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Sample records for quantitative electron microscopy

  1. Quantitative nanoscale characterisation by electron microscopy

    E-print Network

    Dunin-Borkowski, Rafal E.

    Quantitative nanoscale characterisation by electron microscopy Martin Hÿtch* -- Pascale Bayle of nanoscale devices: strain mapping by high-resolution electron microscopy (HREM), elemental mapping by energy filtered microscopy (EFTEM), and measurements of magnetic and electric fields by electron holography. KEY

  2. Determination of the mass of viruses by quantitative electron microscopy.

    PubMed

    Bahr, G F; Engler, W F; Mazzone, H M

    1976-11-01

    The photometric method of quantitative determination of dry mass by electron microscopy has been applied to the study of various types of viruses: animal, plant, insect, and bacterial. The method is applicable to all viruses having a mass of 1 x 10-18g or greater. The molecular weight of viruses can be calculated from the mass value by multiplying it by Avogadro's number. In comparison to other methods of determining the molecular weight of viruses, sedimentation and diffusion, sedimentation equilibrium, light scattering, and electron microscopy counting, the method of quantitative electron microscopy is competitive. In some ways quantitative electron microscopy is superior to other methods for the determination of molecular weight: There is no limitation to the size of the virus, no experimental time involved and no concentration and purity of virus preparations required, and finally it is independent of the geometry of the virion. In one important aspect it is unique when compared to other methods; namely, it affords one the capacity to analyse individual virus particles. PMID:189345

  3. Quantitative annular dark field electron microscopy using single electron signals.

    PubMed

    Ishikawa, Ryo; Lupini, Andrew R; Findlay, Scott D; Pennycook, Stephen J

    2014-02-01

    One of the difficulties in analyzing atomic resolution electron microscope images is that the sample thickness is usually unknown or has to be fitted from parameters that are not precisely known. An accurate measure of thickness, ideally on a column-by-column basis, parameter free, and with single atom accuracy, would be of great value for many applications, such as matching to simulations. Here we propose such a quantification method for annular dark field scanning transmission electron microscopy by using the single electron intensity level of the detector. This method has the advantage that we can routinely quantify annular dark field images operating at both low and high beam currents, and under high dynamic range conditions, which is useful for the quantification of ultra-thin or light-element materials. To facilitate atom counting at the atomic scale we use the mean intensity in an annular dark field image averaged over a primitive cell, with no free parameters to be fitted. To illustrate the potential of our method, we demonstrate counting the number of Al (or N) atoms in a wurtzite-type aluminum nitride single crystal at each primitive cell over the range of 3-99 atoms. PMID:24168987

  4. Thermal diffuse scattering in sub-angstrom quantitative electron microscopy--phenomenon, effects and approaches

    E-print Network

    Wang, Zhong L.

    Thermal diffuse scattering in sub-angstrom quantitative electron microscopy--phenomenon, effects-resolution transmission electron microscopy, the theoretically calculated images usually give better contrast than, but conventional high-resolution microscopy do contain the contribution made by phonon scattered electrons. (3

  5. Quantitative high resolution electron microscopy of grain boundaries

    SciTech Connect

    Campbell, G.H., King, W.E., Cohen, D., Carter, C.B.

    1996-12-12

    The {Sigma}11 (113)/[1{bar 1}0] symmetric tilt grain boundary has been characterized by high resolution transmission electron microscopy. The method by which the images are prepared for analysis is described. The statistics of the image data have been found to follow a normal distribution. The electron-optical imaging parameters used to acquire the image have been determined by nonlinear least-square image simulation optimization within the perfect crystal region of the micrograph. A similar image simulation optimization procedure is used to determine the atom positions which provide the best match between the experimental image and the image simulation.

  6. Quantitative analysis of mouse corpus callosum from electron microscopy images

    PubMed Central

    West, Kathryn L.; Kelm, Nathaniel D.; Carson, Robert P.; Does, Mark D.

    2015-01-01

    This article provides morphometric analysis of 72 electron microscopy images from control (n=4) and hypomyelinated (n=2) mouse corpus callosum. Measures of axon diameter and g-ratio were tabulated across all brains from two regions of the corpus callosum and a non-linear relationship between axon diameter and g-ratio was observed. These data are related to the accompanying research article comparing multiple methods of measuring g-ratio entitled ‘A revised model for estimating g-ratio from MRI’ (West et al., NeuroImage, 2015). PMID:26504893

  7. Quantitative analysis of mouse corpus callosum from electron microscopy images.

    PubMed

    West, Kathryn L; Kelm, Nathaniel D; Carson, Robert P; Does, Mark D

    2015-12-01

    This article provides morphometric analysis of 72 electron microscopy images from control (n=4) and hypomyelinated (n=2) mouse corpus callosum. Measures of axon diameter and g-ratio were tabulated across all brains from two regions of the corpus callosum and a non-linear relationship between axon diameter and g-ratio was observed. These data are related to the accompanying research article comparing multiple methods of measuring g-ratio entitled 'A revised model for estimating g-ratio from MRI' (West et al., NeuroImage, 2015). PMID:26504893

  8. 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.

  9. Quantitative characterization of epitaxial superlattices by x-ray diffraction and high resolution electron microscopy

    SciTech Connect

    Fullerton, E.E. ); Cao, W.; Thomas, G. ); Schuller, I.K. ); Carey, M.J.; Berkowitz, A.E. )

    1993-07-26

    Quantitative x-ray diffraction (XRD) and high resolution electron microscopy (HREM) have been applied to the analysis of an epitaxial CoO/NiO superlattice. This example shows that the qualitative information determined directly from a XRD spectrum or HREM image is limited and can even be misleading. However, by a combination of quantitative intensity measurements and structural modeling, a detailed quantitative characterization of the superlattice structure is possible.

  10. Electron Microscopy.

    ERIC Educational Resources Information Center

    Beer, Michael

    1980-01-01

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

  11. 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 electron microscopy has resulted from the development of aberration correctors provide an interesting set of challenges for electron microscopy. There is now

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

    SciTech Connect

    Kauko, H.; Helvoort, A. T. J. van; Zheng, C. L.; Glanvill, S.; Zhu, Y.; Etheridge, J.; Dwyer, C.; Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, and Peter Grünberg Institute, Forschungszentrum Jülich, D-52425 Jülich ; Munshi, A. M.; Fimland, B. O.

    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.

  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.

    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 analysis of shadow x-ray magnetic circular dichroism photoemission electron microscopy

    NASA Astrophysics Data System (ADS)

    Jamet, S.; Da, S., Col; Rougemaille, N.; Wartelle, A.; Locatelli, A.; Mente?, T. O.; Santos Burgos, B.; Afid, R.; Cagnon, L.; Bochmann, S.; Bachmann, J.; Fruchart, O.; Toussaint, J. C.

    2015-10-01

    Shadow x-ray magnetic circular dichroism photoemission electron microscopy is a recent technique, in which the photon intensity in the shadow of an object lying on a surface may be used to gather information about the three-dimensional magnetization texture inside the object. Our purpose here is to lay the basis of a quantitative analysis of this technique. We first discuss the principle and implementation of a method to simulate the contrast expected from an arbitrary micromagnetic state. Textbook examples and successful comparison with experiments are then given. Instrumental settings are finally discussed, having an impact on the contrast and spatial resolution: photon energy, microscope extraction voltage and plane of focus, microscope background level, electric-field related distortion of three-dimensional objects, Fresnel diffraction, or photon scattering.

  16. Quantitative Description of Crystal Nucleation and Growth from in Situ Liquid Scanning Transmission Electron Microscopy.

    PubMed

    Ievlev, Anton V; Jesse, Stephen; Cochell, Thomas J; Unocic, Raymond R; Protopopescu, Vladimir A; Kalinin, Sergei V

    2015-12-22

    Recent advances in liquid cell (scanning) transmission electron microscopy (S)TEM has enabled in situ nanoscale investigations of controlled nanocrystal growth mechanisms. Here, we experimentally and quantitatively investigated the nucleation and growth mechanisms of Pt nanostructures from an aqueous solution of K2PtCl6. Averaged statistical, network, and local approaches have been used for the data analysis and the description of both collective particles dynamics and local growth features. In particular, interaction between neighboring particles has been revealed and attributed to reduction of the platinum concentration in the vicinity of the particle boundary. The local approach for solving the inverse problem showed that particles dynamics can be simulated by a stationary diffusional model. The obtained results are important for understanding nanocrystal formation and growth processes and for optimization of synthesis conditions. PMID:26509714

  17. 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

  18. Ultrafast Electron Microscopy

    E-print Network

    Zewail, Ahmed

    Ultrafast Electron Microscopy: Watching Atoms Move and Crystals Melt Garrett K. Drayna and David J provided by electron microscopy and static diffraction patterns provided by X-ray crystallography to infer of human knowledge. Fortunately, that day has arrived with the advent of Ultrafast Electron Microscopy (UEM

  19. Quantitative annular dark field scanning transmission electron microscopy for nanoparticle atom-counting: What are the limits?

    NASA Astrophysics Data System (ADS)

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

    2015-10-01

    Quantitative atomic resolution annular dark field scanning transmission electron microscopy (ADF STEM) has become a powerful technique for nanoparticle atom-counting. However, a lot of nanoparticles provide a severe characterisation challenge because of their limited size and beam sensitivity. Therefore, quantitative ADF STEM may greatly benefit from statistical detection theory in order to optimise the instrumental microscope settings such that the incoming electron dose can be kept as low as possible whilst still retaining single-atom precision. The principles of detection theory are used to quantify the probability of error for atom-counting. This enables us to decide between different image performance measures and to optimise the experimental detector settings for atom-counting in ADF STEM in an objective manner. To demonstrate this, ADF STEM imaging of an industrial catalyst has been conducted using the near-optimal detector settings. For this experiment, we discussed the limits for atomcounting diagnosed by combining a thorough statistical method and detailed image simulations.

  20. High Resolution Quantitative Lorentz Microscopy

    NASA Astrophysics Data System (ADS)

    McVitie, S.; McGrouther, D.; Krajnak, M.

    2015-10-01

    The advent of aberration corrected transmission electron microscopy has led to considerable improvements in the field of high resolution electron microscopy imaging. In this paper we show how these developments are applied to imaging of magnetic structure in field free or low field conditions. Whilst the capability of increased spatial resolution is demonstrated on magnetic layers with a width of < 20nm we also consider how a pixelated detector can be used to dramatically increase the efficiency of the detection of the magnetic signal variation in the presence of strong diffraction contrast.

  1. 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.

  2. Scanning ultrafast electron microscopy

    PubMed Central

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

    2010-01-01

    Progress has been made in the development of four-dimensional ultrafast electron microscopy, which enables space-time imaging of structural dynamics in the condensed phase. In ultrafast electron microscopy, the electrons are accelerated, typically to 200 keV, and the microscope operates in the transmission mode. Here, we report the development of scanning ultrafast electron microscopy using a field-emission-source configuration. Scanning of pulses is made in the single-electron mode, for which the pulse contains at most one or a few electrons, thus achieving imaging without the space-charge effect between electrons, and still in ten(s) of seconds. For imaging, the secondary electrons from surface structures are detected, as demonstrated here for material surfaces and biological specimens. By recording backscattered electrons, diffraction patterns from single crystals were also obtained. Scanning pulsed-electron microscopy with the acquired spatiotemporal resolutions, and its efficient heat-dissipation feature, is now poised to provide in situ 4D imaging and with environmental capability. PMID:20696933

  3. Diagnostic electron microscopy

    SciTech Connect

    Dickersin, G.R.

    1988-01-01

    In this book the author presents a comprehensive reference text on diagnostic electron microscopy. Throughout the book he illustrates how ultrastructural identification can be helpful for the recognition of cell type and the identification of mechanisms of pathogenesis in various diseases. In addition to electron microscopy photographs, there are also numerous light microscopy photographs for comparison. This text presents the classification of neoplasms in the order and arrangement most familiar to the pathologist. Contents: Introduction; Diagram of a Normal Cell; Normal Cell Function; Embryology; Neoplasms; Infectious Agents; Metabolic Diseases; Renal Diseases; Skeletal Muscle and Peripheral Nerve Diseases; Index.

  4. Quantitative Electron Nanodiffraction.

    SciTech Connect

    Spence, John

    2015-01-30

    This Final report summarizes progress under this award for the final reporting period 2002 - 2013 in our development of quantitive electron nanodiffraction to materials problems, especially devoted to atomistic processes in semiconductors and electronic oxides such as the new artificial oxide multilayers, where our microdiffraction is complemented with energy-loss spectroscopy (ELNES) and aberration-corrected STEM imaging (9). The method has also been used to map out the chemical bonds in the important GaN semiconductor (1) used for solid state lighting, and to understand the effects of stacking sequence variations and interfaces in digital oxide superlattices (8). Other projects include the development of a laser-beam Zernike phase plate for cryo-electron microscopy (5) (based on the Kapitza-Dirac effect), work on reconstruction of molecular images using the scattering from many identical molecules lying in random orientations (4), a review article on space-group determination for the International Tables on Crystallography (10), the observation of energy-loss spectra with millivolt energy resolution and sub-nanometer spatial resolution from individual point defects in an alkali halide, a review article for the Centenary of X-ray Diffration (17) and the development of a new method of electron-beam lithography (12). We briefly summarize here the work on GaN, on oxide superlattice ELNES, and on lithography by STEM.

