Sample records for quantitative electron microscopy

  1. Using quantitative electron microscopy for process mineralogy applications

    Microsoft Academic Search

    P. Gottlieb; G. Wilkie; D. Sutherland; E. Ho-Tun; S. Suthers; K. Perera; B. Jenkins; S. Spencer; A. Butcher; J. Rayner

    2000-01-01

    Quantitative microscopy using scanning electron microscopy-based automatic measurement methods and data-processing techniques\\u000a that provide broad ranges of applications is very popular in the mining industry. These systems determine the quantities and\\u000a microtextures of the ore samples and metallurgical products to guide process development and troubleshoot processing problems.

  2. Quantitative characterization of electron detectors for transmission electron microscopy

    PubMed Central

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

    2013-01-01

    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 F416 scintillator-based cameras. We compare the results from our new method with published curves. PMID:24189638

  3. Quantitative analysis of coal and coal components by scanning electron microscopy and electron microprobe analysis

    Microsoft Academic Search

    F. R. Karner; H. H. Schobert; C. J. Zygarlicke; J. L. Hoff; T. P. Huber

    1987-01-01

    Quantitative compositional data for coal typically consists of bulk chemical data for organic elements and analyses of the inorganic elements in ash. This paper focuses on bringing together procedures primarily using scanning electron microscopy (SEM) and electron microprobe analysis (EMPA) to obtain the inorganic element content of bulk coal samples; the inorganic element content of specific lithotypes and macerals in

  4. Quantitative magnetic imaging at the nanometer scale by Ballistic Electron Magnetic Microscopy

    E-print Network

    Paris-Sud XI, Université de

    1 Quantitative magnetic imaging at the nanometer scale by Ballistic Electron Magnetic Microscopy M 11E, 35042 Rennes cedex, France We demonstrate quantitative ballistic electron magnetic microscopy nanostructured epitaxial Fe/Au/Fe/GaAs(001) spin-valves. In this epitaxial system, the magnetization

  5. Quantitative light and scanning electron microscopy of ferret sperm.

    PubMed

    Van der Horst, G; Curry, P T; Kitchin, R M; Burgess, W; Thorne, E T; Kwiatkowski, D; Parker, M; Atherton, R W

    1991-11-01

    Sperm were obtained via electroejaculation from Domestic ferret, (Mustela putorius furo), Siberian ferret (M. eversmanni), Black-footed ferret (M. nigripes), and a hybrid between Siberian and Domestic, called the Fitch ferret (M. sp.). Comparisons of sperm were made by four different microscopy techniques to determine whether differences exist among species. First, Nomarski differential interference microscopy could be used to distinguish domestic ferret sperm from the others on the basis of the structure of the posterior part of the acrosome. Second, both silver staining, which demonstrates argentophilic protein distribution, and scanning electron microscopy (SEM), revealed differences among the morphology of sperm for each species; variation in the unique appearance of the acrosome in ferret sperm was detected especially well by SEM. To quantify differences in morphology, five sperm head parameters were measured using image analysis; light microscopy produced significantly larger values than did SEM (all parameters and all species but Fitch), and there were significant differences owing to species for all parameters but one. Generally, our data demonstrate the value of complementary techniques to distinguish among sperm of closely related species and more specifically may help establish evolutionary relationships among the ferret species studied. In addition, they provide baseline data important for the captive breeding of the endangered Black-footed ferret. PMID:1793602

  6. Factors influencing quantitative liquid (scanning) transmission electron microscopy

    SciTech Connect

    Abellan Baeza, Patricia; Woehl, Taylor J.; Parent, Lucas R.; Browning, Nigel D.; Evans, James E.; Arslan, Ilke

    2014-04-15

    One of the experimental challenges in the study of nanomaterials in liquids in the (scanning) transmission electron microscope ((S)TEM) is gaining quantitative information. A successful experiment in the fluid stage will depend upon the ability to plan for sensitive factors such as the electron dose applied, imaging mode, acceleration voltage, beam-induced solution chemistry changes, and the specifics of solution reactivity. In this paper, we make use of a visual approach to show the extent of damage of different instrumental and experimental factors in liquid samples imaged in the (S)TEM. Previous results as well as new insights are presented to create an overview of beam-sample interactions identified for changing imaging and experimental conditions. This work establishes procedures to understand the effect of the electron beam on a solution, provides information to allow for a deliberate choice of the optimal experimental conditions to enable quantification, and identifies the experimental factors that require further analysis for achieving fully quantitative results in the liquid (S)TEM.

  7. Quantitative intercomparison of transmission electron microscopy, flow cytometry, and epifluorescence microscopy for nanometric particle analysis.

    PubMed

    Ferris, Matthew M; Stoffel, Carrie L; Maurer, Thain T; Rowlen, Kathy L

    2002-05-15

    Nanometric biological particles such as viruses have received increased attention in a wide range of scientific fields. Evaluation of viral contributions to environmental processes and the use of viruses in medical applications such as gene therapy require viruses to be routinely and accurately enumerated. There are a variety of existing techniques for counting viruses, namely, plaque assays, transmission electron microscopy (TEM), epifluorescence microscopy (EFM), and flow cytometry (FCM); each has advantages and disadvantages. While there have been attempts to intercompare some of these techniques to determine the most effective means to count viruses, no previous study used a technique-independent standard for quantitative comparison of collection efficiency, accuracy, and precision. In this work, polystyrene nanospheres were used as standards for the intercomparison of performance characteristics for TEM, EFM, FCM, as well as a custom-built flow cytometer (the Single Nanometric Particle Enumerator, SNaPE). EFM and SNaPE exhibited the highest degree of accuracy and precision, with particle concentrations deviating < or =5% from true and relative errors less than half that of TEM, EFM and SNaPE are also significantly more time and cost efficient than TEM. PMID:12009703

  8. Quantitative characterization of second-phase particles by atomic force microscopy and scanning electron microscopy

    Microsoft Academic Search

    B. Fruhstorfer; V. Mohles; R. Reichelt; E. Nembach

    2002-01-01

    It is demonstrated that the surface analysing methods atomic force microscopy (AFM) and scanning electron microscopy (SEM) can be used to determine accurately the average radius r and the volume fraction f of fine (r , 100 nm) spherical particles of secondary phases. Moreover the distribution function of the radii of individual particles can be accurately established by AFM and

  9. Development of a quantitative Correlative Light Electron Microscopy technique to study GLUT4 trafficking.

    PubMed

    Hodgson, Lorna; Tavaré, Jeremy; Verkade, Paul

    2014-03-01

    Correlative Light Electron Microscopy (CLEM) combines advantages of light microscopy and electron microscopy in one experiment to deliver information above and beyond the capability of either modality alone. There are many different CLEM techniques, each having its own special advantages but also its technical challenges. It is however the biological question that (should) drive(s) the development and application of a specific CLEM technique in order to provide the answer. Here we describe the development of a CLEM technique that is based on the Tokuyasu cryo immuno-gold labelling technique that has allowed us to quantitatively study GLUT4 trafficking. PMID:24390248

  10. Advanced Quantitative Transmission Electron Microscopy of Semiconductor Nanowires for Solar Cell Applications

    E-print Network

    Dunin-Borkowski, Rafal E.

    on semiconductor nanowires from an EU-funded solar- cell development project, AMON-RA. In the first example, AuAdvanced Quantitative Transmission Electron Microscopy of Semiconductor Nanowires for Solar Cell are of great interest for multiple applications, including solar cell heterostructures. However, accurate

  11. Compositional analysis of GaAs/AlGaAs heterostructures using quantitative scanning transmission electron microscopy

    SciTech Connect

    Kauko, H.; Helvoort, A. T. J. van [Department of Physics, Norwegian University of Science and Technology (NTNU), Trondheim (Norway); Zheng, C. L.; Glanvill, S. [Monash Centre for Electron Microscopy, Monash University, VIC 3800 (Australia)] [Monash Centre for Electron Microscopy, Monash University, VIC 3800 (Australia); Zhu, Y.; Etheridge, J., E-mail: joanne.etheridge@monash.edu [Monash Centre for Electron Microscopy, Monash University, VIC 3800 (Australia); Department of Materials Engineering, Monash University, VIC 3800 (Australia); Dwyer, C. [Monash Centre for Electron Microscopy, Monash University, VIC 3800 (Australia) [Monash Centre for Electron Microscopy, Monash University, VIC 3800 (Australia); Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, and Peter Grünberg Institute, Forschungszentrum Jülich, D-52425 Jülich (Germany); Munshi, A. M.; Fimland, B. O. [Department of Electronics and Telecommunications, Norwegian University of Science and Technology (NTNU), Trondheim (Norway)] [Department of Electronics and Telecommunications, Norwegian University of Science and Technology (NTNU), Trondheim (Norway)

    2013-12-02

    We demonstrate a method for compositional mapping of Al{sub x}Ga{sub 1–x}As heterostructures with high accuracy and unit cell spatial resolution using quantitative high angle annular dark field scanning transmission electron microscopy. The method is low dose relative to spectroscopic methods and insensitive to the effective source size and higher order lens aberrations. We apply the method to study the spatial variation in Al concentration in cross-sectioned GaAs/AlGaAs core-shell nanowires and quantify the concentration in the Al-rich radial band and the AlGaAs shell segments.

  12. Progress towards quantitative electron microscopy of catalysts Thomas W. Hansen1, Jakob B. Wagner1, Linus D. L. Duchstein1, Filippo Cavalca1,

    E-print Network

    Dunin-Borkowski, Rafal E.

    Progress towards quantitative electron microscopy of catalysts Thomas W. Dunin-Borkowski1 and Joerg R. Jinschek2 1Center for Electron Nanoscopy, Technical electron microscopy has resulted from the development of aberration correctors

  13. Second harmonic generation quantitative measurements on collagen fibrils through correlation to electron microscopy

    NASA Astrophysics Data System (ADS)

    Bancelin, S.; Aimé, C.; Gusachenko, I.; Kowalczuk, L.; Latour, G.; Coradin, T.; Schanne-Klein, M.-C.

    2015-03-01

    Type I collagen is a major structural protein in mammals that shows highly structured macromolecular organizations specific to each tissue. This biopolymer is synthesized as triple helices, which self-assemble into fibrils (Ø =10-300 nm) and further form various 3D organization. In recent years, Second Harmonic Generation (SHG) microscopy has emerged as a powerful technique to probe in situ the fibrillar collagenous network within tissues. However, this optical technique cannot resolve most of the fibrils and is a coherent process, which has impeded quantitative measurements of the fibril diameter so far. In this study, we correlated SHG microscopy with Transmission Electron Microscopy to determine the sensitivity of SHG microscopy and to calibrate SHG signals as a function of the fibril diameter in reconstructed collagen gels. To that end, we synthetized isolated fibrils with various diameters and successfully imaged the very same fibrils with both techniques, down to 30 nm diameter. We observed that SHG signals scaled as the fourth power of the fibril diameter, as expected from analytical and numerical calculations. This calibration was then applied to diabetic rat cornea in which we successfully recovered the diameter of hyperglycemia-induced fibrils in the Descemet's membrane without having to resolve them. Finally we derived the first hyperpolarizability from a single collagen triple helix which validates the bottom-up approach used to calculate the non-linear response at the fibrillar scale and denotes a parallel alignment of triple helices within the fibrils. These results represent a major step towards quantitative SHG imaging of nm-sized collagen fibrils.

  14. Quantitative magnetic imaging at the nanometer scale by ballistic electron magnetic microscopy

    SciTech Connect

    Herve, M.; Tricot, S.; Guezo, S.; Delhaye, G.; Lepine, B.; Schieffer, P.; Turban, P. [Departement Materiaux et Nanosciences, Institut de Physique de Rennes, UMR 6251, CNRS-Universite de Rennes 1, Campus de Beaulieu, Bat 11E, 35042 Rennes cedex (France)] [Departement Materiaux et Nanosciences, Institut de Physique de Rennes, UMR 6251, CNRS-Universite de Rennes 1, Campus de Beaulieu, Bat 11E, 35042 Rennes cedex (France)

    2013-06-21

    We demonstrate quantitative ballistic electron magnetic microscopy (BEMM) imaging of simple model Fe(001) nanostructures. We use in situ nanostencil shadow mask resistless patterning combined with molecular beam epitaxy deposition to prepare under ultra-high vacuum conditions nanostructured epitaxial Fe/Au/Fe/GaAs(001) spin-valves. In this epitaxial system, the magnetization of the bottom Fe/GaAs(001) electrode is parallel to the [110] direction, defining accurately the analysis direction for the BEMM experiments. The large hot-electron magnetoresistance of the Fe/Au/Fe/GaAs(001) epitaxial spin-valve allows us to image various stable magnetic configurations on the as-grown Fe(001) microstructures with a high sensitivity, even for small misalignments of both magnetic electrodes. The angular dependence of the hot-electron magnetocurrent is used to convert magnetization maps calculated by micromagnetic simulations into simulated BEMM images. The calculated BEMM images and magnetization rotation profiles show quantitative agreement with experiments and allow us to investigate the magnetic phase diagram of these model Fe(001) microstructures. Finally, magnetic domain reversals are observed under high current density pulses. This opens the way for further BEMM investigations of current-induced magnetization dynamics.

  15. Quantitative scanning electron microscopy of solitary chemoreceptor cells in cyprinids and other teleosts

    Microsoft Academic Search

    Kurt Kotrschal; Konrad Lorenz

    1992-01-01

    Synopsis Solitary chemosensory cells (SCC) occur in the epidermis of many lower, aquatic vertebrates. By scanning electron microscopy, SCC apices were counted and density distributions estimated along various transects at the head and body of 12 species of teleost fishes, 7 cyprinids, 2 perciforms, 2 catfish and 1 characinid. In contrast to taste buds (TB), the distribution of SCCs is

  16. Quantitative magnetic information from reciprocal space maps in transmission electron microscopy.

    PubMed

    Lidbaum, Hans; Rusz, Ján; Liebig, Andreas; Hjörvarsson, Björgvin; Oppeneer, Peter M; Coronel, Ernesto; Eriksson, Olle; Leifer, Klaus

    2009-01-23

    One of the most challenging issues in the characterization of magnetic materials is to obtain a quantitative analysis on the nanometer scale. Here we describe how electron magnetic circular dichroism (EMCD) measurements using the transmission electron microscope can be used for that purpose, utilizing reciprocal space maps. Applying the EMCD sum rules, an orbital to spin moment ratio of mL/mS=0.08+/-0.01 is obtained for Fe, which is consistent with the commonly accepted value. Hence, we establish EMCD as a quantitative element-specific technique for magnetic studies, using a widely available instrument with superior spatial resolution. PMID:19257384

  17. Electron microscopy.

    PubMed

    Luder, Hans U; Amstad-Jossi, Margrit

    2012-01-01

    Correlative light (LM) and transmission electron microscopic (TEM) analysis is useful, if ultrastructural details of cells need to be related to functional aspects which can only be examined at the LM level. The first protocol presented here introduces a relatively simple way of obtaining TEM images which, on the one hand, reveal ultrastructural details of individual cells and, on the other hand, are large enough to allow a correlation with light micrographs. The second protocol describes a technique for estimating mineral densities of hard tissues using backscattered electron images obtained with a scanning electron microscope. This technique can be used to analyze the mineralization processes which occur throughout tooth formation. PMID:22566049

  18. Dose limited reliability of quantitative annular dark field scanning transmission electron microscopy for nano-particle atom-counting.

    PubMed

    De Backer, A; Martinez, G T; MacArthur, K E; Jones, L; Béché, A; Nellist, P D; Van Aert, S

    2015-04-01

    Quantitative annular dark field scanning transmission electron microscopy (ADF STEM) has become a powerful technique to characterise nano-particles on an atomic scale. Because of their limited size and beam sensitivity, the atomic structure of such particles may become extremely challenging to determine. Therefore keeping the incoming electron dose to a minimum is important. However, this may reduce the reliability of quantitative ADF STEM which will here be demonstrated for nano-particle atom-counting. Based on experimental ADF STEM images of a real industrial catalyst, we discuss the limits for counting the number of atoms in a projected atomic column with single atom sensitivity. We diagnose these limits by combining a thorough statistical method and detailed image simulations. PMID:25511931

  19. Sub-0.1 nm-resolution quantitative scanning transmission electron microscopy without adjustable parameters

    SciTech Connect

    Dwyer, C. [Monash Centre for Electron Microscopy, Monash University, Victoria 3800 (Australia); Department of Materials Engineering, Monash University, Victoria 3800 (Australia); ARC Centre of Excellence for Design in Light Metals, Monash University, Victoria 3800 (Australia); Maunders, C. [Department of Materials Engineering, Monash University, Victoria 3800 (Australia); Zheng, C. L. [Monash Centre for Electron Microscopy, Monash University, Victoria 3800 (Australia); Weyland, M.; Etheridge, J. [Monash Centre for Electron Microscopy, Monash University, Victoria 3800 (Australia); Department of Materials Engineering, Monash University, Victoria 3800 (Australia); Tiemeijer, P. C. [FEI Electron Optics, P.O. Box 80066, 5600 KA Eindhoven (Netherlands)

    2012-05-07

    Atomic-resolution imaging in the scanning transmission electron microscope (STEM) constitutes a powerful tool for nanostructure characterization. Here, we demonstrate the quantitative interpretation of atomic-resolution high-angle annular dark-field (ADF) STEM images using an approach that does not rely on adjustable parameters. We measure independently the instrumental parameters that affect sub-0.1 nm-resolution ADF images, quantify their individual and collective contributions to the image intensity, and show that knowledge of these parameters enables a quantitative interpretation of the absolute intensity and contrast across all accessible spatial frequencies. The analysis also provides a method for the in-situ measurement of the STEM's effective source distribution.

  20. Clay microporosity in reservoir sandstones: An application of quantitative electron microscopy in petrophysical evaluation

    SciTech Connect

    Hurst, A. [Univ. of Aberdeen (United Kingdom); Nadeau, P.H. [Statoil, Forus (Norway)

    1995-04-01

    Clay mineral microporosity in sandstones is measured using computer-assisted image analysis of back-scattered electron micrographs of petrographic sections. Diagenetic kaolinite has a variety of textures with microporosity values ranging from 15 to 61%. Diagenetic chlorite has a generally uniform grain-coating texture and microporosity of about 50%. Fibrous illitic clays are difficult to characterize by the same method (an average value of 63% microporosity was recorded), but analysis of stereo-pair micrographs from scanning-electron microscopy analyses reveals that illite commonly has microporosity of approximately 90%. Clay microporosity data are used to calculate effective pore volumes and volumes of clay-bound water for clay minerals in sandstones. Converting from weight percent clay to volume percent clay is important. Microporosity data are valuable input to V{sub shale} evaluation where water saturation is associated with clay mineral type, texture, and volume.

  1. Correlative fractography: combining scanning electron microscopy and light microscopes for qualitative and quantitative analysis of fracture surfaces.

    PubMed

    Hein, Luis Rogerio de Oliveira; de Oliveira, José Alberto; de Campos, Kamila Amato

    2013-04-01

    Correlative fractography is a new expression proposed here to describe a new method for the association between scanning electron microscopy (SEM) and light microscopy (LM) for the qualitative and quantitative analysis of fracture surfaces. This article presents a new method involving the fusion of one elevation map obtained by extended depth from focus reconstruction from LM with exactly the same area by SEM and associated techniques, as X-ray mapping. The true topographic information is perfectly associated to local fracture mechanisms with this new technique, presented here as an alternative to stereo-pair reconstruction for the investigation of fractured components. The great advantage of this technique resides in the possibility of combining any imaging methods associated with LM and SEM for the same observed field from fracture surface. PMID:23402567

  2. Quantitative structural analysis of eukaryotic ribosomal RNA by scanning transmission electron microscopy

    SciTech Connect

    Oostergetel, G.T.; Wall, J.S.; Hainfeld, J.F.; Boublik, M.

    1985-09-01

    The conformation of 28S ribosomal RNA isolated from baby hamster kidney cells was studied by scanning transmission electron microscopy (STEM) and circular dichroic spectroscopy to establish the conditions under which STEM images of unstained freeze-dried rRNA are a meaningful representation of the conformation of rRNA in solution. The authors have determined the conformation of 28S rRNA under various buffer conditions, the molecular mass, the mass distribution, and the number of polynucleotide strands within the individual molecules, and the apparent radii of gyration. The 28S rRNA molecule is highly extended in water and becomes compact with increasing ionic strength. However, even in the reconstitution buffer the compactness does not reach a state in which the rRNA molecule appears structurally similar to the 60S ribosomal subunit. This approach has a broad application in high-resolution structural studies of nucleic acids and nucleic acid-protein interactions.

  3. Calibration-free quantitative surface topography reconstruction in scanning electron microscopy.

    PubMed

    Faber, E T; Martinez-Martinez, D; Mansilla, C; Ocelík, V; Hosson, J Th M De

    2015-01-01

    This work presents a new approach to obtain reliable surface topography reconstructions from 2D Scanning Electron Microscopy (SEM) images. In this method a set of images taken at different tilt angles are compared by means of digital image correlation (DIC). It is argued that the strength of the method lies in the fact that precise knowledge about the nature of the rotation (vector and/or magnitude) is not needed. Therefore, the great advantage is that complex calibrations of the measuring equipment are avoided. The paper presents the necessary equations involved in the methods, including derivations and solutions. The method is illustrated with examples of 3D reconstructions followed by a discussion on the relevant experimental parameters. PMID:25255373

  4. Size-dependent second virial coefficients of quantum dots from quantitative cryogenic electron microscopy.

    PubMed

    van Rijssel, J; Peters, V F D; Meeldijk, J D; Kortschot, R J; van Dijk-Moes, R J A; Petukhov, A V; Erné, B H; Philipse, A P

    2014-09-18

    Cryogenic transmission electron microscopy (cryo-TEM) is utilized to determine the second virial coefficient of osmotic pressure of PbSe quantum dots (QDs) dispersed in apolar liquid. Cryo-TEM images from vitrified samples provide snapshots of the equilibrium distribution of the particles. These snapshots yield radial distribution functions from which second virial coefficients are calculated, which agree with second virial coefficients determined with analytical centrifugation and small-angle X-ray scattering. The size dependence of the second virial coefficient points to an interparticle interaction that is proportional to the QD surface area. A plausible cause for this attraction is the interaction between the surface ions on adjacent QDs. PMID:25153168

  5. Accessibility of gonococcal and meningococcal surface antigens: immunogold labeling for quantitative electron microscopy.

    PubMed Central

    Pâques, M; Teppema, J S; Beuvery, E C; Abdillahi, H; Poolman, J T; Verkleij, A J

    1989-01-01

    The parallel application of two electron microscopic immunogold labeling procedures was used to assess the surface exposure and accessibility of gonococcal and meningococcal surface antigens. Monoclonal antibodies were used as markers for the surface antigens, i.e., outer membrane proteins and lipooligosaccharides. To evaluate the labeling densities obtained after incubation of whole bacteria in suspension or ultrathin cryosections of bacteria, a method of electron microscopic quantitation was developed. Incubation of whole bacterial suspensions with monoclonal antibodies and protein A-gold resulted in specific labeling of the bacterial surfaces. However, the labeling densities varied largely in each cell. By contrast, cryosections showed uniform heavy labeling densities at the surface of the outer membranes of all cells. Apparently, by sectioning the cells the antigen-masking barrier could be evaded, and steric hindrance was no longer restrictive. Thus, a better estimate of both the presence and the surface exposure, i.e., the accessibility of antigens, could be made. Such information is essential for us to better understand host-bacterial interactions and to develop new vaccines. Images PMID:2492264

  6. Characterization of individual submicrometer aerosol particles collected in Incheon, Korea, by quantitative transmission electron microscopy energy-dispersive X-ray spectrometry

    Microsoft Academic Search

    Hong Geng; Sujin Kang; Hae-Jin Jung; Marie Choël; HyeKyeong Kim; Chul-Un Ro

    2010-01-01

    For the last decade the Monte Carlo calculation method has been proven to be an excellent tool for accurately simulating electron-solid interactions in atmospheric individual particles of micrometer size. Although it was designed for application to scanning electron microscopy, in the present study it is demonstrated that the Monte Carlo calculation can also be applied in a quantitative single particle

  7. Quantitative characterization of agglomerates and aggregates of pyrogenic and precipitated amorphous silica nanomaterials by transmission electron microscopy

    PubMed Central

    2012-01-01

    Background The interaction of a nanomaterial (NM) with a biological system depends not only on the size of its primary particles but also on the size, shape and surface topology of its aggregates and agglomerates. A method based on transmission electron microscopy (TEM), to visualize the NM and on image analysis, to measure detected features quantitatively, was assessed for its capacity to characterize the aggregates and agglomerates of precipitated and pyrogenic synthetic amorphous silicon dioxide (SAS), or silica, NM. Results Bright field (BF) TEM combined with systematic random imaging and semi-automatic image analysis allows measuring the properties of SAS NM quantitatively. Automation allows measuring multiple and arithmetically complex parameters simultaneously on high numbers of detected particles. This reduces operator-induced bias and assures a statistically relevant number of measurements, avoiding the tedious repetitive task of manual measurements. Access to multiple parameters further allows selecting the optimal parameter in function of a specific purpose. Using principle component analysis (PCA), twenty-three measured parameters were classified into three classes containing measures for size, shape and surface topology of the NM. Conclusion The presented method allows a detailed quantitative characterization of NM, like dispersions of precipitated and pyrogenic SAS based on the number-based distributions of their mean diameter, sphericity and shape factor. PMID:22709926

  8. Correlative Instrumental Neutron Activation Analysis, Light Microscopy, Transmission Electron Microscopy, and X-ray Microanalysis for Qualitative and Quantitative Detection of Colloidal Gold Spheres in Biological Specimens

    NASA Astrophysics Data System (ADS)

    Hillyer, Julián F.; Albrecht, Ralph M.

    1998-10-01

    : Colloidal gold, conjugated to ligands or antibodies, is routinely used as a label for the detection of cell structures by light (LM) and electron microscopy (EM). To date, several methods to count the number of colloidal gold labels have been employed with limited success. Instrumental neutron activation analysis (INAA), a physical method for the analysis of the elemental composition of materials, can be used to provide a quantitative index of gold accumulation in bulk specimens. Given that gold is not naturally found in biological specimens in any substantial amount and that colloidal gold and ligand conjugates can be prepared to yield uniform bead sizes, the amount of label can be calculated in bulk biological samples by INAA. Here we describe the use of INAA, LM, transmission EM, and X-ray microanalysis (EDX) in a model to determine both distribution (localization) and amount of colloidal gold at the organ, tissue, cellular, and ultrastructural levels in whole animal systems following administration. In addition, the sensitivity for gold in biological specimens by INAA is compared with that of inductively coupled plasma mass spectrometry (ICP-MS). The correlative use of INAA, LM, TEM, and EDX can be useful, for example, in the quantitative and qualitative tracking of various labeled molecular species following administration in vivo.

  9. Correlative light-electron microscopy.

    PubMed

    Hanein, Dorit; Volkmann, Niels

    2011-01-01

    Recent advances in combining light and electron microscopy imaging techniques provide the means to correlate dynamic biological processes with the underlying structural correlates in situ. In this chapter, we provide snapshots of current advances targeting quantitative correlation of the dynamic state of a biological pathway with high-resolution structural information in the same window of time and space. PMID:21501820

  10. Quantitative electron microscopy shows uniform incorporation of triglycerides into existing lipid droplets.

    PubMed

    Cheng, Jinglei; Fujita, Akikazu; Ohsaki, Yuki; Suzuki, Michitaka; Shinohara, Yuki; Fujimoto, Toyoshi

    2009-09-01

    The lipid droplet (LD) is an organelle with a lipid ester core and a surface phospholipid monolayer. The mechanism of LD biogenesis is not well understood. The present study aimed to elucidate the LD growth process, for which we developed a new electron microscopic method that quantifies the proportion of existing and newly synthesized triglycerides in individual LDs. Our method takes advantage of the reactivity of unsaturated fatty acids and osmium tetroxide, which imparts LDs an electron density that reflects fatty acid composition. With this method, existing triglyceride-rich LDs in 3Y1 fibroblasts were observed to incorporate newly synthesized triglycerides at a highly uniform rate. This uniformity and its persistence even after microtubules were depolymerized suggest that triglycerides in fibroblasts are synthesized in the local vicinity of individual LDs and then incorporated. In contrast, LDs in 3T3-L1 adipocytes showed heterogeneity in the rate at which lipid esters were incorporated, indicating different mechanisms of LD growth in fibroblasts and adipocytes. PMID:19557427

  11. Quantitative multivariate data analysis in the examination of small signals from scanning transmission electron microscopy

    NASA Astrophysics Data System (ADS)

    Sarahan, Michael Carl

    Technological advancements have recently allowed scanning transmission electron microscopes (STEMs) to directly image atomic structures with better than 1 angstrom lateral resolution. Though the images contain chemical information about the sample through the relation of atomic number and thickness to image brightness, easy quantification of sample content using STEM images has remained elusive. This has been primarily due to the image imperfections caused by microscope instabilities, damaged or overly thick samples, or noise inherent in the high-angle annular dark field (HAADF) imaging technique. With recent increases in beam current, atomic resolution electron energy loss spectroscopic (EELS) mapping has made quantification possible over relatively large areas. However, the areas are still quite small in comparison to STEM images and require significantly greater acquisition times. This has excluded EELS from application to atomic-resolution quantification of beam-sensitive materials and limited the already minute sample volume studied in the STEM. This thesis has aimed to develop data analysis techniques that enhance the direct quantification of data extracted from HAADF-STEM images. Multivariate data analysis provided a means of studying correlated variations in image intensities, and was explored for application to the simple mass-thickness contrast of HAADF-STEM images. In this thesis, it is shown through image simulation that multivariate data analysis derives a linear relationship between the known sample composition and image intensity changes. The linear relationship is in the form of eigenimages and scores. Eigenimages correspond to characteristic intensity variations across many images. Scores relate the extent to which a characteristic intensity variation occurs in a particular image. These relationships can be derived many different ways, including principle component analysis, correspondence analysis, and independent component analysis. The method and implementation of these analyses are demonstrated on experimental data, giving local point defect information arising only from intensity variation. Calibration using simulated images allows quantification of individual column occupations.

  12. Application of Quantitative Analytical Electron Microscopy to the Mineral Content of Insect Cuticle

    NASA Astrophysics Data System (ADS)

    Rasch, Ron; Cribb, Bronwen W.; Barry, John; Palmer, Christopher M.

    2003-04-01

    Quantification of calcium in the cuticle of the fly larva Exeretonevra angustifrons was undertaken at the micron scale using wavelength dispersive X-ray microanalysis, analytical standards, and a full matrix correction. Calcium and phosphorus were found to be present in the exoskeleton in a ratio that indicates amorphous calcium phosphate. This was confirmed through electron diffraction of the calcium-containing tissue. Due to the pragmatic difficulties of measuring light elements, it is not uncommon in the field of entomology to neglect the use of matrix corrections when performing microanalysis of bulk insect specimens. To determine, firstly, whether such a strategy affects the outcome and secondly, which matrix correction is preferable, phi-rho (z) and ZAF matrix corrections were contrasted with each other and without matrix correction. The best estimate of the mineral phase was found to be given by using the phi-rho (z) correction. When no correction was made, the ratio of Ca to P fell outside the range for amorphous calcium phosphate, possibly leading to flawed interpretation of the mineral form when used on its own.

  13. A combined quantitative mass spectrometry and electron microscopy analysis of ribosomal 30S subunit assembly in E. coli

    PubMed Central

    Sashital, Dipali G; Greeman, Candacia A; Lyumkis, Dmitry; Potter, Clinton S; Carragher, Bridget; Williamson, James R

    2014-01-01

    Ribosome assembly is a complex process involving the folding and processing of ribosomal RNAs (rRNAs), concomitant binding of ribosomal proteins (r-proteins), and participation of numerous accessory cofactors. Here, we use a quantitative mass spectrometry/electron microscopy hybrid approach to determine the r-protein composition and conformation of 30S ribosome assembly intermediates in Escherichia coli. The relative timing of assembly of the 3? domain and the formation of the central pseudoknot (PK) structure depends on the presence of the assembly factor RimP. The central PK is unstable in the absence of RimP, resulting in the accumulation of intermediates in which the 3?-domain is unanchored and the 5?-domain is depleted for r-proteins S5 and S12 that contact the central PK. Our results reveal the importance of the cofactor RimP in central PK formation, and introduce a broadly applicable method for characterizing macromolecular assembly in cells. DOI: http://dx.doi.org/10.7554/eLife.04491.001 PMID:25313868

  14. A combined quantitative mass spectrometry and electron microscopy analysis of ribosomal 30S subunit assembly in E. coli.

    PubMed

    Sashital, Dipali G; Greeman, Candacia A; Lyumkis, Dmitry; Potter, Clinton S; Carragher, Bridget; Williamson, James R

    2014-01-01

    Ribosome assembly is a complex process involving the folding and processing of ribosomal RNAs (rRNAs), concomitant binding of ribosomal proteins (r-proteins), and participation of numerous accessory cofactors. Here, we use a quantitative mass spectrometry/electron microscopy hybrid approach to determine the r-protein composition and conformation of 30S ribosome assembly intermediates in Escherichia coli. The relative timing of assembly of the 3' domain and the formation of the central pseudoknot (PK) structure depends on the presence of the assembly factor RimP. The central PK is unstable in the absence of RimP, resulting in the accumulation of intermediates in which the 3'-domain is unanchored and the 5'-domain is depleted for r-proteins S5 and S12 that contact the central PK. Our results reveal the importance of the cofactor RimP in central PK formation, and introduce a broadly applicable method for characterizing macromolecular assembly in cells. PMID:25313868

  15. QEMSCAN° (Quantitative Evaluation of Minerals by Scanning Electron Microscopy): capability and application to fracture characterization in geothermal systems

    NASA Astrophysics Data System (ADS)

    Ayling, B.; Rose, P. E.; Zemach, E.; Drakos, P. S.; Petty, S.

    2011-12-01

    Fractures are important conduits for fluids in geothermal systems, and the creation and maintenance of fracture permeability is a fundamental aspect of EGS (Engineered Geothermal System) development. Hydraulic or chemical stimulation techniques are often employed to achieve this. In the case of chemical stimulation, an understanding of the minerals present in the fractures themselves is desirable to better design a stimulation effort (i.e. which chemical to use and how much). Borehole televiewer surveys provide important information about regional and local stress regimes and fracture characteristics (e.g. fracture aperture), and XRD is useful for examining bulk rock mineralogy, but neither technique is able to quantify the distribution of these minerals in fractures. QEMSCAN° is a fully-automated micro-analysis system that enables quantitative chemical analysis of materials and generation of high-resolution mineral maps and images as well as porosity structure. It uses a scanning electron microscopy platform (SEM) with an electron beam source in combination with four energy-dispersive X-ray spectrometers (EDS). The measured backscattered electron and electron-induced secondary X-ray emission spectra are used to classify sample mineralogy. Initial applications of QEMSCAN° technology were predominantly in the minerals industry and application to geothermal problems has remained limited to date. In this pilot study, the potential application of QEMSCAN° technology to fracture characterization was evaluated using samples of representative mineralized fractures in two geothermal systems (Newberry Volcano, Oregon and Brady's geothermal field, Nevada). QEMSCAN° results were compared with XRD and petrographic techniques. Nine samples were analyzed from each field, collected from the drill core in the 1000-1500 m depth range in two shallow wells (GEO-N2 at Newberry Volcano and BCH-3 at Brady's). The samples were prepared as polished thin sections for QEMSCAN° analysis. Results indicate that a sampling resolution of 10 ?m is sufficient to resolve fracture morphology and mineral zonation (where multiple episodes of mineralization occurred), and enables relatively fast data acquisition (3 cm2 can be analyzed in approximately 3 hours). Finer resolutions (down to 2.5 ?m) take significantly longer, but can be used to provide additional spatial detail in areas of interest after a low resolution (10 ?m) scan. Use of XRD data in conjunction with QEMSCAN° data is sometimes needed to distinguish geothermal alteration minerals with similar chemical compositions (clay minerals, micas and chlorite), however overall the technique appears to have excellent potential for geothermal applications.

  16. Virtual Scanning Electron Microscopy

    NSDL National Science Digital Library

    Michael W. Davidson

    This site from Florida State University features an interactive Java tutorial that explores various aspects of virtual scanning electron microscopy. Users can see how specimens appear when magnified in the virtual SEM. The site also features an image gallery and extensive information about different types of microscopy.

  17. The atomistic structure of a Sigma = 3, (111) grain boundary in NiAl, studied by quantitative high-resolution transmission electron microscopy

    Microsoft Academic Search

    K. Nadarzinski; F. Ernst

    1996-01-01

    The atomistic structure of the ? = 3, (111) gain boundary in NiAl has been determined by quantitative high-resolution transmission electron microscopy. In NiAl, which crystallizes in the B2 (CsCl) structure this grain boundary constitutes an 'incoherent twin boundary'. Using an atomic resolution microscope (JEM-ARM 130) we have obtained images of the grain-boundary structure at a point resolution of 0·105nm.

  18. Architecture of myocardial cells in human cardiac ventricles with concentric and eccentric hypertrophy as demonstrated by quantitative scanning electron microscopy

    Microsoft Academic Search

    Ken-ichi Sawada; Keishiro Kawamura

    1991-01-01

    Summary Scanning electron microscopy (SEM) was used to compare the shapes, size, and connections of cardiocytes in the midwall myofibers in the left ventricles of 5 normal hearts (266±16 g), 5 hearts with concentric hypertrophy (564±99 g) and 5 with eccentric hypertrophy (651±114 g), obtained at autopsy and fixed in formalin. In the myofibers from normal and hypertrophied hearts, intercalated

  19. Conventional transmission electron microscopy

    PubMed Central

    Winey, Mark; Meehl, Janet B.; O'Toole, Eileen T.; Giddings, Thomas H.

    2014-01-01

    Researchers have used transmission electron microscopy (TEM) to make contributions to cell biology for well over 50 years, and TEM continues to be an important technology in our field. We briefly present for the neophyte the components of a TEM-based study, beginning with sample preparation through imaging of the samples. We point out the limitations of TEM and issues to be considered during experimental design. Advanced electron microscopy techniques are listed as well. Finally, we point potential new users of TEM to resources to help launch their project. PMID:24482357

  20. Single particle electron microscopy

    Microsoft Academic Search

    Egbert J. Boekema; Mihaela Folea; Roman Kou?il

    2009-01-01

    Electron microscopy (EM) in combination with image analysis is a powerful technique to study protein structures at low, medium,\\u000a and high resolution. Since electron micrographs of biological objects are very noisy, improvement of the signal-to-noise ratio\\u000a by image processing is an integral part of EM, and this is performed by averaging large numbers of individual projections.\\u000a Averaging procedures can be

  1. Scanning electron microscopy of intestinal villous structures

    E-print Network

    Boyer, Edmond

    University, Manhattan, KS. 66506, U.S.A. Summary. Scanning Electron Microscope (SEM) was used to examineScanning electron microscopy of intestinal villous structures and their putative relation electron microscope (SEM) at 5 K.V. accelerating voltage. Quantitation of the intestinal structures

  2. Publications | High Resolution Electron Microscopy

    Cancer.gov

    Skip to main content High Resolution Electron Microscopy High Resolution Electron Microscopy Center for Cancer Research at the National Institutes of Health Main menu Home Research 3D Correlative Imaging Methods Development Protein Complexes Viral Entry Publications Image

  3. Gallery | High Resolution Electron Microscopy

    Cancer.gov

    Skip to main content High Resolution Electron Microscopy High Resolution Electron Microscopy Center for Cancer Research at the National Institutes of Health Main menu Home Research 3D Correlative Imaging Methods Development Protein Complexes Viral Entry Publications Image

  4. 3D imaging and quantitative analysis of small solubilized membrane proteins and their complexes by transmission electron microscopy

    PubMed Central

    Vahedi-Faridi, Ardeschir; Jastrzebska, Beata; Palczewski, Krzysztof; Engel, Andreas

    2013-01-01

    Inherently unstable, detergent-solubilized membrane protein complexes can often not be crystallized. For complexes that have a mass of >300 kDa, cryo-electron microscopy (EM) allows their three-dimensional (3D) structure to be assessed to a resolution that makes secondary structure elements visible in the best case. However, many interesting complexes exist whose mass is below 300 kDa and thus need alternative approaches. Two methods are reviewed: (i) Mass measurement in a scanning transmission electron microscope, which has provided important information on the stoichiometry of membrane protein complexes. This technique is applicable to particulate, filamentous and sheet-like structures. (ii) 3D-EM of negatively stained samples, which determines the molecular envelope of small membrane protein complexes. Staining and dehydration artifacts may corrupt the quality of the 3D map. Staining conditions thus need to be optimized. 3D maps of plant aquaporin SoPIP2;1 tetramers solubilized in different detergents illustrate that the flattening artifact can be partially prevented and that the detergent itself contributes significantly. Another example discussed is the complex of G protein-coupled receptor rhodopsin with its cognate G protein transducin. PMID:23267047

  5. 3D imaging and quantitative analysis of small solubilized membrane proteins and their complexes by transmission electron microscopy.

    PubMed

    Vahedi-Faridi, Ardeschir; Jastrzebska, Beata; Palczewski, Krzysztof; Engel, Andreas

    2013-02-01

    Inherently unstable, detergent-solubilized membrane protein complexes can often not be crystallized. For complexes that have a mass of >300 kDa, cryo-electron microscopy (EM) allows their three-dimensional (3D) structure to be assessed to a resolution that makes secondary structure elements visible in the best case. However, many interesting complexes exist whose mass is below 300 kDa and thus need alternative approaches. Two methods are reviewed: (i) Mass measurement in a scanning transmission electron microscope, which has provided important information on the stoichiometry of membrane protein complexes. This technique is applicable to particulate, filamentous and sheet-like structures. (ii) 3D-EM of negatively stained samples, which determines the molecular envelope of small membrane protein complexes. Staining and dehydration artifacts may corrupt the quality of the 3D map. Staining conditions thus need to be optimized. 3D maps of plant aquaporin SoPIP2;1 tetramers solubilized in different detergents illustrate that the flattening artifact can be partially prevented and that the detergent itself contributes significantly. Another example discussed is the complex of G protein-coupled receptor rhodopsin with its cognate G protein transducin. PMID:23267047

  6. Correlated light microscopy and electron microscopy.

    PubMed

    Sjollema, Klaas A; Schnell, Ulrike; Kuipers, Jeroen; Kalicharan, Ruby; Giepmans, Ben N G

    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 selected biomolecules or organelles but not the (ultra)structural context, as can be examined by electron microscopy (EM). LM and EM of the same cells, so-called correlative (or correlated) light and electron microscopy (CLEM), allow examining rare or dynamic events first by LM, and subsequently by EM. Here, we review progress in CLEM, with focus on matching the areas between different microscopic modalities. Moreover, we introduce a method that includes a virtual overlay and automated large-scale imaging, allowing to switch between most microscopes. Ongoing developments will revolutionize and standardize CLEM in the near future, which thus holds great promise to become a routine technique in cell biology. PMID:22857928

  7. Single electron tunneling force microscopy

    Microsoft Academic Search

    Ezra Barrus Bussmann

    2006-01-01

    The development and first application of a new scanning probe microscopy technique is described. This technique, called single-electron tunneling force microscopy (SETFM), is used to image and to perform spectroscopy of individual localized electronic states in completely nonconducting oxide surfaces. The SETFM detects single-electron tunneling events between a metallized atomic force microscope probe and individual electronic states by electrostatic force

  8. Silver stain for electron microscopy

    NASA Technical Reports Server (NTRS)

    Corbett, R. L.

    1972-01-01

    Ammoniacal silver stain used for light microscopy was adapted advantageously for use with very thin biological sections required for electron microscopy. Silver stain can be performed in short time, has more contrast, and is especially useful for low power electron microscopy.

  9. Electronic detectors for electron microscopy.

    PubMed

    Faruqi, A R; Henderson, R

    2007-10-01

    Due to the increasing popularity of electron cryo-microscopy (cryoEM) in the structural analysis of large biological molecules and macro-molecular complexes and the need for simple, rapid and efficient readout, there is a persuasive need for improved detectors. Commercial detectors, based on phosphor/fibre optics-coupled CCDs, provide adequate performance for many applications, including electron diffraction. However, due to intrinsic light scattering within the phosphor, spatial resolution is limited. Careful measurements suggest that CCDs have superior performance at lower resolution while all agree that film is still superior at higher resolution. Consequently, new detectors are needed based on more direct detection, thus avoiding the intermediate light conversion step required for CCDs. Two types of direct detectors are discussed in this review. First, there are detectors based on hybrid technology employing a separate pixellated sensor and readout electronics connected with bump bonds-hybrid pixel detectors (HPDs). Second, there are detectors, which are monolithic in that sensor and readout are all in one plane (monolithic active pixel sensor, MAPS). Our discussion is centred on the main parameters of interest to cryoEM users, viz. detective quantum efficiency (DQE), resolution or modulation transfer function (MTF), robustness against radiation damage, speed of readout, signal-to-noise ratio (SNR) and the number of independent pixels available for a given detector. PMID:17913494

  10. Welcome | High Resolution Electron Microscopy

    Cancer.gov

    For many years, electron microscopy has been used to image cells and tissues at high resolution. This technology, invented in the early 20th century, provided breakthrough information in the virology and cell biology fields. Over the last 15 to 20 years, however, rapid advances in imaging and computation technologies have expanded the usefulness of electron microscopy into new realms. Electron microscopy is now poised to close a critical "gap" in the structural biology field.

  11. Publications | High Resolution Electron Microscopy

    Cancer.gov

    Imaging biological objects with electrons involves principles similar to those used in light microscopy, except that electrons are used for illumination instead of photons and the lenses are magnetic instead of being optical. In the last five decades, electron microscopy (EM) helped to reveal basic cell structures in great detail, allowing researchers to visualize internal structure at resolutions that were about 100 times better than that obtained by optical microscopy.

  12. The effect of probe inaccuracies on the quantitative model-based analysis of high angle annular dark field scanning transmission electron microscopy images.

    PubMed

    Martinez, G T; De Backer, A; Rosenauer, A; Verbeeck, J; Van Aert, S

    2014-08-01

    Quantitative structural and chemical information can be obtained from high angle annular dark field scanning transmission electron microscopy (HAADF STEM) images when using statistical parameter estimation theory. In this approach, we assume an empirical parameterized imaging model for which the total scattered intensities of the atomic columns are estimated. These intensities can be related to the material structure or composition. Since the experimental probe profile is assumed to be known in the description of the imaging model, we will explore how the uncertainties in the probe profile affect the estimation of the total scattered intensities. Using multislice image simulations, we analyze this effect for Cs corrected and non-Cs corrected microscopes as a function of inaccuracies in cylindrically symmetric aberrations, such as defocus and spherical aberration of third and fifth order, and non-cylindrically symmetric aberrations, such as 2-fold and 3-fold astigmatism and coma. PMID:24462219

  13. Automated Quantitative Live Cell Fluorescence Microscopy

    PubMed Central

    Fero, Michael; Pogliano, Kit

    2010-01-01

    Advances in microscopy automation and image analysis have given biologists the tools to attempt large scale systems-level experiments on biological systems using microscope image readout. Fluorescence microscopy has become a standard tool for assaying gene function in RNAi knockdown screens and protein localization studies in eukaryotic systems. Similar high throughput studies can be attempted in prokaryotes, though the difficulties surrounding work at the diffraction limit pose challenges, and targeting essential genes in a high throughput way can be difficult. Here we will discuss efforts to make live-cell fluorescent microscopy based experiments using genetically encoded fluorescent reporters an automated, high throughput, and quantitative endeavor amenable to systems-level experiments in bacteria. We emphasize a quantitative data reduction approach, using simulation to help develop biologically relevant cell measurements that completely characterize the cell image. We give an example of how this type of data can be directly exploited by statistical learning algorithms to discover functional pathways. PMID:20591990

  14. Assessing camera performance for quantitative microscopy.

    PubMed

    Lambert, Talley J; Waters, Jennifer C

    2014-01-01

    Charge-coupled device and, increasingly, scientific complementary metal oxide semiconductor cameras are the most common digital detectors used for quantitative microscopy applications. Manufacturers provide technical specification data on the average or expected performance characteristics for each model of camera. However, the performance of individual cameras may vary, and many of the characteristics that are important for quantitation can be easily measured. Though it may seem obvious, it is important to remember that the digitized image you collect is merely a representation of the sample itself--and no camera can capture a perfect representation of an optical image. A clear understanding and characterization of the sources of noise and imprecision in your camera are important for rigorous quantitative analysis of digital images. In this chapter, we review the camera performance characteristics that are most critical for generating accurate and precise quantitative data and provide a step-by-step protocol for measuring these characteristics in your camera. PMID:24974021

  15. Research | High Resolution Electron Microscopy

    Cancer.gov

    Our research program primarily focuses on the development of technologies for 3D imaging using electron microscopy techniques, and on the use of these technologies to image cells, viruses and proteins at high resolution.

  16. Scanning Transmission Electron Microscopy

    SciTech Connect

    Lupini, Andrew R [ORNL; Rashkeev, Sergey [ORNL; Varela del Arco, Maria [ORNL; Borisevich, Albina Y [ORNL; Oxley, Mark P [ORNL; van Benthem, Klaus [ORNL; Peng, Yiping [ORNL; De Jonge, Niels [ORNL; Veith, Gabriel M [ORNL; Chisholm, Matthew F [ORNL; Pantelides, Sokrates T. [Vanderbilt University; Pennycook, Stephen J [ORNL

    2007-01-01

    Chemical characterization techniques have been essential tools in underpinning the explosion in nanotechnology in recent years and nanocharacterisation is a rapidly developing field. Contributions in this book from leading teams across the globe provide an overview of the different microscopic techniques now in regular use for the characterization of nanostructures. Essentially a handbook to all working in the field this indispensable resource provides a survey of microscopy based techniques with experimental procedures and extensive examples of state of the art characterization methods.

  17. Four-dimensional electron microscopy.

    PubMed

    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. PMID:20378810

  18. Quantitative Scanning Transmission Electron Microscopy

    E-print Network

    Akhmedov, Azer

    that are directly interpretable in terms of the atom column positions Twin boundary in a gold film #12;STEM vs://muller.research.engineering.cornell.edu/sites/WEELS/summer06/index.html #12;STEM vs. HRTEM · Atomic resolution images · "Coherent image" · Contrast reversals · Usually, image simulations are needed to interpret contrast in terms of atom column locations · Low angle

  19. Application of Electron Diffraction to Biological Electron Microscopy

    PubMed Central

    Glaeser, Robert M.; Thomas, Gareth

    1969-01-01

    Three methods by which electron diffraction may be applied to problems in electron microscopy are discussed from a fundamental point of view, and experimental applications with biological specimens are demonstrated for each case. It is shown that wide-angle electron diffraction provides valuable information for evaluating specimen damage that can occur either during specimen preparation or while in the electron beam. Dark-field electron microscopy can be used both to enhance the image contrast and to provide highly restricted and therefore highly specific information about the object. Low-angle electron diffraction provides quantitative information about the object structure in the range from 20 A to ? 1000 A. Lowangle electron diffraction also demonstrates the important role of Fourier contrast with biological specimens, which are usually characterized by structural features with dimensions of 20 A or larger. ImagesFigure 1Figure 2Figure 5Figure 6Figure 7Figure 8Figure 9Figure 10Figure 11Figure 13 PMID:4896898

  20. Dynamic imaging with electron microscopy

    ScienceCinema

    Campbell, Geoffrey; McKeown, Joe; Santala, Melissa

    2014-05-30

    Livermore researchers have perfected an electron microscope to study fast-evolving material processes and chemical reactions. By applying engineering, microscopy, and laser expertise to the decades-old technology of electron microscopy, the dynamic transmission electron microscope (DTEM) team has developed a technique that can capture images of phenomena that are both very small and very fast. DTEM uses a precisely timed laser pulse to achieve a short but intense electron beam for imaging. When synchronized with a dynamic event in the microscope's field of view, DTEM allows scientists to record and measure material changes in action. A new movie-mode capability, which earned a 2013 R&D 100 Award from R&D Magazine, uses up to nine laser pulses to sequentially capture fast, irreversible, even one-of-a-kind material changes at the nanometer scale. DTEM projects are advancing basic and applied materials research, including such areas as nanostructure growth, phase transformations, and chemical reactions.

