electron microscopy, together with complex methodology for spheroid formation, contrasting of cellular compartments, image processing, and 3D visualization. The described technique is effective for detailed morphological analysis of stem cell spheroids, organoids, as well as organotypic cell cultures.

  16. Micromagnetism in (001) magnetite by spin-polarized low-energy electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Figuera, Juan de la, E-mail: juan.delafiguera@iqfr.csic.es [Instituto de Química-Física “Rocasolano”, CSIC, Madrid 28006 (Spain); Vergara, Lucía [Instituto de Química-Física “Rocasolano”, CSIC, Madrid 28006 (Spain); N' Diaye, Alpha T. [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Quesada, Adrian [Instituto de Cerámica y Vidrio, CSIC, Calle Kelsen 5, 28049, Madrid (Spain); Schmid, Andreas K. [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States)

    2013-07-15

    Spin-polarized low-energy electron microscopy was used to image a magnetite crystal with (001) surface orientation. Sets of spin-dependent images of magnetic domain patterns observed in this surface were used to map the direction of the magnetization vector with high spatial and angular resolution. We find that domains are magnetized along the surface <110> directions, and domain wall structures include 90° and 180° walls. A type of unusually curved domain walls are interpreted as Néel-capped surface terminations of 180° Bloch walls. - Highlights: ► The (001) surface of magnetite is imaged by spin-polarized low-energy electron microscopy. ► The magnetic domain microstructure is resolved. ► Magnetic easy axes in this surface are found to be along <110> directions. ► Magnetic domain wall structures include wide Néel-caps.

  17. Scanning electron microscopy analysis of experimental bone hacking trauma of the mandible.

    Science.gov (United States)

    Alunni-Perret, Véronique; Borg, Cybèle; Laugier, Jean-Pierre; Bertrand, Marie-France; Staccini, Pascal; Bolla, Marc; Quatrehomme, Gérald; Muller-Bolla, Michèle

    2010-12-01

    The authors report on a macroscopic and microscopic study of human mandible bone lesions achieved by a single-blade knife and a hatchet. The aim of this work was to complete the previous data (scanning electron microscopy analysis of bone lesions made by a single-blade knife and a hatchet, on human femurs) and to compare the lesions of the femur with those of the mandible. The results indicate that the mandible is a more fragile bone, but the features observed on the mandible are quite similar to those previously observed on the femur. This work spells out the main scanning electron microscopy characteristics of sharp (bone cutting) and blunt (exerting a pressure on the bone) mechanisms on human bone. Weapon characteristics serve to explain all of these features.

  18. Application of a grating coupler for surface plasmon polariton excitation in a photoemission electron microscopy experiment

    DEFF Research Database (Denmark)

    Leißner, Till; Jauernik, Stephan; Lemke, Christoph

    Surface plasmon polariton (SPP) excitation at a gold-vacuum interface via 800 nm light pulses mediated by a periodic array of gold ridges is probed at high lateral resolution by means of photoemission electron microscopy (PEEM). We directly monitor and quantify the coupling properties as a function...... to the grazing incidence excitation geometry intrinsic to a conventional PEEM scheme and the limited propagation distance of the SPP modes at the gold-vacuum interface at the used wavelength....

  19. Nanoparticle suspensions enclosed in methylcellulose: a new approach for quantifying nanoparticles in transmission electron microscopy

    OpenAIRE

    Christian Hacker; Jalal Asadi; Christos Pliotas; Sophie Ferguson; Lee Sherry; Phedra Marius; Javier Tello; David Jackson; James Naismith; John Milton Lucocq

    2016-01-01

    Nanoparticles are of increasing importance in biomedicine but quantification is problematic because current methods depend on indirect measurements at low resolution. Here we describe a new high-resolution method for measuring and quantifying nanoparticles in suspension. It involves premixing nanoparticles in a hydrophilic support medium (methylcellulose) before introducing heavy metal stains for visualization in small air-dried droplets by transmission electron microscopy (TEM). The use of m...

  20. Transmission Electron Microscopy of Semiconductor Nanostructures: Analysis of Composition and Strain State

    Science.gov (United States)

    Rosenauer, Andreas

    The present book is organized in the following way. The first part provides the theoretical fundamentals of transmission electron microscopy needed in the second part, which focuses on a description of strain state analysis and on the composition evaluation by lattice fringe analysis techniques. In the third part, we describe the application of these techniques to the investigation of low-dimensional semiconductor heterostructures such as InxGa1-xAs SK layers.