  5. Dynamic Transmission Electron Microscopy

    SciTech Connect

    Evans, James E.; Jungjohann, K. L.; Browning, Nigel D.

    2012-10-12

    Dynamic transmission electron microscopy (DTEM) combines the benefits of high spatial resolution electron microscopy with the high temporal resolution of ultrafast lasers. The incorporation of these two components into a single instrument provides a perfect platform for in situ observations of material processes. However, previous DTEM applications have focused on observing structural changes occurring in samples exposed to high vacuum. Therefore, in order to expand the pump-probe experimental regime to more natural environmental conditions, in situ gas and liquid chambers must be coupled with Dynamic TEM. This chapter describes the current and future applications of in situ liquid DTEM to permit time-resolved atomic scale observations in an aqueous environment, Although this chapter focuses mostly on in situ liquid imaging, the same research potential exists for in situ gas experiments and the successful integration of these techniques promises new insights for understanding nanoparticle, catalyst and biological protein dynamics with unprecedented spatiotemporal resolution.

  6. 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

  7. 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

  8. Structure, ordering, and surfaces of Pt-Fe alloy catalytic nanoparticles from quantitative electron microscopy and X-ray diffraction

    NASA Astrophysics Data System (ADS)

    Chan, Mickey C. Y.; Chen, Liang; Nan, Feihong; Britten, James F.; Bock, Christina; Botton, Gianluigi A.

    2012-10-01

    The current challenge in catalyst development is to produce highly active and economical catalysts. This challenge cannot be overcome without an accurate understanding of catalyst structure, surfaces and morphology as the catalytic reactions occur on the surface active sites. Transmission Electron Microscopy (TEM) is an excellent tool for understanding the structures of the nanoparticles down to the atomic level in determining the relationship with the catalyst's performance in fuel cell applications. This paper describes a detailed structural characterization of Pt-Fe nanoparticles using aberration corrected TEM. Detailed analysis regarding the morphology, structural ordering, facets, nature of the surfaces, atomic displacements and compositions was carried out and presented in the context of their electrochemical performances. In addition, the effects of electrochemical cycling in terms of morphology and composition evolution of the nanoparticles were analyzed. Lastly, along with data from X-ray diffractometry, two different crystallographic models of the unknown Pt3Fe2 nanoparticle phase are proposed. The detailed characterization by TEM provides useful insights into the nanoparticle chemistry and structure that contributes to catalyst development for next generation fuel cells.The current challenge in catalyst development is to produce highly active and economical catalysts. This challenge cannot be overcome without an accurate understanding of catalyst structure, surfaces and morphology as the catalytic reactions occur on the surface active sites. Transmission Electron Microscopy (TEM) is an excellent tool for understanding the structures of the nanoparticles down to the atomic level in determining the relationship with the catalyst's performance in fuel cell applications. This paper describes a detailed structural characterization of Pt-Fe nanoparticles using aberration corrected TEM. Detailed analysis regarding the morphology, structural ordering, facets, nature of the surfaces, atomic displacements and compositions was carried out and presented in the context of their electrochemical performances. In addition, the effects of electrochemical cycling in terms of morphology and composition evolution of the nanoparticles were analyzed. Lastly, along with data from X-ray diffractometry, two different crystallographic models of the unknown Pt3Fe2 nanoparticle phase are proposed. The detailed characterization by TEM provides useful insights into the nanoparticle chemistry and structure that contributes to catalyst development for next generation fuel cells. Electronic supplementary information (ESI) available. See DOI: 10.1039/c2nr31509b

  9. Structure, ordering, and surfaces of Pt-Fe alloy catalytic nanoparticles from quantitative electron microscopy and X-ray diffraction.

    PubMed

    Chan, Mickey C Y; Chen, Liang; Nan, Feihong; Britten, James F; Bock, Christina; Botton, Gianluigi A

    2012-11-21

    The current challenge in catalyst development is to produce highly active and economical catalysts. This challenge cannot be overcome without an accurate understanding of catalyst structure, surfaces and morphology as the catalytic reactions occur on the surface active sites. Transmission Electron Microscopy (TEM) is an excellent tool for understanding the structures of the nanoparticles down to the atomic level in determining the relationship with the catalyst's performance in fuel cell applications. This paper describes a detailed structural characterization of Pt-Fe nanoparticles using aberration corrected TEM. Detailed analysis regarding the morphology, structural ordering, facets, nature of the surfaces, atomic displacements and compositions was carried out and presented in the context of their electrochemical performances. In addition, the effects of electrochemical cycling in terms of morphology and composition evolution of the nanoparticles were analyzed. Lastly, along with data from X-ray diffractometry, two different crystallographic models of the unknown Pt(3)Fe(2) nanoparticle phase are proposed. The detailed characterization by TEM provides useful insights into the nanoparticle chemistry and structure that contributes to catalyst development for next generation fuel cells. PMID:23076640

  10. A quantitative estimation of the exhaust, abrasion and resuspension components of particulate traffic emissions using electron microscopy

    NASA Astrophysics Data System (ADS)

    Weinbruch, Stephan; Worringen, Annette; Ebert, Martin; Scheuvens, Dirk; Kandler, Konrad; Pfeffer, Ulrich; Bruckmann, Peter

    2014-12-01

    The contribution of the three traffic-related components exhaust, abrasion, and resuspension to kerbside and urban background PM10 and PM1 levels was quantified based on the analysis of individual particles by scanning electron microscopy. A total of 160 samples was collected on 38 days between February and September 2009 at a kerbside and an urban background station in the urban/industrial Ruhr area (Germany). Based on size, morphology, chemical composition and stability under electron bombardment, the 111,003 particles studied in detail were classified into the following 14 particle classes: traffic/exhaust, traffic/abrasion, traffic/resuspension, carbonaceous/organic, industry/metallurgy, industry/power plants, secondary particles, (aged) sea salt, silicates, Ca sulfates, carbonates, Fe oxides/hydroxides, biological particles, and other particles. The traffic/exhaust component consists predominantly of externally mixed soot particles and soot internally mixed with secondary particles. The traffic/abrasion component contains all particles with characteristic tracer elements (Fe, Cu, Ba, Sb, Zn) for brake and tire abrasion. The traffic/resuspension component is defined by the mixing state and comprises all internally mixed particles with a high proportion of silicates or Fe oxides/hydroxides which contain soot or abrasion particles as minor constituent. In addition, silicates and Fe oxides/hydroxides internally mixed with chlorine and sulphur containing particles were also assigned to the traffic/resuspension component. The total contribution of traffic to PM10 was found to be 27% at the urban background station and 48% at the kerbside station, the corresponding values for PM1 are 15% and 39%. These values lie within the range reported in previous literature. The relative share of the different traffic components for PM10 at the kerbside station was 27% exhaust, 15% abrasion, and 58% resuspension (38%, 8%, 54% for PM1). For the urban background, the following relative shares were obtained for PM10: 22% exhaust, 22% abrasion and 56% resuspension (40%, 27%, 33% for PM1). Compared to previous publications we have observed a significantly lower portion of exhaust particles and a significantly higher portion of resuspension particles. The high abundance of resuspension particles underlines their significance for the observed adverse health effects of traffic emissions and for mitigation measures.

  11. Quantitative analysis on volcanic ash surfaces: application of extended depth-of-field (focus) algorithm for light and scanning electron microscopy and 3D reconstruction.

    PubMed

    Ersoy, Orkun; Aydar, Erkan; Gourgaud, Alain; Bayhan, Hasan

    2008-01-01

    The depth-of-field mainly affects the image quality either in scanning electron microscopy (SEM) or conventional light microscopy. The limited depth-of-field handicap of microscopy imaging can be used for obtaining "optically sectioned" specimens by moving the object along the optical axis. In this study, multiple images corresponding to different object planes were taken in order to overcome limited depth-of-field on conventional light microscope and SEM, estimation of an elevation surface and 3D reconstruction of different type volcanic ash surfaces. We used extended depth-of-field, a fusion algorithm that combines those images into one single sharp composite. Because of larger depth-of-field, we got higher-quality results even with image stacks taken by SEM with a fixed aperture in variable pressure mode. We calculated roughness descriptors, quadtree decomposition and greylevel standard deviation (sGL) and analyzed the shape of polar plots based on gradient analysis of constructed depth-maps. Furthermore, we calculated fractal dimensions of surfaces. Correlation analysis was performed to measure how these quantitative variables are related with different type ash surfaces. Roughness descriptors, quadtree decomposition, sGL and fractal dimension discriminate different types of volcanic ash surfaces. PMID:17208002

  12. High speed quantitative digital microscopy

    NASA Technical Reports Server (NTRS)

    Castleman, K. R.; Price, K. H.; Eskenazi, R.; Ovadya, M. M.; Navon, M. A.

    1984-01-01

    Modern digital image processing hardware makes possible quantitative analysis of microscope images at high speed. This paper describes an application to automatic screening for cervical cancer. The system uses twelve MC6809 microprocessors arranged in a pipeline multiprocessor configuration. Each processor executes one part of the algorithm on each cell image as it passes through the pipeline. Each processor communicates with its upstream and downstream neighbors via shared two-port memory. Thus no time is devoted to input-output operations as such. This configuration is expected to be at least ten times faster than previous systems.

  13. 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.

  14. 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.

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

    E-print Network

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

  16. From quantitative microscopy to automated image understanding

    E-print Network

    Murphy, Robert F.

    Mar. 9, 2004. 1 Introduction Biomedical research has been revolutionized by the new typesFrom quantitative microscopy to automated image understanding Kai Huang Robert F. Murphy Carnegie processing of digitized images. Although many of the latest digital signal processing techniques have been

  17. 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

  18. Quantitative characterization of virus-like particles by asymmetrical flow field flow fractionation, electrospray differential mobility analysis, and transmission electron microscopy.

    PubMed

    Pease, Leonard F; Lipin, Daniel I; Tsai, De-Hao; Zachariah, Michael R; Lua, Linda H L; Tarlov, Michael J; Middelberg, Anton P J

    2009-02-15

    Here we characterize virus-like particles (VLPs) by three very distinct, orthogonal, and quantitative techniques: electrospray differential mobility analysis (ES-DMA), asymmetric flow field-flow fractionation with multi-angle light scattering detection (AFFFF-MALS) and transmission electron microscopy (TEM). VLPs are biomolecular particles assembled from viral proteins with applications ranging from synthetic vaccines to vectors for delivery of gene and drug therapies. VLPs may have polydispersed, multimodal size distributions, where the size distribution can be altered by subtle changes in the production process. These three techniques detect subtle size differences in VLPs derived from the non-enveloped murine polyomavirus (MPV) following: (i) functionalization of the surface of VLPs with an influenza viral peptide fragment; (ii) packaging of foreign protein internally within the VLPs; and (iii) packaging of genomic DNA internally within the VLPs. These results demonstrate that ES-DMA and AFFFF-MALS are able to quantitatively determine VLP size distributions with greater rapidity and statistical significance than TEM, providing useful technologies for product development and process analytics. PMID:18958863

  19. Soil microstructure and electron microscopy

    NASA Technical Reports Server (NTRS)

    Smart, P.; Fryer, J. R.

    1988-01-01

    As part of the process of comparing Martian soils with terrestial soils, high resolution electron microscopy and associated techniques should be used to examine the finer soil particles, and various techniques of electron and optical microscopy should be used to examine the undisturbed structure of Martian soils. To examine the structure of fine grained portions of the soil, transmission electron microscopy may be required. A striking feature of many Martian soils is their red color. Although the present-day Martian climate appears to be cold, this color is reminiscent of terrestial tropical red clays. Their chemical contents are broadly similar.

  20. Quantitative analysis of the myelin g-ratio from electron microscopy images of the macaque corpus callosum

    PubMed Central

    Stikov, Nikola; Campbell, Jennifer S.W.; Stroh, Thomas; Lavelée, Mariette; Frey, Stephen; Novek, Jennifer; Nuara, Stephen; Ho, Ming-Kai; Bedell, Barry J.; Dougherty, Robert F.; Leppert, Ilana R.; Boudreau, Mathieu; Narayanan, Sridar; Duval, Tanguy; Cohen-Adad, Julien; Picard, Paul-Alexandre; Gasecka, Alicja; Côté, Daniel; Pike, G. Bruce

    2015-01-01

    We provide a detailed morphometric analysis of eight transmission electron micrographs (TEMs) obtained from the corpus callosum of one cynomolgus macaque. The raw TEM images are included in the article, along with the distributions of the axon caliber and the myelin g-ratio in each image. The distributions are analyzed to determine the relationship between axon caliber and g-ratio, and compared against the aggregate metrics (myelin volume fraction, fiber volume fraction, and the aggregate g-ratio), as defined in the accompanying research article entitled ‘In vivo histology of the myelin g-ratio with magnetic resonance imaging’ (Stikov et al., NeuroImage, 2015). PMID:26217818

  1. Electronic Blending in Virtual Microscopy

    ERIC Educational Resources Information Center

    Maybury, Terrence S.; Farah, Camile S.