  1. Magnetic force microscopy: quantitative issues in biomaterials.

    PubMed

    Passeri, Daniele; Dong, Chunhua; Reggente, Melania; Angeloni, Livia; Barteri, Mario; Scaramuzzo, Francesca A; De Angelis, Francesca; Marinelli, Fiorenzo; Antonelli, Flavia; Rinaldi, Federica; Marianecci, Carlotta; Carafa, Maria; Sorbo, Angela; Sordi, Daniela; Arends, Isabel Wce; Rossi, Marco

    2014-01-01

    Magnetic force microscopy (MFM) is an atomic force microscopy (AFM) based technique in which an AFM tip with a magnetic coating is used to probe local magnetic fields with the typical AFM spatial resolution, thus allowing one to acquire images reflecting the local magnetic properties of the samples at the nanoscale. Being a well established tool for the characterization of magnetic recording media, superconductors and magnetic nanomaterials, MFM is finding constantly increasing application in the study of magnetic properties of materials and systems of biological and biomedical interest. After reviewing these latter applications, three case studies are presented in which MFM is used to characterize: (i) magnetoferritin synthesized using apoferritin as molecular reactor; (ii) magnetic nanoparticles loaded niosomes to be used as nanocarriers for drug delivery; (iii) leukemic cells labeled using folic acid-coated core-shell superparamagnetic nanoparticles in order to exploit the presence of folate receptors on the cell membrane surface. In these examples, MFM data are quantitatively analyzed evidencing the limits of the simple analytical models currently used. Provided that suitable models are used to simulate the MFM response, MFM can be used to evaluate the magnetic momentum of the core of magnetoferritin, the iron entrapment efficiency in single vesicles, or the uptake of magnetic nanoparticles into cells. PMID:25050758

  2. Prototype cantilevers for quantitative lateral force microscopy

    SciTech Connect

    Reitsma, Mark G.; Gates, Richard S.; Friedman, Lawrence H.; Cook, Robert F. [Nanomechanical Properties Group, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States)

    2011-09-15

    Prototype cantilevers are presented that enable quantitative surface force measurements using contact-mode atomic force microscopy (AFM). The ''hammerhead'' cantilevers facilitate precise optical lever system calibrations for cantilever flexure and torsion, enabling quantifiable adhesion measurements and friction measurements by lateral force microscopy (LFM). Critically, a single hammerhead cantilever of known flexural stiffness and probe length dimension can be used to perform both a system calibration as well as surface force measurements in situ, which greatly increases force measurement precision and accuracy. During LFM calibration mode, a hammerhead cantilever allows an optical lever ''torque sensitivity'' to be generated for the quantification of LFM friction forces. Precise calibrations were performed on two different AFM instruments, in which torque sensitivity values were specified with sub-percent relative uncertainty. To examine the potential for accurate lateral force measurements using the prototype cantilevers, finite element analysis predicted measurement errors of a few percent or less, which could be reduced via refinement of calibration methodology or cantilever design. The cantilevers are compatible with commercial AFM instrumentation and can be used for other AFM techniques such as contact imaging and dynamic mode measurements.

  3. THEORETICAL FUNDAMENTALS AND EXPERIMENTAL MATERIALS AND DEFECT STUDIES USING QUANTITATIVE SCANNING ELECTRON MICROSCOPY CATHODOLUMINESCENCE\\/ELECTRON BEAM INDUCED CURRENT ON COMPOUND SEMICONDUCTORS

    Microsoft Academic Search

    S. Hildebrandt; J. Schreiber; W. Hergert; H. Uniewski; H. S. Leipner

    The theoretical fundamentals for the calculation of the local cathodoluminescence (CL) signal and electron beam induced current (EBIC) in the scanning electron microscope (SEM) are outlined. Especially, the simulation of the signal contrast profile behavior of individual dislocation configurations is reviewed. Existing analytical models and new numerical approaches are summarized. In addition to the evaluation of material parameters, the conception

  4. Characterization of municipal solid waste incineration (MSWI) bottom ash by scanning electron microscopy and quantitative energy dispersive X-ray microanalysis (SEM\\/EDX)

    Microsoft Academic Search

    C. Speiser; T. Baumann; R. Niessner

    2001-01-01

    Scanning electron microscopy (SEM) with energy-dispersive X-ray microanalysis (EDX) is frequently used for morphological\\u000a and qualitative chemical characterization of different materials. The applicability of this method for phase identification,\\u000a is, however, often underestimated. The application of SEM\\/EDX for the characterization of different phases in fresh and altered\\u000a municipal-waste incinerator bottom-ash samples with high lateral resolution is presented. Polished thin sections

  5. Diffused junctions in multicrystalline silicon solar cells studied by complementary scanning probe microscopy and scanning electron microscopy techniques

    Microsoft Academic Search

    Jennifer T. Heath; Chun-Sheng Jiang; Mowafak M. Al-Jassim

    2010-01-01

    The junction location in textured n+-p multicrystalline Si solar cell devices is quantitatively located. A comprehensive comparison is presented between secondary ion mass spectrometry (SIMS) and three microscopy techniques: scanning capacitance microscopy (SCM), scanning Kelvin probe microscopy (SKPM), and secondary electron contrast (SE) in the scanning electron microscope. The comparison includes capabilities of junction allocation, applicability of the measurement to

  6. Sen sin gan Electron Microscopy

    E-print Network

    to i n uire whether thisn ew subject has a role to playin Electron Microscopy (EM).In this paper, we theory may be usefulin EM. AMS SubjectC lassification: 94A12, 65C99, 68P30, 41A25, 15A52 Key Words of this paper is to describe the main elements of compressed sensing with an eye toward their possible use

  7. Former Lab Members | High Resolution Electron Microscopy

    Cancer.gov

    Skip to main content High Resolution Electron Microscopy High Resolution Electron Microscopy Center for Cancer Research at the National Institutes of Health Main menu Home Research 3D Correlative Imaging Methods Development Protein Complexes Viral Entry Publications Image

  8. Journal Covers | High Resolution Electron Microscopy

    Cancer.gov

    Skip to main content High Resolution Electron Microscopy High Resolution Electron Microscopy Center for Cancer Research at the National Institutes of Health Main menu Home Research 3D Correlative Imaging Methods Development Protein Complexes Viral Entry Publications Image

  9. Correlative fluorescence and electron microscopy.

    PubMed

    Schirra, Randall T; Zhang, Peijun

    2014-01-01

    Correlative fluorescence and electron microscopy (CFEM) is a multimodal technique that combines dynamic and localization information from fluorescence methods with ultrastructural data from electron microscopy, to give new information about how cellular components change relative to the spatiotemporal dynamics within their environment. In this review, we will discuss some of the basic techniques and tools of the trade for utilizing this attractive research method, which is becoming a very powerful tool for biology labs. The information obtained from correlative methods has proven to be invaluable in creating consensus between the two types of microscopy, extending the capability of each, and cutting the time and expense associated with using each method separately for comparative analysis. The realization of the advantages of these methods in cell biology has led to rapid improvement in the protocols and has ushered in a new generation of instruments to reach the next level of correlation-integration. Curr. Protoc. Cytom. 70:12.36.1-12.36.10. © 2014 by John Wiley & Sons, Inc. PMID:25271959

  10. Spectroscopic imaging in electron microscopy

    SciTech Connect

    Pennycook, Stephen J [ORNL; Colliex, C. [Universite Paris Sud, Orsay, France

    2012-01-01

    In the scanning transmission electron microscope, multiple signals can be simultaneously collected, including the transmitted and scattered electron signals (bright field and annular dark field or Z-contrast images), along with spectroscopic signals such as inelastically scattered electrons and emitted photons. In the last few years, the successful development of aberration correctors for the electron microscope has transformed the field of electron microscopy, opening up new possibilities for correlating structure to functionality. Aberration correction not only allows for enhanced structural resolution with incident probes into the sub-angstrom range, but can also provide greater probe currents to facilitate mapping of intrinsically weak spectroscopic signals at the nanoscale or even the atomic level. In this issue of MRS Bulletin, we illustrate the power of the new generation of electron microscopes with a combination of imaging and spectroscopy. We show the mapping of elemental distributions at atomic resolution and also the mapping of electronic and optical properties at unprecedented spatial resolution, with applications ranging from graphene to plasmonic nanostructures, and oxide interfaces to biology.

  11. Electronic multiconfocal-points microscopy

    NASA Astrophysics Data System (ADS)

    Benedetti, Pier A.; Evangelista, V.; Guidarini, D.; Vestri, S.

    1995-03-01

    A method for confocal optical microscopy is presented in which the role usually played by spatial modulators (pinhole or fiber) placed before the detector, is electronically emulated by an adaptive pixel-exclusion process performed at the level of an image detector. The technique is optimally suited to the construction of systems based on a multi-point illumination and detection approach, with the aid of conventional lamps and CCD image sensors. Due to its inherent simplicity and versatility, the proposed design can be efficiently employed in transmission, reflection and fluorescence microscopy, using trans- or epi-illumination configurations. The resulting advantages appear particularly relevant in biomedical applications, not only with the purpose of setting up practical and affordable instruments, but also in order to avoid specimen damage or signal saturation effects, as well as to obtain confocal images of light-absorbing microscopic structures.

  12. Correlative stochastic optical reconstruction microscopy and electron microscopy.

    PubMed

    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

  13. Morphology, morphometry and electron microscopy of HeLa cells infected with bovine Mycoplasma

    Microsoft Academic Search

    Edwin Boatman; Frank Cartwright; George Kenny

    1976-01-01

    The host-parasite relationship of HeLa M cells artificially infected with a bovine species of Mycoplasma was studied by light microscopy, transmission electron microscopy and scanning electron microscopy. The use of morphometry to quantitate some of the findings was explored. The parasites were seen in locations extracellular to the cell surface. The detection of small numbers of organisms by light microscopy

  14. Detection of Secondary and Supersecondary Structures of Proteins from Cryo-Electron Microscopy

    E-print Network

    Texas at Austin, University of

    in proteins. Keywords: protein structures detection, electron microscopy, stable/unstable manifolds, criticalDetection of Secondary and Supersecondary Structures of Proteins from Cryo-Electron Microscopy in three-dimensional electron microscopy (3D EM) have enabled the quantitative visualization

  15. Scanning Transmission Electron Microscopy for Nanostructure

    E-print Network

    Pennycook, Steve

    . Introduction The scanning transmission electron microscope (STEM) is an invaluable tool atom. The STEM works on the same principle as the normal scanning electron microscope (SEM), by forming152 6 Scanning Transmission Electron Microscopy for Nanostructure Characterization S. J. Pennycook

  16. Quantitative composition determination at the atomic level using model-based high-angle annular dark field scanning transmission electron microscopy.

    PubMed

    Martinez, G T; Rosenauer, A; De Backer, A; Verbeeck, J; Van Aert, S

    2014-02-01

    High angle annular dark field scanning transmission electron microscopy (HAADF STEM) images provide sample information which is sensitive to the chemical composition. The image intensities indeed scale with the mean atomic number Z. To some extent, chemically different atomic column types can therefore be visually distinguished. However, in order to quantify the atomic column composition with high accuracy and precision, model-based methods are necessary. Therefore, an empirical incoherent parametric imaging model can be used of which the unknown parameters are determined using statistical parameter estimation theory (Van Aert et al., 2009, [1]). In this paper, it will be shown how this method can be combined with frozen lattice multislice simulations in order to evolve from a relative toward an absolute quantification of the composition of single atomic columns with mixed atom types. Furthermore, the validity of the model assumptions are explored and discussed. PMID:24270003

  17. Ways to quantitatively detect antiphase disorder in GaP films grown on Si(0 0 1) by transmission electron microscopy

    NASA Astrophysics Data System (ADS)

    Németh, I.; Kunert, B.; Stolz, W.; Volz, K.

    2008-11-01

    The monolithic integration of GaP-based optoelectronic devices on exact-oriented (0 0 1) silicon (Si) substrates requires a defect-free GaP nucleation layer on the Si substrate. Antiphase disorder is a defect that inevitably arises at the GaP-Si interface if mono-atomic steps at the Si surface cannot be avoided. Using dynamic beam intensity simulations in electron microscopy, the present paper depicts transmission electron microscopic (TEM) dark field imaging conditions to examine the crystal polarity and hence the antiphase disorder. The methods are refined in such a way that even thin TEM specimens as well as very small (<10 nm) antiphase domains can be imaged at low sample tilts. Using the described techniques, one is able to show that the GaP growth temperature and growth mode play an important role in initiating the self-annihilation of antiphase boundaries by making them kink from {1 1 0} towards the {1 1 1} crystal planes.

  18. Electron microscopy studies of lithium aluminium hydrides

    Microsoft Academic Search

    C. M. Andrei; J. Walmsley; D. Blanchard; H. W. Brinks; R. Holmestad; B. C. Hauback

    2005-01-01

    The microstructure of LiAlD4 has been studied during the decomposition process using powder X-ray diffraction (PXD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Selected area diffraction (SAD) confirmed the existence of all the decomposed phases presented in the X-ray powder diffraction data. High-resolution transmission electron microscopy confirmed the presence of the LiAlD4 phase before decomposition. After the first

  19. CONFOCAL MICROSCOPY SYSTEM PERFORMANCE: QA TESTS, QUANTITATION AND SPECTROSCOPY

    EPA Science Inventory

    Confocal Microscopy System Performance: QA tests, Quantitation and Spectroscopy. Robert M. Zucker 1 and Jeremy M. Lerner 2, 1Reproductive Toxicology Division, National Health and Environmental Effects Research Laboratory, Office of Research Development, U.S. Environmen...

  20. Nanoscale analysis of clustered DNA damage after high-LET irradiation by quantitative electron microscopy--the heavy burden to repair.

    PubMed

    Lorat, Yvonne; Brunner, Christina U; Schanz, Stefanie; Jakob, Burkhard; Taucher-Scholz, Gisela; Rübe, Claudia E

    2015-04-01

    Low- and high-linear energy transfer (LET) ionising radiation are effective cancer therapies, but produce structurally different forms of DNA damage. Isolated DNA damage is repaired efficiently; however, clustered lesions may be more difficult to repair, and are considered as significant biological endpoints. We investigated the formation and repair of DNA double-strand breaks (DSBs) and clustered lesions in human fibroblasts after exposure to sparsely (low-LET; delivered by photons) and densely (high-LET; delivered by carbon ions) ionising radiation. DNA repair factors (pKu70, 53BP1, ?H2AX, and pXRCC1) were detected using immunogold-labelling and electron microscopy, and spatiotemporal DNA damage patterns were analysed within the nuclear ultrastructure at the nanoscale level. By labelling activated Ku-heterodimers (pKu70) the number of DSBs was determined in electron-lucent euchromatin and electron-dense heterochromatin. Directly after low-LET exposure (5 min post-irradiation), single pKu70 dimers, which reflect isolated DSBs, were randomly distributed throughout the entire nucleus with a linear dose correlation up to 30 Gy. Most euchromatic DSBs were sensed and repaired within 40 min, whereas heterochromatic DSBs were processed with slower kinetics. Essentially all DNA lesions induced by low-LET irradiation were efficiently rejoined within 24h post-irradiation. High-LET irradiation caused localised energy deposition within the particle tracks, and generated highly clustered DNA lesions with multiple DSBs in close proximity. The dimensions of these clustered lesions along the particle trajectories depended on the chromatin packing density, with huge DSB clusters predominantly localised in condensed heterochromatin. High-LET irradiation-induced clearly higher DSB yields than low-LET irradiation, with up to ? 500 DSBs per ?m(3) track volume, and large fractions of these heterochromatic DSBs remained unrepaired. Hence, the spacing and quantity of DSBs in clustered lesions influence DNA repair efficiency, and may determine the radiobiological outcome. PMID:25659339

  1. Quantitative phase microscopy with asynchronous digital holography

    PubMed Central

    Brown, William J.; Wax, Adam

    2009-01-01

    We demonstrate a new method of measuring quantitative phase in imaging of biological materials. This method, asynchronous digital holography, employs knowledge of a moving fringe created by acousto-optic modulators to execute phase-shifting interferometry using two near-simultaneous interferograms. The method can be used to obtain quantitative phase images of dynamic biological samples on millisecond time scales. We present results on a standard sample, and on live cell samples. PMID:19532543

  2. Quantitative phase microscopy through differential interference imaging

    Microsoft Academic Search

    Sharon V. King; Ariel Libertun; Rafael Piestun; Carol J. Cogswell; Chrysanthe Preza

    2008-01-01

    An extension of Nomarski differential interference contrast microscopy enables isotropic linear phase imaging through the combination of phase shifting, two directions of shear and Fourier-space integration using a modified spiral phase transform. We apply this method to simulated and experimentally acquired images of partially absorptive test objects. A direct comparison of the computationally determined phase to the true object phase

  3. Quantitative structured-illumination phase microscopy.

    PubMed

    Pavani, Sri Rama Prasanna; Libertun, Ariel R; King, Sharon V; Cogswell, Carol J

    2008-01-01

    We introduce a quantitative phase imaging method for homogeneous objects with a bright field transmission microscope by using an amplitude mask and a digital processing algorithm. A known amplitude pattern is imaged on the sample plane containing a thick phase object by placing an amplitude mask in the field diaphragm of the microscope. The phase object distorts the amplitude pattern according to its optical path length (OPL) profile, and the distorted pattern is recorded in a CCD detector. A digital processing algorithm then estimates the object's quantitative OPL profile based on a closed form analytical solution, which is derived using a ray optics model for objects with small OPL gradients. PMID:18157271

  4. Microstructural imaging techniques: a comparison between light and scanning electron microscopy

    Microsoft Academic Search

    Patrick W Trimby; David J Prior

    1999-01-01

    Both light microscopy and scanning electron microscopy are commonly used in microstructural studies of geological specimens. This contribution uses polished thin sections to analyse the same areas in two specimens using both microscopy techniques. The images from a quartz mylonite and a granodiorite are compared to quantitative crystallographic data obtained using electron backscatter diffraction (EBSD). The results indicate that light

  5. Relationship between the v?PO?/amide III ratio assessed by Raman spectroscopy and the calcium content measured by quantitative backscattered electron microscopy in healthy human osteonal bone.

    PubMed

    Roschger, Andreas; Gamsjaeger, Sonja; Hofstetter, Birgit; Masic, Admir; Blouin, Stéphane; Messmer, Phaedra; Berzlanovich, Andrea; Paschalis, Eleftherios P; Roschger, Paul; Klaushofer, Klaus; Fratzl, Peter

    2014-06-01

    Raman microspectroscopy and quantitative backscattered electron imaging (qBEI) of bone are powerful tools to investigate bone material properties. Both methods provide information on the degree of bone matrix mineralization. However, a head-to-head comparison of these outcomes from identical bone areas has not been performed to date. In femoral midshaft cross sections of three women, 99 regions (20×20 ?m²) were selected inside osteons and interstitial bone covering a wide range of matrix mineralization. As the focus of this study was only on regions undergoing secondary mineralization, zones exhibiting a distinct gradient in mineral content close to the mineralization front were excluded. The same regions were measured by both methods. We found a linear correlation (R²=0.75) between mineral/matrix as measured by Raman spectroscopy and the wt.?%Mineral/(100-wt.?%Mineral) as obtained by qBEI, in good agreement with theoretical estimations. The observed deviations of single values from the linear regression line were determined to reflect biological heterogeneities. The data of this study demonstrate the good correspondence between Raman and qBEI outcomes in describing tissue mineralization. The obtained correlation is likely sensitive to changes in bone tissue composition, providing an approach to detect potential deviations from normal bone. PMID:24919447

  6. Electron microscopy of specimens in liquid

    Microsoft Academic Search

    Niels de Jonge; Frances M. Ross

    2011-01-01

    Imaging samples in liquids with electron microscopy can provide unique insights into biological systems, such as cells containing labelled proteins, and into processes of importance in materials science, such as nanoparticle synthesis and electrochemical deposition. Here we review recent progress in the use of electron microscopy in liquids and its applications. We examine the experimental challenges involved and the resolution

  7. Fast electron microscopy via compressive sensing

    DOEpatents

    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.

  8. Quantitative interferometric microscopy cytometer based on regularized optical flow algorithm

    NASA Astrophysics Data System (ADS)

    Xue, Liang; Vargas, Javier; Wang, Shouyu; Li, Zhenhua; Liu, Fei

    2015-09-01

    Cell detections and analysis are important in various fields, such as medical observations and disease diagnoses. In order to analyze the cell parameters as well as observe the samples directly, in this paper, we present an improved quantitative interferometric microscopy cytometer, which can monitor the quantitative phase distributions of bio-samples and realize cellular parameter statistics. The proposed system is able to recover the phase imaging of biological samples in the expanded field of view via a regularized optical flow demodulation algorithm. This algorithm reconstructs the phase distribution with high accuracy with only two interferograms acquired at different time points simplifying the scanning system. Additionally, the method is totally automatic, and therefore it is convenient for establishing a quantitative phase cytometer. Moreover, the phase retrieval approach is robust against noise and background. Excitingly, red blood cells are readily investigated with the quantitative interferometric microscopy cytometer system.

  9. Energy-loss probability in electron microscopy

    NASA Astrophysics Data System (ADS)

    Echenique, P. M.; Bausells, J.; Rivacoba, A.

    1987-02-01

    New general results on the self-energy of fast electrons interacting with metal surfaces are presented with emphasis on the energy-loss problem in electron microscopy. Some applications to both spherical and planar targets are considered. Our results are relevant to the understanding of inelastic electron scattering near small structures, at the nanometer scale.

  10. Transmission Electron Microscopy: Overview and Challenges

    SciTech Connect

    Pennycook, Stephen J [ORNL; Lupini, Andrew R [ORNL; Borisevich, Albina Y [ORNL; Varela del Arco, Maria [ORNL; Peng, Yiping [ORNL; Nellist, Peter D. [Nion Company, WA; Duscher, Gerd J M [ORNL; Buczko, R. [University of Kentucky, Lexington; Pantelides, Sokrates T [ORNL

    2003-01-01

    We review recent advances in aberration-corrected scanning transmission electron microscopy that allow sub-Angstrom beams to be used for imaging and spectroscopy, with enormous improvement in sensitivity for single atom detection and the investigation of interfacial electronic structure. Comparison is made between the electronic and structural width of gate oxides, with interpretation through first-principles theory. Future developments are discussed.

  11. Scanning electron microscopy with polarization analysis (SEMPA)

    Microsoft Academic Search

    M. R. Scheinfein; J. Unguris; M. H. Kelley; D. T. Pierce; R. J. Celotta

    1990-01-01

    The high spatial resolution imaging of magnetic microstructure has important ramifications for both fundamental studies of magnetism and the technology surrounding the magnetic recording industry. One technique for imaging surface magnetic microstructure on the 10-nm-length scale is scanning electron microscopy with polarization analysis (SEMPA). This technique employs a scanning electron microscope (SEM) electron optical column to form a medium energy

  12. Image potential in scanning transmission electron microscopy

    Microsoft Academic Search

    A. Rivacoba; N. Zabala; J. Aizpurua

    2000-01-01

    In the framework of the classical dielectric theory, the role of the image potential in electron energy loss spectroscopy (EELS) of fast electrons commonly used in scanning transmission electron microscopy travelling near a surface is studied. Relativistic and dispersive corrections are evaluated to establish the range of validity of this theory. The spatial resolution of the EELS technique is discussed

  13. Correlative light and electron microscopy of GFP.

    PubMed

    Grabenbauer, Markus

    2012-01-01

    The correlation of light and electron microscopy (EM) is a powerful tool as it combines the investigation of dynamic processes in vivo with the resolution power of the electron microscope. The green fluorescent proteins (GFPs) and its derivatives revolutionized live-cell light microscopy. Hence, this review outlines correlative microscopy of GFP through photo-oxidation, a method that allows for the direct ultrastructural visualization of fluorophores upon illumination. Oxygen radicals generated during the GFP bleaching process photo-oxidize diaminobenzidine (DAB) into an electron dense precipitate that can be visualized both by routine EM of thin sections and by electron tomography for 3D analysis. There are different levels of correlative microscopy, i.e. the correlation of certain areas, cells, or organelles from light to EM, where photo-oxidation of DAB through GFP allows the highest possible degree--the correlation of specific molecules. PMID:22857926

  14. Electron Microscopy Characterization of Hybrid Metallic Nanomaterials

    Microsoft Academic Search

    Daisuke Shindo; Zentaro Akase

    2009-01-01

    In order to understand the excellent properties of nanoscale hybridized materials, it is very important to investigate the\\u000a microstructures and interfaces of these materials at the nanometer scale. In this chapter, we present the basic principles\\u000a of transmission electron microscopy and its applications to these materials. In addition to high-resolution transmission electron\\u000a microscopy (HREM) and high-angle annular dark-field (HAADF) scanning

  15. Extracting quantitative parameters from images in multiphoton microscopy

    Microsoft Academic Search

    Maxwell Stuart Zimmerley

    2010-01-01

    Coherent anti-Stokes Raman scattering (CARS) microscopy allows for fast, three-dimensionally resolved detection of molecules based on vibrational contrast. In CARS, the generated signal is nonlinearly dependent upon the concentration of the vibrational mode of interest. This makes it challenging to extract quantitative parameters (such as the concentration or orientation) from CARS images of biological and synthetic samples. Because of this,

  16. Quantitative Phase Microscopy of Live Biological Cell Dynamics

    NASA Astrophysics Data System (ADS)

    Shaked, Natan T.; Wax, Adam

    2010-04-01

    Interferometric phase microscopy of biological cell dynamics has the potential to provide a label-free quantitative tool for cell biology, as well as for medical diagnosis and monitoring. The current state of the art of this field, the open questions, and specific solutions developed in our laboratory will be presented.

  17. Contact | High Resolution Electron Microscopy

    Cancer.gov

    The long-term mission of our research program is to obtain an integrated, quantitative understanding of cells and viruses at molecular resolution. We take an interdisciplinary approach to this problem by combining novel technologies for 3D imaging with computational and cell biological tools.

  18. Quantitative biological imaging by ptychographic x-ray diffraction microscopy

    PubMed Central

    Giewekemeyer, Klaus; Thibault, Pierre; Kalbfleisch, Sebastian; Beerlink, André; Kewish, Cameron M.; Dierolf, Martin; Pfeiffer, Franz; Salditt, Tim

    2010-01-01

    Recent advances in coherent x-ray diffractive imaging have paved the way to reliable and quantitative imaging of noncompact specimens at the nanometer scale. Introduced a year ago, an advanced implementation of ptychographic coherent diffractive imaging has removed much of the previous limitations regarding sample preparation and illumination conditions. Here, we apply this recent approach toward structure determination at the nanoscale to biological microscopy. We show that the projected electron density of unstained and unsliced freeze-dried cells of the bacterium Deinococcus radiodurans can be derived from the reconstructed phase in a straightforward and reproducible way, with quantified and small errors. Thus, the approach may contribute in the future to the understanding of the highly disputed nucleoid structure of bacterial cells. In the present study, the estimated resolution for the cells was 85 nm (half-period length), whereas 50-nm resolution was demonstrated for lithographic test structures. With respect to the diameter of the pinhole used to illuminate the samples, a superresolution of about 15 was achieved for the cells and 30 for the test structures, respectively. These values should be assessed in view of the low dose applied on the order of ?1.3·105 Gy, and were shown to scale with photon fluence. PMID:20018650

  19. Quantitative Chemical Imaging with Multiplex Stimulated Raman Scattering Microscopy

    PubMed Central

    Fu, Dan; Lu, Fa-Ke; Zhang, Xu; Freudiger, Christian; Pernik, Douglas R.; Holtom, Gary; Xie, Xiaoliang Sunney

    2012-01-01

    Stimulated Raman scattering (SRS) microscopy is a newly developed label-free chemical imaging technique that overcomes the speed limitation of confocal Raman while avoiding the nonresonant-background problem of coherent anti-Stokes Raman scattering (CARS) microscopy. Previous demonstrations were limited to single Raman band measurement. We present a novel modulation multiplexing approach that allows real-time detection of multiple species using the fast Fourier-transform. We demonstrate quantitative determination of chemical concentration of a ternary mixture. Furthermore, two imaging applications are pursued: (1) quantitative determination of oil content, as well as pigment and protein concentration in microalgae cultures; (2) 3D high resolution imaging of blood, lipids, and protein distribution in ex vivo mouse skin tissue. We believe quantitative multiplex SRS uniquely combines the advantage of fast label-free imaging with the fingerprinting capability of Raman spectroscopy and enables numerous applications lipid biology as well as biomedical imaging. PMID:22316340

  20. Resolution measures in molecular electron microscopy

    PubMed Central

    Penczek, Pawel A.

    2011-01-01

    Resolution measures in molecular electron microscopy provide means to evaluate quality of macromolecular structures computed from sets of their two-dimensional line projections. When the amount of detail in the computed density map is low there are no external standards by which the resolution of the result can be judged. Instead, resolution measures in molecular electron microscopy evaluate consistency of the results in reciprocal space and present it as a one-dimensional function of the modulus of spatial frequency. Here we provide description of standard resolution measures commonly used in electron microscopy. We point out that the organizing principle is the relationship between these measures and the Spectral Signal-to-Noise Ratio of the computed density map. Within this framework it becomes straightforward to describe the connection between the outcome of resolution evaluations and the quality of electron microscopy maps, in particular, the optimum filtration, in the Wiener sense, of the computed map. We also provide a discussion of practical difficulties of evaluation of resolution in electron microscopy, particularly in terms of its sensitivity to data processing operations used during structure determination process in single particle analysis and in electron tomography. PMID:20888958

  1. Metallurgical applications of scanning transmission electron microscopy

    Microsoft Academic Search

    K. E. Easterling

    1977-01-01

    It is shown that scanning transmission electron microscopy (STEM) has followed two main lines of development, the pure STEM based upon a field emission electron source in which the emphasis is given to high resolution, and a combined system in which STEM is an attachment to a conventional transmission microscope (TEM + STEM). When used in combination with an energy

  2. Imaging carbon nanotubes by scanning electron microscopy

    Microsoft Academic Search

    Dmitriy Dikin

    2005-01-01

    Scanning electron microscopy (SEM) is used as a primary tool for imaging of nanostructures, including carbon nanotubes. Recent developments of the SEM technique have opened new capabilities for sample analysis at the nanoscale with potential industrial and metrological applications. We will discuss selective imaging of single-walled carbon nanotubes on insulators. The role of the electron beam parameters, effect of surrounding

  3. Publications | High Resolution Electron Microscopy

    Cancer.gov

    Zhang P, Land W, Lee S, Juliani J, Lefman J, Smith S, Germain D, Kessel M, Leapman R, Rouault TA and Subramaniam S. Electron tomography of degenerating neurons in mice with abnormal regulation of iron metabolism. J Struct Biol.

  4. Publications | High Resolution Electron Microscopy

    Cancer.gov

    Kuybeda O, Frank GA, Bartesaghi A, Borgnia M, Subramaniam S, and Sapiro G. A collaborative framework for 3D alignment and classification of heterogeneous subvolumes in cryo-electron tomography. J Struct Biol.

  5. Electron Microscopy Unit Snow Page

    NSDL National Science Digital Library

    Whether you are a climatologist or geoscientist looking for good image data or just want to cool off during a summer heatwave, this site from Beltsville Agricultural Research Center is not to be missed. Over 40 exquisite electron micrographs of snowflakes are housed here. A low temperature scanning electron microscope (SEM) was used in the imaging. Martian snow, rime and graupel, stereo images with cool .gif animations, and comparison of light and SEM images are showcased. Some images can be zoomed and informational summaries accompany the plates. An overview of agricultural applications of snow research and a publication list with some full-text links are also available.

  6. Scanning Electron Microscopy for Quantitative Small and Large Deformation Measurements Part II: Experimental Validation for Magnifications from 200 to 10,000

    Microsoft Academic Search

    M. A. Sutton; N. Li; D. Garcia; N. Cornille; J. J. Orteu; S. R. McNeill; H. W. Schreier; X. Li; A. P. Reynolds

    2007-01-01

    A combination of drift distortion removal and spatial distortion removal are performed to correct Scanning Electron Microscope\\u000a (SEM) images at both ?200 and ?10,000 magnification. Using multiple, time-spaced images and in-plane rigid body motions to\\u000a extract the relative displacement field throughout the imaging process, results from numerical simulations clearly demonstrate\\u000a that the correction procedures successfully remove both drift and spatial

  7. Location of lectin receptors on rat hepatocytes by transmission and scanning electron microscopy

    Microsoft Academic Search

    M. Horisberger; J. Rosset; M. Vonlanthen

    1978-01-01

    Summary Rexeptors for various lectins have been located on isolated hepatocytes by transmission and scanning electron microscopy, using gold markers of variable sizes. Quantitative data indicated that binding of some lectin markers depended upon their sizes.

  8. Subcellular quantitative optical diffraction tomography with digital holographic microscopy

    Microsoft Academic Search

    Florian Charrière; Jonas Kühn; Tristan Colomb; Etienne Cuche; Pierre Marquet; Christian Depeursinge

    2007-01-01

    Digital holographic microscopy (DHM) is an interferometric technique, providing quantitative mapping of the phase shift induced by semi-transparent microscopic specimens, such as cells, with sub-wavelength resolution along the optical axis. Thanks to actual PCs and CCDs, DHM provides nowadays cost-effective instruments for real-time measurements at very high acquisition rates, with sub-micron transverse resolution. However, DHM phase images do not reveal

  9. Active Pixel Sensors for electron microscopy

    NASA Astrophysics Data System (ADS)

    Denes, P.; Bussat, J.-M.; Lee, Z.; Radmillovic, V.

    2007-09-01

    The technology used for monolithic CMOS imagers, popular for cell phone cameras and other photographic applications, has been explored for charged particle tracking by the high-energy physics community for several years. This technology also lends itself to certain imaging detector applications in electron microscopy. We have been developing such detectors for several years at Lawrence Berkeley National Laboratory, and we and others have shown that this technology can offer excellent point-spread function, direct detection and high readout speed. In this paper, we describe some of the design constraints peculiar to electron microscopy and summarize where such detectors could play a useful role.

  10. Fast pixel shifting phase unwrapping algorithm in quantitative interferometric microscopy

    NASA Astrophysics Data System (ADS)

    Xu, Mingfei; Shan, Yanke; Yan, Keding; Xue, Liang; Wang, Shouyu; Liu, Fei

    2014-11-01

    Quantitative interferometric microscopy is an important method for observing biological samples such as cells and tissues. In order to obtain continuous phase distribution of the sample from the interferogram, phase extracting and phase unwrapping are both needed in quantitative interferometric microscopy. Phase extracting includes fast Fourier transform method and Hilbert transform method, etc., almost all of them are rapid methods. However, traditional unwrapping methods such as least squares algorithm, minimum network flow method, etc. are time-consuming to locate the phase discontinuities which lead to low processing efficiency. Other proposed high-speed phase unwrapping methods always need at least two interferograms to recover final phase distributions which cannot realize real time processing. Therefore, high-speed phase unwrapping algorithm for single interferogram is required to improve the calculation efficiency. Here, we propose a fast phase unwrapping algorithm to realize high-speed quantitative interferometric microscopy, by shifting mod 2? wrapped phase map for one pixel, then multiplying the original phase map and the shifted one, then the phase discontinuities location can be easily determined. Both numerical simulation and experiments confirm that the algorithm features fast, precise and reliable.

  11. [Pili annulati. A scanning electron microscopy study].

    PubMed

    Lalevi?-Vasi?, B; Poli?, D

    1988-01-01

    A case of ringed hair studied by light and electron microscopy is reported. The patient, a 20-year old girl, had been presenting with the hair abnormality since birth. At naked eye examination the hairs were dry, 6 to 7 cm long, and they showed dull and shining areas giving the scalp hair a scintillating appearance (fig. 1). Several samples of hair were taken and examined by light microscopy under white and polarized light. Hair shafts and cryo-fractured surfaces were examined by scanning electron microscopy. RESULTS. 1. Light microscopy. Lesions were found in every hair examined. There were abnormal, opaque and fusiform areas alternating with normal areas all along the hair shaft (fig. 2). The abnormal areas resulted from intracortical air-filled cavities. Fractures similar to those of trichorrhexis nodosa were found in the opaque areas of the distal parts of the hairs. 2. Scanning electron microscopy. A. Hair shaft surface. The abnormal areas showed a longitudinal, "curtain-like" folding of the cuticular cells which had punctiform depressions on their surface and worn free edges (fig. 4, 5, 6); trichorrhexis-type fractures were seen in the distal parts of the hair shafts (fig. 7, 8). Normal areas regularly presented with longitudinal, superficial, short and non-systematized depressions (fig. 9); the cuticular cells were worn, and there were places where the denuded cortex showed dissociated cortical fibres (fig. 10).(ABSTRACT TRUNCATED AT 250 WORDS) PMID:3415147

  12. Image potential in scanning transmission electron microscopy

    NASA Astrophysics Data System (ADS)

    Rivacoba, A.; Zabala, N.; Aizpurua, J.

    2000-09-01

    In the framework of the classical dielectric theory, the role of the image potential in electron energy loss spectroscopy (EELS) of fast electrons commonly used in scanning transmission electron microscopy travelling near a surface is studied. Relativistic and dispersive corrections are evaluated to establish the range of validity of this theory. The spatial resolution of the EELS technique is discussed for valence and core electron excitations. The effect of the quantal nature of the probe is also discussed. Finally, several problems involving planar surfaces, small particles, cylinders and truncated targets of interest in nanotechnology are studied.

  13. Experiences with remote electron microscopy

    SciTech Connect

    O'Keefe, Michael A.; Parvin, Bahram

    2002-02-22

    With the advent of a rapidly proliferating international computer network, it became feasible to consider remote operation of instrumentation normally operated locally. For modern electron microscopes, the growing automation and computer control of many instrumental operations facilitated the task of providing remote operation. In order to provide use of NCEM TEMs by distant users, a project was instituted in 1995 to place a unique instrument, a Kratos EM-1500 operating at 1.5MeV, on-line for remote use. In 1996, the Materials Microcharacterization Collaboratory (MMC) was created as a pilot project within the US Department of Energy's DOE2000 program to establish national collaboratories to provide access via the Internet to unique or expensive DOE research facilities as well as to expertise for remote collaboration, experimentation, production, software development, modeling, and measurement. A major LBNL contribution to the MMC was construction of DeepView, a microscope-independent computer-control system that could be ported to other MMC members to provide a common graphical user-interface (GUI) for control of any MMC instrument over the wide area network.

  14. Electron microscopy of whole mount metaphase chromosomes

    Microsoft Academic Search

    J. B. Rattner; A. Branch; B. A. Hamkalo

    1975-01-01

    Whole mount metaphase chromosomes, from cultured L cells, have been centrifuged onto grids and examined by electron microscopy. Compact and dispersed chromosome forms provide extensive ultrastructural information. Condensed chromosome arms appear as packed fibers with centromeric heterochromatin identifiable because it stains more intensely than the rest of the chromosome. Kinetochores are readily visible in these preparations. Under appropriate isolation conditions,

  15. Transmission Electron Microscopy in Semiconductor Manufacturing

    Microsoft Academic Search

    Heiko Stegmann; Hans-Jürgen Engelmann; Ehrenfried Zschech

    During the last two decades, the enduring shrinking of microelectron ic products has made transmission electron microscopy (TEM) an indispensable tool for structural characterization and chemical analysis of the smallest and most critical semiconductor structures. Moreover, the introduction of new materials and manufacturing processes raises new challenges for semiconductor device characterization and analysis. Because of its unsurpassed spatial resolution, its

  16. Organization of the Primate Retina: Electron Microscopy

    Microsoft Academic Search

    J. E. Dowling; B. B. Boycott

    1966-01-01

    The retinae of monkey and man have been studied by electron microscopy to identify cell types, their processes and synaptic contacts. In the inner plexiform layer, the morphological characteristics of the three types of cells (bipolar, ganglion and amacrine) are described and seven synaptic relationships are identified. The bipolar terminals contain ribbons at points of synaptic contact, and, at these

  17. Electron microscopy of Crotalaria pulmonary hypertension

    Microsoft Academic Search

    J. M. Kay; Paul Smith; Donald Heath

    1969-01-01

    The lungs of 11 rats fed on Crotalaria spectabilis seeds for periods ranging from 12 to 61 days were examined by both light and electron microscopy. The findings were compared with those obtained from nine control rats given a normal diet. Eight of the 11 test rats showed morphological evidence of pulmonary arterial hypertension in the form of right ventricular

  18. Electron microscopy facilities: access and training

    E-print Network

    Paxton, Anthony T.

    ://www-em.materials.ox.ac.uk/ 4/5 Oct 2010 Crispin Hetherington EM Facility #12;#12;This talk covers electron microscopy: other) ) SEM: (week 1 has Part IIs) and week 8 (w/b 29 Nov) Specimen Preparation, IT for EM #12;Crispin

  19. Archaeological Ceramics Studied by Scanning Electron Microscopy

    Microsoft Academic Search

    J. Froh

    2004-01-01

    The use of scanning electron microscopy combined with energy dispersive X-ray fluorescence analysis in studies of archaeological\\u000a pottery is discussed. The methods are described and results of their application to studies of Precolumbian glossy black pottery\\u000a from northern Peru are reported in some detail.

  20. Combined confocal Raman and quantitative phase microscopy system for biomedical diagnosis

    E-print Network

    Kang, Jeon Woong

    We have developed a novel multimodal microscopy system that incorporates confocal Raman, confocal reflectance, and quantitative phase microscopy (QPM) into a single imaging entity. Confocal Raman microscopy provides detailed ...

  1. Visualization of phytoplasmas using electron microscopy.

    PubMed

    Devonshire, B Jean

    2013-01-01

    The use of electron microscopy, both transmission and scanning, provides reliable and accurate methods for detecting phytoplasmas in plants. Our understanding of these pathogens, their morphology, development, and intracellular location in plants and insect vectors has been greatly increased through the use of these instruments. Development of techniques such as immunolabeling, cryofixation with freeze substitution or plunge freezing with direct transfer to the microscope stage, together with advances in instrumentation is enabling us to study these pathogens under conditions close to their native state. The visualization of fine detail and ultrastructure, using modern and established techniques, can only be appreciated by the magnification and spatial resolution offered in the electron microscopes. Now that the full sequencing of four phytoplasma genomes (to date) has been achieved, electron microscopy can play an important role in identifying and understanding specific gene functions. PMID:22987411

  2. Quantitative nanoscale characterisation by electron microscopy

    E-print Network

    Dunin-Borkowski, Rafal E.

    are in the nanometer range, thus explaining the interest in nanostructured materials or objects with nanometric that copper behaves completely differently mechanically when the grain size reaches nanometric dimensions

  3. Quantitative Determination of Tip Parameters in Piezoresponse Force Microscopy

    SciTech Connect

    Jesse, Stephen [ORNL; Kalinin, Sergei V [ORNL; Rodriguez, Brian J [ORNL; Eliseev, E. A. [National Academy of Science of Ukraine, Kiev, Ukraine; Morozovska, A. N. [National Academy of Science of Ukraine, Kiev, Ukraine

    2007-01-01

    One of the key limiting factors in the quantitative interpretation of piezoresponse force microscopy (PFM) is the lack of knowledge on the effective tip geometry. Here the authors derive analytical expressions for a 180{sup o} domain wall profile in PFM for the point charge, sphere plane, and disk electrode models of the tip. An approach for the determination of the effective tip parameters from the wall profile is suggested and illustrated for several ferroelectric materials. The calculated tip parameters can be used self-consistently for the interpretation of PFM resolution and spectroscopy data, i.e., linear imaging processes.

  4. Quantitative Determination on Tip Parameters in Piezoresponse Force Microscopy

    SciTech Connect

    Kalinin, Sergei V [ORNL; Jesse, Stephen [ORNL; Rodriguez, Brian J [ORNL; Eliseev, E. A. [National Academy of Science of Ukraine, Kiev, Ukraine; Gopalana, V. [Pennsylvania State University; Morozovska, A. N. [National Academy of Science of Ukraine, Kiev, Ukraine

    2007-01-01

    One of the key limiting factors in the quantitative interpretation of piezoresponse force microscopy (PFM) is the lack of knowledge on the effective tip geometry. Here the authors derive analytical expressions for a 180 degree domain wall profile in PFM for the point charge, sphere plane, and disk electrode models of the tip. An approach for the determination of the effective tip parameters from the wall profile is suggested and illustrated for several ferroelectric materials. The calculated tip parameters can be used self-consistently for the interpretation of PFM resolution and spectroscopy data, i.e., linear imaging processes.

  5. Background-free piezoresponse force microscopy for quantitative measurements

    NASA Astrophysics Data System (ADS)

    Wang, Wenbo; Geng, Yanan; Wu, Weida

    2014-02-01

    We report an effective method to remove the system-inherent background [Jungk et al., Appl. Phys. Lett. 91, 253511 (2007)] that is present in nominal piezoresponse force microscopy (PFM) setup. Control experiments performed in both ambient and ultrahigh vacuum environments indicate that the system-inherent background probably originates from the interactions between the modulation voltage and surface absorptions. By minimizing such interactions, background-free PFM results were obtained on glass, ?-quartz, hexagonal ErMnO3, and periodically poled LiNbO3. The removal of background signal allows quantitative measurements of local intrinsic piezoelectric response with high sensitivity (?0.1 pm/V).

  6. Quantitative polarized light microscopy of human cochlear sections

    PubMed Central

    Low, Jacob C. M.; Ober, Thomas J.; McKinley, Gareth H.; Stankovic, Konstantina M.

    2015-01-01

    Dysfunction of the inner ear is the most common cause of sensorineural hearing loss, which is the most common sensory deficit worldwide. Conventional imaging modalities are unable to depict the microanatomy of the human inner ear, hence the need to explore novel imaging modalities. We provide the first characterization of the polarization dependent optical properties of human cochlear sections using quantitative polarized light microscopy (qPLM). Eight pediatric cadaveric cochlear sections, aged 0 (term) to 24 months, were selected from the US National Temporal Bone Registry, imaged with qPLM and analyzed using Image J. Retardance of the bony otic capsule and basilar membrane were substantially higher than that of the stria vascularis, spiral ganglion neurons, organ of Corti and spiral ligament across the half turns of the spiraling cochlea. qPLM provides quantitative information about the human inner ear, and awaits future exploration in vivo. PMID:25780749

  7. Quantitative single-molecule imaging by confocal laser scanning microscopy.

    PubMed

    Vukojevic, Vladana; Heidkamp, Marcus; Ming, Yu; Johansson, Björn; Terenius, Lars; Rigler, Rudolf

    2008-11-25

    A new approach to quantitative single-molecule imaging by confocal laser scanning microscopy (CLSM) is presented. It relies on fluorescence intensity distribution to analyze the molecular occurrence statistics captured by digital imaging and enables direct determination of the number of fluorescent molecules and their diffusion rates without resorting to temporal or spatial autocorrelation analyses. Digital images of fluorescent molecules were recorded by using fast scanning and avalanche photodiode detectors. In this way the signal-to-background ratio was significantly improved, enabling direct quantitative imaging by CLSM. The potential of the proposed approach is demonstrated by using standard solutions of fluorescent dyes, fluorescently labeled DNA molecules, quantum dots, and the Enhanced Green Fluorescent Protein in solution and in live cells. The method was verified by using fluorescence correlation spectroscopy. The relevance for biological applications, in particular, for live cell imaging, is discussed. PMID:19011092

  8. 4D ULTRAFAST ELECTRON DIFFRACTION, CRYSTALLOGRAPHY, AND MICROSCOPY

    E-print Network

    Ihee, Hyotcherl

    4D ULTRAFAST ELECTRON DIFFRACTION, CRYSTALLOGRAPHY, AND MICROSCOPY Annu. Rev. Phys. Chem. 2006. 57 Electron Crystallography (Nov. 15) · Ultrafast Electron Microscopy (Nov. 20) Schedule #12;Introduction #12;#12;#12;#12;#12;#12;#12;#12;#12;#12; #12;#12;#12;#12;#12;#12;4D ULTRAFAST ELECTRON DIFFRACTION, CRYSTALLOGRAPHY, AND MICROSCOPY Annu. Rev

  9. Frontiers of in situ electron microscopy

    DOE PAGESBeta

    Zheng, Haimei; Zhu, Yimei; Meng, Shirley Ying

    2015-01-01

    In situ transmission electron microscopy (TEM) has become an increasingly important tool for materials characterization. It provides key information on the structural dynamics of a material during transformations and the correlation between structure and properties of materials. With the recent advances in instrumentation, including aberration corrected optics, sample environment control, the sample stage, and fast and sensitive data acquisition, in situ TEM characterization has become more and more powerful. In this article, a brief review of the current status and future opportunities of in situ TEM is included. It also provides an introduction to the six articles covered by inmore »this issue of MRS Bulletin explore the frontiers of in situ electron microscopy, including liquid and gas environmental TEM, dynamic four-dimensional TEM, nanomechanics, ferroelectric domain switching studied by in situ TEM, and state-of-the-art atomic imaging of light elements (i.e., carbon atoms) and individual defects.« less

  10. Quantitative thermal characterization of microelectronic devices by using CCD-based thermoreflectance microscopy

    NASA Astrophysics Data System (ADS)

    Kim, Dong Uk; Ryu, Seon Young; Kim, Jun Ki; Chang, Ki Soo

    2014-03-01

    A thermoreflectance microscopy (TRM) system has emerged as a non-destructive and non-contact tool for a high resolution thermal imaging technique for micro-scale electronic and optoelectronic devices. Quantitative imaging of the temperature distribution is necessary for elaborate thermal characterization under operating conditions, such as thermal profiling and performance and reliability analysis. We introduce here a straightforward TRM system to perform quantitative thermal characterization of microelectronics devices. The quantitative imaging of the surface temperature distribution of a polysilicon micro-resistor is obtained by a lock-in measurement technique and calibration process in the conventional CCD-based widefield microscope. To confirm the quantitative thermal measurement, the measured thermal information is compared to that obtained with an infrared thermography (IRT) system. In addition to quantitative surface temperature distribution, the sub-micron defects on microelectronic devices can be clearly distinguished from the thermoreflectance images, which are hardly perceptible with a conventional widefield microscopy system. The thermal resolution of the proposed TRM system is experimentally determined by measuring standard deviation values of thermoreflectance data with respect to the iteration number. The spatial and thermal resolutions of our system are measured ~670 nm and ~13 mK, respectively. We believe that quantitative thermal imaging in the TRM system can be used for improvement of microelectronic devices and integrated circuit (IC) designs.

  11. Correlative Photoactivated Localization and Scanning Electron Microscopy

    PubMed Central

    Kopek, Benjamin G.; Shtengel, Gleb; Grimm, Jonathan B.; Clayton, David A.; Hess, Harald F.

    2013-01-01

    The ability to localize proteins precisely within subcellular space is crucial to understanding the functioning of biological systems. Recently, we described a protocol that correlates a precise map of fluorescent fusion proteins localized using three-dimensional super-resolution optical microscopy with the fine ultrastructural context of three-dimensional electron micrographs. While it achieved the difficult simultaneous objectives of high photoactivated fluorophore preservation and ultrastructure preservation, it required a super-resolution optical and specialized electron microscope that is not available to many researchers. We present here a faster and more practical protocol with the advantage of a simpler two-dimensional optical (Photoactivated Localization Microscopy (PALM)) and scanning electron microscope (SEM) system that retains the often mutually exclusive attributes of fluorophore preservation and ultrastructure preservation. As before, cryosections were prepared using the Tokuyasu protocol, but the staining protocol was modified to be amenable for use in a standard SEM without the need for focused ion beam ablation. We show the versatility of this technique by labeling different cellular compartments and structures including mitochondrial nucleoids, peroxisomes, and the nuclear lamina. We also demonstrate simultaneous two-color PALM imaging with correlated electron micrographs. Lastly, this technique can be used with small-molecule dyes as demonstrated with actin labeling using phalloidin conjugated to a caged dye. By retaining the dense protein labeling expected for super-resolution microscopy combined with ultrastructural preservation, simplifying the tools required for correlative microscopy, and expanding the number of useful labels we expect this method to be accessible and valuable to a wide variety of researchers. PMID:24204771

  12. Scanning electron microscopy of cold gases

    E-print Network

    Santra, Bodhaditya

    2015-01-01

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

  13. Scanning electron microscopy of cold gases

    NASA Astrophysics Data System (ADS)

    Santra, Bodhaditya; Ott, Herwig

    2015-06-01

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

  14. High resolution scanning electron microscopy of plasmodesmata

    Microsoft Academic Search

    Sarah Brecknock; Teresa P. Dibbayawan; Maret Vesk; Peter A. Vesk; Christine Faulkner; Deborah A. Barton; Robyn L. Overall

    Symplastic transport occurs between neighbouring plant cells through functionally and structurally dynamic channels called\\u000a plasmodesmata (PD). Relatively little is known about the composition of PD or the mechanisms that facilitate molecular transport\\u000a into neighbouring cells. While transmission electron microscopy (TEM) provides 2-dimensional information about the structural\\u000a components of PD, 3-dimensional information is difficult to extract from ultrathin sections. This study

  15. 4D electron microscopy: principles and applications.

