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Sample records for analytical electron microscopy

  1. Analytics on Transmission Electron Microscopy

    International Nuclear Information System (INIS)

    Keum, Dong Hwa; Kim, Geung Ho; Lee, Hwak Ju and others

    1996-06-01

    This book gives descriptions of transmission electron microscopy, which deals with electron microscopy and materials science, history of electron microscopy, application of analytics on transmission electron microscopy, machine requirement of transmission electron microscopy like electron gun and TEM image and function, crystal diffraction, electron diffraction, Kikuchi's diffraction figure, analysis of diffraction figure, contrast of TEM image like absorption contrast, and phase contrast, Fresnel's diffraction and TEM contrast, thickness fringe, column approximation, analysis of diffraction contrast, image simulation, and electron energy loss spectrometry.

  2. 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.

  3. Investigation of ceramic devices by analytical electron microscopy techniques

    International Nuclear Information System (INIS)

    Shiojiri, M.; Saijo, H.; Isshiki, T.; Kawasaki, M.; Yoshioka, T.; Sato, S.; Nomura, T.

    1999-01-01

    Ceramics are widely used as capacitors and varistors. Their electrical properties depend on the structure, which is deeply influenced not only by the composition of raw materials and additives but also by heating treatments in the production process. This paper reviews our investigations of SrTiO 3 ceramic devices, which have been performed using various microscopy techniques such as high-resolution transmission electron microscopy (HRTEM), cathodoluminescence scanning electron microscopy (CLSEM), field emission SEM (FE-SEM), energy dispersive X-ray spectroscopy (EDS), electron energy-loss spectroscopy (EELS) and high angle annular dark field (HAADF) imaging method in a FE-(scanning) transmission electron microscope(FE-(S)TEM). (author)

  4. 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...

  5. 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.

  6. Microstructural studies of dental amalgams using analytical transmission electron microscopy

    Science.gov (United States)

    Hooghan, Tejpal Kaur

    Dental amalgams have been used for centuries as major restorative materials for decaying teeth. Amalgams are prepared by mixing alloy particles which contain Ag, Sn, and Cu as the major constituent elements with liquid Hg. The study of microstructure is essential in understanding the setting reactions and improving the properties of amalgams. Until the work reported in this dissertation, optical microscopy (OM), scanning electron microscopy (SEM), and x-ray diffractometry (XRD) were used commonly to analyze amalgam microstructures. No previous systematic transmission electron microscopy (TEM) study has been performed due to sample preparation difficulties and composite structure of dental amalgams. The goal of this research was to carry out detailed microstructural and compositional studies of dental amalgams. This was accomplished using the enhanced spatial resolution of the TEM and its associated microanalytical techniques, namely, scanning transmission electron microscopy (STEM), x-ray energy dispersive spectroscopy (XEDS) and micro-microdiffraction (mumuD). A new method was developed for thinning amalgam samples to electron transparency using the "wedge technique." Velvalloy, a low-Cu amalgam, and Tytin, a high-Cu amalgam, were the two amalgams characterized. Velvalloy is composed of a Agsb2Hgsb3\\ (gammasb1)/HgSnsb{7-9}\\ (gammasb2) matrix surrounding unreacted Agsb3Sn (gamma) particles. In addition, hitherto uncharacterized reaction layers between Agsb3Sn(gamma)/Agsb2Hgsb3\\ (gammasb2)\\ and\\ Agsb2Hgsb3\\ (gammasb1)/HgSnsb{7-9}\\ (gammasb2) were observed and analyzed. An Ag-Hg-Sn (betasb1) phase was clearly identified for the first time. In Tytin, the matrix consists of Agsb2Hgsb3\\ (gammasb1) grains. Fine precipitates of Cusb6Snsb5\\ (etasp') are embedded inside the gammasb1 and at the grain boundaries. These precipitates are responsible for the improved creep resistance of Tytin compared to Velvalloy. The additional Cu has completely eliminated the gammasb

  7. Analytical electron microscopy of a hydrated interplanetary dust particle

    International Nuclear Information System (INIS)

    Blake, D.F.; Bunch, T.E.; Mardinly, A.J.; Echer, C.J.

    1988-01-01

    A hydrated interplanetary dust particle (IDP), IDP number-sign Ames-Dec86-11, was selected for study from a number of IDPs collected by U-2 aircraft from Ames Research Center. The particle consists primarily of a relatively nonporous aggregate of fine-grained layer silicates, some of which are in situ hydrous alteration products of pre-existing grains. The particle shows no apparent alteration due to its deceleration upon atmospheric entry. The layer silicates have a bimodal size distribution, in which matrix phyllosilicates have an apparent grain size of 10-50 nm, and phyllosilicates that pseudomorphically replace pre-existing grains have a grain size of 1-10 nm. Despite this order of magnitude difference in crystallite size, both phases are smectites, according to quantitative analytical and electron diffraction data. Euhedral to subhedral pyrrhotites, which have grain size of 0.1-1.0 μm, have high nickel contents. Pre-existing grains that have been pseudomorphed by clays are commonly surrounded or decorated with fine-grained (10-20 nm) low-nickel pentlandite. Very fine grained (1-10 nm) magnetite occurs in clusters throughout the matrix. Several fragments of a Mg-Fe silicate phase, apparently a glass, are present

  8. 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)

  9. 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.

  10. Quantifying the cellular uptake of semiconductor quantum dot nanoparticles by analytical electron microscopy.

    Science.gov (United States)

    Hondow, Nicole; Brown, M Rowan; Starborg, Tobias; Monteith, Alexander G; Brydson, Rik; Summers, Huw D; Rees, Paul; Brown, Andy

    2016-02-01

    Semiconductor quantum dot nanoparticles are in demand as optical biomarkers yet the cellular uptake process is not fully understood; quantification of numbers and the fate of internalized particles are still to be achieved. We have focussed on the characterization of cellular uptake of quantum dots using a combination of analytical electron microscopies because of the spatial resolution available to examine uptake at the nanoparticle level, using both imaging to locate particles and spectroscopy to confirm identity. In this study, commercially available quantum dots, CdSe/ZnS core/shell particles coated in peptides to target cellular uptake by endocytosis, have been investigated in terms of the agglomeration state in typical cell culture media, the traverse of particle agglomerates across U-2 OS cell membranes during endocytosis, the merging of endosomal vesicles during incubation of cells and in the correlation of imaging flow cytometry and transmission electron microscopy to measure the final nanoparticle dose internalized by the U-2 OS cells. We show that a combination of analytical transmission electron microscopy and serial block face scanning electron microscopy can provide a comprehensive description of the internalization of an initial exposure dose of nanoparticles by an endocytically active cell population and how the internalized, membrane bound nanoparticle load is processed by the cells. We present a stochastic model of an endosome merging process and show that this provides a data-driven modelling framework for the prediction of cellular uptake of engineered nanoparticles in general. © 2015 The Authors Journal of Microscopy © 2015 Royal Microscopical Society.

  11. Physical foundations of electron microscopy

    International Nuclear Information System (INIS)

    Alexander, H.

    1997-01-01

    The following topics were dealt with: Physical foundations, dynamic theory of diffraction contrasts, dynamic theory of electron diffraction, electron diffraction on crystals with defects, high-resolution electron microscopy, analytical electron microscopy

  12. Evaluating the NOx Storage Catalysts (NSC Aging: A Preliminary Analytical Study with Electronic Microscopy

    Directory of Open Access Journals (Sweden)

    Leonarda Bellebuono

    2017-10-01

    Full Text Available This paper describes an expeditious and reliable method for determining the thermal effects in a static condition of commercial NOx storage catalysts (NSCs using scanning electron microscopy with an energy dispersive X-ray analytical system (SEM/EDS. It is worth remarking that possible changes in the morphology and in the elemental composition of the catalyst may be considered as the most important causes of the lower conversion of NOx. The information attained in this work indicates that Pt nanoparticle sintering is strongly increased by the oxygen exposure, and this can be considered a very useful preliminary investigation for the studies already present in the literature on the efficiency of NSCs.

  13. Nanostructural and Chemical Characterization of Complex Oxide Catalysts by Analytical Electron Microscopy

    Science.gov (United States)

    Weng, Weihao

    Complex oxide catalysts are used as heterogeneous catalysts for producing various important organic chemicals. In this thesis, three types of complex oxide catalysts prepared using novel preparation methods have been studied. Each of them has been evaluated for its catalytic performance, namely (i) the selective oxidation of n-butane to maleic anhydride over vanadium phosphate (V-P-O) materials; (ii) the oxidative dehydrogenation (ODH) of ethane to ethylene over niobium phosphate (Nb-P-O) materials, and (iii) the oxidation of methanol to formaldehyde over iron molybdate (Fe-Mo-O) materials. Analytical electron microscopy, X-ray diffraction and other related characterization techniques have been used to provide useful information regarding the morphology, crystallography and chemical composition of these complex oxide catalysts. The underlying aim of this work is to uncover meaningful synthesis-structure-performance relationships for these three complex catalyst systems. Firstly, a standard methodology for generating V-P-O materials, i.e. the VPD route, has been revisited and modified. A variety of alkanes have been added during the alcohol reduction step of VOPO4·2H2O (dihydrate), which were found to have a remarkable influence on the morphology and structure of the V-P-O materials produced. Either VOHPO4·0.5H2O (hemihydrate) or VO(H2PO4)2 material can be produced depending on the precise alcohol:alkane volume ratio used in the reaction. In addition, the specific order in which the alkane and alcohol are added to VOPO 4·2H2O during the VPD route has a dramatic effect on the morphology of the resultant precursor. Through detailed electron microscopy studies we have been able to unveil the epitaxial relationship between the dihyrate and hemihydrate crystalline phases as being [001]dihydrate // [001]hemihydrate and [100]dihydrate // [110]hemihydrate. A two-step mechanism by which the topotactic transformation from dihydrate to hemihydrate occurs has been proposed

  14. Analytical electron microscopy of combustion particles: a comparison of vehicle exhaust and residential wood smoke

    International Nuclear Information System (INIS)

    Kocbach, A.; Johansen, B.V.; Schwarze, P.E.; Namork, E.

    2005-01-01

    Particulate matter has been associated with a number of adverse health effects. Since combustion particles from vehicle exhaust and wood smoke are common constituents of ambient air, the morphology and elemental composition of particles from these two sources were analysed and compared using single particle analysis. Ambient air particles were collected in locations dominated by vehicle exhaust or residential wood smoke. To verify the source contributions to the ambient air samples, particles were collected directly from the combustion sources. All particulate samples were analysed on carbon extraction replica by transmission electron microscopy (TEM) and X-ray microanalysis (XRMA). The particles were classified into four groups based on morphology and elemental composition. Carbon aggregates were the only particles identified to originate from combustion sources and accounted for more than 88% of the particle numbers in the ambient air samples from both sources. The carbon aggregates were therefore further analysed with respect to morphology and elemental composition on germanium extraction replica. Carbon aggregates from vehicle exhaust were characterised by higher levels of Si and Ca compared to wood smoke aggregates that contained higher levels of K. The S content in aggregates from both sources was probably caused by interaction with gases in the air. Furthermore, the diameters of primary particles from vehicle exhaust were significantly smaller (27±7 nm) than the diameters for wood smoke (38±11 nm). The observed differences in elemental profiles and primary particle diameters for vehicle exhaust and wood smoke may influence the health effects caused by these particles

  15. Comparative study of dental enamel loss after debonding braces by analytical scanning electron microscopy (SEM).

    Science.gov (United States)

    Rodríguez-Chávez, Jacqueline Adelina; Arenas-Alatorre, Jesús; Belio-Reyes, Irma Araceli

    2017-07-01

    Clinical procedures when shear forces are applied to brackets suggest adhesion forces between 2.8 and 10.0 MPa as appropriate. In this study dental enamel was evaluated by scanning electron microscopy (SEM) before and after removing the brackets. Thirty bicuspids (previous prophylaxis) with metallic brackets (Roth Inovation 0.022 GAC), Transbond Plus SEP 3M Unitek adhesive and Transbond XT 3M resin were used. The samples were preserved to 37°C during 24 hr and submited to tangential forces with the Instron Universal machine 1.0 mm/min speed load strength resistance debonding. Also the Adhesive Remanent Index (ARI) test was made, evaluating the bracket base and the bicuspid surface. All the bracket SEM images were processed with AutoCAD to determine the enamel detached area. The average value was 6.86 MPa (SD ± 3.2 MPa). ARI value 1= 63.3%, value 2= 20%, value 3= 13.3% and 33% presented value 0. All those samples with dental enamel loss, presented different situations as fractures, ledges, horizontal, and vertical loss in some cases, and some scratch lines. There is no association between the debonding resistance and enamel presence. Less than half of the remanent adhesive on the dental enamel was present in most of the samples when the ARI test was applied. When the resin area increases, the debonding resistance also increases, and when the enamel loss increases, the resin free metallic area of the bracket base decreases in the debonding. © 2017 Wiley Periodicals, Inc.

  16. Electron microscopy for Engineers

    International Nuclear Information System (INIS)

    Jones, I P

    2009-01-01

    This paper reviews the application of (mainly) Transmission Electron Microscopy (TEM) in an engineering context. The first two sections are TEM and chemical in nature; the final three sections are more general and include aspects of Scanning Electron Microscopy (SEM).

  17. 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...

  18. Electron microscopy of surfaces

    International Nuclear Information System (INIS)

    Venables, J.A.

    1981-01-01

    Electron beam techniques used to study clean surfaces and surface processes on a microscopic scale are reviewed. Recent experimental examples and possible future developments are discussed. Special emphasis is given to (i) transmission diffraction and microscopy techniques, including atomic imaging; (ii) Auger microscopy on bulk and thin film samples; (iii) secondary electron microscopy, especially low energy secondaries for work-function imaging and photoelectron imaging; and (iv) reflection electron microscopy and diffraction. (orig.)

  19. Sample Preparation Methodologies for In Situ Liquid and Gaseous Cell Analytical Transmission Electron Microscopy of Electropolished Specimens.

    Science.gov (United States)

    Zhong, Xiang Li; Schilling, Sibylle; Zaluzec, Nestor J; Burke, M Grace

    2016-12-01

    In recent years, an increasing number of studies utilizing in situ liquid and/or gaseous cell scanning/transmission electron microscopy (S/TEM) have been reported. Because of the difficulty in the preparation of suitable specimens, these environmental S/TEM studies have been generally limited to studies of nanoscale structured materials such as nanoparticles, nanowires, or sputtered thin films. In this paper, we present two methodologies which have been developed to facilitate the preparation of electron-transparent samples from conventional bulk metals and alloys for in situ liquid/gaseous cell S/TEM experiments. These methods take advantage of combining sequential electrochemical jet polishing followed by focused ion beam extraction techniques to create large electron-transparent areas for site-specific observation. As an example, we illustrate the application of this methodology for the preparation of in situ specimens from a cold-rolled Type 304 austenitic stainless steel sample, which was subsequently examined in both 1 atm of air as well as fully immersed in a H2O environment in the S/TEM followed by hyperspectral imaging. These preparation techniques can be successfully applied as a general procedure for a wide range of metals and alloys, and are suitable for a variety of in situ analytical S/TEM studies in both aqueous and gaseous environments.

  20. Vibrational spectroscopy and analytical electron microscopy studies of Fe-V-O and In-V-O thin films

    CERN Document Server

    Vuk, A S; Drazic, G; Colomban, P

    2002-01-01

    Orthovanadate (M sup 3 sup + VO sub 4; M= Fe, In) and vanadate (Fe sub 2 V sub 4 O sub 1 sub 3) thin films were prepared using sol-gel synthesis and dip coating deposition. Using analytical electron microscopy (AEM), the chemical composition and the degree of crystallization of the phases present in the thin Fe-V-O films were investigated. TEM samples were prepared in both orientations: parallel (plan view) and perpendicular (cross section) to the substrate. In the first stages of crystallization, when the particle sizes were in the nanometer range, the classical identification of phases using electron diffraction was not possible. Instead of measuring d values, experimentally selected area electron diffraction (SAED) patterns were compared to calculated (simulated) patterns in order to determine the phase composition. The problems of evaluating the ratio of amorphous and crystalline phases in thin films are reported. Results of TEM and XRD as well as IR and Raman spectroscopy showed that the films made at lo...

  1. Electron Microscopy and Analytical X-ray Characterization of Compositional and Nanoscale Structural Changes in Fossil Bone

    Science.gov (United States)

    Boatman, Elizabeth Marie

    The nanoscale structure of compact bone contains several features that are direct indicators of bulk tissue mechanical properties. Fossil bone tissues represent unique opportunities to understand the compact bone structure/property relationships from a deep time perspective, offering a possible array of new insights into bone diseases, biomimicry of composite materials, and basic knowledge of bioapatite composition and nanoscale bone structure. To date, most work with fossil bone has employed microscale techniques and has counter-indicated the survival of bioapatite and other nanoscale structural features. The obvious disconnect between the use of microscale techniques and the discernment of nanoscale structure has prompted this work. The goal of this study was to characterize the nanoscale constituents of fossil compact bone by applying a suite of diffraction, microscopy, and spectrometry techniques, representing the highest levels of spatial and energy resolution available today, and capable of complementary structural and compositional characterization from the micro- to the nanoscale. Fossil dinosaur and crocodile long bone specimens, as well as modern ratite and crocodile femurs, were acquired from the UC Museum of Paleontology. Preserved physiological features of significance were documented with scanning electron microscopy back-scattered imaging. Electron microprobe wavelength-dispersive X-ray spectroscopy (WDS) revealed fossil bone compositions enriched in fluorine with a complementary loss of oxygen. X-ray diffraction analyses demonstrated that all specimens were composed of apatite. Transmission electron microscopy (TEM) imaging revealed preserved nanocrystallinity in the fossil bones and electron diffraction studies further identified these nanocrystallites as apatite. Tomographic analyses of nanoscale elements imaged by TEM and small angle X-ray scattering were performed, with the results of each analysis further indicating that nanoscale structure is

  2. Microscopy with slow electrons

    International Nuclear Information System (INIS)

    Frank, L.; Muellerova, I.; Delong, A.

    1994-01-01

    Low energy microscopy is treated as the low energy limit of electron microscopy as a whole in all its basic branches, i.e., the emission, transmission and scanning microscopy. The instrumental and methodological aspects are briefly discussed. They include the interaction of electrons with a solid, the contrast formation mechanisms, the instrumentation problems, and actual progress achieved in all three types of microscopy from the point of view of lowering the energy of electrons, impacting or leaving the specimen, down to the low energy range below 5 keV and the very low energy range below 50 eV. (author) 62 refs., 27 figs., 3 tabs

  3. Assessment of occupational exposure to asbestos fibers: Contribution of analytical transmission electron microscopy analysis and comparison with phase-contrast microscopy.

    Science.gov (United States)

    Eypert-Blaison, Céline; Romero-Hariot, Anita; Clerc, Frédéric; Vincent, Raymond

    2018-03-01

    From November 2009 to October 2010, the French general directorate for labor organized a large field-study using analytical transmission electron microscopy (ATEM) to characterize occupational exposure to asbestos fibers during work on asbestos containing materials (ACM). The primary objective of this study was to establish a method and to validate the feasibility of using ATEM for the analysis of airborne asbestos of individual filters sampled in various occupational environments. For each sampling event, ATEM data were compared to those obtained by phase-contrast optical microscopy (PCOM), the WHO-recommended reference technique. A total of 265 results were obtained from 29 construction sites where workers were in contact with ACM. Data were sorted depending on the combination of the ACM type and the removal technique. For each "ACM-removal technique" combination, ATEM data were used to compute statistical indicators on short, fine and WHO asbestos fibers. Moreover, exposure was assessed taking into account the use of respiratory protective devices (RPD). As in previous studies, no simple relationship was found between results by PCOM and ATEM counting methods. Some ACM, such as asbestos-containing plasters, generated very high dust levels, and some techniques generated considerable levels of dust whatever the ACM treated. On the basis of these observations, recommendations were made to measure and control the occupational exposure limit. General prevention measures to be taken during work with ACM are also suggested. Finally, it is necessary to continue acquiring knowledge, in particular regarding RPD and the dust levels measured by ATEM for the activities not evaluated during this study.

  4. 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.

  5. Identifying the crystallinity, phase, and arsenic uptake of the nanomineral schwertmannite using analytical high resolution transmission electron microscopy

    Science.gov (United States)

    French, R. A.; Kim, B.; Murayama, M.; Hochella, M. F.

    2010-12-01

    Schwertmannite, an iron oxyhydroxide sulfate nanomineral, plays a significant role in the geochemistry of acid mine drainage (AMD) as a metastable phase with respect to goethite and by retaining toxic metals, e.g. arsenic [1]. Schwertmannite’s characteristic morphology is needles 100-300 nm long and only 5-10 nm in diameter extending from a dense aggregate. The poorly-and nano-crystalline nature of this mineral requires using high resolution electron microscopy (HRTEM) to be fully characterized. We used HRTEM to identify the polyphasic nature of natural samples of schwertmannite collected from the Iberian Pyrite Belt in Spain. In order to analyze the dense core, samples were prepared in thin section using an ultramicrotome. Data on a sample identified as pure schwertmannite through powder XRD shows the presence of 5-10 nm goethite nanocrystals making up a significant portion of one of the nanoneedle tips (Figure 1). These nanocrystals exhibit lattice fringes and faceted surfaces, both of which match that expected for goethite. The great majority of the nanoneedles are poorly-crystalline (no lattice fringes) with atomically rough surfaces which may be highly active in the uptake of As. The presence of a range of phases and crystallinities in this sample demonstrate incipient stages of the mechanism that results in transformation of schwertmannite to goethite. Further analytical TEM analyses will help us track sorption/desorption, as well as the specific locations of As within these materials upon initial formation, as well as during transformation. [1] Acero et al. (2006) GCA 70, 4130-4139. Figure 1. HRTEM image of 'schwertmannite' nanoneedle with FFT data (inset).

  6. An in-situ analytical scanning and transmission electron microscopy investigation of structure-property relationships in electronic materials

    Science.gov (United States)

    Wagner, Andrew James

    As electronic and mechanical devices are scaled downward in size and upward in complexity, macroscopic principles no longer apply. Synthesis of three-dimensionally confined structures exhibit quantum confinement effects allowing, for example, silicon nanoparticles to luminesce. The reduction in size of classically brittle materials reveals a ductile-to-brittle transition. Such a transition, attributed to a reduction in defects, increases elasticity. In the case of silicon, elastic deformation can improve electronic carrier mobility by over 50%, a vital attribute of modern integrated circuits. The scalability of such principles and the changing atomistic processes which contribute to them presents a vitally important field of research. Beginning with the direct observation of dislocations and lattice planes in the 1950s, the transmission electron microscope has been a powerful tool in materials science. More recently, as nanoscale technologies have proliferated modern life, their unique ability to spatially resolve nano- and atomic-scale structures has become a critical component of materials research and characterization. Signals produced by an incident beam of high-energy electrons enables researchers to both image and chemically analyze materials at the atomic scale. Coherently and elastically-scattered electrons can be collected to produce atomic-scale images of a crystalline sample. New specimen stages have enabled routine investigation of samples heated up to 1000 °C and cooled to liquid nitrogen temperatures. MEMS-based transducers allow for sub-nm scale mechanical testing and ultrathin membranes allow study of liquids and gases. Investigation of a myriad of previously "unseeable" processes can now be observed within the TEM, and sometimes something new is found within the old. High-temperature annealing of pure a Si:H films leads to crystallization of the film. Such films provide higher carrier mobility compared to amorphous films, offering improved

  7. Electron microscopy and diffraction

    International Nuclear Information System (INIS)

    Gjoennes, J.; Olsen, A.

    1986-01-01

    This report is a description of research activities and plans at the electron microscopy laboratorium, Physics Department, University of Oslo. Since the first electron microscope was installed in 1968, the research has covered inorganic structures, physical metallurgy, as well as theory of electron scattering and the development of methods in this field. The current plans involve efforts in the development of crystallographic and spectroscopic methods

  8. 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.

  9. Analytical Electron Microscope

    Data.gov (United States)

    Federal Laboratory Consortium — The Titan 80-300 is a transmission electron microscope (TEM) equipped with spectroscopic detectors to allow chemical, elemental, and other analytical measurements to...

  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. Linear least-squares fit evaluation of series of analytical spectra from planar defects: extension and possible implementations in scanning transmission electron microscopy.

    Science.gov (United States)

    Walther, T

    2006-08-01

    In a previous paper, a new technique was introduced to determine the chemistry of crystallographically well-defined planar defects (such as straight interfaces, grain boundaries, twins, inversion or antiphase domain boundaries) in the presence of homogeneous solute segregation or selective doping. The technique is based on a linear least-squares fit using series of analytical (electron energy-loss or energy-dispersive X-ray) spectra acquired in a transmission electron microscope that is operated in nano-probe mode with the planar defect centred edge-on. First, additional notes on the use of proper k-factors and determination of Gibbsian excess segregation are given in this note. Using simulated data sets, it is shown that the linear least-squares fit improves both the accuracy and the robustness to noise beyond that obtainable by independently repeated measurements. It is then shown how the method originally developed for a stationary nano-probe mode in transmission electron microscopy can be extended to a focused electron beam that scans a square region in scanning transmission electron microscopy. The necessary modifications to scan geometry and corresponding numerical evaluation are described, and three different practical implementations are proposed.

  12. Localization and chemical forms of cadmium in plant samples by combining analytical electron microscopy and X-ray spectromicroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Isaure, Marie-Pierre [Section d' Application des Traceurs, LITEN, CEA-Grenoble, 17, rue des Martyrs, 38054 Grenoble cedex 9 (France) and Environmental Geochemistry Group, LGIT, UMR 5559, Universite J. Fourier and CNRS, BP 53, 38041 Grenoble cedex 9 (France)]. E-mail: mpisaure@ujf-grenoble.fr; Fayard, Barbara [Laboratoire de Physique des Solides, UMR 8502 Universite Paris Sud, 91405 Orsay (France); European Synchrotron Radiation Facility, ID-21, BP220, 38043 Grenoble (France); Sarret, Geraldine [Environmental Geochemistry Group, LGIT, UMR 5559, Universite J. Fourier and CNRS, BP 53, 38041 Grenoble cedex 9 (France); Pairis, Sebastien [Laboratoire de Cristallographie, UPR 5031, 25 Avenue des Martyrs, BP 166, 38042 Grenoble cedex 9 (France); Bourguignon, Jacques [Laboratoire de Physiologie Cellulaire Vegetale, UMR 5168 CEA/CNRS/INRA/UJF, DRDC, CEA-Grenoble, 17 Avenue des Martyrs, 38054 Grenoble cedex 9 (France)

    2006-12-15

    Cadmium (Cd) is a metal of high toxicity for plants. Resolving its distribution and speciation in plants is essential for understanding the mechanisms involved in Cd tolerance, trafficking and accumulation. The model plant Arabidopsis thaliana was exposed to cadmium under controlled conditions. Elemental distributions in the roots and in the leaves were determined using scanning electron microscopy coupled with energy dispersive X-ray microanalysis (SEM-EDX), and synchrotron-based micro X-ray fluorescence ({mu}-XRF), which offers a better sensitivity. The chemical form(s) of cadmium was investigated using Cd L{sub III}-edge (3538 eV) micro X-ray absorption near edge structure ({mu}-XANES) spectroscopy. Plant {mu}-XANES spectra were fitted by linear combination of Cd reference spectra. Biological sample preparation and conditioning is a critical point because of possible artifacts. In this work we compared freeze-dried samples analyzed at ambient temperature and frozen hydrated samples analyzed at -170 deg. C. Our results suggest that in the roots Cd is localized in vascular bundles, and coordinated to S ligands. In the leaves, trichomes (epidermal hairs) represent the main compartment of Cd accumulation. In these specialized cells, {mu}-XANES results show that the majority of Cd is bound to O/N ligands likely provided by the cell wall, and a minor fraction could be bound to S-containing ligands. No significant difference in Cd speciation was observed between freeze-dried and frozen hydrated samples. This work illustrates the interest and the sensitivity of Cd L{sub III}-edge XANES spectroscopy, which is applied here for the first time to plant samples. Combining {mu}-XRF and Cd L{sub III}-edge {mu}-XANES spectroscopy offers promising tools to study Cd storage and trafficking mechanisms in plants and other biological samples.

  13. 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

  14. Advanced Electron Microscopy and Micro analytical technique development and application for Irradiated TRISO Coated Particles from the AGR-1 Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Van Rooyen, Isabella Johanna [Idaho National Lab. (INL), Idaho Falls, ID (United States); Lillo, Thomas Martin [Idaho National Lab. (INL), Idaho Falls, ID (United States); Wen, Haiming [Idaho National Lab. (INL), Idaho Falls, ID (United States); Wright, Karen Elizabeth [Idaho National Lab. (INL), Idaho Falls, ID (United States); Madden, James Wayne [Idaho National Lab. (INL), Idaho Falls, ID (United States); Aguiar, Jeffery Andrew [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2017-01-01

    A series of up to seven irradiation experiments are planned for the Advanced Gas Reactor (AGR) Fuel Development and Quantification Program, with irradiation completed at the Advanced Test Reactor (ATR) at Idaho National Laboratory (INL) for the first experiment (i.e., AGR-1) in November 2009 for an effective 620 full power days. The objective of the AGR-1 experiment was primarily to provide lessons learned on the multi-capsule test train design and to provide early data on fuel performance for use in fuel fabrication process development and post-irradiation safety testing data at high temperatures. This report describes the advanced microscopy and micro-analysis results on selected AGR-1 coated particles.

  15. Scanning electron microscopy physics of image formation and microanalysis

    CERN Document Server

    Reimer, Ludwig

    1998-01-01

    Scanning Electron Microscopy provides a description of the physics of electron-probe formation and of electron-specimen interations The different imaging and analytical modes using secondary and backscattered electrons, electron-beam-induced currents, X-ray and Auger electrons, electron channelling effects, and cathodoluminescence are discussed to evaluate specific contrasts and to obtain quantitative information

  16. 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…

  17. Four-dimensional electron microscopy.

    Science.gov (United States)

    Zewail, Ahmed H

    2010-04-09

    The discovery of the electron over a century ago and the realization of its dual character have given birth to one of the two most powerful imaging instruments: the electron microscope. The electron microscope's ability to resolve three-dimensional (3D) structures on the atomic scale is continuing to affect different fields, including materials science and biology. In this Review, we highlight recent developments and inventions made by introducing the fourth dimension of time in electron microscopy. Today, ultrafast electron microscopy (4D UEM) enables a resolution that is 10 orders of magnitude better than that of conventional microscopes, which are limited by the video-camera rate of recording. After presenting the central concept involved, that of single-electron stroboscopic imaging, we discuss prototypical applications, which include the visualization of complex structures when unfolding on different length and time scales. The developed UEM variant techniques are several, and here we illucidate convergent-beam and near-field imaging, as well as tomography and scanning-pulse microscopy. We conclude with current explorations in imaging of nanomaterials and biostructures and an outlook on possible future directions in space-time, 4D electron microscopy.

  18. Four-Dimensional Electron Microscopy

    Science.gov (United States)

    Zewail, Ahmed H.

    2010-04-01

    The discovery of the electron over a century ago and the realization of its dual character have given birth to one of the two most powerful imaging instruments: the electron microscope. The electron microscope’s ability to resolve three-dimensional (3D) structures on the atomic scale is continuing to affect different fields, including materials science and biology. In this Review, we highlight recent developments and inventions made by introducing the fourth dimension of time in electron microscopy. Today, ultrafast electron microscopy (4D UEM) enables a resolution that is 10 orders of magnitude better than that of conventional microscopes, which are limited by the video-camera rate of recording. After presenting the central concept involved, that of single-electron stroboscopic imaging, we discuss prototypical applications, which include the visualization of complex structures when unfolding on different length and time scales. The developed UEM variant techniques are several, and here we illucidate convergent-beam and near-field imaging, as well as tomography and scanning-pulse microscopy. We conclude with current explorations in imaging of nanomaterials and biostructures and an outlook on possible future directions in space-time, 4D electron microscopy.

  19. 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...

  20. In Situ Transmission Electron Microscopy for Electronics

    OpenAIRE

    Arita, Masashi; Hamada, Kouichi; Takahashi, Yasuo; Sueoka, Kazuhisa; Shibayama, Tamaki

    2015-01-01

    Electronic devices are strongly influenced by their microstructures. In situ transmission electron microscopy (in situ TEM) with capability to measure electrical properties is an effective method to dynamically correlate electric properties with microstructures. We have developed tools and in situ TEM experimental procedures for measuring electronic devices, including TEM sample holders and sample preparation methods. The method was used to study metallic nanowire by electromigration, magn...

  1. A high-resolution analytical scanning transmission electron microscopy study of the early stages of spinodal decomposition in binary Fe–Cr

    Energy Technology Data Exchange (ETDEWEB)

    Westraadt, J.E., E-mail: johan.westraadt@nmmu.ac.za [Centre for High Resolution TEM, Nelson Mandela Metropolitan University, University Way, Port Elizabeth 6031 (South Africa); Olivier, E.J.; Neethling, J.H. [Centre for High Resolution TEM, Nelson Mandela Metropolitan University, University Way, Port Elizabeth 6031 (South Africa); Hedström, P.; Odqvist, J.; Xu, X. [Dept. Materials Science and Engineering, KTH Royal Institute of Technology, Brinellvägen 23, 10044 Stockholm (Sweden); Steuwer, A. [Nelson Mandela Metropolitan University, Gardham Av., Port Elizabeth 6031 (South Africa)

    2015-11-15

    Spinodal decomposition (SD) is an important phenomenon in materials science and engineering. For example, it is considered to be responsible for the 475 °C embrittlement of stainless steels comprising the bcc (ferrite) or bct (martensite) phases. Structural characterization of the evolving minute nano-scale concentration fluctuations during SD in the Fe–Cr system is, however, a notable challenge, and has mainly been considered accessible via atom probe tomography (APT) and small-angle neutron scattering. The standard tool for nanostructure characterization, viz. transmission electron microscopy (TEM), has only been successfully applied to late stages of SD when embrittlement is already severe. However, we here demonstrate that the structural evolution in the early stages of SD in binary Fe–Cr, and alloys based on the binary, are accessible via analytical scanning TEM. An Fe–36 wt% Cr alloy aged at 500 °C for 1, 10 and 100 h is investigated using an aberration-corrected microscope and it is found that highly coherent and interconnected Cr-rich regions develop. The wavelength of decomposition is rather insensitive to the sample thickness and it is quantified to 2, 3 and 6 nm after ageing for 1, 10 and 100 h, which is in reasonable agreement with prior APT analysis. The concentration amplitude is more sensitive to the sample thickness and acquisition parameters but the TEM analysis is in good agreement with APT analysis for the longest ageing time. These findings open up for combinatorial TEM studies where both local crystallography and chemistry is required. - Highlights: • STEM-EELS analysis was successfully applied to resolve early stage SD in Fe–Cr. • Compositional wavelength measured with STEM-EELS compares well to previous ATP studies. • Compositional amplitude measured with STEM-EELS is a function of experimental parameters. • STEM-EELS allows for combinatorial studies of SD using complementary techniques.

  2. 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...

  3. Transmission electron microscopy of bone

    NARCIS (Netherlands)

    Everts, Vincent; Niehof, Anneke; Tigchelaar-Gutter, Wikky; Beertsen, Wouter

    2012-01-01

    This chapter describes procedures to process mineralized tissues obtained from different sources for transmission electron microscopy (TEM). Methods for fixation, resin embedding, staining of semi-thin sections and ultrathin sections are presented. In addition, attention will be paid to processing

  4. 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

  5. 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

  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, composi......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....... The holder is implemented with a laser diode and an optical system that guides the light onto the sample surface with maximum power transmission. The source can be changed and tuned according to the needs, in principle spanning the whole visible and UV light spectrum. It is possible to use the device inside...

  7. CNNs for electron microscopy segmentation

    OpenAIRE

    García-Amorena García, Pablo

    2013-01-01

    In the framework of Biomedicine, mitochondria are known to play an important role in neural function. Recent studies show mitochondrial morphology to be crucial to cellular physiology and synaptic function, and a link between mitochondrial defects and neuro-degenerative diseases is strongly suspected. Electron microscopy (EM), with its very high resolution in all three directions, is one of the key tools to look more closely into these tissues, but the huge amounts of data it produces m...

  8. 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

  9. 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

  10. Electron holography for polymer microscopy

    International Nuclear Information System (INIS)

    Joy, D.C.