    2010-01-01

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

  2. 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.

  3. Effects of non-rotationally symmetric aberrations on the quantitative measurement of lattice positions in a graphene monolayer using high-resolution transmission electron microscopy.

    PubMed

    Lin, Fang; Jian, Jiajun; Ye, Lvshan; Jin, Chuanhong

    2015-10-01

    It is crucial to determine the position of lattice atoms in a monolayer specimen with high precision using high-resolution transmission electron microscopy (HRTEM). Image simulations indicate that the intensity centers of periodic lattice atoms in graphene may deviate from their intrinsic positions if non-rotationally symmetric aberrations (except for three-fold and six-fold aberrations) exist in the HRTEM imaging system. In this letter, we quantitatively compared the deviations caused by non-rotationally symmetric aberrations, which are equivalent to individually produce a ?/4 phase shift in the wave aberration function at a given frequency of 7.2 nm(-1). A two-fold aberration caused a maximum shift of 0.3 Å, and in the images affected by the axial coma, graphene still maintained its hexagonal structure while all of the measured atomic positions deviated. Furthermore, we discovered that atoms on each sublattice tended to shift by similar distances in the image. Based on this rule, we retrieved the intrinsic bond length between neighboring carbon atoms by 'shifting' the measured atom positions in an experimental HRTEM image affected by residual aberrations. PMID:26070475

  4. Aberration corrected Lorentz scanning transmission electron microscopy.

    PubMed

    McVitie, S; McGrouther, D; McFadzean, S; MacLaren, D A; O'Shea, K J; Benitez, M J

    2015-05-01

    We present results from an aberration corrected scanning transmission electron microscope which has been customised for high resolution quantitative Lorentz microscopy with the sample located in a magnetic field free or low field environment. We discuss the innovations in microscope instrumentation and additional hardware that underpin the imaging improvements in resolution and detection with a focus on developments in differential phase contrast microscopy. Examples from materials possessing nanometre scale variations in magnetisation illustrate the potential for aberration corrected Lorentz imaging as a tool to further our understanding of magnetism on this lengthscale. PMID:25677688

  5. Quantitative fluorescence microscopy and image deconvolution.

    PubMed

    Swedlow, Jason R

    2013-01-01

    Quantitative imaging and image deconvolution have become standard techniques for the modern cell biologist because they can form the basis of an increasing number of assays for molecular function in a cellular context. There are two major types of deconvolution approaches--deblurring and restoration algorithms. Deblurring algorithms remove blur but treat a series of optical sections as individual two-dimensional entities and therefore sometimes mishandle blurred light. Restoration algorithms determine an object that, when convolved with the point-spread function of the microscope, could produce the image data. The advantages and disadvantages of these methods are discussed in this chapter. Image deconvolution in fluorescence microscopy has usually been applied to high-resolution imaging to improve contrast and thus detect small, dim objects that might otherwise be obscured. Their proper use demands some consideration of the imaging hardware, the acquisition process, fundamental aspects of photon detection, and image processing. This can prove daunting for some cell biologists, but the power of these techniques has been proven many times in the works cited in the chapter and elsewhere. Their usage is now well defined, so they can be incorporated into the capabilities of most laboratories. A major application of fluorescence microscopy is the quantitative measurement of the localization, dynamics, and interactions of cellular factors. The introduction of green fluorescent protein and its spectral variants has led to a significant increase in the use of fluorescence microscopy as a quantitative assay system. For quantitative imaging assays, it is critical to consider the nature of the image-acquisition system and to validate its response to known standards. Any image-processing algorithms used before quantitative analysis should preserve the relative signal levels in different parts of the image. A very common image-processing algorithm, image deconvolution, is used to remove blurred signal from an image. There are two major types of deconvolution approaches, deblurring and restoration algorithms. Deblurring algorithms remove blur, but treat a series of optical sections as individual two-dimensional entities, and therefore sometimes mishandle blurred light. Restoration algorithms determine an object that, when convolved with the point-spread function of the microscope, could produce the image data. The advantages and disadvantages of these methods are discussed. PMID:23931516

  6. Quantitative Aspects of Single Molecule Microscopy

    PubMed Central

    Ober, Raimund J.; Tahmasbi, Amir; Ram, Sripad; Lin, Zhiping; Ward, E. Sally

    2015-01-01

    Single molecule microscopy is a relatively new optical microscopy technique that allows the detection of individual molecules such as proteins in a cellular context. This technique has generated significant interest among biologists, biophysicists and biochemists, as it holds the promise to provide novel insights into subcellular processes and structures that otherwise cannot be gained through traditional experimental approaches. Single molecule experiments place stringent demands on experimental and algorithmic tools due to the low signal levels and the presence of significant extraneous noise sources. Consequently, this has necessitated the use of advanced statistical signal and image processing techniques for the design and analysis of single molecule experiments. In this tutorial paper, we provide an overview of single molecule microscopy from early works to current applications and challenges. Specific emphasis will be on the quantitative aspects of this imaging modality, in particular single molecule localization and resolvability, which will be discussed from an information theoretic perspective. We review the stochastic framework for image formation, different types of estimation techniques and expressions for the Fisher information matrix. We also discuss several open problems in the field that demand highly non-trivial signal processing algorithms. PMID:26167102

  7. 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.

  8. Dynamic imaging with electron microscopy

    SciTech Connect

    Campbell, Geoffrey; McKeown, Joe; Santala, Melissa

    2014-02-20

    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.

  9. Prototype cantilevers for quantitative lateral force microscopy

    SciTech Connect

    Reitsma, Mark G.; Gates, Richard S.; Friedman, Lawrence H.; Cook, Robert F.

    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.

  10. Direct imaging of crystal structure and defects in metastable Ge2Sb2Te5 by quantitative aberration-corrected scanning transmission electron microscopy

    NASA Astrophysics Data System (ADS)

    Ross, Ulrich; Lotnyk, Andriy; Thelander, Erik; Rauschenbach, Bernd

    2014-03-01

    Knowledge about the atomic structure and vacancy distribution in phase change materials is of foremost importance in order to understand the underlying mechanism of fast reversible phase transformation. In this Letter, by combining state-of-the-art aberration-corrected scanning transmission electron microscopy with image simulations, we are able to map the local atomic structure and composition of a textured metastable Ge2Sb2Te5 thin film deposited by pulsed laser deposition with excellent spatial resolution. The atomic-resolution scanning transmission electron microscopy investigations display the heterogeneous defect structure of the Ge2Sb2Te5 phase. The obtained results are discussed. Highly oriented Ge2Sb2Te5 thin films appear to be a promising approach for further atomic-resolution investigations of the phase change behavior of this material class.

  11. 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

  12. 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

  13. ELECTRON MICROSCOPY IN THE CONTEXT OF STRUCTURAL

    E-print Network

    Bourne, Philip E.

    6 ELECTRON MICROSCOPY IN THE CONTEXT OF STRUCTURAL SYSTEMS BIOLOGY Niels Volkmann and Dorit Hanein andcomputational techniques, electron microscopy has matured into a powerful and diverse collection of methods and multicomponent cellular machinery close to physiological conditions is possible using electron microscopy

  14. Correlative Stochastic Optical Reconstruction Microscopy and Electron Microscopy

    PubMed Central

    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

  15. Low-magnification Quantitative X-ray Mapping of Grain-boundary Segregation in Aluminum-4 wt.% Copper by Analytical Electron Microscopy.

    PubMed

    Carpenter; Watanabe; Barmak; Williams

    1999-07-01

    : Quantitative X-ray mapping in the analytical electron microscope (AEM) could improve the statistics of grain-boundary segregation measurements if high spatial resolution can be maintained at lower magnifications (<500 kX). Typically, only about 10 boundaries are analyzed because of the difficulty of conventional AEM measurements; however, a low-magnification quantitative X-ray map could contain twice this number of boundaries in a single field of view. Microscope conditions and mapping parameters have been explored for operation at approximately 250 kX, under a variety of conditions to illustrate the trade-offs between various characteristics, such as analytical resolution, counting statistics, magnification, and acquisition time. From these data, it is possible to extrapolate to maps generated under different conditions and estimate their limitations with respect to these characteristics. A simple model has been developed to describe the behavior of inclined grain boundaries that can be used to estimate the detectability of segregant as a function of boundary tilt. Using quantitative X-ray maps, grain boundary Cu coverage has been measured from 55 boundaries in Al-4 wt.% Cu with minimal user effort. For fine-grained thin films, mapping is substantially more efficient than other methods of data acquisition and may be used to measure segregation at large numbers of boundaries. PMID:10421810

  16. Atomic Force and Scanning Electron Microscopy of Atmospheric Particles

    E-print Network

    Shapira, Yoram

    Atomic Force and Scanning Electron Microscopy of Atmospheric Particles ZAHAVA BARKAY,1 * AMIT 69978, Israel KEY WORDS atmospheric aerosols; atomic force microscopy; scanning electron microscopy; energy dispersive spectroscopy ABSTRACT Atomic force microscopy (AFM) and scanning electron microscopy

  17. Scanning Electron Microscopy (SEM) Facility Manager

    E-print Network

    MacIver, Malcolm A.

    Scanning Electron Microscopy (SEM) Facility Manager Position Available The NUANCE Center at Northwestern University. The SEM Facility Manager oversees all aspects of the Scanning Electron Microscopy (SEM. In addition to microscopy tasks, the instruments in the SEM facility are also used for nanofabrication via

  18. Quantitative analysis of the nanoscale intra-nuclear structural alterations in hippocampal cells in chronic alcoholism via transmission electron microscopy study

    E-print Network

    Sahay, Peeyush; Ghimire, Hemendra M; Almabadi, Huda; Tripathi, Vibha; Mohanty, Samarendra K; Rao, Radhakrishna; Pradhan, Prabhakar

    2015-01-01

    Chronic alcoholism is known to alter morphology of hippocampal, an important region of cognitive function in the brain. We performed quantification of nanoscale structural alterations in nuclei of hippocampal neuron cells due to chronic alcoholism, in mice model. Transmission electron microscopy images of the neuron cells were obtained and the degrees of structural alteration, in terms of mass density fluctuations, were determined using the recently developed light localization analysis technique. The results, obtained at the length scales ranging from 33 to 195 nm, show that the 4-week alcohol fed mice have higher degree of structural alteration in comparison to the control mice. The degree of structural alterations starts becoming significantly distinguishable around 100 nm sample length, which is the typical length scale of the building blocks of cells, such as DNA, RNA, etc. Different degrees of structural alterations at such length scales suggest possible structural rearrangement of chromatin inside the ...

  19. Parallel Simulation of ElectronSolid Interactions Electron Microscopy Modeling

    E-print Network

    Plimpton, Steve

    Page 1 Parallel Simulation of Electron­Solid Interactions for Electron Microscopy Modeling S. J, Monte Carlo, electron, microscopy, random number generation Abstract A parallel implementation Introduction Analytical electron microscopy (AEM) is a tool for characterizing the spatial distribution of ele

  20. Four-dimensional ultrafast electron microscopy

    PubMed Central

    Lobastov, Vladimir A.; Srinivasan, Ramesh; Zewail, Ahmed H.

    2005-01-01

    Electron microscopy is arguably the most powerful tool for spatial imaging of structures. As such, 2D and 3D microscopies provide static structures with subnanometer and increasingly with ångstrom-scale spatial resolution. Here we report the development of 4D ultrafast electron microscopy, whose capability imparts another dimension to imaging in general and to dynamics in particular. We demonstrate its versatility by recording images and diffraction patterns of crystalline and amorphous materials and images of biological cells. The electron packets, which were generated with femtosecond laser pulses, have a de Broglie wavelength of 0.0335 Å at 120 keV and have as low as one electron per pulse. With such few particles, doses of few electrons per square ångstrom, and ultrafast temporal duration, the long sought after but hitherto unrealized quest for ultrafast electron microscopy has been realized. Ultrafast electron microscopy should have an impact on all areas of microscopy, including biological imaging. PMID:15883380

  1. Lock-in thermography, penetrant inspection, and scanning electron microscopy for quantitative evaluation of open micro-cracks at the tooth-restoration interface

    NASA Astrophysics Data System (ADS)

    Streza, M.; Hodisan, I.; Prejmerean, C.; Boue, C.; Tessier, Gilles

    2015-03-01

    The evaluation of a dental restoration in a non-invasive way is of paramount importance in clinical practice. The aim of this study was to assess the minimum detectable open crack at the cavity-restorative material interface by the lock-in thermography technique, at laser intensities which are safe for living teeth. For the analysis of the interface, 18 box-type class V standardized cavities were prepared on the facial and oral surfaces of each tooth, with coronal margins in enamel and apical margins in dentine. The preparations were restored with the Giomer Beautifil (Shofu) in combination with three different adhesive systems. Three specimens were randomly selected from each experimental group and each slice has been analysed by visible, infrared (IR), and scanning electron microscopy (SEM). Lock-in thermography showed the most promising results in detecting both marginal and internal defects. The proposed procedure leads to a diagnosis of micro-leakages having openings of 1?µm, which is close to the diffraction limit of the IR camera. Clinical use of a thermographic camera in assessing the marginal integrity of a restoration becomes possible. The method overcomes some drawbacks of standard SEM or dye penetration testing. The results support the use of an IR camera in dentistry, for the diagnosis of micro-gaps at bio-interfaces.