    PubMed

    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 achievable with short intense pulses containing a large number of electrons, however, are limited to tens of nanometers and nanoseconds, respectively. This is because Coulomb repulsion is significant in such a pulse, and the electrons spread in space and time, thus limiting the beam coherence. It is therefore not possible to image the ultrafast elementary dynamics of complex transformations. The challenge was to retain the high spatial resolution of a conventional TEM while simultaneously enabling the temporal resolution required to visualize atomic-scale motions. In this Account, we discuss the development of four-dimensional ultrafast electron microscopy (4D UEM) and summarize techniques and applications that illustrate the power of the approach. In UEM, images are obtained either stroboscopically with coherent single-electron packets or with a single electron bunch. Coulomb repulsion is absent under the single-electron condition, thus permitting imaging, diffraction, and spectroscopy, all with high spatiotemporal resolution, the atomic scale (sub-nanometer and femtosecond). The time resolution is limited only by the laser pulse duration and energy carried by the electron packets; the CCD camera has no bearing on the temporal resolution. In the regime of single pulses of electrons, the temporal resolution of picoseconds can be attained when hundreds of electrons are in the bunch. The applications given here are selected to highlight phenomena of different length and time scales, from atomic motions during structural dynamics to phase transitions and nanomechanical oscillations. We conclude with a brief discussion of emerging methods, which include scanning ultrafast electron microscopy (S-UEM), scanning transmission ultrafast electron microscopy (ST-UEM) with convergent beams, and time-resolved imaging of biological structures at ambient conditions with environmental cells. PMID:22967215

  16. Quantitative Phase Microscopy: how to make phase data meaningful

    PubMed Central

    Goldstein, Goldie; Creath, Katherine

    2014-01-01

    The continued development of hardware and associated image processing techniques for quantitative phase microscopy has allowed superior phase data to be acquired that readily shows dynamic optical volume changes and enables particle tracking. Recent efforts have focused on tying phase data and associated metrics to cell morphology. One challenge in measuring biological objects using interferometrically obtained phase information is achieving consistent phase unwrapping and -dimensions and correct for temporal discrepanices using a temporal unwrapping procedure. The residual background shape due to mean value fluctuations and residual tilts can be removed automatically using a simple object characterization algorithm. Once the phase data are processed consistently, it is then possible to characterize biological samples such as myocytes and myoblasts in terms of their size, texture and optical volume and track those features dynamically. By observing optical volume dynamically it is possible to determine the presence of objects such as vesicles within myoblasts even when they are co-located with other objects. Quantitative phase microscopy provides a label-free mechanism to characterize living cells and their morphology in dynamic environments, however it is critical to connect the measured phase to important biological function for this measurement modality to prove useful to a broader scientific community. In order to do so, results must be highly consistent and require little to no user manipulation to achieve high quality nynerical results that can be combined with other imaging modalities. PMID:25309099

  17. Quantitative phase microscopy: how to make phase data meaningful

    NASA Astrophysics Data System (ADS)

    Goldstein, Goldie; Creath, Katherine

    2014-03-01

    The continued development of hardware and associated image processing techniques for quantitative phase microscopy has allowed superior phase data to be acquired that readily shows dynamic optical volume changes and enables particle tracking. Recent efforts have focused on tying phase data and associated metrics to cell morphology. One challenge in measuring biological objects using interferometrically obtained phase information is achieving consistent phase unwrapping and background shape removal throughout a sequence of images. Work has been done to improve the phase unwrapping in two-dimensions and correct for temporal discrepanices using a temporal unwrapping procedure. The residual background shape due to mean value fluctuations and residual tilts can be removed automatically using a simple object characterization algorithm. Once the phase data are processed consistently, it is then possible to characterize biological samples such as myocytes and myoblasts in terms of their size, texture and optical volume and track those features dynamically. By observing optical volume dynamically it is possible to determine the presence of objects such as vesicles within myoblasts even when they are co-located with other objects. Quantitative phase microscopy provides a label-free mechanism to characterize living cells and their morphology in dynamic environments, however it is critical to connect the measured phase to important biological function for this measurement modality to prove useful to a broader scientific community. In order to do so, results must be highly consistent and require little to no user manipulation to achieve high quality nynerical results that can be combined with other imaging modalities.

  18. Quantitative Phase Microscopy: how to make phase data meaningful.

    PubMed

    Goldstein, Goldie; Creath, Katherine

    2014-03-12

    The continued development of hardware and associated image processing techniques for quantitative phase microscopy has allowed superior phase data to be acquired that readily shows dynamic optical volume changes and enables particle tracking. Recent efforts have focused on tying phase data and associated metrics to cell morphology. One challenge in measuring biological objects using interferometrically obtained phase information is achieving consistent phase unwrapping and -dimensions and correct for temporal discrepanices using a temporal unwrapping procedure. The residual background shape due to mean value fluctuations and residual tilts can be removed automatically using a simple object characterization algorithm. Once the phase data are processed consistently, it is then possible to characterize biological samples such as myocytes and myoblasts in terms of their size, texture and optical volume and track those features dynamically. By observing optical volume dynamically it is possible to determine the presence of objects such as vesicles within myoblasts even when they are co-located with other objects. Quantitative phase microscopy provides a label-free mechanism to characterize living cells and their morphology in dynamic environments, however it is critical to connect the measured phase to important biological function for this measurement modality to prove useful to a broader scientific community. In order to do so, results must be highly consistent and require little to no user manipulation to achieve high quality nynerical results that can be combined with other imaging modalities. PMID:25309099

  19. Quantitative Imaging of Single Unstained Magnetotactic Bacteria by Coherent X-ray Diffraction Microscopy.

    PubMed

    Fan, Jiadong; Sun, Zhibin; Zhang, Jian; Huang, Qingjie; Yao, Shengkun; Zong, Yunbing; Kohmura, Yoshiki; Ishikawa, Tetsuya; Liu, Hong; Jiang, Huaidong

    2015-06-16

    Novel coherent diffraction microscopy provides a powerful lensless imaging method to obtain a better understanding of the microorganism at the nanoscale. Here we demonstrated quantitative imaging of intact unstained magnetotactic bacteria using coherent X-ray diffraction microscopy combined with an iterative phase retrieval algorithm. Although the signal-to-noise ratio of the X-ray diffraction pattern from single magnetotactic bacterium is weak due to low-scattering ability of biomaterials, an 18.6 nm half-period resolution of reconstructed image was achieved by using a hybrid input-output phase retrieval algorithm. On the basis of the quantitative reconstructed images, the morphology and some intracellular structures, such as nucleoid, poly?-hydroxybutyrate granules, and magnetosomes, were identified, which were also confirmed by scanning electron microscopy and energy dispersive spectroscopy. With the benefit from the quantifiability of coherent diffraction imaging, for the first time to our knowledge, an average density of magnetotactic bacteria was calculated to be ?1.19 g/cm(3). This technique has a wide range of applications, especially in quantitative imaging of low-scattering biomaterials and multicomponent materials at nanoscale resolution. Combined with the cryogenic technique or X-ray free electron lasers, the method could image cells in a hydrated condition, which helps to maintain their natural structure. PMID:26006162

  20. HIV: The Initial Invasion | High Resolution Electron Microscopy

    Cancer.gov

    Skip to main content High Resolution Electron Microscopy High Resolution Electron Microscopy Center for Cancer Research at the National Institutes of Health Main menu Home Research 3D Correlative Imaging Methods Development Protein Complexes Viral Entry Publications Image

  1. New Developments in Transmission Electron Microscopy for Nanotechnology**

    E-print Network

    Wang, Zhong L.

    New Developments in Transmission Electron Microscopy for Nanotechnology** By Zhong Lin Wang* 1. Electron Microscopy and Nanotechnology Nanotechnology, as an international initiative for science manufacturing are the foundation of nanotechnology. Tracking the historical background of why nanotechnology

  2. Metallothioneins for correlative light and electron microscopy.

    PubMed

    Fernández de Castro, Isabel; Sanz-Sánchez, Laura; Risco, Cristina

    2014-01-01

    Structural biologists have been working for decades on new strategies to identify proteins in cells unambiguously. We recently explored the possibilities of using the small metal-binding protein, metallothionein (MT), as a tag to detect proteins in transmission electron microscopy. It had been reported that, when fused with a protein of interest and treated in vitro with gold salts, a single MT tag will build an electron-dense gold cluster ~1 nm in diameter; we provided proof of this principle by demonstrating that MT can be used to detect intracellular proteins in bacteria and eukaryotic cells. The method, which is compatible with a variety of sample processing techniques, allows specific detection of proteins in cells with exceptional sensitivity. We illustrated the applicability of the technique in a series of studies to visualize the intracellular distribution of bacterial and viral proteins. Immunogold labeling was fundamental to confirm the specificity of the MT-gold method. When proteins were double-tagged with green fluorescent protein and MT, direct correlative light and electron microscopy allowed visualization of the same macromolecular complexes with different spatial resolutions. MT-gold tagging might also become a useful tool for mapping proteins into the 3D-density maps produced by (cryo)-electron tomography. New protocols will be needed for double or multiple labeling of proteins, using different versions of MT with fluorophores of different colors. Further research is also necessary to render the MT-gold labeling procedure compatible with immunogold labeling on Tokuyasu cryosections and with cryo-electron microscopy of vitreous sections. PMID:25287836

  3. IMAGING RED BLOOD CELL DYNAMICS BY QUANTITATIVE PHASE MICROSCOPY

    PubMed Central

    Popescu, Gabriel; Park, YoungKeun; Choi, Wonshik; Dasari, Ramachandra R.; Feld, Michael S.; Badizadegan, Kamran

    2008-01-01

    Red blood cells (RBCs) play a crucial role in health and disease, and structural and mechanical abnormalities of these cells have been associated with important disorders such as Sickle cell disease and hereditary cytoskeletal abnormalities. Although several experimental methods exist for analysis of RBC mechanical properties, optical methods stand out as they enable collecting mechanical and dynamic data from live cells without physical contact and without the need for exogenous contrast agents. In this report, we present quantitative phase microscopy techniques that enable imaging RBC membrane fluctuations with nanometer sensitivity at arbitrary time scales from milliseconds to hours. We further provide a theoretical framework for extraction of membrane mechanical and dynamical properties using time series of quantitative phase images. Finally, we present an experimental approach to extend quantitative phase imaging to 3-dimensional space using tomographic methods. By providing non-invasive methods for imaging mechanics of live cells, these novel techniques provide an opportunity for high-throughput analysis and study of RBC mechanical properties in health and disease. PMID:18387320

  4. Electron microscopy investigations of nanoparticles for cancer diagnostic applications

    Microsoft Academic Search

    Ai Leen Koh

    2009-01-01

    This dissertation concerns electron microscopy characterization of magnetic (MNP) and surface enhanced Raman scattering (SERS) nanoparticles for in-vitro cancer diagnostic applications. Electron microscopy is an essential characterization tool owing to its (sub) nanometer spatial resolution. Structural information about the nanoparticles can be obtained using transmission electron microscopy (TEM), which can in turn be correlated to their physical characteristics. The scanning

  5. Imaging lipid droplets by electron microscopy.

    PubMed

    Fujimoto, Toyoshi; Ohsaki, Yuki; Suzuki, Michitaka; Cheng, Jinglei

    2013-01-01

    The lipid droplet (LD) is different from other cellular organelles in that most of its volume is made of lipid esters and its surface is lined by a phospholipid monolayer. This uniquely lipid-dominant structure poses a problem for electron microscopy (EM) because the aldehydes commonly used as a fixative do not react with most lipids. To circumvent this difficulty and utilize the high resolving power of EM, many methods have been developed. In this chapter, we discuss methods that have been used and/or are potentially useful to study LDs. The methods include conventional EM to observe the LD core, cryoelectron microscopy to observe the LD surface, freeze-substitution, immunoelectron microscopy (pre-embedding, post-embedding, and cryosectioning methods), and freeze-fracture. Each method has strong and weak points and therefore some caution is necessary in interpreting the obtained results. In combination with methods of other disciplines, the electron microscopic techniques should contribute significantly to solving the remaining questions on LDs. PMID:24099296

  6. Electron Microscopy: an Analytical Tool for Solid State Physicists

    NASA Astrophysics Data System (ADS)

    van Tendeloo, Gustaaf

    2013-03-01

    For too long the electron microscope has been considered as ``a big magnifying glass.'' Modern electron microscopy however has evolved into an analytical technique, able to provide quantitative data on structure, composition, chemical bonding and magnetic properties. Using lens corrected instruments it is now possible to determine atom shifts at interfaces with a precision of a few picometer; chemical diffusion at these interfaces can be imaged down to atomic scale. The chemical nature of the surface atoms can be visualized and even the bonding state of the elements (e.g. Mn2+ versus Mn3+) can be detected on an atomic scale. Electron microscopy is by principle a projection technique, but the final dream is to obtain atomic info of materials in three dimensions. We will show that this is no longer a dream, but that it is possible using advanced microscopy. We will show evidence of determining the valence change Ce4+ versus Ce3+ at the surface of a CeO2 nanocrystal; the atomic shifts at the interface between LaAlO3 and SrTiO3 and the 3D relaxation of a Au nanocrystal.

  7. Molecular Expressions: Virtual Scanning Electron Microscopy

    NSDL National Science Digital Library

    2007-06-30

    This Java applet allows students to interactively explore various specimens as they appear under a scanning electron microscope (SEM). SEM is a type of electron microscope that images the surface of a sample with a high-energy beam of electrons. It can produce very high-resolution photos of details as small as 1-5 nanometers. Choose from a cockroach, pollen grain, a diatomic molecule, a gecko foot, a jellyfish, and more. Users first adjust the focus, contrast, and brightness of the specimen to optimize its appearance. Then they use a slider to incrementally increase the magnification up to 10,000x. This item is part of a much larger collection of optics and microscopy materials developed at the National High Magnetic Field Laboratory at Florida State University.

  8. Sewage coliphages studied by electron microscopy.

    PubMed Central

    Ackermann, H W; Nguyen, T M

    1983-01-01

    Sewage was enriched with 35 Escherichia coli strains, and sediments of enrichment cultures were studied in the electron microscope. They contained up to 10 varieties of morphologically different particles. T-even-type phages predominated in 14 samples. Thirteen phages were enriched, representing the families Myoviridae (seven), Styloviridae (two), Podoviridae (three), and Microviridae (one). Twelve of these corresponded to known enterobacterial phage species, namely, 121, K19, FC3-9, O1, 9266, T2, 16-19, kappa, beta 4, N4, T7, and phi X174. Cubic RNA phages and filamentous phages were not detected. Types 121 and 9266 have previously been observed only in Romania and South Africa. Identification by morphology is usually simple. Our investigative technique is qualitative and will not detect all phages present. Most enrichment strains are polyvalent, and electron microscopy is always required for phage identification. In a general way, electron microscopy seems to be the method of choice for investigation of phage geography and ecology. Images PMID:6847179

  9. Phase-contrast scanning transmission electron microscopy.

    PubMed

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

    2015-06-01

    This report introduces the first results obtained using phase-contrast scanning transmission electron microscopy (P-STEM). A carbon-film phase plate (PP) with a small center hole is placed in the condenser aperture plane so that a phase shift is introduced in the incident electron waves except those passing through the center hole. A cosine-type phase-contrast transfer function emerges when the phase-shifted scattered waves interfere with the non-phase-shifted unscattered waves, which passed through the center hole before incidence onto the specimen. The phase contrast resulting in P-STEM is optically identical to that in phase-contrast transmission electron microscopy that is used to provide high contrast for weak phase objects. Therefore, the use of PPs can enhance the phase contrast of the STEM images of specimens in principle. The phase shift resulting from the PP, whose thickness corresponds to a phase shift of ?, has been confirmed using interference fringes displayed in the Ronchigram of a silicon single crystal specimen. The interference fringes were found to abruptly shift at the edge of the PP hole by ?. PMID:25748570

  10. Fluorescent microscopy approaches of quantitative soil microbial analysis

    NASA Astrophysics Data System (ADS)

    Ivanov, Konstantin; Polyanskaya, Lubov

    2015-04-01

    Classical fluorescent microscopy method was used during the last decades in various microbiological studies of terrestrial ecosystems. The method provides representative results and simple application which is allow to use it both as routine part of amplitudinous research and in small-scaled laboratories. Furthermore, depending on research targets a lot of modifications of fluorescent microscopy method were established. Combination and comparison of several approaches is an opportunity of quantitative estimation of microbial community in soil. The first analytical part of the study was dedicated to soil bacterial density estimation by fluorescent microscopy in dynamic of several 30-days experiments. The purpose of research was estimation of changes in soil bacterial community on the different soil horizons under aerobic and anaerobic conditions with adding nutrients in two experimental sets: cellulose and chitin. Was modified the nalidixic acid method for inhibition of DNA division of gram-negative bacteria, and the method provides the quantification of this bacterial group by fluorescent microscopy. Established approach allowed to estimate 3-4 times more cells of gram-negative bacteria in soil. The functions of actinomyces in soil polymer destruction are traditionally considered as dominant in comparison to gram-negative bacterial group. However, quantification of gram-negative bacteria in chernozem and peatland provides underestimation of classical notion for this bacterial group. Chitin introduction had no positive effect to gram-negative bacterial population density changes in chernozem but concurrently this nutrient provided the fast growing dynamics at the first 3 days of experiment both under aerobic and anaerobic conditions. This is confirming chitinolytic activity of gram-negative bacteria in soil organic matter decomposition. At the next part of research modified method for soil gram-negative bacteria quantification was compared to fluorescent in situ hybridization method (FISH). This approach was used for evaluation of contribution of each gram-negative bactera group. No significant difference between the main soil gram-negative bacterial groups (phylum Proteobacteria and Bacteroidetes) was found both under anaerobic and anaerobic conditions in chernozem in the topsoil. Thus soil gram-negative bacteria play an important ecological role in natural polymer degradation as common group of microorganisms. Another approach with using cascade filtration technique for bacterial population density estimation in chernozem was compared to classical method of fluorescent microscopy. Quantification of soil bacteria with cascade filtration provided by filters with different diameters and filtering of soil suspension in fixed amount. In comparison to the classical fluorescent microscopy method the modification with filtration of soil suspension provided to quantify more bacterial cells. Thus biomass calculation results of soil bacteria by using classical fluorescent microscopy could be underestimated and combination with cascade filtration technique allow to avoid potential experimental error. Thereby, combination and comparison of several fluorescent microscopy methods modifications established during the research provided miscellaneous approaches in soil bacteria quantification and analysis of ecological roles of soil microorganisms.

  11. Quantitative fluorescent speckle microscopy (QFSM) to measure actin dynamics.

    PubMed

    Mendoza, Michelle C; Besson, Sebastien; Danuser, Gaudenz

    2012-10-01

    Quantitative fluorescent speckle microscopy (QFSM) is a live-cell imaging method to analyze the dynamics of macromolecular assemblies with high spatial and temporal resolution. Its greatest successes were in the analysis of actin filament and adhesion dynamics in the context of cell migration and microtubule dynamics in interphase and the meiotic/mitotic spindle. Here, focus is on the former application to illustrate the procedures of FSM imaging and the computational image processing that extracts quantitative information from these experiments. QFSM is advantageous over other methods because it measures the movement and turnover kinetics of the actin filament (F-actin) network in living cells across the entire field of view. Experiments begin with the microinjection of fluorophore-labeled actin into cells, which generate a low ratio of fluorescently labeled to endogenously unlabeled actin monomers. Spinning disk confocal or wide-field imaging then visualizes fluorophore clusters (two to eight actin monomers) within the assembled F-actin network as speckles. QFSM software identifies and computationally tracks and utilizes the location, appearance, and disappearance of speckles to derive network flows and maps of the rate of filament assembly and disassembly. PMID:23042526

  12. Comprehensive quantitative evaluation of FLIM-FRET microscopy

    NASA Astrophysics Data System (ADS)

    Wallrabe, Horst; Sun, Yuangsheng; Svindrych, Zdenek; Periasamy, Ammasi

    2015-03-01

    Average lifetime between the usually bi-exponential double-label specimen and a mono-exponential single donor sample serves as a basis for the calculation of the average energy transfer efficiency (E). This semi-quantitative approach however does not fully explore cellular functions, such as endosomal pH differences, specific morphological features, examining sub-populations and the like. We applied a different, quantitative Region-of-Interest (ROI)-based method in 2 live-cell assays by TCSPC FLIM-FRET microscopy: a 5 amino-acid linked FRET standard and mouse pituitary cells expressing a dimerized C/EBP?-bZip transcription factor in the nucleus, both tagged with Cerulean (C) and Venus (V). ROIs with different selection thresholds were generated and compared. Average lifetimes are similar, but ratios between them and other subtle differences are revealed by comprehensive distribution information. Following published references, we also explored 3 different methods to calculate FLIM-FRET energy transfer efficiencies for the Cerulean- Venus constructs, producing differences and supporting the long-held notion that E is called 'apparent' efficiency. FRET's greatest contribution continues to be exploring changes taking place at the cellular level and quantifying differences in relative terms between control and variables.

  13. Quantitative Fluorescent Speckle Microscopy (QFSM) to Measure Actin Dynamics

    PubMed Central

    Mendoza, Michelle C.; Besson, Sebastien; Danuser, Gaudenz

    2012-01-01

    Quantitative Fluorescent Speckle Microscopy (QFSM) is a live cell imaging method to analyze the dynamics of macromolecular assemblies with high spatial and temporal resolution. Its greatest successes were in the analysis of actin filament and adhesion dynamics in the context of cell migration and microtubule dynamics in interphase and the meotic/mitotic spindle. Here, we focus on the former application to illustrate the procedures of FSM imaging and the computational image processing that extracts quantitative information from these experiments. QFSM is advantageous over other methods because it measures the movement and turnover kinetics of the actin filament (F-actin) network in living cells across the entire field of view. Experiments begin with microinjection of fluorophore-labeled actin into cells, which generate a low ratio of fluorescently-labeled:endogenous unlabeled actin monomers. Spinning disk confocal or wide-field imaging then visualizes fluorophore clusters (2–8 actin monomers) within the assembled F-actin network as speckles. QFSM software identifies and computationally tracks and utilizes the location, appearance, and disappearance of speckles to derive network flows and maps of the rate of filament assembly and disassembly. PMID:23042526

  14. Clinical applications of scanning electron microscopy and X-ray microanalysis in dermatology

    Microsoft Academic Search

    Forslind

    1984-01-01

    Scanning electron microscopy is frequently applied to dermatological problems, as is evident from a review of the recent literature. In this paper, preparation methods and new techniques allowing experimental studies on the integumentary system are emphasized. Quantitative analysis in the electron microscope by use of energy-dispersive X-ray microanalysis (EDX) has become an important accessory technique. EDX can, for instance, be

  15. Scanning electron microscopy studies of bacterial cultures

    NASA Astrophysics Data System (ADS)

    Swinger, Tracy; Blust, Brittni; Calabrese, Joseph; Tzolov, Marian

    2012-02-01

    Scanning electron microscopy is a powerful tool to study the morphology of bacteria. We have used conventional scanning electron microscope to follow the modification of the bacterial morphology over the course of the bacterial growth cycle. The bacteria were fixed in vapors of Glutaraldehyde and ruthenium oxide applied in sequence. A gold film of about 5 nm was deposited on top of the samples to avoid charging and to enhance the contrast. We have selected two types of bacteria Alcaligenes faecalis and Kocuria rhizophila. Their development was carefully monitored and samples were taken for imaging in equal time intervals during their cultivation. These studies are supporting our efforts to develop an optical method for identification of the Gram-type of bacterial cultures.

  16. Trends in low energy electron microscopy

    NASA Astrophysics Data System (ADS)

    Altman, M. S.

    2010-03-01

    Low energy electron microscopy (LEEM) and spin polarized LEEM (SPLEEM) are two powerful in situ techniques for the study of surfaces, thin films and other surface-supported nanostructures. Their real-time imaging and complementary diffraction capabilities allow the study of structure, morphology, magnetism and dynamic processes with high spatial and temporal resolution. Progress in methods, instrumentation and understanding of novel contrast mechanisms that derive from the wave nature and spin degree of freedom of the electron continue to advance applications of LEEM and SPLEEM in these areas and beyond. We review here the basic imaging principles and recent developments that demonstrate the current capabilities of these techniques and suggest potential future directions.

  17. Bright-field quantitative phase microscopy (BFQPM) for accurate phase imaging using conventional microscopy hardware

    NASA Astrophysics Data System (ADS)

    Jenkins, Micah; Gaylord, Thomas K.

    2015-03-01

    Most quantitative phase microscopy methods require the use of custom-built or modified microscopic configurations which are not typically available to most bio/pathologists. There are, however, phase retrieval algorithms which utilize defocused bright-field images as input data and are therefore implementable in existing laboratory environments. Among these, deterministic methods such as those based on inverting the transport-of-intensity equation (TIE) or a phase contrast transfer function (PCTF) are particularly attractive due to their compatibility with Köhler illuminated systems and numerical simplicity. Recently, a new method has been proposed, called multi-filter phase imaging with partially coherent light (MFPI-PC), which alleviates the inherent noise/resolution trade-off in solving the TIE by utilizing a large number of defocused bright-field images spaced equally about the focal plane. Despite greatly improving the state-ofthe- art, the method has many shortcomings including the impracticality of high-speed acquisition, inefficient sampling, and attenuated response at high frequencies due to aperture effects. In this report, we present a new method, called bright-field quantitative phase microscopy (BFQPM), which efficiently utilizes a small number of defocused bright-field images and recovers frequencies out to the partially coherent diffraction limit. The method is based on a noiseminimized inversion of a PCTF derived for each finite defocus distance. We present simulation results which indicate nanoscale optical path length sensitivity and improved performance over MFPI-PC. We also provide experimental results imaging live bovine mesenchymal stem cells at sub-second temporal resolution. In all, BFQPM enables fast and accurate phase imaging with unprecedented spatial resolution using widely available bright-field microscopy hardware.

  18. High resolution scanning electron microscopy of plasmodesmata.

    PubMed

    Brecknock, Sarah; Dibbayawan, Teresa P; Vesk, Maret; Vesk, Peter A; Faulkner, Christine; Barton, Deborah A; Overall, Robyn L

    2011-10-01

    Symplastic transport occurs between neighbouring plant cells through functionally and structurally dynamic channels called plasmodesmata (PD). Relatively little is known about the composition of PD or the mechanisms that facilitate molecular transport into neighbouring cells. While transmission electron microscopy (TEM) provides 2-dimensional information about the structural components of PD, 3-dimensional information is difficult to extract from ultrathin sections. This study has exploited high-resolution scanning electron microscopy (HRSEM) to reveal the 3-dimensional morphology of PD in the cell walls of algae, ferns and higher plants. Varied patterns of PD were observed in the walls, ranging from uniformly distributed individual PD to discrete clusters. Occasionally the thick walls of the giant alga Chara were fractured, revealing the surface morphology of PD within. External structures such as spokes, spirals and mesh were observed surrounding the PD. Enzymatic digestions of cell wall components indicate that cellulose or pectin either compose or stabilise the extracellular spokes. Occasionally, the PD were fractured open and desmotubule-like structures and other particles were observed in their central regions. Our observations add weight to the argument that Chara PD contain desmotubules and are morphologically similar to higher plant PD. PMID:21626150

  19. Transmission Electron Microscopy Characterization of Nanocrystalline Copper

    SciTech Connect

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

    1999-11-01

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

  20. Transmission electron microscopy characterization of nanocrystalline copper

    SciTech Connect

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

    1999-07-01

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

  1. Scanning electron microscopy of tinea nigra*

    PubMed Central

    Guarenti, Isabelle Maffei; de Almeida, Hiram Larangeira; Leitão, Aline Hatzenberger; Rocha, Nara Moreira; Silva, Ricardo Marques e

    2014-01-01

    Tinea nigra is a rare superficial mycosis caused by Hortaea werneckii. This infection presents as asymptomatic brown to black maculae mostly in palmo-plantar regions. We performed scanning electron microscopy of a superficial shaving of a tinea nigra lesion. The examination of the outer surface of the sample showed the epidermis with corneocytes and hyphae and elimination of fungal filaments. The inner surface of the sample showed important aggregation of hyphae among keratinocytes, which formed small fungal colonies. The ultrastructural findings correlated with those of dermoscopic examination - the small fungal aggregations may be the dark spicules seen on dermoscopy - and also allowed to document the mode of dissemination of tinea nigra, showing how hyphae are eliminated on the surface of the lesion. PMID:24770516

  2. Quantitative high dynamic range beam profiling for fluorescence microscopy

    SciTech Connect

    Mitchell, T. J., E-mail: t.j.mitchell@dur.ac.uk; Saunter, C. D.; O’Nions, W.; Girkin, J. M.; Love, G. D. [Centre for Advanced Instrumentation and Biophysical Sciences Institute, Department of Physics, Durham University, Durham DH1 3LE (United Kingdom)

    2014-10-15

    Modern developmental biology relies on optically sectioning fluorescence microscope techniques to produce non-destructive in vivo images of developing specimens at high resolution in three dimensions. As optimal performance of these techniques is reliant on the three-dimensional (3D) intensity profile of the illumination employed, the ability to directly record and analyze these profiles is of great use to the fluorescence microscopist or instrument builder. Though excitation beam profiles can be measured indirectly using a sample of fluorescent beads and recording the emission along the microscope detection path, we demonstrate an alternative approach where a miniature camera sensor is used directly within the illumination beam. Measurements taken using our approach are solely concerned with the illumination optics as the detection optics are not involved. We present a miniature beam profiling device and high dynamic range flux reconstruction algorithm that together are capable of accurately reproducing quantitative 3D flux maps over a large focal volume. Performance of this beam profiling system is verified within an optical test bench and demonstrated for fluorescence microscopy by profiling the low NA illumination beam of a single plane illumination microscope. The generality and success of this approach showcases a widely flexible beam amplitude diagnostic tool for use within the life sciences.

  3. Quantitative polarized light microscopy of unstained mammalian cochlear sections

    NASA Astrophysics Data System (ADS)

    Kalwani, Neil M.; Ong, Cheng Ai; Lysaght, Andrew C.; Haward, Simon J.; McKinley, Gareth H.; Stankovic, Konstantina M.

    2013-02-01

    Hearing loss is the most common sensory deficit in the world, and most frequently it originates in the inner ear. Yet, the inner ear has been difficult to access for diagnosis because of its small size, delicate nature, complex three-dimensional anatomy, and encasement in the densest bone in the body. Evolving optical methods are promising to afford cellular diagnosis of pathologic changes in the inner ear. To appropriately interpret results from these emerging technologies, it is important to characterize optical properties of cochlear tissues. Here, we focus on that characterization using quantitative polarized light microscopy (qPLM) applied to unstained cochlear sections of the mouse, a common animal model of human hearing loss. We find that the most birefringent cochlear materials are collagen fibrils and myelin. Retardance of the otic capsule, the spiral ligament, and the basilar membrane are substantially higher than that of other cochlear structures. Retardance of the spiral ligament and the basilar membrane decrease from the cochlear base to the apex, compared with the more uniform retardance of other structures. The intricate structural details revealed by qPLM of unstained cochlear sections ex vivo strongly motivate future application of polarization-sensitive optical coherence tomography to human cochlea in vivo.

  4. Quantitative polarized light microscopy of unstained mammalian cochlear sections

    PubMed Central

    Kalwani, Neil M.; Ong, Cheng Ai; Lysaght, Andrew C.; Haward, Simon J.; McKinley, Gareth H.; Stankovic, Konstantina M.

    2013-01-01

    Abstract. Hearing loss is the most common sensory deficit in the world, and most frequently it originates in the inner ear. Yet, the inner ear has been difficult to access for diagnosis because of its small size, delicate nature, complex three-dimensional anatomy, and encasement in the densest bone in the body. Evolving optical methods are promising to afford cellular diagnosis of pathologic changes in the inner ear. To appropriately interpret results from these emerging technologies, it is important to characterize optical properties of cochlear tissues. Here, we focus on that characterization using quantitative polarized light microscopy (qPLM) applied to unstained cochlear sections of the mouse, a common animal model of human hearing loss. We find that the most birefringent cochlear materials are collagen fibrils and myelin. Retardance of the otic capsule, the spiral ligament, and the basilar membrane are substantially higher than that of other cochlear structures. Retardance of the spiral ligament and the basilar membrane decrease from the cochlear base to the apex, compared with the more uniform retardance of other structures. The intricate structural details revealed by qPLM of unstained cochlear sections ex vivo strongly motivate future application of polarization-sensitive optical coherence tomography to human cochlea in vivo. PMID:23407909

  5. Silver nanoparticle-induced degranulation observed with quantitative phase microscopy

    NASA Astrophysics Data System (ADS)

    Yang, Wenzhong; Lee, Seungrag; Lee, Jiyong; Bae, Yoonsung; Kim, Dugyoung

    2010-07-01

    Monitoring a degranulation process in a live mast cell is a quite important issue in immunology and pharmacology. Because the size of a granule is normally much smaller than the resolution limit of an optical microscope system, there is no direct real-time live cell imaging technique for observing degranulation processes except for fluorescence imaging techniques. In this research, we propose optical quantitative phase microscopy (QPM) as a new observation tool to study degranulation processes in a live mast cell without any fluorescence labeling. We measure the cell volumes and the cross sectional profiles (x-z plane) of an RBL-2H3 cell and a HeLa cell, before and after they are exposed to calcium ionophore A23187 and silver nanoparticles (AgNPs). We verify that the volume and the cross sectional line profile of the RBL-2H3 cell were changed significantly when it was exposed to A23187. When 50 ?g/mL of AgNP is used instead of A23187, the measurements of cell volume and cross sectional profiles indicate that RBL-2H3 cells also follow degranulation processes. Degranulation processes for these cells are verified by monitoring the increase of intracellular calcium ([Ca2+]i) and histamine with fluorescent methods.

  6. Flash Scanning Electron Microscopy Raphael Sznitman, Aurelien Lucchi, Marco Cantoni,

    E-print Network

    Dalang, Robert C.

    neuroscience has greatly benefited from Scanning Electron Microscope (SEM) technology. With its abilityFlash Scanning Electron Microscopy Raphael Sznitman, Aurelien Lucchi, Marco Cantoni, Graham Knott. Scanning Electron Microscopy (SEM) is an invaluable tool for biologists and neuroscientists to study brain

  7. UNSUPERVISED MORPHOLOGICAL MULTISCALE SEGMENTATION OF SCANNING ELECTRON MICROSCOPY IMAGES

    E-print Network

    Paris-Sud XI, Université de

    A scanning electron microscope (SEM) is a microscope that produces images thanks to a focused beamUNSUPERVISED MORPHOLOGICAL MULTISCALE SEGMENTATION OF SCANNING ELECTRON MICROSCOPY IMAGES Gianni segmentation in the domain of scanning electron microscopy, which is tackled by mathematical morphology

  8. Quantitative nanomechanical measurement of electron beam surface modification

    NASA Astrophysics Data System (ADS)

    Cordes, Aaron; Bunday, Benjamin; Montgomery, Cecilia; Osborne, Jason; Hand, Sean

    2015-03-01

    Electron beam induced surface damage in general, and resist shrinkage in particular, are serious issues in any form of electron beam based metrology. Previous studies investigated dimensional changes that occur in resists that were exposed to electron beams. This work builds on these previous studies to consider changes to the material properties of the exposed resists and other materials using quantitative nano-mechanical mapping scanning probe microscopy. Initial data has shown clearly that there are measurable material differences between pre- and post-electron beam exposure. To study this change iArF photo-resists are exposed to varying electron beam energies and doses. These regions are then measured via SPM for dimensional and material property changes. These changes in the exposed areas are correlated to those predicted by modeled results.

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

    Microsoft Academic Search

    Gangfeng Ye; Jun Nogami; Martin A. Crimp

    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

  10. Reliable strain measurement in transistor arrays by robust scanning transmission electron microscopy

    SciTech Connect

    Kim, Suhyun; Kim, Joong Jung; Jung, Younheum; Lee, Kyungwoo; Byun, Gwangsun; Hwang, KyoungHwan; Lee, Sunyoung; Lee, Kyupil [Memory Analysis Science and Engineering Group, Samsung Electronics, San 16, Hwasung City, Gyeonggi-Do 445-701 (Korea, Republic of)] [Memory Analysis Science and Engineering Group, Samsung Electronics, San 16, Hwasung City, Gyeonggi-Do 445-701 (Korea, Republic of)

    2013-09-15

    Accurate measurement of the strain field in the channels of transistor arrays is critical for strain engineering in modern electronic devices. We applied atomic-resolution high-angle annular dark-field scanning transmission electron microscopy to quantitative measurement of the strain field in transistor arrays. The quantitative strain profile over 20 transistors was obtained with high reliability and a precision of 0.1%. The strain field was found to form homogeneously in the channels of the transistor arrays. Furthermore, strain relaxation due to the thin foil effect was quantitatively investigated for thicknesses of 35 to 275 nm.

  11. Scanning electron microscopy to probe working nanowire gas sensors

    NASA Astrophysics Data System (ADS)

    Liu, Yangmingyue

    This study is dedicated to the implementing of Electron-Beam-Induced Current (EBIC) microscopy to study the behavior of metal oxide semiconducting (MOS) nanowire (NW) gas sensor in situ under exposure to different environment. First, we reported the development of a single nanowire gas sensor compatible with an environmental cell. The major component of the device we use in this study is a single SnO2 nanowire attached to an electron transparent SiN membrane (50-100 nm thick), which was used for mounting nanowire working electrodes and surface imaging of NW. First the NW's conductivity is investigated in different temperatures. Higher temperature is proved to cause higher conductivity of NW. We also found that often the Schottky barrier is formed at the nanowire's contacts with Au and Au/Cr electrodes. Then NW's responses to gas and electron beam (from SEM) are analyzed quantitatively by current measurement. Electron-Beam-Induced Current technique was introduced for the first time to characterize the conductivity behavior of the nanowire during the gas sensing process. Resistive contrast was observed in the EBIC image.

  12. Noninvasive electron microscopy with interaction-free quantum measurements

    E-print Network

    Putnam, William P.

    We propose the use of interaction-free quantum measurements with electrons to eliminate sample damage in electron microscopy. This might allow noninvasive molecular-resolution imaging. We show the possibility of such ...

  13. Fully Hydrated Yeast Cells Imaged with Electron Microscopy

    PubMed Central

    Peckys, Diana B.; Mazur, Peter; Gould, Kathleen L.; de Jonge, Niels

    2011-01-01

    We demonstrate electron microscopy of fully hydrated eukaryotic cells with nanometer resolution. Living Schizosaccaromyces pombe cells were loaded in a microfluidic chamber and imaged in liquid with scanning transmission electron microscopy (STEM). The native intracellular (ultra)structures of wild-type cells and three different mutants were studied without prior labeling, fixation, or staining. The STEM images revealed various intracellular components that were identified on the basis of their shape, size, location, and mass density. The maximal achieved spatial resolution in this initial study was 32 ± 8 nm, an order of magnitude better than achievable with light microscopy on pristine cells. Light-microscopy images of the same samples were correlated with the corresponding electron-microscopy images. Achieving synergy between the capabilities of light and electron microscopy, we anticipate that liquid STEM will be broadly applied to explore the ultrastructure of live cells. PMID:21575587

  14. Transmission electron microscopy on meteoritic troilite

    NASA Astrophysics Data System (ADS)

    Töpel-Schadt, Jutta; Müller, Wolfgang Friedrich

    1982-08-01

    Phase transitions and associated domains of meteoritic troilite (FeS) have been studied by means of transmission electron microscopy (TEM). Three polymorphs have been found, two of which can be described by superstructures of the NiAs-type structure ( A, C subcell). The P overline 6 2c (?3 A, 2 C) polymorph, stable at room temperature, displays antiphase domains with the displacement vector 1/3. In situ heating experiments showed that the P overline 6 2c polymorph changes at temperatures of 115° 150° C into an orthorhombic pseudohexagonal transitional phase with the probable space group Pmcn ( A,?3 A, C). It contains antiphase domains with the displacement vector 1/2 [110] and twins with a threefold twin-axis parallel c. When heated above 210° C the transitional phase transforms into the high-temperature modification with NiAs structure ( P6 3/ mmc). All observed phase transitions are reversible. The occurrence of antiphase and twin domains, respectively, agrees with the symmetry reductions involved in the subsolidus phase transitions. This is demonstrated by group-subgroup relationships among the space groups P6 3/ mmc, Pmcn, and P overline 6 2c.

  15. Imaging Cytoskeleton Components by Electron Microscopy

    PubMed Central

    Svitkina, Tatyana

    2010-01-01

    Summary 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. PMID:19768431

  16. Field Emission Scanning Electron Microscopy (FE-SEM) and Energy Dispersive X-Ray (EDX) Spectroscopy

    E-print Network

    Gelfond, Michael

    system with 30 take-off angle for quantitative analysis, digital imaging, and X-ray mapping. The EDAXField Emission Scanning Electron Microscopy (FE-SEM) and Energy Dispersive X-Ray (EDX) Spectroscopy of objective aperture. Dual SE detectors allow versatile imaging. The FE-SEM is equipped with fully digital

  17. Phase Separation and Atomic Ordering in Epitaxial Semiconductor Alloys Studied by Transmission Electron Microscopy

    Microsoft Academic Search

    Scott Phillip Ahrenkiel

    1995-01-01

    Transmission electron microscopy (TEM) is used to examine the microstructure of epitaxial II-VI and III -V ternary semiconductor alloys. Emphasis is placed on the crystallographic aspects of alloy ordering and phase separation and the influence of growth parameters. Quantitative methods of image and diffraction pattern analysis are examined. TEM studies of novel II-VI pseudobinary alloys grown by molecular beam epitaxy

  18. Detection and comparative analysis of persistent measles virus infection in Crohn's disease by immunogold electron microscopy

    Microsoft Academic Search

    P Daszak; M Purcell; J Lewin; A P Dhillon; R E Pounder; A J Wakefield

    1997-01-01

    AIMS: To determine the specificity of persistent measles virus infection in intestinal samples from Crohn's disease patients using quantitative immunogold electron microscopy. To compare the results with samples from ulcerative colitis, a granulomatous inflammatory control (tuberculous lymphadenitis), and a positive control. METHODS: Formalin fixed, paraffin embedded intestinal tissue from patients with Crohn's disease was reprocessed and stained with antimeasles nucleocaspid

  19. Scanning thermal microscopy of carbon nanotube electronic devices

    Microsoft Academic Search

    Jianhua Zhou; Li Shi

    2005-01-01

    Scanning probe microscopy techniques including scanning gate microscopy (SGM) and scanning thermal microscopy (SThM) have been used to investigate electron transport and energy dissipation mechanisms in single-walled carbon nanotube (CNT) electronic devices. An ultra thin (5-10 nm) layer of polystyrene was coated on the device to protect the CNT devices during thermal imaging. A first harmonic ac measurement SThM method

  20. Plasma Cleaning and Its Applications for Electron Microscopy

    Microsoft Academic Search

    Thomas C. Isabell; Paul E. Fischione; Catherine O'Keefe; Murat U. Guruz; Vinayak P. Dravid

    1999-01-01

    The effectiveness of applying a high-frequency, low-energy, reactive gas plasma for the removal of hydrocarbon contamination from specimens and components for electron microscopy has been investigated with a variety of analytical techniques. Transmission electron microscopy (TEM) analysis of specimens that have been plasma cleaned shows an elimination of the carbonaceous contamination from the specimen. With extended cleaning times the removal

  1. Use of Scanning Electron Microscopy in the Authentication of Botanicals

    Microsoft Academic Search

    Vaishali C. Joshi; Ikhlas A. Khan; Maged H. M. Sharaf

    z ABSTRACT This article provides an overview of scanning electron microscopy and its applications in the identification and authentication of botanicals. The USP Dietary Supplements—Botanicals Expert Committee plans to include scanning electron microscopy as an additional tool in addition to those currently included in USP General Chapter Identification of Articles of Botanical Origin h563i (1). The objectives of this Stimuli

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

    PubMed

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

    2015-01-01

    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. PMID:26066680

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

    PubMed Central

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

    2015-01-01

    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. PMID:26066680

  4. Aberration-Coreected Electron Microscopy at Brookhaven National Laboratory

    SciTech Connect

    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 electron microscopy techniques in strongly correlated electron systems and nanostructured materials. As a first step, with the support of Materials Science Division, Office of Basic Energy Science, US Department of Energy, and the New York State Office of Science, Technology, and Academic Research, recently we acquired three aberration-corrected electron microscopes from the three major microscope manufacturers, i.e., JEOL, Hitachi, and FEI. The Hitachi HD2700C is equipped with a probe corrector, the FEI Titan 80-300 has an imaging corrector, while the JEOL2200MCO has both. All the correctors are of the dual-hexapole type, designed and manufactured by CEOS GmbH based on the design due to Rose and Haider [3, 18]. All these three are one-of-a-kind in the US, designed for specialized capabilities in characterizing nanoscale structure. In this chapter, we review the performance of these state-of-the art instruments and the new challenges associated with the improved spatial resolution, including the environment requirements of the laboratory that hosts these instruments. Although each instrument we describe here has its own strengths and drawbacks, it is not our intention to rank them in terms of their performance, especially their spatial resolution in imaging.

  5. Use of digital micromirror devices in quantitative microscopy

    Microsoft Academic Search

    Calum E. Macaulay; Andrew Dlugan

    1998-01-01

    There are numerous modes of microscopy such as brightfield, darkfield, phase contrast, fluorescence, reflected light, confocal, etc. All of these forms of microscopy deliver illumination light in a controlled fashion to the object to be examined and collect as much light containing the desired information as possible. The majority of these methods use appropriately placed and formed diaphragms (iris, pin

  6. Quantitative live cell fluorescence-microscopy analysis of fission yeast.

    PubMed

    Bjerling, Pernilla; Olsson, Ida; Meng, Xi'nan

    2012-01-01

    Several microscopy techniques are available today that can detect a specific protein within the cell. During the last decade live cell imaging using fluorochromes like Green Fluorescent Protein (GFP) directly attached to the protein of interest has become increasingly popular. Using GFP and similar fluorochromes the subcellular localisations and movements of proteins can be detected in a fluorescent microscope. Moreover, also the subnuclear localisation of a certain region of a chromosome can be studied using this technique. GFP is fused to the Lac Repressor protein (LacR) and ectopically expressed in the cell where tandem repeats of the lacO sequence has been inserted into the region of interest on the chromosome. The LacR-GFP will bind to the lacO repeats and that area of the genome will be visible as a green dot in the fluorescence microscope. Yeast is especially suited for this type of manipulation since homologous recombination is very efficient and thereby enables targeted integration of the lacO repeats and engineered fusion proteins with GFP. Here we describe a quantitative method for live cell analysis of fission yeast. Additional protocols for live cell analysis of fission yeast can be found, for example on how to make a movie of the meiotic chromosomal behaviour. In this particular experiment we focus on subnuclear organisation and how it is affected during gene induction. We have labelled a gene cluster, named Chr1, by the introduction of lacO binding sites in the vicinity of the genes. The gene cluster is enriched for genes that are induced early during nitrogen starvation of fission yeast. In the strain the nuclear membrane (NM) is labelled by the attachment of mCherry to the NM protein Cut11 giving rise to a red fluorescent signal. The Spindle Pole body (SPB) compound Sid4 is fused to Red Fluorescent Protein (Sid4-mRFP). In vegetatively growing yeast cells the centromeres are always attached to the SPB that is embedded in the NM. The SPB is identified as a large round structure in the NM. By imaging before and 20 minutes after depletion of the nitrogen source we can determine the distance between the gene cluster (GFP) and the NM/SPB. The mean or median distances before and after nitrogen depletion are compared and we can thus quantify whether or not there is a shift in subcellular localisation of the gene cluster after nitrogen depletion. PMID:22297579

  7. Correlative light and volume electron microscopy: using focused ion beam scanning electron microscopy to image transient events in model organisms.

    PubMed

    Bushby, Andrew J; Mariggi, Giovanni; Armer, Hannah E J; Collinson, Lucy M

    2012-01-01

    The study of a biological event within a live model organism has become routine through the use of fluorescent labeling of specific proteins in conjunction with laser confocal imaging. These methods allow 3D visualization of temporal events that can elucidate biological function but cannot resolve the tissue organization, extracellular and subcellular details of the tissues. Here, we present a method for correlating electron microscopy image data with the light microscopy data from the same sample volume to reveal the 3D structural information: "correlative light and volume electron microscopy." The methods for live video confocal microscopy, fixation and embedding of the tissue for electron microscopy, the focused ion beam scanning electron microscopy method for sequentially slicing and imaging the volume of interest, and the treatment of the resulting 3D dataset are presented. The method is illustrated with data collected during the angiogenesis of blood vessels in a transgenic zebrafish embryo. PMID:22857937

  8. Silicon nitride windows for electron microscopy of whole cells.

    PubMed

    Ring, E A; Peckys, D B; Dukes, M J; Baudoin, J P; de Jonge, N

    2011-09-01

    Silicon microchips with thin, electron transparent silicon nitride windows provide a sample support that accommodates both light-, and electron microscopy of whole eukaryotic cells in vacuum or liquid, with minimum sample preparation steps. The windows are robust enough that cellular samples can be cultured directly onto them, with no addition of a supporting film, and there is no need to embed or section the sample, as is typically required in electron microscopy. By combining two microchips, a microfluidic chamber can be constructed for the imaging of samples in liquid in the electron microscope. We provide microchip design specifications, a fabrication outline, instructions on how to prepare the microchips for biological samples, and examples of images obtained using different light and electron microscopy modalities. The use of these microchips is particularly advantageous for correlative light and electron microscopy. PMID:21770941

  9. Silicon Nitride Windows for Electron Microscopy of Whole Cells

    PubMed Central

    Ring, E. A.; Peckys, D. B.; Dukes, M. J.; Baudoin, J. P.; de Jonge, N.

    2012-01-01

    Summary Silicon microchips with thin electron transparent silicon nitride windows provide a sample support that accommodates both light-, and electron microscopy of whole eukaryotic cells in vacuum or liquid, with minimum sample preparation steps. The windows are robust enough that cellular samples can be cultured directly onto them, with no addition of a supporting film, and no need to embed or section the sample, as is typically required in electron microscopy. By combining two microchips, a microfluidic chamber can be constructed for the imaging of samples in liquid in the electron microscope. We provide microchip design specifications, a fabrication outline, instructions on how to prepare them for biological samples, and examples of images obtained using different light-, and electron microscopy modalities. The use of these microchips is particularly advantageous for correlative light-, and electron microscopy. PMID:21770941

  10. Spectral-domain optical coherence phase microscopy for quantitative biological studies

    E-print Network

    Joo, Chulmin, 1976-

    2008-01-01

    Conventional phase-contrast and differential interference contrast microscopy produce high contrast images of transparent specimens such as cells. However, they do not provide quantitative information or do not have enough ...

  11. ADVANCED ELECTRON MICROSCOPY AND MATERIALS PHYSICS WORKSHOP

    E-print Network

    Johnson, Peter D.