    1992-01-01

    Electron holography provides a radically new approach to the problem of imaging objects such as macromolecules, which exhibit little or no contrast when viewed in the conventional transmission electron microscope (TEM). This is overcome in electron holography by using the macromolecule as a phase object. Computer reconstruction of the hologram then allows the phase to be viewed as an image, and amplified. Holography requires a TEM with a field emission gun, and with an electro-static biprism to produce the interference pattern. The hologram requires a similar radiation dose to conventional microscopy but many different images (e.g. a through focal series) can be extracted from the same hologram. Further developments of the technique promise to combine high contrast imaging of the bulk of the macromolecule together with high spatial resolution imaging of surface detail

  11. Microscopy of electronic wave function

    International Nuclear Information System (INIS)

    Harb, M.

    2010-01-01

    This work of thesis aims to visualize, on a position sensitive detector, the spatial oscillations of slow electrons (∼ 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)

  12. 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

  13. Electron Microscopy Society of Southern Africa : proceedings

    International Nuclear Information System (INIS)

    Snyman, H.C.; Coetzee, J.; Coubrough, R.I.

    1987-01-01

    The proceedings of the 26th annual conference of the Electron Microscopy Society of Southern Africa are presented. Papers were presented on the following topics: techniques and instrumentation used in electron microscopy, and applications of electron microscopy in the life sciences, including applications in medicine, zoology, botany and microbiology. The use of electron microscopy in the physical sciences was also discussed. Separate abstracts were prepared for seven of the papers presented. The remaining papers were considered outside the subject scope of INIS

  14. 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

  15. 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).

  16. 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

  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. The influence of C{sub s}/C{sub c} correction in analytical imaging and spectroscopy in scanning and transmission electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Zaluzec, Nestor J., E-mail: zaluzec@microscopy.com

    2015-04-15

    Aberration correction in scanning/transmission electron microscopy (S/TEM) owes much to the efforts of a small dedicated group of innovators. Leading that frontier has been Prof. Harald Rose. To date his leadership and dynamic personality has spearheaded our ability to leave behind many of the limitations imposed by spherical aberration (C{sub s}) in high resolution phase contrast imaging. Following shortly behind, has been the development of chromatic aberration correction (C{sub c}) which augments those accomplishments. In this paper we will review and summarize how the combination of C{sub s}/C{sub c} technology enhances our ability to conduct hyperspectral imaging and spectroscopy in today's and future computationally mediated experiments in both thin as well as realistic specimens in vacuo and during in-situ/environmental experiments.

  19. Hyperspectral microscopy as an analytical tool for nanomaterials.

    Science.gov (United States)

    Roth, Gary A; Tahiliani, Sahil; Neu-Baker, Nicole M; Brenner, Sara A

    2015-01-01

    Hyperspectral microscopy is an advanced visualization technique that combines hyperspectral imaging with state-of-the-art optics and computer software to enable the rapid identification of materials at the micro- and nanoscales. Achieving this level of resolution has traditionally required time-consuming and costly electron microscopy techniques. While hyperspectral microscopy has already been applied to the analysis of bulk materials and biologicals, it shows extraordinary promise as an analytical tool to locate individual nanoparticles and aggregates in complex samples through rapid optical and spectroscopic identification. This technique can be used to not only screen for the presence of nanomaterials, but also to locate, identify, and characterize them. It could also be used to identify a subset of samples that would then move on for further analysis via other advanced metrology. This review will describe the science and origins of hyperspectral microscopy, examine current and emerging applications in life science, and examine potential applications of this technology that could improve research efficiency or lead to novel discoveries. © 2015 Wiley Periodicals, Inc.

  20. Analytical purpose electron backscattering system

    International Nuclear Information System (INIS)

    Desdin, L.; Padron, I.; Laria, J.

    1996-01-01

    In this work an analytical purposes electron backscattering system improved at the Center of Applied Studies for Nuclear Development is described. This system can be applied for fast, exact and nondestructive testing of binary and AL/Cu, AL/Ni in alloys and for other applications

  1. Study of surface reaction of spinel Li4Ti5O12 during the first lithium insertion and extraction processes using atomic force microscopy and analytical transmission electron microscopy.

    Science.gov (United States)

    Kitta, Mitsunori; Akita, Tomoki; Maeda, Yasushi; Kohyama, Masanori

    2012-08-21

    Spinel lithium titanate (Li(4)Ti(5)O(12), LTO) is a promising anode material for a lithium ion battery because of its excellent properties such as high rate charge-discharge capability and life cycle stability, which were understood from the viewpoint of bulk properties such as small lattice volume changes by lithium insertion. However, the detailed surface reaction of lithium insertion and extraction has not yet been studied despite its importance to understand the mechanism of an electrochemical reaction. In this paper, we apply both atomic force microscopy (AFM) and transmission electron microscopy (TEM) to investigate the changes in the atomic and electronic structures of the Li(4)Ti(5)O(12) surface during the charge-discharged (lithium insertion and extraction) processes. The AFM observation revealed that irreversible structural changes of an atomically flat Li(4)Ti(5)O(12) surface occurs at the early stage of the first lithium insertion process, which induces the reduction of charge transfer resistance at the electrolyte/Li(4)Ti(5)O(12) interface. The TEM observation clarified that cubic rock-salt crystal layers with a half lattice size of the original spinel structure are epitaxially formed after the first charge-discharge cycle. Electron energy loss spectroscopy (EELS) observation revealed that the formed surface layer should be α-Li(2)TiO(3). Although the transformation of Li(4)Ti(5)O(12) to Li(7)Ti(5)O(12) is well-known as the lithium insertion reaction of the bulk phase, the generation of surface product layers should be inevitable in real charge-discharge processes and may play an effective role in the stable electrode performance as a solid-electrolyte interphase (SEI).

  2. 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.

  3. Dark Field Microscopy for Analytical Laboratory Courses

    Science.gov (United States)

    Augspurger, Ashley E.; Stender, Anthony S.; Marchuk, Kyle; Greenbowe, Thomas J.; Fang, Ning

    2014-01-01

    An innovative and inexpensive optical microscopy experiment for a quantitative analysis or an instrumental analysis chemistry course is described. The students have hands-on experience with a dark field microscope and investigate the wavelength dependence of localized surface plasmon resonance in gold and silver nanoparticles. Students also…

  4. 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.

  5. Usage of scanning electron microscopy for particulate matter sources identification

    Czech Academy of Sciences Publication Activity Database

    Ličbinský, R.; Frýbort, O.; Huzlík, J.; Adamec, V.; Effenberger, K.; Mikuška, Pavel; Vojtěšek, Martin; Křůmal, Kamil

    2010-01-01

    Roč. 3, č. 3 (2010), s. 137-144 ISSN 1802-971X R&D Projects: GA MŽP SP/1A3/55/08 Institutional research plan: CEZ:AV0Z40310501 Keywords : morphology * scanning electron microscopy * sources Subject RIV: CB - Analytical Chemistry, Separation

  6. Very low energy scanning electron microscopy

    Czech Academy of Sciences Publication Activity Database

    Frank, Luděk; Hovorka, Miloš; Konvalina, Ivo; Mikmeková, Šárka; Müllerová, Ilona

    2011-01-01

    Roč. 645, č. 1 (2011), s. 46-54 ISSN 0168-9002 R&D Projects: GA MŠk OE08012 Institutional research plan: CEZ:AV0Z20650511 Keywords : scanning electron microscopy * low energy electrons * cathode lens * very low energy STEM * grain contrast Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 1.207, year: 2011

  7. 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.

  8. 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...

  9. Electron microscopy of nuclear zirconium alloys

    International Nuclear Information System (INIS)

    Versaci, R.A.; Ipohorski, Miguel

    1986-01-01

    Transmission electron microscopy observations of the microstructure of zirconium alloys used in fuel sheaths of nuclear power reactors are reported. Specimens were observed after different thermal and mechanical treatment, similar to those actually used during fabrication of the sheaths. Electron micrographs and electron diffraction patterns of second phase particles present in zircaloy-2 and zircaloy-4 were also obtained, as well as some characteristic parameters. Images of oxides and hydrides most commonly present in zirconium alloys are also shown. Finally, the structure of a Zr-2,5Nb alloy used in CANDU reactors pressure tubes, is observed by electron microscopy. (Author) [es

  10. Compressed Sensing and Electron Microscopy

    Science.gov (United States)

    2010-01-01

    solver for (2.20) which, however, works (in the spirit of a homotopy method ) on “nearby” minimization problems of the form argmin x λhµ(x) + 1 2 ‖Φx− b‖22...electron microscopes play a central role in the analysis of the composition and structure of materials [23, 32]. In particular, processing the data...from STEM (scanning transmission electron microscopes [22, 2]), is becoming increasingly im- portant for the analysis of biological and other soft

  11. 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

  12. Electron Microscopy of Intracellular Protozoa.

    Science.gov (United States)

    1980-08-01

    concentrations of antiserum were utilized, the addition of complement profoundly amplified the as socia - tion of trypanosomes and macrophages. Electron...of media for 120 mi. Please contrast with Fig. 7 (15 min incubation with immune serum) and Fig 9 (120 min with immune serum). Arrow indicates

  13. 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 se...

  14. Low voltage transmission electron microscopy of graphene.

    Science.gov (United States)

    Bachmatiuk, Alicja; Zhao, Jiong; Gorantla, Sandeep Madhukar; Martinez, Ignacio Guillermo Gonzalez; Wiedermann, Jerzy; Lee, Changgu; Eckert, Juergen; Rummeli, Mark Hermann

    2015-02-04

    The initial isolation of graphene in 2004 spawned massive interest in this two-dimensional pure sp(2) carbon structure due to its incredible electrical, optical, mechanical, and thermal effects. This in turn led to the rapid development of various characterization tools for graphene. Examples include Raman spectroscopy and scanning tunneling microscopy. However, the one tool with the greatest prowess for characterizing and studying graphene is the transmission electron microscope. State-of-the-art (scanning) transmission electron microscopes enable one to image graphene with atomic resolution, and also to conduct various other characterizations simultaneously. The advent of aberration correctors was timely in that it allowed transmission electron microscopes to operate with reduced acceleration voltages, so that damage to graphene is avoided while still providing atomic resolution. In this comprehensive review, a brief introduction is provided to the technical aspects of transmission electron microscopes relevant to graphene. The reader is then introduced to different specimen preparation techniques for graphene. The different characterization approaches in both transmission electron microscopy and scanning transmission electron microscopy are then discussed, along with the different aspects of electron diffraction and electron energy loss spectroscopy. The use of graphene for other electron microscopy approaches such as in-situ investigations is also presented. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. National Center for Electron Microscopy users' guide

    International Nuclear Information System (INIS)

    1987-01-01

    The National Center for Electron Microscopy (NCEM) in the Materials and Molecular Research Division of the Lawrence Berkeley Laboratory is a high voltage electron microscope facility for ultra-high resolution or dynamic in-situ studies. This guide describes the instruments and their specifications, support instrumentation, and user policies. Advice as to travel and accommodations is provided in the guide. (FI)

  16. Electron Microscopy of Natural and Epitaxial Diamond

    Science.gov (United States)

    Posthill, J. B.; George, T.; Malta, D. P.; Humphreys, T. P.; Rudder, R. A.; Hudson, G. C.; Thomas, R. E.; Markunas, R. J.

    1993-01-01

    Semiconducting diamond films have the potential for use as a material in which to build active electronic devices capable of operating at high temperatures or in high radiation environments. Ultimately, it is preferable to use low-defect-density single crystal diamond for device fabrication. We have previously investigated polycrystalline diamond films with transmission electron microscopy (TEM) and scanning electron microscopy (SEM), and homoepitaxial films with SEM-based techniques. This contribution describes some of our most recent observations of the microstructure of natural diamond single crystals and homoepitaxial diamond thin films using TEM.

  17. 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.

  18. Scanning Electron Microscopy Sample Preparation and Imaging.

    Science.gov (United States)

    Nguyen, Jenny Ngoc Tran; Harbison, Amanda M

    2017-01-01

    Scanning electron microscopes allow us to reach magnifications of 20-130,000× and resolve compositional and topographical images with intense detail. These images are created by bombarding a sample with electrons in a focused manner to generate a black and white image from the electrons that bounce off of the sample. The electrons are detected using positively charged detectors. Scanning electron microscopy permits three-dimensional imaging of desiccated specimens or wet cells and tissues by using variable pressure chambers. SEM ultrastructural analysis and intracellular imaging supplement light microscopy for molecular profiling of prokaryotes, plants, and mammals. This chapter demonstrates how to prepare and image samples that are (a) desiccated and conductive, (b) desiccated and nonconductive but coated with an electron conductive film using a gold sputter coater, and (c) wet and maintained in a hydrated state using a Deben Coolstage.

  19. Dinosaur eggshell study using scanning electron microscopy.

    Science.gov (United States)

    Jackson, Frankie D; Schweitzer, Mary H; Schmitt, James G

    2002-01-01

    Visualization and analysis of structural features in fossil dinosaur eggs by scanning electron microscopy augment information from traditional petrographic light microscopy. Comparison of characteristics in fossil and modern eggshells allows inferences to be made regarding dinosaur reproductive biology, physiology, and evolutionary relationships. Assessment of diagenetic alteration of primary eggshell calcite structure that occurs during fossilization provides important information necessary for taxonomic identification and paleoenvironmental interpretations.

  20. Quantitative transmission electron microscopy at atomic resolution

    International Nuclear Information System (INIS)

    Allen, L J; D'Alfonso, A J; Forbes, B D; Findlay, S D; LeBeau, J M; Stemmer, S

    2012-01-01

    In scanning transmission electron microscopy (STEM) it is possible to operate the microscope in bright-field mode under conditions which, by the quantum mechanical principle of reciprocity, are equivalent to those in conventional transmission electron microscopy (CTEM). The results of such an experiment will be presented which are in excellent quantitative agreement with theory for specimens up to 25 nm thick. This is at variance with the large contrast mismatch (typically between two and five) noted in equivalent CTEM experiments. The implications of this will be discussed.

  1. Comparative study of electron microscopy and scanning probe microscopy in photosynthetic research

    OpenAIRE

    MATĚNOVÁ, Martina

    2009-01-01

    The aim of this study is to compare the ability of transmission electron microscopy, scanning electron microscopy and atomic force microscopy to visualize individual protein complexes. The principle of electron microscopy and atomic force microscopy is explained. For comparision of these methods well characterized photosynthetic complexes LH1, LH2, PSI and PSII were selected.

  2. Proximity Scanning Transmission Electron Microscopy/Spectroscopy

    OpenAIRE

    Hwang, Ing-Shouh

    2016-01-01

    Here a new microscopic method is proposed to image and characterize very thin samples like few-layer materials, organic molecules, and nanostructures with nanometer or sub-nanometer resolution using electron beams of energies lower than 20 eV. The microscopic technique achieves high resolution through the proximity (or near-field) effect, as in scanning tunneling microscopy (STM), while it also allows detection of transmitted electrons for imaging and spectroscopy, as in scanning transmission...

  3. 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.

  4. 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.

  5. Electron Microscopy of Nanostructures in Cells

    DEFF Research Database (Denmark)

    Købler, Carsten

    with cells is therefore increasingly more relevant from both an engineering and a toxicological viewpoint. My work involves developing and exploring electron microscopy (EM) for imaging nanostructures in cells, for the purpose of understanding nanostructure-cell interactions in terms of their possibilities...

  6. Phosphogypsum surface characterisation using scanning electron microscopy

    Directory of Open Access Journals (Sweden)

    Rajković Miloš B.

    2003-01-01

    Full Text Available This paper presents the results of application of Scanning Electron Microscopy (SEM to examinations of the samples of natural gypsum and phosphogypsum. Phosphogypsum has a well developed crystalline structure, and appear in two polymorphous forms, of rombic and hexagonal shape crystals. Natural gypsum has a poorly crystalline structure. The differences in crystalline structure influence the chemical behavior of these row materials.

  7. Energetic materials research using scanning electron microscopy

    NARCIS (Netherlands)

    Elshout, J.J.M.H. van den; Duvalois, W.; Benedetto, G.L. Di; Bouma, R.H.B.; Heijden, A.E.D.M. van der

    2016-01-01

    A key-technique for the research of energetic materials is scanning electron microscopy. In this paper several examples are given of characterization studies on energetic materials, including a solid composite propellant formulation. Results of the characterization of energetic materials using

  8. Correlated Raman micro-spectroscopy and scanning electron microscopy analyses of flame retardants in environmental samples: a micro-analytical tool for probing chemical composition, origin and spatial distribution.

    Science.gov (United States)

    Ghosal, Sutapa; Wagner, Jeff

    2013-07-07

    We present correlated application of two micro-analytical techniques: scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS) and Raman micro-spectroscopy (RMS) for the non-invasive characterization and molecular identification of flame retardants (FRs) in environmental dusts and consumer products. The SEM/EDS-RMS technique offers correlated, morphological, molecular, spatial distribution and semi-quantitative elemental concentration information at the individual particle level with micrometer spatial resolution and minimal sample preparation. The presented methodology uses SEM/EDS analyses for rapid detection of particles containing FR specific elements as potential indicators of FR presence in a sample followed by correlated RMS analyses of the same particles for characterization of the FR sub-regions and surrounding matrices. The spatially resolved characterization enabled by this approach provides insights into the distributional heterogeneity as well as potential transfer and exposure mechanisms for FRs in the environment that is typically not available through traditional FR analysis. We have used this methodology to reveal a heterogeneous distribution of highly concentrated deca-BDE particles in environmental dust, sometimes in association with identifiable consumer materials. The observed coexistence of deca-BDE with consumer material in dust is strongly indicative of its release into the environment via weathering/abrasion of consumer products. Ingestion of such enriched FR particles in dust represents a potential for instantaneous exposure to high FR concentrations. Therefore, correlated SEM/RMS analysis offers a novel investigative tool for addressing an area of important environmental concern.

  9. Analyticity of the density of electronic wavefunctions

    DEFF Research Database (Denmark)

    Sørensen, Thomas Østergaard; Fournais, S.; Hoffmann-Ostenhof, M.

    2004-01-01

    We prove that the electronic densities of atomic and molecular eigenfunctions are real analytic in R^3 away from the nuclei.......We prove that the electronic densities of atomic and molecular eigenfunctions are real analytic in R^3 away from the nuclei....

  10. Cryo-electron microscopy of vitreous sections

    International Nuclear Information System (INIS)

    Dubochet, J.; Al-Amoudi, A.; McDowall, A.W.

    2002-01-01

    Full text: For the last two decades, cryo-electron microscopy (cryo-em) of thin layers of vitrified biological suspensions has considerably extended applications in electron microscopy. Biomacromolecules or their assemblies can be observed in their fully hydrated native state, without any or few microscopy related preparation artefacts. Only electron beam damage still limits resolution, thus leaving room for specialists of image processing, capable of extracting the very last bit of information created by a limited number of electrons. They're skills and programs have been very good when applied to thin specimens but this method does not apply readily to bulk specimens. However over the last 20 years, cryo-em of vitreous bulk material and sections has also been under development. In principle, it is the dream method of structural cell biology. It consists in vitrifying a sample of tissue by rapid cooling, cutting into ultra-thin sections and cryo-em observation with all details perfectly preserved. Practically the technical problems are considerable. First of all, vitrification, which is relatively easy for sub-micron sample, must be extended to macroscopic dimensions. For this purpose, freezing under high pressure has proved very effective. Cutting a piece of vitreous material into u nder the knife . A compromise must be found between fracturing the brittle material or plastic deformation when it is more viscous. Here the recent development of an oscillating knife is promising. Finally, to become fluent with the various manipulations and adjustments leading to optimal observations requires time and experience. Copyright (2002) Australian Society for Electron Microscopy Inc

  11. Direct imaging detectors for electron microscopy

    Science.gov (United States)

    Faruqi, A. R.; McMullan, G.

    2018-01-01

    Electronic detectors used for imaging in electron microscopy are reviewed in this paper. Much of the detector technology is based on the developments in microelectronics, which have allowed the design of direct detectors with fine pixels, fast readout and which are sufficiently radiation hard for practical use. Detectors included in this review are hybrid pixel detectors, monolithic active pixel sensors based on CMOS technology and pnCCDs, which share one important feature: they are all direct imaging detectors, relying on directly converting energy in a semiconductor. Traditional methods of recording images in the electron microscope such as film and CCDs, are mentioned briefly along with a more detailed description of direct electronic detectors. Many applications benefit from the use of direct electron detectors and a few examples are mentioned in the text. In recent years one of the most dramatic advances in structural biology has been in the deployment of the new backthinned CMOS direct detectors to attain near-atomic resolution molecular structures with electron cryo-microscopy (cryo-EM). The development of direct detectors, along with a number of other parallel advances, has seen a very significant amount of new information being recorded in the images, which was not previously possible-and this forms the main emphasis of the review.

  12. 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

  13. 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

  14. 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

  15. Scanning electron microscopy of semiconductor materials

    International Nuclear Information System (INIS)

    Bresse, J.F.; Dupuy, M.

    1978-01-01

    The use of scanning electron microscopy in semiconductors opens up a large field of use. The operating modes lending themselves to the study of semiconductors are the induced current, cathodoluminescence and the use of the potential contrast which can also be applied very effectively to the study of the devices (planar in particular). However, a thorough knowledge of the mechanisms of the penetration of electrons, generation and recombination of generated carriers in a semiconductor is necessary in order to attain a better understanding of the operating modes peculiar to semiconductors [fr

  16. Scanning electron microscopy and micro-analyses

    International Nuclear Information System (INIS)

    Brisset, F.; Repoux, L.; Ruste, J.; Grillon, F.; Robaut, F.

    2008-01-01

    Scanning electron microscopy (SEM) and the related micro-analyses are involved in extremely various domains, from the academic environments to the industrial ones. The overall theoretical bases, the main technical characteristics, and some complements of information about practical usage and maintenance are developed in this book. high-vacuum and controlled-vacuum electron microscopes are thoroughly presented, as well as the last generation of EDS (energy dispersive spectrometer) and WDS (wavelength dispersive spectrometer) micro-analysers. Beside these main topics, other analysis or observation techniques are approached, such as EBSD (electron backscattering diffraction), 3-D imaging, FIB (focussed ion beams), Monte-Carlo simulations, in-situ tests etc.. This book, in French language, is the only one which treats of this subject in such an exhaustive way. It represents the actualized and totally updated version of a previous edition of 1979. It gathers the lectures given in 2006 at the summer school of Saint Martin d'Heres (France). Content: 1 - electron-matter interactions; 2 - characteristic X-radiation, Bremsstrahlung; 3 - electron guns in SEM; 4 - elements of electronic optics; 5 - vacuum techniques; 6 - detectors used in SEM; 7 - image formation and optimization in SEM; 7a - SEM practical instructions for use; 8 - controlled pressure microscopy; 8a - applications; 9 - energy selection X-spectrometers (energy dispersive spectrometers - EDS); 9a - EDS analysis; 9b - X-EDS mapping; 10 - technological aspects of WDS; 11 - processing of EDS and WDS spectra; 12 - X-microanalysis quantifying methods; 12a - quantitative WDS microanalysis of very light elements; 13 - statistics: precision and detection limits in microanalysis; 14 - analysis of stratified samples; 15 - crystallography applied to EBSD; 16 - EBSD: history, principle and applications; 16a - EBSD analysis; 17 - Monte Carlo simulation; 18 - insulating samples in SEM and X-ray microanalysis; 18a - insulating

  17. 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...

  18. Mechanisms of decoherence in electron microscopy.

    Science.gov (United States)

    Howie, A

    2011-06-01

    The understanding and where possible the minimisation of decoherence mechanisms in electron microscopy were first studied in plasmon loss, diffraction contrast images but are of even more acute relevance in high resolution TEM phase contrast imaging and electron holography. With the development of phase retrieval techniques they merit further attention particularly when their effect cannot be eliminated by currently available energy filters. The roles of electronic excitation, thermal diffuse scattering, transition radiation and bremsstrahlung are examined here not only in the specimen but also in the electron optical column. Terahertz-range aloof beam electronic excitation appears to account satisfactorily for recent observations of decoherence in electron holography. An apparent low frequency divergence can emerge for the calculated classical bremsstrahlung event probability but can be ignored for photon wavelengths exceeding the required coherence distance or path lengths in the equipment. Most bremsstrahlung event probabilities are negligibly important except possibly in large-angle bending magnets or mandolin systems. A more reliable procedure for subtracting thermal diffuse scattering from diffraction pattern intensities is proposed. Copyright © 2010 Elsevier B.V. All rights reserved.

  19. Immunogold Labeling for Scanning Electron Microscopy.

    Science.gov (United States)

    Goldberg, Martin W; Fišerová, Jindřiška

    2016-01-01

    Scanning electron microscopes are useful biological tools that can be used to image the surface of whole organisms, tissues, cells, cellular components, and macromolecules. Processes and structures that exist at surfaces can be imaged in pseudo, or real 3D at magnifications ranging from about 10× to 1,000,000×. Therefore a whole multicellular organism, such as a fly, or a single protein embedded in one of its cell membranes can be visualized. In order to identify that protein at high resolution, or to see and quantify its distribution at lower magnifications, samples can be labeled with antibodies. Any surface that can be exposed can potentially be studied in this way. Presented here is a generic method for immunogold labeling for scanning electron microscopy, using two examples of specimens: isolated nuclear envelopes and the cytoskeleton of mammalian culture cells. Various parameters for sample preparation, fixation, immunogold labeling, drying, metal coating, and imaging are discussed so that the best immunogold scanning electron microscopy results can be obtained from different types of specimens.

  20. Three-dimensional reconstruction in electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Grano, D.A.

    1979-05-01

    The development and implementation of a versatile system of image processing programs for electron microscopy is described. Both high-dose, negatively stained specimens and low-dose, unstained specimens can be analyzed by this system. The theory behind image analysis in electron microscopy is described together with the practical aspects of computer processing of electron micrographs. The Fourier transform of cylindrically symmetric objects is studied in some detail. The range of structural deductions that may be made from the Fourier transforms of projections of such objects is discussed. The methods of 2-D image filtering are applied to high-dose images of negatively stained gap junction membranes and to frozen, hydrated, low-dose images of the hexagonally packed protein component of Spirillum serpens cell wall. The computer processed Spirillum specimen reveals the presence of Y-linkers similar to those seen in negatively stained preparations. Computer processing of the gap junction images makes the presence of a central staining pit more obvious. The techniques of 3-D helical reconstruction are applied to high-dose images of negatively stained T4 bacteriophage tails, to demonstrate the successful transfer of the IBM-based MRC helical reconstruction programs to our Control Data corporation computer system. Finally, the tubular structures found in preparations of Spirillum serpens cell wall are analyzed by Fourier methods.

  1. 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...

  2. Nano, Queensland and cryo-electron microscopy

    International Nuclear Information System (INIS)

    McDowall, A.W.

    2002-01-01

    Full text: In a recent review the authors, Wolfgang Baumeister and Alasdair Steven wrote, '....there is immense opportunity for Cryo-EM, especially as boosted by merging crystallographic structures of individual subunits into moderate resolution Cryo-EM density maps of whole complexes. Electron tomography has now advanced to the point where it is a realistic goal to glimpse molecular machines operating inside cells....' This statement gives testament to the advances made over the past 25 years by many labs around the world to the area of microscopy referred to as Cryo-EM and related 3-D computing technologies. Australian scientific societies have been eager followers of this progress and heard first hand of the new developments in the field at the 1984 ACEM-8 (2). Since those early days the ACEM and other Australian/NZ societies have sponsored numerous researchers and workshops in the field of Cryo-EM to their conferences, Helin Sabil, Wah Chiu, Ron Milligan, Richard Henderson and Werner Kuhlbrandt to name only a few. These visits have stimulated a desire from Australian/NZ researchers to establish collaborations and access to prominent labs in the USA and Europe, where the means and knowledge to provide Cryo EM and 3D reconstruction technology for studying macromolecular complexes is well established. However, Australia has not been backward in seeking to provide its home research community with access to a base in biological molecular microscopy and electron crystallography technology. Since the last ACEM we have seen the emergence of a number of crucial factors, which will make the establishment of a national research facility in this field an operational reality in early 2003. Well publicized is the development of Australia's newest and perhaps most unique research institute, the institute for Molecular Bioscience (IMB) to open at the University of Queensland (UQ) in 2002. The IMB will be the platform for a new research group in advanced computational 3D

  3. 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.

  4. Electron microscopy study of advanced heterostructures for optoelectronics

    Energy Technology Data Exchange (ETDEWEB)

    Katcki, J.; Ratajczak, J.; Phillipp, F.; Muszalski, J.; Bugajski, M.; Chen, J.X.; Fiore, A

    2003-08-28

    The application of cross-sectional transmission electron microscopy and scanning electron microscopy to the investigation of optoelectronic devices are reviewed. Special attention was paid to the electron microscopy assessment of the growth perfection of such crucial elements of the devices like quantum wells, quantum dots, distributed Bragg reflectors as well as electrical contacts. Using these examples, the most important issues of the application of electron microscopy to characterization of optoelectronic devices are discussed.

  5. Characterization of high Tc materials and devices by electron microscopy

    National Research Council Canada - National Science Library

    Browning, Nigel D; Pennycook, Stephen J

    2000-01-01

    ..., and microanalysis by scanning transmission electron microscopy. Ensuing chapters examine identi®cation of new superconducting compounds, imaging of superconducting properties by lowtemperature scanning electron microscopy, imaging of vortices by electron holography and electronic structure determination by electron energy loss spectro...

  6. 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.

  7. 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...

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

    DEFF Research Database (Denmark)

    Hempel, Casper

    2017-01-01

    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....

  9. 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.

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

    Science.gov (United States)

    Müller, E; Gerthsen, D

    2017-02-01

    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 x Ga 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. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. 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.

  12. 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

  13. Electronic microscopy application in artificial minerals

    International Nuclear Information System (INIS)

    Gomez, L E.

    1995-07-01

    One of the uses of electronic microscopy in combination with the analysis microprobe EDAX is to characterize the properties of the minerals. The technique consist of studying the chemical composition by elements or by oxides of particles which can be enlarged successfully up to 100000x. With the help of the optical microscope one is able to determine the textual characteristics, the form, cleavage and other cristallographic properties which, combined with microprobe analysis enable one to determine its classification. The industrial processes which use ovens usually have problems due to the formation of impurities, spots and abnormal aspects which are reflected in a lower quality of the final material produced. These types of defects appear in minerals which are made in laboratories; knowing the natural minerals one can exercise a better quality control since this permits to know the behaviour of the raw material at a particular temperature and its reactions depending on the additives used

  14. 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

  15. 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.

  16. Advanced transmission electron microscopy on nanostructured magnetic materials

    OpenAIRE

    Campanini, Marco

    2015-01-01

    This doctoral work is focused on the study of nanostructured magnetic materials by advanced transmission electron microscopy (TEM) techniques, with emphasis on Ni2MnGa shape memory alloy thin films and magnetite nanoparticles for biomedical applications. The combination of high-resolution transmission electron microscopy and electron diffraction to characterize morphology and crystalline structure, with Lorentz microscopy and Electron Holography, permits to achieve a deep insight in the s...

  17. Proceedings of 10. Conference on Electron Microscopy of Solids

    International Nuclear Information System (INIS)

    1999-01-01

    The new technical solutions and methodical variants of electron microscopy i. e. transmission electron microscopy and scanning electron microscopy have been presented. Development of new methods and microscope constructions which became more and more sophisticated causes the progress in possible applications. The broad spectrum of such applications in metallurgy, materials science, chemical engineering, electronics, physical chemistry, solid state physics, mineralogy and other branches of science and technique have been performed and discussed at the conference

  18. 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.

  19. Analytical expressions for the electron backscattering coefficient

    International Nuclear Information System (INIS)

    August, H.J.; Wernisch, J.

    1989-01-01

    Several analytical expressions for the electron backscattering coefficient for massive homogeneous samples are compared with experimental data, directing special attention to the dependence of this quantity on the electron acceleration energy. It is shown that this dependence generally cannot be neglected. The expression proposed by Hunger and Kuechler turns out to be better than that of Love and Scott, although even the better formula can be slightly improved by a small modification. (author)

  20. Object oriented database and electronic notebook for transmission electron microscopy.

    Science.gov (United States)

    Ludtke, Steven J; Nason, Laurie; Tu, Haili; Peng, Liwei; Chiu, Wah

    2003-12-01

    As high-resolution biological transmission electron microscopy (TEM) has increased in popularity over recent years, the volume of data and number of projects underway has risen dramatically. A robust tool for effective data management is essential to efficiently process large data sets and extract maximum information from the available data. We present the Electron Microscopy Electronic Notebook (EMEN), a portable, object-oriented, web-based tool for TEM data archival and project management. EMEN has several unique features. First, the database is logically organized and annotated so multiple collaborators at different geographical locations can easily access and interpret the data without assistance. Second, the database was designed to provide flexibility to the user, so it can be used much as a lab notebook would be, while maintaining a structure suitable for data mining and direct interaction with data-processing software. Finally, as an object-oriented database, the database structure is dynamic and can be easily extended to incorporate information not defined in the original database specification.

  1. Platinum replica electron microscopy: Imaging the cytoskeleton globally and locally.

    Science.gov (United States)

    Svitkina, Tatyana M

    2017-05-01

    Structural studies reveal how smaller components of a system work together as a whole. However, combining high resolution of details with full coverage of the whole is challenging. In cell biology, light microscopy can image many cells in their entirety, but at a lower resolution, whereas electron microscopy affords very high resolution, but usually at the expense of the sample size and coverage. Structural analyses of the cytoskeleton are especially demanding, because cytoskeletal networks are unresolvable by light microscopy due to their density and intricacy, whereas their proper preservation is a challenge for electron microscopy. Platinum replica electron microscopy can uniquely bridge the gap between the "comfort zones" of light and electron microscopy by allowing high resolution imaging of the cytoskeleton throughout the entire cell and in many cells in the population. This review describes the principles and applications of platinum replica electron microscopy for studies of the cytoskeleton. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Advanced electron microscopy characterization of multimetallic nanoparticles

    Science.gov (United States)

    Khanal, Subarna Raj

    Research in noble metal nanoparticles has led to exciting progress in a versatile array of applications. For the purpose of better tailoring of nanoparticles activities and understanding the correlation between their structures and properties, control over the composition, shape, size and architecture of bimetallic and multimetallic nanomaterials plays an important role on revealing their new or enhanced functions for potentials application. Advance electron microscopy techniques were used to provide atomic scale insights into the structure-properties of different materials: PtPd, Au-Au3Cu, Cu-Pt, AgPd/Pt and AuCu/Pt nanoparticles. The objective of this work is to understand the physical and chemical properties of nanomaterials and describe synthesis, characterization, surface properties and growth mechanism of various bimetallic and multimetallic nanoparticles. The findings have provided us with novel and significant insights into the physical and chemical properties of noble metal nanoparticles. Different synthesis routes allowed us to synthesize bimetallic: Pt-Pd, Au-Au3Cu, Cu-Pt and trimetallic: AgPd/Pt, AuCu/Pt, core-shell and alloyed nanoparticles with monodispersed sizes, controlled shapes and tunable surface properties. For example, we have synthesized the polyhedral PtPd core-shell nanoparticles with octahedral, decahedral, and triangular plates. Decahedral PtPd core-shell structures are novel morphologies for this system. For the first time we fabricated that the Au core and Au3Cu alloyed shell nanoparticles passivated with CuS2 surface layers and characterized by Cs-corrected scanning transmission electron microscopy. The analysis of the high-resolution micrographs reveals that these nanoparticles have decahedral structure with shell periodicity, and that each of the particles is composed by Au core and Au3Cu ordered superlattice alloyed shell surrounded by CuS 2 surface layer. Additionally, we have described both experimental and theoretical methods of

  3. Quantitative characterization of electron detectors for transmission electron microscopy.

    Science.gov (United States)

    Ruskin, Rachel S; Yu, Zhiheng; Grigorieff, Nikolaus

    2013-12-01

    A new generation of direct electron detectors for transmission electron microscopy (TEM) promises significant improvement over previous detectors in terms of their modulation transfer function (MTF) and detective quantum efficiency (DQE). However, the performance of these new detectors needs to be carefully monitored in order to optimize imaging conditions and check for degradation over time. We have developed an easy-to-use software tool, FindDQE, to measure MTF and DQE of electron detectors using images of a microscope's built-in beam stop. Using this software, we have determined the DQE curves of four direct electron detectors currently available: the Gatan K2 Summit, the FEI Falcon I and II, and the Direct Electron DE-12, under a variety of total dose and dose rate conditions. We have additionally measured the curves for the Gatan US4000 and TVIPS TemCam-F416 scintillator-based cameras. We compare the results from our new method with published curves. Copyright © 2013 Elsevier Inc. All rights reserved.