  2. Quantitative transmission electron microscopy analysis of multi-variant grains in present L10-FePt based heat assisted magnetic recording media

    NASA Astrophysics Data System (ADS)

    Ho, Hoan; Zhu, Jingxi; Kulovits, Andreas; Laughlin, David E.; Zhu, Jian-Gang

    2014-11-01

    We present a study on atomic ordering within individual grains in granular L10-FePt thin films using transmission electron microscopy techniques. The film, used as a medium for heat assisted magnetic recording, consists of a single layer of FePt grains separated by non-magnetic grain boundaries and is grown on an MgO underlayer. Using convergent-beam techniques, diffraction patterns of individual grains are obtained for a large number of crystallites. The study found that although the majority of grains are ordered in the perpendicular direction, more than 15% of them are multi-variant, or of in-plane c-axis orientation, or disordered fcc. It was also found that these multi-variant and in-plane grains have always grown across MgO grain boundaries separating two or more MgO grains of the underlayer. The in-plane ordered portion within a multi-variant L10-FePt grain always lacks atomic coherence with the MgO directly underneath it, whereas, the perpendicularly ordered portion is always coherent with the underlying MgO grain. Since the existence of multi-variant and in-plane ordered grains are severely detrimental to high density data storage capability, the understanding of their formation mechanism obtained here should make a significant impact on the future development of hard disk drive technology.

  3. Quantitative transmission electron microscopy analysis of multi-variant grains in present L1{sub 0}-FePt based heat assisted magnetic recording media

    SciTech Connect

    Ho, Hoan; Zhu, Jingxi; Kulovits, Andreas; Laughlin, David E.; Zhu, Jian-Gang

    2014-11-21

    We present a study on atomic ordering within individual grains in granular L1{sub 0}-FePt thin films using transmission electron microscopy techniques. The film, used as a medium for heat assisted magnetic recording, consists of a single layer of FePt grains separated by non-magnetic grain boundaries and is grown on an MgO underlayer. Using convergent-beam techniques, diffraction patterns of individual grains are obtained for a large number of crystallites. The study found that although the majority of grains are ordered in the perpendicular direction, more than 15% of them are multi-variant, or of in-plane c-axis orientation, or disordered fcc. It was also found that these multi-variant and in-plane grains have always grown across MgO grain boundaries separating two or more MgO grains of the underlayer. The in-plane ordered portion within a multi-variant L1{sub 0}-FePt grain always lacks atomic coherence with the MgO directly underneath it, whereas, the perpendicularly ordered portion is always coherent with the underlying MgO grain. Since the existence of multi-variant and in-plane ordered grains are severely detrimental to high density data storage capability, the understanding of their formation mechanism obtained here should make a significant impact on the future development of hard disk drive technology.

  4. Quantitative phase measurements using optical quadrature microscopy.

    PubMed

    Rockward, Willie S; Thomas, Anthony L; Zhao, Bing; Dimarzio, Charles A

    2008-04-01

    Imaging of phase or optical path length is becoming more important with the development of better imaging systems, computational algorithms, faster computers, and a greater interest in the imaging of transparent objects. Early phase imaging involved qualitative imaging of phase gradients. New computational algorithms can be used to extract some quantitative phase imaging from these techniques. In contrast, new hardware has enabled full-field quantitative phase imaging on a practical and cost-effective scale. We explore a quantitative comparison between two techniques for imaging phase. In the first technique, phase is recovered from a pair of differential interference contrast images, and in the second technique, phase is measured pixel-by-pixel interferometrically. It is shown, experimentally, that the overall results are similar, but each technique has its own advantages and disadvantages. PMID:18382601

  5. Correlative light and electron microscopy using cathodoluminescence from

    E-print Network

    Walsworth, Ronald L.

    Correlative light and electron microscopy using cathodoluminescence from nanoparticles 02138. Correlative light and electron microscopy promises to combine molecular specificity in a single instrument. T he correlation of light microscopy with electron microscopy offers considerable

  6. Opportunities for Chromatic Aberration Corrected High-Resolution Transmission Electron Microscopy, Lorentz Microscopy and Electron

    E-print Network

    Dunin-Borkowski, Rafal E.

    Opportunities for Chromatic Aberration Corrected High-Resolution Transmission Electron Microscopy, Lorentz Microscopy and Electron Holography of Magnetic Minerals R. E. Dunin-Borkowski1 , T. Kasama2 , R. J. Jinschek4 1 Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Peter Grünberg Institute

  7. Proximity Scanning Transmission Electron Microscopy/Spectroscopy

    E-print Network

    Hwang, Ing-Shouh

    2016-01-01

    Here a new microscopic method is proposed to image and characterize very thin samples like few-layer materials, organic molecules, and nanostructures with nanometer or sub-nanometer resolution using electron beams of energies lower than 20 eV. The microscopic technique achieves high resolution through the proximity (or near-field) effect, as in scanning tunneling microscopy (STM), while it also allows detection of transmitted electrons for imaging and spectroscopy, as in scanning transmission electron microscopy (STEM). This proximity transmission electron microscopy (PSTEM) does not require any lens to focus the electron beam. It also allows detailed characterization of the interaction of low-energy electron with materials. PSTEM can operate in a way very similar to scanning tunneling microscopy, which provides high-resolution imaging of geometric and electronic structures of the sample surface. In addition, it allows imaging and characterization of the interior structures of the sample based on the detected...

  8. Advance in orientation microscopy: quantitative analysis of nanocrystalline structures.

    PubMed

    Seyring, Martin; Song, Xiaoyan; Rettenmayr, Markus

    2011-04-26

    The special properties of nanocrystalline materials are generally accepted to be a consequence of the high density of planar defects (grain and twin boundaries) and their characteristics. However, until now, nanograin structures have not been characterized with similar detail and statistical relevance as coarse-grained materials, due to the lack of an appropriate method. In the present paper, a novel method based on quantitative nanobeam diffraction in transmission electron microscopy (TEM) is presented to determine the misorientation of adjacent nanograins and subgrains. Spatial resolution of <5 nm can be achieved. This method is applicable to characterize orientation relationships in wire, film, and bulk materials with nanocrystalline structures. As a model material, nanocrystalline Cu is used. Several important features of the nanograin structure are discovered utilizing quantitative analysis: the fraction of twin boundaries is substantially higher than that observed in bright-field images in the TEM; small angle grain boundaries are prominent; there is an obvious dependence of the grain boundary characteristics on grain size distribution and mean grain size. PMID:21375327

  9. Atomic resolution 3D electron diffraction microscopy

    SciTech Connect

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

    2002-03-01

    Electron lens aberration is the major barrier limiting the resolution of electron microscopy. Here we describe a novel form of electron microscopy to overcome electron lens aberration. By combining coherent electron diffraction with the oversampling phasing method, we show that the 3D structure of a 2 x 2 x 2 unit cell nano-crystal (framework of LTA [Al12Si12O48]8) can be ab initio determined at the resolution of 1 Angstrom from a series of simulated noisy diffraction pattern projections with rotation angles ranging from -70 degrees to +70 degrees in 5 degrees increments along a single rotation axis. This form of microscopy (which we call 3D electron diffraction microscopy) does not require any reference waves, and can image the 3D structure of nanocrystals, as well as non-crystalline biological and materials science samples, with the resolution limited only by the quality of sample diffraction.

  10. Quantitative comparison of the void distribution in a. beta. '-phase Ni-Al-In alloy using x-ray small-angle scattering and transmission-electron microscopy. [Ni-51. 2 at. % Al-2. 6 at. % In

    SciTech Connect

    Epperson, J.E.; Loomis, B.A.; Lin, J.S.

    1981-11-01

    Small-angle scattering is a rather mature discipline which can yield valuable information on the size, amount, and distribution of inhomogeneities encountered in materials-science research. Methods have been publisheed which permit one to extend the standard analysis of data from a small-angle-scattering experiment to include determination of the distribution of particle sizes. This extended analysis has been carried out for voids in a ..beta..'-phase Ni-Al-In alloy, and, in order to assess the reliability of the procedure, the identical void distribution as been characterized by transmission-electron microscopy. A quantitative comparison is made of the results from thses two independent experiments, and the general performance of the Brill-Schmidt method for particle-size determinations is discussed. 6 figures, 1 table.

  11. Fast electron microscopy via compressive sensing

    SciTech Connect

    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.

  12. Quantitative chemical imaging with multiplex stimulated Raman scattering microscopy.

    PubMed

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

    2012-02-29

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

  13. 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.

  14. The future of electron microscopy

    SciTech Connect

    Zhu, Yimei; Durr, Hermann

    2015-04-01

    Seeing is believing. So goes the old adage and seen evidence is undoubtedly satisfying because it can be interpreted easily, though not always correctly. For centuries, humans have developed such instruments as telescopes that observe the heavens and microscopes that reveal bacteria and viruses. The 2014 Nobel Prize in Chemistry was awarded to Eric Betzig, Stefan Hell, and William Moerner for their foundational work on superresolution fluorescence microscopy in which they overcame the Abbe diffraction limit for the resolving power of conventional light microscopes. (See Physics Today, December 2014, page 18.) That breakthrough enabled discoveries in biological research and testifies to the importance of modern microscopy.

  15. The future of electron microscopy

    DOE PAGESBeta

    Zhu, Yimei; Durr, Hermann

    2015-04-01

    Seeing is believing. So goes the old adage and seen evidence is undoubtedly satisfying because it can be interpreted easily, though not always correctly. For centuries, humans have developed such instruments as telescopes that observe the heavens and microscopes that reveal bacteria and viruses. The 2014 Nobel Prize in Chemistry was awarded to Eric Betzig, Stefan Hell, and William Moerner for their foundational work on superresolution fluorescence microscopy in which they overcame the Abbe diffraction limit for the resolving power of conventional light microscopes. (See Physics Today, December 2014, page 18.) That breakthrough enabled discoveries in biological research and testifiesmore »to the importance of modern microscopy.« less

  16. Spin-polarized scanning electron microscopy.

    PubMed

    Koike, Kazuyuki

    2013-02-01

    Spin-polarized scanning electron microscopy (spin-SEM) is a magnetic domain observation method. In spin-SEM, polarization of secondary electrons emitted from a sample in a scanning electron microscope is detected by a spin detector and used as a signal for forming an image. The characteristics of spin-SEM are detection of all three magnetization vector components, which leads to the detection of the magnetization vector direction, high spatial resolution of around 3 nm and applicability to samples with rough or even 3D surfaces. Spin-SEM combined with other imaging methods using an electron probe beam such as scanning Auger electron microscopy for imaging element distribution and electron backscattering diffraction microscopy for imaging crystal direction distribution provides additional information that is important to study the magnetism. Spin-SEM with these excellent characteristics has a broad range of applications from basic research to applied research and developments in various industries. PMID:23325928

  17. Fluorescence-integrated transmission electron microscopy images: integrating fluorescence microscopy with transmission electron microscopy.

    PubMed

    Sims, Paul A; Hardin, Jeff D

    2007-01-01

    This chapter describes high-pressure freezing (HPF) techniques for correlative light and electron microscopy on the same sample. Laser scanning confocal microscopy (LSCM) is exploited for its ability to collect fluorescent, as well as transmitted and back scattered light (BSL) images at the same time. Fluorescent information from a whole mount (preembedding) or from thin sections (post-embedding) can be displayed as a color overlay on transmission electron microscopy (TEM) images. Fluorescence-integrated TEM (F-TEM) images provide a fluorescent perspective to TEM images. The pre-embedding method uses a thin two-part agarose pad to immobilize live Caenorhabditis elegans embryos for LSCM, HPF, and TEM. Pre-embedding F-TEM images display fluorescent information collected from a whole mount of live embryos onto all thin sections collected from that sample. In contrast, the postembedding method uses HPF and freeze substitution with 1% paraformaldehyde in 95% ethanol followed by low-temperature embedding in methacrylate resin. This procedure preserves the structure and function of green fluorescent protein (GFP) as determined by immunogold labeling of GFP, when compared with GFP expression, both demonstrated in the same thin section. PMID:17656756

  18. Postdoctoral Research Associate in Aberration Corrected Electron Microscopy

    E-print Network

    MacIver, Malcolm A.

    Postdoctoral Research Associate in Aberration Corrected Electron Microscopy Position Available a Postdoctoral Research Associate in Aberration Corrected Scanning / Transmission Electron Microscopy to develop in the use of Transmission Electron Microscopy including HRTEM, HAADF-STEM, and EELS/EDS spectroscopy

  19. 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 in materials design and system analysis. High-resolution transmission electron microscopy (HRTEM) is one

  20. Carving: Scalable Interactive Segmentation of Neural Volume Electron Microscopy Images

    E-print Network

    Hamprecht, Fred A.