    Practical Aspects of Atomic-Column Imaging Using ADF and EELS 2:30 - Nigel Browning (UC-Davis) - Imaging and the Current Development on Structure Reversion 4:30 - Rudolf Tromp (IBM) - Cathode Lens Microscopy: The Next

  12. Characterization of Polymeric Particles with Electron Microscopy, Dynamic Light Scattering, and Atomic Force Microscopy

    Microsoft Academic Search

    Betina Giehl Zanetti-Ramos; Mauricia Beddin Fritzen-Garcia; Tânia Beatriz Creczynski-Pasa; Cristian Schweitzer De Oliveira; André Avelino Pasa; Valdir Soldi; Redouane Borsali

    2010-01-01

    The purpose of this article is to describe the use of different techniques, such as dynamic light scattering (DLS), electron microscopy (EM), and atomic force microscopy (AFM), on the characterization of particulate systems. A brief theoretical introduction for each technique is presented, including advantages and disadvantages. Micro- and nanoparticles of polyurethane were used as examples to illustrate the use of

  13. Advanced Correlative Light/Electron Microscopy: Current Methods and New Developments Using Tokuyasu Cryosections

    PubMed Central

    Cortese, Katia; Diaspro, Alberto; Tacchetti, Carlo

    2009-01-01

    Microscopy is an essential tool for analysis of cellular structures and function. With the advent of new fluorescent probes and super-resolution light microscopy techniques, the study of dynamic processes in living cells has been greatly facilitated. Fluorescence light microscopy provides analytical, quantitative, and three-dimensional (3D) data with emphasis on analysis of live cells using fluorescent markers. Sample preparation is easy and relatively inexpensive, and the use of appropriate tags provides the ability to track specific proteins of interest. Of course, only electron microscopy (EM) achieves the highest definition in terms of ultrastructure and protein labeling. To fill the gap between light microscopy and EM, correlative light and electron microscopy (CLEM) strategies have been developed. In particular, hybrid techniques based upon immuno-EM provide sensitive protein detection combined with high-resolution information on cell structures and protein localization. By adding the third dimension to EM with electron tomography (ET) combined with rapid freezing, CLEM techniques now provide additional tools for quantitative 3D analysis. Here, we overview the major methods applied and highlight the latest advances in the field of CLEM. We then focus on two selected techniques that use cryosections as substrate for combined biomolecular imaging. Finally, we provide a perspective of future developments in the field. (J Histochem Cytochem 57:1103–1112, 2009) PMID:19654103

  14. Advanced correlative light/electron microscopy: current methods and new developments using Tokuyasu cryosections.

    PubMed

    Cortese, Katia; Diaspro, Alberto; Tacchetti, Carlo

    2009-12-01

    Microscopy is an essential tool for analysis of cellular structures and function. With the advent of new fluorescent probes and super-resolution light microscopy techniques, the study of dynamic processes in living cells has been greatly facilitated. Fluorescence light microscopy provides analytical, quantitative, and three-dimensional (3D) data with emphasis on analysis of live cells using fluorescent markers. Sample preparation is easy and relatively inexpensive, and the use of appropriate tags provides the ability to track specific proteins of interest. Of course, only electron microscopy (EM) achieves the highest definition in terms of ultrastructure and protein labeling. To fill the gap between light microscopy and EM, correlative light and electron microscopy (CLEM) strategies have been developed. In particular, hybrid techniques based upon immuno-EM provide sensitive protein detection combined with high-resolution information on cell structures and protein localization. By adding the third dimension to EM with electron tomography (ET) combined with rapid freezing, CLEM techniques now provide additional tools for quantitative 3D analysis. Here, we overview the major methods applied and highlight the latest advances in the field of CLEM. We then focus on two selected techniques that use cryosections as substrate for combined biomolecular imaging. Finally, we provide a perspective of future developments in the field. PMID:19654103

  15. Quantitative microscopy reveals 3D organization and kinetics of endocytosis in rat hepatocytes.

    PubMed

    Marbet, Permsin; Rahner, Christoph; Stieger, Bruno; Landmann, Lukas

    2006-09-01

    In order to demonstrate the power of quantitative microscopy, the endocytic apparatus of rat hepatocytes was reexamined using in situ liver and short term cultured hepatocyte couplets that were allowed to internalize endocytic markers for various time intervals. Correlative confocal light and electron microscopy demonstrate a tubulovesicular reticulum representing the endocytic apparatus. Volume and membrane area account for 2% of cell volume and 30% plasma membrane surface. Colocalization analysis demonstrated that pathway-specific ligands and fluid-phase markers enter EEA1-positive vesicles, the early endosomal compartment, immediately after internalization. These vesicles are translocated rapidly from basolateral to perinuclear and apical locations. Ligands are sorted within 5 min to their respective pathways. Sequential colocalization of an asialoglycoprotein-pulse with rab7 and lamp3 demonstrates that early endosomes change into or fuse with late endosomes and lysosomes. Alternatively, markers are sequestered into the common endosome consisting of rab11-positive, long tubules that originate from early endosomes and show an affinity for the transcytotic marker pIgA and its receptor. This compartment mediates transcytosis by delivering the receptor-ligand complex to the subapical compartment, a set of apical, rab11-positive vesicles, which are connected to the tubular reticulum. We conclude that vesicular traffic between preexisting compartments, maturation or fusion of endocytic organelles, and transport in tubules act in concert and together mediate transport between compartments of a tubulovesicular endocytic apparatus. In addition, we show that quantitative microscopy using high resolution data sets can detect and characterize kinetics of various parameters thus adding a dynamic component to 3D information. PMID:16886231

  16. Novel Application of Fluorescence Lifetime and Fluorescence Microscopy Enables Quantitative Access to Subcellular Dynamics in Plant Cells

    PubMed Central

    Elgass, Kirstin; Caesar, Katharina; Schleifenbaum, Frank; Stierhof, York-Dieter; Meixner, Alfred J.; Harter, Klaus

    2009-01-01

    Background Optical and spectroscopic technologies working at subcellular resolution with quantitative output are required for a deeper understanding of molecular processes and mechanisms in living cells. Such technologies are prerequisite for the realisation of predictive biology at cellular and subcellular level. However, although established in the physical sciences, these techniques are rarely applied to cell biology in the plant sciences. Principal Findings Here, we present a combined application of one-chromophore fluorescence lifetime microscopy and wavelength-selective fluorescence microscopy to analyse the function of a GFP fusion of the Brassinosteroid Insensitive 1 Receptor (BRI1-GFP) with high spatial and temporal resolution in living Arabidopsis cells in their tissue environment. We show a rapid, brassinolide-induced cell wall expansion and a fast BR-regulated change in the BRI1-GFP fluorescence lifetime in the plasmamembrane in vivo. Both cell wall expansion and changes in fluorescence lifetime reflect early BR-induced and BRI1-dependent physiological or signalling processes. Our experiments also show the potential of one-chromophore fluorescence lifetime microscopy for the in vivo monitoring of the biochemical and biophysical subcellular environment using GFP fusion proteins as probes. Significance One-chromophore fluorescence lifetime microscopy, combined with wavelength-specific fluorescence microscopy, opens up new frontiers for in vivo dynamic and quantitative analysis of cellular processes at high resolution which are not addressable by pure imaging technologies or transmission electron microscopy. PMID:19492078

  17. Quantitative Electron Diffraction Structure Analysis (EDSA)

    Microsoft Academic Search

    A. S. Avilov

    The modern state of EDSA in combination with topological analysis of the ESP and electron density allows to obtain reliable\\u000a and quantitative information about chemical bonding and properties.\\u000a \\u000a The electrostatic field in a crystal is good characterized, the determining factor is however, the introduction of cations\\u000a in the ESP of NaCl type structures. Thus precise EDSA data for calculating the

  18. Modern uses of electron microscopy for detection of viruses.

    PubMed

    Goldsmith, Cynthia S; Miller, Sara E

    2009-10-01

    Electron microscopy, considered by some to be an old technique, is still on the forefront of both clinical viral diagnoses and viral ultrastructure and pathogenesis studies. In the diagnostic setting, it is particularly valuable in the surveillance of emerging diseases and potential bioterrorism viruses. In the research arena, modalities such as immunoelectron microscopy, cryo-electron microscopy, and electron tomography have demonstrated how viral structural components fit together, attach to cells, assimilate during replication, and associate with the cellular machinery during replication and egression. These studies provide information for treatment and vaccine strategies. PMID:19822888

  19. Electron microscopy study of zeolite ZK-14; a synthetic chabazite

    NASA Astrophysics Data System (ADS)

    Cartlidge, S.; Wessicken, R.; Nissen, H.-U.

    1983-03-01

    The defect structure of zeolite (K+, TMA+) — ZK-14, a synthetic chabazite, has been studied using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). SEM together with TEM bright field (BF) and dark field (DF) micrographs indicate that the hexagonal, platelet ZK-14 crystals are built up of crystalline blocks joined by twinning along (00.1). High resolution transmission electron microscopy (HRTEM) reveals faulting of the ideal AABBCC single 6-ring stacking sequence of ZK-14. This is consistent with an observed line broadening in its X-ray powder diffraction profile. Channel apertures are imaged, even for thick specimens.

  20. Quantitative laser scanning confocal autofluorescence microscopy of normal, premalignant, and malignant colonic tissues

    Microsoft Academic Search

    Hsing-Wen Wang; Joseph Willis; Marcia I. F. Canto; Michael V. Sivak; Joseph A. Izatt

    1999-01-01

    Laser scanning confocal autofluorescence microscopy (LSCAM) using 351- to 364-nm excitation light was used to quantitatively compare fluorescent spectral emission of unstained, frozen histological sections of normal, premalignant, and malignant colonic tissues. To identify the spatial origins of fluorescent signals accurately, the same frozen section slides used for microscopy were fixed and histochemically stained immediately following LSCAM imaging. Tissue fluorescence

  1. High voltage electron microscopy and low voltage scanning electron microscopy of human neoplastic cell culture.

    PubMed

    Malecki, M

    1991-01-01

    Improved procedures were developed to correlate cell culture data with the images provided by advanced ultrastructural technologies. These procedures were compatible with the two main types of cellular behavior: adherent, spreading (melanomas, rhabdomyosarcomas) and non-adherent in suspension (leukemias). The ultrastructure and function of spreading neoplastic cells primarily depend on surface properties of the attaching substrates. Therefore, the films used for cultured cell whole-mount ultrastructural analysis must have adherence features identical to those of standard cell culture vessels. Improved procedures were developed to produce the polystyrene films of required qualities. These films allowed processing of cells for electron microscopy including chemical fixation, cryo-immobilization, and immunolabelling. Furthermore, these polystyrene films permitted observations of the same cell in the high voltage electron microscope to reveal the internal organization and in the low voltage scanning electron microscope to reveal the surface topography. Neoplastic cells in suspension may dramatically change their ultrastructure as a result of interactions with substrates or other cells. Therefore, immobilization of cellular processes must occur rapidly while cells remain in suspension. These processes were cryo-immobilized by high pressure freezing through the use of the newly designed specimen carrier. Procedures allowing high yield attachment of cryo-fixed neoplastic cells to amino-propyl-derived glass carriers enabled observations of cell surface topography. Furthermore, freeze-substitution and drying of freeze-fractured cells revealed their three-dimensional internal organization in the low voltage scanning electron microscope. PMID:1822024

  2. Correlative light and electron microscopy using immunolabeled sections.

    PubMed

    Schwarz, Heinz; Humbel, Bruno M

    2014-01-01

    In correlative microscopy, light microscopy provides the overview and orientation of the complex cells and tissue, while electron microscopy offers the detailed localization and correlation of subcellular structures. In this chapter we offer detailed high-quality electron microscopical preparation methods for optimum preservation of the cellular ultrastructure. From such preparations serial thin sections are collected and used for comparative histochemical, immunofluorescence, and immunogold staining.In light microscopy histological stains identify the orientation of the sample and immunofluorescence labeling facilitates to find the region of interest, namely, the labeled cells expressing the macromolecule under investigation. Sections, labeled with immunogold are analyzed by electron microscopy in order to identify the label within the cellular architecture at high resolution. PMID:24357380

  3. Sub-Nanometer Au Monolayer-Protected Clusters Exhibiting Molecule-like Electronic Behavior: Quantitative High-Angle Annular Dark-Field Scanning Transmission Electron

    E-print Network

    Frenkel, Anatoly

    : Quantitative High-Angle Annular Dark-Field Scanning Transmission Electron Microscopy and Electrochemical of the number of gold atoms in the cluster cores using high- angle annular dark-field scanning transmission

  4. In Situ Analytical Electron Microscopy for Probing Nanoscale Electrochemistry

    SciTech Connect

    Graetz J.; Meng, Y.S.; McGilvray, T.; Yang, M.-C.; Gostovic, D.; Wang, F.; Zeng, D.; Zhu, Y.

    2011-10-31

    Oxides and their tailored structures are at the heart of electrochemical energy storage technologies and advances in understanding and controlling the dynamic behaviors in the complex oxides, particularly at the interfaces, during electrochemical processes will catalyze creative design concepts for new materials with enhanced and better-understood properties. Such knowledge is not accessible without new analytical tools. New innovative experimental techniques are needed for understanding the chemistry and structure of the bulk and interfaces, more importantly how they change with electrochemical processes in situ. Analytical Transmission Electron Microscopy (TEM) is used extensively to study electrode materials ex situ and is one of the most powerful tools to obtain structural, morphological, and compositional information at nanometer scale by combining imaging, diffraction and spectroscopy, e.g., EDS (energy dispersive X-ray spectrometry) and Electron Energy Loss Spectrometry (EELS). Determining the composition/structure evolution upon electrochemical cycling at the bulk and interfaces can be addressed by new electron microscopy technique with which one can observe, at the nanometer scale and in situ, the dynamic phenomena in the electrode materials. In electrochemical systems, for instance in a lithium ion battery (LIB), materials operate under conditions that are far from equilibrium, so that the materials studied ex situ may not capture the processes that occur in situ in a working battery. In situ electrochemical operation in the ultra-high vacuum column of a TEM has been pursued by two major strategies. In one strategy, a 'nano-battery' can be fabricated from an all-solid-state thin film battery using a focused ion beam (FIB). The electrolyte is either polymer based or ceramic based without any liquid component. As shown in Fig. 1a, the interfaces between the active electrode material/electrolyte can be clearly observed with TEM imaging, in contrast to the composite electrodes/electrolyte interfaces in conventional lithium ion batteries, depicted in Fig.1b, where quantitative interface characterization is extremely difficult if not impossible. A second strategy involves organic electrolyte, though this approach more closely resembles the actual operation conditions of a LIB, the extreme volatility In Situ Analytical Electron Microscopy for Probing Nanoscale Electrochemistry by Ying Shirley Meng, Thomas McGilvray, Ming-Che Yang, Danijel Gostovic, Feng Wang, Dongli Zeng, Yimei Zhu, and Jason Graetz of the organic electrolytes present significant challenges for designing an in situ cell that is suitable for the vacuum environment of the TEM. Significant progress has been made in the past few years on the development of in situ electron microscopy for probing nanoscale electrochemistry. In 2008, Brazier et al. reported the first cross-section observation of an all solid-state lithium ion nano-battery by TEM. In this study the FIB was used to make a 'nano-battery,' from an all solid-state battery prepared by pulsed laser deposition (PLD). In situ TEM observations were not possible at that time due to several key challenges such as the lack of a suitable biasing sample holder and vacuum transfer of sample. In 2010, Yamamoto et al. successfully observed changes of electric potential in an all-solid-state lithium ion battery in situ with electron holography (EH). The 2D potential distribution resulting from movement of lithium ions near the positive-electrode/electrolyte interface was quantified. More recently Huang et al. and Wang et al. reported the in situ observations of the electrochemical lithiation of a single SnO{sub 2} nanowire electrode in two different in situ setups. In their approach, a vacuum compatible ionic liquid is used as the electrolyte, eliminating the need for complicated membrane sealing to prevent the evaporation of carbonate based organic electrolyte into the TEM column. One main limitation of this approach is that EELS spectral imaging is not possible due to the high plasmon signal of the ionic li

  5. Serial Block-Face Scanning Electron Microscopy to Reconstruct

    E-print Network

    Born, Richard

    of a scanning electron microscope. Backscattering contrast is used to visualize the heavy-metal stainingSerial Block-Face Scanning Electron Microscopy to Reconstruct Three-Dimensional Tissue at electron microscopic, and tissue at light-microscopic resolution. A gap exists, however, when 3D tissue

  6. APPLICATIONS OF PLASMA CLEANING FOR ELECTRON MICROSCOPY OF SEMICONDUCTING MATERIALS

    Microsoft Academic Search

    T. C. ISABELL; P. E. FISCHIONE

    As semiconductor device sizes continue to decrease, the degree of accuracy needed for electron microscopy and microanalyis of such materials increases. To achieve such accuracy, small electron probes with high beam currents are needed. The combination of these two factors results in an increase in the amount of carbonaceous contamination formed on the specimen under the electron beam. Recently, the

  7. Advanced fertility diagnosis in stallion semen using transmission electron microscopy

    Microsoft Academic Search

    Sandra Pesch; Hartwig Bostedt; Klaus Failing; Martin Bergmann

    2006-01-01

    Routine semen analysis of stallions is based on light microscopy (LM). However, there are still a number of animals that are subfertile or even infertile not being identified with conventional semen analysis. The objective of this study was to investigate the suitability of transmission electron microscopy (TEM) for advanced fertility diagnosis in stallion. We examined ejaculates of 46 stallions with

  8. Carbon nanomaterial studied by atomic-force and electron microscopies

    SciTech Connect

    Bobrinetski, I. I.; Kukin, V. N.; Nevolin, V. K., E-mail: vkn@miee.ru; Simunin, M. M. [Moscow State Institute of Electronics (Technical University) (Russian Federation)

    2008-12-15

    It is suggested to use the atomic-force microscopy (AFM) and transmission electron microscopy (TEM) to study carbon material synthesized by catalytic pyrolysis of ethanol. It is shown how AFM and TEM can be employed to determine the geometric parameters of carbon nanofibers and nanotubes, examine their mechanical and adhesion characteristics, and analyze their structure.

  9. Scanning electron microscopy of acantholysis in pemphigus foliaceus*

    PubMed Central

    de Almeida, Hiram Larangeira; Leitão, Aline Hatzenberger; Rossi, Gabriela; Rocha, Nara Moreira; Silva, Ricardo Marques e

    2013-01-01

    We performed scanning electron microscopy of an inverted blister roof in a case of pemphigus foliaceus. The loss of intercellular adherence could be easily seen with low magnification. The acantholytic keratinocytes displayed an irregular and sometimes polygonal contour. Round cells, typically seen in light microscopy, were also observed. The examination of a blister roof allows ultrastructural documentation of the acantholytic changes. PMID:23793219

  10. Advances in the Transmission Electron Microscopy of Polymers

    Microsoft Academic Search

    Matthew R. Libera; Ray F. Egerton

    2010-01-01

    Transmission electron microscopy (TEM) of polymers involves the problem definition and methodologies associated with the microscopy of both inorganic and biological materials but cannot be categorized within either of these fields alone. On the one hand, like other synthetic materials, polymers offer the ability to control properties through synthesis and processing, and TEM is a powerful method with which to

  11. The use of markers for correlative light electron microscopy.

    PubMed

    Brown, Edward; Verkade, Paul

    2010-08-01

    Bioimaging: the visualisation, localisation and tracking of movement of specific molecules in cells using microscopy has become an increasing field of interest within life science research. For this, the availability of fluorescent and electron-dense markers for light and electron microscopy, respectively, is an essential tool to attach to the molecules of interest. In recent years, there has been an increasing effort to combine light and electron microscopy in a single experiment. Such correlative light electron microscopy (CLEM) experiments thus rely on using markers that are both fluorescent and electron dense. Unfortunately, there are very few markers that possess both these properties. Markers for light microscopy such as green fluorescent protein are generally not directly visible in the electron microscopy and vice versa for gold particles. Hence, there has been an intensive search for markers that are directly visible both in the light microscope and in the electron microscope. Here we discuss some of the strategies and pitfalls that are associated with the use of CLEM markers, which might serve as a "warning" that new probes should be extensively tested before use. We focus on the use of CLEM markers for the study of intracellular transport and specifically endocytosis. PMID:20524017

  12. Quantitative force measurements with intermodulation atomic force microscopy

    Microsoft Academic Search

    Daniel Platz; Daniel Forchheimer; Carsten Hutter; Erik Tholén; David Haviland

    2011-01-01

    Dynamic atomic force microscopy (dynamic AFM) is a key tool for surface characterization on the nanoscale. Operation close to a cantilever resonance increases sensitivity and allows for the measurement of the phase of the cantilever response. This phase is traditionally interpreted as a measure of the energy dissipation due to the tip-sample interaction. However, a full understanding of dissipative processes

  13. Quantitative determination of tip parameters in piezoresponse force microscopy

    E-print Network

    Gopalan, Venkatraman

    microscopy PFM is the lack of knowledge on the effective tip geometry. Here the authors derive analytical expressions for a 180° domain wall profile in PFM for the point charge, sphere plane, and disk electrode can be used self-consistently for the interpretation of PFM resolution and spectroscopy data, i

  14. Quantitative DIC Microscopy: Improving Versatility for Live-Cell Imaging

    Microsoft Academic Search

    Carol J. Cogswell; Sharon V. King; Ariel Libertun; Rafael Piestun; Chrysanthe Preza

    2004-01-01

    Our ongoing investigations of DIC microscopy have shown it is possible to measure phase variations by using calibration standards and correlating them to actual thickness or refractive index variations within an object. In biological applications, this can provide an alternative modality to fluorescence for imaging and tracking live-cell dynamics, with the advantage that lower intensity illumination can be used and

  15. Outcome of the first electron microscopy validation task force meeting.

    PubMed

    Henderson, Richard; Sali, Andrej; Baker, Matthew L; Carragher, Bridget; Devkota, Batsal; Downing, Kenneth H; Egelman, Edward H; Feng, Zukang; Frank, Joachim; Grigorieff, Nikolaus; Jiang, Wen; Ludtke, Steven J; Medalia, Ohad; Penczek, Pawel A; Rosenthal, Peter B; Rossmann, Michael G; Schmid, Michael F; Schröder, Gunnar F; Steven, Alasdair C; Stokes, David L; Westbrook, John D; Wriggers, Willy; Yang, Huanwang; Young, Jasmine; Berman, Helen M; Chiu, Wah; Kleywegt, Gerard J; Lawson, Catherine L

    2012-02-01

    This Meeting Review describes the proceedings and conclusions from the inaugural meeting of the Electron Microscopy Validation Task Force organized by the Unified Data Resource for 3DEM (http://www.emdatabank.org) and held at Rutgers University in New Brunswick, NJ on September 28 and 29, 2010. At the workshop, a group of scientists involved in collecting electron microscopy data, using the data to determine three-dimensional electron microscopy (3DEM) density maps, and building molecular models into the maps explored how to assess maps, models, and other data that are deposited into the Electron Microscopy Data Bank and Protein Data Bank public data archives. The specific recommendations resulting from the workshop aim to increase the impact of 3DEM in biology and medicine. PMID:22325770

  16. TRANSMISSION ELECTRON MICROSCOPY OF WEAKLY DEFORMED ALKALI HALIDE CRYSTALS

    E-print Network

    Boyer, Edmond

    377 TRANSMISSION ELECTRON MICROSCOPY OF WEAKLY DEFORMED ALKALI HALIDE CRYSTALS H. STRUNK Max) is applied to the investigation of the dis- location arrangement of [001]-orientated alkali halide crystals

  17. Electron Microscopy DOI: 10.1002/anie.200604811

    E-print Network

    Dunin-Borkowski, Rafal E.

    , respec- tively, of a polymer electrolyte membrane fuel cell. Figure 1A shows the measured phase of ammonia synthesis in a Ru-catalyzed reaction.[1] High-resolution trans- mission electron microscopy (HRTEM

  18. Axon Tracking in Serial Block-Face Scanning Electron Microscopy

    Microsoft Academic Search

    Elizabeth Jurrus; Tolga Tasdizen; Pavel Koshevoy; P. Thomas Fletcher; Melissa Hardy; Chi-Bin Chien; Winfried Denk; Ross Whitaker

    2006-01-01

    Electron microscopy is an important modality for the analysis of neuronal structures in neurobiology. We address the problem of tracking axons across large distances in volumes acquired by Serial Block-Face Scanning Electron Microscopy (SBFSEM). This is a challenging problem due to the small cross- sectional size of axons and the low signal-to-noise ratio in SBF- SEM images. A carefully engineered

  19. Structured illumination quantitative phase microscopy for enhanced resolution amplitude and phase imaging

    PubMed Central

    Chowdhury, Shwetadwip; Izatt, Joseph

    2013-01-01

    Structured illumination microscopy (SIM) is an established microscopy technique typically used to image samples at resolutions beyond the diffraction limit. Until now, however, achieving sub-diffraction resolution has predominantly been limited to intensity-based imaging modalities. Here, we introduce an analogue to conventional SIM that allows sub-diffraction resolution, quantitative phase-contrast imaging of optically transparent objects. We demonstrate sub-diffraction resolution amplitude and quantitative-phase imaging of phantom targets and enhanced resolution quantitative-phase imaging of cells. We report a phase accuracy to within 5% and phase noise of 0.06 rad. PMID:24156044

  20. Ion-induced electron emission microscopy

    DOEpatents

    Doyle, Barney L. (Albuquerque, NM); Vizkelethy, Gyorgy (Albuquerque, NM); Weller, Robert A. (Brentwood, TN)

    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.

  1. Analytical electron microscopy of aluminium alloys

    Microsoft Academic Search

    T R Ramachandran; D C Houghton; J D Embury

    1984-01-01

    X-ray microanalysis and electron energy loss spectroscopy of thin foils constitute the important techniques of high resolution\\u000a chemical analysis using the electron microscope. The technique of x-ray microanalysis is discussed in this paper with particular\\u000a emphasis on the study of aluminium alloys using a dedicated scanning transmission electron microscope (stem).\\u000a \\u000a The principle of determining chemical composition from observed x-ray peak

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

    PubMed

    Peddie, Christopher J; Collinson, Lucy M

    2014-06-01

    Groundbreaking advances in volume electron microscopy and specimen preparation are enabling the 3-dimensional visualisation of specimens with unprecedented detail, and driving a gratifying resurgence of interest in the ultrastructural examination of cellular systems. Serial section techniques, previously the domain of specialists, are becoming increasingly automated with the development of systems such as the automatic tape-collecting ultramicrotome, and serial blockface and focused ion beam scanning electron microscopes. These changes are rapidly broadening the scope of biomedical studies to which volume electron microscopy techniques can be applied beyond the brain. Further innovations in microscope design are also in the pipeline, which have the potential to enhance the speed and quality of data collection. The recent introduction of integrated light and electron microscopy systems will revolutionise correlative light and volume electron microscopy studies, by enabling the sequential collection of data from light and electron imaging modalities without intermediate specimen manipulation. In doing so, the acquisition of comprehensive functional information and direct correlation with ultrastructural details within a 3-dimensional reference space will become routine. The prospects for volume electron microscopy are therefore bright, and the stage is set for a challenging and exciting future. PMID:24792442

  3. Preparation of Xenopus laevis retinal cryosections for electron microscopy.

    PubMed

    Tam, Beatrice M; Yang, Lee Ling; Bog?a, Tami H; Ross, Bradford; Martens, Garnet; Moritz, Orson L

    2015-07-01

    Transmission electron microscopy is the gold standard for examination of photoreceptor outer segment morphology and photoreceptor outer segment abnormalities in transgenic animal models of retinal disease. Small vertebrates such as zebrafish and Xenopus laevis tadpoles have been used to generate retinal disease models and to study outer segment processes such as protein trafficking, and their breeding capabilities facilitate experiments involving large numbers of animals and conditions. However, electron microscopy processing and analysis of these very small eyes can be challenging. Here we present a methodology that facilitates processing of X. laevis tadpole eyes for electron microscopy by introducing an intermediate cryosectioning step. This method reproducibly provides a well-oriented tissue block that can be sectioned with minimal effort by a non-expert, and also allows retroactive analysis of samples collected on slides for light microscopy. PMID:26008144

  4. The CryoCapsule: simplifying correlative light to electron microscopy.

    PubMed

    Heiligenstein, Xavier; Heiligenstein, Jérôme; Delevoye, Cédric; Hurbain, Ilse; Bardin, Sabine; Paul-Gilloteaux, Perrine; Sengmanivong, Lucie; Régnier, Gilles; Salamero, Jean; Antony, Claude; Raposo, Graca

    2014-06-01

    Correlating complementary multiple scale images of the same object is a straightforward means to decipher biological processes. Light microscopy and electron microscopy are the most commonly used imaging techniques, yet despite their complementarity, the experimental procedures available to correlate them are technically complex. We designed and manufactured a new device adapted to many biological specimens, the CryoCapsule, that simplifies the multiple sample preparation steps, which at present separate live cell fluorescence imaging from contextual high-resolution electron microscopy, thus opening new strategies for full correlative light to electron microscopy. We tested the biological application of this highly optimized tool on three different specimens: the in vitro Xenopus laevis mitotic spindle, melanoma cells over-expressing YFP-langerin sequestered in organized membranous subcellular organelles and a pigmented melanocytic cell in which the endosomal system was labeled with internalized fluorescent transferrin. PMID:24533564

  5. Multimodal dyes: toward correlative two-photon and electron microscopy

    NASA Astrophysics Data System (ADS)

    Bolze, Frédéric; Ftouni, Hussein; Nicoud, Jean-François; Leoni, Piero; Schwab, Yannick; Rehspringer, Jean-Luc; Mafouana, Rodrigues R.

    2013-03-01

    Nowadays, many crucial biological questions involve the observation of biological samples at different scales. Thus, optical microscopy can be associated to magnetic nuclear imaging allowing access to data from the cellular to the organ level, or can be associated to electron microscopy to reach the sub cellular level. We will describe here the design, synthesis and characterization of new bimodal probes, which can be used as dye in two-photon excited microscopy (TPEM) and electron dense markers in scanning and transmission electron microscopy (EM). In a first part, we will describe new molecular dyes with small organic systems grafted on metal atoms (Pt, Au). Such systems show good twophoton induced fluorescence and two-photon images of HeLa cells will be presented. In a second part, we will present hybrid organic-inorganic fluorescent systems with diketopyrrolopyrole-based dye grafted on iron oxide-silica core shell nanoparticles by peptide bond. Such systems present high two-photon absorption cross sections and good fluorescence quantum yields. These nanoparticles are rapidly internalized in HeLa cells and high quality two-photon images were performed with low laser power. Then we will present our results on correlative light-electron microscopy were twophoton and electron microscopy (both scanning and transmission) images were obtained on the same biological sample.

  6. Methods Development | High Resolution Electron Microscopy

    Cancer.gov

    The development of new technology and new methods has been central to our lab’s mission. One key development has been that of a complete framework for alignment, classification, and averaging of volumes derived by electron tomography that is computationally efficient and effectively accounts for the missing wedge that is inherent to limited angle electron tomography.

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

    PubMed

    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. PMID:25464144

  8. Quantitative imaging of intact cardiac tissue using remote focusing microscopy

    NASA Astrophysics Data System (ADS)

    Corbett, A. D.; Burton, R. A. B.; Bub, G.; Wilson, T.

    2015-03-01

    Remote focussing microscopy offers many advantages when acquiring volumetric data from living tissue. The all-optical means of refocussing does not agitate the specimen by moving either the stage or imaging objective. Aberrationcompensated imaging extends over volumes as large as 450 ?m x 450 ?m x 200 ?m (X, Y and Z) allowing data to be collected from hundreds of cells. The speed with which refocussing can be achieved is limited only by the mechanical movement of a small (2 mm diameter) mirror. Using a pair of oblique imaging planes to rapidly acquire (<200ms) depth information temporally freezes residual tissue motion in the arrested heart. This paper discusses the progress of remote focussing microscopy from a novel imaging technique to a reliable tool in the life sciences. Specifically, we describe recent efforts to achieve the accurate calibration of both distance and orientation within the imaging volume. Using a laser machined fluorescent specimen it is possible to identify, with high sensitivity, small (<1%) depth-dependent magnification changes which are a linear function of axial misalignment of the imaging objective. The sensitivity of the calibration procedure limits distortion to <1 ?m over the entire imaging volume. This work finds direct application in identifying the microscopic effects of chronic disease in the living heart.

  9. Segmentation and learning in the quantitative analysis of microscopy images

    NASA Astrophysics Data System (ADS)

    Ruggiero, Christy; Ross, Amy; Porter, Reid

    2015-02-01

    In material science and bio-medical domains the quantity and quality of microscopy images is rapidly increasing and there is a great need to automatically detect, delineate and quantify particles, grains, cells, neurons and other functional "objects" within these images. These are challenging problems for image processing because of the variability in object appearance that inevitably arises in real world image acquisition and analysis. One of the most promising (and practical) ways to address these challenges is interactive image segmentation. These algorithms are designed to incorporate input from a human operator to tailor the segmentation method to the image at hand. Interactive image segmentation is now a key tool in a wide range of applications in microscopy and elsewhere. Historically, interactive image segmentation algorithms have tailored segmentation on an image-by-image basis, and information derived from operator input is not transferred between images. But recently there has been increasing interest to use machine learning in segmentation to provide interactive tools that accumulate and learn from the operator input over longer periods of time. These new learning algorithms reduce the need for operator input over time, and can potentially provide a more dynamic balance between customization and automation for different applications. This paper reviews the state of the art in this area, provides a unified view of these algorithms, and compares the segmentation performance of various design choices.

  10. Immuno correlative light and electron microscopy on Tokuyasu cryosections.

    PubMed

    Oorschot, Viola M J; Sztal, Tamar E; Bryson-Richardson, Robert J; Ramm, Georg

    2014-01-01

    Finding a rare structure by electron microscopy is the equivalent of finding a "needle in a haystack." Correlative light- and immunoelectron microscopy (CLEM) on Tokuyasu cryosections is a sophisticated technique to address this challenge. Hereby, fluorescently labeled structures of interest are identified in an overview image by light microscopy and subsequently traced in electron microscopy. While the direct transfer and imaging of the same sections from optical to electron microscopy enables straightforward correlation, the sample preparation is crucial and technically demanding. We provide a detailed guide outlining the critical steps for sample embedding, cryosectioning, immunolabeling, and imaging. In the example provided, we use CLEM to trace aggregates formed in a zebrafish myopathy model expressing enhanced green fluorescent protein (eGFP) tagged actin. In our case, only a few muscle fibers express eGFP-actin with a subset of fibers containing aggregates. By fluorescence microscopy, we are able to identify the aggregates in the zebrafish tissue, and we subsequently, use immunoelectron microscopy to image the same structures at high resolution. The CLEM method described here using Tokuyasu cryosections can be applied to a large range of samples including small organisms, tissue samples, and cells. PMID:25287844

  11. 1 In-situ Transmission Electron 2 Microscopy Observations of

    E-print Network

    Ferreira, Paulo J.

    of the nanoparticles by considering the localized heating from the electron beam. For isolated nano- particles, beam1 In-situ Transmission Electron 2 Microscopy Observations of 3 Sublimation in Silver Nanoparticles different from that of bulk materials and 15 may cause problems in applications where 16 the particles

  12. RESEARCH NEWS VOLUME 12 ELECTRON MICROSCOPY SPECIAL ISSUE 7

    E-print Network

    Espinosa, Horacio D.

    Microscopically wearing issues MICROSCOPY A biocompatible and biodegradable organic electronic device could change be made into flexible electronics. However, if they also have the added advantage of being biodegradable they could potentially be used in resorbable medical implants or for drug delivery. In their quest

  13. Reflection Electron Microscopy and Spectroscopy for Surface Analysis

    E-print Network

    Wang, Zhong L.

    -losses. Accurate structure analysis is possible using the purely elastically scattered electrons, the scattering the surface structure. There are several techniques, such as weak-beam dark-field and surface profile imaging1 Reflection Electron Microscopy and Spectroscopy for Surface Analysis by Zhong Lin Wang

  14. Scanning electron microscopy of prenatal muscle development in the mouse

    Microsoft Academic Search

    N. C. Stickland

    1982-01-01

    Scanning electron microscopy was used to study prenatal muscle development in mouse fetuses ranging from 12 days to 18 days gestation. Some transmission electron micrographs were also used for comparison. At 12 days no myofibres were evident although at 13 days long fibres surrounded by many mononucleated cells could be seen. At 14 days bundles of primary myofibres were observed

  15. Drift correction for scanning-electron microscopy

    E-print Network

    Snella, Michael T

    2010-01-01

    Scanning electron micrographs at high magnification (100,000x and up) are distorted by motion of the sample during image acquisition, a phenomenon called drift. We propose a method for correcting drift distortion in images ...

  16. Structure of Wet Specimens in Electron Microscopy

    ERIC Educational Resources Information Center

    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)

  17. 3D Correlative Imaging | High Resolution Electron Microscopy

    Cancer.gov

    One key area of interest for the lab has been to close the 3D imaging gap, finding ways to image whole cells and tissues at high resolution. Focused ion beam scanning electron microscopy (FIB-SEM, or otherwise known as ion abrasion scanning electron microscopy, IA-SEM) uses a scanning electron beam to image the face of a fixed, resin-embedded sample, and an ion beam to remove “slices” of the sample, resulting in a sequential stack of high resolution images.

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

    PubMed

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

    2014-05-01

    Correlative microscopy incorporates the specificity of fluorescent protein labeling into high-resolution electron micrographs. Several approaches exist for correlative microscopy, most of which have used the green fluorescent protein (GFP) as the label for light microscopy. Here we use chemical tagging and synthetic fluorophores instead, in order to achieve protein-specific labeling, and to perform multicolor imaging. We show that synthetic fluorophores preserve their post-embedding fluorescence in the presence of uranyl acetate. Post-embedding fluorescence is of such quality that the specimen can be prepared with identical protocols for scanning electron microscopy (SEM) and transmission electron microscopy (TEM); this is particularly valuable when singular or otherwise difficult samples are examined. We show that synthetic fluorophores give bright, well-resolved signals in super-resolution light microscopy, enabling us to superimpose light microscopic images with a precision of up to 25 nm in the x-y plane on electron micrographs. To exemplify the preservation quality of our new method we visualize the molecular arrangement of cadherins in adherens junctions of mouse epithelial cells. PMID:24698954

  19. Correlative light and electron microscopy in parasite research.

    PubMed

    Loussert, Céline; Forestier, Claire-Lise; Humbel, Bruno M

    2012-01-01

    The interaction of a parasite and a host cell is a complex process, which involves several steps: (1) attachment to the plasma membrane, (2) entry inside the host cell, and (3) hijacking of the metabolism of the host. In biochemical experiments, only an event averaged over the whole cell population can be analyzed. The power of microscopy, however, is to investigate individual events in individual cells. Therefore, parasitologists frequently perform experiments with fluorescence microscopy using different dyes to label structures of the parasite or the host cell. Though the resolution of light microscopy has greatly improved, it is not sufficient to reveal interactions at the ultrastructural level. Furthermore, only specifically labeled structures can be seen and related to each other. Here, we want to demonstrate the additional value of electron microscopy in this area of research. Investigation of the different steps of parasite-host cell interaction by electron microscopy, however, is often hampered by the fact that there are only a few cells infected, and therefore it is difficult to find enough cells to study. A solution is to profit from low magnification, hence large overview, and specific location of the players by fluorescence labels in a light microscope with the high power resolution and structural information provided by an electron microscope, in short by correlative light and electron microscopy. PMID:22857923

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

    PubMed

    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. PMID:25638065

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

    NASA Astrophysics Data System (ADS)

    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.

  2. Quantitative flaw characterization with scanning laser acoustic microscopy

    NASA Technical Reports Server (NTRS)

    Generazio, E. R.; Roth, D. J.

    1986-01-01

    Surface roughness and diffraction are two factors that have been observed to affect the accuracy of flaw characterization with scanning laser acoustic microscopy. Inaccuracies can arise when the surface of the test sample is acoustically rough. It is shown that, in this case, Snell's law is no longer valid for determining the direction of sound propagation within the sample. The relationship between the direction of sound propagation within the sample, the apparent flaw depth, and the sample's surface roughness is investigated. Diffraction effects can mask the acoustic images of minute flaws and make it difficult to establish their size, depth, and other characteristics. It is shown that for Fraunhofer diffraction conditions the acoustic image of a subsurface defect corresponds to a two-dimensional Fourier transform. Transforms based on simulated flaws are used to infer the size and shape of the actual flaw.

  3. Quantitative Localization Microscopy: Effects of Photophysics and Labeling Stoichiometry

    PubMed Central

    Szymborska, Anna; Lidke, Keith A.; Rieger, Bernd; Stallinga, Sjoerd

    2015-01-01

    Quantification in localization microscopy with reversibly switchable fluorophores is severely hampered by the unknown number of switching cycles a fluorophore undergoes and the unknown stoichiometry of fluorophores on a marker such as an antibody. We overcome this problem by measuring the average number of localizations per fluorophore, or generally per fluorescently labeled site from the build-up of spatial image correlation during acquisition. To this end we employ a model for the interplay between the statistics of activation, bleaching, and labeling stoichiometry. We validated our method using single fluorophore labeled DNA oligomers and multiple-labeled neutravidin tetramers where we find a counting error of less than 17% without any calibration of transition rates. Furthermore, we demonstrated our quantification method on nanobody- and antibody-labeled biological specimens. PMID:25992915

  4. Estimating the age of Antarctic larval fish from otolith microstructure using light and electron microscopy

    Microsoft Academic Search

    James J. Ruzicka; R. L. Radtke

    1995-01-01

    Larval fish of Antarctica have very narrow rings on their otoliths (Gobionotothen gibberifrons and Lepidonotothen larseni), determined using light and scanning electron microscopy, are compared. Rings 0.4 µm wide were observed on otoliths viewed under electron microscopy; however, light microscopy could only resolve rings ? 0.5 µm wide. Scanning electron microscopy is more time consuming and costly than light microscopy

  5. The identification of burnt matches by scanning electron microscopy\\/energy dispersive X-ray spectrometry

    Microsoft Academic Search

    Yueh-Hsiang Chen

    This study is first placed on the characterization of various burnt matches by scanning electron microscopy\\/energy dispersive X-ray spectrometry (SEM\\/EDS). The morphological and elemental features were used to investigate fire residues and to increase the discriminating effect of burnt matches. To find if there was further discrimination method, the cluster analysis of 74 boxes of matches based on the semi-quantitative

  6. Investigation of Chocolate Surfaces Using Profilometry and Low Vacuum Scanning Electron Microscopy

    Microsoft Academic Search

    Hanna Dahlenborg; Anna Millqvist-Fureby; Björn Bergenståhl; Daniel J. E. Kalnin

    2011-01-01

    In this study we establish the use of optical non-contact profilometry combined with low vacuum scanning electron microscopy\\u000a (LV SEM) for the investigation of lipid surfaces. We illustrate, by using profilometry, a methodology for investigation of\\u000a chocolate surface topology as a function of time, in the same area of interest. Both qualitative and quantitative data analysis\\u000a has been performed for

  7. Annular Dark Field Scanning Transmission Electron Microscopy of Crystals.

    NASA Astrophysics Data System (ADS)

    Loane, Russell Farley

    New contributions to the annular dark field (ADF) scanning transmission electron microscopy (STEM) imaging theory are developed and discussed. Recently, ADF STEM imaging has produced experimental images with atomic resolution and atomic number contrast (Z-contrast), but the imaging theory is still not well understood. Due to the complicated non-linear nature of the ADF STEM imaging process, simple analysis is inadequate. Therefore, the primary tool in this research is large scale numerical simulation. This thesis describes the development, verification, and exploitation of the ADF STEM simulation. First, a simple imaging theory, valid only in the thin specimen limit, is presented to provide the basis necessary to discuss and analyze the ADF STEM simulation. This theory also introduces the fundamental concepts of Z-contrast, incoherent imaging, point scatterers, and visibility. Then the ADF STEM multislice simulation and the improved frozen phonon (FPh) simulation are derived, implemented, and executed to investigate the details of the imaging process. Implications of electron channeling, dynamical diffraction, and thermal vibrations are discussed. Experimental verification of the FPh simulation accuracy is demonstrated for both coherent diffraction scattering and incoherent thermal diffuse scattering. The FPh simulation is then used to demonstrate that ADF STEM imaging of zone axis crystals follows the simple incoherent imaging model. The incoherent imaging model allows the separation of the effects of the imaging conditions from the specimen structure information in the ADF STEM image. This result is an important advance toward quantitative atomic structure imaging and is verified experimentally. The strong linkage between simple theory, simulation, and experiment is compelling evidence that this simulation technique is correct, and therefore justifies its use to make further predictions without experimental verification. The FPh calculation is used to provide guidelines for experimental image interpretation, including the image dependence on specimen thickness, detector geometry, and thermal vibration amplitude. The fundamental limitations of ADF STEM imaging, in terms of the minimum difference in specimen composition visible at a given resolution, are also explored.

  8. Atmospheric pressure scanning transmission electron microscopy

    SciTech Connect

    De Jonge, Niels [ORNL; Veith, Gabriel M [ORNL; Bigelow, Wilbur C [ORNL

    2010-01-01

    Scanning transmission electron microscope (STEM) images of gold nanoparticles (2.1 nm average diameter) at atmospheric pressure have been recorded through a 0.36 mm thick mixture of CO, O2 and He. This was accomplished using a reaction cell consisting of two electron-transparent silicon nitride membranes mounted on a specially designed specimen rod. Gas flow occurred through plastic tubing from the outside of the microscope to the specimen region and back. Gold nanoparticles of a full width half maximum diameter of 1.0 nm were visible above the background noise and the achieved resolution was 0.5 nm in accordance with calculations of the beam broadening.

  9. Axial ion–electron emission microscopy of IC radiation hardness

    Microsoft Academic Search

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

    2002-01-01

    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

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

    Microsoft Academic Search

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

    2002-01-01

    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

  11. Correlative video-light-electron microscopy: development, impact and perspectives.

    PubMed

    Rizzo, Riccardo; Parashuraman, Seetharaman; Luini, Alberto

    2014-08-01

    Green fluorescent protein (GFP)-based video microscopy can provide profound insight into biological processes by generating information on the 'history,' or dynamics, of the cellular structures involved in such processes in live cells. A crucial limitation of this approach, however, is that many such structures may not be resolved by light microscopy. Like more recent super-resolution techniques, correlative video-light-electron microscopy (CLEM) was developed to overcome this limitation. CLEM integrates GFP-based video microscopy and electron microscopy through a series of ancillary techniques, such as proper fixation, hybrid labeling and retracing, and so provides sufficient resolution as well as, crucially, cellular 'context' to the fluorescent dynamic structures of interest. CLEM 'multiplies' the power of video microscopy and is having an important impact in several areas cell and developmental biology. Here, we discuss potential, limitations and perspectives of correlative approaches aimed at integrating the unique insight generated by video microscopy with information from other forms of imaging. PMID:25030356

  12. Journal of Electron Microscopy 53(3): 257266 (2004) Japanese Society of Microscopy Full-length paper

    E-print Network

    Pennycook, Steve

    2004-01-01

    Journal of Electron Microscopy 53(3): 257­266 (2004)© Japanese Society of Microscopy ............................................................................................................................................................................................................................................................................... Full-length paper HAADF-STEM imaging with sub-angstrom probes: a full Bloch wave analysis Yiping Peng1-field image formation for sub-angstrom probes in scan- ning transmission electron microscopy (STEM

  13. Transmission electron microscopy: A critical analytical tool for ULSI technology

    SciTech Connect

    Venables, David [Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States); Susnitzky, David W.; Mardinly, A. John [Materials Technology Department, Intel Corporation, 2200 Mission College Blvd., Santa Clara, California 95052 (United States)

    1998-11-24

    An overview of the capabilities and limitations of transmission electron microscopy (TEM) based analysis techniques in the context of the electronics industry is presented. The electron-beam/specimen interactions that enable morphological, crystallographic and compositional characterization with modern TEMs are briefly reviewed. Diffraction contrast, lattice and energy filtered imaging; energy dispersive x-ray spectrometry (EDS), and electron energy loss spectrometry (EELS) are reviewed and discussed. These techniques are illustrated through specific applications and case studies in the electronics industry. Particular emphasis is placed on sample preparation concerns, which represent a practical limitation to an expanded role for TEM as a critical analytical tool for ULSI technology.

  14. The CryoCapsule: Simplifying correlative light to electron microscopy

    PubMed Central

    Heiligenstein, Xavier; Heiligenstein, Jérôme; Delevoye, Cédric; Hurbain, Ilse; Bardin, Sabine; Paul-Gilloteaux, Perrine; Sengmanivong, Lucie; Régnier, Gilles; Salamero, Jean; Antony, Claude; Raposo, Graca

    2014-01-01

    Correlating complementary multiple scale images of the same object is a straightforward means to decipher biological processes. Light and electron microscopy are the most commonly used imaging techniques, yet despite their complementarity, the experimental procedures available to correlate them are technically complex. We designed and manufactured a new device adapted to many biological specimens, the CryoCapsule, that simplifies the multiple sample preparation steps, which at present separate live cell fluorescence imaging from contextual high-resolution electron microscopy, thus opening new strategies for full correlative light to electron microscopy. We tested the biological application of this highly optimized tool on three different specimens: the in-vitro Xenopus laevis mitotic spindle, melanoma cells over-expressing YFP-langerin sequestered in organized membranous subcellular organelles and a pigmented melanocytic cell in which the endosomal system was labeled with internalized fluorescent transferrin. PMID:24533564

  15. Medipix 2 detector applied to low energy electron microscopy.

    PubMed

    van Gastel, R; Sikharulidze, I; Schramm, S; Abrahams, J P; Poelsema, B; Tromp, R M; van der Molen, S J

    2009-12-01

    Low energy electron microscopy (LEEM) and photo-emission electron microscopy (PEEM) traditionally use microchannel plates (MCPs), a phosphor screen and a CCD-camera to record images and diffraction patterns. In recent years, however, MCPs have become a limiting factor for these types of microscopy. Here, we report on a successful test series using a solid state hybrid pixel detector, Medipix 2, in LEEM and PEEM. Medipix 2 is a background-free detector with an infinite dynamic range, making it very promising for both real-space imaging and spectroscopy. We demonstrate a significant enhancement of both image contrast and resolution, as compared to MCPs. Since aging of the Medipix 2 detector is negligible for the electron energies used in LEEM/PEEM, we expect Medipix to become the detector of choice for a new generation of systems. PMID:19822398

  16. Atomic resolution imaging of graphene by transmission electron microscopy.

    PubMed

    Robertson, Alex W; Warner, Jamie H

    2013-05-21

    The atomic structure of a material influences its electronic, chemical, magnetic and mechanical properties. Characterising carbon nanomaterials, such as fullerenes, nanotubes and graphene, at the atomic level is challenging due to their chemical reactivity and low atomic mass. Transmission electron microscopy and scanning probe microscopy are two of the leading methods for imaging graphene at the atomic level. Here, we report on recent advances in atomic resolution imaging of graphene using aberration-corrected high resolution transmission electron microscopy and how it has revealed many of the structural deviations from the pristine monolayer form. Structures in graphene such as vacancy defects, edges, grain boundaries, linear chains, impurity dopants, layer number, layer stacking and bond rotations are explored. PMID:23595204

  17. Atomic resolution imaging of graphene by transmission electron microscopy

    NASA Astrophysics Data System (ADS)

    Robertson, Alex W.; Warner, Jamie H.

    2013-05-01

    The atomic structure of a material influences its electronic, chemical, magnetic and mechanical properties. Characterising carbon nanomaterials, such as fullerenes, nanotubes and graphene, at the atomic level is challenging due to their chemical reactivity and low atomic mass. Transmission electron microscopy and scanning probe microscopy are two of the leading methods for imaging graphene at the atomic level. Here, we report on recent advances in atomic resolution imaging of graphene using aberration-corrected high resolution transmission electron microscopy and how it has revealed many of the structural deviations from the pristine monolayer form. Structures in graphene such as vacancy defects, edges, grain boundaries, linear chains, impurity dopants, layer number, layer stacking and bond rotations are explored.

  18. Quantitative orientation-independent differential interference contrast (DIC) microscopy

    NASA Astrophysics Data System (ADS)

    Shribak, Michael; LaFountain, James; Biggs, David; Inoué, Shinya

    2007-02-01

    We describe a new DIC technique, which records phase gradients within microscopic specimens independently of their orientation. The proposed system allows the generation of images representing the distribution of dry mass (optical path difference) in the specimen. Unlike in other forms of interference microscopes, this approach does not require a narrow illuminating cone. The orientation-independent differential interference contrast (OI-DIC) system can also be combined with orientation-independent polarization (OI-Pol) measurements to yield two complementary images: one showing dry mass distribution (which is proportional to refractive index) and the other showing distribution of birefringence (due to structural or internal anisotropy). With a model specimen used for this work -- living spermatocytes from the crane fly, Nephrotoma suturalis --- the OI-DIC image clearly reveals the detailed shape of the chromosomes while the polarization image quantitatively depicts the distribution of the birefringent microtubules in the spindle, both without any need for staining or other modifications of the cell. We present examples of a pseudo-color combined image incorporating both orientation-independent DIC and polarization images of a spermatocyte at diakinesis and metaphase of meiosis I. Those images provide clear evidence that the proposed technique can reveal fine architecture and molecular organization in live cells without perturbation associated with staining or fluorescent labeling. The phase image was obtained using optics having a numerical aperture 1.4, thus achieving a level of resolution never before achieved with any interference microscope.

  19. Identification of cartilage injury using quantitative multiphoton microscopy

    PubMed Central

    Novakofski, Kira D.; Williams, Rebecca M.; Fortier, Lisa A.; Mohammed, Hussni O.; Zipfel, Warren R.; Bonassar, Lawrence J.

    2014-01-01

    Objective Cartilage injury can lead to post-traumatic osteoarthritis (PTOA). Immediate post-trauma cellular and structural changes are not widely understood. Furthermore, current cellular-resolution cartilage imaging techniques require sectioning of cartilage and/or use of dyes not suitable for patient imaging. In this study, we used multiphoton microscopy (MPM) data with FDA-approved sodium fluorescein to identify and evaluate the pattern of chondrocyte death after traumatic injury. Method Mature equine distal metacarpal or metatarsal osteochondral blocks were injured by 30 MPa compressive loading delivered over 1 sec. Injured and control sites were imaged unfixed and in situ 1 hour post-injury with sodium fluorescein using rasterized z-scanning. MPM data was quantified in MATLAB, reconstructed in 3-D, and projected in 2-D to determine the damage pattern. Results MPM images (600 per sample) were reconstructed and analyzed for cell death. The overall distribution of cell death appeared to cluster into circular (n=7) or elliptical (n=4) patterns (p=0.006). Dead cells were also prevalent near cracks in the matrix, with only 26.3% (SE=5.0%, p<0.0001) of chondrocytes near cracks being viable. Conclusion This study demonstrates the first application of MPM for evaluating cellular-scale cartilage injury in situ in live tissue, with clinical potential for detecting early cartilage damage. With this technique, we were able to uniquely observe two death patterns resulting from the same compressive loading, which may be related to local variability in matrix structure. These results also demonstrate proof-of-concept MPM diagnostic use in detecting subtle and early cartilage damage not detectable in any other way. PMID:24185113

  20. Laboratory design for high-performance electron microscopy

    SciTech Connect

    O'Keefe, Michael A.; Turner, John H.; Hetherington, Crispin J.D.; Cullis, A.G.; Carragher, Bridget; Jenkins, Ron; Milgrim, Julie; Milligan,Ronald A.; Potter, Clinton S.; Allard, Lawrence F.; Blom, Douglas A.; Degenhardt, Lynn; Sides, William H.

    2004-04-23

    Proliferation of electron microscopes with field emission guns, imaging filters and hardware spherical aberration correctors (giving higher spatial and energy resolution) has resulted in the need to construct special laboratories. As resolutions improve, transmission electron microscopes (TEMs) and scanning transmission electron microscopes (STEMs) become more sensitive to ambient conditions. State-of-the-art electron microscopes require state-of-the-art environments, and this means careful design and implementation of microscope sites, from the microscope room to the building that surrounds it. Laboratories have been constructed to house high-sensitive instruments with resolutions ranging down to sub-Angstrom levels; we present the various design philosophies used for some of these laboratories and our experiences with them. Four facilities are described: the National Center for Electron Microscopy OAM Laboratory at LBNL; the FEGTEM Facility at the University of Sheffield; the Center for Integrative Molecular Biosciences at TSRI; and the Advanced Microscopy Laboratory at ORNL.

  1. Evaluations of carbon nanotube field emitters for electron microscopy

    NASA Astrophysics Data System (ADS)

    Nakahara, Hitoshi; Kusano, Yoshikazu; Kono, Takumi; Saito, Yahachi

    2009-11-01

    Brightness of carbon nanotube (CNT) emitters was already reported elsewhere. However, brightness of electron emitter is affected by a virtual source size of the emitter, which strongly depends on electron optical configuration around the emitter. In this work, I- V characteristics and brightness of a CNT emitter are measured under a practical field emission electron gun (e-gun) configuration to investigate availability of CNT for electron microscopy. As a result, it is obtained that an emission area of MWNT is smaller than its tip surface area, and the emission area corresponds to a five-membered-ring with 2nd nearest six-membered-rings on the MWNT cap surface. Reduced brightness of MWNT is measured as at least 2.6×109 A/m 2 sr V. It is concluded that even a thick MWNT has enough brightness under a practical e-gun electrode configuration and suitable for electron microscopy.