  4. 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.

  5. The electron microscopy facility at the LNLS

    International Nuclear Information System (INIS)

    Ugarte, D.; Zanchet, D.; Silva, P.C.; Araujo, S.R. de; Bettini, J.; Gonzalez, J.C.; Nakabayashi, D.B.

    2004-01-01

    Full text: The Electron Microscopy Laboratory (LME, Lab. Microscopia Eletronica) is one of the multi user facilities of the Laboratorio Nacional de Luz Sincrotron (LNLS). It has been in operation since the beginning of 1999 to provide spatial high resolution tools, making the LNLS a unique center for advanced characterization of materials. The equipment installed at the LME can be brie y described as: a) a Low Vacuum Scanning Electron Microscope (SEM, JSM-5900LV) with microanalysis and crystallographic mapping capabilities; b) a Field Emission Gun SEM (JSM-6330F); c) a 300 kV High Resolution Transmission Electron Microscope (HRTEM, JEM 3010 URP, 1.7 A Point Res.) with TV Camera, Multi-Scan CCD Camera and X-ray Si(Li) detector; and d) a complete sample preparation laboratory for EM studies A simple procedure allows access to the LME instruments, firstly a short research project must be submitted for evaluation of viability and relevance; subsequently the training microscope sessions are scheduled. It is important to remark that EM is a routine characterization tool and the researchers have to operate the microscope by themselves; for that a training period is necessary, which may vary from 1-2 weeks for a SEM to 2-4 months for the HRTEM. Our staff addresses a great effort to the formation of human resources in order to allow inexperienced Users to become capable of acquiring and interpreting data for their research projects. Since its installation, the LME has trained more than 300 Users in EM techniques. In 2003, the number of projects developed was: 36 in the HRTEM, 16 in the FEG-SEM and 48 in the LV-SEM. This means that just the HRTEM has operated 2157 hours. The constant increase of users in addition to the more exigent EM studies being proposed indicates the necessity of an expansion of the LME by the purchase of a 200 kV FEG-TEM oriented for nano-analysis and Electron Energy Loss Spectroscopy.. (author)

  6. Recent advances in retroviruses via cryo-electron microscopy.

    Science.gov (United States)

    Mak, Johnson; de Marco, Alex

    2018-02-23

    Cryo-electron microscopy has undergone a revolution in recent years and it has contributed significantly to a number of different areas in biological research. In this manuscript, we will describe some of the recent advancements in cryo-electron microscopy focussing on the advantages that this technique can bring rather than on the technology. We will then conclude discussing how the field of retrovirology has benefited from cryo-electron microscopy.

  7. [Scanning electron microscopy of Paragonimus proliferus].

    Science.gov (United States)

    Zhou, Ben-jiang

    2005-10-30

    To identify the species of Paragonimus proliferus with scanning electron microscopy (SEM) based on the surface structure of excysted metacercariae, adult worms and eggs. Crabs were collected from the endemic area of P. proliferus and excysted metacercariae were separated. Adult worms at different ages and eggs were obtained from the experimentally infected rats. After being fixed by 2.5% glutardialdehyde and 1% osmic acid, alcohol dehydration, gilded by ion spatter, the specimens were observed under SEM by STEREOSCAN-100. The cuticular spines of excysted metacercariae distributed in single pattern, bayonet-shaped or scale-shaped. There were 6 dome-shape papillae around the rim of the ventral sucker symmetrically arranged. The cuticular spines of different age adult worms distributed in group pattern, relatively denser and more regularly arranged in the anterior part than the posterior part of the worm body. The shape and arrangement of the cuticular spines on adult worms at different ages were basically uniform. The surface of eggshell including the operculum was generally smooth. The shell rim joining the operculum was thick and prominent. A knot-like prominence was observed at the aboperculum end. The cuticular spines of both excysted metacercariae and adult worms of P. proliferus show its own characteristics, but the size and shape of the cuticular spines among individuals or different parts of the same specimen show certain differences.

  8. 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.

  9. Analytical local electron-electron interaction model potentials for atoms

    International Nuclear Information System (INIS)

    Neugebauer, Johannes; Reiher, Markus; Hinze, Juergen

    2002-01-01

    Analytical local potentials for modeling the electron-electron interaction in an atom reduce significantly the computational effort in electronic structure calculations. The development of such potentials has a long history, but some promising ideas have not yet been taken into account for further improvements. We determine a local electron-electron interaction potential akin to those suggested by Green et al. [Phys. Rev. 184, 1 (1969)], which are widely used in atom-ion scattering calculations, electron-capture processes, and electronic structure calculations. Generalized Yukawa-type model potentials are introduced. This leads, however, to shell-dependent local potentials, because the origin behavior of such potentials is different for different shells as has been explicated analytically [J. Neugebauer, M. Reiher, and J. Hinze, Phys. Rev. A 65, 032518 (2002)]. It is found that the parameters that characterize these local potentials can be interpolated and extrapolated reliably for different nuclear charges and different numbers of electrons. The analytical behavior of the corresponding localized Hartree-Fock potentials at the origin and at long distances is utilized in order to reduce the number of fit parameters. It turns out that the shell-dependent form of Green's potential, which we also derive, yields results of comparable accuracy using only one shell-dependent parameter

  10. Simultaneous First-Order Valence and Oxygen Vacancy Order/Disorder Transitions in (Pr0.85Y0.15)0.7Ca0.3CoO3-δ via Analytical Transmission Electron Microscopy.

    Science.gov (United States)

    Gulec, Ahmet; Phelan, Daniel; Leighton, Chris; Klie, Robert F

    2016-01-26

    Perovskite cobaltites have been studied for years as some of the few solids to exhibit thermally driven spin-state crossovers. The unanticipated first-order spin and electronic transitions recently discovered in Pr-based cobaltites are notably different from these conventional crossovers, and are understood in terms of a unique valence transition. In essence, the Pr valence is thought to spontaneously shift from 3+ toward 4+ on cooling, driving subsequent transitions in Co valence and electronic/magnetic properties. Here, we apply temperature-dependent transmission electron microscopy and spectroscopy to study this phenomenon, for the first time with atomic spatial resolution, in the prototypical (Pr0.85Y0.15)0.70 Ca0.30CoO3-δ. In addition to the direct spectroscopic observation of charge transfer between Pr and Co at the 165 K transition (on both the Pr and O edges), we also find a simultaneous order/disorder transition associated with O vacancies. Remarkably, the first-order valence change drives a transition between ordered and random O vacancies, at constant O vacancy density, demonstrating reversible crystallization of such vacancies even at cryogenic temperatures.

  11. 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

  12. 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

  13. Progresses in low energy electron microscopy and photoemission electron microscopy studies (LEEM and PEEM)

    International Nuclear Information System (INIS)

    Koshikawa, Takanori; Yasue, Tsuneo; Kobayashi, Keisuke; Kinoshita, Toyohiko; Ono, Kanta

    2008-02-01

    Photon factory workshop on low energy electron microscopy (LEEM) and photoemission electron microscopy (PEEM) studies was held on October 12-13, 2005. The workshop had 18 presentations and 8 contributions to the poster session with 62 attendees. The workshop started with an invitation presentation about nano-imaging and nano-spectroscopy by photoemission electron microscope using synchrotron radiation x-rays. Next two reports were about antiferromagnetic domain structure observations of a NiO(100) surface using a combined method of PEEM and soft x-ray linear dichroism. Recent development of spin SEM (scanning electron microscope) and the observation of magnetic domains of La 1.36 Sr 1.64 Mn 2 O 7 were reported. A new method for observing magnetic domain structures with SEM was developed in which the image is the result of spin polarization of secondary electrons. This method is called spin SEM. A lecture about observation of ultra-high speed phenomena by PEEM and the invitation presentation about spin dynamics in nano-scale magnetic materials attracted much attention. Structural studies of surfaces by LEEM and PEEM were actively discussed. Summaries about the measurements of Au-Si alloy island at atomic steps on Si(111), fabrication of Ga nano-dots in SiO 2 , growth of pentacene films on thin bismuth film and graphite, the surface phase transition on metal surfaces of In/Cu(001) and Sn/Cu(001), and Cu thin film growth on W(110) were also compiled in this report. Many contributions in this report were resulted from the experiments by LEEM and PEEM using SPring-8 synchrotron radiations. (Y.K.)

  14. On some aspects of high voltage electron microscopy

    International Nuclear Information System (INIS)

    Jouffrey, B.; Trinquier, J.

    1987-01-01

    The present paper deals with high voltage electron microscopy (HVEM). It is an overview on this domain due to the pionneer work of G. Dupouy which has permitted to perform a new kind of electron microscopy. Since this time, HVEM has shown its interest in high resolution, irradiations, chemical analysis, in situ experiments

  15. From electron energy-loss spectroscopy to multi-dimensional and multi-signal electron microscopy.

    Science.gov (United States)

    Colliex, Christian

    2011-01-01

    This review intends to illustrate how electron energy-loss spectroscopy (EELS) techniques in the electron microscope column have evolved over the past 60 years. Beginning as a physicist tool to measure basic excitations in solid thin foils, EELS techniques have gradually become essential for analytical purposes, nowadays pushed to the identification of individual atoms and their bonding states. The intimate combination of highly performing techniques with quite efficient computational tools for data processing and ab initio modeling has opened the way to a broad range of novel imaging modes with potential impact on many different fields. The combination of Angström-level spatial resolution with an energy resolution down to a few tenths of an electron volt in the core-loss spectral domain has paved the way to atomic-resolved elemental and bonding maps across interfaces and nanostructures. In the low-energy range, improved energy resolution has been quite efficient in recording surface plasmon maps and from them electromagnetic maps across the visible electron microscopy (EM) domain, thus bringing a new view to nanophotonics studies. Recently, spectrum imaging of the emitted photons under the primary electron beam and the spectacular introduction of time-resolved techniques down to the femtosecond time domain, have become innovative keys for the development and use of a brand new multi-dimensional and multi-signal electron microscopy.

  16. Analytical procedure for experimental quantification of carrier concentration in semiconductor devices by using electric scanning probe microscopy

    International Nuclear Information System (INIS)

    Fujita, Takaya; Matsumura, Koji; Itoh, Hiroshi; Fujita, Daisuke

    2014-01-01

    Scanning capacitance microscopy (SCM) is based on a contact-mode variant of atomic force microscopy, which is used for imaging two-dimensional carrier (electrons and holes) distributions in semiconductor devices. We introduced a method of quantification of the carrier concentration by experimentally deduced calibration curves, which were prepared for semiconductor materials such as silicon and silicon carbide. The analytical procedure was circulated to research organizations in a round-robin test. The effectiveness of the method was confirmed for practical analysis and for what is expected for industrial pre-standardization from the viewpoint of comparability among users. It was also applied to other electric scanning probe microscopy techniques such as scanning spreading resistance microscopy and scanning nonlinear dielectric microscopy. Their depth profiles of carrier concentration were found to be in good agreement with those characterized by SCM. These results suggest that our proposed method will be compatible with future next-generation microscopy. (paper)

  17. 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...

  18. 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.

  19. Graphene-enabled electron microscopy and correlated super-resolution microscopy of wet cells.

    Science.gov (United States)

    Wojcik, Michal; Hauser, Margaret; Li, Wan; Moon, Seonah; Xu, Ke

    2015-06-11

    The application of electron microscopy to hydrated biological samples has been limited by high-vacuum operating conditions. Traditional methods utilize harsh and laborious sample dehydration procedures, often leading to structural artefacts and creating difficulties for correlating results with high-resolution fluorescence microscopy. Here, we utilize graphene, a single-atom-thick carbon meshwork, as the thinnest possible impermeable and conductive membrane to protect animal cells from vacuum, thus enabling high-resolution electron microscopy of wet and untreated whole cells with exceptional ease. Our approach further allows for facile correlative super-resolution and electron microscopy of wet cells directly on the culturing substrate. In particular, individual cytoskeletal actin filaments are resolved in hydrated samples through electron microscopy and well correlated with super-resolution results.

  20. 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...

  1. Integrated Electronic Microscopy Method to Characterize BWR Crud Deposits

    International Nuclear Information System (INIS)

    Pop, Mike G.; Lockamon, Brian; Howe, James M.; Oleshko, Vladimir P.

    2007-01-01

    The primary objective of this paper is to present the best combination of analytical Electron Microscopy (EM) techniques suited for studying Boiling Water Reactor (BWR) fuel crud deposits in their 'as found' condition, for example un-adulterated portions of the deposits located in crevices at the surface of deposit. The secondary objective of the paper is to suggest a strategy to connect the analytical EM results with the Power Diffraction File (PDF-4) crystal database to ultimately explain crystal growth phenomena in crevices. The samples analyzed as part of this work were collected from steam generators in Nuclear Power Plants. These samples were selected as segregates for BWR deposits due to their similar structures and because they were freely releasable for study in the University labs. The samples were analyzed extensively through various EM techniques at magnifications up to 150,000 X. Subsequent evaluation of the analysis results demonstrated that the selected samples exhibited characteristics that were very close to second-burned fuel crud deposits from operating BWR plants. (authors)

  2. 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.

  3. A simple methodology for obtaining X-ray color images in scanning electron microscopy

    International Nuclear Information System (INIS)

    Veiga, M.M. da; Pietroluongo, L.R.V.

    1985-01-01

    A simple methodology for obtaining at least 3 elements X-ray images in only one photography is described. The fluorescent X-ray image is obtained from scanning electron microscopy with energy dispersion analysis system. The change of detector analytic channels, color cellophane foils and color films are used sequentially. (M.C.K.) [pt

  4. 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

  5. Electron microscopy localization and characterization of functionalized composite organic-inorganic SERS nanoparticles on leukemia cells

    International Nuclear Information System (INIS)

    Koh, Ai Leen; Shachaf, Catherine M.; Elchuri, Sailaja; Nolan, Garry P.; Sinclair, Robert

    2008-01-01

    We demonstrate the use of electron microscopy as a powerful characterization tool to identify and locate antibody-conjugated composite organic-inorganic nanoparticle (COINs) surface enhanced Raman scattering (SERS) nanoparticles on cells. U937 leukemia cells labeled with antibody CD54-conjugated COINs were characterized in their native, hydrated state using wet scanning electron microscopy (SEM) and in their dehydrated state using high-resolution SEM. In both cases, the backscattered electron (BSE) detector was used to detect and identify the silver constituents in COINs due to its high sensitivity to atomic number variations within a specimen. The imaging and analytical capabilities in the SEM were further complemented by higher resolution transmission electron microscopy (TEM) images and scanning Auger electron spectroscopy (AES) data to give reliable and high-resolution information about nanoparticles and their binding to cell surface antigens.

  6. 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.

  7. 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.

  8. Electron Microscopy of Ebola Virus-Infected Cells.

    Science.gov (United States)

    Noda, Takeshi

    2017-01-01

    Ebola virus (EBOV) replicates in host cells, where both viral and cellular components show morphological changes during the process of viral replication from entry to budding. These steps in the replication cycle can be studied using electron microscopy (EM), including transmission electron microscopy (TEM) and scanning electron microscopy (SEM), which is one of the most useful methods for visualizing EBOV particles and EBOV-infected cells at the ultrastructural level. This chapter describes conventional methods for EM sample preparation of cultured cells infected with EBOV.

  9. 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

  10. Electron-beam broadening in amorphous carbon films in low-energy scanning transmission electron microscopy.

    Science.gov (United States)

    Drees, H; Müller, E; Dries, M; Gerthsen, D

    2018-02-01

    Resolution in scanning transmission electron microscopy (STEM) is ultimately limited by the diameter of the electron beam. The electron beam diameter is not only determined by the properties of the condenser lens system but also by electron scattering in the specimen which leads to electron-beam broadening and degradation of the resolution with increasing specimen thickness. In this work we introduce a new method to measure electron-beam broadening which is based on STEM imaging with a multi-segmented STEM detector. We focus on STEM at low electron energies between 10 and 30 keV and use an amorphous carbon film with known thickness as test object. The experimental results are compared with calculated beam diameters using different analytical models and Monte-Carlo simulations. We find excellent agreement of the experimental data with the recently published model by Gauvin and Rudinsky [1] for small t/λ el (thickness to elastic mean free path) values which are considered in our study. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. High-resolution imaging by scanning electron microscopy of semithin sections in correlation with light microscopy.

    Science.gov (United States)

    Koga, Daisuke; Kusumi, Satoshi; Shodo, Ryusuke; Dan, Yukari; Ushiki, Tatsuo

    2015-12-01

    In this study, we introduce scanning electron microscopy (SEM) of semithin resin sections. In this technique, semithin sections were adhered on glass slides, stained with both uranyl acetate and lead citrate, and observed with a backscattered electron detector at a low accelerating voltage. As the specimens are stained in the same manner as conventional transmission electron microscopy (TEM), the contrast of SEM images of semithin sections was similar to TEM images of ultrathin sections. Using this technique, wide areas of semithin sections were also observed by SEM, without the obstruction of grids, which was inevitable for traditional TEM. This study also applied semithin section SEM to correlative light and electron microscopy. Correlative immunofluorescence microscopy and immune-SEM were performed in semithin sections of LR white resin-embedded specimens using a FluoroNanogold-labeled secondary antibody. Because LR white resin is hydrophilic and electron stable, this resin is suitable for immunostaining and SEM observation. Using correlative microscopy, the precise localization of the primary antibody was demonstrated by fluorescence microscopy and SEM. This method has great potential for studies examining the precise localization of molecules, including Golgi- and ER-associated proteins, in correlation with LM and SEM. © 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.

  12. Structure of Wet Specimens in Electron Microscopy

    Science.gov (United States)

    Parsons, D. F.

    1974-01-01

    Discussed are past work and recent advances in the use of electron microscopes for viewing structures immersed in gas and liquid. Improved environmental chambers make it possible to examine wet specimens easily. (Author/RH)

  13. 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...

  14. Photoemission electron microscopy and scanning electron microscopy of Magnetospirillum magnetotacticum’s magnetosome chains

    Energy Technology Data Exchange (ETDEWEB)

    Keutner, Christoph [Technische Univ. Dortmund, Dortmung (Germany); von Bohlen, Alex [Leibniz-Institut fur Analytische Wissenschaften, Dortmund (Germany); Berges, Ulf [Technische Univ. Dortmund, Dortmung (Germany); Espeter, Philipp [Technische Univ. Dortmund, Dortmung (Germany); Schneider, Claus M. [Peter Grunberg Institut, Julich (Germany); Westphal, Carsten [Technische Univ. Dortmund, Dortmung (Germany)

    2014-10-07

    Magnetotactic bacteria are of great interdisciplinary interest, since a vast field of applications from magnetic recording media to medical nanorobots is conceivable. A key feature for a further understanding is the detailed knowledge about the magnetosome chain within the bacteria. We report on two preparation procedures suitable for UHV experiments in reflective geometry. Further, we present the results of scanning electron microscopy, as well as the first photoemission electron microscopy experiments, both accessing the magnetosomes within intact magnetotactic bacteria and compare these to scanning electron microscopy data from the literature. From the images, we can clearly identify individual magnetosomes within their chains.

  15. 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

    subsequent hysterectomy the extent of thermal damage into the myometrium was assessed by light and electron microscopy. RESULTS: The highest temperature measured on the uterine serosa was 39.1 degrees C. Coagulation of the myometrium adjacent to the endometrium could be demonstrated by light microscopy...... 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...

  16. 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

    subsequent hysterectomy the extent of thermal damage into the myometrium was assessed by light and electron microscopy. RESULTS: The highest temperature measured on the uterine serosa was 39.1 degrees C. Coagulation of the myometrium adjacent to the endometrium could be demonstrated by light microscopy...... 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...

  17. Dysprosium disilicide nanostructures on silicon(001) studied by scanning tunneling microscopy and transmission electron microscopy

    International Nuclear Information System (INIS)

    Ye Gangfeng; Nogami, Jun; Crimp, Martin A.

    2006-01-01

    The microstructure of self-assembled dysprosium silicide nanostructures on silicon(001) has been studied by scanning tunneling microscopy and transmission electron microscopy. The studies focused on nanostructures that involve multiple atomic layers of the silicide. Cross-sectional high resolution transmission electron microscopy images and fast Fourier transform analysis showed that both hexagonal and orthorhombic/tetragonal silicide phases were present. Both the magnitude and the anisotropy of lattice mismatch between the silicide and the substrate play roles in the morphology and epitaxial growth of the nanostructures formed

  18. Atomic resolution three-dimensional electron diffraction microscopy

    International Nuclear Information System (INIS)

    Miao Jianwei; Ohsuna, Tetsu; Terasaki, Osamu; Hodgson, Keith O.; O'Keefe, Michael A.

    2002-01-01

    We report the development of a novel form of diffraction-based 3D microscopy to overcome resolution barriers inherent in high-resolution electron microscopy and tomography. By combining coherent electron diffraction with the oversampling phasing method, we show that the 3D structure of a nanocrystal can be determined ab initio at a resolution of 1 Angstrom from 29 simulated noisy diffraction patterns. This new form of microscopy can be used to image the 3D structures of nanocrystals and noncrystalline samples, with resolution limited only by the quality of sample diffraction

  19. Scanning transmission low-energy electron microscopy

    Czech Academy of Sciences Publication Activity Database

    Müllerová, Ilona; Hovorka, Miloš; Konvalina, Ivo; Unčovský, M.; Frank, Luděk

    2011-01-01

    Roč. 55, č. 4 (2011), 2:1-6 ISSN 0018-8646 R&D Projects: GA AV ČR IAA100650902; GA MŠk ED0017/01/01 Institutional research plan: CEZ:AV0Z20650511 Keywords : TEM * STEM * SEM Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 0.723, year: 2011

  20. Ultrastructure of emulsions - a comparative electron microscopy study

    DEFF Research Database (Denmark)

    Jensen, Louise Helene Søgaard

    . For this reason, electron microscopy was the method of choice. However, electron microscopy is inherently performed in vacuum and the emulsions presented a challenge by being liquid systems which are sensitiveto changes in water vapor and temperature. Furthermore, to achieve resolution and contrast of structural...... differences in specimens, electron microscopy relies on the scattering of electrons and the emulsions contain only light elements with low mass contrast. The objective of this thesis was two-fold. One was to identify and further develop sample preparation methods to enable observation of the emulsions...... is added. The Nanomega project, which is a cooperation between the National Food Institute, the Center for Electron Nanoscopy and the Department of Mechanical Engineering, all at the Technical University of Denmark, has dealt mainly with pure oil in water emulsions to describe the oxidation without...

  1. Electron microscopy of some irradiated solids

    International Nuclear Information System (INIS)

    Housseau, N.

    1985-01-01

    Are studied defects induced by ''in situ'' irradiation in a High Tension Electron Microscope (1MV) in various materials such as: metals and usual alloys for nuclear reactors, low dimensional conductors, organic conductors. The migration energy for interstitial in stainless steels is 0.8 eV for a synthetic austenitic steel and 2.0 eV for an industrial titanium steel. Irradiation damage of low dimensional compounds, TaS 2 and TaS 3 are studied as a function of temperature and irradiation dose. Modifications of surstructure diffraction spots and the progressive disappearance of ordered phases of Charge Density Wave are observed. Electron diffraction pattern of crystalline organic compouds very sensitive to irradiation are obtained at 7K. Classification according to decreaseing sensitivity is Qsub(n)-(TCNQ) 2 → TM-TSF-DM-TCNQ → TTF-TCNQ → TTT 2 I 3 [fr

  2. Transmission electron microscopy (TEM) study of minerals in coal

    Energy Technology Data Exchange (ETDEWEB)

    Hsieh, Kuang-Chien [Univ. of Illinois, Urbana-Champaign, IL (United States)

    1982-01-01

    Minerals in eight coals from different mines were characterized in the micron-size range by using analytical transmission electron microscopy. Specimens were thinned by ion-milling wafers cut from these coals; a cold stage cooled by liquid nitrogen was used to reduce thermal degradation of the minerals by the ion-beam. Different mineral compounds were observed in different coals. The major minerals are clays, sulfides, oxides, carbonates and some minor-element-bearing phosphates. Clays (kaolinite, illite and others) have been most commonly found as either flat sheets or round globules. Iron sulfide was mostly found in the No. 5 and No. 6 coals from Illinois, distributed as massive polycrystals, as clusters of single crystals (framboids) or as isolated single crystals with size range down to some 0.25 microns. Other sulfides and some oxides were found in other coals with particle size as small as some 200 angstroms. Quartz, titanium oxides and many other carbonates and phosphate compounds were also characterized. Brief TEM work in the organic mass of coal was also introduced to study the nature of the coal macerals.

  3. 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.

  4. Photon-induced near-field electron microscopy.

    Science.gov (United States)

    Barwick, Brett; Flannigan, David J; Zewail, Ahmed H

    2009-12-17

    In materials science and biology, optical near-field microscopies enable spatial resolutions beyond the diffraction limit, but they cannot provide the atomic-scale imaging capabilities of electron microscopy. Given the nature of interactions between electrons and photons, and considering their connections through nanostructures, it should be possible to achieve imaging of evanescent electromagnetic fields with electron pulses when such fields are resolved in both space (nanometre and below) and time (femtosecond). Here we report the development of photon-induced near-field electron microscopy (PINEM), and the associated phenomena. We show that the precise spatiotemporal overlap of femtosecond single-electron packets with intense optical pulses at a nanostructure (individual carbon nanotube or silver nanowire in this instance) results in the direct absorption of integer multiples of photon quanta (nhomega) by the relativistic electrons accelerated to 200 keV. By energy-filtering only those electrons resulting from this absorption, it is possible to image directly in space the near-field electric field distribution, obtain the temporal behaviour of the field on the femtosecond timescale, and map its spatial polarization dependence. We believe that the observation of the photon-induced near-field effect in ultrafast electron microscopy demonstrates the potential for many applications, including those of direct space-time imaging of localized fields at interfaces and visualization of phenomena related to photonics, plasmonics and nanostructures.

  5. 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

  6. Study of Hydrated Lime in Environmental Scanning Electron Microscopy

    Czech Academy of Sciences Publication Activity Database

    Tihlaříková, Eva; Neděla, Vilém; Rovnaníková, P.

    2013-01-01

    Roč. 19, S2 (2013), s. 1644-1645 ISSN 1431-9276 R&D Projects: GA ČR GAP102/10/1410; GA MŠk ED0017/01/01 Institutional support: RVO:68081731 Keywords : Hydrated Lime * Environmental Scanning Electron Microscopy Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 1.757, year: 2013

  7. New developments in transmission electron microscopy for nanotechnology

    International Nuclear Information System (INIS)

    Wang, Z.L.

    2003-01-01

    High-resolution transmission electron microscopy (HRTEM) is one of the most powerful tools used for characterizing nanomaterials, and it is indispensable for nanotechnology. This paper reviews some of the most recent developments in electron microscopy techniques for characterizing nanomaterials. The review covers the following areas: in-situ microscopy for studying dynamic shape transformation of nanocrystals; in-situ nanoscale property measurements on the mechanical, electrical and field emission properties of nanotubes/nanowires; environmental microscopy for direct observation of surface reactions; aberration-free angstrom-resolution imaging of light elements (such as oxygen and lithium); high-angle annular-dark-field scanning transmission electron microscopy (STEM); imaging of atom clusters with atomic resolution chemical information; electron holography of magnetic materials; and high-spatial resolution electron energy-loss spectroscopy (EELS) for nanoscale electronic and chemical analysis. It is demonstrated that the picometer-scale science provided by HRTEM is the foundation of nanometer-scale technology. (Abstract Copyright [2003], Wiley Periodicals, Inc.)

  8. 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.

  9. In situ Transmission Electron Microscopy of catalyst sintering

    DEFF Research Database (Denmark)

    DeLaRiva, Andrew T.; Hansen, Thomas Willum; Challa, Sivakumar R.

    2013-01-01

    Recent advancements in the field of electron microscopy, such as aberration correctors, have now been integrated into Environmental Transmission Electron Microscopes (TEMs), making it possible to study the behavior of supported metal catalysts under operating conditions at atomic resolution. Here......, we focus on in situ electron microscopy studies of catalysts that shed light on the mechanistic aspects of catalyst sintering. Catalyst sintering is an important mechanism for activity loss, especially for catalysts that operate at elevated temperatures. Literature from the past decade is reviewed...

  10. 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.

  11. Electron microscopy methods in studies of cultural heritage sites

    International Nuclear Information System (INIS)

    Vasiliev, A. L.; Kovalchuk, M. V.; Yatsishina, E. B.

    2016-01-01

    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.

  12. 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.

  13. Contributed Review: Review of integrated correlative light and electron microscopy

    International Nuclear Information System (INIS)

    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

  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. Sad State of Phage Electron Microscopy. Please Shoot the Messenger

    Science.gov (United States)

    Ackermann, Hans-W.

    2013-01-01

    Two hundred and sixty publications from 2007 to 2012 were classified according to the quality of electron micrographs; namely as good (71); mediocre (21); or poor (168). Publications were from 37 countries; appeared in 77 journals; and included micrographs produced with about 60 models of electron microscopes. The quality of the micrographs was not linked to any country; journal; or electron microscope. Main problems were poor contrast; positive staining; low magnification; and small image size. Unsharp images were frequent. Many phage descriptions were silent on virus purification; magnification control; even the type of electron microscope and stain used. The deterioration in phage electron microscopy can be attributed to the absence of working instructions and electron microscopy courses; incompetent authors and reviewers; and lenient journals. All these factors are able to cause a gradual lowering of standards. PMID:27694773

  16. Nanoparticle sizing: a comparative study using atomic force microscopy, transmission electron microscopy, and ferromagnetic resonance

    International Nuclear Information System (INIS)

    Lacava, L.M.; Lacava, B.M.; Azevedo, R.B.; Lacava, Z.G.M.; Buske, N.; Tronconi, A.L.; Morais, P.C.

    2001-01-01

    Atomic force microscopy (AFM), transmission electron microscopy (TEM), and ferromagnetic resonance (FMR) were used to unfold the nanoparticle size of a ferrofluid sample. Compared to TEM, the AFM method showed a nanoparticle diameter (D m ) reduction of 20% and standard deviation (σ) increase of 15%. The differences in D m and σ were associated with the AFM tip and the nanoparticle concentration on the substrate

  17. Scanning Electron Microscopy with Samples in an Electric Field

    Czech Academy of Sciences Publication Activity Database

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

    2012-01-01

    Roč. 5, č. 12 (2012), s. 2731-2756 ISSN 1996-1944 R&D Projects: GA ČR GAP108/11/2270; GA TA ČR TE01020118; GA MŠk ED0017/01/01 Institutional support: RVO:68081731 Keywords : scanning electron microscopy * slow electrons * low energy SEM * low energy STEM * cathode lens Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 2.247, year: 2012

  18. A Versatile High-Vacuum Cryo-transfer System for Cryo-microscopy and Analytics

    Science.gov (United States)

    Tacke, Sebastian; Krzyzanek, Vladislav; Nüsse, Harald; Wepf, Roger Albert; Klingauf, Jürgen; Reichelt, Rudolf

    2016-01-01

    Cryogenic microscopy methods have gained increasing popularity, as they offer an unaltered view on the architecture of biological specimens. As a prerequisite, samples must be handled under cryogenic conditions below their recrystallization temperature, and contamination during sample transfer and handling must be prevented. We present a high-vacuum cryo-transfer system that streamlines the entire handling of frozen-hydrated samples from the vitrification process to low temperature imaging for scanning transmission electron microscopy and transmission electron microscopy. A template for cryo-electron microscopy and multimodal cryo-imaging approaches with numerous sample transfer steps is presented. PMID:26910419

  19. Photon gating in four-dimensional ultrafast electron microscopy.

    Science.gov (United States)

    Hassan, Mohammed T; Liu, Haihua; Baskin, John Spencer; Zewail, Ahmed H

    2015-10-20

    Ultrafast electron microscopy (UEM) is a pivotal tool for imaging of nanoscale structural dynamics with subparticle resolution on the time scale of atomic motion. Photon-induced near-field electron microscopy (PINEM), a key UEM technique, involves the detection of electrons that have gained energy from a femtosecond optical pulse via photon-electron coupling on nanostructures. PINEM has been applied in various fields of study, from materials science to biological imaging, exploiting the unique spatial, energy, and temporal characteristics of the PINEM electrons gained by interaction with a "single" light pulse. The further potential of photon-gated PINEM electrons in probing ultrafast dynamics of matter and the optical gating of electrons by invoking a "second" optical pulse has previously been proposed and examined theoretically in our group. Here, we experimentally demonstrate this photon-gating technique, and, through diffraction, visualize the phase transition dynamics in vanadium dioxide nanoparticles. With optical gating of PINEM electrons, imaging temporal resolution was improved by a factor of 3 or better, being limited only by the optical pulse widths. This work enables the combination of the high spatial resolution of electron microscopy and the ultrafast temporal response of the optical pulses, which provides a promising approach to attain the resolution of few femtoseconds and attoseconds in UEM.

  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. Electronic tongue: An analytical gustatory tool

    Directory of Open Access Journals (Sweden)

    Rewanthwar Swathi Latha

    2012-01-01

    Full Text Available Taste is an important organoleptic property governing acceptance of products for administration through mouth. But majority of drugs available are bitter in taste. For patient acceptability and compliance, bitter taste drugs are masked by adding several flavoring agents. Thus, taste assessment is one important quality control parameter for evaluating taste-masked formulations. The primary method for the taste measurement of drug substances and formulations is by human panelists. The use of sensory panelists is very difficult and problematic in industry and this is due to the potential toxicity of drugs and subjectivity of taste panelists, problems in recruiting taste panelists, motivation and panel maintenance are significantly difficult when working with unpleasant products. Furthermore, Food and Drug Administration (FDA-unapproved molecules cannot be tested. Therefore, analytical taste-sensing multichannel sensory system called as electronic tongue (e-tongue or artificial tongue which can assess taste have been replacing the sensory panelists. Thus, e-tongue includes benefits like reducing reliance on human panel. The present review focuses on the electrochemical concepts in instrumentation, performance qualification of E-tongue, and applications in various fields.

  2. Study of titanate nanotubes by X-ray and electron diffraction and electron microscopy

    Czech Academy of Sciences Publication Activity Database

    Brunátová, T.; Popelková, Daniela; Wan, W.; Oleynikov, P.; Daniš, S.; Zou, X.; Kužel, R.

    2014-01-01

    Roč. 87, January (2014), s. 166-171 ISSN 1044-5803 Institutional support: RVO:61389013 Keywords : computer simulations * transmission electron microscopy * electron diffraction Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.845, year: 2014

  3. Simultaneous Correlative Scanning Electron and High-NA Fluorescence Microscopy

    Science.gov (United States)

    Liv, Nalan; Zonnevylle, A. Christiaan; Narvaez, Angela C.; Effting, Andries P. J.; Voorneveld, Philip W.; Lucas, Miriam S.; Hardwick, James C.; Wepf, Roger A.; Kruit, Pieter; Hoogenboom, Jacob P.

    2013-01-01

    Correlative light and electron microscopy (CLEM) is a unique method for investigating biological structure-function relations. With CLEM protein distributions visualized in fluorescence can be mapped onto the cellular ultrastructure measured with electron microscopy. Widespread application of correlative microscopy is hampered by elaborate experimental procedures related foremost to retrieving regions of interest in both modalities and/or compromises in integrated approaches. We present a novel approach to correlative microscopy, in which a high numerical aperture epi-fluorescence microscope and a scanning electron microscope illuminate the same area of a sample at the same time. This removes the need for retrieval of regions of interest leading to a drastic reduction of inspection times and the possibility for quantitative investigations of large areas and datasets with correlative microscopy. We demonstrate Simultaneous CLEM (SCLEM) analyzing cell-cell connections and membrane protrusions in whole uncoated colon adenocarcinoma cell line cells stained for actin and cortactin with AlexaFluor488. SCLEM imaging of coverglass-mounted tissue sections with both electron-dense and fluorescence staining is also shown. PMID:23409024

  4. High-resolution transmission electron microscopy of cubic Si3N4

    Science.gov (United States)

    Zhang, Ming; He, Hongliang; Xu, F. F.; Sekine, T.; Kobayashi, T.; Bando, Y.