    Carving: Scalable Interactive Segmentation of Neural Volume Electron Microscopy Images C. N electron microscopy images. We propose a supervoxel-based en- ergy function with a novel background prior available. Keywords: electron microscopy, seeded segmentation, interactive seg- mentation, graph cut

  1. Transmission Electron Microscopy at Palaiseau Orsay Saclay: TEMPOS

    E-print Network

    Transmission Electron Microscopy at Palaiseau Orsay Saclay: TEMPOS 1 #12;Transmission Electron Microscopy at Palaiseau Orsay Saclay: TEMPOS NANOTEM (LPN) Equipement de) NANOMAX (X) 1 #12;Transmission Electron Microscopy at Palaiseau Orsay Saclay: TEMPOS

  2. 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.

  3. 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...

  4. 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.

  5. Quantitative microscopy of mole rat eosinophil granule morphology.

    PubMed

    Amihai, Dina; Meilijson, Isaac; Terkel, Joseph; Hammel, Ilan

    2015-10-01

    Mole rat bone marrow cells and peritoneal eosinophils are used to study granule morphological maturation by quantitative microscopy. The bulk eosinophil granule content is pre-stored in unique granular structures known as crystalloid or secondary granules. Mole rat eosinophil granules exhibit the basic structure of an electron-dense crystalloid core surrounded by a lighter, homogeneous matrix. Morphometric analysis demonstrated that bone marrow-derived eosinophil sphere-like granules display a periodic, multimodal granule volume distribution. In contrast, peritoneal eosinophils display cigar-shaped granules, whose crystalloid cores are more variable in size and shape as compared to bone marrow eosinophil granules. Using a morphometric approach, we deduced that the basic granule volume quantum is similar in both cases, suggesting that the sphere-like young eosinophil granules turn into dense ellipsoidal ones by intragranular processes in which both volume and membrane surface are conserved. Crystalloid granule mediators are known to be widely associated with allergic inflammatory events, which may damage the host tissue following secretion to the extracellular environment. Based on mathematical modeling, we suggest that this deviation from sphere-like to ellipsoidal shape reflects an adaptive response of the mole rat to its unique solitary life. PMID:25971930

  6. Low voltage transmission electron microscopy of graphene.

    PubMed

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

    2015-02-01

    The initial isolation of graphene in 2004 spawned massive interest in this two-dimensional pure sp(2) carbon structure due to its incredible electrical, optical, mechanical, and thermal effects. This in turn led to the rapid development of various characterization tools for graphene. Examples include Raman spectroscopy and scanning tunneling microscopy. However, the one tool with the greatest prowess for characterizing and studying graphene is the transmission electron microscope. State-of-the-art (scanning) transmission electron microscopes enable one to image graphene with atomic resolution, and also to conduct various other characterizations simultaneously. The advent of aberration correctors was timely in that it allowed transmission electron microscopes to operate with reduced acceleration voltages, so that damage to graphene is avoided while still providing atomic resolution. In this comprehensive review, a brief introduction is provided to the technical aspects of transmission electron microscopes relevant to graphene. The reader is then introduced to different specimen preparation techniques for graphene. The different characterization approaches in both transmission electron microscopy and scanning transmission electron microscopy are then discussed, along with the different aspects of electron diffraction and electron energy loss spectroscopy. The use of graphene for other electron microscopy approaches such as in-situ investigations is also presented. PMID:25408379

  7. 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.

  8. 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.

  9. Electron Microscopy of Natural and Epitaxial Diamond

    NASA Technical Reports Server (NTRS)

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

    1993-01-01

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

  10. Low-pass secondary electron detector for outlens scanning electron microscopy

    NASA Astrophysics Data System (ADS)

    Sekiguchi, Takashi; Iwai, Hideo

    2015-08-01

    A low-pass secondary electron detector has been invented for outlens scanning electron microscopy. This detector is composed of a bias grid above and an electron detector below the specimen. The upward low-energy electrons emitted from the specimen are reflected downward by the bias grid and reach the secondary electron detector. The high-energy electrons penetrate the grid and are not detected. This detector has an advantage of quantitative analysis because the secondary electron trajectories are easily traced with simple parabolic motion. The energy-filtered images of the GaN/Si sample are obtained using this detector.

  11. Advanced Electron Microscopy in Materials Physics

    SciTech Connect

    Zhu, Y.; Jarausch, K.

    2009-06-01

    Aberration correction has opened a new frontier in electron microscopy by overcoming the limitations of conventional round lenses, providing sub-angstrom-sized probes and extending information limits. The imaging and analytical performance of these corrector-equipped microscopes affords an unprecedented opportunity to study structure-property relationships of matter at the atomic scale. This new generation of microscopes is able to retrieve high-quality structural information comparable to neutron and synchrotron x-ray experiments, but with local atomic resolution. These advances in instrumentation are accelerating the research and development of various functional materials ranging from those for energy generation, conversion, transportation and storage to those for catalysis and nano-device applications. The dramatic improvements in electron-beam illumination and detection also present a host of new challenges for the interpretation and optimization of experiments. During 7-9 November 2007, a workshop, entitled 'Aberration Corrected Electron Microscopy in Material Physics', was convened at the Center for Functional Nanomaterials, Brookhaven National Laboratories (BNL) to address these opportunities and challenges. The workshop was co-sponsored by Hitachi High Technologies, a leader in electron microscopy instrumentation, and BNL's Institute of Advanced Electron Microscopy, a leader in materials physics research using electron microscopy. The workshop featured presentations by internationally prominent scientists working at the frontiers of electron microscopy, both on developing instrumentation and applying it in materials physics. The meeting, structured to stimulate scientific exchanges and explore new capabilities, brought together {approx}100 people from over 10 countries. This special issue complies many of the advances in instrument performance and materials physics reported by the invited speakers and attendees at the workshop.

  12. Self-consistent absorption correction for quantitative energy- dispersive X-ray spectroscopy of InGaN layers in analytical transmission electron microscopy

    NASA Astrophysics Data System (ADS)

    Walther, T.; Wang, X.

    2015-10-01

    A new method of absorption correction for energy-dispersive X-ray spectroscopy in a transmission electron microscope is tested on InGaN samples. We simulate the effective k-factor for the In L line with respect to Ga L or Ga K and plot this as a function of the Ga K/L intensity ratio, which can be directly measured from experimental spectra. This basically performs an internal self-consistency check in the quantification using differently absorbed X-ray lines, which is in principle equivalent to an absorption correction as a function of specimen thickness but has the practical advantage that neither specimen thickness nor density or mass-thickness of the specimens need actually be measured.

  13. High-speed quantitative interferometric microscopy based phase imaging cytometer

    NASA Astrophysics Data System (ADS)

    Xue, Liang; Sun, Nan; Yan, Keding; Liu, Fei; Wang, Shouyu

    2014-11-01

    The paper proposed a simple large scale bio-sample phase detecting equipment called gravity driven phase detecting cytometer, which is based on quantitative interferometric microscopy to realize flowing red blood cells phase distribution detection. The method has advantages on high throughput phase detecting and statistical analysis with high detecting speed and in real-time. The statistical characteristics of red blood cells are useful for biological analysis and disease detection. We believe this method is shedding more light on quantitatively measurement of the phase distribution of bio-samples.

  14. Quantitative sectioning and noise analysis for structured illumination microscopy

    PubMed Central

    Hagen, Nathan; Gao, Liang; Tkaczyk, Tomasz S.

    2011-01-01

    Structured illumination (SI) has long been regarded as a nonquantitative technique for obtaining sectioned microscopic images. Its lack of quantitative results has restricted the use of SI sectioning to qualitative imaging experiments, and has also limited researchers’ ability to compare SI against competing sectioning methods such as confocal microscopy. We show how to modify the standard SI sectioning algorithm to make the technique quantitative, and provide formulas for calculating the noise in the sectioned images. The results indicate that, for an illumination source providing the same spatially-integrated photon flux at the object plane, and for the same effective slice thicknesses, SI sectioning can provide higher SNR images than confocal microscopy for an equivalent setup when the modulation contrast exceeds about 0.09. PMID:22274364

  15. Electron microscopy of Paramecium (Ciliata).

    PubMed

    Hausmann, Klaus; Allen, Richard D

    2010-01-01

    Paramecium may be the best known single-celled organism in existence (Hausmann et al., 2003). Today its image often appears on television programs where the producers use it to illustrate a stereotypic microorganism, be it pathogenic or nonpathogenic, prokaryotic or eukaryotic. Paramecium was probably one of the first single-celled organisms observed with a light microscope by the Dutch cloth vendor and amateur lens maker Antoni van Leuwenhoek (1632-1723) (Dobell, 1932), and it is still being investigated in the 21st century in the days of the modern electron microscopes. PMID:20869522

  16. Transmission electron microscopy of composites

    NASA Technical Reports Server (NTRS)

    Pirouz, P.; Farmer, S. C.; Ernst, F.; Chung, J.

    1988-01-01

    Since interphase-interfaces are often both the structurally weakest and chemically least stable regions of a composite material, they are critical determinants of such macrostructural characteristics as tensile strength and fracture toughness. Attention is presently given to the use of TEM for the study of interfaces between dissimilar materials; electron-diffraction, analytical, and high-resolution forms of TEM are employed, for the cases of both structural and semiconductor composites. The materials studied are SiC/Si, GaP/Si, and SiC fiber- and whisker-reinforced Si3N4.

  17. Electron Microscopy of the Cell

    PubMed Central

    Leeson, T. S.

    1965-01-01

    The use of the electron microscope has added much to our knowledge of the cell. The fine structure of the component parts of the nucleus and the cytoplasm is described, and their functions are indicated. The nature and structural modifications of the plasma membrane are illustrated with particular reference to function. To illustrate the interrelationships of the nucleus and cytoplasm, the theory of protein secretion is discussed, the secretion of a particular protein or polypeptide being determined by a particular nucleotide sequence in the desoxyribonucleic acid of a chromosome, that is, by a gene. This information is transferred from nucleus to cytoplasm. It is in the cytoplasm that the majority of the work is performed while the nucleus directs the work of the cell. ImagesFig. 2Fig. 3Fig. 4Fig. 5Fig. 6Fig. 7Fig. 8Fig. 9Fig. 10Fig. 11Fig. 12Fig. 13Fig. 14Fig. 15Fig. 16Fig. 17Fig. 18Fig. 19Fig. 20Fig. 21Fig. 22Fig. 23Fig. 24Fig. 25Fig. 26 PMID:5829410

  18. 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.

  19. Electron Microscopy: (Adv. Mater. 38/2015).

    PubMed

    2015-10-01

    The diversity of advanced electron microscopy tools and techniques at the Molecular Foundry enables researchers to probe a wide range of materials and their properties, including atomic defects in two dimensional materials, the chirality of domain walls in magnetic films, and functional behavior of single atoms. PMID:26448604

  20. 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

    Cat . Thom . Egg 1038/ . Egge . Gore ogr., B iang, D illha zalezarkable versatility of modern electron microscopy, cou- he increase in computational power and sophisticated ethods, has led to the growth of multi-dimensional icroscopy (MDEM). MDEM offers a way...

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

    E-print Network

    Fua, Pascal

    Flash 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 neuroscience has greatly benefited from Scanning Electron Microscope (SEM) technology. With its ability

  2. 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 ...

  3. Single beam Fourier transform digital holographic quantitative phase microscopy

    NASA Astrophysics Data System (ADS)

    Anand, A.; Faridian, A.; Chhaniwal, V. K.; Mahajan, S.; Trivedi, V.; Dubey, S. K.; Pedrini, G.; Osten, W.; Javidi, B.

    2014-03-01

    Quantitative phase contrast microscopy reveals thickness or height information of a biological or technical micro-object under investigation. The information obtained from this process provides a means to study their dynamics. Digital holographic (DH) microscopy is one of the most used, state of the art single-shot quantitative techniques for three dimensional imaging of living cells. Conventional off axis DH microscopy directly provides phase contrast images of the objects. However, this process requires two separate beams and their ratio adjustment for high contrast interference fringes. Also the use of two separate beams may make the system more vulnerable to vibrations. Single beam techniques can overcome these hurdles while remaining compact as well. Here, we describe the development of a single beam DH microscope providing whole field imaging of micro-objects. A hologram of the magnified object projected on to a diffuser co-located with a pinhole is recorded with the use of a commercially available diode laser and an arrayed sensor. A Fourier transform of the recorded hologram directly yields the complex amplitude at the image plane. The method proposed was investigated using various phase objects. It was also used to image the dynamics of human red blood cells in which sub-micrometer level thickness variation were measurable.

  4. Single beam Fourier transform digital holographic quantitative phase microscopy

    SciTech Connect

    Anand, A. Chhaniwal, V. K.; Mahajan, S.; Trivedi, V.; Faridian, A.; Pedrini, G.; Osten, W.; Dubey, S. K.; Javidi, B.