  2. The application of scanning electron microscopy to fractography

    SciTech Connect

    Brooks, C.R.; McGill, B.L. (Univ. of Tennessee, Knoxville, TN (United States))

    1994-10-01

    Many failures involve fracture, and determination of the fracture process is a key factor in understanding the failure. This is frequently accomplished by characterizing the topography of the fracture surface. Scanning electron microscopy has a prominent role in fractography due to three features of the scanning electron microscope (SEM): high resolution, great depth of field, and the ability to obtain chemical information via analysis of the X-rays generated by the electrons. A qualitative treatment is presented of the interaction of electrons with a sample and the effect of the SEM operating parameters on image formation, quality, and X-ray analysis. Fractographs are presented to illustrate these features of scanning electron microscopy and to illustrate the limitations and precautions in obtaining fractographs and x-ray analyses. The review is concluded with examples of fracture surface features of metallic, ceramic, and polymeric materials.

  3. Dendritic Cell with HIV | High Resolution Electron Microscopy

    Cancer.gov

    In order to study the 3D structure of the site of HIV transfer from dendritic cells to T cells (the virological synapse), the Subramaniam group used a combination of scanning electron microscopy paired with an ion beam (FIB-SEM), for 3D imaging, and transmission electron microscopy (TEM), for visualizing virions. By reconstructing 3D FIB-SEM images of dendritic cells interacting with T cells, and pairing that with higher resolution TEM images of the virological synapse, the group pieced together the following story.

  4. The Rapidly Changing Face of Electron Microscopy

    E-print Network

    Thomas, John Meurig; Leary, Rowan K.; Eggeman, Alexander S.; Midgley, Paul A.

    2015-05-07

    for the retrieval of energy-dispersive ) and electron energy-loss (EEL) spectra, can routinely ectrum images’ in which behind every image pixel lies (EDX or EEL) spectrum. By recording a tilt series of um images, 4D ‘spectrum tomograms’ produce spectral ical... . / Chemical Physics Letters 631–632 (2015) 103–113 107 Figure 4. (a) ( aluminium (blue) from an Al-5 wt%Si alloy (6100 ppm Yb), obtained from STEM-EELS an tterbium-rich precipitates [39]. (b) Surface rendered 3D elemental maps of Ag-rich (left) a face...

  5. Application of channel electron multipliers in an electron detector for low-voltage scanning electron microscopy.

    PubMed

    Hejna, J

    2008-11-01

    An electron detector containing channel electron multipliers was built and tested in the range of low-voltage scanning electron microscopy as a detector of topographic contrast. The detector can detect backscattered electrons or the sum of backscattered electrons and secondary electrons, with different amount of secondary electrons. As a backscattered electron detector it collects backscattered electrons emitted in a specific range of take-off angles and in a large range of azimuth angles enabling to obtain large solid collection angle and high collection efficiency. Two arrangements with different channel electron multipliers were studied theoretically with the use of the Monte Carlo method and one of them was built and tested experimentally. To shorten breaks in operation, a vacuum box preventing channel electron multipliers from an exposure to air during specimen exchanges was built and placed in the microscope chamber. The box is opened during microscope observations and is moved to the side of the scanning electron microscope chamber and closed during air admission and evacuation cycles enabling storing channel electron multipliers under vacuum for the whole time. Experimental tests of the detector included assessment of the type of detected electrons (secondary or backscattered), checking the tilt contrast, imaging the spatial collection efficiency, measuring the noise coefficient and recording images of different specimens. PMID:19017236

  6. Nano-fEM: protein localization using photo-activated localization microscopy and electron microscopy.

    PubMed

    Watanabe, Shigeki; Richards, Jackson; Hollopeter, Gunther; Hobson, Robert J; Davis, Wayne M; Jorgensen, Erik M

    2012-01-01

    Mapping the distribution of proteins is essential for understanding the function of proteins in a cell. Fluorescence microscopy is extensively used for protein localization, but subcellular context is often absent in fluorescence images. Immuno-electron microscopy, on the other hand, can localize proteins, but the technique is limited by a lack of compatible antibodies, poor preservation of morphology and because most antigens are not exposed to the specimen surface. Correlative approaches can acquire the fluorescence image from a whole cell first, either from immuno-fluorescence or genetically tagged proteins. The sample is then fixed and embedded for electron microscopy, and the images are correlated (1-3). However, the low-resolution fluorescence image and the lack of fiducial markers preclude the precise localization of proteins. Alternatively, fluorescence imaging can be done after preserving the specimen in plastic. In this approach, the block is sectioned, and fluorescence images and electron micrographs of the same section are correlated (4-7). However, the diffraction limit of light in the correlated image obscures the locations of individual molecules, and the fluorescence often extends beyond the boundary of the cell. Nano-resolution fluorescence electron microscopy (nano-fEM) is designed to localize proteins at nano-scale by imaging the same sections using photo-activated localization microscopy (PALM) and electron microscopy. PALM overcomes the diffraction limit by imaging individual fluorescent proteins and subsequently mapping the centroid of each fluorescent spot (8-10). We outline the nano-fEM technique in five steps. First, the sample is fixed and embedded using conditions that preserve the fluorescence of tagged proteins. Second, the resin blocks are sectioned into ultrathin segments (70-80 nm) that are mounted on a cover glass. Third, fluorescence is imaged in these sections using the Zeiss PALM microscope. Fourth, electron dense structures are imaged in these same sections using a scanning electron microscope. Fifth, the fluorescence and electron micrographs are aligned using gold particles as fiducial markers. In summary, the subcellular localization of fluorescently tagged proteins can be determined at nanometer resolution in approximately one week. PMID:23242070

  7. Nano-fEM: Protein Localization Using Photo-activated Localization Microscopy and Electron Microscopy

    PubMed Central

    Watanabe, Shigeki; Richards, Jackson; Hollopeter, Gunther; Hobson, Robert J.; Davis, Wayne M.; Jorgensen, Erik M.

    2012-01-01

    Mapping the distribution of proteins is essential for understanding the function of proteins in a cell. Fluorescence microscopy is extensively used for protein localization, but subcellular context is often absent in fluorescence images. Immuno-electron microscopy, on the other hand, can localize proteins, but the technique is limited by a lack of compatible antibodies, poor preservation of morphology and because most antigens are not exposed to the specimen surface. Correlative approaches can acquire the fluorescence image from a whole cell first, either from immuno-fluorescence or genetically tagged proteins. The sample is then fixed and embedded for electron microscopy, and the images are correlated 1-3. However, the low-resolution fluorescence image and the lack of fiducial markers preclude the precise localization of proteins. Alternatively, fluorescence imaging can be done after preserving the specimen in plastic. In this approach, the block is sectioned, and fluorescence images and electron micrographs of the same section are correlated 4-7. However, the diffraction limit of light in the correlated image obscures the locations of individual molecules, and the fluorescence often extends beyond the boundary of the cell. Nano-resolution fluorescence electron microscopy (nano-fEM) is designed to localize proteins at nano-scale by imaging the same sections using photo-activated localization microscopy (PALM) and electron microscopy. PALM overcomes the diffraction limit by imaging individual fluorescent proteins and subsequently mapping the centroid of each fluorescent spot 8-10. We outline the nano-fEM technique in five steps. First, the sample is fixed and embedded using conditions that preserve the fluorescence of tagged proteins. Second, the resin blocks are sectioned into ultrathin segments (70-80 nm) that are mounted on a cover glass. Third, fluorescence is imaged in these sections using the Zeiss PALM microscope. Fourth, electron dense structures are imaged in these same sections using a scanning electron microscope. Fifth, the fluorescence and electron micrographs are aligned using gold particles as fiducial markers. In summary, the subcellular localization of fluorescently tagged proteins can be determined at nanometer resolution in approximately one week. PMID:23242070

  8. A novel approach for correlative light electron microscopy analysis.

    PubMed

    Vicidomini, Giuseppe; Gagliani, Maria C; Cortese, Katia; Krieger, Jens; Buescher, Peter; Bianchini, Paolo; Boccacci, Patrizia; Tacchetti, Carlo; Diaspro, Alberto

    2010-03-01

    Correlative light and electron microscopy (CLEM) is a multimodal technique of increasing utilization in functional, biochemical, and molecular biology. CLEM attempts to combine multidimensional information from the complementary fluorescence light microscopy (FLM) and electron microscopy (EM) techniques to bridge the various resolution gaps. Within this approach the very same cell/structure/event observed at level can be analyzed as well by FLM and EM. Unfortunately, these studies turned out to be extremely time consuming and are not suitable for statistical relevant data. Here, we describe a new CLEM method based on a robust specimen preparation protocol, optimized for cryosections (Tokuyasu method) and on an innovative image processing toolbox for a novel type of multimodal analysis. Main advantages obtained using the proposed CLEM method are: (1) hundred times more cells/structures/events that can be correlated in each single microscopy session; (2) three-dimensional correlation between FLM and EM, obtained by means of ribbons of serial cryosections and electron tomography microscopy (ETM); (3) high rate of success for each CLEM experiment, obtained implementing protection of samples from physical damage and from loss of fluorescence; (4) compatibility with the classical immunogold and immunofluorescence labeling techniques. This method has been successfully validated for the correlative analysis of Russel Bodies subcellular compartments. PMID:19725102

  9. Attosecond electron pulses for 4D diffraction and microscopy

    PubMed Central

    Baum, Peter; Zewail, Ahmed H.

    2007-01-01

    In this contribution, we consider the advancement of ultrafast electron diffraction and microscopy to cover the attosecond time domain. The concept is centered on the compression of femtosecond electron packets to trains of 15-attosecond pulses by the use of the ponderomotive force in synthesized gratings of optical fields. Such attosecond electron pulses are significantly shorter than those achievable with extreme UV light sources near 25 nm (?50 eV) and have the potential for applications in the visualization of ultrafast electron dynamics, especially of atomic structures, clusters of atoms, and some materials. PMID:18000040

  10. Analytical quantitative theory of RF-SPM for nanocarbon electronics

    NASA Astrophysics Data System (ADS)

    Rotkin, Slava V.

    2015-03-01

    Among a variety of Scanning Probe Microscopy (SPM) tools RF- or microwave-SPM has recommended itself as a versatile characterization tool, recently demonstrated capability to map electronic properties of nanocarbon materials non-destructively and with nanometer resolution. The transparent theory of RF-SPM sensing mechanism is however lacking, mostly limited to numerical or empirical solutions, especially when studying low-dimensional quantum objects, such as nanotubes/nanowires (NT/NW), where the classical description is often invalid. One-dimensional electronic structure of the NT/NW, weak screening of Coulomb interaction and finite e-e compressibility were successfully taken into account to provide an analytic form of its quasi-stationary (due to low RF frequency of the excitation) selfconsistent response. SPM tip response function was, in turn, efficiently analyzed in multipole series, and non-perturbatively diagrammatically summed in the sense of the Random Phase Approximation. Resulting theory shows transparently the physics of RF-SPM sensing mechanism, simultaneously allowing a quantitative analysis of recent RF-SPM data on nanotube electronic devices [E. Seabron, S. MacLaren, X. Xie, SV. Rotkin, JA. Rogers, WL. Wilson, unpublished]. Support by AFOSR (# FA9550-11-1-0185) is acknowledged.

  11. Helium ion microscopy and energy selective scanning electron microscopy - two advanced microscopy techniques with complementary applications

    NASA Astrophysics Data System (ADS)

    Rodenburg, C.; Jepson, M. A. E.; Boden, Stuart A.; Bagnall, Darren M.

    2014-06-01

    Both scanning electron microscopes (SEM) and helium ion microscopes (HeIM) are based on the same principle of a charged particle beam scanning across the surface and generating secondary electrons (SEs) to form images. However, there is a pronounced difference in the energy spectra of the emitted secondary electrons emitted as result of electron or helium ion impact. We have previously presented evidence that this also translates to differences in the information depth through the analysis of dopant contrast in doped silicon structures in both SEM and HeIM. Here, it is now shown how secondary electron emission spectra (SES) and their relation to depth of origin of SE can be experimentally exploited through the use of energy filtering (EF) in low voltage SEM (LV-SEM) to access bulk information from surfaces covered by damage or contamination layers. From the current understanding of the SES in HeIM it is not expected that EF will be as effective in HeIM but an alternative that can be used for some materials to access bulk information is presented.

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

    PubMed

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

    2013-02-01

    A 12-year-old boy with difficulty in wound healing and abnormal scars since early childhood was examined. Light microscopy showed loose and disperse dermal collagen with rare bundles, and fibroblasts show an irregular morphology. The fibrous sheath of hair presented a normal parallel distribution of the collagen fibers with normal spindle-shaped fibroblasts. Transmission electron microscopy also found disorganized collagen fibers, which were seen in a same field in longitudinal and cross sections. With high magnifications, an amorphous substance was seen near to loose collagen fibers, which showed variable diameters in cross sections. Scanning electron microscopy of the dermis showed disorganized collagen fibers and with higher magnification, important collagen disarrangement was observed with isolated and crossed-over fibers. PMID:23051630

  13. Renal basement membranes by ultrahigh resolution scanning electron microscopy

    Microsoft Academic Search

    Kazue Hironaka; Hirofumi Makino; Yasushi Yamasaki; Zensuke Ota

    1993-01-01

    Renal basement membranes by ultrahigh resolution scanning electron microscopy. Three-dimensional ultrastructures of basement membranes of the rat kidney were investigated with an ultrahigh resolution scanning electron microscope (HSEM) equipped with a resolving power of 0.5 nm. All cellular components were extracted from renal cortical tissues by sequential-detergent treatment. Four types of acellular basement membranes were observed after tannin-osmium conductive staining:

  14. Analytical electron microscopy of stainless steel weld metal

    Microsoft Academic Search

    Lyman

    1979-01-01

    The technique of analytical electron microscopy in a Scanning Transmission Electron Microscope (STEM) fitted with an x-ray spectrometer is described. This high spatial resolution microanalysis technique is applied to duplex Type 304L stainless steel weld metal. Small inclusions in these steels may be either iron-rich or manganese-rich silicates and may contain small amounts of elements not listed in the normal

  15. EMAN2: An extensible image processing suite for electron microscopy

    Microsoft Academic Search

    Guang Tang; Liwei Peng; Philip R. Baldwin; Deepinder S. Mann; Wen Jiang; Ian Rees; Steven J. Ludtke

    2007-01-01

    EMAN is a scientific image processing package with a particular focus on single particle reconstruction from transmission electron microscopy (TEM) images. It was first released in 1999, and new versions have been released typically 2–3 times each year since that time. EMAN2 has been under development for the last two years, with a completely refactored image processing library, and a

  16. Electron Microscopy of Molluscan Crossed-Lamellar Microstructure

    Microsoft Academic Search

    N. V. Wilmot; D. J. Barber; J. D. Taylor; A. L. Graham

    1992-01-01

    The morphology of the molluscan shell microstructure cross-lamellar structure (XLM) was studied by a scanning electron microscopy (SEM) examination of a variety of species (Patella vulgata, Littorina littorea, L. nigrolineata, L. obtusata, L. saxatilis, Oliva sayana, Conus litteratus, C. magus, Pomatias elegans, Acanthopleura brevispinosa, and Arca tetragona). Two of the gastropod species (O. sayana and L. littorea) were also examined

  17. A national facility for biological cryo-electron microscopy

    SciTech Connect

    Saibil, Helen R., E-mail: h.saibil@mail.cryst.bbk.ac.uk [Birkbeck College, Malet Street, London WC1E 7HX (United Kingdom); Grünewald, Kay [University of Oxford, Oxford OX3 7BN (United Kingdom); Stuart, David I. [University of Oxford, Oxford OX3 7BN (United Kingdom); Diamond Light Source, Didcot OX11 0DE (United Kingdom); Birkbeck College, Malet Street, London WC1E 7HX (United Kingdom)

    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.

  18. Sensitization of inconel 600. II. Analytical electron microscopy

    Microsoft Academic Search

    P. G. Caceres; B. Ralph; G. C. Allen; R. K. Wild

    1989-01-01

    Analytical electron microscopy has been used to study the effect of trace impurity elements, such as carbon, phosphorus, boron and silicon, on the microstructural characteristics of Inconel 600. Sulphide particles, rich in manganese and chromium, have been detected in association with both titanium nitride and chromium carbide, and the structure, lattice parameters and crystallographic orientation relationship between the ?-M23C6 and

  19. Seeing Inside Materials by Aberration-Corrected Electron Microscopy

    SciTech Connect

    Pennycook, Stephen J [ORNL; Borisevich, Albina Y [ORNL; van Benthem, Klaus [ORNL; Oxley, Mark P [ORNL; Luo, Weidong [ORNL; Oh, Sang Ho [ORNL; Kumar, Dhananjay [ORNL; Werner, P [Max Planck Institute of Microstructure Physics; Zakharov, N. D. [Max Planck Institute of Microstructure Physics; Molina Rubio, Sergio I [ORNL; Marinopulos, Apostolos [Vanderbilt University; Pantelides, Sokrates T [ORNL

    2008-01-01

    The motivation for aberration correction in electron microscopy was primarily to improve lateral resolution, and its successful achievement enabled the direct imaging of sub- ngstrom lattice spacings in a crystal. However, the smaller probe results in greatly enhanced sensitivity for imaging individual atoms, and in addition, the wider useable aperture results in a smaller depth of field.

  20. DISLOCATION IMAGES IN HIGH RESOLUTION SCANNING ELECTRON MICROSCOPY

    E-print Network

    Paris-Sud XI, Université de

    385 DISLOCATION IMAGES IN HIGH RESOLUTION SCANNING ELECTRON MICROSCOPY R. M. STERN Department images, although it is obvious that the resolution in the back scattered image is 3-5 times poorer than in the back scattered image, but it should be noted that the resolution in the thick sample is further reduced

  1. 'GIARDIA MURIS': SCANNING ELECTRON MICROSCOPY OF IN VITRO EXCYSTATION

    EPA Science Inventory

    A recently developed in vitro excystation procedure results in almost total excystation of Giardia muris, an intestinal parasite of mice. The present experiment examines the G. muris cyst morphology by scanning electron microscopy and evaluates the efficacy of the excystation pro...

  2. Towards neural circuit reconstruction with volume electron microscopy techniques

    E-print Network

    Born, Richard

    Towards neural circuit reconstruction with volume electron microscopy techniques Kevin L Briggman tissue, necessary to reconstruct even local neural circuits, have, however, been inhibited the computations performed by local neural circuits by recording from one neuron at a time, and instead need

  3. Studying localized corrosion using liquid cell transmission electron microscopy.

    PubMed

    Chee, See Wee; Pratt, Sarah H; Hattar, Khalid; Duquette, David; Ross, Frances M; Hull, Robert

    2015-01-01

    Localized corrosion of Cu and Al thin films exposed to aqueous NaCl solutions was studied using liquid cell transmission electron microscopy (LCTEM). We demonstrate that potentiostatic control can be used to initiate pitting and that local compositional changes, due to focused ion beam implantation of Au(+) ions, can modify the corrosion susceptibility of Al films. PMID:25388023

  4. DICHOTOMOUS SAMPLERS MODIFIED FOR USE WITH ELECTRON MICROSCOPY

    EPA Science Inventory

    Large sulfate artifacts up to 2 um in diameter were observed by scanning electron microscopy for the fine particle fraction collected in dichotomous samplers. he artifacts were attributed to small liquid particles that piled up on the filter, coalesced, and later dried as larger ...

  5. Refining Mitochondria Segmentation in Electron Microscopy Imagery with Active Surfaces

    E-print Network

    Fua, Pascal

    Refining Mitochondria Segmentation in Electron Microscopy Imagery with Active Surfaces Anne Jorstad for refining the boundary surfaces of mitochondria segmentation data. We exploit the fact that mitochondria imagery. Our resulting surfaces are seen to fit very accurately to the mitochondria membranes, more

  6. SPECIMEN PREPARATION for SCANNING ELECTRON MICROSCOPY1 Paul E. Stutzman

    E-print Network

    Bentz, Dale P.

    Portland cement clinker, cement powder, cement pastes, mortars, and hardened portland cement concrete [3 particles and hardened portland cement paste. The BE image contrast is generated by the different phases. The increased application of scanning electron microscopy in cement and concrete investigations has brought

  7. NON DESTRUCTIVE TESTING OF ELECTRONIC DEVICES BY ACOUSTIC MICROSCOPY

    E-print Network

    Paris-Sud XI, Université de

    815 NON DESTRUCTIVE TESTING OF ELECTRONIC DEVICES BY ACOUSTIC MICROSCOPY J. ATTAL and G. CAMBON destructive de surfaces et sous-surfaces de structures et de composants relevant de la physique des solides in solids are particularly suitable for non destructive observation of surface and subsurface ofsolid state

  8. High resolution scanning electron microscopy of plant chromosomes

    Microsoft Academic Search

    G. Wanner; H. Formanek; R. Martin; R. G. Herrmann

    1991-01-01

    A preparation technique for high resolution field emission scanning electron microscopy of plant chromosomes is described. The technique was optimized to use standard squash preparations of mitotic and meiotic chromosomes from root tips of barley, wheat, and rye. After light microscopic observation and documentation, the same object can be investigated with a 100-fold higher resolution using a field emission scanning

  9. On the scanning electron microscopy of thin specimens in transmission

    Microsoft Academic Search

    K. H. Herrmann

    1974-01-01

    The possibilities of scanning electron microscopy were tested in two ways. Based on previous work on a high resolution scanning transmission microscope, systems with field emission guns were tested. It was shown that treating the field emission gun with oxygen increases the brightness of the system. Using an Elmiskope 101 a resolution of about 3nm could be achieved. An energy-analyzer

  10. Scanning electron microscopy and x-ray microanalysis

    Microsoft Academic Search

    Lawes

    1987-01-01

    This introduction to the use of scanning electron microscopy (SEM) covers in detail instrumentation, sample preparation, and X-ray microanalysis and instrumentation. Emphasis is on developing an understanding of SEM and becoming proficient at its procedures. Mathematics is kept to a minimum. A chapter on instrumentation covers principles of operation, specimen\\/electrode interactions, detectors, and operating conditions and limitations. The discussion of

  11. Analytical Electron Microscopy and the Problem of Potassium Diffusion1

    Microsoft Academic Search

    Ben A. van der Pluijm; JUNG HOO LEE; DONALD R. PEACOR

    1988-01-01

    Diffusion of K during analytical electron microscopy (AEM) results in anomalously low count rates for this element. As the analysis area and specimen thickness decrease, count rates become dispro- portionally lower. Adularia and muscovite show different diffusion profiles during AEM; for muscovite a strong dependence of diffusion on crystallographic orientation has been observed. Conditions giving rise to reliable chemical data

  12. Breaking resolution limits in ultrafast electron diffraction and microscopy

    PubMed Central

    Baum, Peter; Zewail, Ahmed H.

    2006-01-01

    Ultrafast electron microscopy and diffraction are powerful techniques for the study of the time-resolved structures of molecules, materials, and biological systems. Central to these approaches is the use of ultrafast coherent electron packets. The electron pulses typically have an energy of 30 keV for diffraction and 100–200 keV for microscopy, corresponding to speeds of 33–70% of the speed of light. Although the spatial resolution can reach the atomic scale, the temporal resolution is limited by the pulse width and by the difference in group velocities of electrons and the light used to initiate the dynamical change. In this contribution, we introduce the concept of tilted optical pulses into diffraction and imaging techniques and demonstrate the methodology experimentally. These advances allow us to reach limits of time resolution down to regimes of a few femtoseconds and, possibly, attoseconds. With tilted pulses, every part of the sample is excited at precisely the same time as when the electrons arrive at the specimen. Here, this approach is demonstrated for the most unfavorable case of ultrafast crystallography. We also present a method for measuring the duration of electron packets by autocorrelating electron pulses in free space and without streaking, and we discuss the potential of tilting the electron pulses themselves for applications in domains involving nuclear and electron motions. PMID:17056711

  13. Direct Visualization of Dendrite Nucleation and Growth Kinetics during Lithium Deposition with in situ Electrochemical Transmission Electron Microscopy

    SciTech Connect

    Sacci, Robert L [ORNL; Dudney, Nancy J [ORNL; More, Karren Leslie [ORNL; Browning, Nigel [Pacific Northwest National Laboratory (PNNL); Unocic, Raymond R [ORNL

    2014-01-01

    Formation of Li dendrites is a major safety concern existing in Li-ion secondary batteries. A quantitative electrochemistry method to investigate the dendrite nucleation and growth mechanisms at high spatial is presented. Cyclic voltammetry, in combination with in situ electrochemical transmission electron microscopy (in situ ec-TEM), was used to quantitatively characterize dendrite nucleation and growth mechanisms from a Au working electrode and within a 1.2M LiPF6 EC:DMC electrolyte.

  14. Energy levels of few-electron quantum dots imaged and characterized by atomic force microscopy

    PubMed Central

    Cockins, Lynda; Miyahara, Yoichi; Bennett, Steven D.; Clerk, Aashish A.; Studenikin, Sergei; Poole, Philip; Sachrajda, Andrew; Grutter, Peter

    2010-01-01

    Strong confinement of charges in few-electron systems such as in atoms, molecules, and quantum dots leads to a spectrum of discrete energy levels often shared by several degenerate states. Because the electronic structure is key to understanding their chemical properties, methods that probe these energy levels in situ are important. We show how electrostatic force detection using atomic force microscopy reveals the electronic structure of individual and coupled self-assembled quantum dots. An electron addition spectrum results from a change in cantilever resonance frequency and dissipation when an electron tunnels on/off a dot. The spectra show clear level degeneracies in isolated quantum dots, supported by the quantitative measurement of predicted temperature-dependent shifts of Coulomb blockade peaks. Scanning the surface shows that several quantum dots may reside on what topographically appears to be just one. Relative coupling strengths can be estimated from these images of grouped coupled dots. PMID:20457938

  15. Measurement errors in entanglement-assisted electron microscopy

    E-print Network

    Hiroshi Okamoto

    2014-01-29

    The major resolution-limiting factor in cryoelectron microscopy of unstained biological specimens is radiation damage by the very electrons that are used to probe the specimen structure. To address this problem, an electron microscopy scheme that employs quantum entanglement to enable phase measurement precision beyond the standard quantum limit has recently been proposed {[}Phys. Rev. A \\textbf{85}, 043810{]}. Here we identify and examine in detail measurement errors that will arise in the scheme. An emphasis is given to considerations concerning inelastic scattering events because in general schemes assisted with quantum entanglement are known to be highly vulnerable to lossy processes. We find that the amount of error due both to elastic and inelastic scattering processes are acceptable provided that the electron beam geometry is properly designed.

  16. Organization of the Outer Plexiform Layer of the Primate Retina: Electron Microscopy of Golgi-Impregnated Cells

    Microsoft Academic Search

    Helga Kolb

    1970-01-01

    Golgi-impregnated retinae of rhesus monkeys have been examined by serial section electron microscopy to establish in a quantitative manner the neural connexions in the outer plexiform layer. The results have shown that there are two types of midget bipolar cell, here called the invaginating midget bipolar and the flat midget bipolar. Both types of midget bipolar are exclusive to a

  17. Classification of single particles by neural networks based on the computer-controlled scanning electron microscopy data

    Microsoft Academic Search

    Philip K. Hopke; Xin-Hua Song

    1997-01-01

    The identification of sources of particles found in chemical process equipment such as photographic printer cabinets and their quantitative apportionment to those sources could lead to effective control strategies that would improve productivity and customer satisfaction with the service. Computer-controlled scanning electron microscopy (CCSEM) has proven to be a powerful tool in the characterization of individual particles. Thus, in this

  18. Concatenated Metallothionein as a Clonable Gold Label for Electron Microscopy

    PubMed Central

    Mercogliano, Christopher P.; DeRosier, David J.

    2007-01-01

    Localization of proteins in cells or complexes using electron microscopy has mainly relied upon the use of heavy metal clusters, which can be difficult to direct to sites of interest. For this reason, we would like to develop a clonable tag analogous to the clonable fluorescent tags common to light microscopy. Instead of fluorescing, such a tag would initiate formation of a heavy metal cluster. To test the feasibility of such a tag, we exploited the metal-binding protein, metallothionein (MT). We created a chimeric protein by fusing one or two copies of the MT gene to the gene for maltose binding protein. These chimeric proteins bound many gold atoms, with a conservative value of 16 gold atoms per copy of metallothionein. Visualization of gold-labeled fusion proteins by scanning electron microscopy required one copy of metallothionein while transmission electron microscopy required two copies. Images of frozen-hydrated samples of simple complexes made with anti-MBP antibodies hint at the usefulness of this method. PMID:17692533

  19. Robert Feulgen Prize Lecture 1995. Electronic light microscopy: present capabilities and future prospects.

    PubMed

    Shotton, D M

    1995-08-01

    Electronic light microscopy involves the combination of microscopic techniques with electronic imaging and digital image processing, resulting in dramatic improvements in image quality and ease of quantitative analysis. In this review, after a brief definition of digital images and a discussion of the sampling requirements for the accurate digital recording of optical images, I discuss the three most important imaging modalities in electronic light microscopy--video-enhanced contrast microscopy, digital fluorescence microscopy and confocal scanning microscopy--considering their capabilities, their applications, and recent developments that will increase their potential. Video-enhanced contrast microscopy permits the clear visualisation and real-time dynamic recording of minute objects such as microtubules, vesicles and colloidal gold particles, an order of magnitude smaller than the resolution limit of the light microscope. It has revolutionised the study of cellular motility, and permits the quantitative tracking of organelles and gold-labelled membrane bound proteins. In combination with the technique of optical trapping (optical tweezers), it permits exquisitely sensitive force and distance measurements to be made on motor proteins. Digital fluorescence microscopy enables low-light-level imaging of fluorescently labelled specimens. Recent progress has involved improvements in cameras, fluorescent probes and fluorescent filter sets, particularly multiple bandpass dichroic mirrors, and developments in multiparameter imaging, which is becoming particularly important for in situ hybridisation studies and automated image cytometry, fluorescence ratio imaging, and time-resolved fluorescence. As software improves and small computers become more powerful, computational techniques for out-of-focus blur deconvolution and image restoration are becoming increasingly important. Confocal microscopy permits convenient, high-resolution, non-invasive, blur-free optical sectioning and 3D image acquisition, but suffers from a number of limitations. I discuss advances in confocal techniques that address the problems of temporal resolution, spherical and chromatic aberration, wavelength flexibility and cross-talk between fluorescent channels, and describe new optics to enhance axial resolution and the use of two-photon excitation to reduce photobleaching. Finally, I consider the desirability of establishing a digital image database, the BioImage database, which would permit the archival storage of, and public Internet access to, multidimensional image data from all forms of biological microscopy. Submission of images to the BioImage database would be made in coordination with the scientific publication of research results based upon these data.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:8536077

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

    PubMed Central

    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. PMID:19915208

  1. Generation and Application of Bessel Beams in Electron Microscopy

    E-print Network

    Vincenzo Grillo; Jérémie Harris; Gian Carlo Gazzadi; Roberto Balboni; Erfan Mafakheri; Mark R. Dennis; Stefano Frabboni; Robert W. Boyd; Ebrahim Karimi

    2015-05-28

    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 electro-optical configuration used experimentally. We show that by optimizing our nanofabrication recipe, electron Bessel beams can be generated with efficiencies reaching $37 \\pm 3\\%$. 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. Finally, we discuss a specific potential application of electron Bessel beams in scanning transmission electron microscopy.

  2. Photooxidation technology for correlated light and electron microscopy.

    PubMed

    Meisslitzer-Ruppitsch, C; Röhrl, C; Neumüller, J; Pavelka, M; Ellinger, A

    2009-09-01

    The combination of the capabilities of light microscopical techniques with the power of resolution of electron microscopy along with technical advances has led to a gradual decline of the gap between classical light and electron microscopy. Among the correlative techniques using the synergistic opportunities, photooxidation methods have been established as valuable tools for visualizing cell structures at both light and electron microscopic level. Fluorescent dyes are used to oxidize the substrate diaminobenzidine, which in its oxidized state forms fine granular precipitates. Stained with osmium, the diaminobenzidine precipitates are well discernible in the electron microscope, thus labelling and defining the cellular structures, which at light microscopy level are recorded by fluorescent probes. The underlying photooxidation reaction is based on the excitation of free oxygen radicals that form upon illumination of fluorochromes; this is a central step in the procedure, which mainly influences the success of the method. This article summarizes basic steps of the technology and progresses, shows efforts and elaborated pathways, and focuses on methodical solutions as to the applicability of different fluorochromes, as well as conditions for fine structural localizations of the reaction products. PMID:19754726

  3. Atomic force microscopy (AFM), transmission electron microscopy (TEM) and scanning electron microscopy (SEM) of nanoscale plate-shaped second phase particles

    Microsoft Academic Search

    I. Sobchenko; J. Pesicka; D. Baither; W. Stracke; T. Pretorius; L. Chi; R. Reichelt; E. Nembach

    2007-01-01

    The feasibility of accurately measuring the size and the volume fraction of nanoscale plate-shaped precipitates by atomic force microscopy (AFM) has been explored. For quantitative evaluations their unhandy geometry is conveniently described by superellipsoids. The experimental alloy Ni69Co9Al18Ti4 served as a model system: plate-shaped disordered ?-precipitates form in the L12 long-range ordered ??-matrix. The results obtained by AFM are compared

  4. Immuno-electron microscopy of primary cell cultures from genetically modified animals in liquid by atmospheric scanning electron microscopy.

    PubMed

    Kinoshita, Takaaki; Mori, Yosio; Hirano, Kazumi; Sugimoto, Shinya; Okuda, Ken-ichi; Matsumoto, Shunsuke; Namiki, Takeshi; Ebihara, Tatsuhiko; Kawata, Masaaki; Nishiyama, Hidetoshi; Sato, Mari; Suga, Mitsuo; Higashiyama, Kenichi; Sonomoto, Kenji; Mizunoe, Yoshimitsu; Nishihara, Shoko; Sato, Chikara

    2014-04-01

    High-throughput immuno-electron microscopy is required to capture the protein-protein interactions realizing physiological functions. Atmospheric scanning electron microscopy (ASEM) allows in situ correlative light and electron microscopy of samples in liquid in an open atmospheric environment. Cells are cultured in a few milliliters of medium directly in the ASEM dish, which can be coated and transferred to an incubator as required. Here, cells were imaged by optical or fluorescence microscopy, and at high resolution by gold-labeled immuno-ASEM, sometimes with additional metal staining. Axonal partitioning of neurons was correlated with specific cytoskeletal structures, including microtubules, using primary-culture neurons from wild type Drosophila, and the involvement of ankyrin in the formation of the intra-axonal segmentation boundary was studied using neurons from an ankyrin-deficient mutant. Rubella virus replication producing anti-double-stranded RNA was captured at the host cell's plasma membrane. Fas receptosome formation was associated with clathrin internalization near the surface of primitive endoderm cells. Positively charged Nanogold clearly revealed the cell outlines of primitive endoderm cells, and the cell division of lactic acid bacteria. Based on these experiments, ASEM promises to allow the study of protein interactions in various complexes in a natural environment of aqueous liquid in the near future. PMID:24564988

  5. New tools for comparing microscopy images: quantitative analysis of cell types in Bacillus subtilis.

    PubMed

    van Gestel, Jordi; Vlamakis, Hera; Kolter, Roberto

    2015-02-15

    Fluorescence microscopy is a method commonly used to examine individual differences between bacterial cells, yet many studies still lack a quantitative analysis of fluorescence microscopy data. Here we introduce some simple tools that microbiologists can use to analyze and compare their microscopy images. We show how image data can be converted to distribution data. These data can be subjected to a cluster analysis that makes it possible to objectively compare microscopy images. The distribution data can further be analyzed using distribution fitting. We illustrate our methods by scrutinizing two independently acquired data sets, each containing microscopy images of a doubly labeled Bacillus subtilis strain. For the first data set, we examined the expression of srfA and tapA, two genes which are expressed in surfactin-producing and matrix-producing cells, respectively. For the second data set, we examined the expression of eps and tapA; these genes are expressed in matrix-producing cells. We show that srfA is expressed by all cells in the population, a finding which contrasts with a previously reported bimodal distribution of srfA expression. In addition, we show that eps and tapA do not always have the same expression profiles, despite being expressed in the same cell type: both operons are expressed in cell chains, while single cells mainly express eps. These findings exemplify that the quantification and comparison of microscopy data can yield insights that otherwise would go unnoticed. PMID:25448819

  6. High sensitivity piezomagnetic force microscopy for quantitative probing of magnetic materials at the nanoscale.

    PubMed

    Chen, Qian Nataly; Ma, Feiyue; Xie, Shuhong; Liu, Yuanming; Proksch, Roger; Li, Jiangyu

    2013-07-01

    Accurate scanning probing of magnetic materials at the nanoscale is essential for developing and characterizing magnetic nanostructures, yet quantitative analysis is difficult using the state of the art magnetic force microscopy, and has limited spatial resolution and sensitivity. In this communication, we develop a novel piezomagnetic force microscopy (PmFM) technique, with the imaging principle based on the detection of magnetostrictive response excited by an external magnetic field. In combination with the dual AC resonance tracking (DART) technique, the contact stiffness and energy dissipation of the samples can be simultaneously mapped along with the PmFM phase and amplitude, enabling quantitative probing of magnetic materials and structures at the nanoscale with high sensitivity and spatial resolution. PmFM has been applied to probe magnetic soft discs and cobalt ferrite thin films, demonstrating it as a powerful tool for a wide range of magnetic materials. PMID:23720016

  7. Scanning electron microscopy of cristispira species in chesapeake bay oysters.

    PubMed

    Tall, B D; Nauman, R K

    1981-08-01

    Scanning electron microscopy was employed to observe the physical interactions between Cristispira spp. and the crystalline style of the Chesapeake Bay oyster (Crassostrea virginica Gmelin 1791). Cristispira organisms were found associated with both the inner and outer layers of the posterior two-thirds of the style. The spirochetes possessed blunt-tipped ends, a cell diameter range of 0.6 to 0.8 mum, and distended spirochetal envelopes which followed the contour of the cells. Transmission electron microscopy showed that the distension of the envelope was probably due to the containment of numerous axial filaments. In addition, they were found to possess two distinct spiral shapes which were dependent on whether their location was inside or on the surface of the style. PMID:16345832

  8. Quantitative measurement of in-plane cantilever torsion for calibrating lateral piezoresponse force microscopy.

    SciTech Connect

    Choi, H.; Hong, S.; No, K. (Materials Science Division); (Korea Adv. Inst. Sci. Tech.)

    2011-01-01

    A simple quantitative measurement procedure of in-plane cantilever torsion for calibrating lateral piezoresponse force microscopy is presented. This technique enables one to determine the corresponding lateral inverse optical lever sensitivity (LIOLS) of the cantilever on the given sample. Piezoelectric coefficient, d{sub 31} of BaTiO{sub 3} single crystal (-81.62 {+-} 40.22 pm/V) which was calculated using the estimated LIOLS was in good agreement with the reported value in literature.

  9. Cathodoluminescence of brown diamonds as observed by transmission electron microscopy

    Microsoft Academic Search

    R. J. Graham; Peter R. Buseck

    1994-01-01

    Cathodoluminescing features in brown diamonds correlate with the crystalline microstructure as observed by transmission electron microscopy. We identified distinctive emissions at 415.3, 425, 491.3 and 525 nm. The first two correlate with the so-called N3 and band-A emissions, while the last correlates with what is called a strain-broadened H3 band. The N3 emission is associated with stacking faults on {111}

  10. Characterization of nanomaterials in food by electron microscopy

    Microsoft Academic Search

    Agnieszka Dudkiewicz; Karen Tiede; Katrin Loeschner; Louise Helene Soegaard Jensen; Eric Jensen; Rafal Wierzbicki; Alistair B. A. Boxall; Kristian Molhave

    2011-01-01

    Engineered nanomaterials (ENMs) are increasingly being used in the food industry. In order to assess the efficacy and the risks of these materials, it is essential to have access to methods that not only detect the nanomaterials, but also provide information on the characteristics of the materials (e.g., size and shape).This review presents an overview of electron microscopy (EM)-based methods

  11. Microanalysis of ambient particles from Lexington, KY, by electron microscopy

    Microsoft Academic Search

    Yuanzhi Chen; Naresh Shah; Frank E. Huggins; Gerald P. Huffman

    2006-01-01

    Analytical transmission electron microscopy has been used for in-depth characterization of the individual submicron (physical size<1?m) particulate matter (PM) from the urban atmosphere of Lexington, Kentucky, USA. Carbonaceous particles and sulfur-bearing particles dominate the PM samples on a particle count basis. Soot aggregates are the major form of carbonaceous particles. Organic-type and biogenic carbonaceous particles are also observed and exhibit

  12. Progress towards critical dimension low vacuum scanning electron microscopy

    Microsoft Academic Search

    Vasiliki Tileli

    2009-01-01

    Low vacuum scanning electron microscopy (LVSEM) is proposed and evaluated for next generation Critical Dimension (CD) metrology. Its ability to control charging artifacts and hydrocarbon contamination in order to obtain high signal-to-noise ratio, high resolution image data from insulating materials make the technology an excellent match for the increased use of high-k dielectrics and shrinking feature size in the semiconductor

  13. Fixation methods for electron microscopy of human and other liver

    PubMed Central

    Wisse, Eddie; Braet, Filip; Duimel, Hans; Vreuls, Celien; Koek, Ger; Olde Damink, Steven WM; van den Broek, Maartje AJ; De Geest, Bart; Dejong, Cees HC; Tateno, Chise; Frederik, Peter

    2010-01-01

    For an electron microscopic study of the liver, expertise and complicated, time-consuming processing of hepatic tissues and cells is needed. The interpretation of electron microscopy (EM) images requires knowledge of the liver fine structure and experience with the numerous artifacts in fixation, embedding, sectioning, contrast staining and microscopic imaging. Hence, the aim of this paper is to present a detailed summary of different methods for the preparation of hepatic cells and tissue, for the purpose of preserving long-standing expertise and to encourage new investigators and clinicians to include EM studies of liver cells and tissue in their projects. PMID:20556830

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

    NASA Astrophysics Data System (ADS)

    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. 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. Electron microscopy study of antioxidant interaction with bacterial cells

    NASA Astrophysics Data System (ADS)

    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.

  16. Lamin B distribution and association with peripheral chromatin revealed by optical sectioning and electron microscopy tomography

    PubMed Central

    1993-01-01

    We have used a combination of immunogold staining, optical sectioning light microscopy, intermediate voltage electron microscopy, and EM tomography to examine the distribution of lamin B over the nuclear envelope of CHO cells. Apparent inconsistencies between previously published light and electron microscopy studies of nuclear lamin staining were resolved. At light microscopy resolution, an apparent open fibrillar network is visualized. Colocalization of lamin B and nuclear pores demonstrates that these apparent fibrils, separated by roughly 0.5 micron, are anti-correlated with the surface distribution of nuclear pores; pore clusters lie between or adjacent to regions of heavy lamin B staining. Examination at higher, EM resolution reveals that this apparent lamin B network does not correspond to an actual network of widely spaced, discrete bundles of lamin filaments. Rather it reflects a quantitative variation in lamin staining over a roughly 0.5-micron size scale, superimposed on a more continuous but still complex distribution of lamin filaments, spatially heterogeneous on a 0.1-0.2-micron size scale. Interestingly, lamin B staining at this higher resolution is highly correlated to the underlying chromatin distribution. Heavy concentrations of lamin B directly "cap" the surface of envelope associated, large-scale chromatin domains. PMID:8276889

  17. Quantitative Vibrational Imaging by Hyperspectral Stimulated Raman Scattering Microscopy and Multivariate Curve Resolution Analysis

    PubMed Central

    Zhang, Delong; Wang, Ping; Slipchenko, Mikhail N.; Ben-Amotz, Dor; Weiner, Andrew M.; Cheng, Ji-Xin

    2013-01-01

    Spectroscopic imaging has been an increasingly critical approach for unveiling specific molecules in biological environments. Towards this goal, we demonstrate hyperspectral stimulated Raman loss (SRL) imaging by intra-pulse spectral scanning through a femtosecond pulse shaper. The hyperspectral stack of SRL images is further analyzed by a multivariate curve resolution (MCR) method to reconstruct quantitative concentration images for each individual component and retrieve the corresponding vibrational Raman spectra. Using these methods, we demonstrate quantitative mapping of dimethyl sulfoxide concentration in aqueous solutions and in fat tissue. Moreover, MCR is performed on SRL images of breast cancer cells to generate maps of principal chemical components along with their respective vibrational spectra. These results show the great capability and potential of hyperspectral SRL microscopy for quantitative imaging of complicated biomolecule mixtures through resolving overlapped Raman bands. PMID:23198914

  18. Advances in quantitative nanoscale subsurface imaging by mode-synthesizing atomic force microscopy

    SciTech Connect

    Vitry, P.; Bourillot, E.; Plassard, C.; Lacroute, Y.; Lesniewska, E. [ICB, UMR CNRS 6303 CNRS-University of Bourgogne, Dijon F-21078 (France); Tetard, L. [Nanoscience Technology Center, University of Central Florida, Orlando, Florida 32826 (United States)

    2014-08-04

    This paper reports on advances toward quantitative non-destructive nanoscale subsurface investigation of a nanofabricated sample based on mode synthesizing atomic force microscopy with heterodyne detection, addressing the need to correlate the role of actuation frequencies of the probe f{sub p} and the sample f{sub s} with depth resolution for 3D tomography reconstruction. Here, by developing a simple model and validating the approach experimentally through the study of the nanofabricated calibration depth samples consisting of buried metallic patterns, we demonstrate avenues for quantitative nanoscale subsurface imaging. Our findings enable the reconstruction of the sample depth profile and allow high fidelity resolution of the buried nanostructures. Non-destructive quantitative nanoscale subsurface imaging offers great promise in the study of the structures and properties of complex systems at the nanoscale.

  19. Visualizing Gold Nanoparticle Uptake in Live Cells with Liquid Scanning Transmission Electron Microscopy

    PubMed Central

    2011-01-01

    The intracellular uptake of 30 nm diameter gold nanoparticles (Au-NPs) was studied at the nanoscale in pristine eukaryotic cells. Live COS-7 cells were maintained in a microfluidic chamber and imaged using scanning transmission electron microscopy. A quantitative image analysis showed that Au-NPs bound to the membranes of vesicles, possibly lysosomes, and occupied 67% of the available surface area. The vesicles accumulated to form a micrometer-sized cluster after 24 h of incubation. Two clusters were analyzed and found to consist of 117 ± 9 and 164 ± 4 NP-filled vesicles. PMID:21410218

  20. The use of light- and electron microscopy for studies on the cell- and molecular biology of parasites and parasitic diseases.

    PubMed

    Hehl, A B; Hemphill, A

    2006-09-01

    Lightmicroscopical (LM) and electron microscopi cal (EM) techniques, have had a major influence on the development and direction of cell biology, and particularly also on the investigation of complex host-parasite relationships. Earlier, microscopy has been rather descriptive, but new technical and scientific advances have changed the situation. Microscopy has now become analytical, quantitative and three-dimensional, with greater emphasis on analysis of live cells with fluorescent markers. The new or improved techniques that have become available include immunocytochemistry using immunogold labeling techniques or fluorescent probes, cryopreservation and cryosectioning, in situ hybridization, fluorescent reporters for subcellular localization, micro-analytical methods for elemental distribution, confocal laser scanning microscopy, scanning tunneling microscopy and live-imaging. Taken together, these tools are providing both researchers and students with a novel and multidimensional view of the intricate biological processes during parasite development in the host. PMID:17024976

  1. 4D multiple-cathode ultrafast electron microscopy

    PubMed Central

    Baskin, John Spencer; Liu, Haihua; Zewail, Ahmed H.

    2014-01-01

    Four-dimensional multiple-cathode ultrafast electron microscopy is developed to enable the capture of multiple images at ultrashort time intervals for a single microscopic dynamic process. The dynamic process is initiated in the specimen by one femtosecond light pulse and probed by multiple packets of electrons generated by one UV laser pulse impinging on multiple, spatially distinct, cathode surfaces. Each packet is distinctly recorded, with timing and detector location controlled by the cathode configuration. In the first demonstration, two packets of electrons on each image frame (of the CCD) probe different times, separated by 19 picoseconds, in the evolution of the diffraction of a gold film following femtosecond heating. Future elaborations of this concept to extend its capabilities and expand the range of applications of 4D ultrafast electron microscopy are discussed. The proof-of-principle demonstration reported here provides a path toward the imaging of irreversible ultrafast phenomena of materials, and opens the door to studies involving the single-frame capture of ultrafast dynamics using single-pump/multiple-probe, embedded stroboscopic imaging. PMID:25006261

  2. 4D multiple-cathode ultrafast electron microscopy.

    PubMed

    Baskin, John Spencer; Liu, Haihua; Zewail, Ahmed H

    2014-07-22

    Four-dimensional multiple-cathode ultrafast electron microscopy is developed to enable the capture of multiple images at ultrashort time intervals for a single microscopic dynamic process. The dynamic process is initiated in the specimen by one femtosecond light pulse and probed by multiple packets of electrons generated by one UV laser pulse impinging on multiple, spatially distinct, cathode surfaces. Each packet is distinctly recorded, with timing and detector location controlled by the cathode configuration. In the first demonstration, two packets of electrons on each image frame (of the CCD) probe different times, separated by 19 picoseconds, in the evolution of the diffraction of a gold film following femtosecond heating. Future elaborations of this concept to extend its capabilities and expand the range of applications of 4D ultrafast electron microscopy are discussed. The proof-of-principle demonstration reported here provides a path toward the imaging of irreversible ultrafast phenomena of materials, and opens the door to studies involving the single-frame capture of ultrafast dynamics using single-pump/multiple-probe, embedded stroboscopic imaging. PMID:25006261

  3. Observation of degradation processes of Al electrodes in organic electroluminescence devices by electroluminescence microscopy, atomic force microscopy, scanning electron microscopy, and Auger electron spectroscopy

    Microsoft Academic Search

    L. M. Do; E. M. Han; Y. Niidome; M. Fujihira; T. Kanno; S. Yoshida; A. Maeda; A. J. Ikushima

    1994-01-01

    Degradation of top electrodes is one of the most important factors to determine the lifetimes of organic electroluminescence (EL) devices. An organic EL device (indium thin oxide (ITO\\/N,N'-diphenyl-N,N'-bis(3-methylphenyl)-(1,1'-biphenyl)-4,4'-diamine (TPD)\\/tris(8-hydroxy-quinoline)aluminum (Al q(sub 3))\\/Al) was prepared and a morphological change of the Al top electrode was observed during and\\/or after applying voltage by atomic force microscopy and scanning electron microscopy (SEM). The

  4. Application of environmental scanning electron microscopy to determine biological surface structure

    Microsoft Academic Search

    S. E. KIRK; J. N. SKEPPER; A. M. DONALD

    2009-01-01

    Summary The use of environmental scanning electron microscopy in biology is growing as more becomes understood about the advantages and limitations of the technique. These are discussed and we include new evidence about the effect of environmental scanning electron microscopy imaging on the viabilityofmammaliancells.Weshowthatalthoughspecimen preparation for high-vacuum scanning electron microscopy introduces some artefacts, there are also challenges in the use

  5. Scanning electron microscopy of cells and tissues under fully hydrated conditions

    Microsoft Academic Search

    Stephan Thiberge; Amotz Nechushtan; David Sprinzak; Opher Gileadi; Vered Behar; Ory Zik; Yehuda Chowers; Shulamit Michaeli; Joseph Schlessinger; Elisha Moses

    2004-01-01

    A capability for scanning electron microscopy of wet biological specimens is presented. A membrane that is transparent to electrons protects the fully hydrated sample from the vacuum. The result is a hybrid technique combining the ease of use and ability to see into cells of optical microscopy with the higher resolution of electron microscopy. The resolution of low-contrast materials is

  6. In-Situ Imaging of Langmuir Films using Environmental Scanning Electron Microscopy

    Microsoft Academic Search

    Aline Miller

    2002-01-01

    Environmental scanning electron microscopy (ESEM) has been applied to image the organization of spread films at the air-water interface directly. This recent extension of conventional scanning electron microscopy permits the resolution of electron microscopy to be applied to insulated and hydrated samples maintained in their natural state. We demonstrate the great potential of this technique by in-situ imaging of both

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

    PubMed

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

    2012-01-01

    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. PMID:22223801

  8. Time resolved electron microscopy for in situ experiments

    NASA Astrophysics Data System (ADS)

    Campbell, Geoffrey H.; McKeown, Joseph T.; Santala, Melissa K.

    2014-12-01

    Transmission electron microscopy has functioned for decades as a platform for in situ observation of materials and processes with high spatial resolution. Yet, the dynamics often remain elusive, as they unfold too fast to discern at these small spatial scales under traditional imaging conditions. Simply shortening the exposure time in hopes of capturing the action has limitations, as the number of electrons will eventually be reduced to the point where noise overtakes the signal in the image. Pulsed electron sources with high instantaneous current have successfully shortened exposure times (thus increasing the temporal resolution) by about six orders of magnitude over conventional sources while providing the necessary signal-to-noise ratio for dynamic imaging. We describe here the development of this new class of microscope and the principles of its operation, with examples of its application to problems in materials science.