    2000-09-01

    A cubic Si3N4 phase/nanostructure has been characterized by means of high-resolution analytical electron microscopy. The specimen prepared from β-Si3N4 powders at a high pressure and temperature by shock wave compression contained nanometer-sized Si3N4 crystallites. The results of nano-beam electron diffraction analysis and high-resolution lattice images as well as computer simulations revealed that the Si3N4 crystallites had a cubic symmetry with spinel structure. The electron energy loss spectrum suggested that the chemical compositions of these nanostructures were close to Si3N4.

  5. Comparison between direct methods for determination of microbial cell volume: electron microscopy and electronic particle sizing.

    OpenAIRE

    Montesinos, E; Esteve, I; Guerrero, R

    1983-01-01

    Size frequency distributions of different phototrophic and heterotrophic microorganisms were determined by means of scanning and transmission electron microscopy and electronic particle sizing. Statistically significant differences existed among the three techniques used in this study. Cells processed for electron microscopy showed lower mean cellular volumes than those processed for electronic particle sizing, reflecting a shrinkage by factors ranging from 1.1 to 6.2 (mean, 2.3). Processing ...

  6. Optimising electron microscopy experiment through electron optics simulation

    International Nuclear Information System (INIS)

    Kubo, Y.; Gatel, C.; Snoeck, E.; Houdellier, F.

    2017-01-01

    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. 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

  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. 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.

  10. 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.

  11. Surface properties and microporosity of polyhydroxybutyrate under scanning electron microscopy

    International Nuclear Information System (INIS)

    Raouf, A.A.; Samsudin, A.R.; Samian, R.; Akool, K.; Abdullah, N.

    2004-01-01

    This study was designed to investigate the surface properties especially surface porosity of polyhydroxybutyrate (PHB) using scanning electron microscopy. PHB granules were sprinkled on the double-sided sticky tape attached on a SEM aluminium stub and sputtered with gold (10nm thickness) in a Polaron SC515 Coater, following which the samples were placed into the SEM specimen chamber for viewing and recording. Scanning electron micrographs with different magnification of PHB surface revealed multiple pores with different sizes. (Author)

  12. Study of the niobium dehydrogenation process by transmission electron microscopy

    International Nuclear Information System (INIS)

    Bulhoes, I.A.M.; Akune, K.

    1983-01-01

    The evolution of the micro-structure of Nb-H, during the dehydrogenation process through thermal treatment, has been studied by Transmission Electron Microscopy. The results are used in order to interpret the variation of the line resolution of Electron Channeling Pattern (ECP) of Nb-H as a function of isochronous annealing temperature. It is concluded that the improvement of the ECP line resolution is enhanced of β hydrate in Nb. (Author) [pt

  13. Spatially resolved analytical electron microscopy at grain boundaries of {alpha}-Al{sub 2}O{sub 3}; Ortsaufgeloeste analytische Elektronenmikroskopie an Korngrenzen in {alpha}Al{sub 2}O{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Nufer, S.

    2001-10-01

    Aluminum oxide, {alpha}-Al{sub 2}O{sub 3}, is a common structural ceramic material. The most technologically important properties are either determined or strongly influenced by the polycrystalline microstructure. For instance, the grain boundaries control the mechanical behavior (e.g. plasticity, creep, and fracture) or various transport phenomena (e.g. ion diffusion, segregation, and electrical resistivity). In order to understand the structure-properties relationships, it is therefore important to characterize the structure and chemistry of grain boundaries, both experimentally and theoretically. In this work the electronic structure of the basal and rhombohedral twin grain boundaries and the impurity excess at different tilt grain boundaries in bicrystals were investigated, using electron energy-loss spectroscopy (EELS) and energy dispersive X-ray spectroscopy (EDXS). The electronic structure of the rhombohedral twin grain boundary was determined by comparing spatially resolved EELS measurements of the O-K ionisation edge with the theoretical density of states (DOS), obtained from local density functional theory (LDFT) calculations. The interface excess of impurities was quantitatively analysed at grain boundaries with and without Y-doping. (orig.)

  14. Quantifying Nanoscale Order in Amorphous Materials via Fluctuation Electron Microscopy

    Science.gov (United States)

    Bogle, Stephanie Nicole

    2009-01-01

    Fluctuation electron microscopy (FEM) has been used to study the nanoscale order in various amorphous materials. The method is explicitly sensitive to 3- and 4-body atomic correlation functions in amorphous materials; this is sufficient to establish the existence of structural order on the nanoscale, even when the radial distribution function…

  15. 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...

  16. A national facility for biological cryo-electron microscopy

    International Nuclear Information System (INIS)

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

    2015-01-01

    This review provides a brief update on the use of cryo-electron microscopy for integrated structural biology, along with an overview of the plans for the UK national facility for electron microscopy being built at the Diamond synchrotron. 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

  17. Scanning electron microscopy image representativeness: morphological data on nanoparticles.

    Science.gov (United States)

    Odziomek, Katarzyna; Ushizima, Daniela; Oberbek, Przemyslaw; Kurzydłowski, Krzysztof Jan; Puzyn, Tomasz; Haranczyk, Maciej

    2017-01-01

    A sample of a nanomaterial contains a distribution of nanoparticles of various shapes and/or sizes. A scanning electron microscopy image of such a sample often captures only a fragment of the morphological variety present in the sample. In order to quantitatively analyse the sample using scanning electron microscope digital images, and, in particular, to derive numerical representations of the sample morphology, image content has to be assessed. In this work, we present a framework for extracting morphological information contained in scanning electron microscopy images using computer vision algorithms, and for converting them into numerical particle descriptors. We explore the concept of image representativeness and provide a set of protocols for selecting optimal scanning electron microscopy images as well as determining the smallest representative image set for each of the morphological features. We demonstrate the practical aspects of our methodology by investigating tricalcium phosphate, Ca 3 (PO 4 ) 2 , and calcium hydroxyphosphate, Ca 5 (PO 4 ) 3 (OH), both naturally occurring minerals with a wide range of biomedical applications. © 2016 The Authors Journal of Microscopy © 2016 Royal Microscopical Society.

  18. The structure of spinach Photosystem I studied by electron microscopy

    NARCIS (Netherlands)

    Boekema, Egbert J.; Wynn, R. Max; Malkin, Richard

    1990-01-01

    The structure of three types of Photosystem I (PS I) complex isolated from spinach chloroplasts was studied by electron microscopy and computer image analysis. Molecular projections (top views and side views) of a native PS I complex (PSI-200), an antenna-depleted PS I complex (PSI-100) and the PS I

  19. 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....

  20. 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

  1. 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…

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

    African Journals Online (AJOL)

    Results suggest that the SEM-EDX is one of the potential tools for rapid detection of metals, namely, As and Cd in himematsutake. Key words: Arsenic (As), cadmium (Cd), scanning electron microscopy-energy dispersive X-ray spectrometer (SEM-EDX), coupled plasma-mass spectrometer (ICP-MS), himematsutake.

  3. 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.

  4. 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...

  5. Optimising electron microscopy experiment through electron optics simulation.

    Science.gov (United States)

    Kubo, Y; Gatel, C; Snoeck, E; Houdellier, F

    2017-04-01

    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 300kV 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. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. 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...

  7. Seeing in 4D with electrons: development of ultrafast electron microscopy at Caltech

    International Nuclear Information System (INIS)

    Baskin, J.S.; Zewail, A.H.

    2014-01-01

    The vision to develop 4D electron microscopy, a union of the capabilities of electron microscopy with ultrafast techniques to capture clearly defined images of the nano-scale structure of a material at each step in the course of its chemical or physical transformations, has been pursued at Caltech for the last decade. In this contribution, we will give a brief overview of the capabilities of three currently active Caltech 4D microscopy laboratories. Ongoing work is illustrated by a description of the most recent application of photon-induced near-field electron microscopy (PINEM), a field made possible only by the development of the 4D ultrafast electron microscopy (UEM). An appendix gives the various applications made so far and the historic roots of the development at Caltech. (authors)

  8. 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.

  9. Very low energy scanning electron microscopy in nanotechnology

    Czech Academy of Sciences Publication Activity Database

    Müllerová, Ilona; Hovorka, Miloš; Mika, Filip; Mikmeková, Eliška; Mikmeková, Šárka; Pokorná, Zuzana; Frank, Luděk

    2012-01-01

    Roč. 9, 8/9 (2012), s. 695-716 ISSN 1475-7435 R&D Projects: GA MŠk OE08012; GA MŠk ED0017/01/01; GA AV ČR IAA100650902 Institutional research plan: CEZ:AV0Z20650511 Keywords : scanning electron microscopy * very low energy electrons * cathode lens * grain contrast * strain contrast * imaging of participates * dopant contrast * very low energy STEM * graphene Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 1.087, year: 2012

  10. Diagnostic electron microscopy of head and neck tumors.

    Science.gov (United States)

    Regezi, J A; Batsakis, J C

    1978-01-01

    One hundred sixty-one neoplasms from the region of the head and neck were studied by electron microscopy to define (1) subcellular structures important of essential to diagnosis, and (2) the application and/or limitations of fresh, formaldehyde-fixed, and paraffin-blocked tissues for diagnostic use. It was concluded that electron microscopical identification of specific cytoplasmic structures was helpful in the diagnosis of head and neck neoplasms, especially those that were equivocal at the light microscopical level. Although electron microscopy could permit a more accurate classification of neoplasms in many cases, it was of little value in separating benign from malignant lesions. It was also concluded that formaldehyde-fixed tissue was a reliable source of material for these studies. Paraffin-embedded tissue was much more limited.

  11. Effective cellulose nanocrystal imaging using transmission electron microscopy.

    Science.gov (United States)

    Stinson-Bagby, Kelly L; Roberts, Rose; Foster, E Johan

    2018-04-15

    Characterization of cellulose nanocrystals (CNCs) is often complex and tedious. With their increased use for biological materials, polymer reinforcing agents, and other applications, better characterization methods of CNCs are needed to ensure product quality. However, because of their small size, hydrogen bonding, and low electron density, individual CNCs are difficult to image with high resolution and magnification using electron microscopy. Methods to help counter these challenges include staining for increased contrast and techniques to increase dispersion. This work tested several stains, dispersing agents, and sample supports to find a consistent method of individualizing CNCs and providing good contrast for imaging in transmission electron microscopy (TEM). The most consistent method found uses a low concentration of CNCs, bovine serum albumin as a dispersing agent, and Nanovan ® as the contrasting stain on a silicon monoxide-coated Formvar TEM grid. Copyright © 2018 Elsevier Ltd. All rights reserved.

  12. The art in science: electron microscopy and paintings conservation

    International Nuclear Information System (INIS)

    Waters, L.

    2003-01-01

    Full text: When examining a painting, a conservator uses many different and complementary methods of analysis to build an understanding of the materials and way the painting was constructed. Common methods of examination include x-radiography, infrared reflectography, ultraviolet fluorescence and optical microscopy of the surface of the painting. Minute samples of paint prepared as cross-sections are sometimes taken for optical examination under the microscope, and it is these that can, conveniently, be further analysed with electron microscopy to yield another level of information. Electron microscopy has a valuable role to play within the examination of paintings, be it for pigment identification alone, or at the other end of the spectrum, for informing issues around the attribution of works of art. This paper provides an overview of the use of electron microscopy in the conservation of paintings by discussing examples of work undertaken by the National Gallery of Victoria and the CSIRO. Work described includes the problem of distinguishing between restorers' original paint in a landscape by Arthur Streeton, and the examination of the ground or priming layer in a Rembrandt portrait which clarified its attribution to his studio. Copyright (2003) Australian Microbeam Analysis Society

  13. 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.

  14. Electron transparent graphene windows for environmental scanning electron microscopy in liquids and dense gases.

    Science.gov (United States)

    Stoll, Joshua D; Kolmakov, Andrei

    2012-12-21

    Due to its ultrahigh electron transmissivity in a wide electron energy range, molecular impermeability, high electrical conductivity and excellent mechanical stiffness, suspended graphene membranes appear to be a nearly ideal window material for in situ (in vivo) environmental electron microscopy of nano- and mesoscopic objects (including bio-medical samples) immersed in liquids and/or in dense gaseous media. In this paper, taking advantage of a small modification of the graphene transfer protocol onto metallic and SiN supporting orifices, reusable environmental cells with exchangeable graphene windows have been designed. Using colloidal gold nanoparticles (50 nm) dispersed in water as model objects for scanning electron microscopy in liquids as proof of concept, different conditions for imaging through the graphene membrane were tested. Limiting factors for electron microscopy in liquids, such as electron beam induced water radiolysis and damage of the graphene membrane at high electron doses, are discussed.

  15. Electron transparent graphene windows for environmental scanning electron microscopy in liquids and dense gases

    International Nuclear Information System (INIS)

    Stoll, Joshua D; Kolmakov, Andrei

    2012-01-01

    Due to its ultrahigh electron transmissivity in a wide electron energy range, molecular impermeability, high electrical conductivity and excellent mechanical stiffness, suspended graphene membranes appear to be a nearly ideal window material for in situ (in vivo) environmental electron microscopy of nano- and mesoscopic objects (including bio-medical samples) immersed in liquids and/or in dense gaseous media. In this paper, taking advantage of a small modification of the graphene transfer protocol onto metallic and SiN supporting orifices, reusable environmental cells with exchangeable graphene windows have been designed. Using colloidal gold nanoparticles (50 nm) dispersed in water as model objects for scanning electron microscopy in liquids as proof of concept, different conditions for imaging through the graphene membrane were tested. Limiting factors for electron microscopy in liquids, such as electron beam induced water radiolysis and damage of the graphene membrane at high electron doses, are discussed. (paper)

  16. Environmental Transmission Electron Microscopy of catalysts for the methanol synthesis

    DEFF Research Database (Denmark)

    Duchstein, Linus Daniel Leonhard

    Ga. Both were synthesized from Cu and Ni nitrate salts as well as Ni and Ga nitrates salts. Both systems got catalytically tested and investigated by in-situ X-Ray Diffraction (XRD) and Environmental Transmission Electron Microscopy (ETEM). It was possible to follow the synthesis of the catalysts......Ni forms a substitutional alloy. During the reaction and artificial ageing a deactivation of the NiGa due to a phase change could be observed. CuNialso changes the the oxidation state during the reaction. Furthermore the influence of the electron beam on the catalytic systems during exposure to gas...... atmosphere and temperature was investigated. CuNi was exposed to the electron beam for 3 different intensities and 3 different temperatures while the oxidation state of the Cu2+ was measured by energy electron loss spectroscopy. It turns out that the electron beam does have an influence but it does not seem...

  17. Transmission scanning electron microscopy: Defect observations and image simulations.

    Science.gov (United States)

    Callahan, Patrick G; Stinville, Jean-Charles; Yao, Eric R; Echlin, McLean P; Titus, Michael S; De Graef, Marc; Gianola, Daniel S; Pollock, Tresa M

    2018-03-01

    The new capabilities of a FEG scanning electron microscope (SEM) equipped with a scanning transmission electron microscopy (STEM) detector for defect characterization have been studied in parallel with transmission electron microscopy (TEM) imaging. Stacking faults and dislocations have been characterized in strontium titanate, a polycrystalline nickel-base superalloy and a single crystal cobalt-base material. Imaging modes that are similar to conventional TEM (CTEM) bright field (BF) and dark field (DF) and STEM are explored, and some of the differences due to the different accelerating voltages highlighted. Defect images have been simulated for the transmission scanning electron microscopy (TSEM) configuration using a scattering matrix formulation, and diffraction contrast in the SEM is discussed in comparison to TEM. Interference effects associated with conventional TEM, such as thickness fringes and bending contours are significantly reduced in TSEM by using a convergent probe, similar to a STEM imaging modality, enabling individual defects to be imaged clearly even in high dislocation density regions. Beyond this, TSEM provides significant advantages for high throughput and dynamic in-situ characterization. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Human enamel structure studied by high resolution electron microscopy

    International Nuclear Information System (INIS)

    Wen, S.L.

    1989-01-01

    Human enamel structural features are characterized by high resolution electron microscopy. The human enamel consists of polycrystals with a structure similar to Ca10(PO4)6(OH)2. This article describes the structural features of human enamel crystal at atomic and nanometer level. Besides the structural description, a great number of high resolution images are included. Research into the carious process in human enamel is very important for human beings. This article firstly describes the initiation of caries in enamel crystal at atomic and unit-cell level and secondly describes the further steps of caries with structural and chemical demineralization. The demineralization in fact, is the origin of caries in human enamel. The remineralization of carious areas in human enamel has drawn more and more attention as its potential application is realized. This process has been revealed by high resolution electron microscopy in detail in this article. On the other hand, the radiation effects on the structure of human enamel are also characterized by high resolution electron microscopy. In order to reveal this phenomenon clearly, a great number of electron micrographs have been shown, and a physical mechanism is proposed. 26 references

  19. 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

  20. Scanning electron microscopy and micro-analyses; Microscopie electronique a balayage et microanalyses

    Energy Technology Data Exchange (ETDEWEB)

    Brisset, F.; Repoux, L.; Ruste, J.; Grillon, F.; Robaut, F

    2008-07-01

    Scanning electron microscopy (SEM) and the related micro-analyses are involved in extremely various domains, from the academic environments to the industrial ones. The overall theoretical bases, the main technical characteristics, and some complements of information about practical usage and maintenance are developed in this book. high-vacuum and controlled-vacuum electron microscopes are thoroughly presented, as well as the last generation of EDS (energy dispersive spectrometer) and WDS (wavelength dispersive spectrometer) micro-analysers. Beside these main topics, other analysis or observation techniques are approached, such as EBSD (electron backscattering diffraction), 3-D imaging, FIB (focussed ion beams), Monte-Carlo simulations, in-situ tests etc.. This book, in French language, is the only one which treats of this subject in such an exhaustive way. It represents the actualized and totally updated version of a previous edition of 1979. It gathers the lectures given in 2006 at the summer school of Saint Martin d'Heres (France). Content: 1 - electron-matter interactions; 2 - characteristic X-radiation, Bremsstrahlung; 3 - electron guns in SEM; 4 - elements of electronic optics; 5 - vacuum techniques; 6 - detectors used in SEM; 7 - image formation and optimization in SEM; 7a - SEM practical instructions for use; 8 - controlled pressure microscopy; 8a - applications; 9 - energy selection X-spectrometers (energy dispersive spectrometers - EDS); 9a - EDS analysis; 9b - X-EDS mapping; 10 - technological aspects of WDS; 11 - processing of EDS and WDS spectra; 12 - X-microanalysis quantifying methods; 12a - quantitative WDS microanalysis of very light elements; 13 - statistics: precision and detection limits in microanalysis; 14 - analysis of stratified samples; 15 - crystallography applied to EBSD; 16 - EBSD: history, principle and applications; 16a - EBSD analysis; 17 - Monte Carlo simulation; 18 - insulating samples in SEM and X-ray microanalysis; 18a

  1. 35 years of electron microscopy in Costa Rica

    International Nuclear Information System (INIS)

    Hernandez Chavarria, Francisco

    2011-01-01

    Electron microscopy has celebrated in 2009 the XXXV anniversary in Costa Rica. The history of the electron microscopy was initiated with the donation of a microscope by Japan and the establishment of the Unidad de Microscopia Electronica (UME), which later, has been consolidated as the Centro de Investigacion en Estructuras Microscopicas (CIEMic) of the Universidad de Costa Rica (UCR). This center has realized its own research and has gave support to different units of the UCR, state universities and the private sector. Currently, the CIEMic has had two transmission electron microscopes (TEM) and two scanning electron microscopes (SEM), besides of optical microscopy equipment, including a laser confocal microscope. The two fundamental types of electron microscopes (TEM and SEM) have generated different images. While the first has had a resolution that has allowed to analyze virus, usually their images have been flat; however, with some special techniques can obtain three-dimensional images. The image in the TEM is generated by electrons that have passed through the sample, and to interact with its atoms have changed its energy and trajectory. This, at the end, has impacted on a photosensitive screen that has become in flashes, whose intensity has depended on its energy and form the image. Meanwhile, in the MER, the image has been normal type, although with less resolution. The electrons in the MER are focused on a small area of the sample in which have interacted with the atoms of this, and has generated a a series of signals, including the most used were the secondary electrons and characteristic X-rays. In both cases, an electron from beam has generated in the filament a collision against an electron of the sample and has given part of its energy to the degree of release of its atom and issued out of the sample; this has been called secondary electrons. X-rays have been generated when an electron of the same atom that has lost the secondary electron, but in an

  2. 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.

  3. Microfabricated high-bandpass foucault aperture for electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    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.

  4. Combined time-lapse cinematography and immuno-electron microscopy.

    Science.gov (United States)

    Balfour, B M; Goscicka, T; MacKenzie, J L; Gautam, A; Tate, M; Clark, J

    1990-04-01

    A method was developed to record interactions between mobile non-adherent immunocytes by time-lapse cinematography and then to study the same cells by immuno-electron microscopy, using monoclonal antibodies against surface components. For this purpose a modified stage was designed to fit an inverted microscope. The attachment included a device to cool the culture chamber with N2 gas, a micro-injector for monoclonal antibody and immuno-gold treatment, and two pairs of washing needles to change the medium without disturbance. The technique was first employed to study the formation of aggregates around the antigen-presenting cells in cultures containing cells from hyper-immunized animals. Recently peripheral blood cells from normal subjects and patients with immune deficiency syndromes were stimulated with pokeweed mitogen, cluster formation was recorded, and the cells were processed for immuno-electron microscopy.

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

    Science.gov (United States)

    Picher, Matthieu; Mazzucco, Stefano; Blankenship, Steve; Sharma, Renu

    2015-03-01

    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. Published by Elsevier B.V.

  6. Atomic-level Electron Microscopy of Metal and Alloy Electrocatalysts

    DEFF Research Database (Denmark)

    Deiana, Davide

    This thesis presents the application of transmission electron microscopy techniques towards the characterisation of novel metal nanoparticle catalysts. Two main subjects have been covered: first, the sintering-resistance behaviour of monomodal mass-selected Pt cluster catalysts have been studied...... flat surfaces and exposed to different sintering conditions. Ex situ STEM imaging has been used to monitor the variation of the particle dimensions through the analysis of particle area distributions. Clusters with a monomodal size distribution exhibited intrinsic sintering resistance on different...... peroxide H2O2. The active surface is predicted to be formed by reactive Pt or Pd atoms surrounded by more inert Hg atoms. Electrochemical measurements on the two catalysts have shown performance exceeding the current state-of-the-art in both forms of extended surface and nanoparticles. Electron microscopy...

  7. 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.

  8. In situ transmission electron microscopy for magnetic nanostructures

    DEFF Research Database (Denmark)

    Ngo, Duc-The; Kuhn, Luise Theil

    2016-01-01

    Nanomagnetism is a subject of great interest because of both application and fundamental aspects in which understanding of the physical and electromagnetic structure of magnetic nanostructures is essential to explore the magnetic properties. Transmission electron microscopy (TEM) is a powerful tool...... that allows understanding of both physical structure and micromagnetic structure of the thin samples at nanoscale. Among TEM techniques, in situ TEM is the state-of-the-art approach for imaging such structures in dynamic experiments, reconstructing a real-time nanoscale picture of the properties......-structure correlation. This paper aims at reviewing and discussing in situ TEM magnetic imaging studies, including Lorentz microscopy and electron holography in TEM, applied to the research of magnetic nanostructures....

  9. Practical aspects of monochromators developed for transmission electron microscopy

    Science.gov (United States)

    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 imaging, such as spatial or angular chromaticity, are also discussed. PMID:25125333

  10. Demonstration of Polysaccharide Capsule in Campylobacter jejuni Using Electron Microscopy

    OpenAIRE

    Karlyshev, Andrey V.; McCrossan, Maria V.; Wren, Brendan W.

    2001-01-01

    Recently, we reported that Campylobacter jejuni, an important gastrointestinal pathogen, has the genetic determinants to produce a capsular polysaccharide (Karlyshev et al., Mol. Microbiol. 35:529–541, 2000). Despite these data, the presence of a capsule in these bacteria has remained controversial. In this study we stain C. jejuni cells with the cationic dye Alcian blue and demonstrate for the first time by electron microscopy that C. jejuni cells produce a polysaccharide capsule that is ret...

  11. Watershed Merge Tree Classification for Electron Microscopy Image Segmentation

    OpenAIRE

    Liu, Ting; Jurrus, Elizabeth; Seyedhosseini, Mojtaba; Ellisman, Mark; Tasdizen, Tolga

    2012-01-01

    Automated segmentation of electron microscopy (EM) images is a challenging problem. In this paper, we present a novel method that utilizes a hierarchical structure and boundary classification for 2D neuron segmentation. With a membrane detection probability map, a watershed merge tree is built for the representation of hierarchical region merging from the watershed algorithm. A boundary classifier is learned with non-local image features to predict each potential merge in the tree, upon which...

  12. Image formation and image analysis in electron microscopy

    International Nuclear Information System (INIS)

    Heel, M. van.

    1981-01-01

    This thesis covers various aspects of image formation and image analysis in electron microscopy. The imaging of relatively strong objects in partially coherent illumination, the coherence properties of thermionic emission sources and the detection of objects in quantum noise limited images are considered. IMAGIC, a fast, flexible and friendly image analysis software package is described. Intelligent averaging of molecular images is discussed. (C.F.)

  13. Cross-sectional transmission electron microscopy of semiconductors

    International Nuclear Information System (INIS)

    Sadana, D.K.

    1982-10-01

    A method to prepare cross-sectional (X) semiconductor specimens for transmission electron microscopy (TEM) has been described. The power and utility of XTEM has been demonstrated. It has been shown that accuracy and interpretation of indirect structural-defects profiling techniques, namely, MeV He + channeling and secondary ion mass spectrometry (SIMS) can be greatly enhanced by comparing their results with those obtained by XTEM from the same set of samples

  14. Application of Colloidal Palladium Nanoparticles for Labeling in Electron Microscopy

    Czech Academy of Sciences Publication Activity Database

    Vancová, Marie; Šlouf, Miroslav; Langhans, Jan; Pavlová, Eva; Nebesářová, Jana

    2011-01-01

    Roč. 17, č. 5 (2011), s. 810-816 ISSN 1431-9276 R&D Projects: GA AV ČR KAN200520704; GA AV ČR KJB600960906; GA ČR GAP205/10/0348 Institutional research plan: CEZ:AV0Z60220518; CEZ:AV0Z40500505 Keywords : electron microscopy * colloidal palladium * nanoparticles * labeling * salivary glands * Ixodes ricinus Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.007, year: 2011

  15. 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.

  16. 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...

  17. Characterization of chiral mesoporous materials by transmission electron microscopy.

    Science.gov (United States)

    Ohsuna, Tetsu; Liu, Zheng; Che, Shunai; Terasaki, Osamu

    2005-02-01

    By using transmission electron microscopy (TEM), the chirality of novel mesoporous materials has been studied. In addition, a computer simulation that uses a simple structural model was employed. The existence of chiral channels inside a tubelike material was confirmed by the observation of fringes along the length of the tubes. The chiral pitch of the channels was measured from the intermittent period, the chirality (right- or left-handed) was determined from the tilt direction of a tube compared with the direction of incident electrons and the curvature direction of the curved intermitted fringes as viewed in the TEM images.

  18. Electron microscopy and plastic deformation of HCP metals and alloys

    International Nuclear Information System (INIS)

    Poirier, J.-P.; Le Hazif, Roger

    1976-01-01

    The recent literature on the slip systems of the h.c.p. metals is reviewed and the contribution of transmission electron microscopy assessed. It is now clear that the stress-strain curves and the dislocation configurations in the slip plane are very similar, whether the principal slip system is basal or prismatic. The important problem of the relative ease of slip systems is linked to the ease of splitting of dislocations in the slip planes and to the electronic band structure of the metal [fr

  19. In Situ Scanning Probe Microscopy and New Perspectives in Analytical Chemistry

    DEFF Research Database (Denmark)

    Andersen, Jens Enevold Thaulov; Zhang, Jingdong; Chi, Qijin

    1999-01-01

    The resolution of scanning probe microscopies is unpresedented but the techniques are fraught with limitations as analytical tools. These limitations and their relationship to the physical mechanisms of image contrast are first discussed. Some new options based on in situ STM, which hold prospect...

  20. Environmental Transmission Electron Microscopy in an Aberration-Corrected Environment

    DEFF Research Database (Denmark)

    Hansen, Thomas W.; Wagner, Jakob B.

    2012-01-01

    The increasing use of environmental transmission electron microscopy (ETEM) in materials science provides exciting new possibilities for investigating chemical reactions and understanding both the interaction of fast electrons with gas molecules and the effect of the presence of gas on high......-resolution imaging. A gaseous atmosphere in the pole-piece gap of the objective lens of the microscope alters both the incoming electron wave prior to interaction with the sample and the outgoing wave below the sample. Whereas conventional TEM samples are usually thin (below 100 nm), the gas in the environmental...... cell fills the entire gap between the pole pieces and is thus not spatially localized. By using an FEI Titan environmental transmission electron microscope equipped with a monochromator and an aberration corrector on the objective lens, we have investigated the effects on imaging and spectroscopy...

  1. 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.

  2. Experiments in electron microscopy: from metals to nerves

    International Nuclear Information System (INIS)

    Unwin, Nigel

    2015-01-01

    Electron microscopy has advanced remarkably as a tool for biological structure research since the development of methods to examine radiation-sensitive unstained specimens and the introduction of cryo-techniques. Structures of biological molecules at near-atomic resolution can now be obtained from images of single particles as well as crystalline arrays. It has also become possible to analyze structures of molecules in their functional context, i.e. in their natural membrane or cellular setting, and in an ionic environment like that in living tissue. Electron microscopy is thus opening ways to answer definitively questions about physiological mechanisms. Here I recall a number of experiments contributing to, and benefiting from the technical advances that have taken place. I begin—in the spirit of this crystallography series—with some biographical background, and then sketch the path to an analysis by time-resolved microscopy of the opening mechanism of an ion channel (nicotinic acetylcholine receptor). This analysis illustrates how electron imaging can be combined with freeze-trapping to illuminate a transient biological event: in our case, chemical-to-electrical transduction at the nerve-muscle synapse. (invited comment)

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

    Energy Technology Data Exchange (ETDEWEB)

    Matthews, D.T.A.; Ocelik, V.; Bronsveld, P.M. [Department of Applied Physics, Netherlands Institute for Metals Research and Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG Groningen (Netherlands); De Hosson, J.Th.M. [Department of Applied Physics, Netherlands Institute for Metals Research and Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG Groningen (Netherlands)], E-mail: j.t.m.de.hosson@rug.nl

    2008-05-15

    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 tensile fracture of metallic glasses to be analysed. In situ shear band propagation was found to be jump-like, with the jump sites correlating with the formation of secondary shear bands. The effect of structural relaxation by in situ heating is also discussed. Nanocrystallization near the fracture surface was observed; however, no crystallization was also reported in the same sample and the reasons for this are discussed. Both the TEM and the SEM observations confirmed the presence of a liquid-like layer on or near the fracture surface of the ribbons. The formation of a liquid-like layer was characterized by the vein geometries and vein densities on the fracture surfaces and its dependence on shear displacement, {delta}, is discussed. A simple model is adapted to relate the temperature rise during shear banding to the glass transition and melting temperatures and this is used to explain the variety of fracture surfaces which are developed for macroscopically identical tensile testing of metallic glasses together with features which exhibit local melting.

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

    International Nuclear Information System (INIS)

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

    2008-01-01

    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 tensile fracture of metallic glasses to be analysed. In situ shear band propagation was found to be jump-like, with the jump sites correlating with the formation of secondary shear bands. The effect of structural relaxation by in situ heating is also discussed. Nanocrystallization near the fracture surface was observed; however, no crystallization was also reported in the same sample and the reasons for this are discussed. Both the TEM and the SEM observations confirmed the presence of a liquid-like layer on or near the fracture surface of the ribbons. The formation of a liquid-like layer was characterized by the vein geometries and vein densities on the fracture surfaces and its dependence on shear displacement, δ, is discussed. A simple model is adapted to relate the temperature rise during shear banding to the glass transition and melting temperatures and this is used to explain the variety of fracture surfaces which are developed for macroscopically identical tensile testing of metallic glasses together with features which exhibit local melting

  5. A Versatile High-Vacuum Cryo-transfer System for Cryo-microscopy and Analytics

    Czech Academy of Sciences Publication Activity Database

    Tacke, S.; Krzyžánek, Vladislav; Nüsse, H.; Wepf, R.A.; Klingauf, J.; Reichelt, R.

    2016-01-01

    Roč. 110, č. 4 (2016), s. 758-765 ISSN 0006-3495 R&D Projects: GA ČR(CZ) GA14-20012S Institutional support: RVO:68081731 Keywords : transmission electron microscopy * cryoelectron tomography * cells Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 3.656, year: 2016

  6. Analytical Schwartz density applied to heavy two-electron ions

    Energy Technology Data Exchange (ETDEWEB)

    Romera, E.; Dehesa, J.S. [Universidad de Granada (Spain); Koga, Toshikatsu [Muroran Institute of Technology (Japan)

    1997-01-20

    An analytical expression of the electron density function p(r) due to Schwartz for two-electron atomic systems is applied to a detailed study of density-dependent properties of relatively heavy two-electron ions. Comparison of the Schwartz results with those from accurate Hartree-Fock and Hylleraas wave functions shows that despite its simple yet analytical form, the Schwartz density has a quantitative applicability in the density study of two-electron atoms within the nonrelativistic framework. 13 refs., 4 tabs.

  7. Electron microscopy study of antioxidant interaction with bacterial cells

    Science.gov (United States)

    Plotnikov, Oleg P.; Novikova, Olga V.; Konnov, Nikolai P.; Korsukov, Vladimir N.; Gunkin, Ivan F.; Volkov, Uryi P.

    2000-10-01

    To maintain native microorganisms genotype and phenotype features a lyophylization technique is widely used. However in this case cells are affected by influences of vacuum and low temperature that cause a part of the cells population to be destruction. Another factor reduced microorganisms vitality is formation of reactive oxygen forms that damage certain biological targets (such as DNA, membranes etc.) Recently to raise microorganism's resistance against adverse condition natural and synthetic antioxidants are used. Antioxidant- are antagonists of free radicals. Introduction of antioxidants in protective medium for lyophylization increase bacteria storage life about 2,0-4,8 fold in comparison with reference samples. In the article the main results of our investigation of antioxidants interaction with microorganism cells is described. As bacteria cells we use vaccine strain yersinia pestis EV, that were grown for 48 h at 28 degree(s)C on the Hottinger agar (pH 7,2). Antioxidants are inserted on the agar surface in specimen under test. To investigate a localization of antioxidants for electron microscopy investigation, thallium organic antioxidants were used. The thallium organic compounds have an antioxidant features if thallium is in low concentration (about 1(mu) g/ml). The localization of the thallium organic antioxidants on bacteria Y. pestis EV is visible in electron microscopy images, thallium being heavy metal with high electron density. The negatively stained bacteria and bacteria thin sections with thallium organic compounds were investigated by means of transmission electron microscopy. The localization of the thallium organic compounds is clearly visible in electron micrographs as small dark spots with size about 10-80nm. Probably mechanisms of interaction of antioxidants with bacteria cells are discussed.

  8. 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.

  9. Determination of lead in clay enameled by X-ray fluorescence technique in Total reflection and by Scanning Electron Microscopy

    International Nuclear Information System (INIS)

    Zarazua O, G.; Carapia M, L.

    2000-01-01

    This work has the objective of determining lead free in the glazed commercial stewing pans using the X-ray fluorescence technique in Total reflection (FRX) and the observation and semiquantitative determination of lead by Analytical Scanning Electron Microscopy (ASEM). (Author)

  10. Stereoscopic and photometric surface reconstruction in scanning electron microscopy

    International Nuclear Information System (INIS)

    Scherer, S.

    2000-01-01

    The scanning electron microscope (SEM) is one of the most important devices to examine microscopic structures as it offers images of a high contrast range with a large depth of focus. Nevertheless, three-dimensional measurements, as desired in fracture mechanics, have previously not been accomplished. This work presents a system for automatic, robust and dense surface reconstruction in scanning electron microscopy combining new approaches in shape from stereo and shape from photometric stereo. The basic theoretical assumption for a known adaptive window algorithm is shown not to hold in scanning electron microscopy. A constraint derived from this observation yields a new, simplified, hence faster calculation of the adaptive window. The correlation measure itself is obtained by a new ordinal measure coefficient. Shape from photometric stereo in the SEM is formulated by relating the image formation process with conventional photography. An iterative photometric ratio reconstruction is invented based on photometric ratios of backscatter electron images. The performance of the proposed system is evaluated using ground truth data obtained by three alternative shape recovery devices. Most experiments showed relative height accuracy within the tolerances of the alternative devices. (author)

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

    Science.gov (United States)

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

    2018-03-28

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

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

    International Nuclear Information System (INIS)

    Tong Yongpeng; Li Changming; Liang Feng; Chen Jianmin; Zhang Hong; Liu Guoqing; Sun Huibin; Luong, John H.T.