    2014-03-10

    Quantitative phase contrast microscopy reveals thickness or height information of a biological or technical micro-object under investigation. The information obtained from this process provides a means to study their dynamics. Digital holographic (DH) microscopy is one of the most used, state of the art single-shot quantitative techniques for three dimensional imaging of living cells. Conventional off axis DH microscopy directly provides phase contrast images of the objects. However, this process requires two separate beams and their ratio adjustment for high contrast interference fringes. Also the use of two separate beams may make the system more vulnerable to vibrations. Single beam techniques can overcome these hurdles while remaining compact as well. Here, we describe the development of a single beam DH microscope providing whole field imaging of micro-objects. A hologram of the magnified object projected on to a diffuser co-located with a pinhole is recorded with the use of a commercially available diode laser and an arrayed sensor. A Fourier transform of the recorded hologram directly yields the complex amplitude at the image plane. The method proposed was investigated using various phase objects. It was also used to image the dynamics of human red blood cells in which sub-micrometer level thickness variation were measurable.

  5. Mudrocks examined by backscattered electron microscopy

    NASA Technical Reports Server (NTRS)

    Pye, K.; Krinsley, D.

    1983-01-01

    A method of studying mudrocks is developed using backscattered electrons (BSE) in scanning electron microscopy. Commercially available detectors are utilized to mix the BSE and secondary electron signals in order to obtain the optimum image for a particular material. Thin sections or polished rock chip surfaces are examined with BSE which provides both the atomic number contrast and topographic contrast. This technique provides very detailed information about the form and composition of individual grains in the mudrock thin sections and can be used in studies of the source, mode of deposition, diagenesis, and tectonic deformational history of mudrocks.

  6. Quantitative X-ray Differential Interference Contrast Microscopy

    NASA Astrophysics Data System (ADS)

    Nakamura, Takashi

    Full-field soft x-ray microscopes are widely used in many fields of sciences. Advances in nanofabrication technology enabled short wavelength focusing elements with significantly improved spatial resolution. In the soft x-ray spectral region, samples as small as 12 nm can be resolved using micro zone-plates as the objective lens. In addition to conventional x-ray microscopy in which x-ray absorption difference provides the image contrast, phase contrast mechanisms such as differential phase contrast (DIC) and Zernike phase contrast have also been demonstrated These phase contrast imaging mechanisms are especially attractive at the x-ray wavelengths where phase contrast of most materials is typically 10 times stronger than the absorption contrast. With recent progresses in plasma-based x- ray sources and increasing accessibility to synchrotron user facilities, x-ray microscopes are quickly becoming standard measurement equipment in the laboratory. To further the usefulness of x-ray DIC microscopy this thesis explicitly addresses three known issues with this imaging modality by introducing new techniques and devices First, as opposed to its visible-light counterpart, no quantitative phase imaging technique exists for x-ray DIC microscopy. To address this issue, two nanoscale x-ray quantitative phase imaging techniques, using exclusive OR (XOR) patterns and zone-plate doublets, respectively, are proposed. Unlike existing x-ray quantitative phase imaging techniques such as Talbot interferometry and ptychography, no dedicated experimental setups or stringent illumination coherence are needed for quantitative phase retrieval. Second, to the best of our knowledge, no quantitative performance characterization of DIC microscopy exists to date. Therefore the imaging system's response to sample's spatial frequency is not known In order to gain in-depth understanding of this imaging modality, performance of x-ray DIC microscopy is quantified using modulation transfer function. A new illumination apparatus required for the transfer function analysis under partially coherent illumination is also proposed. Such a characterization is essential for a proper selection of DIC optics for various transparent samples under study. Finally, optical elements used for x-ray DIC microscopy are highly absorptive and high brilliance x-ray sources such as synchrotrons are generally needed for image contrast. To extend the use of x-ray DIC microscopy to a wider variety of applications, a high efficiency large numerical aperture optical element consisting of high reflective Bragg reflectors is proposed. Using Bragg reflectors, which have 70% ˜99% reflectivity at extreme ultraviolet and soft x-rays for all angles of glancing incidence, the first order focusing efficiency is expected to increase by ˜ 8 times compared to that of a typical Fresnel zone-plate. This thesis contributes to current nanoscale x-ray phase contrast imaging research and provides new insights for biological, material, and magnetic sciences

  7. Environmental scanning electron microscopy in cell biology.

    PubMed

    McGregor, J E; Staniewicz, L T L; Guthrie Neé Kirk, S E; Donald, A M

    2013-01-01

    Environmental scanning electron microscopy (ESEM) (1) is an imaging technique which allows hydrated, insulating samples to be imaged under an electron beam. The resolution afforded by this technique is higher than conventional optical microscopy but lower than conventional scanning electron microscopy (CSEM). The major advantage of the technique is the minimal sample preparation needed, making ESEM quick to use and the images less susceptible to the artifacts that the extensive sample preparation usually required for CSEM may introduce. Careful manipulation of both the humidity in the microscope chamber and the beam energy are nevertheless essential to prevent dehydration and beam damage artifacts. In some circumstances it is possible to image live cells in the ESEM (2).In the following sections we introduce the fundamental principles of ESEM imaging before presenting imaging protocols for plant epidermis, mammalian cells, and bacteria. In the first two cases samples are imaged using the secondary electron (topographic) signal, whereas a transmission technique is employed to image bacteria. PMID:23027020

  8. Standardless Atom Counting in Scanning Transmission Electron Microscopy

    E-print Network

    Melbourne, University of

    Standardless Atom Counting in Scanning Transmission Electron Microscopy James M. LeBeau,*, Scott D electron microscopy allows for quantification of the number and location of all atoms in a three transmission electron microscope. KEYWORDS Scanning transmission electron microscopy (STEM), gold, nanoscale

  9. Reflection Electron Microscopy and Spectroscopy for Surface Analysis

    E-print Network

    Wang, Zhong L.

    1 Reflection Electron Microscopy and Spectroscopy for Surface Analysis by Zhong Lin Wang known as high-resolution analytical electron microscopy, which is becoming an indispensable technique. This book is about the reflection high-energy electron diffraction (RHEED), reflection electron microscopy

  10. 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

  11. 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

  12. Scanning electron microscopy of superficial white onychomycosis*

    PubMed Central

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

    2015-01-01

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

  13. Scanning electron microscopy of superficial white onychomycosis.

    PubMed

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

    2015-10-01

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

  14. 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.

  15. Electron Microscopy Study of Tin Whisker Growth

    SciTech Connect

    Norton, Murray G.; Lebret, Joel

    2003-03-30

    The growth of tin whiskers formed on sputtered tin layers deposited on brass was studied using electron microscopy. The occurrence of whiskers appeared to be largely independent of the macroscopic stress state in the film; rather it was microscopic compressive stresses arising from the formation of an intermetallic phase that appeared to be the necessary precursor. Whisker morphology was a result of whether nucleation had occurred on single grains or on multiple grains. In the latter case, the whiskers had a fluted or striated surface. The formation of whiskers on electron transparent samples was demonstrated. These samples showed the whiskers were monocrystalline and defect free, and that the growth direction could be determined.

  16. Quantitative electrostatic force microscopy with sharp silicon tips.

    PubMed

    Fumagalli, L; Edwards, M A; Gomila, G

    2014-12-12

    Electrostatic force microscopy (EFM) probes are typically coated in either metal (radius ? 30 nm) or highly-doped diamond (radius ? 100 nm). Highly-doped silicon probes, which offer a sharpened and stable tip apex (radius ? 1-10 nm) and are usually used only in standard atomic force microscopy, have been recently shown to allow enhanced lateral resolution in quantitative EFM and its application for dielectric constant measurement. Here we present the theoretical modelling required to quantitatively interpret the electrostatic force between these sharpened tips and samples. In contrast to a sphere-capped cone geometry used to describe metal/diamond-coated tips, modelling a sharpened silicon tip requires a geometry comprised of a cone with two different angles. Theoretical results are supported by experimental measurements of metallic substrates and ?10 nm radius dielectric nanoparticles. This work is equally applicable to EFM and other electrical scanned probe techniques, where it allows quantifying electrical properties of nanomaterials and 3D nano-objects with higher resolution. PMID:25407683

  17. Quantitative electrostatic force microscopy with sharp silicon tips

    NASA Astrophysics Data System (ADS)

    Fumagalli, L.; Edwards, M. A.; Gomila, G.

    2014-12-01

    Electrostatic force microscopy (EFM) probes are typically coated in either metal (radius ˜ 30 nm) or highly-doped diamond (radius ˜ 100 nm). Highly-doped silicon probes, which offer a sharpened and stable tip apex (radius ˜ 1-10 nm) and are usually used only in standard atomic force microscopy, have been recently shown to allow enhanced lateral resolution in quantitative EFM and its application for dielectric constant measurement. Here we present the theoretical modelling required to quantitatively interpret the electrostatic force between these sharpened tips and samples. In contrast to a sphere-capped cone geometry used to describe metal/diamond-coated tips, modelling a sharpened silicon tip requires a geometry comprised of a cone with two different angles. Theoretical results are supported by experimental measurements of metallic substrates and ˜10 nm radius dielectric nanoparticles. This work is equally applicable to EFM and other electrical scanned probe techniques, where it allows quantifying electrical properties of nanomaterials and 3D nano-objects with higher resolution.

  18. 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

  19. Correlative light and electron microscopy using cathodoluminescence from nanoparticles

    E-print Network

    Walsworth, Ronald L.

    Correlative light and electron microscopy using cathodoluminescence from nanoparticles 02138 Figure S1: Co-localization of secondary electron (SE) and cathodoluminescence (CL) images of Lu their utility as coloured markers for correlative microscopy. Scale bars are 200 nm. #12;

  20. 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

  1. Spatial Resolution and Information Transfer in Scanning Transmission Electron Microscopy

    E-print Network

    Pennycook, Steve

    Spatial Resolution and Information Transfer in Scanning Transmission Electron Microscopy Yiping of scanning transmission electron microscopy, it is shown that the channeling effect does not have a direct microscopy, especially the break- through brought by the practical correction of electron optical aberrations

  2. Electron Microscopy DOI: 10.1002/anie.200604811

    E-print Network

    Dunin-Borkowski, Rafal E.

    Electron Microscopy DOI: 10.1002/anie.200604811 Aberration-Corrected Imaging of Active Sites of ammonia synthesis in a Ru-catalyzed reaction.[1] High-resolution trans- mission electron microscopy (HRTEM.[3] Here, we show that spherical-aberration-corrected trans- mission electron microscopy (TEM) can

  3. Recent progress in chromatic aberration corrected transmission electron microscopy

    E-print Network

    Dunin-Borkowski, Rafal E.

    Recent progress in chromatic aberration corrected transmission electron microscopy L. Houben, M. Luysberg and R.E. Dunin-Borkowski 1 Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons (ER of thick specimens. For energy- filtered transmission electron microscopy (EFTEM), chromatic aberration

  4. Three-Dimensional Scanning Transmission Electron Microscopy of Biological Specimens

    E-print Network

    Pennycook, Steve

    Three-Dimensional Scanning Transmission Electron Microscopy of Biological Specimens Niels de Jonge is comparable to that achieved by tilt-series transmission electron microscopy. However, the focal-series method in the deconvolved dataset. Key words: three-dimensional electron microscopy, aberration-corrected STEM, biological

  5. Visualization of Nucleosomes in Thin Sections by Stereo Electron Microscopy

    E-print Network

    Olins, Ada L.

    Visualization of Nucleosomes in Thin Sections by Stereo Electron Microscopy ADA L. OLINS, DONALD E argued that stereo electron microscopy (stereo EM) of 25-nm chro- matin fibers reveals a substructure nucleosomes to procedures used for preparing thin sections for electron microscopy. Surprisingly, however

  6. Transmission Electron Microscopy Biology Course Numbers: 5510/5511

    E-print Network

    Chalcraft, David R.