  9. Microbial Nanowire Electronic Structure Probed by Scanning Tunneling Microscopy

    NASA Astrophysics Data System (ADS)

    Veazey, Joshua P.; Lampa-Pastirk, Sanela; Reguera, Gemma; Tessmer, Stuart H.

    2010-03-01

    Complex molecules produced by living organisms provide laboratories for interesting physical properties. The study of such interesting physics, likewise, gives new insight into intriguing biological processes. We have studied the pilus nanowires expressed by the bacterium, Geobacter sulfurreducens, using high resolution scanning tunneling microscopy (STM). G. sulfurreducens is a metal reducing bacterium that has evolved electrically conductive pili to efficiently transfer electrons across large distances.footnotetextG. Reguera, K.D. McCarthy, T. Mehta, J.S. Nicoll, M.T. Tuominen, and D.R. Lovley, Nature 435, 1098 (2005) Here we employ the electronic sensitivity of STM to resolve the molecular substructure and the local electronic density of states (LDOS) along the nanowire, in an effort to elucidate the mechanism of conduction. We observe LDOS dependent upon the location of the tip above the nanowire.

  10. Correlative fluorescence microscopy and scanning transmission electron microscopy of quantum-dot-labeled proteins in whole cells in liquid.

    PubMed

    Dukes, Madeline J; Peckys, Diana B; de Jonge, Niels

    2010-07-27

    Correlative fluorescence microscopy and transmission electron microscopy (TEM) is a state-of-the-art microscopy methodology to study cellular function, combining the functionality of light microscopy with the high resolution of electron microscopy. However, this technique involves complex sample preparation procedures due to its need for either thin sections or frozen samples for TEM imaging. Here, we introduce a novel correlative approach capable of imaging whole eukaryotic cells in liquid with fluorescence microscopy and with scanning transmission electron microscopy (STEM); there is no additional sample preparation necessary for the electron microscopy. Quantum dots (QDs) were bound to epidermal growth factor (EGF) receptors of COS7 fibroblast cells. Fixed whole cells in saline water were imaged with fluorescence microscopy and subsequently with STEM. The STEM images were correlated with fluorescence images of the same cellular regions. QDs of dimensions 7x12 nm were visible in a 5 microm thick layer of saline water, consistent with calculations. A spatial resolution of 3 nm was achieved on the QDs. PMID:20550177

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

    PubMed

    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. PMID:20869529

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

    PubMed

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

    2014-08-01

    Correlative light-electron microscopy of cells in a natural environment of aqueous liquid facilitates high-throughput observation of protein complex formation. ASEM allows the inverted SEM to observe the wet sample from below, while an optical microscope observes it from above quasi-simultaneously. The disposable ASEM dish with a silicon nitride (SiN) film window can be coated variously to realize the primary-culture of substrate-sensitive cells in a few milliliters of culture medium in a stable incubator environment. Neuron differentiation, neural networking, proplatelet-formation and phagocytosis were captured by optical or fluorescence microscopy, and imaged at high resolution by gold-labeled immuno-ASEM with/without metal staining. Fas expression on the cell surface was visualized, correlated to the spatial distribution of F-actin. Axonal partitioning was studied using primary-culture neurons, and presynaptic induction by GluR?2-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. PMID:24216127

  13. High resolution electron microscopy and spectroscopy of ferritin in thin window liquid cells

    NASA Astrophysics Data System (ADS)

    Wang, Canhui; Qiao, Qiao; Shokuhfar, Tolou; Klie, Robert

    2014-03-01

    In-situ transmission electron microscopy (TEM) has seen a dramatic increase in interest in recent years with the commercial development of liquid and gas stages. High-resolution TEM characterization of samples in a liquid environment remains limited by radiation damage and loss of resolution due to the thick window-layers required by the in-situ stages. We introduce thin-window static-liquid cells that enable sample imaging with atomic resolution and electron energy-loss (EEL) spectroscopy with 1.3 nm resolution. Using this approach, atomic and electronic structures of biological samples such as ferritin is studied via in-situ transmission electron microscopy experiments. Ferritin in solution is encapsulated using the static liquid cells with reduced window thickness. The integrity of the thin window liquid cell is maintained by controlling the electron dose rate. Radiation damage of samples, such as liquid water and protein, is quantitatively studied to allow precision control of radiation damage level within the liquid cells. Biochemical reactions, such as valence change of the iron in a functioning ferritin, is observed and will be quantified. Relevant biochemical activity: the release and uptake of Fe atoms through the channels of ferritin protein shell is also imaged at atomic resolution. This work is funded by Michigan Technological University. The UIC JEOL JEM-ARM200CF is supported by an MRI-R2 grant from the National Science Foundation (Grant No. DMR-0959470).

  14. Installation of electric field electron beam blanker in high-resolution transmission electron microscopy

    SciTech Connect

    Hayashida, Misa; Kimura, Yoshihide; Taniguchi, Yoshifumi; Otsuka, Masayuki; Takai, Yoshizo [Department of Material and Life Science, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871 (Japan); Hitachi High-Technologies Corporation, 882 Ichige, Hitachinaka, Ibaraki 312-8504 (Japan); Department of Material and Life Science, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871 (Japan)

    2006-11-15

    We have newly installed an electric field electron beam blanker in a transmission electron microscopy, which chops an electron beam very quickly without the effect of hysteresis. The electric field, which is generated by the electron beam blanker, deflects the electron beam, and the electron beam is intercepted by an aperture. The response time of the beam blanker is 50 {mu}s. Therefore, a very short pulsed electron beam enables a charge-coupled device camera to directly expose an electron beam spot or diffraction pattern. Moreover, we measured the response of a deflector coil, which is usually used as an electron beam blanker, using our electron beam blanker. Our beam blanker will become a key component in a computer-assisted minimal dose system, which enables us to reduce the electron dose of the sample.

  15. High bandwidth secondary electron detection in variable pressure scanning electron microscopy using a Frisch grid

    Microsoft Academic Search

    S. W. Morgan; M. R. Phillips

    2008-01-01

    The bandwidth and contrast of secondary electron (SE) images obtained using variable pressure scanning electron microscopy are enhanced when a grounded Frisch grid is placed between the SE detecting anode and the negatively biased stage. The improvement in SE image quality occurs as a consequence of the grounded Frisch grid electrostatically screening the 'slow' induced ion current signal, generated below

  16. High bandwidth secondary electron detection in variable pressure scanning electron microscopy using a Frisch grid

    Microsoft Academic Search

    S W Morgan; M R Phillips

    2008-01-01

    The bandwidth and contrast of secondary electron (SE) images obtained using variable pressure scanning electron microscopy are enhanced when a grounded Frisch grid is placed between the SE detecting anode and the negatively biased stage. The improvement in SE image quality occurs as a consequence of the grounded Frisch grid electrostatically screening the ‘slow’ induced ion current signal, generated below

  17. Quantitative phase retrieval in X-ray Zernike phase contrast microscopy.

    PubMed

    Chen, Heng; Wang, Zhili; Gao, Kun; Hou, Qiyue; Wang, Dajiang; Wu, Ziyu

    2015-07-01

    In recent years, increasing attention has been devoted to X-ray phase contrast imaging, since it can provide high-contrast images by using phase variations. Among the different existing techniques, Zernike phase contrast microscopy is one of the most popular phase-sensitive techniques for investigating the fine structure of the sample at high spatial resolution. In X-ray Zernike phase contrast microscopy, the image contrast is indeed a mixture of absorption and phase contrast. Therefore, this technique just provides qualitative information on the object, which makes the interpretation of the image difficult. In this contribution, an approach is proposed for quantitative phase retrieval in X-ray Zernike phase contrast microscopy. By shifting the phase of the direct light by ?/2 and 3?/2, two images of the same object are measured successively. The phase information of the object can then be quantitatively retrieved by a proper combination of the measured images. Numerical experiments were carried out and the results confirmed the feasibility of the proposed method. It is expected that the proposed method will find widespread applications in biology, materials science and so on. PMID:26134811

  18. Digital Holographic Microscopy: Quantitative Phase Imaging and Applications in Live Cell Analysis

    NASA Astrophysics Data System (ADS)

    Kemper, Björn; Langehanenberg, Patrik; Kosmeier, Sebastian; Schlichthaber, Frank; Remmersmann, Christian; von Bally, Gert; Rommel, Christina; Dierker, Christian; Schnekenburger, Jürgen

    The analysis of complex processes in living cells creates a high demand for fast and label-free methods for online monitoring. Widely used fluorescence methods require specific labeling and are often restricted to chemically fixated samples. Thus, methods that offer label-free and minimally invasive detection of live cell processes and cell state alterations are of particular interest. In combination with light microscopy, digital holography provides label-free, multi-focus quantitative phase imaging of living cells. In overview, several methods for digital holographic microscopy (DHM) are presented. First, different experimental setups for the recording of digital holograms and the modular integration of DHM into common microscopes are described. Then the numerical processing of digitally captured holograms is explained. This includes the description of spatial and temporal phase shifting techniques, spatial filtering based reconstruction, holographic autofocusing, and the evaluation of self-interference holograms. Furthermore, the usage of partial coherent light and multi-wavelength approaches is discussed. Finally, potentials of digital holographic microscopy for quantitative cell imaging are illustrated by results from selected applications. It is shown that DHM can be used for automated tracking of migrating cells and cell thickness monitoring as well as for refractive index determination of cells and particles. Moreover, the use of DHM for label-free analysis in fluidics and micro-injection monitoring is demonstrated. The results show that DHM is a highly relevant method that allows novel insights in dynamic cell biology, with applications in cancer research and for drugs and toxicity testing.

  19. Quantitative high-resolution microscopy on a suspended chain of gold atoms

    Microsoft Academic Search

    H. Koizumi; Y. Oshima; Y. Kondo; K. Takayanagi

    2001-01-01

    High-resolution electron microscope images of a suspended gold chain were analyzed quantitatively. The images of the suspended gold chain were recorded on videotapes, during in situ observation in an ultra-high-vacuum electron microscope. The chain consisted of four gold atoms free from any substrate. Image simulation verified that the gold chain has a center-top geometry. The simulation also showed that the

  20. Quantitative sub-surface and non-contact imaging using scanning microwave microscopy

    NASA Astrophysics Data System (ADS)

    Gramse, Georg; Brinciotti, Enrico; Lucibello, Andrea; Patil, Samadhan B.; Kasper, Manuel; Rankl, Christian; Giridharagopal, Rajiv; Hinterdorfer, Peter; Marcelli, Romolo; Kienberger, Ferry

    2015-03-01

    The capability of scanning microwave microscopy for calibrated sub-surface and non-contact capacitance imaging of silicon (Si) samples is quantitatively studied at broadband frequencies ranging from 1 to 20 GHz. Calibrated capacitance images of flat Si test samples with varying dopant density (1015–1019 atoms cm?3) and covered with dielectric thin films of SiO2 (100–400 nm thickness) are measured to demonstrate the sensitivity of scanning microwave microscopy (SMM) for sub-surface imaging. Using standard SMM imaging conditions the dopant areas could still be sensed under a 400 nm thick oxide layer. Non-contact SMM imaging in lift-mode and constant height mode is quantitatively demonstrated on a 50 nm thick SiO2 test pad. The differences between non-contact and contact mode capacitances are studied with respect to the main parameters influencing the imaging contrast, namely the probe tip diameter and the tip–sample distance. Finite element modelling was used to further analyse the influence of the tip radius and the tip–sample distance on the SMM sensitivity. The understanding of how the two key parameters determine the SMM sensitivity and quantitative capacitances represents an important step towards its routine application for non-contact and sub-surface imaging.

  1. Interferometric time-stretch microscopy for ultrafast quantitative cellular and tissue imaging at 1 ?m.

    PubMed

    Lau, Andy K S; Wong, Terence T W; Ho, Kenneth K Y; Tang, Matthew T H; Chan, Antony C S; Wei, Xiaoming; Lam, Edmund Y; Shum, Ho Cheung; Wong, Kenneth K Y; Tsia, Kevin K

    2014-01-01

    Quantitative phase imaging (QPI) has been proven to be a powerful tool for label-free characterization of biological specimens. However, the imaging speed, largely limited by the image sensor technology, impedes its utility in applications where high-throughput screening and efficient big-data analysis are mandated. We here demonstrate interferometric time-stretch (iTS) microscopy for delivering ultrafast quantitative phase cellular and tissue imaging at an imaging line-scan rate >20 MHz—orders-of-magnitude faster than conventional QPI. Enabling an efficient time-stretch operation in the 1-?m wavelength window, we present an iTS microscope system for practical ultrafast QPI of fixed cells and tissue sections, as well as ultrafast flowing cells (at a flow speed of up to 8 m?s). To the best of our knowledge, this is the first time that time-stretch imaging could reveal quantitative morphological information of cells and tissues with nanometer precision. As many parameters can be further extracted from the phase and can serve as the intrinsic biomarkers for disease diagnosis, iTS microscopy could find its niche in high-throughput and high-content cellular assays (e.g., imaging flow cytometry) as well as tissue refractometric imaging (e.g., whole-slide imaging for digital pathology). PMID:24983913

  2. Quantitative sub-surface and non-contact imaging using scanning microwave microscopy.

    PubMed

    Gramse, Georg; Brinciotti, Enrico; Lucibello, Andrea; Patil, Samadhan B; Kasper, Manuel; Rankl, Christian; Giridharagopal, Rajiv; Hinterdorfer, Peter; Marcelli, Romolo; Kienberger, Ferry

    2015-03-27

    The capability of scanning microwave microscopy for calibrated sub-surface and non-contact capacitance imaging of silicon (Si) samples is quantitatively studied at broadband frequencies ranging from 1 to 20 GHz. Calibrated capacitance images of flat Si test samples with varying dopant density (10(15)-10(19) atoms cm(-3)) and covered with dielectric thin films of SiO2 (100-400 nm thickness) are measured to demonstrate the sensitivity of scanning microwave microscopy (SMM) for sub-surface imaging. Using standard SMM imaging conditions the dopant areas could still be sensed under a 400 nm thick oxide layer. Non-contact SMM imaging in lift-mode and constant height mode is quantitatively demonstrated on a 50 nm thick SiO2 test pad. The differences between non-contact and contact mode capacitances are studied with respect to the main parameters influencing the imaging contrast, namely the probe tip diameter and the tip-sample distance. Finite element modelling was used to further analyse the influence of the tip radius and the tip-sample distance on the SMM sensitivity. The understanding of how the two key parameters determine the SMM sensitivity and quantitative capacitances represents an important step towards its routine application for non-contact and sub-surface imaging. PMID:25751635

  3. Correlative light and electron microscopy imaging of autophagy in a zebrafish infection model.

    PubMed

    Hosseini, Rohola; Lamers, Gerda Em; Hodzic, Zlatan; Meijer, Annemarie H; Schaaf, Marcel Jm; Spaink, Herman P

    2014-10-01

    High-resolution imaging of autophagy has been used intensively in cell culture studies, but so far it has been difficult to visualize this process in detail in whole animal models. In this study we present a versatile method for high-resolution imaging of microbial infection in zebrafish larvae by injecting pathogens into the tail fin. This allows visualization of autophagic compartments by light and electron microscopy, which makes it possible to correlate images acquired by the 2 techniques. Using this method we have studied the autophagy response against Mycobacterium marinum infection. We show that mycobacteria during the progress of infection are frequently associated with GFP-Lc3-positive vesicles, and that 2 types of GFP-Lc3-positive vesicles were observed. The majority of these vesicles were approximately 1 ?m in size and in close vicinity of bacteria, and a smaller number of GFP-Lc3-positive vesicles was larger in size and were observed to contain bacteria. Quantitative data showed that these larger vesicles occurred significantly more in leukocytes than in other cell types, and that approximately 70% of these vesicles were positive for a lysosomal marker. Using electron microscopy, it was found that approximately 5% of intracellular bacteria were present in autophagic vacuoles and that the remaining intracellular bacteria were present in phagosomes, lysosomes, free inside the cytoplasm or occurred as large aggregates. Based on correlation of light and electron microscopy images, it was shown that GFP-Lc3-positive vesicles displayed autophagic morphology. This study provides a new approach for injection of pathogens into the tail fin, which allows combined light and electron microscopy imaging in vivo and opens new research directions for studying autophagy process related to infectious diseases. PMID:25126731

  4. Etude quantitative et en microscopie electronique du nerf dans sept cas de neuropathie sensitive idiopathique sporadique

    Microsoft Academic Search

    A. Guimaraes; J. J. Hauw; R. Escourolle

    1979-01-01

    An electron microscope study and quantitation of myelinated and unmyelinated fibers of seven nerve biopsies performed in sporadic cases of idiopathic sensory neuropathy is reported. The number of myelinated fibers is markedly decreased or absent in every case. On the contrary, the unmyelinated fiber numbers are normal or increased. In most cases, the small diameter myelinated and unmyelinated fibers proportions

  5. Catching HIV ‘in the act’ with 3D electron microscopy

    PubMed Central

    Earl, Lesley A.; Lifson, Jeffrey D.; Subramaniam, Sriram

    2013-01-01

    The development of a safe, effective vaccine to prevent human immunodeficiency virus (HIV) infection is a key step for controlling the disease on a global scale. However, many aspects of HIV biology make vaccine design problematic, including the sequence diversity and structural variability of the surface envelope glycoproteins and the poor accessibility of neutralization-sensitive epitopes on the virus. In this review, we discuss recent progress in understanding HIV in a structural context using emerging tools in 3D electron microscopy, and outline how some of these advances could be important for a better understanding of mechanisms of viral entry and for vaccine design. PMID:23850373

  6. Visualization of Ceramide Channels by Transmission Electron Microscopy

    PubMed Central

    Samanta, Soumya; Stiban, Johnny; Maugel, Timothy K.; Colombini, Marco

    2011-01-01

    Functional studies have shown that the sphingolipid, ceramide self-assembles in phospholipid membranes to form large channels capable of allowing proteins to cross the membrane. Here these channels are visualized by negative stain transmission electron microscopy. The images contain features consistent with stain-filled pores having a roughly circular profile. There is no indication of tilt and the results are consistent with the formation of right cylinders. The sizes of the pores range from 5 to 40 nm in diameter with an asymmetric distribution indicating no apparent upper size limit. The size distribution matches well with the distribution of sizes calculated from electrophysiological measurements. PMID:21255554

  7. Photoemission Electron Microscopy of a Plasmonic Silver Nanoparticle Trimer

    SciTech Connect

    Peppernick, Samuel J.; Joly, Alan G.; Beck, Kenneth M.; Hess, Wayne P.; Wang, Jinyong; Wang, Yi-Chung; Wei, Wei

    2013-07-01

    We present a combined experimental and theoretical study to investigate the spatial distribution of photoelectrons emitted from core-shell silver (Ag) nanoparticles. We use two-photon photoemission microscopy (2P-PEEM) to spatially resolve electron emission from a trimeric core-shell aggregate of triangular symmetry. Finite difference time domain (FDTD) simulations are performed to model the intensity distributions of the electromagnetic near-fields resulting from femtosecond (fs) laser excitation of localized surface plasmon oscillations in the triangular core-shell structure. We demonstrate that the predicted FDTD near-field intensity distribution reproduces the 2P-PEEM photoemission pattern.

  8. Cryogenic electron microscopy study of nanoemulsion formation from microemulsions.

    PubMed

    Lee, Han Seung; Morrison, Eric D; Frethem, Chris D; Zasadzinski, Joseph A; McCormick, Alon V

    2014-09-16

    We examine a process of preparing oil-in-water nanoemulsions by quenching (diluting and cooling) precursor microemulsions made with nonionic surfactants and a cosurfactant. The precursor microemulsion structure is varied by changing the concentration of the cosurfactant. Water-continuous microemulsions produce initial nanoemulsion structures that are small and simple, mostly unilamellar vesicles, but microemulsions that are not water-continuous produce initial nanoemulsion structures that are larger and multilamellar. Examination of these structures by cryo-electron microscopy supports the hypothesis that they are initially vesicular structures formed via lamellar intermediate structures, and that if the lamellar structures are too well ordered they fail to produce small simple structures. PMID:25141294

  9. Complementary Visualization of Mitotic Barley Chromatin by Field-Emission Scanning Electron Microscopy and Scanning Force Microscopy

    Microsoft Academic Search

    A. Schaper; M. Rößle; H. Formanek; T. M. Jovin; G. Wanner

    2000-01-01

    The surface structure of mitotic barley chromatin was studied by field-emission scanning electron microscopy (FESEM) and scanning force microscopy (SFM). Different stages of the cell cycle were accessible after a cell suspension was dropped onto a glass surface, chemical fixed, and critically point dried. Imaging was carried out with metal-coated specimen or uncoated specimen (only for SFM). The spatial contour

  10. Correlative video-light-electron microscopy of mobile organelles.

    PubMed

    Beznoussenko, Galina V; Mironov, Alexander A

    2015-01-01

    Correlative microscopy is a method when for the analysis of the very same cell or tissue area, several different methods of light microscopy (LM) and then electron microscopy (EM) are used consecutively. The combination of LM and EM allows researchers to study phenomena at a global scale and then to look for unique or rare events for their subsequent EM examination. Unfortunately, the observation of living cells under EM is still impossible. LM provides the possibility to examine quickly many live cells, whereas EM provides the high level of resolution. On the other side, the final goal of any morphological analysis of a biological sample, whether it is an organism, organ, tissue, cell, organelle, or molecule, is to get an averaged three-dimensional model of the structure examined and to determine the chemical composition of it. This chapter describes the methodology of imaging with the help of CVLEM. The guidelines presented herein enable researchers to analyze structure of organelles and to obtain the three-dimensional model of the structure examined, and in particular rare events captured by low-resolution imaging of a population or transient events captured by live imaging can now also be studied at high resolution by EM. PMID:25702127

  11. Spatially resolved quantitative mapping of thermomechanical properties and phase transition temperatures using scanning probe microscopy

    DOEpatents

    Jesse, Stephen; Kalinin, Sergei V; Nikiforov, Maxim P

    2013-07-09

    An approach for the thermomechanical characterization of phase transitions in polymeric materials (polyethyleneterephthalate) by band excitation acoustic force microscopy is developed. This methodology allows the independent measurement of resonance frequency, Q factor, and oscillation amplitude of a tip-surface contact area as a function of tip temperature, from which the thermal evolution of tip-surface spring constant and mechanical dissipation can be extracted. A heating protocol maintained a constant tip-surface contact area and constant contact force, thereby allowing for reproducible measurements and quantitative extraction of material properties including temperature dependence of indentation-based elastic and loss moduli.

  12. Double-tip piezoresponse force microscopy for quantitative measurement of the piezoelectric coefficient at the nanoscale

    NASA Astrophysics Data System (ADS)

    Pan, K.; Liu, Y. M.; Peng, J. L.; Liu, Y. Y.

    2013-12-01

    Since the rotational symmetry of an electric field induced by piezoresponse force microscopy (PFM) can be broken and tuned by a scanning probe microscope (SPM) using multiple tips, a double-tip PFM measurement method is proposed to quantitatively determine the piezoelectric coefficient d33 at the nanoscale, realized by modulating the spacing or voltage ratio between two SPM tips. Compared to the traditional PFM using a single SPM tip, the piezoelectric coefficient measured by the double-tip method agrees much better with the intrinsic value.

  13. Quantitative analysis on collagen morphology in aging skin based on multiphoton microscopy

    NASA Astrophysics Data System (ADS)

    Wu, Shulian; Li, Hui; Yang, Hongqin; Zhang, Xiaoman; Li, Zhifang; Xu, Shufei

    2011-04-01

    Multiphoton microscopy was employed for monitoring the structure changes of mouse dermis collagen in the intrinsic- or the extrinsic-age-related processes in vivo. The characteristics of textures in different aging skins were uncovered by fast Fourier transform in which the orientation index and bundle packing of collagen were quantitatively analyzed. Some significant differences in collagen-related changes are found in different aging skins, which can be good indicators for the statuses of aging skins. The results are valuable to the study of aging skin and also of interest to biomedical photonics.

  14. Phase-shifting Zernike phase contrast microscopy for quantitative phase measurement.

    PubMed

    Gao, Peng; Yao, Baoli; Harder, Irina; Lindlein, Norbert; Torcal-Milla, Francisco Jose

    2011-11-01

    Zernike phase contrast microscopy is extended and combined with a phase-shifting mechanism to perform quantitative phase measurements of microscopic objects. Dozens of discrete point light sources on a ring are constructed for illumination. For each point light source, three different levels of point-like phase steps are designed, which are alternatively located along a ring on a silica plate to perform phase retardation on the undiffracted (dc) component of the object waves. These three levels of the phase steps are respectively selected by rotating the silica plate. Thus, quantitative evaluation of phase specimens can be performed via phase-shifting mechanism. The proposed method has low "halo" and "shade-off" effects, low coherent noise level, and high lateral resolution due to the improved illumination scheme. PMID:22048399

  15. Biomechanics of DNA structures visualized by 4D electron microscopy.

    PubMed

    Lorenz, Ulrich J; Zewail, Ahmed H

    2013-02-19

    We present a technique for in situ visualization of the biomechanics of DNA structural networks using 4D electron microscopy. Vibrational oscillations of the DNA structure are excited mechanically through a short burst of substrate vibrations triggered by a laser pulse. Subsequently, the motion is probed with electron pulses to observe the impulse response of the specimen in space and time. From the frequency and amplitude of the observed oscillations, we determine the normal modes and eigenfrequencies of the structures involved. Moreover, by selective "nano-cutting" at a given point in the network, it was possible to obtain Young's modulus, and hence the stiffness, of the DNA filament at that position. This experimental approach enables nanoscale mechanics studies of macromolecules and should find applications in other domains of biological networks such as origamis. PMID:23382239

  16. Combined Scanning Transmission Electron Microscopy Tilt- and Focal Series

    SciTech Connect

    Dahmen, Tim [German Research Center for Artificial Intelligence (DFKI), Germany] [German Research Center for Artificial Intelligence (DFKI), Germany; Baudoin, Jean-Pierre G [ORNL] [ORNL; Lupini, Andrew R [ORNL] [ORNL; Kubel, Christian [Karlsruhe Institute of Technology, Leopoldshafen, Germany] [Karlsruhe Institute of Technology, Leopoldshafen, Germany; Slusallek, Phillip [German Research Center for Artificial Intelligence (DFKI), Germany] [German Research Center for Artificial Intelligence (DFKI), Germany; De Jonge, Niels [ORNL] [ORNL

    2014-01-01

    In this study, a combined tilt- and focal series is proposed as a new recording scheme for high-angle annular dark-field scanning transmission electron microscopy (STEM) tomography. Three-dimensional (3D) data were acquired by mechanically tilting the specimen, and recording a through-focal series at each tilt direction. The sample was a whole-mount macrophage cell with embedded gold nanoparticles. The tilt focal algebraic reconstruction technique (TF-ART) is introduced as a new algorithm to reconstruct tomograms from such combined tilt- and focal series. The feasibility of TF-ART was demonstrated by 3D reconstruction of the experimental 3D data. The results were compared with a conventional STEM tilt series of a similar sample. The combined tilt- and focal series led to smaller missing wedge artifacts, and a higher axial resolution than obtained for the STEM tilt series, thus improving on one of the main issues of tilt series-based electron tomography.

  17. Cryogenic electron microscopy and single-particle analysis.

    PubMed

    Elmlund, Dominika; Elmlund, Hans

    2015-06-01

    About 20 years ago, the first three-dimensional (3D) reconstructions at subnanometer (<10-Å) resolution of an icosahedral virus assembly were obtained by cryogenic electron microscopy (cryo-EM) and single-particle analysis. Since then, thousands of structures have been determined to resolutions ranging from 30 Å to near atomic (<4 Å). Almost overnight, the recent development of direct electron detectors and the attendant improvement in analysis software have advanced the technology considerably. Near-atomic-resolution reconstructions can now be obtained, not only for megadalton macromolecular complexes or highly symmetrical assemblies but also for proteins of only a few hundred kilodaltons. We discuss the developments that led to this breakthrough in high-resolution structure determination by cryo-EM and point to challenges that lie ahead. PMID:25747402

  18. Four-dimensional ultrafast electron microscopy of phase transitions.

    PubMed

    Grinolds, Michael S; Lobastov, Vladimir A; Weissenrieder, Jonas; Zewail, Ahmed H

    2006-12-01

    Reported here is direct imaging (and diffraction) by using 4D ultrafast electron microscopy (UEM) with combined spatial and temporal resolutions. In the first phase of UEM, it was possible to obtain snapshot images by using timed, single-electron packets; each packet is free of space-charge effects. Here, we demonstrate the ability to obtain sequences of snapshots ("movies") with atomic-scale spatial resolution and ultrashort temporal resolution. Specifically, it is shown that ultrafast metal-insulator phase transitions can be studied with these achieved spatial and temporal resolutions. The diffraction (atomic scale) and images (nanometer scale) we obtained manifest the structural phase transition with its characteristic hysteresis, and the time scale involved (100 fs) is now studied by directly monitoring coordinates of the atoms themselves. PMID:17130445

  19. Detection and identification of light impurities by electron microscopy

    SciTech Connect

    Idrobo Tapia, Juan C [ORNL; Oxley, Mark P [ORNL; Walkosz, Weronika [University of Illinois, Chicago; Klie, Robert F [University of Illinois, Chicago; Ogut, Serdar [University of Illinois, Chicago; Mikijelj, B [Ceradyne Inc., Costa Mesa, CA; Pennycook, Stephen J [ORNL; Pantelides, Sokrates T. [Vanderbilt University

    2009-01-01

    For over 40 years impurities have been believed to stabilize the ceramic {alpha}-Si{sub 3}N{sub 4} but there is no direct evidence for their identity or lattice location. In bulk materials electron microscopy can generally image heavy impurities. Here we report direct imaging of N columns in {alpha}-Si{sub 3}N{sub 4} that suggests the presence of excess light elements in specific N columns. First-principles calculations rule out Si or N interstitials and suggest O impurities, which are then confirmed by atomically resolved electron-energy-loss spectroscopy. The result provides a possible explanation for the stability of {alpha}-Si{sub 3}N{sub 4} with implications for the design of next-generation structural ceramics.

  20. Quantitative electron tomography: the effect of the three-dimensional point spread function.

    PubMed

    Heidari, Hamed; Van den Broek, Wouter; Bals, Sara

    2013-12-01

    The intensity levels in a three-dimensional (3D) reconstruction, obtained by electron tomography, can be influenced by several experimental imperfections. Such artifacts will hamper a quantitative interpretation of the results. In this paper, we will correct for artificial intensity variations by determining the 3D point spread function (PSF) of a tomographic reconstruction based on high angle annular dark field scanning transmission electron microscopy. The large tails of the PSF cause an underestimation of the intensity of smaller particles, which in turn hampers an accurate radius estimate. Here, the error introduced by the PSF is quantified and corrected a posteriori. PMID:23872036

  1. Interactive Stereo Electron Microscopy Enhanced with Virtual Reality LBNL-48336December 17, 2001 1 Interactive Stereo Electron Microscopy Enhanced with Virtual Reality

    E-print Network

    Interactive Stereo Electron Microscopy Enhanced with Virtual Reality LBNL-48336December 17, 2001 1 Interactive Stereo Electron Microscopy Enhanced with Virtual Reality E. Wes Bethela, S. Jacob Bastackyb representations of two types of virtual measurement instruments, a `protractor' and a `caliper.' The measurements

  2. Collaborative Computational Project for Electron cryo-Microscopy

    SciTech Connect

    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.

  3. Frontiers of in situ electron microscopy

    SciTech Connect

    Zheng, Haimei [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Zhu, Yimei [Brookhaven National Lab. (BNL), Upton, NY (United States); Meng, Shirley Ying [Univ. of California-San Diego, San Diego, CA (United States)

    2015-01-01

    In situ transmission electron microscopy (TEM) has become an increasingly important tool for materials characterization. It provides key information on the structural dynamics of a material during transformations and the correlation between structure and properties of materials. With the recent advances in instrumentation, including aberration corrected optics, sample environment control, the sample stage, and fast and sensitive data acquisition, in situ TEM characterization has become more and more powerful. In this article, a brief review of the current status and future opportunities of in situ TEM is included. It also provides an introduction to the six articles covered by in this issue of MRS Bulletin explore the frontiers of in situ electron microscopy, including liquid and gas environmental TEM, dynamic four-dimensional TEM, nanomechanics, ferroelectric domain switching studied by in situ TEM, and state-of-the-art atomic imaging of light elements (i.e., carbon atoms) and individual defects.

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

    PubMed Central

    Goldsbury, Claire; Baxa, Ulrich; Simon, Martha N.; Steven, Alasdair C.; Engel, Andreas; Wall, Joseph S.; Aebi, Ueli; Müller, Shirley A.

    2010-01-01

    Amyloid fibrils are filamentous protein aggregates implicated in several common diseases like Alzheimer’s disease and type II diabetes. Similar structures are also the molecular principle of the infectious spongiform encephalopathies like 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). PMID:20868754

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

    PubMed

    Poulikakos, L D; Partl, M N

    2010-11-01

    Direct observations of porous asphalt concrete samples in their natural state using optical and electron microscopy techniques led to useful information regarding the microstructure of two mixes and indicated a relationship between microstructure and in situ performance. This paper presents evidence that suboptimal microstructure can lead to premature failure thus making a first step in defining well or suboptimal performing pavements with a bottom-up approach (microstructure). Laboratory and field compaction produce different samples in terms of the microstructure. Laboratory compaction using the gyratory method has produced more microcracks in mineral aggregates after the binder had cooled. Well-performing mixes used polymer-modified binders, had a more homogeneous void structure with fewer elongated voids and better interlocking of the aggregates. Furthermore, well-performing mixes showed better distribution of the mastic and better coverage of the aggregates with bitumen. Low vacuum scanning electron microscopy showed that styrene butadiene styrene polymer modification in binder exists in the form of discontinuous globules and not continuous networks. A reduction in the polymer phase was observed as a result of aging and in-service use. PMID:20946381

  6. LAUR-82-1433 Wohletz and Krinsley: Scanning Electron Microscopy... 1

    E-print Network

    Abstract The scanning electron microscope was used to study the surface textures of basaltic hydromagmatic#12;LAUR-82-1433 Wohletz and Krinsley: Scanning Electron Microscopy... 1 Scanning Electron. Introduction Scanning electron microscopy (SEM) plays an increasing role in geology as a tool for understanding

  7. Monoclinic superstructure in the orthorhombic Ce10W22O81 from transmission electron microscopy

    E-print Network

    Boyer, Edmond

    Monoclinic superstructure in the orthorhombic Ce10W22O81 from transmission electron microscopy Loïc - A monoclinic superstructure occurring in a Ce10W22O81 compound was identified by transmission electron by electron diffraction, precession and high resolution electron microscopy. The orthorhombic space group Pbnm

  8. Imaging three-dimensional tissue architectures by focused ion beam scanning electron microscopy

    Microsoft Academic Search

    Kenneth M Y P'ng; Robert D Young; Christian Pinali; Carlo Knupp; Andrew J Quantock; Andrew J Bushby

    2011-01-01

    In this protocol, we describe a 3D imaging technique known as 'volume electron microscopy' or 'focused ion beam scanning electron microscopy (FIB\\/SEM)' applied to biological tissues. A scanning electron microscope equipped with a focused gallium ion beam, used to sequentially mill away the sample surface, and a backscattered electron (BSE) detector, used to image the milled surfaces, generates a large

  9. Electron microscopy investigations of nanoparticles for cancer diagnostic applications

    NASA Astrophysics Data System (ADS)

    Koh, Ai Leen

    This dissertation concerns electron microscopy characterization of magnetic (MNP) and surface enhanced Raman scattering (SERS) nanoparticles for in-vitro cancer diagnostic applications. Electron microscopy is an essential characterization tool owing to its (sub) nanometer spatial resolution. Structural information about the nanoparticles can be obtained using transmission electron microscopy (TEM), which can in turn be correlated to their physical characteristics. The scanning electron microscope (SEM) has excellent depth of field and can be effectively utilized to obtain high resolution information about nanoparticles binding onto cell surfaces. Part One of this thesis focuses on MNPs for bio-sensing and detection applications. As a preliminary study, chemically-synthesized, commercially-available iron oxide nanoparticles were compared against their laboratory-synthesized counterparts to assess their suitability for this application. The motivation for this initial study came about due to the lack of published data on commercially available iron oxide nanoparticles. TEM studies show that the latter are "beads" composed of multiple iron oxide cores encapsulated by a polymer shell, with large standard deviations in core diameter. Laboratory-synthesized iron oxide nanoparticles, on the other hand, are single core particles with small variations in diameter and therefore are expected to be better candidates for the required application. A key limitation in iron oxide nanoparticles is their relatively weak magnetic signals. The development of high moment Synthetic Anti-Ferromagnetic (SAF) nanoparticles aims to overcome this issue. SAFs are a novel class of MNPs fabricated using nanoimprint lithography, direct deposition of multilayer structure and final suspension into liquid medium (water). TEM analyses of cross-section specimens reveal that the SAFs possess characteristics similar to those of sputtered magnetic multilayer thin films. Their layered structure is preserved after a chemical etch. Magnetic measurements show a slight decrease in magnetic moment after ion milling. From TEM characterization, the introduction of oxygen into the copper release layer, prior the film deposition process, can effectively control the topography of the oxidized-copper grains and, consequently, lead to the production of SAF nanoparticles with flatter layers. Size distribution studies performed on SAFs fabricated using self-assembled stamps show that it is possible to produce monodisperse nanoparticles with diameters from 70 nm up. Part Two of the dissertation describes structural characterization experiments performed on Composite Organic-Inorganic Nanoparticles (COINs), which are a novel type of SERS nanoclusters formed by aggregating silver nanoparticles with Raman molecules, and then encapsulating them with an organic coating that stabilizes the aggregates and promotes subsequent functionalization with antibodies. Part Three of this dissertation focuses on the development and application of electron microscopy-based techniques to characterize the nanomaterial-biology interactions, to assess how, or indeed whether, nanoparticles are attaching to the cancer cells. The technique of negative staining was applied to simultaneously visualize inorganic nanoparticles and their biofunctionalized entities under the TEM and to verify the successful functionalization of nanoparticles with antibodies. The interpretation of the negatively-stained COINs was consistent with the EFTEM data. Next, the localization and characterization of CD54-functionalized COINs on the apicolateral portions of U937 leukemia cell lines was determined using TEM, SEM and Scanning Auger Microscopy. The analyses show that CD54 antigens are localized at a specific region on U937 leukemia cell surfaces. SEM imaging and SER spectroscopy correlation studies of different antibody-conjugated COINs attached onto different cancer cell lines show a direct correlation between the number of COINs binding to cells and the corresponding SER intensity. Finally, TEM was used to l

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

    PubMed

    Carlson, David B; Evans, James E

    2011-01-01

    The coupling of cryo-light microscopy (cryo-LM) and cryo-electron microscopy (cryo-EM) poses a number of advantages for understanding cellular dynamics and ultrastructure. First, cells can be imaged in a near native environment for both techniques. Second, due to the vitrification process, samples are preserved by rapid physical immobilization rather than slow chemical fixation. Third, imaging the same sample with both cryo-LM and cryo-EM provides correlation of data from a single cell, rather than a comparison of "representative samples". While these benefits are well known from prior studies, the widespread use of correlative cryo-LM and cryo-EM remains limited due to the expense and complexity of buying or building a suitable cryogenic light microscopy stage. Here we demonstrate the assembly, and use of an inexpensive cryogenic stage that can be fabricated in any lab for less than $40 with parts found at local hardware and grocery stores. This cryo-LM stage is designed for use with reflected light microscopes that are fitted with long working distance air objectives. For correlative cryo-LM and cryo-EM studies, we adapt the use of carbon coated standard 3-mm cryo-EM grids as specimen supports. After adsorbing the sample to the grid, previously established protocols for vitrifying the sample and transferring/handling the grid are followed to permit multi-technique imaging. As a result, this setup allows any laboratory with a reflected light microscope to have access to direct correlative imaging of frozen hydrated samples. PMID:21673645

  11. Characterization of protein immobilization on nanoporous gold using atomic force microscopy and scanning electron microscopy.

    PubMed

    Tan, Yih Horng; Schallom, John R; Ganesh, N Vijaya; Fujikawa, Kohki; Demchenko, Alexei V; Stine, Keith J

    2011-08-01

    Nanoporous gold (NPG), made by dealloying low carat gold alloys, is a relatively new nanomaterial finding application in catalysis, sensing, and as a support for biomolecules. NPG has attracted considerable interest due to its open bicontinuous structure, high surface-to-volume ratio, tunable porosity, chemical stability and biocompatibility. NPG also has the attractive feature of being able to be modified by self-assembled monolayers. Here we use scanning electron microscopy (SEM) and atomic force microscopy (AFM) to characterize a highly efficient approach for protein immobilization on NPG using N-hydroxysuccinimide (NHS) ester functionalized self-assembled monolayers on NPG with pore sizes in the range of tens of nanometres. Comparison of coupling under static versus flow conditions suggests that BSA (Bovine Serum Albumin) and IgG (Immunoglobulin G) can only be immobilized onto the interior surfaces of free standing NPG monoliths with good coverage under flow conditions. AFM is used to examine protein coverage on both the exterior and interior of protein modified NPG. Access to the interior surface of NPG for AFM imaging is achieved using a special procedure for cleaving NPG. AFM is also used to examine BSA immobilized on rough gold surfaces as a comparative study. In principle, the general approach described should be applicable to many enzymes, proteins and protein complexes since both pore sizes and functional groups present on the NPG surfaces are controllable. PMID:21750834

  12. A study of hydrogenated carbon fibers by scanning electron microscopy and confocal laser scanning microscopy.

    PubMed

    de la Cal, Antonio Madroñero; Aguado-Serrano, Juan; Rojas-Cervantes, Maria Luisa; Adame, Elena V Rosa; Marron, Belen Sarmiento; Rosende, Africa Castro; Nevshupa, Roman

    2009-06-01

    The hydrogen absorption process is studied in carbonaceous fibers produced from a mixture of methane and hydrogen. The absorption of the hydrogen was examined in two types of fibers, in "as-grown" state and after a process of desorption during an annealing to 1.473 K under vacuum. Later to its production process, the fibers withstand an oxidation in air to 973 K. The fibers were examined by means of scanning electron microscopy (SEM) and confocal microscopy by reflection. Differences in the behavior during the oxidation were observed between the fibers in as-grown state and those subjected to a further annealing. It could be verified that the fibers were really constituted by two different phases. In one of the phases, the storage of the hydrogen absorbed took place, whereas in the other phase there was no alteration. The process of annealing prior to the absorption of the hydrogen has an appreciable effect on the desorption rate of the hydrogen. PMID:19208389

  13. Noise characteristics of the gas ionization cascade used in low vacuum scanning electron microscopy

    SciTech Connect

    Tileli, Vasiliki; Thiel, Bradley L. [College of Nanoscale Science and Engineering, University at Albany-SUNY, 257 Fuller Road, Albany, New York 12203 (United States); Knowles, W. Ralph; Toth, Milos [FEI Company, 5350 NE Dawson Creek Drive, Hillsboro, Oregon 97124 (United States)

    2009-07-01

    The noise characteristics of gas cascade amplified electron signals in low vacuum scanning electron microscopy (LVSEM) are described and analyzed. We derive expressions for each component contributing to the total noise culminating in a predictive, quantitative model that can be used for optimization of LVSEM operating parameters. Signal and noise behavior is characterized experimentally and used to validate the model. Under most operating conditions, the noise is dominated by the excess noise generated in the gas amplification cascade. At high gains, the excess noise increases proportionally with gain such that the signal-to-noise ratio is constant. The effects of several instrument operating parameters, including working distance, gas pressure, beam current, and detector bias, are condensed and presented in the form of a master curve.

  14. Clinical applications of scanning electron microscopy and X-ray microanalysis in dermatology

    SciTech Connect

    Forslind, B.

    1984-01-01

    Scanning electron microscopy is frequently applied to dermatological problems, as is evident from a review of the recent literature. In this paper, preparation methods and new techniques allowing experimental studies on the integumentary system are emphasized. Quantitative analysis in the electron microscope by use of energy-dispersive X-ray microanalysis (EDX) has become an important accessory technique. EDX can, for instance, be used to study problems involving physiological changes induced in skin by agents causing contact reactions. Recently, it has been shown that treatment with DNCB, chromate and nickel causes changes in elemental distribution in guinea-pig skin. In addition, elemental uptake in the integumentary system and in pathological inclusions in skin can be analyzed.

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

    NASA Astrophysics Data System (ADS)

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

    2007-08-01

    In paleomagnetic and environmental magnetic studies the magnetomineralogical identification is usually based on a set of rock magnetic parameters, complemented by crystallographic and chemical information retrieved from X-ray diffraction (XRD), (electron) microscopy or energy dispersive spectroscopy (EDS) of selected samples. While very useful, each of these supplementary techniques has its limitations when applied to natural sample material which are related to low particle concentrations (down to the ppm range in marine sediments) and very fine grain sizes (down to the nm scale). Therefore, meaningful application of such techniques depends on sample quality. Electron backscatter diffraction (EBSD) of individual grains in scanning electron microscopy (SEM) enables mineralogical identification of grains down to ~0.2 micrometer and is particularly powerful when combined with EDS. In this study, we show the merits of EBSD for rock magnetic investigations by analyzing titanomagnetites and hemoilmenites of various compositions and submicron lamella of titanomagnetite-hemoilmenite intergrowths. Such particles often occur in natural marine sediments where EDS often has a semi-quantitative character and compositionally similar intergrowths may be difficult to distinguish. With the mineralogical information provided by EBSD unambiguous identification of spinel-type and trigonal oxides is obtained. Optimal EBSD patterns are gathered from smooth, polished surfaces, but here we show that interpretable EBSD patterns can be obtained directly from the surface of unconsolidated, so called `non-embedded' particles from marine sediments. This information enhances the interpretative value of rock magnetic parameters.

  16. Scanning electrochemical microscopy at thermal sprayed anti-corrosion coatings: Effect of thermal spraying on heterogeneous electron transfer kinetics

    Microsoft Academic Search

    Lee Johnson; Akbar Niaz; Adrian Boatwright; K. T. Voisey; Darren A. Walsh

    2011-01-01

    The effect of thermal spraying on the electrochemical activity of an anti-corrosion superalloy was studied quantitatively using scanning electrochemical microscopy (SECM). The superalloy used was Inconel 625 (a Ni base superalloy) and thin coatings of the alloy were formed on mild steel using high velocity oxy-fuel (HVOF) thermal spraying. The kinetics of electron transfer (ET) across the Inconel 625 coating\\/electrolyte

  17. Coherence-controlled holographic microscopy for live-cell quantitative phase imaging

    NASA Astrophysics Data System (ADS)

    Slabý, TomáÅ.¡; K?ížová, Aneta; Lošt'ák, Martin; ?olláková, Jana; Jůzová, Veronika; Veselý, Pavel; Chmelík, Radim

    2015-03-01

    In this paper we present coherence-controlled holographic microscopy (CCHM) and various examples of observations of living cells including combination of CCHM with fluorescence microscopy. CCHM is a novel technique of quantitative phase imaging (QPI). It is based on grating off-axis interferometer, which is fully adapted for the use of incoherent illumination. This enables high-quality QPI free from speckles and parasitic interferences and lateral resolution of classical widefield microscopes. Label-free nature of QPI makes CCHM a useful tool for long-term observations of living cells. Moreover, coherence-gating effect induced by the use of incoherent illumination enables QPI of cells even in scattering media. Combination of CCHM with common imaging techniques brings the possibility to exploit advantages of QPI while simultaneously identifying the observed structures or processes by well-established imaging methods. We used CCHM for investigation of general parameters of cell life cycles and for research of cells reactions to different treatment. Cells were also visualized in 3D collagen gel with the use of CCHM. It was found that both the cell activity and movement of the collagen fibers can be registered. The method of CCHM in combination with fluorescence microscopy was used in order to obtain complementary information about cell morphology and identify typical morphological changes associated with different types of cell death. This combination of CCHM with common imaging technique has a potential to provide new knowledge about various processes and simultaneously their confirmation by comparison with known imaging method.

  18. FEATURE ARTICLE Transmission Electron Microscopy of Shape-Controlled Nanocrystals and Their Assemblies

    E-print Network

    Wang, Zhong L.

    FEATURE ARTICLE Transmission Electron Microscopy of Shape-Controlled Nanocrystals the fundamentals of TEM and its applications in structural determination of shape-controlled nanocrystals the chemical and electronic structure of individual nanocrystals. Electron energy-loss spectroscopy analysis

  19. Identification and quantitive analysis of calcium phosphate microparticles in intestinal tissue by nuclear microscopy

    NASA Astrophysics Data System (ADS)

    Gomez-Morilla, Inmaculada; Thoree, Vinay; Powell, Jonathan J.; Kirkby, Karen J.; Grime, Geoffrey W.

    2006-08-01

    Microscopic particles (0.5-2 ?m diameter), rich in calcium and phosphorus, are found in the lumen of the mid-distal gut of all mammals investigated, including humans, and these may play a role in immuno-surveillance and immune regulation of antigens from food and symbiotic bacteria that are contained in the gut. Whether these particles can cross in to tissue of the intestinal mucosa is unclear. If so, characterising their morphology and chemical composition is an important task in elucidating their function. The analysis of calcium phosphate in biological tissues has been approached in several ways including optical microscopy, scanning electron microscopy and, most recently in this work, with nuclear microscopy. In this paper, we describe the use of microPIXE and microRBS to locate these particles and to determine, accurately, the ratio of phosphorus to calcium using the information on sample thickness obtained from RBS to allow the PIXE ratios to be corrected. A commercial sample of hydroxy apatite was used to demonstrate accuracy and precision of the technique. Then, in a pilot study on intestinal tissue of mice, we demonstrated the presence of calcium phosphate microparticles, consistent with confocal microscopy observations, and we identified the average molar P:Ca molar ratio as 1.0. Further work will confirm the exact chemical speciation of these particles and will examine the influence of differing calcium containing diets on the formation of these microparticles.

  20. Quantitative neuroanatomy of all Purkinje cells with light sheet microscopy and high-throughput image analysis

    PubMed Central

    Silvestri, Ludovico; Paciscopi, Marco; Soda, Paolo; Biamonte, Filippo; Iannello, Giulio; Frasconi, Paolo; Pavone, Francesco S.

    2015-01-01

    Characterizing the cytoarchitecture of mammalian central nervous system on a brain-wide scale is becoming a compelling need in neuroscience. For example, realistic modeling of brain activity requires the definition of quantitative features of large neuronal populations in the whole brain. Quantitative anatomical maps will also be crucial to classify the cytoarchtitectonic abnormalities associated with neuronal pathologies in a high reproducible and reliable manner. In this paper, we apply recent advances in optical microscopy and image analysis to characterize the spatial distribution of Purkinje cells (PCs) across the whole cerebellum. Light sheet microscopy was used to image with micron-scale resolution a fixed and cleared cerebellum of an L7-GFP transgenic mouse, in which all PCs are fluorescently labeled. A fast and scalable algorithm for fully automated cell identification was applied on the image to extract the position of all the fluorescent PCs. This vectorized representation of the cell population allows a thorough characterization of the complex three-dimensional distribution of the neurons, highlighting the presence of gaps inside the lamellar organization of PCs, whose density is believed to play a significant role in autism spectrum disorders. Furthermore, clustering analysis of the localized somata permits dividing the whole cerebellum in groups of PCs with high spatial correlation, suggesting new possibilities of anatomical partition. The quantitative approach presented here can be extended to study the distribution of different types of cell in many brain regions and across the whole encephalon, providing a robust base for building realistic computational models of the brain, and for unbiased morphological tissue screening in presence of pathologies and/or drug treatments. PMID:26074783

  1. Quantitative neuroanatomy of all Purkinje cells with light sheet microscopy and high-throughput image analysis.

    PubMed

    Silvestri, Ludovico; Paciscopi, Marco; Soda, Paolo; Biamonte, Filippo; Iannello, Giulio; Frasconi, Paolo; Pavone, Francesco S

    2015-01-01

    Characterizing the cytoarchitecture of mammalian central nervous system on a brain-wide scale is becoming a compelling need in neuroscience. For example, realistic modeling of brain activity requires the definition of quantitative features of large neuronal populations in the whole brain. Quantitative anatomical maps will also be crucial to classify the cytoarchtitectonic abnormalities associated with neuronal pathologies in a high reproducible and reliable manner. In this paper, we apply recent advances in optical microscopy and image analysis to characterize the spatial distribution of Purkinje cells (PCs) across the whole cerebellum. Light sheet microscopy was used to image with micron-scale resolution a fixed and cleared cerebellum of an L7-GFP transgenic mouse, in which all PCs are fluorescently labeled. A fast and scalable algorithm for fully automated cell identification was applied on the image to extract the position of all the fluorescent PCs. This vectorized representation of the cell population allows a thorough characterization of the complex three-dimensional distribution of the neurons, highlighting the presence of gaps inside the lamellar organization of PCs, whose density is believed to play a significant role in autism spectrum disorders. Furthermore, clustering analysis of the localized somata permits dividing the whole cerebellum in groups of PCs with high spatial correlation, suggesting new possibilities of anatomical partition. The quantitative approach presented here can be extended to study the distribution of different types of cell in many brain regions and across the whole encephalon, providing a robust base for building realistic computational models of the brain, and for unbiased morphological tissue screening in presence of pathologies and/or drug treatments. PMID:26074783

  2. Comparison of transmission electron microscopy and optical microstructures in Al–1% Mg after plane strain compression

    Microsoft Academic Search

    G. J BAXTER; J. A. WHITEMAN; C. M SELLARS

    1997-01-01

    Modelling the microstructural evolution of aluminium alloys during hot rolling operations is becoming increasingly dependent\\u000a on accurate measurements of the deformed microstructure using transmission electron microscopy, scanning electron microscopy\\u000a and light microscopy. In this paper, an experimental technique which directly compares the microstructure observed in thin\\u000a foils with that observed using light microscopy is described.