    2008-01-01

    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 2 O 3 and TiO 2 ) on a T lymphoblastic leukemia Jurkat cell line. The increased calcium ion (from CaCl 2 ) in the culture medium stimulated the accumulation of BaP and EB inside the cell, leading to cell death. ZnO, Al 2 O 3 and TiO 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 2 O 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.

  13. 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.

  14. 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

  15. Low energy electron point source microscopy: beyond imaging.

    Science.gov (United States)

    Beyer, André; Gölzhäuser, Armin

    2010-09-01

    Low energy electron point source (LEEPS) microscopy has the capability to record in-line holograms at very high magnifications with a fairly simple set-up. After the holograms are numerically reconstructed, structural features with the size of about 2 nm can be resolved. The achievement of an even higher resolution has been predicted. However, a number of obstacles are known to impede the realization of this goal, for example the presence of electric fields around the imaged object, electrostatic charging or radiation induced processes. This topical review gives an overview of the achievements as well as the difficulties in the efforts to shift the resolution limit of LEEPS microscopy towards the atomic level. A special emphasis is laid on the high sensitivity of low energy electrons to electrical fields, which limits the structural determination of the imaged objects. On the other hand, the investigation of the electrical field around objects of known structure is very useful for other tasks and LEEPS microscopy can be extended beyond the task of imaging. The determination of the electrical resistance of individual nanowires can be achieved by a proper analysis of the corresponding LEEPS micrographs. This conductivity imaging may be a very useful application for LEEPS microscopes.

  16. Volume scanning electron microscopy for imaging biological ultrastructure.

    Science.gov (United States)

    Titze, Benjamin; Genoud, Christel

    2016-11-01

    Electron microscopy (EM) has been a key imaging method to investigate biological ultrastructure for over six decades. In recent years, novel volume EM techniques have significantly advanced nanometre-scale imaging of cells and tissues in three dimensions. Previously, this had depended on the slow and error-prone manual tasks of cutting and handling large numbers of sections, and imaging them one-by-one with transmission EM. Now, automated volume imaging methods mostly based on scanning EM (SEM) allow faster and more reliable acquisition of serial images through tissue volumes and achieve higher z-resolution. Various software tools have been developed to manipulate the acquired image stacks and facilitate quantitative analysis. Here, we introduce three volume SEM methods: serial block-face electron microscopy (SBEM), focused ion beam SEM (FIB-SEM) and automated tape-collecting ultramicrotome SEM (ATUM-SEM). We discuss and compare their capabilities, provide an overview of the full volume SEM workflow for obtaining 3D datasets and showcase different applications for biological research. © 2016 Société Française des Microscopies and Société de Biologie Cellulaire de France. Published by John Wiley & Sons Ltd.

  17. 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.

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

    International Nuclear Information System (INIS)

    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

    2014-01-01

    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

  19. Subparticle ultrafast spectrum imaging in 4D electron microscopy.

    Science.gov (United States)

    Yurtsever, Aycan; van der Veen, Renske M; Zewail, Ahmed H

    2012-01-06

    Single-particle imaging of structures has become a powerful methodology in nanoscience and molecular and cell biology. We report the development of subparticle imaging with space, time, and energy resolutions of nanometers, femtoseconds, and millielectron volts, respectively. By using scanning electron probes across optically excited nanoparticles and interfaces, we simultaneously constructed energy-time and space-time maps. Spectrum images were then obtained for the nanoscale dielectric fields, with the energy resolution set by the photon rather than the electron, as demonstrated here with two examples (silver nanoparticles and the metallic copper-vacuum interface). This development thus combines the high spatial resolution of electron microscopy with the high energy resolution of optical techniques and ultrafast temporal response, opening the door to various applications in elemental analysis as well as mapping of interfaces and plasmonics.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. Electron microscopy--new tool for service failure study

    Energy Technology Data Exchange (ETDEWEB)

    Warke, W.R.; McCall, J.L.

    1965-05-01

    Electron microscopy, now well established as a research tool for the study of metal fractures, can be valuable for analyzing service failures. The high magnifications of electron microscopes, ranging from 500 to 200,000 X, coupled with their large vertical resolution, make it possible to distinguish overload failures from fatigue failures from brittle intergranular failures, and so on. Generally speaking, 2 basic techniques are used to replicate fractured surfaces. They the direct carbon method and the 2-stage plastic carbon technique. Each has its limitations and specific areas of application. Direct carbon eliminates an intermediate step; it thus gives a higher fidelity replica and allows extraction of inclusions and precipitates, but destroys the sample. The plastic carbon replica is nondestructive, but less faithful in reproducing the finest features of the surface. For this reason, the direct method is used primarily for fundamental research, while the plastic carbon technique is used when specimen availability is a problem or service failures are to be analyzed. The applicability of electron microscopy to service failure analyses is illustrated by 3 examples.

  5. 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.

  6. 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.

  7. 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

  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. The thin layer technique and its application to electron microscopy

    International Nuclear Information System (INIS)

    Ranc, G.

    1957-10-01

    This work deals with the technique of thin layers obtained by evaporation under vacuum, in the thickness range extending from a few monoatomic layers to several hundred angstroms. The great theoretical and practical interest of these layers has, it is well known, given rise to many investigations from Faraday onwards. Within the necessarily restricted limits of this study, we shall approach the problem more particularly from the point of view of: - their production; - their use in electron microscopy. A critical appraisal is made, in the light of present-day knowledge, based on our personal experience and on an extensive bibliography which we have collected on the subject. (author) [fr

  10. Progress and applications of in situ transmission electron microscopy

    International Nuclear Information System (INIS)

    Wang Rongming; Liu Jialong; Song Yuanjun

    2015-01-01

    Recent progress in the application of in situ transmission electron microscopy (TEM) is briefly reviewed. It is emphasized that the development of advanced in situ TEM techniques makes it possible to investigate the evolution of materials under heat, strain, magnetic field, electric field or chemical reaction environments on the atomic scale. The mechanism of the microstructure evolution under various conditions and the relationship between the atomic structures and their properties can be obtained, which is beneficial for the design of new materials with tailored properties. The clarification of the structure-property relationship will help to develop new materials and solve related basic problems in the field of condensed matter physics. (authors)

  11. 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

    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...... analysis performing gold sputter coating under vacuum and were examined using 15kV at 500x and 2000x magnification. Results: Morphological alterations on the enamel surface were similarly detected after bleaching with either 35% carbamide peroxide or 35% hydrogen peroxide. Surface porosities were...

  12. Analysis of archaeological materials through Scanning electron microscopy

    International Nuclear Information System (INIS)

    Camacho, A.; Tenorio C, D.; Elizalde, S.; Mandujano, C.; Cassiano, G.

    2005-01-01

    With the purpose to know the uses and the chemical composition of some cultural objects in the pre hispanic epoch this work presents several types of analysis for identifying them by means of the Scanning electron microscopy and its techniques as the Functional analysis of artifacts based on the 'tracks of use' analysis, also the X-ray spectroscopy and the X-ray dispersive energy (EDS) are mentioned, all of them allowing a major approach to the pre hispanic culture in Mexico. (Author)

  13. Examination of living fungal spores by scanning electron microscopy

    International Nuclear Information System (INIS)

    Read, N.D.; Lord, K.M.

    1991-01-01

    Ascospores of Sordaria macrospora germinated and produced hyphae exhibiting normal growth and differentiation after examination by scanning electron microscopy and following numerous, different preparative protocols. Seventy-nine to ninety-nine percent of the ascospores retained normal viability after being observed in the fully frozen-hydrated, partially freeze-dried, and vacuum-dried states at accelerating voltages of 5 and 40 keV. Hyphae did not survive these treatments. From these observations it is concluded that ascospores of S. macrospora can remain in a state of suspended animation while being observed in the scanning electron microscope. The ascospores also survived, but with reduced viability: 6 h in glutaraldehyde and formaldehyde, 6 h in OsO4, or 2 h in glutaraldehyde and formaldehyde followed by 2 h in OsO 4 . However, the ascospores did not germinate after dehydration in ethanol. (author)

  14. 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

  15. 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.

  16. Software electron counting for low-dose scanning transmission electron microscopy.

    Science.gov (United States)

    Mittelberger, Andreas; Kramberger, Christian; Meyer, Jannik C

    2018-02-17

    The performance of the detector is of key importance for low-dose imaging in transmission electron microscopy, and counting every single electron can be considered as the ultimate goal. In scanning transmission electron microscopy, low-dose imaging can be realized by very fast scanning, however, this also introduces artifacts and a loss of resolution in the scan direction. We have developed a software approach to correct for artifacts introduced by fast scans, making use of a scintillator and photomultiplier response that extends over several pixels. The parameters for this correction can be directly extracted from the raw image. Finally, the images can be converted into electron counts. This approach enables low-dose imaging in the scanning transmission electron microscope via high scan speeds while retaining the image quality of artifact-free slower scans. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

  17. 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).

  18. 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.

  19. Transmission electron microscopy and the molecular structure of icosahedral viruses.

    Science.gov (United States)

    San Martín, Carmen

    2015-09-01

    The field of structural virology developed in parallel with methodological advances in X-ray crystallography and cryo-electron microscopy. At the end of the 1970s, crystallography yielded the first high resolution structure of an icosahedral virus, the T=3 tomato bushy stunt virus at 2.9Å. It took longer to reach near-atomic resolution in three-dimensional virus maps derived from electron microscopy data, but this was finally achieved, with the solution of complex icosahedral capsids such as the T=25 human adenovirus at ∼3.5Å. Both techniques now work hand-in-hand to determine those aspects of virus assembly and biology that remain unclear. This review examines the trajectory followed by EM imaging techniques in showing the molecular structure of icosahedral viruses, from the first two-dimensional negative staining images of capsids to the latest sophisticated techniques that provide high resolution three-dimensional data, or snapshots of the conformational changes necessary to complete the infectious cycle. Copyright © 2015 Elsevier Inc. All rights reserved.

  20. 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.

  1. 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...

  2. Collaborative Computational Project for Electron cryo-Microscopy

    International Nuclear Information System (INIS)

    Wood, Chris; Burnley, Tom; Patwardhan, Ardan; Scheres, Sjors; Topf, Maya; Roseman, Alan; Winn, Martyn

    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

  3. 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.

  4. 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.)

  5. 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.

  6. Sequential Immunofluorescent Light Microscopy and Electron Microscopy of Recombination Nodules During Meiotic Prophase I.

    Science.gov (United States)

    Anderson, Lorinda K

    2017-01-01

    Immunolocalization using either fluorescence for light microscopy (LM) or gold particles for electron microscopy (EM) has become a common tool to pinpoint proteins involved in recombination during meiotic prophase. Each method has its advantages and disadvantages. For example, LM immunofluorescence is comparatively easier and higher throughput compared to immunogold EM localization. In addition, immunofluorescence has the advantages that a faint signal can often be enhanced by longer exposure times and colocalization using two (or more) probes with different absorbance and emission spectra is straightforward. However, immunofluorescence is not useful if the object of interest does not label with an antibody probe and is below the resolution of the LM. In comparison, immunogold EM localization is higher resolution than immunofluorescent LM localization, and individual nuclear structures, such as recombination nodules, can be identified by EM regardless of whether they are labeled or not. However, immunogold localization has other disadvantages including comparatively low signal-to-noise ratios, more difficult colocalization using gold particles of different sizes, and the inability to evaluate labeling efficiency before examining the sample using EM (a more expensive and time-consuming technique than LM). Here we describe a method that takes advantage of the good points of both immunofluorescent LM and EM to analyze two classes of late recombination nodules (RNs), only one of which labels with antibodies to MLH1 protein, a marker of crossovers. The method can be used readily with other antibodies to analyze early recombination nodules or other prophase I structures.

  7. Micro-CT scan, electron microscopy and optical microscopy study of insertional traumas of cochlear implants.

    Science.gov (United States)

    Le Breton, Alexia; Jegoux, Franck; Pilet, Paul; Godey, Benoit

    2015-09-01

    Knowledge of cochlear trauma resulting from the implantation of electrodes is important for the development of atraumatic surgical techniques. The purpose of this study was to demonstrate the advantages of micro-CT scanning, back-scattered electron microscopy (BSEM) and optical microscopy (OM) in understanding the mechanisms of cochlear trauma due to cochlear implantation. Our study involved six petrous bones removed from fresh human cadavers: one control specimen plus five other specimens that were surgically implanted with Neurelec Digisonic SP EVO electrode arrays. All six specimens underwent glycol methyl methacrylate embedding, were examined via micro-CT scan and were then sectioned for histological analysis of undecalcified samples via BSEM and OM. The 2D micro-CT scan reconstructions did not display cochlear microtrauma due to a limited resolution and the loss of information caused by the metallic artifacts of the intracochlear electrodes. The 3D reconstructions displayed the quality of the electrode array positioning in the cochlea and enabled determining the axes on which to section the specimens for histological examination. BSEM afforded a clear view of the damage to the osseous structures of the cochlea, but did not display the soft tissue injuries. OM enabled viewing and grading the histological lesions resulting from insertion. In our opinion, the combination of 3D micro-CT scan reconstructions and histological analysis using OM appears to be the best method to analyze this type of trauma.

  8. 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.

  9. Transmission electron microscopy characterisation of 0-D nanomaterials

    Science.gov (United States)

    Turner, Stuart Matthew

    When materials are scaled down to the nanometre level, a change in physical behaviour is frequently observed. In so-called 0-D nanomaterials (nanoparticles), these unique nanoscale properties are most abundant and are usually linked to either a change in (electronic) structure of the material or to the dominating influence of the particle surface at the nanometre scale. In this doctoral work the nanoscale properties of several nanoparticle systems have been studied using advanced transmission electron microscopy (TEM). Every material that was studied required for its solution a unique approach and a host of transmission electron microscopy techniques. The title of this doctoral work can be freely translated as "retrieving quantitatively the maximal and most accurate chemical, structural and morphological information from nanoparticles by advanced transmission electron microscopy, to uncover and explain their unique properties". Chapter 1 gives a brief general introduction to the world of nanomaterials and nanotechnology in general and more specifically to 0-D nanomaterials (nanoparticles). The unique properties and potential applications of these materials are described. The production of 0-D nanomaterials is not covered in this chapter, as this is an extremely broad field to cover in only a few pages. Instead, the production method for each of the materials is left to the detailed chapters that follow. In Chapter 2 the main transmission electron microscopy techniques used to characterise the materials in the further chapters are described together with the microscopes used to perform these techniques and their parameters of operation. Again, the sample-specific setups are listed in the detailed chapters that follow. Chapter 3 covers all work carried out on luminescent detonation nanodiamond powder for drug delivery and bio-medical imaging applications. Specific attention is paid to the morphology, surface chemistry and nitrogen incorporation of detonation

  10. 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...

  11. 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.

  12. Robust image alignment for cryogenic transmission electron microscopy.

    Science.gov (United States)

    McLeod, Robert A; Kowal, Julia; Ringler, Philippe; Stahlberg, Henning

    2017-03-01

    Cryo-electron microscopy recently experienced great improvements in structure resolution due to direct electron detectors with improved contrast and fast read-out leading to single electron counting. High frames rates enabled dose fractionation, where a long exposure is broken into a movie, permitting specimen drift to be registered and corrected. The typical approach for image registration, with high shot noise and low contrast, is multi-reference (MR) cross-correlation. Here we present the software package Zorro, which provides robust drift correction for dose fractionation by use of an intensity-normalized cross-correlation and logistic noise model to weight each cross-correlation in the MR model and filter each cross-correlation optimally. Frames are reliably registered by Zorro with low dose and defocus. Methods to evaluate performance are presented, by use of independently-evaluated even- and odd-frame stacks by trajectory comparison and Fourier ring correlation. Alignment of tiled sub-frames is also introduced, and demonstrated on an example dataset. Zorro source code is available at github.com/CINA/zorro. Copyright © 2016 Elsevier Inc. All rights reserved.

  13. 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.

  14. 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.

  15. Light and transmission electronic microscopy evaluation of lyophilized corneas.

    Science.gov (United States)

    Farias, Roberta J M; Sousa, Luciene B; Lima Filho, Acácio A S; Lourenço, Andréa C S; Tanakai, Márcia H; Freymuller, Edna

    2008-08-01

    Cornea storage for longer periods is still a challenge for corneal surgeons. The purpose of this study was to find a method to lyophilize corneas for anterior lamellar transplant and to evaluate them by light and transmission electronic microscopy. Corneal flaps were created by using a microkeratome. Corneas were lyophilized with a cryoprotectant (2.3 mol sacarousis for 40 minutes) and without a cryoprotectant in a lyophilization machine (Modulyon D). The corneas were rehydrated with distilled water, balanced saline solution (BSS), and phosphate-buffered saline, after which they were evaluated by microscopy. A cornea that did not undergo lyophilization served as a control. Lyophilization without a cryoprotectant did not preserve the corneal structure. This finding was also observed when lyophilizing and rehydrating the corneas with distilled water or phosphate-buffered saline. We found that lyophilizing corneas and rehydrating them with 11 mL of BSS for 30 minutes preserved the general corneal structure, the parallelism of the collagen fibers, the Bowman layer, and the epithelial basement membrane for 15 and 30 days and for as long as 1 year or more. Lyophilization with sacarousis and rehydration with BSS may be a good method for anterior lamellar transplantation.

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

    Science.gov (United States)

    Koeck, Philip J B

    2016-02-01

    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. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. High-resolution electron microscopy and its applications.

    Science.gov (United States)

    Li, F H

    1987-12-01

    A review of research on high-resolution electron microscopy (HREM) carried out at the Institute of Physics, the Chinese Academy of Sciences, is presented. Apart from the direct observation of crystal and quasicrystal defects for some alloys, oxides, minerals, etc., and the structure determination for some minute crystals, an approximate image-contrast theory named pseudo-weak-phase object approximation (PWPOA), which shows the image contrast change with crystal thickness, is described. Within the framework of PWPOA, the image contrast of lithium ions in the crystal of R-Li2Ti3O7 has been observed. The usefulness of diffraction analysis techniques such as the direct method and Patterson method in HREM is discussed. Image deconvolution and resolution enhancement for weak-phase objects by use of the direct method are illustrated. In addition, preliminary results of image restoration for thick crystals are given.

  18. Watershed Merge Tree Classification for Electron Microscopy Image Segmentation.

    Science.gov (United States)

    Liu, Ting; Jurrus, Elizabeth; Seyedhosseini, Mojtaba; Ellisman, Mark; Tasdizen, Tolga

    2012-11-01

    Automated segmentation of electron microscopy (EM) images is a challenging problem. In this paper, we present a novel method that utilizes a hierarchical structure and boundary classification for 2D neuron segmentation. With a membrane detection probability map, a watershed merge tree is built for the representation of hierarchical region merging from the watershed algorithm. A boundary classifier is learned with non-local image features to predict each potential merge in the tree, upon which merge decisions are made with consistency constraints to acquire the final segmentation. Independent of classifiers and decision strategies, our approach proposes a general framework for efficient hierarchical segmentation with statistical learning. We demonstrate that our method leads to a substantial improvement in segmentation accuracy.

  19. 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.

  20. 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.

  1. Transmission electron microscopy analysis of hydroxyapatite nanocrystals from cattle bones

    Energy Technology Data Exchange (ETDEWEB)

    Patel, Sangeeta, E-mail: spt658@aucklanduni.ac.nz [Department of Chemical and Materials Engineering, The University of Auckland, 20 Symonds Street, Auckland 1010 (New Zealand); Wei, Shanghai [Department of Chemical and Materials Engineering, The University of Auckland, 20 Symonds Street, Auckland 1010 (New Zealand); Han, Jie [Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, 205 North Mathews Avenue, Urbana, IL (United States); Gao, Wei [Department of Chemical and Materials Engineering, The University of Auckland, 20 Symonds Street, Auckland 1010 (New Zealand)

    2015-11-15

    In this present study, hydroxyapatite which was obtained from cattle bones has been heat treated at temperature 400 °C and 600 °C. The microstructure after the treatment has been studied in detail using Transmission electron microscopy (TEM) and X-ray diffraction techniques. The TEM results indicate that natural bone consists of collagen and hydroxyapatite nano-crystals which are needle shaped. The heat treatment influences the crystallinity and growth of these hydroxyapatite nano-crystals known as ‘crystal maturation’ or ‘crystal ageing’. - Highlights: • Hydroxyapatite is obtained from cattle bones. • Material has been characterised using XRD and TEM. • Crystal growth and orientation has been studied in detail.

  2. Electron microscopy and plastic deformation of industrial austenitic stainless steels

    International Nuclear Information System (INIS)

    Thomas, Barry

    1976-01-01

    The different mechanisms of plastic deformation observed in austenitic stainless steels are described and the role of transmission electron microscopy in the elucidation of the mechanisms is presented. At temperatures below 0,5Tm, different variants of dislocation glide are competitive: slip of perfect and partial dislocations, mechanical twinning and strain-induced phase transformations. The predominance of one or other of these mechanisms can be rationalized in terms of the temperature and composition dependence of the stacking fault energy and the thermodynamic stability of the austenite. At temperatures above 0,5Tm dislocation climb and diffusion of point defects become increasingly important and at these temperatures recovery, recrystallization and precipitation can also occur during deformation [fr

  3. Analytical Chemistry of Surfaces: Part II. Electron Spectroscopy.

    Science.gov (United States)

    Hercules, David M.; Hercules, Shirley H.

    1984-01-01

    Discusses two surface techniques: X-ray photoelectron spectroscopy (ESCA) and Auger electron spectroscopy (AES). Focuses on fundamental aspects of each technique, important features of instrumentation, and some examples of how ESCA and AES have been applied to analytical surface problems. (JN)

  4. Scanning electron microscopy of Strongylus spp. in zebra.

    Science.gov (United States)

    Els, H J; Malan, F S; Scialdo-Krecek, R C

    1983-12-01

    The external ultrastructure of the anterior and posterior extremities of the nematodes, Strongylus asini , Strongylus vulgaris, Strongylus equinus and Strongylus edentatus, was studied with scanning electron microscopy (SEM). Fresh specimens of S. asini were collected from the caecum, ventral colon and vena portae of Equus burchelli and Equus zebra hartmannae ; S. vulgaris from the caecum, colon and arteria ileocolica of E. burchelli ; S. equinus from the ventral colon of E. z. hartmannae and S. edentatus from the caecum and ventral colon of both zebras , during surveys of parasites in zebras in the Etosha Game Reserve, South West Africa/Namibia, and the Kruger National Park, Republic of South Africa. The worms were cleaned, fixed and mounted by standard methods and photographed in a JEOL JSM - 35C scanning electron microscope (SEM) operating at 12kV . The SEM showed the following differences: the tips of the external leaf-crowns varied and were fine and delicate in S. asini , coarse and broad in S. vulgaris and, in S. equinus and S. edentatus, closely adherent, separating into single elements for half their length. The excretory pores showed only slight variation, and the morphology of the copulatory bursae did not differ from those seen with light microscopy. The genital cones differed markedly: S. asini had a ventral triangular projection and laterally 2 finger-like projections: in S. vulgaris there were numerous bosses on the lateral and ventral aspects of the cone; in S. equinus 2 finger-like processes projected laterocaudally ; and in S. edentatus 2 pairs of papilla-like processes projected laterally on the ventral aspects, and a pair of rounded projections and a pair of hair-like structures adorned the dorsal aspects.(ABSTRACT TRUNCATED AT 250 WORDS)

  5. Electron microscopy study of the iron meteorite Santa Catharina

    Science.gov (United States)

    Zhang, J.; Williams, D. B.; Goldstein, J. I.; Clarke, R. S., Jr.

    1990-01-01

    A characterization of the microstructural features of Santa Catharina (SC) from the millimeter to submicron scale is presented. The same specimen was examined using an optical microscope, a scanning electron microscope, an electron probe microanalyzer, and an analytical electron microscope. Findings include the fact that SC metal nodules may have different bulk Ni values, leading to different microstructures upon cooling; that SC USNM 6293 is the less corroded sample, as tetrataenite exists as less than 10 nm ordered domains throughout the entire fcc matrix (it is noted that this structure is the same as that of the Twin City meteorite and identical to clear taenite II in the retained taenite regions of the octahedrites); that SC USNM 3043 has a more complicated microstructure due to corrosion; and that the low Ni phase of the cloudy zone was selectively corroded in some areas and formed the dark regions, indicating that the SC meteorite corrosion process was electrochemical in nature and may involve Cl-containing akaganeite.

  6. Analytical electron microscope study of the omega phase transformation in a zirconium--niobium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Zaluzec, N.J.

    1979-06-01

    An in-situ study of the as-quenched omega phase transformation in Zr--15% Nb was conducted between the temperatures of 77 and 300/sup 0/K using analytical electron microscopy. The domain size of the omega regions observed in this investigation was on the order of 30 A, consistent with previous observations in this system. No alignment of omega domains along <222> directions of the bcc lattice was observed and in-situ thermal cycling experiments failed to produce a long period structure of alternating ..beta.. and ..omega.. phase regions as predicted by one theory of this transformation. Several techniques of microstructural analysis were developed, refined, and standardized. Grouped under the general classification of Analytical Electron Microscopy (AEM) they provide the experimentalist with a unique tool for the microcharacterization of solids, allowing semiquantitative to quantitative analysis of the morphology, crystallography, elemental composition, and electronic structure of regions as small as 20 A in diameter. These techniques have complications, and it was necessary to study the AEM system used in this work so that instrumental artifacts which invalidate the information produced in the microscope environment might be eliminated. Once these factors had been corrected, it was possible to obtain a wealth of information about the microvolume of material under investigation. The microanalytical techniques employed during this research include: energy dispersive x-ray spectroscopy (EDS) using both conventional and scanning transmission electron microscopy (CTEM, STEM), transmission scanning electron diffraction (TSED), the stationary diffraction pattern technique, and electron energy loss spectroscopy (ELS) using a dedicated scanning transmission electron microscope (DSTEM).

  7. Analytical electron microscope study of the omega phase transformation in a zirconium--niobium alloy

    International Nuclear Information System (INIS)

    Zaluzec, N.J.

    1979-06-01

    An in-situ study of the as-quenched omega phase transformation in Zr--15% Nb was conducted between the temperatures of 77 and 300 0 K using analytical electron microscopy. The domain size of the omega regions observed in this investigation was on the order of 30 A, consistent with previous observations in this system. No alignment of omega domains along directions of the bcc lattice was observed and in-situ thermal cycling experiments failed to produce a long period structure of alternating β and ω phase regions as predicted by one theory of this transformation. Several techniques of microstructural analysis were developed, refined, and standardized. Grouped under the general classification of Analytical Electron Microscopy (AEM) they provide the experimentalist with a unique tool for the microcharacterization of solids, allowing semiquantitative to quantitative analysis of the morphology, crystallography, elemental composition, and electronic structure of regions as small as 20 A in diameter. These techniques have complications, and it was necessary to study the AEM system used in this work so that instrumental artifacts which invalidate the information produced in the microscope environment might be eliminated. Once these factors had been corrected, it was possible to obtain a wealth of information about the microvolume of material under investigation. The microanalytical techniques employed during this research include: energy dispersive x-ray spectroscopy (EDS) using both conventional and scanning transmission electron microscopy (CTEM, STEM), transmission scanning electron diffraction (TSED), the stationary diffraction pattern technique, and electron energy loss spectroscopy (ELS) using a dedicated scanning transmission electron microscope

  8. High quality ultrafast transmission electron microscopy using resonant microwave cavities.

    Science.gov (United States)

    Verhoeven, W; van Rens, J F M; Kieft, E R; Mutsaers, P H A; Luiten, O J

    2018-03-10

    Ultrashort, low-emittance electron pulses can be created at a high repetition rate by using a TM 110 deflection cavity to sweep a continuous beam across an aperture. These pulses can be used for time-resolved electron microscopy with atomic spatial and temporal resolution at relatively large average currents. In order to demonstrate this, a cavity has been inserted in a transmission electron microscope, and picosecond pulses have been created. No significant increase of either emittance or energy spread has been measured for these pulses. At a peak current of 814 ± 2 pA, the root-mean-square transverse normalized emittance of the electron pulses is ɛ n,x =(2.7±0.1)·10 -12  m rad in the direction parallel to the streak of the cavity, and ɛ n,y =(2.5±0.1)·10 -12  m rad in the perpendicular direction for pulses with a pulse length of 1.1-1.3 ps. Under the same conditions, the emittance of the continuous beam is ɛ n,x =ɛ n,y =(2.5±0.1)·10 -12  m rad. Furthermore, for both the pulsed and the continuous beam a full width at half maximum energy spread of 0.95 ± 0.05 eV has been measured. Copyright © 2018 Elsevier B.V. All rights reserved.

  9. 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

  10. Scanning electron microscopy and electron probe X-ray microanalysis (SEM-EPMA) of pink teeth

    International Nuclear Information System (INIS)

    Ikeda, N.; Watanabe, G.; Harada, A.; Suzuki, T.

    1988-01-01

    Samples of postmortem pink teeth were investigated by scanning electron microscopy and electron probe X-ray microanalysis. Fracture surfaces of the dentin in pink teeth were noticeably rough and revealed many more smaller dentinal tubules than those of the control white teeth. Electron probe X-ray microanalysis showed that the pink teeth contained iron which seemed to be derived from blood hemoglobin. The present study confirms that under the same circumstance red coloration of teeth may occur more easily in the teeth in which the dentin is less compact and contains more dentinal tubules

  11. Soft x-ray microscopy - a powerful analytical tool to image magnetism down to fundamental length and times scales

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, Peter

    2008-08-01

    The magnetic properties of low dimensional solid state matter is of the utmost interest both scientifically as well as technologically. In addition to the charge of the electron which is the base for current electronics, by taking into account the spin degree of freedom in future spintronics applications open a new avenue. Progress towards a better physical understanding of the mechanism and principles involved as well as potential applications of nanomagnetic devices can only be achieved with advanced analytical tools. Soft X-ray microscopy providing a spatial resolution towards 10nm, a time resolution currently in the sub-ns regime and inherent elemental sensitivity is a very promising technique for that. This article reviews the recent achievements of magnetic soft X-ray microscopy by selected examples of spin torque phenomena, stochastical behavior on the nanoscale and spin dynamics in magnetic nanopatterns. The future potential with regard to addressing fundamental magnetic length and time scales, e.g. imaging fsec spin dynamics at upcoming X-ray sources is pointed out.

  12. 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.

  13. Liquid-Cell Electron Microscopy of Adsorbed Polymers.

    Science.gov (United States)

    Nagamanasa, Kandula Hima; Wang, Huan; Granick, Steve

    2017-11-01

    Individual macromolecules of polystyrene sulfonate and poly(ethylene oxide) are visualized with nanometer resolution using transmission electron microscopy (TEM) imaging of aqueous solutions with and without added salt, trapped in liquid pockets between creased graphene sheets. Successful imaging with 0.3 s per frame is enabled by the sluggish mobility of the adsorbed molecules. This study finds, validating others, that an advantage of this graphene liquid-cell approach is apparently to retard sample degradation from incident electrons, in addition to minimizing background scattering because graphene windows are atomically thin. Its new application here to polymers devoid of metal-ion labeling allows the projected sizes and conformational fluctuations of adsorbed molecules and adsorption-desorption events to be analyzed. Confirming the identification of the observed objects, this study reports statistical analysis of datasets of hundreds of images for times up to 100 s, with variation of the chemical makeup of the polymer, the molecular weight of the polymer, and the salt concentration. This observation of discrete polymer molecules in solution environment may be useful generally, as the findings are obtained using an ordinary TEM microscope, whose kind is available to many researchers routinely. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Analytical X-ray microscopy using laboratory sources: Method and results

    International Nuclear Information System (INIS)

    Wulveryck, J.M.; Odof, S.; Patat, J.M.; Mouze, D.

    2000-01-01

    The implementation of X-ray imaging techniques (X-Ray Projection Microscopy or X-Ray Microtomography) for analytical purpose with laboratory equipment is not easily obtainable, due to the use of polychromatic X-ray sources. To overcome this drawback, we propose here a mathematical technique based upon the calculation of the X-ray emission spectra and the knowledge of the spectral response of the camera. For example, we show that the composition of a ternary sample can be deduced from two images measurements recorded from two primary radiation. The accuracy of the method is discussed

  15. Deep-depletion physics-based analytical model for scanning capacitance microscopy carrier profile extraction

    International Nuclear Information System (INIS)

    Wong, K. M.; Chim, W. K.

    2007-01-01

    An approach for fast and accurate carrier profiling using deep-depletion analytical modeling of scanning capacitance microscopy (SCM) measurements is shown for an ultrashallow p-n junction with a junction depth of less than 30 nm and a profile steepness of about 3 nm per decade change in carrier concentration. In addition, the analytical model is also used to extract the SCM dopant profiles of three other p-n junction samples with different junction depths and profile steepnesses. The deep-depletion effect arises from rapid changes in the bias applied between the sample and probe tip during SCM measurements. The extracted carrier profile from the model agrees reasonably well with the more accurate carrier profile from inverse modeling and the dopant profile from secondary ion mass spectroscopy measurements

  16. 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.

  17. New developments in electron microscopy for serial image acquisition of neuronal profiles.

    Science.gov (United States)

    Kubota, Yoshiyuki

    2015-02-01

    Recent developments in electron microscopy largely automate the continuous acquisition of serial electron micrographs (EMGs), previously achieved by laborious manual serial ultrathin sectioning using an ultramicrotome and ultrastructural image capture process with transmission electron microscopy. The new systems cut thin sections and capture serial EMGs automatically, allowing for acquisition of large data sets in a reasonably short time. The new methods are focused ion beam/scanning electron microscopy, ultramicrotome/serial block-face scanning electron microscopy, automated tape-collection ultramicrotome/scanning electron microscopy and transmission electron microscope camera array. In this review, their positive and negative aspects are discussed. © 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.

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

    International Nuclear Information System (INIS)

    Schorb, Martin; Briggs, John A.G.

    2014-01-01

    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. - 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

  19. 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.

  20. Overview of electron crystallography of membrane proteins: crystallization and screening strategies using negative stain electron microscopy.

    Science.gov (United States)

    Nannenga, Brent L; Iadanza, Matthew G; Vollmar, Breanna S; Gonen, Tamir

    2013-01-01

    Electron cryomicroscopy, or cryoEM, is an emerging technique for studying the three-dimensional structures of proteins and large macromolecular machines. Electron crystallography is a branch of cryoEM in which structures of proteins can be studied at resolutions that rival those achieved by X-ray crystallography. Electron crystallography employs two-dimensional crystals of a membrane protein embedded within a lipid bilayer. The key to a successful electron crystallographic experiment is the crystallization, or reconstitution, of the protein of interest. This unit describes ways in which protein can be expressed, purified, and reconstituted into well-ordered two-dimensional crystals. A protocol is also provided for negative stain electron microscopy as a tool for screening crystallization trials. When large and well-ordered crystals are obtained, the structures of both protein and its surrounding membrane can be determined to atomic resolution.

  1. 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

  2. Capturing enveloped viruses on affinity grids for downstream cryo-electron microscopy applications

    Science.gov (United States)

    Electron microscopy cryo-electron microscopy and cryo-electron tomography are essential techniques used for characterizing basic virus morphology and determining the three-dimensional structure of viruses. Enveloped viruses, which contain an outer lipoprotein coat, constitute the largest group of pa...

  3. Correlative Fluorescence and Electron Microscopy in 3D-Scanning Electron Microscope Perspective.

    Science.gov (United States)

    Franks, Jonathan; Wallace, Callen T; Shibata, Masateru; Suga, Mitsuo; Erdman, Natasha; Stolz, Donna B; Watkins, Simon C

    2017-04-03

    The ability to correlate fluorescence microscopy (FM) and electron microscopy (EM) data obtained on biological (cell and tissue) specimens is essential to bridge the resolution gap between the data obtained by these different imaging techniques. In the past such correlations were limited to either EM navigation in two dimensions to the locations previously highlighted by fluorescence markers, or subsequent high-resolution acquisition of tomographic information using a TEM. We present a novel approach whereby a sample previously investigated by FM is embedded and subjected to sequential mechanical polishing and backscatter imaging by scanning electron microscope. The resulting three dimensional EM tomogram of the sample can be directly correlated to the FM data. © 2017 by John Wiley & Sons, Inc. Copyright © 2017 John Wiley & Sons, Inc.