    1 Transmission Electron Microscopy Biology Course Numbers: 5510/5511 Spring Credit 4 (2) Thursday: 6-8:50 PM TEXTS: (1) Electron Microscopy, Second edition. 2008. John J. Bozzola of the poster will be 42" x 33.5". Lecture/Laboratory Topics: Topic: Text Chapter 1. Electron Microscopy History

  7. Combining electron microscopy and comparative protein structure modeling

    E-print Network

    Sali, Andrej

    Combining electron microscopy and comparative protein structure modeling Maya Topf and Andrej Sali Recently, advances have been made in methods and applications that integrate electron microscopy density microscopy can benefit from comparative modeling through the fitting of comparative models into electron

  8. HVEM Grid: Experiences in Constructing an Electron Microscopy Grid

    E-print Network

    Yeom, Heon Young

    HVEM Grid: Experiences in Constructing an Electron Microscopy Grid Hyuck Han1 , Hyungsoo Jung1 National University, Seoul 151-742, Korea {hhyuck, jhs, yeom}@dcslab.snu.ac.kr 2 Electron Microscopy Team-located instrument, a High Voltage Electron Microscopy (HVEM). Our architecture is designed to materialize all

  9. Applications of a bilateral denoising filter in biological electron microscopy

    E-print Network

    Jiang, Wen

    Applications of a bilateral denoising filter in biological electron microscopy Wen Jiang,a Matthew of biological sample to the radiation damage, the low dose imaging conditions used for electron microscopy the effectiveness of a bilateral denoising filter in various biological electron microscopy applications

  10. Meeting Review Outcome of the First Electron Microscopy

    E-print Network

    Sali, Andrej

    Structure Meeting Review Outcome of the First Electron Microscopy Validation Task Force Meeting the inaugural meeting of the Electron Microscopy Validation Task Force organized by the Unified Data Resource 28 and 29, 2010. At the workshop, a group of scientists involved in collecting electron microscopy

  11. Ground Truth Estimation by Maximizing Topological Agreements in Electron Microscopy

    E-print Network

    Choe, Yoonsuck

    Ground Truth Estimation by Maximizing Topological Agreements in Electron Microscopy Data Huei are not suited for electron microscopy (EM) images because they typically do not take into account topological results. 1 Introduction Electron microscopy (EM) image segmentation is the first step toward the recon

  12. Electron Microscopy Image Segmentation with Graph Cuts Utilizing Estimated Symmetric

    E-print Network

    Choe, Yoonsuck

    Electron Microscopy Image Segmentation with Graph Cuts Utilizing Estimated Symmetric Three-Face Scanning Electron Microscopy (SBFSEM) [3] for example, pro- vide sufficient resolution to identify synaptic II, LNCS 6454, pp. 322­331, 2010. c Springer-Verlag Berlin Heidelberg 2010 #12;Electron Microscopy

  13. Mega-Dalton Biomolecular Motion Captured from Electron Microscopy Reconstructions

    E-print Network

    Wriggers, Willy

    Mega-Dalton Biomolecular Motion Captured from Electron Microscopy Reconstructions Pablo Chaco foundation for this analysis, we demonstrate here on experimental electron microscopy maps that vibrational flexibility of chaperonin CCT are extracted directly from single electron microscopy structures at 15­27 A

  14. Transmission Electron Microscopy S J Pennycook, Oak Ridge National Laboratory,

    E-print Network

    Pennycook, Steve

    Transmission Electron Microscopy S J Pennycook, Oak Ridge National Laboratory, Oak Ridge, TN, USA Published by Elsevier Ltd. Introduction The distinguishing feature of transmission electron microscopy (TEM.1­0.2 nm. Now electron microscopy is in the midst of a revolution. Thanks to the development of solid

  15. Scanning Electron Microscopy Biology Course Numbers: 5520/5521

    E-print Network

    Chalcraft, David R.

    1 Scanning Electron Microscopy Biology Course Numbers: 5520/5521 Spring Credit 4 (2) Thursday: 6-8:50 PM TEXTS: (1) Electron Microscopy, Second edition. 2008. John J. Bozzola of the poster will be 42" x 33.5". Lecture/Laboratory Topics: Topic: Text Chapter 1. Electron Microscopy History

  16. Serial Block-Face Scanning Electron Microscopy to Reconstruct

    E-print Network

    Born, Richard

    Serial Block-Face Scanning Electron Microscopy to Reconstruct Three-Dimensional Tissue of tissue prepared using techniques that are routine for transmission electron microscopy. Low- vacuum (20 providing a two-dimensional cross section through the tissue. Scanning electron microscopy (SEM) (Ardenne

  17. Optimization-Based Artifact Correction for Electron Microscopy Image Stacks

    E-print Network

    Abbeel, Pieter

    Optimization-Based Artifact Correction for Electron Microscopy Image Stacks Samaneh Azadi, Jeremy system, increasingly rely on large, high-resolution electron microscopy (EM) image volumes. However is available at http://rll.berkeley.edu/2014_ECCV_ EMISAC. Keywords: Denoising, Volume Electron Microscopy

  18. Development of a Nanoindenter for In Situ Transmission Electron Microscopy

    E-print Network

    Development of a Nanoindenter for In Situ Transmission Electron Microscopy Eric A. Stach,1 * Tony J.W. Morris, Jr.,3,4 A. Zettl,4,5 and Ulrich Dahmen1 1 National Center for Electron Microscopy, Charlottesville, VA 22903 Abstract: In situ transmission electron microscopy is an established experimental

  19. Macromolecular assembly structures by comparative modeling and electron microscopy

    E-print Network

    Sali, Andrej

    Macromolecular assembly structures by comparative modeling and electron microscopy Keren Lasker1: Methods in Molecular Biology Date: February 5, 2011 #12;Abstract Advances in electron microscopy allow in this process is fitting component structures into the electron microscopy-derived density map of their assembly

  20. Direct imaging of crystal structure and defects in metastable Ge{sub 2}Sb{sub 2}Te{sub 5} by quantitative aberration-corrected scanning transmission electron microscopy

    SciTech Connect

    Ross, Ulrich; Lotnyk, Andriy Thelander, Erik; Rauschenbach, Bernd

    2014-03-24

    Knowledge about the atomic structure and vacancy distribution in phase change materials is of foremost importance in order to understand the underlying mechanism of fast reversible phase transformation. In this Letter, by combining state-of-the-art aberration-corrected scanning transmission electron microscopy with image simulations, we are able to map the local atomic structure and composition of a textured metastable Ge{sub 2}Sb{sub 2}Te{sub 5} thin film deposited by pulsed laser deposition with excellent spatial resolution. The atomic-resolution scanning transmission electron microscopy investigations display the heterogeneous defect structure of the Ge{sub 2}Sb{sub 2}Te{sub 5} phase. The obtained results are discussed. Highly oriented Ge{sub 2}Sb{sub 2}Te{sub 5} thin films appear to be a promising approach for further atomic-resolution investigations of the phase change behavior of this material class.

  1. 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

  2. Determination of elemental distribution in green micro-algae using synchrotron radiation nano X-ray fluorescence (SR-nXRF) and electron microscopy techniques--subcellular localization and quantitative imaging of silver and cobalt uptake by Coccomyxa actinabiotis.

    PubMed

    Leonardo, T; Farhi, E; Boisson, A-M; Vial, J; Cloetens, P; Bohic, S; Rivasseau, C

    2014-02-01

    The newly discovered unicellular micro-alga Coccomyxa actinabiotis proves to be highly radio-tolerant and strongly concentrates radionuclides, as well as large amounts of toxic metals. This study helps in the understanding of the mechanisms involved in the accumulation and detoxification of silver and cobalt. Elemental distribution inside Coccomyxa actinabiotis cells was determined using synchrotron nano X-ray fluorescence spectroscopy at the ID22 nano fluorescence imaging beamline of the European Synchrotron Radiation Facility. The high resolution and high sensitivity of this technique enabled the assessment of elemental associations and exclusions in subcellular micro-algae compartments. A quantitative treatment of the scans was implemented to yield absolute concentrations of each endogenous and exogenous element with a spatial resolution of 100 nm and compared to the macroscopic content in cobalt and silver determined using inductively coupled plasma-mass spectrometry. The nano X-ray fluorescence imaging was complemented by transmission electron microscopy coupled to X-ray microanalysis (TEM-EDS), yielding differential silver distribution in the cell wall, cytosol, nucleus, chloroplast and mitochondria with unique resolution. The analysis of endogenous elements in control cells revealed that iron had a unique distribution; zinc, potassium, manganese, molybdenum, and phosphate had their maxima co-localized in the same area; and sulfur, copper and chlorine were almost homogeneously distributed among the whole cell. The subcellular distribution and quantification of cobalt and silver in micro-alga, assessed after controlled exposure to various concentrations, revealed that exogenous metals were mainly sequestered inside the cell rather than on mucilage or the cell wall, with preferential compartmentalization. Cobalt was homogeneously distributed outside of the chloroplast. Silver was localized in the cytosol at low concentration and in the whole cell excluding the nucleus at high concentration. Exposure to low concentrations of cobalt or silver did not alter the localization nor the concentration of endogenous elements within the cells. To our knowledge, this is the first report on element co-localization and segregation at the sub-cellular level in micro-algae by means of synchrotron nano X-ray fluorescence spectroscopy. PMID:24394991

  3. 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.

  4. 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.

  5. Digital holographic microscopy: a quantitative label-free microscopy technique for phenotypic screening.

    PubMed

    Rappaz, Benjamin; Breton, Billy; Shaffer, Etienne; Turcatti, Gerardo

    2014-01-01

    Digital Holographic Microscopy (DHM) is a label-free imaging technique allowing visualization of transparent cells with classical imaging cell culture plates. The quantitative DHM phase contrast image provided is related both to the intracellular refractive index and to cell thickness. DHM is able to distinguish cellular morphological changes on two representative cell lines (HeLa and H9c2) when treated with doxorubicin and chloroquine, two cytotoxic compounds yielding distinct phenotypes. We analyzed parameters linked to cell morphology and to the intracellular content in endpoint measurements and further investigated them with timelapse recording. The results obtained by DHM were compared with other optical label-free microscopy techniques, namely Phase Contrast, Differential Interference Contrast and Transport of Intensity Equation (reconstructed from three bright-field images). For comparative purposes, images were acquired in a common 96-well plate format on the different motorized microscopes. In contrast to the other microscopies assayed, images generated with DHM can be easily quantified using a simple automatized on-the-fly analysis method for discriminating the different phenotypes generated in each cell line. The DHM technology is suitable for the development of robust and unbiased image-based assays. PMID:24152227

  6. 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.

  7. "Electron microscopy in Life Sciences" Carmen Lpez-Iglesias

    E-print Network

    Ritort, Felix

    "Electron microscopy in Life Sciences" Carmen López-Iglesias #12;Electron Microscopy in Cellular discovers the electron as a charged particle. Then: experimentation period testing the deviation and concentration of an electron beam by means of electric and magnetic fields. ·1924 De Broglie hypothesis

  8. RESEARCH NEWS VOLUME 12 ELECTRON MICROSCOPY SPECIAL ISSUE 7

    E-print Network

    Espinosa, Horacio D.

    RESEARCH NEWS VOLUME 12 ­ ELECTRON MICROSCOPY SPECIAL ISSUE 7 A new diamond probe tip Microscopically wearing issues MICROSCOPY A biocompatible and biodegradable organic electronic device could change. Atomic force microscopy is one of the most powerful analytical techniques available to science. It can

  9. High pressure freezing, electron microscopy, and immuno-electron microscopy of Tetrahymena thermophila basal bodies.

    PubMed

    Meehl, Janet B; Giddings, Thomas H; Winey, Mark

    2009-01-01

    Preservation of Tetrahymena thermophila basal body ultrastructure for visualization by transmission electron microscopy is improved by a combination of high pressure freezing (HPF) and freeze substitution (FS). These methods also reliably retain the antigenicity of cellular proteins for immuno-electron microscopy, which enables the precise localization of green fluorescent protein (GFP)-tagged and native basal body proteins. The plastic-embedded samples generated by these methods take full advantage of higher resolution visualization techniques such as electron tomography. We describe protocols for cryofixation, FS, immunolabeling, and staining. Suggestions for trouble shooting and evaluation of specimen quality are discussed. In combination with identification and manipulation of a rapidly expanding list of basal body-associated gene products, these methods are being used to increase our understanding of basal body composition, assembly, and function. PMID:19768433

  10. 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

  11. Analyzing Tau Aggregation with Electron Microscopy.

    PubMed

    Huseby, Carol J; Kuret, Jeff

    2016-01-01

    Conversion of monomeric tau protein into filamentous aggregates is a defining event in the pathogenesis of Alzheimer's disease. To gain insight into disease pathogenesis, the mechanisms that trigger and mediate tau aggregation are under intense investigation. Characterization efforts have relied primarily on recombinant tau protein preparations and high-throughput solution-based detection methods such as thioflavin-dye fluorescence and laser-light-scattering spectroscopies. Transmission electron microscopy (TEM) is a static imaging tool that complements these approaches by detecting individual tau filaments at nanometer resolution. In doing so, it can provide unique insight into the quality, quantity, and composition of synthetic tau filament populations. Here we describe protocols for analysis of tau filament populations by TEM for purposes of dissecting aggregation mechanism. PMID:26453208

  12. Improved methods for high resolution electron microscopy

    SciTech Connect

    Taylor, J.R.