  3. Three-dimensional scanning transmission electron microscopy of biological specimens

    SciTech Connect

    De Jonge, Niels [ORNL; Sougrat, Rachid [ORNL; Northan, Brian [Media Cybernetics, Inc.; Pennycook, Stephen J [ORNL

    2010-01-01

    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 data set. The precision of the height determination was 0.2 nm. The resolution of the reconstruction is comparable to that achieved by tilt-series transmission electron microscopy (TEM). 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 data set.

  4. Utility of Transmission Electron Microscopy in Small Round Cell Tumors

    PubMed Central

    Kim, Na Rae; Ha, Seung Yeon; Cho, Hyun Yee

    2015-01-01

    Small round cell tumors (SRCTs) are a heterogeneous group of neoplasms composed of small, primitive, and undifferentiated cells sharing similar histology under light microscopy. SRCTs include Ewing sarcoma/peripheral neuroectodermal tumor family tumors, neuroblastoma, desmoplastic SRCT, rhabdomyosarcoma, poorly differentiated round cell synovial sarcoma, mesenchymal chondrosarcoma, small cell osteosarcoma, small cell malignant peripheral nerve sheath tumor, and small cell schwannoma. Non-Hodgkin’s malignant lymphoma, myeloid sarcoma, malignant melanoma, and gastrointestinal stromal tumor may also present as SRCT. The current shift towards immunohistochemistry and cytogenetic molecular techniques for SRCT may be inappropriate because of antigenic overlapping or inconclusive molecular results due to the lack of differentiation of primitive cells and unavailable genetic service or limited moleculocytogenetic experience. Although usage has declined, electron microscopy (EM) remains very useful and shows salient features for the diagnosis of SRCTs. Although EM is not always required, it provides reliability and validity in the diagnosis of SRCT. Here, the ultrastructural characteristics of SRCTs are reviewed and we suggest that EM would be utilized as one of the reliable modalities for the diagnosis of undifferentiated and poorly differentiated SRCTs. PMID:25812730

  5. Correlating Intravital Multi-Photon Microscopy to 3D Electron Microscopy of Invading Tumor Cells Using Anatomical Reference Points

    PubMed Central

    Karreman, Matthia A.; Mercier, Luc; Schieber, Nicole L.; Shibue, Tsukasa; Schwab, Yannick; Goetz, Jacky G.

    2014-01-01

    Correlative microscopy combines the advantages of both light and electron microscopy to enable imaging of rare and transient events at high resolution. Performing correlative microscopy in complex and bulky samples such as an entire living organism is a time-consuming and error-prone task. Here, we investigate correlative methods that rely on the use of artificial and endogenous structural features of the sample as reference points for correlating intravital fluorescence microscopy and electron microscopy. To investigate tumor cell behavior in vivo with ultrastructural accuracy, a reliable approach is needed to retrieve single tumor cells imaged deep within the tissue. For this purpose, fluorescently labeled tumor cells were subcutaneously injected into a mouse ear and imaged using two-photon-excitation microscopy. Using near-infrared branding, the position of the imaged area within the sample was labeled at the skin level, allowing for its precise recollection. Following sample preparation for electron microscopy, concerted usage of the artificial branding and anatomical landmarks enables targeting and approaching the cells of interest while serial sectioning through the specimen. We describe here three procedures showing how three-dimensional (3D) mapping of structural features in the tissue can be exploited to accurately correlate between the two imaging modalities, without having to rely on the use of artificially introduced markers of the region of interest. The methods employed here facilitate the link between intravital and nanoscale imaging of invasive tumor cells, enabling correlating function to structure in the study of tumor invasion and metastasis. PMID:25479106

  6. Correlating intravital multi-photon microscopy to 3D electron microscopy of invading tumor cells using anatomical reference points.

    PubMed

    Karreman, Matthia A; Mercier, Luc; Schieber, Nicole L; Shibue, Tsukasa; Schwab, Yannick; Goetz, Jacky G

    2014-01-01

    Correlative microscopy combines the advantages of both light and electron microscopy to enable imaging of rare and transient events at high resolution. Performing correlative microscopy in complex and bulky samples such as an entire living organism is a time-consuming and error-prone task. Here, we investigate correlative methods that rely on the use of artificial and endogenous structural features of the sample as reference points for correlating intravital fluorescence microscopy and electron microscopy. To investigate tumor cell behavior in vivo with ultrastructural accuracy, a reliable approach is needed to retrieve single tumor cells imaged deep within the tissue. For this purpose, fluorescently labeled tumor cells were subcutaneously injected into a mouse ear and imaged using two-photon-excitation microscopy. Using near-infrared branding, the position of the imaged area within the sample was labeled at the skin level, allowing for its precise recollection. Following sample preparation for electron microscopy, concerted usage of the artificial branding and anatomical landmarks enables targeting and approaching the cells of interest while serial sectioning through the specimen. We describe here three procedures showing how three-dimensional (3D) mapping of structural features in the tissue can be exploited to accurately correlate between the two imaging modalities, without having to rely on the use of artificially introduced markers of the region of interest. The methods employed here facilitate the link between intravital and nanoscale imaging of invasive tumor cells, enabling correlating function to structure in the study of tumor invasion and metastasis. PMID:25479106

  7. Electronic environment for a field emission gun in electron microscopy H. Pinna, K. Liang (*), M. Denizart and B. Jouffrey

    E-print Network

    Paris-Sud XI, Université de

    659 Electronic environment for a field emission gun in electron microscopy H. Pinna, K. Liang of the source given by a field emis- sion gun is particularly interesting in electron microscopy. This paper ofthe numerous disruptive breakdowns which can occur in that type of gun. The fluctuations

  8. Watershed Merge Tree Classification for Electron Microscopy Image Segmentation

    SciTech Connect

    Liu, TIng; Jurrus, Elizabeth R.; Seyedhosseini, Mojtaba; Ellisman, Mark; Tasdizen, Tolga

    2012-11-11

    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 in the sense of optimization 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.

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

    NASA Astrophysics Data System (ADS)

    Buseck, Peter; Cowley, John; Eyring, Leroy

    1989-02-01

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

  10. Scanning electron microscopy in nematode-induced giant transfer cells.

    PubMed

    Jones, M G; Dropkin, V H

    1976-01-01

    A study of giant cells induced by the root-knot nematode, Meloidogyne incognita, in roots of Impatiens balsamina was made by scanning electron microscopy. The cytoplasmic contents of giant cells were removed by a procedure based on KOH digestion, to reveal inner wall structure. Wall ingrowths typical of transfer cells are present in giant cells from six days onwards after induction. They develop on walls adjacent to vascular tissues, and their distribution and development was examined. Pit fields contianing plasmodesmata become elaborated in walls between giant cells, but pit fields are lost between giant cells and cells outside them. The distribution of plasmodesmata in pit fields suggests that de novo formation of plasmodesmata occurs in walls between giant cells. Various aspects of giant cell formation and function are discussed and wall ingrowth development is compared in giant cells and normal transfer cells. PMID:1001022

  11. New Approach to Image Aerogels by Scanning Electron Microscopy

    NASA Astrophysics Data System (ADS)

    Solá, Francisco; Hurwitz, Frances; Yang, Jijing

    2011-03-01

    A new scanning electron microscopy (SEM) technique to image poor electrically conductive aerogels is presented. The process can be performed by non-expert SEM users. We showed that negative charging effects on aerogels can be minimized significantly by inserting dry nitrogen gas close to the region of interest. The process involves the local recombination of accumulated negative charges with positive ions generated from ionization processes. This new technique made possible the acquisition of images of aerogels with pores down to approximately 3nm in diameter using a positively biased Everhart-Thornley (E-T) detector. Well-founded concepts based on known models will also be presented with the aim to explain the results qualitatively.

  12. High Resolution Scanning Electron Microscopy of Cells Using Dielectrophoresis

    PubMed Central

    Tang, Shi-Yang; Zhang, Wei; Soffe, Rebecca; Nahavandi, Sofia; Shukla, Ravi; Khoshmanesh, Khashayar

    2014-01-01

    Ultrastructural analysis of cells can reveal valuable information about their morphological, physiological, and biochemical characteristics. Scanning electron microscopy (SEM) has been widely used to provide high-resolution images from the surface of biological samples. However, samples need to be dehydrated and coated with conductive materials for SEM imaging. Besides, immobilizing non-adherent cells during processing and analysis is challenging and requires complex fixation protocols. In this work, we developed a novel dielectrophoresis based microfluidic platform for interfacing non-adherent cells with high-resolution SEM at low vacuum mode. The system enables rapid immobilization and dehydration of samples without deposition of chemical residues over the cell surface. Moreover, it enables the on-chip chemical stimulation and fixation of immobilized cells with minimum dislodgement. These advantages were demonstrated for comparing the morphological changes of non-budding and budding yeast cells following Lyticase treatment. PMID:25089528

  13. Electron Microscopy Analysis of the Nucleolus of Trypanosoma cruzi

    NASA Astrophysics Data System (ADS)

    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.

  14. Imaging Magnetic Tunnel Junctions Using Ballistic Electron Emission Microscopy

    NASA Astrophysics Data System (ADS)

    Perrella, A. C.; Rippard, W. H.; Buhrman, R. A.

    2001-03-01

    The high spatial resolution and sensitive energy dependence of ballistic electron emission microscopy (BEEM) make it a powerful tool for studying metal oxide metal tunnel junction systems. We have used this technique to study both evaporated and sputtered cobalt aluminum oxide cobalt thin films whose tunnel magnetoresistance and high impedance make these systems relevant to magnetic random access memory development. The excellent spatial resolution of BEEM allows us to image defects in these junctions, specifically we can determine the density and electrical properties of weak points, commonly referred to as ‘pinholes’, in these barriers as a function of aluminum thickness and oxidation conditions. The energy dependent transport through these barriers has been investigated through BEEM spectroscopy. This allows us to determine the effective barrier height of the aluminum oxide as well as the identity of specific defects. These defects are generally one of two types, either conducting columns that extend through the barrier or exposed cobalt that was oxidized during fabrication.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

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

    PubMed

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

    2014-01-01

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

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

    PubMed Central

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

    2014-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-11-01

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

  19. Characterization of a peg-like terminal NOR structure with light microscopy and high-resolution scanning electron microscopy

    Microsoft Academic Search

    Elizabeth Schroeder-Reiter; Andreas Houben; Jürke Grau; Gerhard Wanner

    2006-01-01

    An atypical peg-like terminal constriction (“peg”) on metaphase chromosomes of the plant genus Oziroë could be identified as a nucleolus organizing region (NOR) by detecting 45S rDNA with correlative light microscopy (LM) and\\u000a scanning electron microscopy (SEM) in situ hybridization (ISH). Using high-resolution 3D analytical SEM, the architecture\\u000a and DNA distribution of the peg-like NOR were characterized as typical for

  20. Application of scanning electrochemical microscopy and scanning electron microscopy for the characterization of carbon-spray modified electrodes

    Microsoft Academic Search

    Gunther Wittstock; Hendrik Emons; Matthias Kummer; Jon R. Kirchhoff; William R. Heineman

    1994-01-01

    Different gold surfaces modified by carbon-spray have been investigated by scanning electron microscopy (SEM) and scanning electrochemical microscopy (SECM). A transformation of the SECM image to a distance-location profile is proposed which assists the correlation of both images. The structures found in the transformed SECM images of carbon-spray layers on gold substrates can be explained by the topographic features visible

  1. Quantitative microscopy and nanoscopy of sickle red blood cells performed by wide field digital interferometry

    NASA Astrophysics Data System (ADS)

    Shaked, Natan T.; Satterwhite, Lisa L.; Telen, Marilyn J.; Truskey, George A.; Wax, Adam

    2011-03-01

    We have applied wide-field digital interferometry (WFDI) to examine the morphology and dynamics of live red blood cells (RBCs) from individuals who suffer from sickle cell anemia (SCA), a genetic disorder that affects the structure and mechanical properties of RBCs. WFDI is a noncontact, label-free optical microscopy approach that can yield quantitative thickness profiles of RBCs and measurements of their membrane fluctuations at the nanometer scale reflecting their stiffness. We find that RBCs from individuals with SCA are significantly stiffer than those from a healthy control. Moreover, we show that the technique is sensitive enough to distinguish classes of RBCs in SCA, including sickle RBCs with apparently normal morphology, compared to the stiffer crescent-shaped sickle RBCs. We expect that this approach will be useful for diagnosis of SCA and for determining efficacy of therapeutic agents.

  2. Quantitative phase microscopy using defocusing by means of a spatial light modulator.

    PubMed

    Camacho, Luis; Micó, Vicente; Zalevsky, Zeev; García, Javier

    2010-03-29

    A new method for recovery the quantitative phase information of microscopic samples is presented. It is based on a spatial light modulator (SLM) and digital image processing as key elements to extract the sample's phase distribution. By displaying a set of lenses with different focal power, the SLM produces a set of defocused images of the input sample at the CCD plane. Such recorded images are then numerically processed to retrieve phase information. This iterative process is based on the wave propagation equation and leads on a complex amplitude image containing information of both amplitude and phase distributions of the input sample diffracted wave front. The proposed configuration is a non-interferometric architecture (conventional transmission imaging mode) where no moving elements are included. Experimental results perfectly correlate with the results obtained by conventional digital holographic microscopy (DHM). PMID:20389696

  3. Advanced scanning transmission electron microscopy characterization of UV LED nanowires

    NASA Astrophysics Data System (ADS)

    Phillips, Patrick; Kumar, Rajan; Carnevale, Santino; Myers, Roberto; Klie, Robert

    2013-03-01

    The role of aberration-corrected scanning transmission electron microscopy (STEM) in materials characterization is examined in regards to Al(x)Ga(1-x)N nanowires. Wires were graded from x =0 to x =1 and then from x =1 to x =0 with a small active quantum disk region located between the two gradations. This configuration is the basis for previously reported UV light emitting diodes. However, to assist subsequent growth processes while striving for optimum efficiency, both structural and chemical characterization methods are necessary, which can be provided at sufficiently high resolutions by advanced STEM instruments. Specifically, structural characterization will focus on determining layer thicknesses and wire polarity, as well as visualizing any short-range ordering and/or stacking faults that may be present. STEM multislice image simulations will also be discussed. Chemically, both energy dispersive X-ray (EDX) and electron energy loss (EEL) spectroscopies will be discussed in various capacities, ranging from quantum well composition (EDX) to N K-edge fine structure of both GaN and AlN (EELS).

  4. Photooxidation technology for correlative light and electron microscopy.

    PubMed

    Meisslitzer-Ruppitsch, Claudia; Röhrl, Clemens; Ranftler, Carmen; Stangl, Herbert; Neumüller, Josef; Pavelka, Margit; Ellinger, Adolf

    2013-01-01

    Correlative microscopic approaches combine the advantages of both light and electron microscopy. Here we show a correlative approach that uses the photooxidation capacity of fluorescent dyes. Through illumination with high energetic light, the chromogen diaminobenzidine is oxidized and stable deposits are formed at the sites of the former fluorescent signals, which after osmification are then visible in the electron microscope. The potential of the method is illustrated by tracing the endocytic pathway of three different ligands: the lipid ceramide, high density lipoproteins, and the lectin wheat germ agglutinin. The ligands were labeled either with BODIPY or Alexa dyes. Following cell surface binding, uptake, and time-dependent intracellular progression, the route taken by these molecules together with the organelles that have been visited is characterized. Correlative microscopic data are recorded at various levels. First, by fluorescence and phase contrast illumination with the light microscope, followed by the analysis of semithin sections after photooxidation, and finally of thin sections at the ultrastructural level. PMID:23027015

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

    SciTech Connect

    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.

  6. Electron microscopy analysis of mineral fibers in human lung tissue

    SciTech Connect

    Friedrichs, K.H.; Brockmann, M.; Fischer, M.; Wick, G. (Medical Institute of Environmental Hygiene, Heinrich Heine University, Duesseldorf (Germany))

    1992-01-01

    In the present study, lung samples from 126 autopsied cases were examined to determine the content of mineral fibers using analytical transmission electron microscopy (ATEM). The cases were divided into four groups (22 lungs of persons exposed to ambient environmental pollution, 32 cases of mesothelioma, 38 cases of primary lung cancer, and 34 asbestosis cases, 13 of these with additional pleural plaques). Fibers were counted, measured, and mineralogically identified using a combination of X-ray microanalysis and electron diffraction of the non-oriented fiber. Concentration of fibrous particles (defined as particles above 1 micron in length with roughly parallel long sides and an aspect ratio of 5:1 and greater) was calculated as fibers 10(6)/g dry lung weight. The concentration of chrysotile was found to be similar throughout the groups except for two cases in the asbestosis group with comparably high numbers of chrysotile. However, a remarkable difference for amphiboles could be observed between the groups. Asbestos bodies were mostly found in the asbestosis group. There was a rather good correlation between numbers of amphibole fibers and asbestos bodies, with an average ratio of 10:1. For comparison purposes between occupationally exposed/non-exposed individuals, a transition was found in the concentration range of 3-10(7) asbestos fibers/g dried lung weight.

  7. Electron Microscopy Characterization of Vanadium Dioxide Thin Films and Nanoparticles

    NASA Astrophysics Data System (ADS)

    Rivera, Felipe

    Vanadium dioxide (VO_2) is a material of particular interest due to its exhibited metal to insulator phase transition at 68°C that is accompanied by an abrupt and significant change in its electronic and optical properties. Since this material can exhibit a reversible drop in resistivity of up to five orders of magnitude and a reversible drop in infrared optical transmission of up to 80%, this material holds promise in several technological applications. Solid phase crystallization of VO_2 thin films was obtained by a post-deposition annealing process of a VO_{x,x approx 2} amorphous film sputtered on an amorphous silicon dioxide (SiO_2) layer. Scanning electron microscopy (SEM) and electron-backscattered diffraction (EBSD) were utilized to study the morphology of the solid phase crystallization that resulted from this post-deposition annealing process. The annealing parameters ranged in temperature from 300°C up to 1000°C and in time from 5 minutes up to 12 hours. Depending on the annealing parameters, EBSD showed that this process yielded polycrystalline vanadium dioxide thin films, semi-continuous thin films, and films of isolated single-crystal particles. In addition to these films on SiO_2, other VO_2 thin films were deposited onto a-, c-, and r-cuts of sapphire and on TiO_2(001) heated single-crystal substrates by pulsed-laser deposition (PLD). The temperature of the substrates was kept at ˜500°C during deposition. EBSD maps and orientation imaging microscopy were used to study the epitaxy and orientation of the VO_2 grains deposited on the single crystal substrates, as well as on the amorphous SiO_2 layer. The EBSD/OIM results showed that: 1) For all the sapphire substrates analyzed, there is a predominant family of crystallographic relationships wherein the rutile VO_2{001} planes tend to lie parallel to the sapphire's {10-10} and the rutile VO_2{100} planes lie parallel to the sapphire's {1-210} and {0001}. Furthermore, while this family of relationships accounts for the majority of the VO_2 grains observed, due to the sapphire substrate's geometry there were variations within these rules that changed the orientation of VO_2 grains with respect to the substrate's normal direction. 2) For the TiO_2, a substrate with a lower lattice mismatch, we observe the expected relationship where the rutile VO_2 [100], [110], and [001] crystal directions lie parallel to the TiO_2 substrate's [100], [110], and [001] crystal directions respectively. 3) For the amorphous SiO_2 layer, all VO_2 crystals that were measurable (those that grew to the thickness of the deposited film) had a preferred orientation with the the rutile VO_2[001] crystal direction tending to lie parallel to the plane of the specimen. The use of transmission electron microscopy (TEM) is presented as a tool for further characterization studies of this material and its applications. In this work TEM diffraction patterns taken from cross-sections of particles of the a- and r-cut sapphire substrates not only solidified the predominant family mentioned, but also helped lift the ambiguity present in the rutile VO_2{100} axes. Finally, a focused-ion beam technique for preparation of cross-sectional TEM samples of metallic thin films deposited on polymer substrates is demonstrated.

  8. Using advanced electron microscopy for the characterization of catalytic materials

    NASA Astrophysics Data System (ADS)

    Pyrz, William D.

    Catalysis will continue to be vitally important to the advancement and sustainability of industrialized societies. Unfortunately, the petroleum-based resources that currently fuel the energy and consumer product needs of an advancing society are becoming increasingly difficult and expensive to extract as supplies diminish and the quality of sources degrade. Therefore, the development of sustainable energy sources and the improvement of the carbon efficiency of existing chemical processes are critical. Further challenges require that these initiatives are accomplished in an environmentally friendly fashion since the effects of carbon-based emissions are proving to be a serious threat to global climate stability. In this dissertation, materials being developed for sustainable energy and process improvement initiatives are studied. Our approach is to use materials characterization, namely advanced electron microscopy, to analyze the targeted systems at the nano- or Angstrom-scale with the goal of developing useful relationships between structure, composition, crystalline order, morphology, and catalytic performance. One area of interest is the complex Mo-V-M-O (M=Te, Sb, Ta, Nb) oxide system currently being developed for the selective oxidation/ammoxidation of propane to acrylic acid or acrylonitrile, respectively. Currently, the production of acrylic acid and acrylonitrile rely on propylene-based processes, yet significant cost savings could be realized if the olefin-based feeds could be replaced by paraffin-based ones. The major challenge preventing this feedstock replacement is the development of a suitable paraffin-activating catalyst. Currently, the best candidate is the Mo-V-Nb-Te-O complex oxide catalyst that is composed of two majority phases that are commonly referred to as M1 and M2. However, there is a limited understanding of the roles of each component with respect to how they contribute to catalyst stability and the reaction mechanism. Aberration-corrected electron microscopy was used to systematically examine, atomic column by atomic column, the effect of elemental substitution on the long-range crystalline order, atomic coordinates, and site occupancies of the various formulations such that trends could be developed linking these properties to catalytic yields. To accomplish this task, an algorithm was developed that enabled the direct extraction of atomic coordinates and site occupancies from high-angle annular dark-field (HAADF) images to within 1% and 15% uncertainty, respectively. Furthermore, this general method could be applied to various crystalline systems and may dramatically improve the quality of initial structural models used in Rietveld refinements. Improvement in the quality of starting models may increase the structural and chemical complexity of inorganic structures that can be solved by using "powder methods" alone. In addition to the development of these trends, HAADF analyses also revealed the presence of coherent compositional miscibility gaps, rotational twin domains, and structural intergrowths in the complex Mo-V-M-O oxide system. Other catalytic systems that are addressed in this dissertation include Pd, Ag, and bimetallic Pd-Ag catalysts for the selective hydrogenation of acetylene in excess ethylene, alkali and alkaline earth promoted Ru catalysts for the production of clean hydrogen through the decomposition of ammonia, the production of Pt nanoparticles using dendrimer templates, and Pt-Re bimetallic catalysts for the conversion of glycerol to hydrocarbons and syn gas. In each of these studies, electron microscopy was used as a complimentary tool to synthetic and reaction studies to better understand interactions between the nanoparticles and the support/template, to determine the effect of adding various promoters, or to understand the nanoscale structural and chemical changes associated with the formation of bimetallic nanoparticles. A final area addressed in this dissertation is the interaction between the electron beam and the specimen. In one particular study direct

  9. Quantitative analysis of volume images -electron microscopic tomography of HIV

    E-print Network

    Nyström, Ingela

    Quantitative analysis of volume images - electron microscopic tomography of HIV Ingela Nystr to assist in the structural analysis of the causative virus of the AIDS disease, HIV. Especially interestingom, Ewert Bengtsson, Bo Nordin Centre for Image Analysis Uppsala University, Sweden Gunilla Borgefors Centre

  10. Transmission Electron Microscopy at Palaiseau Orsay Saclay: TEMPOS

    E-print Network

    moyenne gamme en microscopie électronique: FEG+cryo: HRTEM+Analyse SEM FEG + HADF FIB CHROMATEM (LPS + HADF FIB CHROMATEM (LPS gamme en microscopie électronique: FEG+cryo: HRTEM+Analyse SEM FEG + HADF FIB CHROMATEM (LPS

  11. Time-resolved fluorescence microscopy for quantitative Ca2+ imaging in living cells.

    PubMed

    Sagolla, Kristina; Löhmannsröben, Hans-Gerd; Hille, Carsten

    2013-10-01

    Calcium (Ca(2+)) is a ubiquitous intracellular second messenger and involved in a plethora of cellular processes. Thus, quantification of the intracellular Ca(2+) concentration ([Ca(2+)]i) and of its dynamics is required for a comprehensive understanding of physiological processes and potential dysfunctions. A powerful approach for studying [Ca(2+)]i is the use of fluorescent Ca(2+) indicators. In addition to the fluorescence intensity as a common recording parameter, the fluorescence lifetime imaging microscopy (FLIM) technique provides access to the fluorescence decay time of the indicator dye. The nanosecond lifetime is mostly independent of variations in dye concentration, allowing more reliable quantification of ion concentrations in biological preparations. In this study, the feasibility of the fluorescent Ca(2+) indicator Oregon Green Bapta-1 (OGB-1) for two-photon fluorescence lifetime imaging microscopy (2P-FLIM) was evaluated. In aqueous solution, OGB-1 displayed a Ca(2+)-dependent biexponential fluorescence decay behaviour, indicating the presence of a Ca(2+)-free and Ca(2+)-bound dye form. After sufficient dye loading into living cells, an in situ calibration procedure has also unravelled the Ca(2+)-free and Ca(2+)-bound dye forms from a global biexponential fluorescence decay analysis, although the dye's Ca(2+) sensitivity is reduced. Nevertheless, quantitative [Ca(2+)]i recordings and its stimulus-induced changes in salivary gland cells could be performed successfully. These results suggest that OGB-1 is suitable for 2P-FLIM measurements, which can gain access to cellular physiology. PMID:23975087

  12. Large-scale automatic reconstruction of neuronal processes from electron microscopy images.

    PubMed

    Kaynig, Verena; Vazquez-Reina, Amelio; Knowles-Barley, Seymour; Roberts, Mike; Jones, Thouis R; Kasthuri, Narayanan; Miller, Eric; Lichtman, Jeff; Pfister, Hanspeter

    2015-05-01

    Automated sample preparation and electron microscopy enables acquisition of very large image data sets. These technical advances are of special importance to the field of neuroanatomy, as 3D reconstructions of neuronal processes at the nm scale can provide new insight into the fine grained structure of the brain. Segmentation of large-scale electron microscopy data is the main bottleneck in the analysis of these data sets. In this paper we present a pipeline that provides state-of-the art reconstruction performance while scaling to data sets in the GB-TB range. First, we train a random forest classifier on interactive sparse user annotations. The classifier output is combined with an anisotropic smoothing prior in a Conditional Random Field framework to generate multiple segmentation hypotheses per image. These segmentations are then combined into geometrically consistent 3D objects by segmentation fusion. We provide qualitative and quantitative evaluation of the automatic segmentation and demonstrate large-scale 3D reconstructions of neuronal processes from a 27,000?m(3) volume of brain tissue over a cube of 30?m in each dimension corresponding to 1000 consecutive image sections. We also introduce Mojo, a proofreading tool including semi-automated correction of merge errors based on sparse user scribbles. PMID:25791436

  13. Quantitative analysis of intrinsic skin aging in dermal papillae by in vivo harmonic generation microscopy.

    PubMed

    Liao, Yi-Hua; Kuo, Wei-Cheng; Chou, Sin-Yo; Tsai, Cheng-Shiun; Lin, Guan-Liang; Tsai, Ming-Rung; Shih, Yuan-Ta; Lee, Gwo-Giun; Sun, Chi-Kuang

    2014-09-01

    Chronological skin aging is associated with flattening of the dermal-epidermal junction (DEJ), but to date no quantitative analysis focusing on the aging changes in the dermal papillae (DP) has been performed. The aim of the study is to determine the architectural changes and the collagen density related to chronological aging in the dermal papilla zone (DPZ) by in vivo harmonic generation microscopy (HGM) with a sub-femtoliter spatial resolution. We recruited 48 Asian subjects and obtained in vivo images on the sun-protected volar forearm. Six parameters were defined to quantify 3D morphological changes of the DPZ, which we analyzed both manually and computationally to study their correlation with age. The depth of DPZ, the average height of isolated DP, and the 3D interdigitation index decreased with age, while DP number density, DP volume, and the collagen density in DP remained constant over time. In vivo high-resolution HGM technology has uncovered chronological aging-related variations in DP, and sheds light on real-time quantitative skin fragility assessment and disease diagnostics based on collagen density and morphology. PMID:25401037

  14. Lab on chip optical imaging of biological sample by quantitative phase microscopy

    NASA Astrophysics Data System (ADS)

    Memmolo, P.; Miccio, L.; Merola, F.; Gennari, O.; Mugnano, M.; Netti, P. A.; Ferraro, P.

    2015-03-01

    Quantitative imaging and three dimensional (3D) morphometric analysis of flowing and not-adherent cells is an important aspect for diagnostic purposes at Lab on Chip scale. Diagnostics tools need to be quantitative, label-free and, as much as possible, accurate. In recent years digital holography (DH) has been improved to be considered as suitable diagnostic method in several research field. In this paper we demonstrate that DH can be used for retrieving 3D morphometric data for sorting and diagnosis aims. Several techniques exist for 3D morphological study as optical coherent tomography and confocal microscopy, but they are not the best choice in case of dynamic events as flowing samples. Recently, a DH approach, based on shape from silhouette algorithm (SFS), has been developed for 3D shape display and calculation of cells biovolume. Such approach, adopted in combination with holographic optical tweezers (HOT) was successfully applied to cells with convex shape. Unfortunately, it's limited to cells with convex surface as sperm cells or diatoms. Here, we demonstrate an improvement of such procedure. By decoupling thickness information from refractive index ones and combining this with SFS analysis, 3D shape of concave cells is obtained. Specifically, the topography contour map is computed and used to adjust the 3D shape retrieved by the SFS algorithm. We prove the new procedure for healthy red blood cells having a concave surface in their central region. Experimental results are compared with theoretical model.

  15. Quantitative comparison of preparation methodologies for X-ray fluorescence microscopy of brain tissue.

    PubMed

    James, Simon A; Myers, Damian E; de Jonge, Martin D; Vogt, Stefan; Ryan, Chris G; Sexton, Brett A; Hoobin, Pamela; Paterson, David; Howard, Daryl L; Mayo, Sheridan C; Altissimo, Matteo; Moorhead, Gareth F; Wilkins, Stephen W

    2011-08-01

    X-ray fluorescence microscopy (XFM) facilitates high-sensitivity quantitative imaging of trace metals at high spatial resolution over large sample areas and can be applied to a diverse range of biological samples. Accurate determination of elemental content from recorded spectra requires proper calibration of the XFM instrument under the relevant operating conditions. Here, we describe the manufacture, characterization, and utilization of multi-element thin-film reference foils for use in calibration of XFM measurements of biological and other specimens. We have used these internal standards to assess the two-dimensional distribution of trace metals in a thin tissue section of a rat hippocampus. The data used in this study was acquired at the XFM beamline of the Australian Synchrotron using a new 384-element array detector (Maia) and at beamline 2-ID-E at the Advanced Photon Source. Post-processing of samples by different fixation techniques was investigated, with the conclusion that differences in solvent type and sample handling can significantly alter elemental content. The present study highlights the quantitative capability, high statistical power, and versatility of the XFM technique for mapping trace metals in biological samples, e.g., brain tissue samples in order to help understand neurological processes, especially when implemented in conjunction with a high-performance detector such as Maia. PMID:21533642

  16. Quantitative analysis of intrinsic skin aging in dermal papillae by in vivo harmonic generation microscopy

    PubMed Central

    Liao, Yi-Hua; Kuo, Wei-Cheng; Chou, Sin-Yo; Tsai, Cheng-Shiun; Lin, Guan-Liang; Tsai, Ming-Rung; Shih, Yuan-Ta; Lee, Gwo-Giun; Sun, Chi-Kuang

    2014-01-01

    Chronological skin aging is associated with flattening of the dermal-epidermal junction (DEJ), but to date no quantitative analysis focusing on the aging changes in the dermal papillae (DP) has been performed. The aim of the study is to determine the architectural changes and the collagen density related to chronological aging in the dermal papilla zone (DPZ) by in vivo harmonic generation microscopy (HGM) with a sub-femtoliter spatial resolution. We recruited 48 Asian subjects and obtained in vivo images on the sun-protected volar forearm. Six parameters were defined to quantify 3D morphological changes of the DPZ, which we analyzed both manually and computationally to study their correlation with age. The depth of DPZ, the average height of isolated DP, and the 3D interdigitation index decreased with age, while DP number density, DP volume, and the collagen density in DP remained constant over time. In vivo high-resolution HGM technology has uncovered chronological aging-related variations in DP, and sheds light on real-time quantitative skin fragility assessment and disease diagnostics based on collagen density and morphology. PMID:25401037

  17. Quantitative Chemical Imaging and Unsupervised Analysis Using Hyperspectral Coherent Anti-Stokes Raman Scattering Microscopy

    PubMed Central

    2013-01-01

    In this work, we report a method to acquire and analyze hyperspectral coherent anti-Stokes Raman scattering (CARS) microscopy images of organic materials and biological samples resulting in an unbiased quantitative chemical analysis. The method employs singular value decomposition on the square root of the CARS intensity, providing an automatic determination of the components above noise, which are retained. Complex CARS susceptibility spectra, which are linear in the chemical composition, are retrieved from the CARS intensity spectra using the causality of the susceptibility by two methods, and their performance is evaluated by comparison with Raman spectra. We use non-negative matrix factorization applied to the imaginary part and the nonresonant real part of the susceptibility with an additional concentration constraint to obtain absolute susceptibility spectra of independently varying chemical components and their absolute concentration. We demonstrate the ability of the method to provide quantitative chemical analysis on known lipid mixtures. We then show the relevance of the method by imaging lipid-rich stem-cell-derived mouse adipocytes as well as differentiated embryonic stem cells with a low density of lipids. We retrieve and visualize the most significant chemical components with spectra given by water, lipid, and proteins segmenting the image into the cell surrounding, lipid droplets, cytosol, and the nucleus, and we reveal the chemical structure of the cells, with details visualized by the projection of the chemical contrast into a few relevant channels. PMID:24099603

  18. Detection of Secondary and Supersecondary Structures of Proteins from Cryo-Electron Microscopy

    PubMed Central

    Bajaj, Chandrajit; Goswami, Samrat; Zhang, Qin

    2012-01-01

    Recent advances in three-dimensional electron microscopy (3D EM) have enabled the quantitative visualization of the structural building blocks of proteins at improved resolutions. We provide algorithms to detect the secondary structures (?-helices and ?-sheets) from proteins for which the volumetric maps are reconstructed at 6–10Å resolution. Additionally, we show that when the resolution is coarser than 10Å, some of the super-secondary structures can be detected from 3D EM maps. For both these algorithms, we employ tools from computational geometry and differential topology, specifically the computation of stable/unstable manifolds of certain critical points of the distance function induced by the molecular surface. Our results connect mathematically well-defined constructions with bio-chemically induced structures observed in proteins. PMID:22186625

  19. Surface Kinetics of Copper Oxidation Investigated by In Situ Ultra-high Vacuum Transmission Electron Microscopy.

    PubMed

    Yang, Judith C.; Bharadwaj, Mridula D.; Zhou, Guangwen; Tropia, Lori

    2001-11-01

    We review our studies of the initial oxidation stages of Cu(001) thin films as investigated by in situ ultra-high vacuum transmission electron microscopy. We present our observations of surface reconstruction and the nucleation to coalescence of copper oxide during in situ oxidation in O2. We have proposed a semi-quantitative model, where oxygen surface diffusion is the dominant mechanism of the initial oxidation stages of Cu. We have also investigated the effect of water vapor on copper oxidation. We have observed that the presence of water vapor in the oxidizing atmosphere retards the rate of Cu oxidation and Cu2O is reduced when exposed directly to steam. PMID:12597793

  20. Avoiding drying-artifacts in transmission electron microscopy: Characterizing the size and colloidal state of nanoparticles

    PubMed Central

    Michen, Benjamin; Geers, Christoph; Vanhecke, Dimitri; Endes, Carola; Rothen-Rutishauser, Barbara; Balog, Sandor; Petri-Fink, Alke

    2015-01-01

    Standard transmission electron microscopy nanoparticle sample preparation generally requires the complete removal of the suspending liquid. Drying often introduces artifacts, which can obscure the state of the dispersion prior to drying and preclude automated image analysis typically used to obtain number-weighted particle size distribution. Here we present a straightforward protocol for prevention of the onset of drying artifacts, thereby allowing the preservation of in-situ colloidal features of nanoparticles during TEM sample preparation. This is achieved by adding a suitable macromolecular agent to the suspension. Both research- and economically-relevant particles with high polydispersity and/or shape anisotropy are easily characterized following our approach (http://bsa.bionanomaterials.ch), which allows for rapid and quantitative classification in terms of dimensionality and size: features that are major targets of European Union recommendations and legislation. PMID:25965905

  1. Mean atomic number quantitative assessment in backscattered electron imaging.

    PubMed

    Sánchez, E; Torres Deluigi, M; Castellano, G

    2012-12-01

    A method for obtaining quantitative mean atomic number images in a scanning electron microscope for different kinds of samples has been developed. The backscattered electron signal is monotonically increasing with the mean atomic number Z, and accordingly Z can be given as a function of the image gray levels. From results obtained from Monte Carlo simulations, an exponential function is fitted to convert the backscattered registered gray levels into a Z image map. Once this fitting was performed, the reproducibility of the Z determination was checked through the acquisition of backscattered electron images from metal and mineral standards. The developed method can be applied to any unknown sample, always controlling the experimental conditions, as shown here for a thin section of a rock in which several unknown mineral phases are present; the results obtained herein are compared to quantitative assessments performed with X-ray spectra from each mineral phase. PMID:23164359

  2. Quantitation of Glucocorticoid Receptor DNA-Binding Dynamics by Single-Molecule Microscopy and FRAP

    PubMed Central

    Groeneweg, Femke L.; van Royen, Martin E.; Fenz, Susanne; Keizer, Veer I. P.; Geverts, Bart; Prins, Jurrien; de Kloet, E. Ron; Houtsmuller, Adriaan B.; Schmidt, Thomas S.; Schaaf, Marcel J. M.

    2014-01-01

    Recent advances in live cell imaging have provided a wealth of data on the dynamics of transcription factors. However, a consistent quantitative description of these dynamics, explaining how transcription factors find their target sequences in the vast amount of DNA inside the nucleus, is still lacking. In the present study, we have combined two quantitative imaging methods, single-molecule microscopy and fluorescence recovery after photobleaching, to determine the mobility pattern of the glucocorticoid receptor (GR) and the mineralocorticoid receptor (MR), two ligand-activated transcription factors. For dexamethasone-activated GR, both techniques showed that approximately half of the population is freely diffusing, while the remaining population is bound to DNA. Of this DNA-bound population about half the GRs appeared to be bound for short periods of time (?0.7 s) and the other half for longer time periods (?2.3 s). A similar pattern of mobility was seen for the MR activated by aldosterone. Inactive receptors (mutant or antagonist-bound receptors) show a decreased DNA binding frequency and duration, but also a higher mobility for the diffusing population. Likely, very brief (?1 ms) interactions with DNA induced by the agonists underlie this difference in diffusion behavior. Surprisingly, different agonists also induce different mobilities of both receptors, presumably due to differences in ligand-induced conformational changes and receptor complex formation. In summary, our data provide a consistent quantitative model of the dynamics of GR and MR, indicating three types of interactions with DNA, which fit into a model in which frequent low-affinity DNA binding facilitates the search for high-affinity target sequences. PMID:24632838

  3. Dual-modality wide-field photothermal quantitative phase microscopy and depletion of cell populations

    NASA Astrophysics Data System (ADS)

    Turko, Nir A.; Barnea, Itay; Blum, Omry; Korenstein, Rafi; Shaked, Natan T.

    2015-03-01

    We review our dual-modality technique for quantitative imaging and selective depletion of populations of cells based on wide-field photothermal (PT) quantitative phase imaging and simultaneous PT cell extermination. The cells are first labeled by plasmonic gold nanoparticles, which evoke local plasmonic resonance when illuminated by light in a wavelength corresponding to their specific plasmonic resonance peak. This reaction creates changes of temperature, resulting in changes of phase. This phase changes are recorded by a quantitative phase microscope (QPM), producing specific imaging contrast, and enabling bio-labeling in phase microscopy. Using this technique, we have shown discrimination of EGFR over-expressing (EGFR+) cancer cells from EGFR under-expressing (EGFR-) cancer cells. Then, we have increased the excitation power in order to evoke greater temperatures, which caused specific cell death, all under real-time phase acquisition using QPM. Close to 100% of all EGFR+ cells were immediately exterminated when illuminated with the strong excitation beam, while all EGFR- cells survived. For the second experiment, in order to simulate a condition where circulating tumor cells (CTCs) are present in blood, we have mixed the EGFR+ cancer cells with white blood cells (WBCs) from a healthy donor. Here too, we have used QPM to observe and record the phase of the cells as they were excited for selective visualization and then exterminated. The WBCs survival rate was over 95%, while the EGFR+ survival rate was under 5%. The technique may be the basis for real-time detection and controlled treatment of CTCs.

  4. Cryo-Electron Microscopy Structure of Lactococcal Siphophage 1358 Virion

    PubMed Central

    Spinelli, Silvia; Bebeacua, Cecilia; Orlov, Igor; Tremblay, Denise; Klaholz, Bruno P.

    2014-01-01

    ABSTRACT Lactococcus lactis, a Gram+ lactic acid-producing bacterium used for the manufacture of several fermented dairy products, is subject to infection by diverse virulent tailed phages, leading to industrial fermentation failures. This constant viral risk has led to a sustained interest in the study of their biology, diversity, and evolution. Lactococcal phages now constitute a wide ensemble of at least 10 distinct genotypes within the Caudovirales order, many of them belonging to the Siphoviridae family. Lactococcal siphophage 1358, currently the only member of its group, displays a noticeably high genomic similarity to some Listeria phages as well as a host range limited to a few L. lactis strains. These genomic and functional characteristics stimulated our interest in this phage. Here, we report the cryo-electron microscopy structure of the complete 1358 virion. Phage 1358 exhibits noteworthy features, such as a capsid with dextro handedness and protruding decorations on its capsid and tail. Observations of the baseplate of virion particles revealed at least two conformations, a closed and an open, activated form. Functional assays uncovered that the adsorption of phage 1358 to its host is Ca2+ independent, but this cation is necessary to complete its lytic cycle. Taken together, our results provide the complete structural picture of a unique lactococcal phage and expand our knowledge on the complex baseplate of phages of the Siphoviridae family. IMPORTANCE Phages of Lactococcus lactis are investigated mainly because they are sources of milk fermentation failures in the dairy industry. Despite the availability of several antiphage measures, new phages keep emerging in this ecosystem. In this study, we provide the cryo-electron microscopy reconstruction of a unique lactococcal phage that possesses genomic similarity to particular Listeria phages and has a host range restricted to only a minority of L. lactis strains. The capsid of phage 1358 displays the almost unique characteristic of being dextro handed. Its capsid and tail exhibit decorations that we assigned to nonspecific sugar binding modules. We observed the baseplate of 1358 in two conformations, a closed and an open form. We also found that the adsorption to its host, but not infection, is Ca2+ independent. Overall, this study advances our understanding of the adhesion mechanisms of siphophages. PMID:24872584

  5. The Probe Profile and Lateral Resolution of Scanning Transmission Electron Microscopy of Thick Specimens

    PubMed Central

    Demers, Hendrix; Ramachandra, Ranjan; Drouin, Dominique; de Jonge, Niels

    2012-01-01

    Lateral profiles of the electron probe of scanning transmission electron microscopy (STEM) were simulated at different vertical positions in a micrometers-thick carbon sample. The simulations were carried out using the Monte Carlo method in the CASINO software. A model was developed to fit the probe profiles. The model consisted of the sum of a Gaussian function describing the central peak of the profile, and two exponential decay functions describing the tail of the profile. Calculations were performed to investigate the fraction of unscattered electrons as function of the vertical position of the probe in the sample. Line scans were also simulated over gold nanoparticles at the bottom of a carbon film to calculate the achievable resolution as function of the sample thickness and the number of electrons. The resolution was shown to be noise limited for film thicknesses less than 1 ?m. Probe broadening limited the resolution for thicker films. The validity of the simulation method was verified by comparing simulated data with experimental data. The simulation method can be used as quantitative method to predict STEM performance or to interpret STEM images of thick specimens. PMID:22564444

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

    SciTech Connect

    Dietz, N. L.

    2005-04-15

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

  7. Electron microscopy of iron chalcogenide FeTe(Se) films

    NASA Astrophysics Data System (ADS)

    Shchichko, I. O.; Presnyakov, M. Yu.; Stepantsov, E. A.; Kazakov, S. M.; Antipov, E. V.; Makarova, I. P.; Vasil'ev, A. L.

    2015-05-01

    The structure of Fe1 + ?Te1 - x Se x films ( x = 0; 0.05) grown on single-crystal MgO and LaAlO3 substrates has been investigated by transmission and scanning transmission electron microscopy. The study of Fe1.11Te/MgO structures has revealed two crystallographic orientation relationships between the film and substrate. It is shown that the lattice mismatch between the film and substrate is compensated for by the formation of misfit dislocations. The Burgers vector projection is determined. The stresses in the film can partially be compensated for due to the formation of an intermediate disordered layer. It is shown that a FeTe0.5Se0.5 film grown on a LaAlO3 substrate is single-crystal and that the FeTe0.5Se0.5/LaAlO3 interface in a selected region is coherent. The orientation relationships between the film and substrate are also determined for this case.

  8. Analytical electron microscopy of biogenic and inorganic carbonates

    NASA Technical Reports Server (NTRS)

    Blake, David F.

    1989-01-01

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

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

    SciTech Connect

    Hsieh, Kuang-Chien

    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.

  10. High-performance probes for light and electron microscopy.

    PubMed

    Viswanathan, Sarada; Williams, Megan E; Bloss, Erik B; Stasevich, Timothy J; Speer, Colenso M; Nern, Aljoscha; Pfeiffer, Barret D; Hooks, Bryan M; Li, Wei-Ping; English, Brian P; Tian, Teresa; Henry, Gilbert L; Macklin, John J; Patel, Ronak; Gerfen, Charles R; Zhuang, Xiaowei; Wang, Yalin; Rubin, Gerald M; Looger, Loren L

    2015-06-01

    We describe an engineered family of highly antigenic molecules based on GFP-like fluorescent proteins. These molecules contain numerous copies of peptide epitopes and simultaneously bind IgG antibodies at each location. These 'spaghetti monster' fluorescent proteins (smFPs) distributed well in neurons, notably into small dendrites, spines and axons. smFP immunolabeling localized weakly expressed proteins not well resolved with traditional epitope tags. By varying epitope and scaffold, we generated a diverse family of mutually orthogonal antigens. In cultured neurons and mouse and fly brains, smFP probes allowed robust, orthogonal multicolor visualization of proteins, cell populations and neuropil. smFP variants complement existing tracers and greatly increase the number of simultaneous imaging channels, and they performed well in advanced preparations such as array tomography, super-resolution fluorescence imaging and electron microscopy. In living cells, the probes improved single-molecule image tracking and increased yield for RNA-seq. These probes facilitate new experiments in connectomics, transcriptomics and protein localization. PMID:25915120

  11. Hybrid Electron Microscopy Normal Mode Analysis graphical interface and protocol.

    PubMed

    Sorzano, Carlos Oscar S; de la Rosa-Trevín, José Miguel; Tama, Florence; Joni?, Slavica

    2014-11-01

    This article presents an integral graphical interface to the Hybrid Electron Microscopy Normal Mode Analysis (HEMNMA) approach that was developed for capturing continuous motions of large macromolecular complexes from single-particle EM images. HEMNMA was shown to be a good approach to analyze multiple conformations of a macromolecular complex but it could not be widely used in the EM field due to a lack of an integral interface. In particular, its use required switching among different software sources as well as selecting modes for image analysis was difficult without the graphical interface. The graphical interface was thus developed to simplify the practical use of HEMNMA. It is implemented in the open-source software package Xmipp 3.1 (http://xmipp.cnb.csic.es) and only a small part of it relies on MATLAB that is accessible through the main interface. Such integration provides the user with an easy way to perform the analysis of macromolecular dynamics and forms a direct connection to the single-particle reconstruction process. A step-by-step HEMNMA protocol with the graphical interface is given in full details in Supplementary material. The graphical interface will be useful to experimentalists who are interested in studies of continuous conformational changes of macromolecular complexes beyond the modeling of continuous heterogeneity in single particle reconstruction. PMID:25268657

  12. Life Cycle of Neurospora crassa Viewed by Scanning Electron Microscopy

    PubMed Central

    Seale, Thomas

    1973-01-01

    Scanning electron microscopy was used to examine the major stages of the life cycle of two wild-type strains of Neurospora crassa Shear and Dodge (St. Lawrence 3.1a and 74A): mycelia, protoperithecium formation, perithecia, ascospores, ascospore germination and outgrowth, macro and microconidia, and germination and outgrowth of macroconidia. Structures seen at the limit of resolution of bright-field and phase-contrast microscopes, e.g., the ribbed surface of ascospores, are well resolved. New details of conidial development and surface structure are revealed. There appears to be only one distinguishable morphological difference between the two strains. The pattern of germination and outgrowth which seems relatively constant for strain 74A or strain 3.1a, appears to be different for each. Conidia from strain 3.1a almost always germinate from a site between interconidial attachment points; whereas the germ tubes of strain 74A usually emerge from or very near the interconidial attachment site. These germination patterns usually do not segregate 2:2 in asci dissected in order. This observation suggests that conidial germination pattern is not under the control of a single gene. Images PMID:4266170

  13. Histological preparation of developing vestibular otoconia for scanning electron microscopy

    NASA Technical Reports Server (NTRS)

    Huss, D.; Dickman, J. D.

    2003-01-01

    The unique nature of vestibular otoconia as calcium carbonate biominerals makes them particularly susceptible to chemical deformation during histological processing. We fixed and stored otoconia from all three otolith endorgans of embryonic, hatchling and adult Japanese quail in glutaraldehyde containing either phosphate or non-phosphate buffers for varying lengths of time and processed them for scanning electron microscopy. Otoconia from all age groups and otolith endorgans processed in 0.1 M phosphate buffer (pH 7.4) showed abnormal surface morphology when compared to acetone fixed controls. Otoconia processed in 0.1 M sodium cacodylate or HEPES buffered artificial endolymph (pH 7.4) showed normal morphology that was similar to controls. The degree of otoconial deformation was directly related to the time exposed to phosphate buffer. Short duration exposure produced particulate deformations while longer exposures resulted in fused otoconia that formed solid sheets. Otoconial surface deformation and fusing was independent of the glutaraldehyde component of the histological processing. These findings should help vestibular researchers to develop appropriate histological processing protocols in future studies of otoconia.