  4. 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.

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

    Science.gov (United States)

    Lunov, O.; Churpita, O.; Zablotskii, V.; Deyneka, I. G.; Meshkovskii, I. K.; Jäger, A.; Syková, E.; Kubinová, Š.; Dejneka, A.

    2015-02-01

    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.

  6. Low Voltage Transmission Electron Microscopy in Cell Biology.

    Science.gov (United States)

    Bendayan, Moise; Paransky, Eugene

    2015-07-01

    Low voltage transmission electron microscopy (LVTEM) was employed to examine biological tissues with accelerating voltages as low as 5kV. Tissue preparation was modified to take advantage of the low-voltage techniques. Treatments with heavy metals, such as post-fixation with osmium tetroxide, on block and counterstaining were omitted. Sections (40nm) were thinner than usual and generated highly contrasted images. General appearance of the cells remains similar to that of conventional TEM. New features were however revealed. The matrix of the pancreatic granules displays heterogeneity with partitions that may correspond to the inner-segregation of their secretory proteins. Mitochondria revealed the presence of the ATP synthase granules along their cristea. The nuclear dense chromatin displayed a honeycomb organization while distinct beads, nucleosomes, aligned along thin threads were seen in the dispersed chromatin. Nuclear pore protein complexes revealed their globular nature. The intercalated disks in cardiac muscle displayed their fine structural organization. These features correlate well with data described or predicted by cell and molecular biology. These new aspects are not revealed when thicker and conventionally osmicated tissue sections were examined by LVTEM, indicating that major masking effects are associated with standard TEM techniques. Immunogold was adapted to LVTEM further enhancing its potential in cell biology. Copyright © 2015 Elsevier GmbH. All rights reserved.

  7. 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.

  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. An overview on bioaerosols viewed by scanning electron microscopy

    International Nuclear Information System (INIS)

    Wittmaack, K.; Wehnes, H.; Heinzmann, U.; Agerer, R.

    2005-01-01

    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 μm. The collected particles, sampled for short periods (∼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 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

  10. Individual Particle Analysis of Ambient PM 2.5 Using Advanced Electron Microscopy Techniques

    Energy Technology Data Exchange (ETDEWEB)

    Gerald J. Keeler; Masako Morishita

    2006-12-31

    The overall goal of this project was to demonstrate a combination of advanced electron microscopy techniques that can be effectively used to identify and characterize individual particles and their sources. Specific techniques to be used include high-angle annular dark field scanning transmission electron microscopy (HAADF-STEM), STEM energy dispersive X-ray spectrometry (EDX), and energy-filtered TEM (EFTEM). A series of ambient PM{sub 2.5} samples were collected in communities in southwestern Detroit, MI (close to multiple combustion sources) and Steubenville, OH (close to several coal fired utility boilers). High-resolution TEM (HRTEM) -imaging showed a series of nano-metal particles including transition metals and elemental composition of individual particles in detail. Submicron and nano-particles with Al, Fe, Ti, Ca, U, V, Cr, Si, Ba, Mn, Ni, K and S were observed and characterized from the samples. Among the identified nano-particles, combinations of Al, Fe, Si, Ca and Ti nano-particles embedded in carbonaceous particles were observed most frequently. These particles showed very similar characteristics of ultrafine coal fly ash particles that were previously reported. By utilizing HAADF-STEM, STEM-EDX, and EF-TEM, this investigation was able to gain information on the size, morphology, structure, and elemental composition of individual nano-particles collected in Detroit and Steubenville. The results showed that the contributions of local combustion sources - including coal fired utilities - to ultrafine particle levels were significant. Although this combination of advanced electron microscopy techniques by itself can not identify source categories, these techniques can be utilized as complementary analytical tools that are capable of providing detailed information on individual particles.

  11. 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.

  12. 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.

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

    Science.gov (United States)

    Zhang, Daliang; Zhu, Yihan; Liu, Lingmei; Ying, Xiangrong; Hsiung, Chia-En; Sougrat, Rachid; Li, Kun; Han, Yu

    2018-02-01

    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.

  14. Physical methods for studying minerals and solid materials: X-ray, electron and neutron diffraction; scanning and transmission electron microscopy; X-ray, electron and ion spectrometry

    International Nuclear Information System (INIS)

    Eberhart, J.-P.

    1976-01-01

    The following topics are discussed: theoretical aspects of radiation-matter interactions; production and measurement of radiations (X rays, electrons, neutrons); applications of radiation interactions to the study of crystalline materials. The following techniques are presented: X-ray and neutron diffraction, electron microscopy, electron diffraction, X-ray fluorescence analysis, electron probe microanalysis, surface analysis by electron emission spectrometry (ESCA and Auger electrons), scanning electron microscopy, secondary ion emission analysis [fr

  15. Electron Tomography: A Three-Dimensional Analytic Tool for Hard and Soft Materials Research.

    Science.gov (United States)

    Ercius, Peter; Alaidi, Osama; Rames, Matthew J; Ren, Gang

    2015-10-14

    Three-dimensional (3D) structural analysis is essential to understand the relationship between the structure and function of an object. Many analytical techniques, such as X-ray diffraction, neutron spectroscopy, and electron microscopy imaging, are used to provide structural information. Transmission electron microscopy (TEM), one of the most popular analytic tools, has been widely used for structural analysis in both physical and biological sciences for many decades, in which 3D objects are projected into two-dimensional (2D) images. In many cases, 2D-projection images are insufficient to understand the relationship between the 3D structure and the function of nanoscale objects. Electron tomography (ET) is a technique that retrieves 3D structural information from a tilt series of 2D projections, and is gradually becoming a mature technology with sub-nanometer resolution. Distinct methods to overcome sample-based limitations have been separately developed in both physical and biological science, although they share some basic concepts of ET. This review discusses the common basis for 3D characterization, and specifies difficulties and solutions regarding both hard and soft materials research. It is hoped that novel solutions based on current state-of-the-art techniques for advanced applications in hybrid matter systems can be motivated. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. EDITORIAL: Electron Microscopy and Analysis Group Conference 2011 (EMAG 2011)

    Science.gov (United States)

    Moebus, Guenter; Walther, Thomas; Brydson, Rik; Ozkaya, Dogan; MacLaren, Ian; Donnelly, Steve; Nellist, Pete; Li, Ziyou; Baker, Richard; Chiu, YuLung

    2012-07-01

    The biennial EMAG conference has established a strong reputation as a key event for the national and international electron microscopy community. In 2011 the meeting was held at The University of Birmingham, and I must first take this opportunity of thanking Birmingham for hosting the conference and for the excellent support we received from the local organisers. As a committee, we are delighted to see that enthusiasm for the EMAG conference series continues to be strong. We received more than 160 submitted abstracts, and 157 delegates attended the meeting. The scientific programme organiser, Ian MacLaren, put together an exciting programme. Plenary lectures were presented by Professor Knut Urban, Dr Frances Ross and Dr Richard Henderson. There were a further 10 invited speakers, from the UK, Continental Europe, Australia, the USA and Japan. The quality of the contributed oral and poster presentations was also very high. EMAG is keen to encourage student participation, and a winner and two runners-up were presented with prizes for the best oral and poster presentations from a student. 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 you, like me, will be struck by the scientific quality of the 87 papers that follow, and that you will find them interesting and informative. Finally I must thank the platinum sponsors for their support of the meeting. These were Gatan, Zeiss, FEI, JEOL and Hitachi. I must also thank the European Microscopy Society for their generous sponsorship and support for the travel costs of

  17. Four-Dimensional Ultrafast Electron Microscopy: Insights into an Emerging Technique

    KAUST Repository

    Adhikari, Aniruddha

    2016-12-15

    Four-dimensional ultrafast electron microscopy (4D-UEM) is a novel analytical technique that aims to fulfill the long-held dream of researchers to investigate materials at extremely short spatial and temporal resolutions by integrating the excellent spatial resolution of electron microscopes with the temporal resolution of ultrafast femtosecond laser-based spectroscopy. The ingenious use of pulsed photoelectrons to probe surfaces and volumes of materials enables time-resolved snapshots of the dynamics to be captured in a way hitherto impossible by other conventional techniques. The flexibility of 4D-UEM lies in the fact that it can be used in both the scanning (S-UEM) and transmission (UEM) modes depending upon the type of electron microscope involved. While UEM can be employed to monitor elementary structural changes and phase transitions in samples using real-space mapping, diffraction, electron energy-loss spectroscopy, and tomography, S-UEM is well suited to map ultrafast dynamical events on materials surfaces in space and time. This review provides an overview of the unique features that distinguish these techniques and also illustrates the applications of both S-UEM and UEM to a multitude of problems relevant to materials science and chemistry.

  18. Transmission Electron Microscopy of Iron Metal in Almahata Sitta Ureilite

    Science.gov (United States)

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

    2013-01-01

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

  19. 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

  20. The cryo-electron microscopy structure of huntingtin

    Science.gov (United States)

    Guo, Qiang; Bin Huang; Cheng, Jingdong; Seefelder, Manuel; Engler, Tatjana; Pfeifer, Günter; Oeckl, Patrick; Otto, Markus; Moser, Franziska; Maurer, Melanie; Pautsch, Alexander; Baumeister, Wolfgang; Fernández-Busnadiego, Rubén; Kochanek, Stefan

    2018-03-01

    Huntingtin (HTT) is a large (348 kDa) protein that is essential for embryonic development and is involved in diverse cellular activities such as vesicular transport, endocytosis, autophagy and the regulation of transcription. Although an integrative understanding of the biological functions of HTT is lacking, the large number of identified HTT interactors suggests that it serves as a protein-protein interaction hub. Furthermore, Huntington’s disease is caused by a mutation in the HTT gene, resulting in a pathogenic expansion of a polyglutamine repeat at the amino terminus of HTT. However, only limited structural information regarding HTT is currently available. Here we use cryo-electron microscopy to determine the structure of full-length human HTT in a complex with HTT-associated protein 40 (HAP40; encoded by three F8A genes in humans) to an overall resolution of 4 Å. HTT is largely α-helical and consists of three major domains. The amino- and carboxy-terminal domains contain multiple HEAT (huntingtin, elongation factor 3, protein phosphatase 2A and lipid kinase TOR) repeats arranged in a solenoid fashion. These domains are connected by a smaller bridge domain containing different types of tandem repeats. HAP40 is also largely α-helical and has a tetratricopeptide repeat-like organization. HAP40 binds in a cleft and contacts the three HTT domains by hydrophobic and electrostatic interactions, thereby stabilizing the conformation of HTT. These data rationalize previous biochemical results and pave the way for improved understanding of the diverse cellular functions of HTT.

  1. Visualization of Microbial Biomarkers by Scanning Electron Microscopy

    Science.gov (United States)

    Wainwright, Norman R.; Allen, Carlton C.; Child, Alice

    2001-01-01

    . Fortunately, many antimicrobial defense systems of higher organisms require sensitive detection to combat microbial pathogens. We employ here the primitive immune system of the evolutionarily ancient horseshoe crab, Limulus polyphemus. This species relies on multi-enzyme signal amplification detection of cell wall molecules and they can be applied to the development of useful detectors of life. An extension of this work includes the visualization of microbial signatures by labeling LAL components with chromogenic or electron dense markers. The protein Limulus Anti-LPS Factor (LALF) has an extremely high affinity for LPS. By coupling LALF binding with colloidal gold labels we demonstrate a correlation of the structures visible by electron microscopy with biochemical evidence of microbial cell wall materials. Pure silica particles were mixed with cultures of E. coli (10(exp 6) cfu/mL). Samples were washed sequentially with buffered saline, LALF, antibody to LALF and finally colloidal gold-labeled Protein A. Negative controls were not exposed to E. coli but received identical treatment otherwise. Samples were coated with carbon and imaged on a JEOL JSM-840 scanning electron microscope with LaB6 source in the back scatter mode with the JEOL annular back scatter detector. 20 nm-scale black spots in this contrast-reversed image originate from electrons back-scattered by gold atoms. Negative controls did not give any signal. Future work will expand application of this technique to soil simulants and mineralized rock samples.

  2. Study of the localization of iron, ferritin, and hemosiderin in Alzheimer's disease hippocampus by analytical microscopy at the subcellular level.

    Science.gov (United States)

    Quintana, C; Bellefqih, S; Laval, J Y; Guerquin-Kern, J L; Wu, T D; Avila, J; Ferrer, I; Arranz, R; Patiño, C

    2006-01-01

    Previous studies of the structure of core nanocrystals of ferritin (Ft) in the brains of patients with Alzheimer's disease (AD) have shown differences in the mineral compound in comparison with physiological Ft. Both Ft cores have a polyphasic composition but whereas the major phase in physiological Ft is hexagonal ferric iron oxide (ferrihydrite), the major phases in brain AD Ft are two cubic mixed ferric-ferrous iron oxides (magnetite and wüstite). One of these (wüstite) is similar to what is detected in hemosiderin (Hm) cores in primary hemochromatosis (Quintana, C., Cowley, J.M, Marhic, C., 2004. Electron nanodiffraction and high resolution electron microscopy studies of the structure and composition of physiological and pathological ferritin. J. Struct. Biol. 147, 166-178). We have studied, herein, the distribution of iron, Ft, and Hm in sections of AD hippocampus using analytical microscopy. Iron present in Ft cores was directly mapped in a nanoSIMS microscope and the iron distribution has been correlated with the constituent elements N, P, and S. Ft and Hm cores were visualized at an ultrastructural level in an analytical transmission electron microscope. In senile plaques, Ft was observed in the coronal region associated with a non-beta-amyloid component and in the periphery of plaques, together with Hm, in sulfur-rich dense bodies of dystrophic neurites. Hm was also found in lysosomes and siderosomes of glial cells. Ft was observed in the cytoplasm and nucleus of oligodendrocytes. Ft was particularly abundant in myelinated axons in association with oligodendrocyte processes. These findings provide new arguments to support the hypothesis of a dysfunction of Ft (with eventual degradation to Hm) in AD resulting in an increase of toxic brain ferrous ions that may contribute to the production of free radicals that induce both cellular oxidative stress and aged-related myelin breakdown associated with cognitive decline and AD (Bartzokis, G., 2004. Age

  3. Analytical theory of the Bunemann instability for electron runaway

    International Nuclear Information System (INIS)

    Kaeppeler, H.J.

    1988-10-01

    Generally, analytical expressions for the growth rate of the Bunemann instability are given for small ratios of beam density n b to plasma density n p and are derived for zero applied electric field. In the case of this instability caused by runaway electrons, e.g. in the dense plasma focus or z-pinch, there exists an appreciable induced electric field strength and the assumption of n b /n p << 1 can no longer be made. In this report, a simplified dispersion relation including an applied, time-variable electric field is derived and an approximate analytical expression for the temporal growth rate is given. The magnetic field is assumed to be zero. (orig.)

  4. Direct electron imaging in electron microscopy with monolithic active pixel sensors

    Energy Technology Data Exchange (ETDEWEB)

    Deptuch, G. [Brookhaven National Laboratory, Upton, NY 11973 (United States)], E-mail: deptuch@ieee.org; Besson, A. [IPHC, CNRS-IN2P3/ULP, 23 rue du Loess, BP 28, 67037 Strasbourg Cedex 02 (France); Rehak, P. [Brookhaven National Laboratory, Upton, NY 11973 (United States); Szelezniak, M. [IPHC, CNRS-IN2P3/ULP, 23 rue du Loess, BP 28, 67037 Strasbourg Cedex 02 (France); Wall, J. [Brookhaven National Laboratory, Upton, NY 11973 (United States); Winter, M. [IPHC, CNRS-IN2P3/ULP, 23 rue du Loess, BP 28, 67037 Strasbourg Cedex 02 (France); Zhu, Y. [Brookhaven National Laboratory, Upton, NY 11973 (United States)

    2007-08-15

    A new imaging device for dynamic electron microscopy is in great demand. The detector should provide the experimenter with images having sufficient spatial resolution at high speed. Immunity to radiation damage, accumulated during exposures, is critical. Photographic film, a traditional medium, is not adequate for studies that require large volumes of data or rapid recording and charge coupled device (CCD) cameras have limited resolution, due to phosphor screen coupling. CCD chips are not suitable for direct recording due to their extreme sensitivity to radiation damage. This paper discusses characterization of monolithic active pixel sensors (MAPS) in a scanning electron microscope (SEM) as well as in a transmission electron microscope (TEM). The tested devices were two versions of the MIMOSA V (MV) chip. This 1 M pixel device features pixel size of 17x17 {mu}m{sup 2} and was designed in a 0.6 {mu}m CMOS process. The active layer for detection is a thin (less than 20 {mu}m) epitaxial layer, limiting the broadening of the electron beam. The first version of the detector was a standard imager with electronics, passivation and interconnection layers on top of the active region; the second one was bottom-thinned, reaching the epitaxial layer from the bottom. The electron energies used range from a few keV to 30 keV for SEM and from 40 to 400 keV for TEM. Deterioration of the image resolution due to backscattering was quantified for different energies and both detector versions.

  5. High-resolution analytical imaging and electron holography of magnetite particles in amyloid cores of Alzheimer’s disease

    Science.gov (United States)

    Plascencia-Villa, Germán; Ponce, Arturo; Collingwood, Joanna F.; Arellano-Jiménez, M. Josefina; Zhu, Xiongwei; Rogers, Jack T.; Betancourt, Israel; José-Yacamán, Miguel; Perry, George

    2016-01-01

    Abnormal accumulation of brain metals is a key feature of Alzheimer’s disease (AD). Formation of amyloid-β plaque cores (APC) is related to interactions with biometals, especially Fe, Cu and Zn, but their particular structural associations and roles remain unclear. Using an integrative set of advanced transmission electron microscopy (TEM) techniques, including spherical aberration-corrected scanning transmission electron microscopy (Cs-STEM), nano-beam electron diffraction, electron holography and analytical spectroscopy techniques (EDX and EELS), we demonstrate that Fe in APC is present as iron oxide (Fe3O4) magnetite nanoparticles. Here we show that Fe was accumulated primarily as nanostructured particles within APC, whereas Cu and Zn were distributed through the amyloid fibers. Remarkably, these highly organized crystalline magnetite nanostructures directly bound into fibrillar Aβ showed characteristic superparamagnetic responses with saturated magnetization with circular contours, as observed for the first time by off-axis electron holography of nanometer scale particles. PMID:27121137

  6. Morphology and ultrastructure of Siberian sturgeon (Acipenser baerii) spermatozoa using scanning and transmission electron microscopy

    Czech Academy of Sciences Publication Activity Database

    Pšenička, M.; Hadi Alavi, S.M.; Rodina, M.; Gela, D.; Nebesářová, Jana; Linhart, O.

    2007-01-01

    Roč. 99, č. 2 (2007), s. 103-115 ISSN 0248-4900 R&D Projects: GA ČR GA524/06/0817 Institutional research plan: CEZ:AV0Z60220518 Keywords : acrosome * flagellum * scanning electron microscopy * Siberian sturgeon * Acipenser baerii * spermatozoon , * transmission electron microscopy Subject RIV: ED - Physiology Impact factor: 3.752, year: 2007

  7. 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...

  8. 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

  9. 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...

  10. Finite-size effects and analytical modeling of electrostatic force microscopy applied to dielectric films.

    Science.gov (United States)

    Gomila, G; Gramse, G; Fumagalli, L

    2014-06-27

    A numerical analysis of the polarization force between a sharp conducting probe and a dielectric film of finite lateral dimensions on a metallic substrate is presented with the double objective of (i) determining the conditions under which the film can be approximated by a laterally infinite film and (ii) proposing an analytical model valid in this limit. We show that, for a given dielectric film, the critical diameter above which the film can be modeled as laterally infinite depends not only on the probe geometry, as expected, but mainly on the film thickness. In particular, for films with intermediate to large thicknesses (>100 nm), the critical diameter is nearly independent from the probe geometry and essentially depends on the film thickness and dielectric constant following a relatively simple phenomenological expression. For films that can be considered as laterally infinite, we propose a generalized analytical model valid in the thin-ultrathin limit (<20-50 nm) that reproduces the numerical calculations and the experimental data. Present results provide a general framework under which accurate quantification of electrostatic force microscopy measurements on dielectric films on metallic substrates can be achieved.

  11. Accurate virus quantitation using a Scanning Transmission Electron Microscopy (STEM) detector in a scanning electron microscope.

    Science.gov (United States)

    Blancett, Candace D; Fetterer, David P; Koistinen, Keith A; Morazzani, Elaine M; Monninger, Mitchell K; Piper, Ashley E; Kuehl, Kathleen A; Kearney, Brian J; Norris, Sarah L; Rossi, Cynthia A; Glass, Pamela J; Sun, Mei G

    2017-10-01

    A method for accurate quantitation of virus particles has long been sought, but a perfect method still eludes the scientific community. Electron Microscopy (EM) quantitation is a valuable technique because it provides direct morphology information and counts of all viral particles, whether or not they are infectious. In the past, EM negative stain quantitation methods have been cited as inaccurate, non-reproducible, and with detection limits that were too high to be useful. To improve accuracy and reproducibility, we have developed a method termed Scanning Transmission Electron Microscopy - Virus Quantitation (STEM-VQ), which simplifies sample preparation and uses a high throughput STEM detector in a Scanning Electron Microscope (SEM) coupled with commercially available software. In this paper, we demonstrate STEM-VQ with an alphavirus stock preparation to present the method's accuracy and reproducibility, including a comparison of STEM-VQ to viral plaque assay and the ViroCyt Virus Counter. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  12. 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.

  13. A carbon nanotube tape for serial-section electron microscopy of brain ultrastructure.

    Science.gov (United States)

    Kubota, Yoshiyuki; Sohn, Jaerin; Hatada, Sayuri; Schurr, Meike; Straehle, Jakob; Gour, Anjali; Neujahr, Ralph; Miki, Takafumi; Mikula, Shawn; Kawaguchi, Yasuo

    2018-01-30

    Automated tape-collecting ultramicrotomy in conjunction with scanning electron microscopy (SEM) is a powerful approach for volume electron microscopy and three-dimensional neuronal circuit analysis. Current tapes are limited by section wrinkle formation, surface scratches and sample charging during imaging. Here we show that a plasma-hydrophilized carbon nanotube (CNT)-coated polyethylene terephthalate (PET) tape effectively resolves these issues and produces SEM images of comparable quality to those from transmission electron microscopy. CNT tape can withstand multiple rounds of imaging, offer low surface resistance across the entire tape length and generate no wrinkles during the collection of ultrathin sections. When combined with an enhanced en bloc staining protocol, CNT tape-processed brain sections reveal detailed synaptic ultrastructure. In addition, CNT tape is compatible with post-embedding immunostaining for light and electron microscopy. We conclude that CNT tape can enable high-resolution volume electron microscopy for brain ultrastructure analysis.

  14. Method for local temperature measurement in a nanoreactor for in situ high-resolution electron microscopy.

    Science.gov (United States)

    Vendelbo, S B; Kooyman, P J; Creemer, J F; Morana, B; Mele, L; Dona, P; Nelissen, B J; Helveg, S

    2013-10-01

    In situ high-resolution transmission electron microscopy (TEM) of solids under reactive gas conditions can be facilitated by microelectromechanical system devices called nanoreactors. These nanoreactors are windowed cells containing nanoliter volumes of gas at ambient pressures and elevated temperatures. However, due to the high spatial confinement of the reaction environment, traditional methods for measuring process parameters, such as the local temperature, are difficult to apply. To address this issue, we devise an electron energy loss spectroscopy (EELS) method that probes the local temperature of the reaction volume under inspection by the electron beam. The local gas density, as measured using quantitative EELS, is combined with the inherent relation between gas density and temperature, as described by the ideal gas law, to obtain the local temperature. Using this method we determined the temperature gradient in a nanoreactor in situ, while the average, global temperature was monitored by a traditional measurement of the electrical resistivity of the heater. The local gas temperatures had a maximum of 56 °C deviation from the global heater values under the applied conditions. The local temperatures, obtained with the proposed method, are in good agreement with predictions from an analytical model. Copyright © 2013 Elsevier B.V. All rights reserved.

  15. Fast imaging with inelastically scattered electrons by off-axis chromatic confocal electron microscopy.

    Science.gov (United States)

    Zheng, Changlin; Zhu, Ye; Lazar, Sorin; Etheridge, Joanne

    2014-04-25

    We introduce off-axis chromatic scanning confocal electron microscopy, a technique for fast mapping of inelastically scattered electrons in a scanning transmission electron microscope without a spectrometer. The off-axis confocal mode enables the inelastically scattered electrons to be chromatically dispersed both parallel and perpendicular to the optic axis. This enables electrons with different energy losses to be separated and detected in the image plane, enabling efficient energy filtering in a confocal mode with an integrating detector. We describe the experimental configuration and demonstrate the method with nanoscale core-loss chemical mapping of silver (M4,5) in an aluminium-silver alloy and atomic scale imaging of the low intensity core-loss La (M4,5@840  eV) signal in LaB6. Scan rates up to 2 orders of magnitude faster than conventional methods were used, enabling a corresponding reduction in radiation dose and increase in the field of view. If coupled with the enhanced depth and lateral resolution of the incoherent confocal configuration, this offers an approach for nanoscale three-dimensional chemical mapping.

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

    International Nuclear Information System (INIS)

    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 0 C, and was found to be approximately five times greater at -120 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

  17. 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.

  18. 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

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

    Science.gov (United States)

    Wang, Peng; Behan, Gavin; Kirkland, Angus I; Nellist, Peter D; Cosgriff, Eireann C; D'Alfonso, Adrian J; Morgan, Andrew J; Allen, Leslie J; Hashimoto, Ayako; Takeguchi, Masaki; Mitsuishi, Kazutaka; Shimojo, Masayuki

    2011-06-01

    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. Copyright © 2010 Elsevier B.V. All rights reserved.

  20. Implementing electronic health care predictive analytics: considerations and challenges.

    Science.gov (United States)

    Amarasingham, Ruben; Patzer, Rachel E; Huesch, Marco; Nguyen, Nam Q; Xie, Bin

    2014-07-01

    The use of predictive modeling for real-time clinical decision making is increasingly recognized as a way to achieve the Triple Aim of improving outcomes, enhancing patients' experiences, and reducing health care costs. The development and validation of predictive models for clinical practice is only the initial step in the journey toward mainstream implementation of real-time point-of-care predictions. Integrating electronic health care predictive analytics (e-HPA) into the clinical work flow, testing e-HPA in a patient population, and subsequently disseminating e-HPA across US health care systems on a broad scale require thoughtful planning. Input is needed from policy makers, health care executives, researchers, and practitioners as the field evolves. This article describes some of the considerations and challenges of implementing e-HPA, including the need to ensure patients' privacy, establish a health system monitoring team to oversee implementation, incorporate predictive analytics into medical education, and make sure that electronic systems do not replace or crowd out decision making by physicians and patients. Project HOPE—The People-to-People Health Foundation, Inc.

  1. 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.

  2. Structure studies by electron microscopy and electron diffraction at Physics Department, University of Oslo, 1976-1985

    International Nuclear Information System (INIS)

    Gjoennes, J.K.; Olsen, A.

    1985-08-01

    The paper describes the reasearch activities and plans at the electron microscopy laboratorium, Physics Departmen, University of Oslo. Since the first electron microscope was installed in 1968, the research has covered inorganic structures, physical metallurgy, as well as theory of electron scattering and the development of methods in this field. The current plans involve efforts in the development of crystallographic and spectroscopic methods

  3. 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.

  4. 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.

  5. 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.

  6. Development of a fountain detector for spectroscopy of secondary electrons in scanning electron microscopy

    Science.gov (United States)

    Agemura, Toshihide; Kimura, Takashi; Sekiguchi, Takashi

    2018-04-01

    The low-pass secondary electron (SE) detector, the so-called “fountain detector (FD)”, for scanning electron microscopy has high potential for application to the imaging of low-energy SEs. Low-energy SE imaging may be used for detecting the surface potential variations of a specimen. However, the detected SEs include a certain fraction of tertiary electrons (SE3s) because some of the high-energy backscattered electrons hit the grid to yield SE3s. We have overcome this difficulty by increasing the aperture ratio of the bias and ground grids and using the lock-in technique, in which the AC field with the DC offset was applied on the bias grid. The energy-filtered SE images of a 4H-SiC p–n junction show complex behavior according to the grid bias. These observations are clearly explained by the variations of Auger spectra across the p–n junction. The filtered SE images taken with the FD can be applied to observing the surface potential variation of specimens.

  7. Quantifying Chemical and Electrochemical Reactions in Liquids by in situ Electron Microscopy

    DEFF Research Database (Denmark)

    Canepa, Silvia

    and developing a robust imaging analysis method for quantitatively understand chemical and electrochemical process during in situ liquid electron microscopy. By using two custom-made liquid cells (an electrochemical scanning electron microscopy (EC-SEM) platform and Liquid Flow S/TEM holder) beam...... 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...

  8. Analysis of individual environmental particles using modern methods of electron microscopy and X-ray microanalysis

    International Nuclear Information System (INIS)

    Laskin, A.; Cowin, J.P.; Iedema, M.J.

    2006-01-01

    Understanding the composition of particles in the atmosphere is critical because of their health effects and their direct and indirect effects on radiative forcing, and hence on climate. In this manuscript, we demonstrate the utility of single particle off-line analysis to investigate the chemistry of individual atmospheric particles using modern, state-of-the-art electron microscopy and time-of-flight secondary ionization mass spectrometry techniques. We show that these methods provide specific, detailed data on particle composition, chemistry, morphology, phase and internal structure. This information is crucial for evaluating hygroscopic properties of aerosols, understanding aerosol aging and reactivity, and correlating the characteristics of aerosols with their optical properties. The manuscript presents a number of analytical advances in methods of electron probe particle analysis along with a brief review of a number of the research projects carried out in the authors' laboratory on the chemical characterization of environmental particles. The obtained data offers a rich set of qualitative and quantitative information on the particle chemistry, composition and the mechanisms of gas-particle interactions which are of high importance to atmospheric processes involving particulate matter and air pollution

  9. 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...

  10. 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.

  11. Engineering Electrochemical Setups for Electron Microscopy of Liquid Processes

    DEFF Research Database (Denmark)

    Jensen, Eric; Burrows, Andrew

    This work focuses on creating tools for imaging liquid samples at atmospheric pressure and room temperature in two different electron microscopes; the scanning electron microscope (SEM) and the transmission electron microscope (TEM). The main focus of the project was the fabrication of the two sy......-SEM cell. In TEM, holography of graphene multi-layer sheets has been performed and the phase change per sheet has been determined as a step towards in-situ holography of liquid through graphene.......-transparent window and built-in electrodes was placed above a reservoir, sealing off the liquid from the vacuum, but allowing imaging through the window in the chip. In-situ electrochemical experiments have been performed with this setup: imaging the electron beam (e-beam) deposition of nickel on the window......This work focuses on creating tools for imaging liquid samples at atmospheric pressure and room temperature in two different electron microscopes; the scanning electron microscope (SEM) and the transmission electron microscope (TEM). The main focus of the project was the fabrication of the two...

  12. 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...

  13. Comparison of the decameric structure of peroxiredoxin-II by transmission electron microscopy and X-ray crystallography

    DEFF Research Database (Denmark)

    Harris, J. Robin; Schröder, Ewald; Isupov, Michail N.

    2001-01-01

    Peroxiredoxin; Transmission electron microscopy; X-ray structure; Negative staining; angular reconstitution; Molecular fitting......Peroxiredoxin; Transmission electron microscopy; X-ray structure; Negative staining; angular reconstitution; Molecular fitting...

  14. The Analytic Information Warehouse (AIW): a Platform for Analytics using Electronic Health Record Data

    Science.gov (United States)

    Post, Andrew R.; Kurc, Tahsin; Cholleti, Sharath; Gao, Jingjing; Lin, Xia; Bornstein, William; Cantrell, Dedra; Levine, David; Hohmann, Sam; Saltz, Joel H.

    2013-01-01

    Objective To create an analytics platform for specifying and detecting clinical phenotypes and other derived variables in electronic health record (EHR) data for quality improvement investigations. Materials and Methods We have developed an architecture for an Analytic Information Warehouse (AIW). It supports transforming data represented in different physical schemas into a common data model, specifying derived variables in terms of the common model to enable their reuse, computing derived variables while enforcing invariants and ensuring correctness and consistency of data transformations, long-term curation of derived data, and export of derived data into standard analysis tools. It includes software that implements these features and a computing environment that enables secure high-performance access to and processing of large datasets extracted from EHRs. Results We have implemented and deployed the architecture in production locally. The software is available as open source. We have used it as part of hospital operations in a project to reduce rates of hospital readmission within 30 days. The project examined the association of over 100 derived variables representing disease and co-morbidity phenotypes with readmissions in five years of data from our institution’s clinical data warehouse and the UHC Clinical Database (CDB). The CDB contains administrative data from over 200 hospitals that are in academic medical centers or affiliated with such centers. Discussion and Conclusion A widely available platform for managing and detecting phenotypes in EHR data could accelerate the use of such data in quality improvement and comparative effectiveness studies. PMID:23402960

  15. The Analytic Information Warehouse (AIW): a platform for analytics using electronic health record data.

    Science.gov (United States)

    Post, Andrew R; Kurc, Tahsin; Cholleti, Sharath; Gao, Jingjing; Lin, Xia; Bornstein, William; Cantrell, Dedra; Levine, David; Hohmann, Sam; Saltz, Joel H

    2013-06-01

    To create an analytics platform for specifying and detecting clinical phenotypes and other derived variables in electronic health record (EHR) data for quality improvement investigations. We have developed an architecture for an Analytic Information Warehouse (AIW). It supports transforming data represented in different physical schemas into a common data model, specifying derived variables in terms of the common model to enable their reuse, computing derived variables while enforcing invariants and ensuring correctness and consistency of data transformations, long-term curation of derived data, and export of derived data into standard analysis tools. It includes software that implements these features and a computing environment that enables secure high-performance access to and processing of large datasets extracted from EHRs. We have implemented and deployed the architecture in production locally. The software is available as open source. We have used it as part of hospital operations in a project to reduce rates of hospital readmission within 30days. The project examined the association of over 100 derived variables representing disease and co-morbidity phenotypes with readmissions in 5years of data from our institution's clinical data warehouse and the UHC Clinical Database (CDB). The CDB contains administrative data from over 200 hospitals that are in academic medical centers or affiliated with such centers. A widely available platform for managing and detecting phenotypes in EHR data could accelerate the use of such data in quality improvement and comparative effectiveness studies. Copyright © 2013 Elsevier Inc. All rights reserved.

  16. Lights Will Guide You : Sample Preparation and Applications for Integrated Laser and Electron Microscopy

    NARCIS (Netherlands)

    Karreman, M.A.

    2013-01-01

    Correlative microscopy is the combined use of two different forms of microscopy in the study of a specimen, allowing for the exploitation of the advantages of both imaging tools. The integrated Laser and Electron Microscope (iLEM), developed at Utrecht University, combines a fluorescence microscope

  17. 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.

  18. Some applications of ballistic electron emission microscopy/spectroscopy

    Czech Academy of Sciences Publication Activity Database

    Walachová, Jarmila

    1998-01-01

    Roč. 93, č. 2 (1998), s. 365-372 ISSN 0587-4246. [Scanning Probe Spectroscopy and Related Methods - SPS'97 /1./. Poznan, 15.07.1997-18.07.1997] R&D Projects: GA ČR GA102/97/0427 Keywords : field emission electron microscopes * nanostructured materials * Schottky effect Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 0.344, year: 1998

  19. In situ transmission electron microscopy of light-induced photocatalytic reactions

    DEFF Research Database (Denmark)

    Cavalca, Filippo; Laursen, Anders Bo; Kardynal, Beata

    2012-01-01

    Transmission electron microscopy (TEM) makes it possible to obtain insight into the structure, composition and reactivity of photocatalysts, which are of fundamental interest for sustainable energy research. Such insight can be used for further material optimization. Here, we combine conventional...

  20. In vivo degradation of processed dermal sheep collagen evaluated with transmission electron microscopy

    NARCIS (Netherlands)

    van Wachem, P.B.; van Luyn, M.J.A.; Nieuwenhuis, P.; Koerten, H.K.; Olde damink, L.H.H.; Olde-Damink, L.; ten Hoopen, Hermina W.M.; Feijen, Jan

    1991-01-01

    The in vivo degradation of hexamethylenediisocyanate-tanned dermal sheep collagen was studied with transmission electron microscopy. Discs of hexamethylenediisocyanate-tanned dermal sheep collagen were subcutaneously implanted in rats. Both an intra- and an extracellular route of degradation could

  1. INVIVO DEGRADATION OF PROCESSED DERMAL SHEEP COLLAGEN EVALUATED WITH TRANSMISSION ELECTRON-MICROSCOPY

    NARCIS (Netherlands)

    VANWACHEM, PB; VANLUYN, MJA; NIEUWENHUIS, P; KOERTEN, HK; DAMINK, LO; TENHOOPEN, H; FEIJEN, J

    The in vivo degradation of hexamethylenediisocyanate-tanned dermal sheep collagen was studied with transmission electron microscopy. Discs of hexamethylenediisocyanate-tanned dermal sheep collagen were subcutaneously implanted in rats. Both an intra- and an extracellular route of degradation could

  2. 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

  3. Quantitative detection of gold nanoparticles on individual, unstained cancer cells by scanning electron microscopy

    NARCIS (Netherlands)

    Hartsuiker, L.; van Es, P.; Petersen, W.; van Leeuwen, T. G.; Terstappen, L. W. M. M.; Otto, C.

    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

  4. Abstracts of the 9. Colloquium of the Brazilian Society of Electron Microscopy

    International Nuclear Information System (INIS)

    1983-01-01

    A set of abstracts is presented, reporting the use of electron microscopy for the study of: crystal structures and defects; corrosion on several metal alloys; ultrastructural changes in biological materials. (C.L.B.) [pt

  5. Transmission Electron Microscopy Study of Individual Carbon Nanotube Breakdown Caused by Joule Heating in Air

    DEFF Research Database (Denmark)

    Mølhave, Kristian; Gudnason, S.B.; Pedersen, Anders Tegtmeier

    2006-01-01

    We present repeated structural and electrical measurements on individual multiwalled carbon nanotubes, alternating between electrical measurements under ambient conditions and transmission electron microscopy (TEM). The multiwalled carbon nanotubes made by chemical vapor deposition were manipulated...

  6. 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

  7. Automated magnification calibration in transmission electron microscopy using Fourier analysis of replica images.

    NARCIS (Netherlands)

    Laak, J.A.W.M. van der; Dijkman, H.B.P.M.; Pahlplatz, M.M.M.

    2006-01-01

    The magnification factor in transmission electron microscopy is not very precise, hampering for instance quantitative analysis of specimens. Calibration of the magnification is usually performed interactively using replica specimens, containing line or grating patterns with known spacing. In the

  8. [Bacterial localization in apical cementum at the epithelial insertion using scanning electron microscopy].

    Science.gov (United States)

    García Núñez, J A; Herrera, I; Cerezo Lapiedra, R; Santa María, I

    1989-02-01

    Extracted teeth due to consequence of chronic periodontitis of adult are fractured and the apical cementum to junction epithelium is examined under S.E.M. (scanning electron microscopy) being found bacterias forms inside niches of the apical cementum.

  9. 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...

  10. Proton induced X-ray emission and electron microscopy analysis of induced mutants of sorghum

    CSIR Research Space (South Africa)

    Mbambo, Z

    2014-01-01

    Full Text Available of elements in preferential accumulation tissues and entire changes in cellular localization. Transmission and scanning electron microscopy of the mutants resolved changes in size, shape, ultra-structure and packed cell volumes of protein- and starch bodies...

  11. 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

    2017-12-01

    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.

  12. 2. Brazilian Congress on Cell Biology and 7. Brazilian Colloquium on Electron Microscopy - Abstracts

    International Nuclear Information System (INIS)

    1980-01-01

    Immunology, virology, bacteriology, genetics and protozoology are some of the subjects treated in the 2. Brazilian Congress on Cell Biology. Studies using radioisotopic techniques and ultrastructural cytological studies are presented. Use of optical - and electron microscopy in some of these studies is discussed. In the 7. Brazilian Colloquium on Electron Microscopy, the application of this technique to materials science is discussed (failure analysis in metallurgy, energy dispersion X-ray analysis, etc). (I.C.R.) [pt

  13. Electron microscopy of crystalline solids and non-classical crystal growth

    OpenAIRE

    Greer, Heather Frances

    2013-01-01

    This project concerns the non-classical crystal growth of various porous and non-porous materials. In order to determine their crystal growth mechanism, the reaction was stopped at several different reaction times with the size, morphology, crystal structure and orientation of the particles analysed using scanning electron microscopy and high resolution transmission electron microscopy as the principal characterisation techniques. Other techniques used include X-ray diffraction, energy disper...

  14. Analytic representation of electron central-axis depth dose data

    International Nuclear Information System (INIS)

    Jette, D.; Lanzl, L.H.; Rozenfeld, M.; Pagnamenta, A.

    1981-01-01

    We have examined a number of analytic representations of electron central-axis depth dose data current in the literature, testing them against sets of standard depth dose data. One of them, a two-parameter model of Shabason and Hendee, is recommended in situations in which good accuracy (approx.2%) is desired, with the values of the parameters determined by an approximation formula which we have developed elsewhere. For higher accuracy, we have developed a polynomial model which gives, typically, a standard deviation of the fitting polynomial from the data points of 1%, and a maximum deviation of 2%. Fitting polynomials obtained with this method possess the property of having zero slope at the position of actual maximum dose, and generally a fifth-order polynomial (requiring four nonzero coefficients) provided the most acceptable fit. The four parameters involved are determined through inversion of a 4 x 4 matrix, and we have tabulated these four coefficients for the standard data sets. The polynomial model is designed for interpolation in the range between the 100% dose depth and the 10% dose depth, and another fitting curve of the same type can be adjoined to cover depths less than the 100% dose depth. Key words: electron teletherapy, central-axis depth dose, polynomial model, interpolation

  15. Modern electron microscopy resolved in space, energy and time

    Science.gov (United States)

    Carbone, F.

    2011-06-01

    Recent pioneering experiments combining ultrafast lasers with electron-based technology demonstrated the possibility to obtain real-time information about chemical bonds and their dynamics during reactions and phase transformation. These techniques have been successfully applied to several states of matter including gases, liquids, solids and biological samples showing a unique versatility thanks to the high sensitivity of electrons to tiny amounts of material and their low radiation damage. A very powerful tool, the time-resolved Transmission Electron Microscope (TEM), is capable of delivering information on the structure of ordered and disordered matter through diffraction and imaging, with a spatial resolution down to the atomic limit (10-10 m); the same apparatus can distinguish dynamical phenomena happening on the time-scales between fs and ms, with a dynamic range of 12 orders of magnitude. At the same time, spectroscopic information can be obtained from the loss of kinetic energy of electrons interacting with specimens in the range of interband transitions and plasmons in solids, or charge transfers in molecules, all the way up to the atomic core levels with the same time-resolution. In this contribution, we focus on the recent advances in fs Electron Energy Loss Spectroscopy (FEELS), discussing the main results and their implications for future studies.

  16. 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.

  17. 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.

  18. Structural studies of glasses by transmission electron microscopy and electron diffraction

    International Nuclear Information System (INIS)

    Kashchieva, E.P.

    1997-01-01

    The purpose of this work is to present information about the applications of transmission electron microscopy (TEM) and electron diffraction (ED) for structural investigations of glasses. TEM investigations have been carried out on some binary and on a large number of ternary borate-telluride systems where glass-forming oxides, oxides of transitional elements and modified oxides of elements from I, II and III groups in the periodic table, are used as third component. The large experimental data given by TEM method allows the fine classification of the micro-heterogeneities. A special case of micro-heterogeneous structure with technological origin occurs near the boundary between the 2 immiscible liquids obtained at macro-phase separation. TEM was also used for the direct observation of the glass structure and we have studied the nano-scale structure of borate glasses obtained at slow and fast cooling of the melts. The ED possesses advantages for analysis of amorphous thin films or micro-pastilles and it is a very useful technique for study in materials containing simultaneously light and heavy elements. A comparison between the possibilities of the 3 diffraction techniques (X-ray diffraction, neutron diffraction and ED) is presented

  19. 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...... 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....

  20. 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.

  1. Observation of Magnetic Induction Distribution by Scanning Interference Electron Microscopy

    Science.gov (United States)

    Takahashi, Yoshio; Yajima, Yusuke; Ichikawa, Masakazu; Kuroda, Katsuhiro

    1994-09-01

    A scanning interference electron microscope (SIEM) capable of observing magnetic induction distribution with high sensitivity and spatial resolution has been developed. The SIEM uses a pair of fine coherent scanning probes and detects their relative phase change by magnetic induction, giving raster images of microscopic magnetic distributions. Its performance has been demonstrated by observing magnetic induction distributed near the edge of a recorded magnetic storage medium. Obtained images are compared with corresponding images taken in the scanning Lorentz electron microscope mode using the same microscope, and the differences between them are discussed.

  2. Quantitating morphological changes in biological samples during scanning electron microscopy sample preparation with correlative super-resolution microscopy.

    Science.gov (United States)

    Zhang, Ying; Huang, Tao; Jorgens, Danielle M; Nickerson, Andrew; Lin, Li-Jung; Pelz, Joshua; Gray, Joe W; López, Claudia S; Nan, Xiaolin

    2017-01-01

    Sample preparation is critical to biological electron microscopy (EM), and there have been continuous efforts on optimizing the procedures to best preserve structures of interest in the sample. However, a quantitative characterization of the morphological changes associated with each step in EM sample preparation is currently lacking. Using correlative EM and superresolution microscopy (SRM), we have examined the effects of different drying methods as well as osmium tetroxide (OsO4) post-fixation on cell morphology during scanning electron microscopy (SEM) sample preparation. Here, SRM images of the sample acquired under hydrated conditions were used as a baseline for evaluating morphological changes as the sample went through SEM sample processing. We found that both chemical drying and critical point drying lead to a mild cellular boundary retraction of ~60 nm. Post-fixation by OsO4 causes at least 40 nm additional boundary retraction. We also found that coating coverslips with adhesion molecules such as fibronectin prior to cell plating helps reduce cell distortion from OsO4 post-fixation. These quantitative measurements offer useful information for identifying causes of cell distortions in SEM sample preparation and improving current procedures.

  3. Investigation of the structure of nanocrystalline refractory oxides by X-ray diffraction, electron microscopy, and atomic force microscopy

    International Nuclear Information System (INIS)

    Ulyanova, T. M.; Titova, L. V.; Medichenko, S. V.; Zonov, Yu. G.; Konstantinova, T. E.; Glazunova, V. A.; Doroshkevich, A. S.; Kuznetsova, T. A.

    2006-01-01

    The structures of nanocrystalline fibrous powders of refractory oxides have been investigated by different methods: determination of coherent-scattering regions, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and atomic-force microscopy (AFM). The sizes of nanograins of different crystalline phases of refractory metal oxides have been determined during the formation of these nanograins and the dynamics of their growth during heat treatment in the temperature range 600-1600 deg. C has been studied. The data on the structure of nanocrystalline refractory oxide powders, obtained by different methods, are in good agreement. According to the data on coherent-scattering regions, the sizes of the ZrO 2 (Y 2 O 3 ) and Al 2 O 3 grains formed are in the range 4-6 nm, and the particle sizes determined according to the TEM and AFM data are in the ranges 5-7 and 2-10 nm, respectively. SEM analysis made it possible to investigate the dynamics of nanoparticle growth at temperatures above 1000 deg. C and establish the limiting temperatures of their consolidation in fibers

  4. A rapid method of reprocessing for electronic microscopy of cut histological in paraffin

    International Nuclear Information System (INIS)

    Hernandez Chavarri, F.; Vargas Montero, M.; Rivera, P.; Carranza, A.

    2000-01-01

    A simple and rapid method is described for re-processing of light microscopy paraffin sections to observe they under transmission electron microscopy (TEM) and scanning electron microscopy (SEM) The paraffin-embedded tissue is sectioned and deparaffinized in toluene; then exposed to osmium vapor under microwave irradiation using a domestic microwave oven. The tissues were embedded in epoxy resin, polymerized and ultrathin sectioned. The method requires a relatively short time (about 30 minutes for TEM and 15 for SEM), and produces a reasonable quality of the ultrastructure for diagnostic purposes. (Author) [es

  5. 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...

  6. A Comparative Scanning Electron Microscopy Evaluation of Smear ...

    African Journals Online (AJOL)

    2018-02-07

    Feb 7, 2018 ... The aim of the present study was to compare the efficacy of chitosan and MTAD for the smear layer removal from the root canal through a scanning electron microscope (SEM). Thirty teeth were randomly divided into three groups according to the final irrigants: 0.2% chitosan, MTAD, saline (control group).

  7. A Comparative Scanning Electron Microscopy Evaluation of Smear ...

    African Journals Online (AJOL)

    The aim of the present study was to compare the efficacy of chitosan and MTAD for the smear layer removal from the root canal through a scanning electron microscope (SEM). Thirty teeth were randomly divided into three groups according to the final irrigants: 0.2% chitosan, MTAD, saline (control group). After the ...

  8. 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

  9. Bulk sensitive hard x-ray photoemission electron microscopy.

    Science.gov (United States)

    Patt, M; Wiemann, C; Weber, N; Escher, M; Gloskovskii, A; Drube, W; Merkel, M; Schneider, C M

    2014-11-01

    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 SrTiO3 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.

  10. New Environmental Scanning Electron Microscopy and Observation of Live Nature

    Czech Academy of Sciences Publication Activity Database

    Neděla, Vilém; Tihlaříková, Eva; Shiojiri, M.

    2013-01-01

    Roč. 6, 1-2 (2013), s. 1-5 ISSN 2228-9038 R&D Projects: GA ČR GAP102/10/1410; GA MŠk EE.2.3.20.0103 Institutional support: RVO:68081731 Keywords : ESEM * detection systems * methodology * live samples Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

  11. 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.

  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. 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.

  14. 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.

  15. Analytical Model of the Nonlinear Dynamics of Cantilever Tip-Sample Surface Interactions for Various Acoustic-Atomic Force Microscopies

    Science.gov (United States)

    Cantrell, John H., Jr.; Cantrell, Sean A.

    2008-01-01

    A comprehensive analytical model of the interaction of the cantilever tip of the atomic force microscope (AFM) with the sample surface is developed that accounts for the nonlinearity of the tip-surface interaction force. The interaction is modeled as a nonlinear spring coupled at opposite ends to linear springs representing cantilever and sample surface oscillators. The model leads to a pair of coupled nonlinear differential equations that are solved analytically using a standard iteration procedure. Solutions are obtained for the phase and amplitude signals generated by various acoustic-atomic force microscope (A-AFM) techniques including force modulation microscopy, atomic force acoustic microscopy, ultrasonic force microscopy, heterodyne force microscopy, resonant difference-frequency atomic force ultrasonic microscopy (RDF-AFUM), and the commonly used intermittent contact mode (TappingMode) generally available on AFMs. The solutions are used to obtain a quantitative measure of image contrast resulting from variations in the Young modulus of the sample for the amplitude and phase images generated by the A-AFM techniques. Application of the model to RDF-AFUM and intermittent soft contact phase images of LaRC-cp2 polyimide polymer is discussed. The model predicts variations in the Young modulus of the material of 24 percent from the RDF-AFUM image and 18 percent from the intermittent soft contact image. Both predictions are in good agreement with the literature value of 21 percent obtained from independent, macroscopic measurements of sheet polymer material.

  16. Comparative morphology of zebra (Dreissena polymorpha) and quagga (Dreissena bugensis) mussel sperm: Light and electron microscopy

    Science.gov (United States)

    Walker, G.K.; Black, M.G.; Edwards, C.A.

    1996-01-01

    Adult zebra (Dreissena polymorpha) and quagga (Dreissena bugensis) mussels were induced to release large quantities of live spermatozoa by the administration of 5-hydroxytryptamine (serotonin). Sperm were photographed alive using phase-contrast microscopy and were fixed subsequently with glutaraldehyde followed by osmium tetroxide for eventual examination by transmission or scanning electron microscopy. The sperm of both genera are of the ect-aquasperm type. Their overall dimensions and shape allow for easy discrimination at the light and scanning electron microscopy level. Transmission electron microscopy of the cells reveals a barrel-shaped nucleus in zebra mussel sperm and an elongated nucleus in quagga mussel sperm. In both species, an acrosome is cradled in a nuclear fossa. The ultrastructure of the acrosome and axial body, however, is distinctive for each species. The structures of the midpiece are shown, including a unique mitochondrial "skirt" that includes densely packed parallel cristae and extends in a narrow sheet from the mitochondria.

  17. 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.

  18. In situ tensile testing of nanofibers by combining atomic force microscopy and scanning electron microscopy

    Science.gov (United States)

    Hang, Fei; Lu, Dun; Bailey, Russell J.; Jimenez-Palomar, Ines; Stachewicz, Urszula; Cortes-Ballesteros, Beatriz; Davies, Martin; Zech, Martin; Bödefeld, Christoph; Barber, Asa H.

    2011-09-01

    A nanomechanical testing set-up is developed by integrating an atomic force microscope (AFM) for force measurements with a scanning electron microscope (SEM) to provide imaging capabilities. Electrospun nanofibers of polyvinyl alcohol (PVA), nylon-6 and biological mineralized collagen fibrils (MCFs) from antler bone were manipulated and tensile-tested using the AFM-SEM set-up. The complete stress-strain behavior to failure of individual nanofibers was recorded and a diversity of mechanical properties observed, highlighting how this technique is able to elucidate mechanical behavior due to structural composition at nanometer length scales.

  19. Image processing of small protein-crystals in electron microscopy

    International Nuclear Information System (INIS)

    Feinberg, D.A.

    1978-11-01

    This electron microscope study was undertaken to determine whether high resolution reconstructed images could be obtained from statistically noisy micrographs by the super-position of several small areas of images of well-ordered crystals of biological macromolecules. Methods of rotational and translational alignment which use Fourier space data were demonstrated to be superior to methods which use Real space image data. After alignment, the addition of the diffraction patterns of four small areas did not produce higher resolution because of unexpected image distortion effects. A method was developed to determine the location of the distortion origin and the coefficients of spiral distortion and pincushion/barrel distortion in order to make future correction of distortions in electron microscope images of large area crystals

  20. Image processing of small protein-crystals in electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Feinberg, D.A.

    1978-11-01

    This electron microscope study was undertaken to determine whether high resolution reconstructed images could be obtained from statistically noisy micrographs by the super-position of several small areas of images of well-ordered crystals of biological macromolecules. Methods of rotational and translational alignment which use Fourier space data were demonstrated to be superior to methods which use Real space image data. After alignment, the addition of the diffraction patterns of four small areas did not produce higher resolution because of unexpected image distortion effects. A method was developed to determine the location of the distortion origin and the coefficients of spiral distortion and pincushion/barrel distortion in order to make future correction of distortions in electron microscope images of large area crystals.

  1. Electron tomography of HEK293T cells using scanning electron microscope-based scanning transmission electron microscopy.

    Science.gov (United States)

    You, Yun-Wen; Chang, Hsun-Yun; Liao, Hua-Yang; Kao, Wei-Lun; Yen, Guo-Ji; Chang, Chi-Jen; Tsai, Meng-Hung; Shyue, Jing-Jong

    2012-10-01

    Based on a scanning electron microscope operated at 30 kV with a homemade specimen holder and a multiangle solid-state detector behind the sample, low-kV scanning transmission electron microscopy (STEM) is presented with subsequent electron tomography for three-dimensional (3D) volume structure. Because of the low acceleration voltage, the stronger electron-atom scattering leads to a stronger contrast in the resulting image than standard TEM, especially for light elements. Furthermore, the low-kV STEM yields less radiation damage to the specimen, hence the structure can be preserved. In this work, two-dimensional STEM images of a 1-μm-thick cell section with projection angles between ±50° were collected, and the 3D volume structure was reconstructed using the simultaneous iterative reconstructive technique algorithm with the TomoJ plugin for ImageJ, which are both public domain software. Furthermore, the cross-sectional structure was obtained with the Volume Viewer plugin in ImageJ. Although the tilting angle is constrained and limits the resulting structural resolution, slicing the reconstructed volume generated the depth profile of the thick specimen with sufficient resolution to examine cellular uptake of Au nanoparticles, and the final position of these nanoparticles inside the cell was imaged.

  2. Scanning electron microscopy in characterizing seeds of some leguminous trees

    Science.gov (United States)

    Ghosh, Nabarun; Chatterjee, Amiyanghshu; Smith, Don W.

    2009-05-01

    SEM has greatly increased our knowledge of the microstructure of seeds. Mature seed coats are rather thick walled and stable in a vacuum: this allows quick preparation for SEM examination, without the need of complicated dehydration techniques. The low level of technical expenditure required, in combination with the high structural diversity exhibited and the intuitive ability to understand the "three dimensional", often aesthetically appealing micro-structures visualized, has turned seed-coat studies into a favorite tool of many taxonomists. We used dry mature seeds of 26 species of 4 Leguminous genera, Acacia, Albizia, Cassia and Dalbergia to standardize a procedure for identifying the seeds through SEM on the seed surface and seed sections. We cut transverse and longitudinal sections of the seeds and observed the sections from different regions of seeds: midseed, near the hilum and two distal ends. Light microscopy showed the color, texture, pleurograms, fissures and hilum at lower magnification. The anatomical study with SEM on the seed sections revealed the size, shape, and number of tiers and cellular organization of the epidermis, hypodermis, endosperm and internal structural details. We found the ornamentation pattern of the seeds including undulations, reticulations and rugae that were species specific. Species of Dalbergia (assamica, latifolia and sissoo), Albizia (odoratissima and procera), Acaia (arabica and catechu) and Cassia (glauca, siamia and spectabilis) are difficult to distinguish externally, but SEM studies provided enough characteristic features to distinguish from the other. This technique could be valuable in identifying seeds of important plant species for conservation and trading.

  3. Diverse Protocols for Correlative Super-Resolution Fluorescence Imaging and Electron Microscopy of Cells and Tissue

    Science.gov (United States)

    2016-05-25

    super - resolution fluorescence imaging and electron microscopy of cells and tissue Benjamin G. Kopek1, Maria G...have recently developed related approaches for super - resolution imaging within endogenous cellular environments using correlative light and electron...low as ~10 nm under ideal conditions), collectively dubbed “ super - resolution imaging ”5-10. A major super - resolution imaging modality is

  4. Integrated Raman and electron microscopy : correlative chemical specificity and nanoscale resolution

    NARCIS (Netherlands)

    Timmermans, Frank Jan

    2017-01-01

    This thesis describes the integration of a Raman microscope in a focused ion beam - scanning electron microscope (FIB-SEM). Raman micro-spectroscopy enables chemical specific characterization, while electron microscopy enables high resolution imaging. The Raman - SEM combination thus enables the

  5. 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.

  6. U-10Mo Sample Preparation and Examination using Optical and Scanning Electron Microscopy. Rev. 1

    International Nuclear Information System (INIS)

    Prabhakaran, Ramprashad; Joshi, Vineet V.; Rhodes, Mark A.; Schemer-Kohrn, Alan L.; Guzman, Anthony D.; Lavender, Curt A.

    2016-01-01

    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.

  7. Correlative Light and Electron Microscopy (CLEM) and its applications in infectious disease

    Science.gov (United States)

    2016-05-20

    Division, USAMRIID Abstract Correlative light and electron microscopy (CLEM) is an effective technique used to study biological samples. Signal...under the electron microscope (EM). Recent method developments provided breakthroughs creating an effective , direct, and accurate research...Examples include Lucifer yellow[67], Horseradish Peroxidase (HRP) conjugated IF antibodies [68] or co- expression with FP[69], boron-dipyrromethene (BODIPY

  8. Use of scanning electron microscopy and microanalysis to determine chloride content of concrete and raw materials.

    Science.gov (United States)

    2013-02-01

    Standard sample sets of cement and mortar formulations with known levels of Cl as well as concrete samples subject to Cl diffusion were all prepared for and analyzed with scanning electron microscopy (SEM) and electron microprobe (EPMA). Using x-ray ...

  9. 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.

  10. Proposals for the solution of the phase problem in electron microscopy

    International Nuclear Information System (INIS)

    Toorn, P. van.

    1979-01-01

    This thesis discusses the phase problem in electron microscopy, i.e. the determination of the unknown complex wave function in the image plane or in the exit pupil from the measured intensity distributions in both planes. The calculation of the wave function is the first problem to be solved for the determination of the object structure from electron micrographs. (Auth.)

  11. 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.

  12. Analysis of intermetallic particles in Mg-12 wt.%Zn binyry alloy using transmission electron microscopy

    Czech Academy of Sciences Publication Activity Database

    Němec, Martin; Gärtnerová, Viera; Klementová, Mariana; Jäger, Aleš

    2015-01-01

    Roč. 106, Aug (2015), s. 428-436 ISSN 1044-5803 R&D Projects: GA ČR GBP108/12/G043 Institutional support: RVO:68378271 Keywords : biomedical alloy s * heat treatment * microstructure * transmission electron microscopy * electron diffraction Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.383, year: 2015

  13. 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

  14. 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

  15. 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.

  16. Electron microscopy of fine-grained extraterrestrial materials

    International Nuclear Information System (INIS)

    Mackinnon, I.D.R.; McKay, D.S.; Isaacs, A.M.; Nace, G.

    1982-01-01

    Electron micrographs are shown of (a) Mighei C2 carbonaceous chondrite (variety of matrix phases present; micro-diffraction patterns of a region showing small, discrete intergrowths of planar serpentine and an ordered mixed-layer material; figures showing examples of textures which may be interpreted in terms of alteration processes, and inclusions); and (b) a typical cosmic dust particle collected by high-flying aircraft in the Earth's stratosphere. The composition and morphology of the samples are discussed and their significance. (U.K.)

  17. Remote punching of discs from radioactive samples for electron microscopy

    International Nuclear Information System (INIS)

    Rowe, J.; Madden, P.K.; Callen, V.M.

    1980-02-01

    A 'unidisc hand-operated press' has been modified for in-cave cutting of 3 mm diameter discs, destined for examination in the transmission electron microscope. No equivalent facility is available commercially. The modified punch is mechanically stable, compact in size for posting and easy to use since sample punching is controlled from a hand pump outside the cave. Discs may be cut from tested and untested strip tensile samples. The specially built sample locating jig may be interchanged to accept other sample geometries. (author)

  18. Characterization of catalysts by scanning transmission electron microscopy

    International Nuclear Information System (INIS)

    Targos, W.M.; Bradley, S.A.

    1989-01-01

    The dedicated scanning transmission electron microscope (STEM) is an integral tool for characterizing catalysts because of its unique ability to image and analyze nanosized volumes. This information is valuable in optimizing catalyst formulations and determining causes for reduced catalyst performance. For many commercial catalysts direct correlations between structural features of metal crystallites and catalytic performance are not attainable. When these instances occur, determination of elemental distribution may be the only information available. In this paper the authors discuss some of the techniques employed and limitations associated with characterizing commercial catalysts

  19. High-resolution electron microscopy of detonation nanodiamond

    International Nuclear Information System (INIS)

    Iakoubovskii, K; Mitsuishi, K; Furuya, K

    2008-01-01

    The structure of individual nanodiamond grains produced by the detonation of carbon-based explosives has been studied with a high-vacuum aberration-corrected electron microscope. Many grains show a well-resolved cubic diamond lattice with negligible contamination, thereby demonstrating that the non-diamond shell, universally observed on nanodiamond particles, could be intrinsic to the preparation process rather than to the nanosized diamond itself. The strength of the adhesion between the nanodiamond grains, and the possibility of their patterning with sub-nanometer precision, are also demonstrated

  20. High-resolution electron microscopy of detonation nanodiamond

    Energy Technology Data Exchange (ETDEWEB)

    Iakoubovskii, K; Mitsuishi, K [Quantum Dot Research Center, National Institute for Materials Science, 3-13 Sakura, Tsukuba 305-0005 (Japan); Furuya, K [High Voltage Microscopy Station, National Institute for Materials Science, 3-13 Sakura, Tsukuba 305-0005 (Japan)], E-mail: Iakoubovskii.Konstantin@nims.go.jp

    2008-04-16

    The structure of individual nanodiamond grains produced by the detonation of carbon-based explosives has been studied with a high-vacuum aberration-corrected electron microscope. Many grains show a well-resolved cubic diamond lattice with negligible contamination, thereby demonstrating that the non-diamond shell, universally observed on nanodiamond particles, could be intrinsic to the preparation process rather than to the nanosized diamond itself. The strength of the adhesion between the nanodiamond grains, and the possibility of their patterning with sub-nanometer precision, are also demonstrated.

  1. Analytic representation of electron central-axis depth dose data

    International Nuclear Information System (INIS)

    Jette, D.; Lanzl, L.H.; Rozenfeld, M.; Pagnamenta, A.

    1981-01-01

    We have examined a number of analytic representations of electron central-axis depth dose data current in the literature, testing them against sets of standard depth dose data. One of them, a two-parameter model of Shabason and Hendee, is recommended in situations in which good accuracy (approximately 2%) is desired, with the values of the parameters determined by an approximation formula which we have developed elsewhere. For higher accuracy, we have developed a polynomial model which gives, typically, a standard deviation of the fitting polynomial from the data points of 1%, and a maximum deviation of 2%. Fitting polynomials obtained with this method possess the property of having zero slope at the position of actual maximum dose, and generally a fifth-order polynomial (requiring four nonzero coefficients) provided the most acceptable fit. The four parameters involved are determined through inversion of a 4 x 4 matrix, and we have tabulated these four coefficients for the standard data sets. The polynomial model is designed for interpolation in the range between the 100% dose depth and the 10% dose depth, and another fitting curve of the same type can be adjoined to cover depths less than the 100% dose depth

  2. Quantitative electron microscopy and spectroscopy of MgB2 wires and tapes

    International Nuclear Information System (INIS)

    Birajdar, B; Peranio, N; Eibl, O

    2008-01-01

    In MgB 2 the correlation of microstructure with superconducting properties, in particular the critical current density, requires powerful analytical tools. Critical current densities and electrical resistivities of different MgB 2 superconductors differ by orders of magnitudes and the current limiting mechanisms have not been fully understood. Granularity of MgB 2 is one significant reason for reduced critical current densities and is introduced intrinsically by the anisotropy of B c2 but also extrinsically by the microstructure of the material. B c2 enhancement by doping is another important challenge for chemical analysis and, at present, doping levels are not well controlled on the sub-μm scale. In this paper the quantitative electron microscopy and spectroscopy methods essential for the microstructural analysis of MgB 2 are described. By quantitative electron microscopy and spectroscopy we mean a combined SEM and TEM analysis that covers various length scales from μm to nm. Contamination-free sample preparation, chemical mapping including B, and advanced chemical quantification using x-ray microanalysis were essential elements of the applied methodology. The methodology was applied to in situ and ex situ MgB 2 wires and tapes with and without SiC additives. Quantitative B analysis by EDX spectroscopy was applied quantitatively in the SEM and TEM, which is a major achievement. Although MgB 2 is a binary system, the thermodynamics of phase formation is complex, and the complexity is dramatically increased if additives like SiC are used. The small, sub-μm grain sizes of the matrix and secondary phases require TEM methods. However, granularity on the μm scale was also identified and underlines the importance of the combined SEM and TEM studies. Significant differences in the microstructure were observed for in situ and ex situ samples. This holds particularly if SiC was added and yielded Mg 2 Si for in situ samples annealed at 600-650 deg. C and Mg-Si-O phases

  3. Characterisation of archaeological glass mosaics by electron microscopy and X-ray microanalysis

    International Nuclear Information System (INIS)

    Roe, M; Plant, S; Henderson, J; Andreescu-Treadgold, I; Brown, P D

    2006-01-01

    The combined techniques of scanning electron microscopy, energy dispersive X-ray analysis, transmission electron microscopy (TEM) and selected area electron diffraction are used to characterise the microstructures of opaque coloured glass mosaics from a mediaeval church in Torcello, Italy. Comparison of MgO/K 2 O ratios allows distinction between mediaeval and modern glass artefacts to be made. TEM investigation of inclusions indicates that relict silica is responsible for the speckled appearance of an impure mediaeval glass artefact, whilst a fine scale dispersion of elemental Cu nanoparticles is considered responsible for the orange-red colouration of a modern glass artefact

  4. Electron microscopy approach for the visualization of the epithelial and endothelial glycocalyx.

    Science.gov (United States)

    Chevalier, L; Selim, J; Genty, D; Baste, J M; Piton, N; Boukhalfa, I; Hamzaoui, M; Pareige, P; Richard, V

    2017-06-01

    This study presents a methodological approach for the visualization of the glycocalyx by electron microscopy. The glycocalyx is a three dimensional network mainly composed of glycolipids, glycoproteins and proteoglycans associated with the plasma membrane. Since less than a decade, the epithelial and endothelial glycocalyx proved to play an important role in physiology and pathology, increasing its research interest especially in vascular functions. Therefore, visualization of the glycocalyx requires reliable techniques and its preservation remains challenging due to its fragile and dynamic organization, which is highly sensitive to the different process steps for electron microscopy sampling. In this study, chemical fixation was performed by perfusion as a good alternative to conventional fixation. Additional lanthanum nitrate in the fixative enhances staining of the glycocalyx in transmission electron microscopy bright field and improves its visualization by detecting the elastic scattered electrons, thus providing a chemical contrast. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  5. [Scanning electron microscopy and light microscopy under polarized light of a submandibular salivary gland calculus].

    Science.gov (United States)

    Traini, T; Murmura, G; Giammaria, G; Ciavarelli, L; Caputi, S

    2001-05-01

    The salivary calculus is an ancient pathologic condition, called sublingual stone by Hyppocrates. It is well-defined from a anatomo-pathologic, diagnostic and topographic viewpoint, though some pathogenesis-related doubts still exist. This work aims at relating the micro-morpho-structural aspect of a salivary calculus of remarkable dimensions with the current calculogenetic hypotheses. A 1.1 g salivary calculus removed from the initial section of Wrthon s duct in the right-hand submandibular gland of a 42 year old male has been studied. Following the fixation in 4% buffered formalin and the inclusion in resin, it was serially sectioned in 15-20 micron slices. Some sections were coloured with toluidine blue O and acid fuchsin. The exeresis of the calculus was carried out intraorally, with marsupialization under local anesthesia. The analysis was performed using a SEM with backscattered electrons and a polarised and transmitted light microscope. The investigations have outlined the presence of various organic cores and a concentric, stratiform architecture interrupted by radial elements. The formation of this calculus may be due to mixed secondary lithiasis resulting from the formation of colloids and crystalloids.

  6. Evolutionary developments in x ray and electron energy loss microanalysis instrumentation for the analytical electron microscope

    Science.gov (United States)

    Zaluzec, Nester J.

    Developments in instrumentation for both X ray Dispersive and Electron Energy Loss Spectroscopy (XEDS/EELS) over the last ten years have given the experimentalist a greatly enhanced set of analytical tools for characterization. Microanalysts have waited for nearly two decades now in the hope of getting a true analytical microscope and the development of 300 to 400 kV instruments should have allowed us to attain this goal. Unfortunately, this has not generally been the case. While there have been some major improvements in the techniques, there has also been some devolution in the modern AEM (Analytical Electron Microscope). In XEDS, the majority of today's instruments are still plagued by the hole count effect, which was first described in detail over fifteen years ago. The magnitude of this problem can still reach the 20 percent level for medium atomic number species in a conventional off-the-shelf intermediate voltage AEM. This is an absurd situation and the manufacturers should be severely criticized. Part of the blame, however, also rests on the AEM community for not having come up with a universally agreed upon standard test procedure. Fortunately, such a test procedure is in the early stages of refinement. The proposed test specimen consists of an evaporated Cr film approx. 500 to 1000A thick supported upon a 3mm diameter Molybdenum 200 micron aperture.

  7. Transmission electron microscopy characterization of photocatalysts for water splitting

    DEFF Research Database (Denmark)

    Cavalca, Filippo; Laursen, Anders Bo; Dahl, Søren

    , it is necessary to understand the fundamentals of their reaction mechanisms, chemical behavior, structure and morphology before, during and after reaction using in situ investigations. Here, we focus on the in situ characterization of photocatalysts [1] in an environmental transmission electron microscope (ETEM......) [2]. Such fundamental insight can be used for further material optimization with respect to performance and stability [3]. In this work, we combine conventional TEM analysis of photocatalysts with environmental TEM (ETEM) and photoactivation using light. A novel type of TEM specimen holder...... that enables in situ illumination is developed to study light-induced phenomena in photoactive materials at the nanoscale under working conditions. Our experiments are aimed at exposing a specimen to light and detecting resulting microstructural and chemical changes using in situ TEM techniques...