  14. Surface treatment of feldspathic porcelain: scanning electron microscopy analysis

    PubMed Central

    Valian, Azam

    2014-01-01

    PURPOSE Topographic analysis of treated ceramics provides qualitative information regarding the surface texture affecting the micromechanical retention and locking of resin-ceramics. This study aims to compare the surface microstructure following different surface treatments of feldspathic porcelain. MATERIALS AND METHODS This in-vitro study was conducted on 72 porcelain discs randomly divided into 12 groups (n=6). In 9 groups, feldspathic surfaces were subjected to sandblasting at 2, 3 or 4 bar pressure for 5, 10 or 15 seconds with 50 µm alumina particles at a 5 mm distance. In group 10, 9.5% hydrofluoric acid (HF) gel was applied for 120 seconds. In group 11, specimens were sandblasted at 3 bar pressure for 10 seconds and then conditioned with HF. In group 12, specimens were first treated with HF and then sandblasted at 3 bar pressure for 10 seconds. All specimens were then evaluated under scanning electron microscopy (SEM) at different magnifications. RESULTS SEM images of HF treated specimens revealed deep porosities of variable sizes; whereas, the sandblasted surfaces were more homogenous and had sharper peaks. Increasing the pressure and duration of sandblasting increased the surface roughness. SEM images of the two combined techniques showed that in group 11 (sandblasted first), HF caused deeper porosities; whereas in group 12 (treated with HF first) sandblasting caused irregularities with less homogeneity. CONCLUSION All surface treatments increased the surface area and caused porous surfaces. In groups subjected to HF, the porosities were deeper than those in sandblasted only groups. PMID:25352961

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

    PubMed Central

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

    2014-01-01

    Background Limbal ring (also known as ‘circle’) contact lenses are becoming increasingly popular, especially in Asian markets because of their eye-enhancing effects. The pigment particles that give the eye-enhancing effects of these lenses can be found on the front or back surface of the contact lens or ‘enclosed’ within the lens matrix. The purpose of this research was to evaluate the pigment location and surface roughness of seven types of ‘circle’ contact lenses. Methods Scanning electron microscopic (SEM) analysis was performed using a variable pressure Hitachi S3400N instrument to discern the placement of lens pigments. Atomic force microscopy (Dimension Icon AFM from Bruker Nano) was used to determine the surface roughness of the pigmented regions of the contact lenses. Atomic force microscopic analysis was performed in fluid phase under contact mode using a Sharp Nitride Lever probe (SNL-10) with a spring constant of 0.06 N/m. Root mean square (RMS) roughness values were analysed using a generalised linear mixed model with a log-normal distribution. Least square means and their corresponding 95% confidence intervals were estimated for each brand, location and pigment combination. Results SEM cross-sectional images at 500× and 2,000× magnification showed pigment on the surface of six of the seven lens types tested. The mean depth of pigment for 1-DAY ACUVUE DEFINE (1DAD) lenses was 8.1??m below the surface of the lens, while the remaining lens types tested had pigment particles on the front or back surface. Results of the atomic force microscopic analysis indicated that 1DAD lenses had significantly lower root mean square roughness values in the pigmented area of the lens than the other lens types tested. Conclusions SEM and AFM analysis revealed pigment on the surface of the lens for all types tested with the exception of 1DAD. Further research is required to determine if the difference in pigment location influences on-eye performance. PMID:24689948

  16. Using correlative light and electron microscopy to study zebrafish vascular morphogenesis.

    PubMed

    Goetz, Jacky G; Monduc, Fabien; Schwab, Yannick; Vermot, Julien

    2015-01-01

    Live imaging is extremely useful to characterize the dynamics of cellular events in vivo, yet it is limited in terms of spatial resolution. Correlative light and electron microscopy (CLEM) allows combining live confocal microscopy with electron microscopy (EM) for the characterization of biological samples at high temporal and spatial resolution. Here we describe a protocol allowing extracting endothelial cell ultrastructure after having imaged the same cell in its in vivo context through live confocal imaging during zebrafish embryonic development. PMID:25245685

  17. Verifying copper toxicosis in Bedlington terriers by analytical electron microscopy of needle biopsies of liver.

    PubMed

    Eriksson, J; Peura, R

    1989-05-01

    Diagnosis of copper toxicosis in Bedlington terriers was performed by analytical electron microscopy of needle biopsy of the liver. The animals were four Bedlington terriers clinically suspected of hereditary copper toxicosis, and four healthy control animals of the same breed. Light microscopy of the livers of the diseased animals revealed dense bodies in the hepatocytes which stained histochemically for copper. Analytical electron microscopy showed that the intrahepatocytic bodies consisted almost entirely of copper. PMID:2547852

  18. Low-voltage, high-resolution scanning electron microscopy: a new characterization technique for polymer morphology

    Microsoft Academic Search

    W. Wade Adams

    1995-01-01

    Low-voltage, high-resolution scanning electron microscopy (LVHRSEM) is a promising new technique for polymer morphological characterization, and provides complementary data to transmission electron microscopy, X-ray scattering and the scanning probe microscopies. Practically, lateral resolution on the order of 50 Å at 1.0 keV accelerating voltage can be obtained in polymer samples. The utility of LVHRSEM is demonstrated for diverse polymer systems,

  19. Use of scanning electron microscopy for the evaluation of intestinal epithelium integrity

    Microsoft Academic Search

    Marcio Heber Gomide Junior; Elton Vinícius Sterzo; Marcos Macari; Isabel Cristina Boleli

    2004-01-01

    This work reports the use of scanning electron microscopy to evaluate intestinal epithelium loss in broilers. Intestinal mucosa of male and female chicks submitted to prolonged period post-hatching of water and feed deprivation was evaluated. Two segments of the duodenum, jejunum and ileum were taken per bird, and routinely processed by scanning electron microscopy. Six distinct degrees of epithelium loss

  20. Chondrule thermal history from unequilibrated H chondrites: A transmission and analytical electron microscopy study

    Microsoft Academic Search

    C. Ferraris; L. Folco; M. Mellini

    2002-01-01

    Sixteen texturally different (porphyritic, barred, radial, cryptocrystalline) FeO-rich chondrules from the unequilibrated ordinary chondrites Brownfield, Frontier Mountain (FRO) 90003 and FRO 90032 were characterized by optical and scanning electron microscopy and then thoroughly studied by transmission and analytical electron microscopy. Nanotextural and nanochemical data indicate similar thermal evolution for chondrules of the same textural groups; minor, yet meaningful differences occur

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

    PubMed

    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. PMID:24275379

  2. A Transmission Electron Microscopy Study of Presolar Hibonite

    NASA Astrophysics Data System (ADS)

    Zega, Thomas J.; Alexander, Conel M. O'D.; Nittler, Larry R.; Stroud, Rhonda M.

    2011-04-01

    We report isotopic and microstructural data on five presolar hibonite grains (KH1, KH2, KH6, KH15, and KH21) identified in an acid residue of the Krymka LL3.1 ordinary chondrite. Isotopic measurements by secondary ion mass spectrometry (SIMS) verified a presolar circumstellar origin for the grains. Transmission electron microscopy (TEM) examination of the crystal structure and chemistry of the grains was enabled by in situ sectioning and lift-out with a focused-ion-beam scanning-electron microscope (FIB-SEM). Comparisons of isotopic compositions with models indicate that four of the five grains formed in low-mass stars that evolved through the red giant/asymptotic giant branches (RGBs/AGBs), whereas one grain formed in the ejecta of a Type II supernova. Selected-area electron-diffraction patterns show that all grains are single crystals of hibonite. Some grains contain minor structural perturbations (stacking faults) and small spreads in orientation that can be attributed to a combination of growth defects and mechanical processing by grain-grain collisions. The similar structure of the supernova grain to those from RGB/AGB stars indicates a similarity in the formation conditions. Radiation damage (e.g., point defects), if present, occurs below our detection limit. Of the five grains we studied, only one has the pure hibonite composition of CaAl12O19. All others contain minor amounts of Mg, Si, Ti, and Fe. The microstructural data are generally consistent with theoretical predictions, which constrain the circumstellar condensation temperature to a range of 1480-1743 K, assuming a corresponding total gas pressure between 1 × 10-6 and 1 × 10-3 atm. The TEM data were also used to develop a calibration for SIMS determination of Ti contents in oxide grains. Grains with extreme 18O depletions, indicating deep mixing has occurred in their parent AGB stars, are slightly Ti enriched compared with grains from stars without deep mixing, most likely reflecting differences in grain condensation conditions.

  3. Scanning transmission electron microscopy of novel gate stacks

    NASA Astrophysics Data System (ADS)

    Agustin, Melody Pacifico

    Continued scaling of Si-based complementary metal-oxide-semiconductor (CMOS) device has led to the decrease of the gate dielectric (SiO2) thickness. For SiO2 thinner than ˜8 Angstroms, direct electron tunneling results in excessive gate leakage. One attempt to resolve this issue has been the use of an alternate gate dielectric, one with a higher permittivity to allow for a greater physical thickness. HfO2 has been the focus of much research because it has a high permittivity of ˜21, sufficient band offsets with Si and potential thermal stability in contact with Si. Concurrently, the use of metal electrodes to replace the polycrystalline Si gate electrode has also been of interest for several reasons, including being potentially more thermally stable in contact with the gate dielectric. In HfO2 gate stacks, however, interfacial layers or reaction phases at the Si substrate interface often form. In order to produce optimum devices, a fundamental understanding of the ultrathin (a few A) layers and interfaces in the novel gate stacks is needed and requires a physical characterization tool that can provide atomic-scale resolution. High-angle annular dark-field (HAADF) imaging and electron energy-loss spectroscopy (EELS) in scanning transmission electron microscopy (STEM) have the ability to provide structural and chemical information simultaneously with very high spatial resolution. The application of STEM techniques to gate stack studies showed that (1) chemical profiles across the interfaces may provide compositional information even in stacks with rough interfaces, exact bonding information can be determined from core-loss energy-loss near-edge spectroscopy (ELNES), and (2) spatial resolution may be limited by the probe size, probe spreading, and delocalization. From core-loss ELNES and HAADF, the interfacial layer at the Si/HfO2 interface in stacks with either poly-Si or TiN electrodes was determined to be SiO2 with Hf clusters protruding from the high-kappa into the SiO2 layer. Engineering the Si interface may be possible with the use of AlN overlayers that can control the interface by reducing the SiO2 thickness. Care must be taken for this application since thicker AlN overlayers can lead to complete SiO2 reduction and subsequent Hf-silicide formation.

  4. Prehistorical Pediculus humanus capitis infestation: quantitative data and low vacuum scanning microscopy.

    PubMed

    Dutra, Juliana M F; Alves, Arthur Daniel; Pessanha, Thaila; Rachid, Rachel; Souza, Wanderley de; Linardi, Pedro Marcos; Ferreira, Luiz Fernando; Souza, Sheila Mendonça de; Araujo, Adauto

    2014-01-01

    A pre-Columbian Peruvian scalp was examined decades ago by a researcher from the Oswaldo Cruz Foundation. Professor Olympio da Fonseca Filho described nits and adult lice attached to hair shafts and commented about the origin of head lice infestations on mankind. This same scalp was sent to our laboratory and is the subject of the present paper. Analysis showed a massive infestation with nine eggs/cm2 and an impressive number of very well preserved adult lice. The infestation age was roughly estimated as nine months before death based on the distance of nits from the hair root and the medium rate of hair growth. A small traditional textile was associated with the scalp, possibly part of the funerary belongings. Other morphological aspects visualized by low-vacuum scanning electron microscopy are also presented here for adults and nits. PMID:24626412

  5. PREHISTORICAL Pediculus humanus capitis INFESTATION: QUANTITATIVE DATA AND LOW VACUUM SCANNING MICROSCOPY

    PubMed Central

    Dutra, Juliana M.F.; Alves, Arthur Daniel; Pessanha, Thaila; Rachid, Rachel; de Souza, Wanderley; Linardi, Pedro Marcos; Ferreira, Luiz Fernando; de Souza, Sheila Mendonça; Araujo, Adauto

    2014-01-01

    A pre-Columbian Peruvian scalp was examined decades ago by a researcher from the Oswaldo Cruz Foundation. Professor Olympio da Fonseca Filho described nits and adult lice attached to hair shafts and commented about the origin of head lice infestations on mankind. This same scalp was sent to our laboratory and is the subject of the present paper. Analysis showed a massive infestation with nine eggs/cm2 and an impressive number of very well preserved adult lice. The infestation age was roughly estimated as nine months before death based on the distance of nits from the hair root and the medium rate of hair growth. A small traditional textile was associated with the scalp, possibly part of the funerary belongings. Other morphological aspects visualized by low-vacuum scanning electron microscopy are also presented here for adults and nits. PMID:24626412

  6. Quantitative correlative proton and electron microprobe analysis of biological specimens

    Microsoft Academic Search

    B. Forslind; L. Kunst; K. G. Malmqvist; L. E. Carlsson; G. M. Roomans

    1985-01-01

    Summary  To investigate the possibility of quantitative correlative proton microprobe (PMP) and electron microprobe (EMP) analysis\\u000a of biological soft tissue, model specimens were analyzed by both techniques. The specimens consisted of freeze-dried sections\\u000a of gelatin containing known concentrations of nickel chloride. Both for PMP and for EMP, the signal was expressed as the ratio\\u000a of the characteristic intensity and the continuum

  7. Vortex Matter Research by Electron Microscopy - Memorial to Dr. Akira Tonomura -

    NASA Astrophysics Data System (ADS)

    Harada, K.

    Electron phase microscopy represented by electron holography and Lorentz microscopy, has opened the way to observing a single quantized magnetic flux-line - "vortex" - and its dynamical behavior inside superconductors. It was realized by Dr. Akira Tonomura and his collaborators by developing a field emission electron microscope and by advancing the technologies for visualizing the vortices, for example, low-temperature specimen stage and magnetic-field application system. Electron phase microscopy was clarified to be a powerful tool for investigating the flux-line features inside materials and their configurations with defects. This paper intends to give a review of the research results on vortex matter physics.

  8. Atomic-Scale Imaging and Spectroscopy for In Situ Liquid Scanning Transmission Electron Microscopy

    SciTech Connect

    Jungjohann, K. L.; Evans, James E.; Aguiar, Jeff; Arslan, Ilke; Browning, Nigel D.

    2012-06-04

    Observation of growth, synthesis, dynamics and electrochemical reactions in the liquid state is an important yet largely unstudied aspect of nanotechnology. The only techniques that can potentially provide the insights necessary to advance our understanding of these mechanisms is simultaneous atomic-scale imaging and quantitative chemical analysis (through spectroscopy) under environmental conditions in the transmission electron microscope (TEM). In this study we describe the experimental and technical conditions necessary to obtain electron energy loss (EEL) spectra from a nanoparticle in colloidal suspension using aberration corrected scanning transmission electron microscopy (STEM) combined with the environmental liquid stage. At a fluid path length below 400 nm, atomic resolution images can be obtained and simultaneous compositional analysis can be achieved. We show that EEL spectroscopy can be used to quantify the total fluid path length around the nanoparticle, and demonstrate characteristic core-loss signals from the suspended nanoparticles can be resolved and analyzed to provide information on the local interfacial chemistry with the surrounding environment. The combined approach using aberration corrected STEM and EEL spectra with the in situ fluid stage demonstrates a plenary platform for detailed investigations of solution based catalysis and biological research.

  9. Transmission electron microscopy of magnetite at low temperature Takeshi Kasama1,

    E-print Network

    Dunin-Borkowski, Rafal E.

    understood. We have used conventional and precession electron diffraction in the transmission electronTransmission electron microscopy of magnetite at low temperature Takeshi Kasama1, *, Richard J-Borkowski1 1 Center for Electron Nanoscopy, Technical Univ. of Denmark, Kongens Lyngby, Denmark 2 Dept

  10. Gaseous scintillation detection and amplification in variable pressure scanning electron microscopy

    Microsoft Academic Search

    S. W. Morgan; M. R. Phillips

    2006-01-01

    This work investigates the generation and detection of gaseous scintillation signals produced in variable pressure scanning electron microscopy through electron-gas molecule excitation reactions. Here a gaseous scintillation detection (GSD) system is developed to efficiently detect photons produced via excitation reactions in electron cascades. Images acquired using GSD are compared to those obtained using conventional gaseous secondary electron detection (GSED) and

  11. Creating standards for absolute quantification of Coxiella burnetii in real-time PCR--a comparative study based on transmission electron microscopy.

    PubMed

    Sting, Reinhard; Molz, Kerstin; Hoferer, Marc

    2015-01-01

    Quantitative standards are a prerequisite for quality control and quantification of pathogens. In this study the creation of quantitative standards for use in qPCR is described using the pathogen Coxiella burnetii. Quantification of Coxiella burnetii particles by transmission electron microscopy (TEM) was used as primary standard and compared with data obtained by light microscopy as well as genome equivalents (GE) and plasmid units (recombinant plasmid). Based on pathogen quantification using TEM and light microscopy, pathogen detection limits of 6 and 2 C. burnetii particles could be determined per com1 qPCR reaction, respectively. In comparison, the detection limits were 17 and 13 pathogen units using GE and plasmid units, respectively. The standard generated by TEM can be used as gold standard for universal application due to high accuracy, quantitative control of the producing process and supplying intact pathogen particles. PMID:25465354

  12. High resolution electron microscopy of interfaces in fcc materials

    SciTech Connect

    Merkle, K.L.

    1990-08-01

    Modern high-resolution electron microscopy (HREM) instruments, which are capable of a point-to-point resolution of better than 0.2 nm, have allowed atomic-scale observations of a variety of internal interfaces. The application of the HREM technique to fcc model systems for the purpose of addressing a number of interface issues will be examined in this paper. Atomic structure observations for heterophase interfaces of metal/metal and metal/metal-oxide systems as well as HREM studies of grain boundaries in NiO and Au will be discussed with emphasis on generic structural features and the role of the interface plane. Comparisons between observed interface structures and atomistic computer modeling results have shown agreements for some interfaces, as well as certain differences in others. A number of structural features are common to both metal and oxide grain boundaries, as well as certain heterophase boundaries. Of particular importance in close-packed solids appears to be the tendency to preserve, as much as possible, local atomic coordination, giving rise to atomically well-matched regions that alternate along the interface with regions of misfit. It is commonly observed that heterophase interfaces are being preferentially formed on dense-packed planes. Low-index planes are also frequently observed in asymmetric grain boundaries. In addition to the observation of misfit dislocations in heterophase boundaries, misfit-dislocation-like defects have also been found in asymmetric, incommensurate grain boundaries. The tendency for maintaining coherence between dense-packed planes across the interface has resulted in the formation of novel three-dimensional GB structures. HREM observations have brought new insights into the correlations between macroscopic geometry, interfacial energy, and microscopic atomic relaxations.

  13. Microscopy

    Microsoft Academic Search

    Gwen Lomberk

    2009-01-01

    Microscopy employs the use of microscopes, which are instruments designed to produce magnified visual or photographic images of objects too small to be seen with the naked eye. The goal of the microscope is to accomplish three tasks, namely produce a magnified image of the specimen, separate the details in the image, and render the details visible to the human

  14. Transmission electron microscopy investigation of auto catalyst and cobalt germanide

    NASA Astrophysics Data System (ADS)

    Sun, Haiping

    The modern ceria-zirconia based catalysts are used in automobiles to reduce exhaust pollutants. Cobalt germanides have potential applications as electrical contacts in the future Ge-based semiconductor devices. In this thesis, transmission electron microscopy (TEM) techniques were used to study the atomic scale interactions between metallic nanostructures and crystalline substrates in the two material systems mentioned above. The model catalyst samples consisted of precious metal nano-particles (Pd, Rh) supported on the surface of (Ce,Zr)O2 thin films. The response of the microstructure of the metal-oxide interface to the reduction and oxidation treatments was investigated by cross-sectional high resolution TEM. Atomic detail of the metal-oxide interface was obtained. It was found that Pd and Rh showed different sintering and interaction behaviors on the oxide surface. The preferred orientation of Pd particles in this study was Pd(111)//CZO(111). Partial encapsulation of Pd particles by reduced (Ce,Zr)O 2 surface was observed and possible mechanisms of the encapsulation were discussed. The characteristics of the metal-oxide interaction depend on the properties of the oxide, as well as their relative orientation. The results provide experimental evidence for understanding the thermodynamics of the equilibrium morphology of a solid particle supported on a solid surface that is not considered as inert. The reaction of Co with Ge to form epitaxial Co5Ge7 was studied by in situ ultra-high vacuum (UHV) TEM using two methods. One was reactive deposition of Co on Ge, in which the Ge substrate was maintained at 350°C during deposition. The other method was solid state reaction, in which the deposition of Co on Ge was carried out at room temperature followed by annealing to higher temperatures. During reactive deposition, the deposited Co reacted with Ge to form nanosized 3D Co 5Ge7 islands. During solid state reaction, a continuous epitaxial Co5Ge7 film on the (001) Ge substrate was formed at ˜300°C. With further annealing at a higher temperature, the continuous Co5Ge 7 layer broke into 3D islands in order to relieve the strain energy in the epitaxial Co5Ge7 layer. Electron diffraction and X-ray diffraction were used to identify the cobalt germanide phase and epitaxial orientation relationships with respect to the substrate.

  15. Electron microscopy of plasticity in rat olfactory cortex.

    PubMed

    Westrum, L E

    1988-07-01

    Electron microscopy (EM) is being used to study the ultrastructural basis for the age-dependent reorganization of afferents in the olfactory cortex (OC) of rat after deafferentation of the area by removal of the ipsilateral olfactory bulb (OB). The double-lesion technique was used with a primary lesion of the OB at various postnatal (PN) ages between PN 0 and 30 and in the adult (PN 100). After appropriate survival times to remove initial lesion-degenerated terminals from the OB lesion, a second lesion was placed in the ipsilateral OC. One to 3 days later the tissue is prepared for EM with emphasis on a study of changes in the superficial and deep dendritic layer (Ia and Ib respectively) rostral to the lesion. In control litter mates with both OBs intact, but with a single OC lesion only, degenerating synaptic terminals occur onto dendritic spines and branches only in deeper Ib. However, in adults with OB lesions at PN 0-9, OC lesions produce degenerating terminals throughout Ia and Ib including immediately subjacent to the pia. In Ia degenerating terminals are greatly reduced in the PN 13 group and rare to absent in experiments with OB lesions at older ages (PN 30-100). Electron-dense debris within glia occurs throughout layer I in each double-lesion group but is greatest in experiments with OB lesions at older ages. Some transsynaptic alterations are seen throughout, especially in the PN 30-100 group even at a distance from the OC lesion. The results support earlier light microscopic (LM) findings, suggesting PN 9-13 as critical ages for developmental plasticity and prove that at least in the younger ages, synapses are involved in the phenomenon. This may be explained by either reinnervation of deafferented sites or persistence of synapses that would otherwise have been eliminated by afferents from the OB. In addition, some of the LM degeneration particles probably are engulfed masses of debris and not synaptic structures, especially in cases which were operated at older ages and survived for 3 days. The various afferent pathways involved in the events as well as factors that limit the phenomenon in older ages are discussed. PMID:3409049

  16. Quantitative analyses of Streptococcus mutans biofilms with quartz crystal microbalance, microjet impingement and confocal microscopy

    PubMed Central

    Kreth, J.; Hagerman, E.; Tam, K.; Merritt, J.; Wong, D. T. W.; Wu, B. M.; Myung, N. V.; Shi, W.; Qi, F.

    2005-01-01

    Microbial biofilm formation can be influenced by many physiological and genetic factors. The conventional microtiter plate assay provides useful but limited information about biofilm formation. With the fast expansion of the biofilm research field, there are urgent needs for more informative techniques to quantify the major parameters of a biofilm, such as adhesive strength and total biomass. It would be even more ideal if these measurements could be conducted in a real-time, non-invasive manner. In this study, we used quartz crystal microbalance (QCM) and microjet impingement (MJI) to measure total biomass and adhesive strength, respectively, of S. mutans biofilms formed under different sucrose concentrations. In conjunction with confocal laser scanning microscopy (CLSM) and the COMSTAT software, we show that sucrose concentration affects the biofilm strength, total biomass, and architecture in both qualitative and quantitative manners. Our data correlate well with previous observations about the effect of sucrose on the adherence of S. mutans to the tooth surface, and demonstrate that QCM is a useful tool for studying the kinetics of biofilm formation in real time and that MJI is a sensitive, easy-to-use device to measure the adhesive strength of a biofilm. PMID:16429589

  17. Quantitative Imaging of Rapidly Decaying Evanescent Fields Using Plasmonic Near-Field Scanning Optical Microscopy

    PubMed Central

    Zhang, Zhen; Ahn, Phillip; Dong, Biqin; Balogun, Oluwaseyi; Sun, Cheng

    2013-01-01

    Non-propagating evanescent fields play an important role in the development of nano-photonic devices. While detecting the evanescent fields in far-field can be accomplished by coupling it to the propagating waves, in practice they are measured in the presence of unwanted propagating background components. It leads to a poor signal-to-noise ratio and thus to errors in quantitative analysis of the local evanescent fields. Here we report on a plasmonic near-field scanning optical microscopy (p-NSOM) technique that incorporates a nanofocusing probe for adiabatic focusing of propagating surface plasmon polaritons at the probe apex, and for enhanced coupling of evanescent waves to the far-field. In addition, a harmonic demodulation technique is employed to suppress the contribution of the background. Our experimental results show strong evidence of background free near-field imaging using the new p-NSOM technique. Furthermore, we present measurements of surface plasmon cavity modes, and quantify their contributing sources using an analytical model. PMID:24076563

  18. Nanoparticle interactions with live cells: Quantitative fluorescence microscopy of nanoparticle size effects.

    PubMed

    Shang, Li; Nienhaus, Karin; Jiang, Xiue; Yang, Linxiao; Landfester, Katharina; Mailänder, Volker; Simmet, Thomas; Nienhaus, G Ulrich

    2014-01-01

    Engineered nanomaterials are known to enter human cells, often via active endocytosis. Mechanistic details of the interactions between nanoparticles (NPs) with cells are still not well enough understood. NP size is a key parameter that controls the endocytic mechanism and affects the cellular uptake yield. Therefore, we have systematically analyzed the cellular uptake of fluorescent NPs in the size range of 3.3-100 nm (diameter) by live cells. By using spinning disk confocal microscopy in combination with quantitative image analysis, we studied the time courses of NP association with the cell membrane and subsequent internalization. NPs with diameters of less than 10 nm were observed to accumulate at the plasma membrane before being internalized by the cells. In contrast, larger NPs (100 nm) were directly internalized without prior accumulation at the plasma membrane, regardless of their surface charges. We attribute this distinct size dependence to the requirement of a sufficiently strong local interaction of the NPs with the endocytic machinery in order to trigger the subsequent internalization. PMID:25551067

  19. Microscopy, culture, and quantitative real-time PCR examination confirm internalization of mycobacteria in plants.

    PubMed

    Kaevska, M; Lvoncik, S; Slana, I; Kulich, P; Kralik, P

    2014-07-01

    The environment is a reservoir of nontuberculous mycobacteria and is considered a source of infection for animals and humans. Mycobacteria can persist in different types of environments for a relatively long time. We have studied their possible internalization into plant tissue through intact, as well as damaged, root systems of different types of plants grown in vitro and under field conditions. The substrate into which plants were seeded was previously contaminated with different strains of Mycobacterium avium (10(8) to 10(10) cells/g of soil) and feces from animals with paratuberculosis. We detected M. avium subsp. avium, hominissuis, and paratuberculosis in the stems and leaves of the plants by both culture and real-time quantitative PCR. The presence of mycobacteria in the plant tissues was confirmed by microscopy. The concentration of mycobacteria found inside plant tissue was several orders of magnitude lower (up to 10(4) cells/g of tissue) than the initial concentration of mycobacteria present in the culture medium or substrate. These findings led us to the hypothesis that plants may play a role in the spread and transmission of mycobacteria to other organisms in the environment. PMID:24747896

  20. Quantitative comparison of anti-fading mounting media for confocal laser scanning microscopy.

    PubMed

    Ono, M; Murakami, T; Kudo, A; Isshiki, M; Sawada, H; Segawa, A

    2001-03-01

    Fading is one of the major obstacles to reliable observation in fluorescence microscopy. Using a confocal laser scanning microscope (CLSM) coupled to a computer, we quantitatively measured fading of fluorescence to formulate an equation, evaluated the anti-fading ability of several anti-fading media, and restored the faded images to the original level according to this equation. NIH 3T3 cells were stained with fluorescein isothiocyanate (FITC)-phalloidin, mounted with several commercial and homemade anti-fade media, and observed with CLSM under repeated illumination. With any mounting medium, attenuation of fluorescence intensity at a certain pixel occurred stepwise and the decrease was proportional to the intensity of the previous scan. From these results, we formulated an equation that has three coefficients: anti-fading factor (A), indicating the ability to retard fading; fluorescent intensity at the first scan (EM(1)); and background fluorescence (B). The fluorescent intensity at a certain point following nth scan is given as EM(n) = EM(1) * A ((n-1)). This equation was available for restoring faded images to their original states, even after the image had faded to only 60% of its original intensity. PMID:11181733

  1. Visualization of Microbial Biomarkers by Scanning Electron Microscopy

    NASA Technical Reports Server (NTRS)

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

    2001-01-01

    We are developing tools to link the biochemical structure of selected biomarkers with putative biogenic structures observed in mineralized samples. The detection of evidence of life on Mars and other planets will rely on methods that can discriminate compounds formed exclusively by living organisms. While biogenic compounds, such as amino acids and nucleotides have been discovered in extraterrestrial sources, such as meteorites and comets, their formation can be explained by abiotic means. The formation of cellular structures, or more elaborate organic molecules, such as complex lipids, proteins or nucleic acids, however, is strongly correlated to the presence of even the most primitive life processes. Recent evidence lends support to the hypothesis that life may have once existed on Mars. Carbonate globules and ppm concentrations of polycyclic aromatic hydrocarbons (PAHs) have been described in ALH84001, a meteorite originating from Mars ejecta captured by Earth over 13,000 years ago. The localized high concentration of PAHs that follow an increasing gradient from the intact fusion crust towards the interior corresponds to microgram quantities of hydrocarbon. Even though ALH84001 and other similar meteorites have withstood the forces capable of ejecting rock through Mars' escape velocity, upon entering Earth's atmosphere, their core temperatures are likely not to have been raised significantly, as evidenced by the survival of remanent magnetic signatures. Ideal biomarkers of ancient or modern biological life would include molecules that are (or were) pervasive and highly resistant to degradation. Also, requisite methods of detection should be simple, extremely sensitive and broadly inclusive (NASA SP-530). Lipopolysaccharide (LPS), peptidoglycan or pseudopeptidoglycan and beta-glucan are microbial cell wall components which together cover the entire microbial spectrum of eubacteria, archea and fungi. They are all remarkably resistant to thermal degradation. 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. Computer-controlled scanning electron microscopy: A fast and reliable tool for diamond prospecting

    Microsoft Academic Search

    Nynke Keulen; Mark T. Hutchison; Dirk Frei

    2009-01-01

    Computer-controlled scanning electron microscopy is introduced as a faster, reliably and cost-reducing alternative to conventional electron microprobe analyses on kimberlite indicator minerals. The method is based on conventional scanning electron microscopy and energy dispersive X-ray spectrometry, but due to extended counting times, optimised settings and computer-controlled particle recognition valid data can be obtained on a low amount of operator and

  3. Analytical Electron Microscopy examination of uranium contamination at the DOE Fernald operation site

    SciTech Connect

    Buck, E.C.; Dietz, N.L.; Bates, J.K.; Cunnane, J.C.

    1993-02-01

    Analytical Electron Microscopy (AEM) has been used to identify uranium-bearing phases present in contaminated soils from the DOE Fernald operation site. A combination of optical microscopy, scanning electron microscopy with backscattered electron detection (SEM/BSE), and AEM was used in isolating and characterizing uranium-rich regions of the contaminated soils. Soil samples were prepared for transmission electron microscopy (TEM) by ultramicrotomy using an embedding resin previously employed for aquatic colloids and biological samples. This preparation method allowed direct comparison between SEM and TEM images. At the macroscopic level much of the uranium appears to be associated with clays in the soils; however, electron beam analysis revealed that the uranium is present as discrete phases, including iron oxides, silicates (soddyite), phosphates (autunites), and fluorite. Only low levels of uranium were actually within the clay minerals. The distribution of uranium phases was inhomogeneous at the submicron level.

  4. High-resolution electron microscopy and electron energy-loss spectroscopy of giant palladium clusters

    NASA Astrophysics Data System (ADS)

    Oleshko, V.; Volkov, V.; Gijbels, R.; Jacob, W.; Vargaftik, M.; Moiseev, I.; van Tendeloo, G.

    1995-12-01

    Combined structural and chemical characterization of cationic polynuclear palladium coordination compounds Pd561L60(OAc)180, where L=1,10-phenantroline or 2,2'-bipyridine has been carried out by high-resolution electron microscopy (HREM) and analytical electron microscopy methods including electron energy-loss spectroscopy (EELS), zero-loss electron spectroscopic imaging, and energy-dispersive X-ray spectroscopy (EDX). The cell structure of the cluster matter with almost completely uniform metal core size distributions centered around 2.3 ±0.5 nm was observed. Zero-loss energy filtering allowed to improve the image contrast and resolution. HREM images showed that most of the palladium clusters had a cubo-octahedral shape. Some of them had a distorted icosahedron structure exhibiting multiple twinning. The selected-area electron diffraction patterns confirmed the face centered cubic structure with lattice parameter close to that of metallic palladium. The energy-loss spectra of the populations of clusters contained several bands, which could be assigned to the delayed Pd M4, 5-edge at 362 eV, the Pd M3-edge at 533 eV and the Pd M2-edge at 561 eV, the NK-edge at about 400 eV, the O K-edge at 532 eV overlapping with the Pd M3-edge and the carbon C K-edge at 284 eV. Background subtraction was applied to reveal the exact positions and fine structure of low intensity elemental peaks. EELS evaluations have been confirmed by EDX. The recorded series of the Pd M-edges and the N K-edge in the spectra of the giant palladium clusters obviously were related to Pd-Pd- and Pd-ligand bonding.

  5. Magnetic force microscopy and cross-sectional transmission electron microscopy of carburised surfaces

    Microsoft Academic Search

    K. J Stevens; A Parbhu; J Soltis

    2004-01-01

    Magnetic force microscopy has been used to determine the origin and spatial distribution of changes in magnetic properties of an HPM alloy carburised by exposure in an ethylene production furnace. In higher activity carburising atmospheres at 400–800 °C, metal dusting can occur in which the exposed surface becomes carburised to such an extent that the tube alloy pits and literally

  6. Boron concentration profiling by high angle annular dark field-scanning transmission electron microscopy in homoepitaxial ?-doped diamond layers

    SciTech Connect

    Araújo, D.; Alegre, M. P.; Piñero, J. C. [Dpto Ciencia de los Materiales, Facultad de Ciencias, Universidad de Cádiz, 11510 Puerto Real (Cádiz) (Spain)] [Dpto Ciencia de los Materiales, Facultad de Ciencias, Universidad de Cádiz, 11510 Puerto Real (Cádiz) (Spain); Fiori, A.; Bustarret, E. [Institut Néel, CNRS-Université Joseph Fourier, 25 av. des Martyrs, 38042 Grenoble (France)] [Institut Néel, CNRS-Université Joseph Fourier, 25 av. des Martyrs, 38042 Grenoble (France); Jomard, F. [Groupe d'Etude de la Matière Condensée (GEMaC), UMR 8635 du CNRS, UVSQ, 45 av. des Etats-Unis, 78035 Versailles Cedex (France)] [Groupe d'Etude de la Matière Condensée (GEMaC), UMR 8635 du CNRS, UVSQ, 45 av. des Etats-Unis, 78035 Versailles Cedex (France)

    2013-07-22

    To develop further diamond related devices, the concentration and spatial location of dopants should be controlled down to the nanometer scale. Scanning transmission electron microscopy using the high angle annular dark field mode is shown to be sensitive to boron doping in diamond epilayers. An analytical procedure is described, whereby local boron concentrations above 10{sup 20} cm{sup ?3} were quantitatively derived down to nanometer resolution from the signal dependence on thickness and boron content. Experimental boron local doping profiles measured on diamond p{sup ?}/p{sup ++}/p{sup ?} multilayers are compared to macroscopic profiles obtained by secondary ion mass spectrometry, avoiding reported artefacts.

  7. Electron Microscopy 1.0 Introduction and History

    E-print Network

    Moeck, Peter

    in 1931. · The first Scanning Electron Microscope (SEM) debuted in 1938 ( Von Ardenne) with the first of Results #12;o Electron Microscopes are scientific instruments that use a beam of highly energetic electrons to examine objects on a very fine scale. o Electron Microscopes were developed due

  8. Practical factors affecting the performance of a thin-film phase plate for transmission electron microscopy

    PubMed Central

    Danev, Radostin; Glaeser, Robert M.; Nagayama, Kuniaki

    2011-01-01

    A number of practical issues must be addressed when using thin carbon films as quarter-wave plates for Zernike phase-contrast electron microscopy. We describe, for example, how we meet the more stringent requirements that must be satisfied for beam alignment in this imaging mode. In addition we address the concern that one might have regarding the loss of some of the scattered electrons as they pass through such a phase plate. We show that two easily measured parameters, (1) the low-resolution image contrast produced in cryo-EM images of tobacco mosaic virus particles and (2) the fall-off of the envelope function at high resolution, can be used to quantitatively compare the data quality for Zernike phase-contrast images and for defocused bright-field images. We describe how we prepare carbon-film phase plates that are initially free of charging or other effects that degrade image quality. We emphasize, however, that even though the buildup of hydrocarbon contamination can be avoided by heating the phase plates during use, their performance nevertheless deteriorates over the time scale of days to weeks, thus requiring their frequent replacement in order to maintain optimal performance. PMID:19157711

  9. Stereological characterization of the {gamma}' particles in a nickel base superalloy: Comparison between transmission electron microscopy and atomic force microscopy techniques

    SciTech Connect

    Risbet, M. [Universite de Technologie de Compiegne, Laboratoire Roberval, 60205 Compiegne Cedex (France)], E-mail: marion.risbet@utc.fr; Feaugas, X. [Universite de la Rochelle, L.E.M.M.A., 17042 La Rochelle cedex 01 (France); Guillemer-Neel, C. [Universite Picardie Jules Verne, L.T.R.M.C., 80025 Amiens (France); Clavel, M. [Ecole Centrale Paris, M.S.S.Mat., 92295 Chatenay-Malabry (France)

    2008-09-15

    Critical comparison of transmission electron microscopy and atomic force microscopy techniques was provided concerning size measurements of {gamma}' precipitates in a nickel-base superalloy. The divergence between results is explained in terms of the resolution limit for atomic force microscopy, linked both to the tip dimension and the diameter of the investigated particles.

  10. Quantitative scheme for full-field polarization rotating fluorescence microscopy using a liquid crystal variable retarder

    PubMed Central

    Lesoine, John F.; Youn Lee, Ji; Krogmeier, Jeffrey R.; Kang, Hyeonggon; Clarke, Matthew L.; Chang, Robert; Sackett, Dan L.; Nossal, Ralph; Hwang, Jeeseong

    2012-01-01

    We present a quantitative scheme for full-field polarization rotating fluorescence microscopy. A quarter-wave plate, in combination with a liquid crystal variable retarder, provides a tunable method to rotate polarization states of light prior to its being coupled into a fluorescence microscope. A calibration of the polarization properties of the incident light is performed in order to correct for elliptical polarization states. This calibration allows the response of the sample to linear polarization states of light to be recovered. Three known polarization states of light can be used to determine the average fluorescent dipole orientations in the presence of a spatially varying dc offset or background polarization-invariant fluorescence signal. To demonstrate the capabilities of this device, we measured a series of full-field fluorescence polarization images from fluorescent analogs incorporated in the lipid membrane of Burkitts lymphoma CA46 cells. The fluorescent lipid-like analogs used in this study are molecules that are labeled by either a DiI (1,1?-Dioctadecyl 3,3,3?,3?-Tetramethylindocarbocyanine) fluorophore in its head group or a Bodipy (4,4-difluoro-4-bora-3a,4a-diaza-s-indacene) molecule in its acyl chain. A spatially varying contrast in the normalized amplitude was observed on the cell surface, where the orientation of the DiI molecules is tangential to the cell membrane. The internally labeled cellular structures showed zero response to changes in linear polarization, and the net linear polarization amplitude for these regions was zero. This instrument provides a low cost calibrated method that may be coupled to existing fluorescence microscopes to perform investigations of cellular processes that involve a change in molecular orientations. PMID:22667623

  11. Visualization of macromolecular complexes using cryo-electron microscopy with FEI Tecnai transmission electron microscopes

    PubMed Central

    Grassucci, Robert A; Taylor, Derek; Frank, Joachim

    2009-01-01

    This protocol details the steps used for visualizing the frozen-hydrated grids as prepared following the accompanying protocol entitled ‘Preparation of macromolecular complexes for visualization using cryo-electron microscopy.’ This protocol describes how to transfer the grid to the microscope using a standard cryo-transfer holder or, alternatively, using a cryo-cartridge loading system, and how to collect low-dose data using an FEI Tecnai transmission electron microscope. This protocol also summarizes and compares the various options that are available in data collection for three-dimensional (3D) single-particle reconstruction. These options include microscope settings, choice of detectors and data collection strategies both in situations where a 3D reference is available and in the absence of such a reference (random-conical and common lines). PMID:18274535

  12. Noninvasive Electron Microscopy with Interaction-free Quantum Measurements William P. Putnam and Mehmet Fatih Yanik

    E-print Network

    Yanik, Mehmet Fatih

    Noninvasive Electron Microscopy with Interaction-free Quantum Measurements William P. Putnam, 2009) We propose the use of interaction-free quantum measurements with electrons to eliminate sample and show the possibility of interaction-free measurements with electrons even in the presence of previously

  13. Investigation of Nanoelectrodes by Transmission Electron Microscopy M.S. Kabir1

    E-print Network

    Boyer, Edmond

    or impossible to image with atomic force microscopes (AFM) or Scanning Electron Microscopes (SEM). We have and investigated their properties in transmission electron microscope (TEM) and their electrical characteristicsInvestigation of Nanoelectrodes by Transmission Electron Microscopy M.S. Kabir1 , S.H. Magnus

  14. Investigating the Optical Properties of Dislocations by Scanning Transmission Electron Microscopy

    E-print Network

    Pennycook, Steve

    , Tennessee Summary: The scanning transmission electron microscope (STEM) allows collection of a number (EBIC) modes of the scanning electron microscope (SEM) (Chase and Holt 1973; Datta et al. 1977; DavidsonInvestigating the Optical Properties of Dislocations by Scanning Transmission Electron Microscopy S

  15. Research Grade Remote-Access Scanning Electron Microscopy: The Evolution of the Bugscope Project

    E-print Network

    Illinois at Urbana-Champaign, University of

    to and control of a field emission environmental scanning electron microscope (ESEM) using web browsers-emission environmental scanning electron microscope. Uses for this type of tool include collaborative research projectsResearch Grade Remote-Access Scanning Electron Microscopy: The Evolution of the Bugscope Project

  16. The application of aberration-corrected electron microscopy to the characterization of gold-based catalysts

    Microsoft Academic Search

    Andrew A. Herzing

    2007-01-01

    Electron microscopy has long been used to study the morphology of heterogeneous catalysts. Recent advances in electron optics now allow for the correction of the inherent spherical aberration (Cs) produced by the objective lens in the scanning transmission electron microscope (STEM, resulting in a significantly improved spatial resolution as well as the ability to use a much larger probe-current than

  17. A comparison of calculated images generated by six modes of transmission electron microscopy

    Microsoft Academic Search

    A. Engel; J. W. Wiggins; D. C. Woodruff

    1974-01-01

    Six modes of transmission electron microscopy (TEM) are compared by a numerical simulation of the image formation. The comparison includes five modes of the conventional electron microscope (CEM) (axial bright field, Unwin's phase plate, central stop dark field, tilted beam dark field, conical illumination dark field) and the annular detector mode of the scanning transmission electron microscope (STEM). It is

  18. Vertically integrated optics for ballistic electron emission luminescence: Device and microscopy characterizations

    E-print Network

    Russell, Kasey

    Vertically integrated optics for ballistic electron emission luminescence: Device and microscopy directly into a ballistic electron emission luminescence BEEL heterostructure with GaAs quantum-well active of Physics. DOI: 10.1063/1.2208738 I. INTRODUCTION As a recent development of ballistic electron emission

  19. Morphological properties of pillared layered materials investigated by electron microscopy technique 

    E-print Network

    Navas de Mascianglioli, Margarit

    1993-01-01

    Scanning electron microscopy was used to investigate morphological features of a diverse range of pillared layered materials. Pillared layered zirconium phosphates, zirconium polyimine phosphonates and anion exchanger derivatives, zinc...

  20. EVALUATION OF COMPUTER-CONTROLLED SCANNING ELECTRON MICROSCOPY APPLIED TO AN AMBIENT URBAN AEROSOL SAMPLE

    EPA Science Inventory

    Concerns about the environmental and public health effects of particulate matter (PM) have stimulated interest in analytical techniques capable of measuring the size and chemical composition of individual aerosol particles. Computer-controlled scanning electron microscopy (CCSE...

  1. Development of multiplexing strategies for electron and super-resolution optical microscopy/

    E-print Network

    Tillberg, Paul W

    2013-01-01

    The aim of this work is to increase the multiplexing capabilities of electron and super resolution optical microscopy. This will be done through the development of molecular-scale barcodes that can be resolved in one of ...

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

    EPA Science Inventory

    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...

  3. Engineered ascorbate peroxidase as a genetically encoded reporter for electron microscopy

    E-print Network

    Deerinck, Thomas J

    Electron microscopy (EM) is the standard method for imaging cellular structures with nanometer resolution, but existing genetic tags are inactive in most cellular compartments[superscript 1] or require light and can be ...

  4. A method for the alignment of heterogeneous macromolecules from electron microscopy

    E-print Network

    A method for the alignment of heterogeneous macromolecules from electron microscopy Maxim Shatsky a projection matching approach relies heavily on the structural homogeneity of the macromolecule being studied. Prob- lems arise when the macromolecule exhibits structural flexibility or alternative assemblies

  5. Scanning electron microscopy and epifluorescence investigation of bacterial colonization of marine sand sediments

    Microsoft Academic Search

    W. Weise; G. Rheinheimer

    1977-01-01

    Scanning electron microscopy (SEM) was employed for the investigation of microorganisms living in marine sand sediments. Epifluorescence, as well as sediment analyses, gave further data on the parameters of the sediment samples.

  6. Electron Microscopy of Interactions Between Engineered Nanomaterials and Cells

    E-print Network

    Pala, Nezih

    like free-electron lasers and backward wave oscillators (BWOs). The third is the utilization of optical- rently available THz source technologies, particularly the tunable emitters, such as free-electron lasers

  7. Microwave Procedures for Electron Microscopy and Resin-Embedded Sections

    Microsoft Academic Search

    Anthony S-Y Leong; Raija T Sormunen

    1998-01-01

    Microwaves now have well-established applications in routine light microscopy. They are employed in tissue fixation and to accelerate a wide spectrum of staining procedures. Besides producing superior preservation of cellular antigens through microwave fixation, this form of irradiation has been employed for antigen retrieval, a procedure that has been a major factor in the optimization of immunolabelling in paraffin sections

  8. Determination of mineral distributions in bituminous coals by electron microscopy

    Microsoft Academic Search

    1982-01-01

    In recent transmission electron microscopical studies of coals, ultrafine minerals were observed (<1 ..mu..m). The observation and identity of these submicron minerals would have been difficult to achieve by use of the scanning electron microscope (SEM). However, the scanning transmission electron microscope (STEM) with energy dispersive x-ray analysis is an ideal analytical tool since it is capable of supplying elemental

  9. Structure and magnetism in ultrathin iron oxides characterized by low energy electron microscopy.

    PubMed

    Santos, B; Loginova, E; Mascaraque, A; Schmid, A K; McCarty, K F; de la Figuera, J

    2009-08-01

    We have grown epitaxial films a few atomic layers thick of iron oxides on ruthenium. We characterize the growth by low energy electron microscopy. Using selected-area diffraction and intensity-versus-voltage spectroscopy, we detect two distinct phases which are assigned as wüstite and magnetite. Spin-polarized low energy electron microscopy reveals magnetic domain patterns in the magnetite phase at room temperature. PMID:21828572

  10. Isolation methods and electron microscopy of the Internal Cork Virus of sweet potatoes

    E-print Network

    Pickens, Edgar Eugene

    1967-01-01

    ISOLATION METHODS AND ELECTRON MICROSCOPY OF THE INTERNAL CORK VIRUS OF SWEET POTATOES A Thesis By Edgar Eugene Pickens Submitted to the Graduate College of the Texas A8cM University in partial fulfillment of the requirements for the degree... of MASTER OF SCIENCE August 1967 Major Subject Biochemistry ISOLATION METHODS AND ELECTRON MICROSCOPY OF THE INTERNAL CORK VIRUS OF SWEET POTATOES A Thesis Edgar Eugene Pickens Approved as to style and content by: (Cnairman of Committee) (Head wf...

  11. Enhanced visualization of microbial biofilms by staining and environmental scanning electron microscopy

    Microsoft Academic Search

    John H. Priester; Allison M. Horst; Laurie C. Van De Werfhorst; José L. Saleta; Leal A. K. Mertes; Patricia A. Holden

    2007-01-01

    Bacterial biofilms, i.e. surface-associated cells covered in hydrated extracellular polymeric substances (EPS), are often studied with high-resolution electron microscopy (EM). However, conventional desiccation and high vacuum EM protocols collapse EPS matrices which, in turn, deform biofilm appearances. Alternatively, wet-mode environmental scanning electron microscopy (ESEM) is performed under a moderate vacuum and without biofilm drying. If completely untreated, however, EPS is

  12. Use of electron-microscopy data in receptor models for PM10

    Microsoft Academic Search

    T. G. Dzubay; Y. Mamane

    1989-01-01

    Coarse particles (2.5 to 10 micrometers) were collected in dichotomous samplers and analyzed by scanning electron microscopy and x-ray fluorescence. The resulting data were used in a chemical mass-balance receptor model, and the mass concentration of coarse particles was apportioned into 8 components, which included 2% coal fly ash and 25% botanical matter. Mineral concentrations deduced by electron microscopy were

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

    Microsoft Academic Search

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

    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 series, random conical tilt pairs and ultralarge single-particle data sets. Nevertheless, for ultrahigh-resolution work photographic plates are often still preferred. In

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

    Microsoft Academic Search

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

    2010-01-01

    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 series, random conical tilt pairs and ultralarge single-particle data sets. Nevertheless, for ultrahigh-resolution work photographic plates are often still preferred. In

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

    Microsoft Academic Search

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

    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

  16. Focussed ion beam–transmission electron microscopy applications in ore mineralogy: Bridging micro- and nanoscale observations

    Microsoft Academic Search

    C. L. Ciobanu; N. J. Cook; S. Utsunomiya; A. Pring; L. Green

    2011-01-01

    Focussed ion beam–scanning electron microscopy (FIB–SEM) is a relatively new analytical tool that has been little applied to problems of ore genesis. The technique enables high-resolution (cross-section) imaging and can be used to prepare thinned foils for study by transmission electron microscopy (TEM). FIB–SEM methods applied to sulphides and related compounds represent an in-situ approach for sample characterisation and thus

  17. Studying intracellular transport using high-pressure freezing and Correlative Light Electron Microscopy.

    PubMed

    Brown, Edward; Mantell, Judith; Carter, Debbie; Tilly, Gini; Verkade, Paul

    2009-10-01

    Correlative Light Electron Microscopy (CLEM) aims at combining the best of light and electron microscopy in one experiment. Light microscopy (LM) is especially suited for providing a general overview with data from lots of different cells and by using live cell imaging it can show the history or sequence of events between or inside cells. Electron microscopy (EM) on the other hand can provide a much higher resolution image of a particular event and provide additional spatial information, the so-called reference space. CLEM thus has certain strengths over the application of both LM and EM techniques separately. But combining both modalities however generally also means making compromises in one or both of the techniques. Most often the preservation of ultrastructure for the electron microscopy part is sacrificed. Ideally samples should be visualized in its most native state both in the light microscope as well as the electron microscope. For electron microscopy this currently means that the sample will have to be cryo-fixed instead of the standard chemical fixation. In this paper we will discuss the rationale for using cryofixation for CLEM experiments. In particular we will highlight a CLEM technique using high-pressure freezing in combination with live cell imaging. In addition we examine some of the EM analysis tools that may be useful in combination with CLEM techniques. PMID:19660566

  18. Quantitative analysis of drug-induced complement-mediated cytotoxic effect on single tumor cells using atomic force microscopy and fluorescence microscopy.

    PubMed

    Li, Mi; Liu, Lianqing; Xi, Ning; Wang, Yuechao; Xiao, Xiubin; Zhang, Weijing

    2015-01-01

    In the antibody-based targeted therapies of B-cell lymphomas, complement-mediated cytotoxicity (CMC) is an important mechanism. CMC is activated after the binding of drugs (monoclonal antibodies) to tumor cells. The activation of CMC ultimately leads to the lysis of tumor cells. However, it remains poorly understood how CMC alters the morphology and mechanics of single tumor cells at the nanoscale. In recent years, nanoscopic observations of cellular behaviors with the use of atomic force microscopy (AFM) have contributed much to the field of cell biology. In this work, by combining AFM with fluorescence microscopy, the detailed changes in cellular ultra-microstructures and mechanical properties during the process of CMC were quantitatively investigated on single tumor cells. AFM imaging distinctly showed that the CMC effect could lead to the formation of nano holes on the tumor cells. Quantitative analysis of AFM images indicated that cell surface became lower and rougher after the CMC process. The cellular mechanics measurements showed that during the process of CMC cells firstly softened and finally stiffened, which was validated by dynamically monitoring the mechanical changes of single living cells during CMC. The experimental results provide novel insights into the antibody-dependent CMC. PMID:25420270

  19. Target geometry dependence of electron energy loss spectra in scanning transmission electron microscopy (STEM).

    PubMed

    Rivacoba, A; Aizpurua, J; Zabala, N

    1995-01-01

    In the frame of the Self-Energy formalism, we study the interaction between STEM electrons and small particles in the range of the valence electron excitations. We first calculate the energy loss probability for an isolated sphere and study the loss spectrum dependence on the size of the particle and on the relative impact parameter. Then we analyze the loss spectra in more realistic situations: (a) the effect of the coupling between the particle and supporting surface is studied in a simple geometrical model; and (b) we analyze the dependence of the losses on the geometrical shape of the target by considering hemispherical particle. Our results are in a good qualitative (and in simple cases, quantitative too) agreement with several experimental results which show anomalous excitations. We restate the suitability of the dielectric theory to study the surface excitations of these systems. PMID:8819881

  20. Scanning electron microscopy of the upper urinary tract in transitional cell carcinoma of the renal pelvis.

    PubMed

    Newman, J; Antonakopoulos, G N; Hicks, R M

    1988-08-01

    Three nephrectomy specimens with transitional cell carcinoma (TCC) of the renal pelvis were thoroughly examined by both light and scanning electron microscopy. The tumours as well as the urothelium of the upper urinary tract were studied. In all three cases, extensive areas of the urothelium, even in places remote from the tumours, were found by scanning electron microscopy (SEM) to be covered by pleomorphic microvilli. This suggests that there is a widespread failure of differentiation of the urothelium to a much greater extent than can be appreciated by conventional light microscopy. PMID:3179200