  8. Conditioning of mealybug (Hemiptera: Pseudococcidae) by Scanning Electron Microscopy

    International Nuclear Information System (INIS)

    Palma-Jimenez, Melissa; Blanco-Meneses, Monica

    2015-01-01

    The cleaning and correct observation of the mealybug specimens was determined by the conditioning methodology. The research was done in the Laboratorio del Centro de Investigacion en Estructuras Microscopicas (CIEMIC) of the Universidad de Costa Rica during the year 2012. A gradual improvement for the observation of the ultrastructures through the Scanning Electron Microscope was evidenced by the implementation of four types of methodologies. Each process was described in detail. The incorporation of 10% xylene (in some cases have been viable using ethanol at 95-100% ) was allowed to remove the wax from the body of the insect, to avoid this the collapse and to observe specific ultrastructures of the individual, they were the best results. The methodology used has reduced the time and costs in future taxonomic research of mealybug. (author) [es

  9. 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.

  10. Sample preparation and electron microscopy of hydrocracking catalysts

    Science.gov (United States)

    Husain, S.; McComb, D. W.; Perkins, J. M.; Haswell, R.

    2008-08-01

    This work focuses on the preparation of zeolite and alumina hydrocracking catalysts for investigation by electron energy-loss spectroscopy (EELS). EELS can potentially give new insights into the location and structure of coke which can result in catalyst deactivation. Three sample preparation techniques have been used - microtoming, focussed ion beam milling (LIB) and conventional ion beam milling. Crushing and grinding the catalyst pellets has been discounted as a preparation technique as the spatial relationship between the coke and the catalyst is lost using this method. Microtomed sections show some mechanical damage while sections milled in a single beam LIB microscope show gallium decoration in pores and were too thick for EELS. Conventional ion beam milling has proved to be most successful as it results in extensive thin regions and maintains the spatial distribution of the zeolite and alumina phases.

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

    DEFF Research Database (Denmark)

    Horsewell, Andy

    , comprise a unique assembly of outstanding instruments for research, teaching and innovation. In order to operate at peak performance, such instruments place extreme demands on the stability of the environment around them. All of the following factors must be minimized through careful building design...... and construction: vibrations transmitted through the ground and acoustically; variations in room temperature and rates of airflow; variations in microscope cooling; magnetic fields. At the same time, we have been keen to design a pleasant, creative and dynamic working environment for the study of nanostructures...... 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...

  12. Advanced scanning transmission stereo electron microscopy of structural and functional engineering materials

    International Nuclear Information System (INIS)

    Agudo Jácome, L.; Eggeler, G.; Dlouhý, A.

    2012-01-01

    Stereo transmission electron microscopy (TEM) provides a 3D impression of the microstructure in a thin TEM foil. It allows to perform depth and TEM foil thickness measurements and to decide whether a microstructural feature lies inside of a thin foil or on its surface. It allows appreciating the true three-dimensional nature of dislocation configurations. In the present study we first review some basic elements of classical stereo TEM. We then show how the method can be extended by working in the scanning transmission electron microscope (STEM) mode of a modern analytical 200 kV TEM equipped with a field emission gun (FEG TEM) and a high angle annular dark field (HAADF) detector. We combine two micrographs of a stereo pair into one anaglyph. When viewed with special colored glasses the anaglyph provides a direct and realistic 3D impression of the microstructure. Three examples are provided which demonstrate the potential of this extended stereo TEM technique: a single crystal Ni-base superalloy, a 9% Chromium tempered martensite ferritic steel and a NiTi shape memory alloy. We consider the effect of camera length, show how foil thicknesses can be measured, and discuss the depth of focus and surface effects. -- Highlights: ► The advanced STEM/HAADF diffraction contrast is extended to 3D stereo-imaging. ► The advantages of the new technique over stereo-imaging in CTEM are demonstrated. ► The new method allows foil thickness measurements in a broad range of conditions. ► We show that features associated with ion milling surface damage can be beneficial for appreciating 3D features of the microstructure.

  13. Dopant profiling based on scanning electron and helium ion microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Chee, Augustus K.W., E-mail: kwac2@cam.ac.uk [Centre for Advanced Photonics and Electronics, Electrical Engineering Division, Department of Engineering, University of Cambridge, 9 JJ Thomson Avenue, Cambridge CB3 0FA (United Kingdom); Boden, Stuart A. [University of Southampton, Electronics and Computer Science, Highfield, Southampton SO17 1BJ (United Kingdom)

    2016-02-15

    In this paper, we evaluate and compare doping contrast generated inside the scanning electron microscope (SEM) and scanning helium ion microscope (SHIM). Specialised energy-filtering techniques are often required to produce strong doping contrast to map donor distributions using the secondary electron (SE) signal in the SEM. However, strong doping contrast can be obtained from n-type regions in the SHIM, even without energy-filtering. This SHIM technique is more sensitive than the SEM to donor density changes above its sensitivity threshold, i.e. of the order of 10{sup 16} or 10{sup 17} donors cm{sup −3} respectively on specimens with or without a p–n junction; its sensitivity limit is well above 2×10{sup 17} acceptors cm{sup −3} on specimens with or without a p–n junction. Good correlation is found between the widths and slopes of experimentally measured doping contrast profiles of thin p-layers and the calculated widths and slopes of the potential energy distributions across these layers, at a depth of 1 to 3 nm and 5 to 10 nm below the surface in the SHIM and the SEM respectively. This is consistent with the mean escape depth of SEs in silicon being about 1.8 nm and 7 nm in the SHIM and SEM respectively, and we conclude that short escape depth, low energy SE signals are most suitable for donor profiling. - Highlights: • Strong doping contrast from n-type regions in the SHIM without energy-filtering. • Sensitivity limits are established of the SHIM and SEM techniques. • We discuss the impact of SHIM imaging conditions on quantitative dopant profiling. • Doping contrast stems from different surface layer thicknesses in the SHIM and SEM.

  14. 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.

  15. 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

  16. EM∩IM: software for relating ion mobility mass spectrometry and electron microscopy data.

    Science.gov (United States)

    Degiacomi, Matteo T; Benesch, Justin L P

    2016-01-07

    We present EM∩IM, software that allows the calculation of collision cross-sections from electron density maps obtained for example by means of transmission electron microscopy. This allows the assessment of structures other than those described by atomic coordinates with ion mobility mass spectrometry data, and provides a new means for contouring and validating electron density maps. EM∩IM thereby facilitates the use of data obtained in the gas phase within structural biology studies employing diverse experimental methodologies.

  17. Very Low Energy Scanning Electron Microscopy of Free-Standing Ultrathin Films

    Czech Academy of Sciences Publication Activity Database

    Müllerová, Ilona; Hovorka, Miloš; Hanzlíková, Renáta; Frank, Luděk

    2010-01-01

    Roč. 51, č. 2 (2010), s. 265-270 ISSN 1345-9678 R&D Projects: GA AV ČR IAA100650902 Institutional research plan: CEZ:AV0Z20650511 Keywords : low energy scanning electron microscopy * thin foils * transmission of very slow electrons Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 0.779, year: 2010 http://www.jim.or.jp/journal/e/51/02/265.html

  18. 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.

    2014-11-01

    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.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

  19. Concept and design of a beam blanker with integrated photoconductive switch for ultrafast electron microscopy

    NARCIS (Netherlands)

    Weppelman, I.G.C.; Moerland, R.J.; Hoogenboom, J.P.; Kruit, P.

    2018-01-01

    We present a new method to create ultrashort electron pulses by integrating a photoconductive switch with an electrostatic deflector. This paper discusses the feasibility of such a system by analytical and numerical calculations. We argue that ultrafast electron pulses can be achieved for

  20. Imaging of phase change materials below a capping layer using correlative infrared near-field microscopy and electron microscopy

    Science.gov (United States)

    Lewin, M.; Hauer, B.; Bornhöfft, M.; Jung, L.; Benke, J.; Michel, A.-K. U.; Mayer, J.; Wuttig, M.; Taubner, T.

    2015-10-01

    Phase Change Materials (PCM) show two stable states in the solid phase with significantly different optical and electronic properties. They can be switched reversibly between those two states and are promising candidates for future non-volatile memory applications. The development of phase change devices demands characterization tools, yielding information about the switching process at high spatial resolution. Scattering-type Scanning Near-field Optical Microscopy (s-SNOM) allows for spectroscopic analyses of the different optical properties of the PCMs on the nm-scale. By correlating the optical s-SNOM images with transmission electron microscopy images of the same sample, we unambiguously demonstrate the correlation of the infrared optical contrast with the structural state of the phase change material. The investigated sample consists of sandwiched amorphous and crystalline regions of Ag 4 In 3 Sb 67 Te 26 below a 100 nm thick ( ZnS ) 80 - ( SiO2 ) 20 capping layer. Our results demonstrate the sensitivity of s-SNOM to small dielectric near-field contrasts even below a comparably thick capping layer ( 100 nm ).

  1. Electron Microscopy and Image Analysis for Selected Materials

    Science.gov (United States)

    Williams, George

    1999-01-01

    This particular project was completed in collaboration with the metallurgical diagnostics facility. The objective of this research had four major components. First, we required training in the operation of the environmental scanning electron microscope (ESEM) for imaging of selected materials including biological specimens. The types of materials range from cyanobacteria and diatoms to cloth, metals, sand, composites and other materials. Second, to obtain training in surface elemental analysis technology using energy dispersive x-ray (EDX) analysis, and in the preparation of x-ray maps of these same materials. Third, to provide training for the staff of the metallurgical diagnostics and failure analysis team in the area of image processing and image analysis technology using NIH Image software. Finally, we were to assist in the sample preparation, observing, imaging, and elemental analysis for Mr. Richard Hoover, one of NASA MSFC's solar physicists and Marshall's principal scientist for the agency-wide virtual Astrobiology Institute. These materials have been collected from various places around the world including the Fox Tunnel in Alaska, Siberia, Antarctica, ice core samples from near Lake Vostoc, thermal vents in the ocean floor, hot springs and many others. We were successful in our efforts to obtain high quality, high resolution images of various materials including selected biological ones. Surface analyses (EDX) and x-ray maps were easily prepared with this technology. We also discovered and used some applications for NIH Image software in the metallurgical diagnostics facility.

  2. Scanning electron microscopy of corrosion casting in medicine.

    Science.gov (United States)

    Konerding, M A

    1991-09-01

    The aims of this review are: 1. to provide a bibliography of the publications that have used the corrosion casting technique; 2. to describe the advantages and limitations of the methodology; 3. to illustrate possible applications in the field of medicine, and 4. to highlight the significance of this method in the teaching of medical students. Thus, this paper is primarily focused on the scanning electron microscopical examination of vascular corrosion casts. The unsurpassed three-dimensionality of the corrosion casting technique compared to any other means stands out in particular. This can be especially useful when complex vascular-anatomical relationships are present. This applies not only to the portrayal of the modes of branching and varying vascular densities but also to regulatory arrangements, such as sphincters and arteriovenous anastomoses. Between 1966 and 1990, a total of 549 publications were found in the Medline literature data bank, containing the key words "corrosion casting", "microvascular cast", or "vascular cast" (as of August, 1990). Of those publications, most dealt with applications to experimental animals. By contrast, only 142 reports were mainly or partially concerned with human investigational material. The normal vascular system of nearly all organs, insofar as this is of direct medical relevance, has been largely resolved. In our opinion, one of the most important potential applications of the corrosion casting technique lies in the investigation of gastrointestinal, renal or hepatic ailments, which coincide with the reconstruction or rarefication of the vascular bed, e.g., in ulcers, ileitis terminalis, colitis ulcerosa, cirrhosis or glomerulonephritis.

  3. Automated rapid particle investigation using scanning electron microscopy

    Science.gov (United States)

    Wilkins, Jerod Laurence

    The chemical composition of fly ash particles has been known to vary significantly depending on a number of factors. Current bulk methods of investigation including X-Ray Fluorescence and X-Ray Diffraction are thought to be inadequate in determining the performance of fly ash in concrete. It is the goal of this research to develop a method of Automated Rapid Particle Investigation that will not look at fly ash as a bulk material but as individual particles. By examining each particle individually scientists and engineers will have the ability to study the variation in chemical composition by comparing the chemistry present in each particle. The method of investigation developed by this research provides a practical technique that will allow the automated chemical analysis of hundreds, or even thousands, of fly ash particles in a matter of minutes upon completion of sample preparation and automated scanning electron microscope (ASEM) scanning. This research does not examine the significance of the chemical compounds discovered; rather, only the investigation methodology is discussed. Further research will be done to examine the importance of the chemistry discovered with this automated rapid particle investigation technique.

  4. Scanning and Transmission Electron Microscopy of High Temperature Materials

    Science.gov (United States)

    1994-01-01

    Software and hardware updates to further extend the capability of the electron microscope were carried out. A range of materials such as intermetallics, metal-matrix composites, ceramic-matrix composites, ceramics and intermetallic compounds, based on refractory elements were examined under this research. Crystal structure, size, shape and volume fraction distribution of various phases which constitute the microstructures were examined. Deformed materials were studied to understand the effect of interfacial microstructure on the deformation and fracture behavior of these materials. Specimens tested for a range of mechanical property requirements, such as stress rupture, creep, low cycle fatigue, high cycle fatigue, thermomechanical fatigue, etc. were examined. Microstructural and microchemical stability of these materials exposed to simulated operating environments were investigated. The EOIM Shuttle post-flight samples were also examined to understand the influence of low gravity processing on microstructure. In addition, fractographic analyses of Nb-Zr-W, titanium aluminide, molybdenum silicide and silicon carbide samples were carried out. Extensive characterization of sapphire fibers in the fiber-reinforced composites made by powder cloth processing was made. Finally, pressure infiltration casting of metal-matrix composites was carried out.

  5. Transmission Electron Microscopy of Bombyx Mori Silk Fibers

    Science.gov (United States)

    Shen, Y.; Martin, D. C.

    1997-03-01

    The microstructure of B. Mori silk fibers before and after degumming was examined by TEM, selected area electron diffraction (SAED), WAXS and low voltage SEM. SEM micrographs of the neat cocoon revealed a network of pairs of twisting filaments. After degumming, there were only individual filaments showing a surface texture consistent with an oriented fibrillar structure in the fiber interior. WAXS patterns confirmed the oriented beta-sheet crystal structure common to silkworm and spider silks. Low dose SAED results were fully consistent with the WAXS data, and revealed that the crystallographic texture did not vary significantly across the fiber diameter. TEM observations of microtomed fiber cross sections indicated a somewhat irregular shape, and also revealed a 0.5-2 micron sericin coating which was removed by the degumming process. TEM observations of the degummed silk fiber showed banded features with a characteristic spacing of nominally 600 nm along the fiber axis. These bands were oriented in a roughly parabolic or V-shape pointing along one axis within a given fiber. We hypothesize that this orientation is induced by the extrusion during the spinning process. Equatorial DF images revealed that axial and lateral sizes of the β-sheet crystallites in silk fibroin ranged from 20 to 170 nm and from 1 to 24 nm, respectively. Crazes developed in the degummed silk fiber parallel to the fiber direction. The formation of these crazes suggests that there are significant lateral interactions between fibrils in silk fibers.

  6. 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.

  7. UROX 2.0: an interactive tool for fitting atomic models into electron-microscopy reconstructions

    International Nuclear Information System (INIS)

    Siebert, Xavier; Navaza, Jorge

    2009-01-01

    UROX is software designed for the interactive fitting of atomic models into electron-microscopy reconstructions. The main features of the software are presented, along with a few examples. Electron microscopy of a macromolecular structure can lead to three-dimensional reconstructions with resolutions that are typically in the 30–10 Å range and sometimes even beyond 10 Å. 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/

  8. Description of a neural sheath tumor of the trigeminal nerve: immunohistochemical and electron microscopy study

    OpenAIRE

    Khademi, Bijan; Owji, Seied Mohammad; Khosh, Khadije Jamshidi; Mohammadianpanah, Mohammad; Gandomi, Behrooz

    2006-01-01

    CONTEXT: Malignant neural sheath tumors of the trigeminal nerve affecting the nasal cavity and the paranasal sinuses are extremely rare. With conventional optical microscopy, their identification is difficult, and it is necessary to confirm them by means of electron microscopy and immunohistochemical techniques. CASE REPORT: The patient was a 41-year-old woman with a ten-month progressive history of pain followed by painful edema in the left facial region, and with symptoms of bleeding, secre...

  9. Electron sputtering in the analytical electron microscope: Calculations and experimental data

    International Nuclear Information System (INIS)

    Zaluzec, N.J.; Mansfield, J.F.

    1987-03-01

    The environment of the electron microscope is particularly severe when one considers the energy deposited in a specimen during typical experimental conditions. Conventional imaging experiments tend to employ electron current densities ranging from ∼0.1 to 1 A/cm 2 while during microanalysis conditions probe current densities can range from 10 to values as high as 10 5 A/cm 2 . At 100 kV this corresponds to power densities from 100 Kilowatts/cm 2 to 10 4 Megawatts/cm 2 . These energy deposition rates can result in electron irradiation damage which can substantially alter the structure and composition of a specimen through either ionization damage in organics or by displacement damage in inorganics and/or combinations thereof. For the most part materials scientists operating an analytical electron microscope (AEM) in the 100 to 200 kV regime studying metallic and/or ceramic specimens have been spared the need to consider either of these effects as their specimens have tended to be sufficiently resilient. However, the advent of the new medium voltage microscopes operating in the 300 to 400 kV regime with high brightness guns and clean or ultrahigh vacuum systems has necessitated a reevaluation of the effects of higher voltage operation in light of the destructive nature of the electron beam particularly under microanalysis conditions

  10. 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.

  11. Modelling high-resolution electron microscopy based on core-loss spectroscopy

    International Nuclear Information System (INIS)

    Allen, L.J.; Findlay, S.D.; Oxley, M.P.; Witte, C.; Zaluzec, N.J.

    2006-01-01

    There are a number of factors affecting the formation of images based on core-loss spectroscopy in high-resolution electron microscopy. We demonstrate unambiguously the need to use a full nonlocal description of the effective core-loss interaction for experimental results obtained from high angular resolution electron channelling electron spectroscopy. The implications of this model are investigated for atomic resolution scanning transmission electron microscopy. Simulations are used to demonstrate that core-loss spectroscopy images formed using fine probes proposed for future microscopes can result in images that do not correspond visually with the structure that has led to their formation. In this context, we also examine the effect of varying detector geometries. The importance of the contribution to core-loss spectroscopy images by dechannelled or diffusely scattered electrons is reiterated here

  12. 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.

  13. Correlation of live-cell imaging with volume scanning electron microscopy.

    Science.gov (United States)

    Lucas, Miriam S; Günthert, Maja; Bittermann, Anne Greet; de Marco, Alex; Wepf, Roger

    2017-01-01

    Live-cell imaging is one of the most widely applied methods in live science. Here we describe two setups for live-cell imaging, which can easily be combined with volume SEM for correlative studies. The first procedure applies cell culture dishes with a gridded glass support, which can be used for any light microscopy modality. The second approach is a flow-chamber setup based on Ibidi μ-slides. Both live-cell imaging strategies can be followed up with serial blockface- or focused ion beam-scanning electron microscopy. Two types of resin embedding after heavy metal staining and dehydration are presented making best use of the particular advantages of each imaging modality: classical en-bloc embedding and thin-layer plastification. The latter can be used only for focused ion beam-scanning electron microscopy, but is advantageous for studying cell-interactions with specific substrates, or when the substrate cannot be removed. En-bloc embedding has diverse applications and can be applied for both described volume scanning electron microscopy techniques. Finally, strategies for relocating the cell of interest are discussed for both embedding approaches and in respect to the applied light and scanning electron microscopy methods. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. Characterization of multilayer nitride coatings by electron microscopy and modulus mapping

    International Nuclear Information System (INIS)

    Pemmasani, Sai Pramod; Rajulapati, Koteswararao V.; Ramakrishna, M.; Valleti, Krishna; Gundakaram, Ravi C.; Joshi, Shrikant V.

    2013-01-01

    This paper discusses multi-scale characterization of physical vapour deposited multilayer nitride coatings using a combination of electron microscopy and modulus mapping. Multilayer coatings with a triple layer structure based on TiAlN and nanocomposite nitrides with a nano-multilayered architecture were deposited by Cathodic arc deposition and detailed microstructural studies were carried out employing Energy Dispersive Spectroscopy, Electron Backscattered Diffraction, Focused Ion Beam and Cross sectional Transmission Electron Microscopy in order to identify the different phases and to study microstructural features of the various layers formed as a result of the deposition process. Modulus mapping was also performed to study the effect of varying composition on the moduli of the nano-multilayers within the triple layer coating by using a Scanning Probe Microscopy based technique. To the best of our knowledge, this is the first attempt on modulus mapping of cathodic arc deposited nitride multilayer coatings. This work demonstrates the application of Scanning Probe Microscopy based modulus mapping and electron microscopy for the study of coating properties and their relation to composition and microstructure. - Highlights: • Microstructure of a triple layer nitride coating studied at multiple length scales. • Phases identified by EDS, EBSD and SAED (TEM). • Nanolayered, nanocomposite structure of the coating studied using FIB and TEM. • Modulus mapping identified moduli variation even in a nani-multilayer architecture

  15. Cryogenic-temperature electron microscopy direct imaging of carbon nanotubes and graphene solutions in superacids.

    Science.gov (United States)

    Kleinerman, O; Parra-Vasquez, A Nicholas G; Green, M J; Behabtu, N; Schmidt, J; Kesselman, E; Young, C C; Cohen, Y; Pasquali, M; Talmon, Y

    2015-07-01

    Cryogenic electron microscopy (cryo-EM) is a powerful tool for imaging liquid and semiliquid systems. While cryogenic transmission electron microscopy (cryo-TEM) is a standard technique in many fields, cryogenic scanning electron microscopy (cryo-SEM) is still not that widely used and is far less developed. The vast majority of systems under investigation by cryo-EM involve either water or organic components. In this paper, we introduce the use of novel cryo-TEM and cryo-SEM specimen preparation and imaging methodologies, suitable for highly acidic and very reactive systems. Both preserve the native nanostructure in the system, while not harming the expensive equipment or the user. We present examples of direct imaging of single-walled, multiwalled carbon nanotubes and graphene, dissolved in chlorosulfonic acid and oleum. Moreover, we demonstrate the ability of these new cryo-TEM and cryo-SEM methodologies to follow phase transitions in carbon nanotube (CNT)/superacid systems, starting from dilute solutions up to the concentrated nematic liquid-crystalline CNT phases, used as the 'dope' for all-carbon-fibre spinning. Originally developed for direct imaging of CNTs and graphene dissolution and self-assembly in superacids, these methodologies can be implemented for a variety of highly acidic systems, paving a way for a new field of nonaqueous cryogenic electron microscopy. © 2015 The Authors Journal of Microscopy © 2015 Royal Microscopical Society.

  16. 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

  17. 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}.

  18. A diagnostic mystery solved by electron microscopy: a case of an "atypical" lymphoproliferative disorder.

    Science.gov (United States)

    Lee, Sophie; Graham, Linda M; Chan, George; Ruskova, Anna

    2012-10-01

    An elderly woman with a previous diagnosis of atypical chronic lymphocytic leukemia (CLL) was noted to have a strikingly abnormal blood film, with the lymphocytes displaying numerous large cytoplasmic granules. This appearance had not been described before in the literature to the best of the authors' knowledge. After a series of investigations, electron microscopy was eventually performed, which demonstrated that the abnormal granules were composed of immunoglobulin crystals. The immunofixation study confirmed that they were monoclonal IgM paraprotein. These results led to a change of diagnosis to lymphoplasmacytic lymphoma. This report illustrates how electron microscopy can be used as a valuable additional diagnostic tool in difficult cases.

  19. Studies on the transformation of fibrinogen to fibrin. Radiation effects. Observation by electron microscopy

    International Nuclear Information System (INIS)

    Marguerie de Rotrou, G.; Hollard, D.; Suscillon, M.; Cuong, M.; Vitry, F. de

    1968-01-01

    The authors used electron microscopy, thrombo-dynamo-graphy and spectrophotometry, to study the damage caused by X rays on the fibrinogen molecule and fibrin-formation process. This process is highly disturbed by increasing doses of irradiation from 0 to 3.10 5 roentgen. Electron microscopy observation shows interesting data on the structure of the plug, formed by irradiated fibrinogen solution. This study also lead the authors to propose a new model of the fibrinogen molecule and a schema explaining observed striations and granular appearance of the fibrin fibers surface. (authors) [fr

  20. Parainfluenza virus type 5 (PIV-5) morphology revealed by cryo-electron microscopy.

    Science.gov (United States)

    Terrier, Olivier; Rolland, Jean-Paul; Rosa-Calatrava, Manuel; Lina, Bruno; Thomas, Daniel; Moules, Vincent

    2009-06-01

    The knowledge of parainfluenza type 5 (PIV-5) virion morphology is essentially based on the observation of negatively stained preparations in conventional transmission electron microscopy (CTEM). In this study, the ultrastructure of frozen-hydrated intact PIV-5 was examined by cryo-electron microscopy (cryo-EM). Cryo-EM revealed a majority of spherical virions (70%), with a lower pleiomorphy than originally observed in CTEM. Phospholipid bilayer thickness, spike length and glycoprotein spikes density were measured. About 2000 glycoprotein spikes were present in an average-sized spherical virion. Altogether, these data depict a more precise view of PIV-5 morphology.

  1. 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.

  2. Low-voltage electron microscopy of polymer and organic molecular thin films

    International Nuclear Information System (INIS)

    Drummy, L.F.; Yang Junyan; Martin, D.C.

    2004-01-01

    We have demonstrated the capabilities of a novel low-voltage electron microscope (LVEM) for imaging polymer and organic molecular thin films. The LVEM can operate in transmission electron microscopy, scanning transmission electron microscopy, scanning electron microscopy, and electron diffraction modes. The microscope operates at a nominal accelerating voltage of 5 kV and fits on a tabletop. A detailed discussion of the electron-sample interaction processes is presented, and the mean free path for total electron scattering was calculated to be 15 nm for organic samples at 5 kV. The total end point dose for the destruction of crystallinity at 5 kV was estimated at 5x10 -4 and 3.5x10 -2 C/cm 2 for polyethylene and pentacene, respectively. These values are significantly lower than those measured at voltages greater than 100 kV. A defocus series of colloidal gold particles allowed us to estimate the experimental contrast transfer function of the microscope. Images taken of several organic materials have shown high contrast for low atomic number elements and a resolution of 2.5 nm. The materials studied here include thin films of the organic semiconductor pentacene, triblock copolymer films, single-molecule dendrimers, electrospun polymer fibers and gold nanoparticles

  3. Quantitative characterization of the composition, thickness and orientation of thin films in the analytical electron microscope

    International Nuclear Information System (INIS)

    Williams, D.B.; Watanabe, M.; Papworth, A.J.; Li, J.C.

    2003-01-01

    Compositional variations in thin films can introduce lattice-parameter changes and thus create stresses, in addition to the more usual stresses introduced by substrate-film mismatch, differential thermal expansion, etc. Analytical electron microscopy comprising X-ray energy-dispersive spectrometry within a probe-forming field-emission gun scanning transmission electron microscope (STEM) is one of the most powerful methods of composition measurement on the nanometer scale, essential for thin-film analysis. Recently, with the development of improved X-ray collection efficiencies and quantitative computation methods it has proved possible to map out composition variations in thin films with a spatial resolution approaching 1-2 nm. Because the absorption of X-rays is dependent on the film thickness, concurrent composition and film thickness determination is another advantage of X-ray microanalysis, thus correlating thickness and composition variations, either of which may contribute to stresses in the film. Specific phenomena such as segregation to interfaces and boundaries in the film are ideally suited to analysis by X-ray mapping. This approach also permits multiple boundaries to be examined, giving some statistical certainty to the analysis particularly in nano-crystalline materials with grain sizes greater than the film thickness. Boundary segregation is strongly affected by crystallographic misorientation and it is now possible to map out the orientation between many different grains in the (S)TEM

  4. Electron microscopy: An introduction (with a special section on convergent-beam diffraction)

    International Nuclear Information System (INIS)

    Eades, J.A.

    1980-01-01

    Electron microscopy is of great importance in materials science, but the term covers a wide range of instruments and techniques, many of great complexity. The article considers the reasons for the importance of electron microscopes, some aspects of their construction and then considers in turn the scanning electron microscope and the transmission electron microscope, discussing briefly the image formation and applications of each type. A final section is dedicated to a more detailed discussion of a particular technique of rapidly growing importance: convergent-beam microscopy. Convergent-beam diffraction can supply information on lattice parameter, symmetry and crystal structure; it can be used to identify the phases present in a finely dispersed mixture. Moreover, all this can be carried out with accuracy, which is unprecedented for samples which are so small. (author)

  5. Growth and intercalation of graphene on silicon carbide studied by low-energy electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Speck, Florian; Ostler, Markus; Wanke, Martina; Seyller, Thomas [Universitaet Erlangen-Nuernberg, Lehrstuhl fuer Technische Physik, Erlangen (Germany); Technische Universitaet Chemnitz, Institut fuer Physik (Germany); Besendoerfer, Sven [Universitaet Erlangen-Nuernberg, Lehrstuhl fuer Technische Physik, Erlangen (Germany); Krone, Julia [Technische Universitaet Chemnitz, Institut fuer Physik (Germany)

    2017-11-15

    Based on its electronic, structural, chemical, and mechanical properties, many potential applications have been proposed for graphene. In order to realize these visions, graphene has to be synthesized, grown, or exfoliated with properties that are determined by the targeted application. Growth of so-called epitaxial graphene on silicon carbide by sublimation of silicon in an argon atmosphere is one particular method that could potentially lead to electronic applications. In this contribution we summarize our recent work on different aspects of epitaxial graphene growth and interface manipulation by intercalation, which was performed by a combination of low-energy electron microscopy, low-energy electron diffraction, atomic force microscopy and photoelectron spectroscopy. (copyright 2017 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  6. Topographic and electronic contrast of the graphene moir´e on Ir(111) probed by scanning tunneling microscopy and noncontact atomic force microscopy

    NARCIS (Netherlands)

    Sun, Z.; Hämäläinen, K.; Sainio, K.; Lahtinen, J.; Vanmaekelbergh, D.A.M.; Liljeroth, P.

    2011-01-01

    Epitaxial graphene grown on transition-metal surfaces typically exhibits a moir´e pattern due to the lattice mismatch between graphene and the underlying metal surface. We use both scanning tunneling microscopy (STM) and atomic force microscopy (AFM) to probe the electronic and topographic contrast

  7. Chemical mapping and quantification at the atomic scale by scanning transmission electron microscopy.

    Science.gov (United States)

    Chu, Ming-Wen; Chen, Cheng Hsuan

    2013-06-25

    With innovative modern material-growth methods, a broad spectrum of fascinating materials with reduced dimensions-ranging from single-atom catalysts, nanoplasmonic and nanophotonic materials to two-dimensional heterostructural interfaces-is continually emerging and extending the new frontiers of materials research. A persistent central challenge in this grand scientific context has been the detailed characterization of the individual objects in these materials with the highest spatial resolution, a problem prompting the need for experimental techniques that integrate both microscopic and spectroscopic capabilities. To date, several representative microscopy-spectroscopy combinations have become available, such as scanning tunneling microscopy, tip-enhanced scanning optical microscopy, atom probe tomography, scanning transmission X-ray microscopy, and scanning transmission electron microscopy (STEM). Among these tools, STEM boasts unique chemical and electronic sensitivity at unparalleled resolution. In this Perspective, we elucidate the advances in STEM and chemical mapping applications at the atomic scale by energy-dispersive X-ray spectroscopy and electron energy loss spectroscopy with a focus on the ultimate challenge of chemical quantification with atomic accuracy.

  8. Scanning Electron Microscopy of Nonconductive Specimens at Critical Energies in a Cathode Lens System

    Czech Academy of Sciences Publication Activity Database

    Frank, Luděk; Zadražil, Martin; Müllerová, Ilona

    2001-01-01

    Roč. 23, č. 1 (2001), s. 36-50 ISSN 0161-0457 R&D Projects: GA ČR GA202/96/0961; GA ČR GA202/99/0008 Institutional research plan: CEZ:AV0Z2065902 Keywords : scanning electron microscopy * specimen charging * nonconductive specimens Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 0.389, year: 2001

  9. 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/.

  10. Surface sensitivity effects with local probe scanning Auger-scanning electron microscopy

    NARCIS (Netherlands)

    Van Agterveld, DTL; Palasantzas, G; De Hosson, JTM; Bentley, J; Allen, C; Dahmen, U; Petrov,

    2001-01-01

    Ultra-high-vacuum segregation studies on in-situ fractured Cu-Sb alloys were performed in terms of nanometer scale scanning Auger/Electron microscopy. S contamination leads to the formation Of Cu2S precipitates which, upon removal due to fracture, expose pits with morphology that depends on the

  11. Proposals for the solution of the phase problem in electron microscopy

    NARCIS (Netherlands)

    Toorn, Peter van

    1979-01-01

    In this thesis we discuss the phase problem in electron microscopy, i.e. the determination of the unknown complex wave function in the image plane or in the exit pupil from the measured intensity distributions in both planes. The calculation of the wave function is the first problem to be solved for

  12. Evaluating transmission electron microscopy as a method for assessing the condition of archaeological wool

    DEFF Research Database (Denmark)

    Scharff, Annemette Bruselius; Jørgensen, Lise Bolt

    2017-01-01

    Transmission electron microscopy (TEM) was investigated to clarify the applicability of the method for assessing the condition of archaeological textiles from waterlogged environments. A description and evaluation of the TEM protocol is presented and the method was tested on new and artificially...

  13. 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...

  14. 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.

  15. Assignment of two ultrastructures formed by a mixture of hexonamides using autoradiography and electron microscopy

    NARCIS (Netherlands)

    Boettcher, Christoph; Boekema, Egbert J.; Fuhrhop, Juergen-H.

    1990-01-01

    The combined application of autoradiography and electron microscopy allowed the assignment of molecular components to individual micellar fibres in a mixed gel. Resolution was of the order of 0·1 µm. As a result, it was shown that bimolecular sheets of N-dodecyl-L-mannonamide (= L-Man-12) completely

  16. Aberration-corrected multipole Wien filter for energy-filtered x-ray photoemission electron microscopy

    OpenAIRE

    Niimi, Hironobu; Chun, Wang-Jae; Suzuki, Shushi; Asakura, Kiyotaka; Kato, Makoto

    2007-01-01

    The aberration of a multipole Wien filter for energy-filtered x-ray photoemission electron microscopy was analyzed and the optimized Fourier components of the electric and magnetic fields for the third-order aperture aberration corrections were obtained. It was found that the third-order aperture aberration correction requires 12 electrodes and magnetic poles. ©2007 American Institute of Physics

  17. Aberration-corrected multipole Wien filter for energy-filtered x-ray photoemission electron microscopy

    Science.gov (United States)

    Niimi, Hironobu; Chun, Wang-Jae; Suzuki, Shushi; Asakura, Kiyotaka; Kato, Makoto

    2007-06-01

    The aberration of a multipole Wien filter for energy-filtered x-ray photoemission electron microscopy was analyzed and the optimized Fourier components of the electric and magnetic fields for the third-order aperture aberration corrections were obtained. It was found that the third-order aperture aberration correction requires 12 electrodes and magnetic poles.

  18. Ultrathin sectioning of polymeric materials for low-voltage transmission electron microscopy. Relief on ultrathin sections

    Czech Academy of Sciences Publication Activity Database

    Lednický, František; Pientka, Zbyněk; Hromádková, Jiřina

    2003-01-01

    Roč. 42, č. 5 (2003), s. 1039-1047 ISSN 0022-2348 R&D Projects: GA AV ČR IBS4050008 Institutional research plan: CEZ:AV0Z4050913 Keywords : cutting ultrathin sections * low-voltage scanning transmission electron microscopy * polymer blend s Subject RIV: CD - Macromolecular Chemistry Impact factor: 0.679, year: 2003

  19. 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

  20. Study of the leakage field of magnetic force microscopy thin-film tips using electron holography

    NARCIS (Netherlands)

    Frost, B.G.; van Hulst, N.F.; Lunedei, E.; Matteucci, G.; Rikkers, E.

    1996-01-01

    Electron holography is applied for the study of the leakage field of thin-film ferromagnetic tips used as probes in magnetic force microscopy. We used commercially available pyramidal tips covered o­n o­ne face with a thin NiCo film, which were then placed in a high external magnetic field directed