    1987-04-01

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

  13. Hexamethyldisilazane for scanning electron microscopy of Gastrotricha.

    PubMed

    Hochberg, R; Litvaitis, M K

    2000-01-01

    We evaluated treatment with hexamethyldisilazane (HMDS) as an alternative to critical-point drying (CPD) for preparing microscopic Gastrotricha for scanning electron microscopy (SEM). We prepared large marine (2 mm) and small freshwater (100 microm) gastrotrichs using HMDS as the primary dehydration solvent and compared the results to earlier investigations using CPD. The results of HMDS dehydration are similar to or better than CPD for resolution of two important taxonomic features: cuticular ornamentation and patterns of ciliation. The body wall of both sculpted (Lepidodermella) and smooth (Dolichodasys) gastrotrichs retained excellent morphology as did the delicate sensory and locomotory cilia. The only unfavorable result of HMDS dehydration was an occasional coagulation of gold residue when the solvent had not fully evaporated before sputter-coating. We consider HMDS an effective alternative for preparing of gastrotrichs for SEM because it saves time and expense compared to CPD. PMID:10810982

  14. Visualization of yeast cells by electron microscopy.

    PubMed

    Osumi, Masako

    2012-01-01

    In the 1970s, hydrocarbon or methanol utilizable yeasts were considered as a material for foods and ethanol production. During the course of studies into the physiology of yeasts, we found that these systems provide a suitable model for the biogenesis and ultrastructure research of microbodies (peroxisomes). Microbodies of hydrocarbon utilizing Candida tropicalis multiply profusely from the preexisting microbody. ? oxidation enzymes in the microbody were determined by means of immunoelectron microscopy. We examined the ultrastructure of Candida boidinii microbodies grown on methanol, and found a composite crystalloid of two enzymes, alcohol oxidase and catalase, by analyzing using the optical diffraction and filtering technique and computer simulation. We established methods for preparing the protoplasts of Schizosaccharomyces pombe and conditions for the complete regeneration of the cell wall. The dynamic process of cell wall formation was clarified through our study of the protoplasts, using an improved ultra high resolution (UHR) FESEM S-900 and an S-900LV. It was found that ?-1,3-glucan, ?-1,6-glucan and ?-1,3-glucan, as well as ?-galactomannan, are ingredients of the cell wall. The process of septum formation during cell division was examined after cryo-fixation by high pressure freezing (HPF). It was also found that ?-1,3- and ?-1,3-glucans were located in the invaginating nascent septum, and later, highly branched ?-1,6-glucan also appeared on the second septum. The micro-sampling method, using a focused ion beam (FIB), has been applied to our yeast cell wall research. A combination of FIB and scanning transmission electron microscopy is useful in constructing 3D images and analyzing the molecular architecture of cells, as well as for electron tomography of thick sections of biological specimens. PMID:23231852

  15. 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.

  16. Quantitative high dynamic range beam profiling for fluorescence microscopy

    SciTech Connect

    Mitchell, T. J. Saunter, C. D.; O’Nions, W.; Girkin, J. M.; Love, G. D.

    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.

  17. 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.

  18. Letters to ESEX High resolution transmission electron microscopy

    E-print Network

    Dorn, Ron

    Letters to ESEX High resolution transmission electron microscopy evaluation of silica glaze reveals electron microscopy of a rock coating from the Ashikule Basin, Tibetan Plateau, reveals the presence dispersive electron microprobe analyses of silica glaze reveals six general types (Dorn, 1998): Type 1

  19. Drift Correction for Scanning-Electron Microscopy Michael T. Snella

    E-print Network

    Goyal, Vivek K

    Drift Correction for Scanning-Electron Microscopy by Michael T. Snella Submitted to the Department Correction for Scanning-Electron Microscopy by Michael T. Snella Submitted to the Department of Electrical for the degree of Master of Engineering in Electrical Engineering and Computer Science Abstract Scanning electron

  20. Laboratory Design for High-Performance Electron Microscopy

    E-print Network

    Knowles, David William

    Laboratory Design for High-Performance Electron Microscopy Michael A. O'Keefe, John H. Turner Center for Electron Microscopy OÅM Laboratory at LBNL; the FEGTEM Facility at the University of Sheffield, ORNL, Oak Ridge, TN USA Introduction Since publication of the classic text on the electron microscope

  1. Quantitative imaging of living cells by deep ultraviolet microscopy

    E-print Network

    Zeskind, Benjamin J

    2006-01-01

    Developments in light microscopy over the past three centuries have opened new windows into cell structure and function, yet many questions remain unanswered by current imaging approaches. Deep ultraviolet microscopy ...

  2. Electron microscopy: cytology of cell fractions.

    PubMed

    NOVIKOFF, A B

    1956-11-16

    It should be evident from this brief account that electron microscopy of thin sections is an invaluable asset in the study of fractions isolated by differential centrifugation. I have tried to indicate how the integrity of particles, purity of fractions, and the existence of new particles can be established through its use. I have also suggested the desirability of a common terminology for all cytology -classic, electron-microscopic, and biochemical. Some have expressed the opinion that neutral terms such as alpha, beta, and gamma membranes (59) are more useful than ergastoplasm, Golgi apparatus, and so forth. As helpful as such neutral terms may be in describing intracellular structures, they do not appear to me to substitute for historically rooted cytological names. Note added in proof: Since this article went to press there has appeared an important article by G. E. Palade and P. Siekevitz (60). These authors consider that the vesicles without granules found in the microsome fraction were "probably derived from the smooth surfaced parts of the endoplasmic reticulum." The latter were found to be continuous with the granule-studded membranes; "the two varieties of profiles represent local differentiation within a common system." The authors confirm the finding of Rouiller (18) and Novikoff et al. (7) of the dense bodies adjacent to the bile canaliculi and describe their presence in the microsome fraction as a "minor component." PMID:13380407

  3. ELECTRON MICROSCOPY OF ORAL CELLS IN VITRO

    PubMed Central

    Kumegawa, M.; Cattoni, M.; Rose, George G.

    1968-01-01

    Two special areas involving membranous components in strain KB cells were studied by electron microscopy. The first area described is that of the subsurface regions of two apposing cells in which flattened cisternae (one cisternae in each subsurface region) with membranes spaced 110–230 A apart were found in a confrontation alignment. The long dimension of the profiles of these cisternae ranges from 0.5 to 2 µ. At these intercellular contact areas, each cisterna is closely applied to the adjacent plasma membrane; the intervening space is 60–100 A. We have named the cisternae in these roughly symmetrical areas of cell contact the subsurface confronting cisternae. Communications between these cisternae and those of the rough-surfaced endoplasmic reticulum also were observed. The second area described is that of the intracytoplasmic confronting cisternae. These cisternae were observed as oval or round images about 0.3–1.4 µ in diameter, each image being composed of a pair of concentrically arranged confronting cisternae with membranes spaced 200–400 A apart. The apposing membranes of the two confronting cisternae are electron opaque, smooth, and free of ribosomes, whereas the unapposed membranes are less dense, scalloped, and associated with ribosomes. The spacing between the two intracytoplasmic confronting cisternae is 70–110 A. PMID:4868888

  4. Aberration-corrected electron microscopy of nanoparticles and intermetallic compounds

    E-print Network

    Dunin-Borkowski, Rafal E.

    Aberration-corrected electron microscopy of nanoparticles and intermetallic compounds M. Heggen for applications in energy-related catalysis, as well as novel intermetallic compounds, will be presented

  5. Analytical electron microscopy in mineralogy; exsolved phases in pyroxenes

    USGS Publications Warehouse

    Nord, G.L., Jr.

    1982-01-01

    Analytical scanning transmission electron microscopy has been successfully used to characterize the structure and composition of lamellar exsolution products in pyroxenes. At operating voltages of 100 and 200 keV, microanalytical techniques of x-ray energy analysis, convergent-beam electron diffraction, and lattice imaging have been used to chemically and structurally characterize exsolution lamellae only a few unit cells wide. Quantitative X-ray energy analysis using ratios of peak intensities has been adopted for the U.S. Geological Survey AEM in order to study the compositions of exsolved phases and changes in compositional profiles as a function of time and temperature. The quantitative analysis procedure involves 1) removal of instrument-induced background, 2) reduction of contamination, and 3) measurement of correction factors obtained from a wide range of standard compositions. The peak-ratio technique requires that the specimen thickness at the point of analysis be thin enough to make absorption corrections unnecessary (i.e., to satisfy the "thin-foil criteria"). In pyroxenes, the calculated "maximum thicknesses" range from 130 to 1400 nm for the ratios Mg/Si, Fe/Si, and Ca/Si; these "maximum thicknesses" have been contoured in pyroxene composition space as a guide during analysis. Analytical spatial resolutions of 50-100 nm have been achieved in AEM at 200 keV from the composition-profile studies, and analytical reproducibility in AEM from homogeneous pyroxene standards is ?? 1.5 mol% endmember. ?? 1982.

  6. 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

    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.

  7. Quantitative Connection between Ensemble Thermodynamics and Single-Molecule Kinetics: A Case Study Using Cryogenic Electron Microscopy and Single-Molecule Fluorescence Resonance Energy Transfer Investigations of the Ribosome.

    PubMed

    Kinz-Thompson, Colin D; Sharma, Ajeet K; Frank, Joachim; Gonzalez, Ruben L; Chowdhury, Debashish

    2015-08-27

    At equilibrium, thermodynamic and kinetic information can be extracted from biomolecular energy landscapes by many techniques. However, while static, ensemble techniques yield thermodynamic data, often only dynamic, single-molecule techniques can yield the kinetic data that describe transition-state energy barriers. Here we present a generalized framework based upon dwell-time distributions that can be used to connect such static, ensemble techniques with dynamic, single-molecule techniques, and thus characterize energy landscapes to greater resolutions. We demonstrate the utility of this framework by applying it to cryogenic electron microscopy (cryo-EM) and single-molecule fluorescence resonance energy transfer (smFRET) studies of the bacterial ribosomal pre-translocation complex. Among other benefits, application of this framework to these data explains why two transient, intermediate conformations of the pre-translocation complex, which are observed in a cryo-EM study, may not be observed in several smFRET studies. PMID:25785884

  8. 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 ...

  9. Quantitative Electron-Excited X-Ray Microanalysis of Borides, Carbides, Nitrides, Oxides, and Fluorides with Scanning Electron Microscopy/Silicon Drift Detector Energy-Dispersive Spectrometry (SEM/SDD-EDS) and NIST DTSA-II.

    PubMed

    Newbury, Dale E; Ritchie, Nicholas W M

    2015-10-01

    A scanning electron microscope with a silicon drift detector energy-dispersive X-ray spectrometer (SEM/SDD-EDS) was used to analyze materials containing the low atomic number elements B, C, N, O, and F achieving a high degree of accuracy. Nearly all results fell well within an uncertainty envelope of ±5% relative (where relative uncertainty (%)=[(measured-ideal)/ideal]×100%). Quantification was performed with the standards-based "k-ratio" method with matrix corrections calculated based on the Pouchou and Pichoir expression for the ionization depth distribution function, as implemented in the NIST DTSA-II EDS software platform. The analytical strategy that was followed involved collection of high count (>2.5 million counts from 100 eV to the incident beam energy) spectra measured with a conservative input count rate that restricted the deadtime to ~10% to minimize coincidence effects. Standards employed included pure elements and simple compounds. A 10 keV beam was employed to excite the K- and L-shell X-rays of intermediate and high atomic number elements with excitation energies above 3 keV, e.g., the Fe K-family, while a 5 keV beam was used for analyses of elements with excitation energies below 3 keV, e.g., the Mo L-family. PMID:26365439

  10. Imaging Cytoskeleton Components by Electron Microscopy.

    PubMed

    Svitkina, Tatyana

    2016-01-01

    The cytoskeleton is a complex of detergent-insoluble components of the cytoplasm playing critical roles in cell motility, shape generation, and mechanical properties of a cell. Fibrillar polymers-actin filaments, microtubules, and intermediate filaments-are major constituents of the cytoskeleton, which constantly change their organization during cellular activities. The actin cytoskeleton is especially polymorphic, as actin filaments can form multiple higher order assemblies performing different functions. Structural information about cytoskeleton organization is critical for understanding its functions and mechanisms underlying various forms of cellular activity. Because of the nanometer-scale thickness of cytoskeletal fibers, electron microscopy (EM) is a key tool to determine the structure of the cytoskeleton.This article describes application of rotary shadowing (or metal replica) EM for visualization of the cytoskeleton. The procedure is applicable to thin cultured cells growing on glass coverslips and consists of detergent extraction of cells to expose their cytoskeleton, chemical fixation to provide stability, ethanol dehydration and critical point drying to preserve three-dimensionality, rotary shadowing with platinum to create contrast, and carbon coating to stabilize replicas. This technique provides easily interpretable three-dimensional images, in which individual cytoskeletal fibers are clearly resolved, and individual proteins can be identified by immunogold labeling. More importantly, replica EM is easily compatible with live cell imaging, so that one can correlate the dynamics of a cell or its components, e.g., expressed fluorescent proteins, with high resolution structural organization of the cytoskeleton in the same cell. PMID:26498781

  11. 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.

  12. 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

  13. Probing Structural and Electronic Dynamics with Ultrafast Electron Microscopy

    SciTech Connect

    Plemmons, DA; Suri, PK; Flannigan, DJ

    2015-05-12

    In this Perspective, we provide an overview,of the field of ultrafast electron microscopy (UEM). We begin by briefly discussing the emergence of methods for probing ultrafast structural dynamics and the information that can be obtained. Distinctions are drawn between the two main types a probes for femtosecond (fs) dynamics fast electrons and X-ray photons and emphasis is placed on hour the nature of charged particles is exploited in ultrafast electron-based' experiments:. Following this, we describe the versatility enabled by the ease with which electron trajectories and velocities can be manipulated with transmission electron microscopy (TEM): hardware configurations, and we emphasize how this is translated to the ability to measure scattering intensities in real, reciprocal, and energy space from presurveyed and selected rianoscale volumes. Owing to decades of ongoing research and development into TEM instrumentation combined with advances in specimen holder technology, comprehensive experiments can be conducted on a wide range of materials in various phases via in situ methods. Next, we describe the basic operating concepts, of UEM, and we emphasize that its development has led to extension of several of the formidable capabilities of TEM into the fs domain, dins increasing the accessible temporal parameter spade by several orders of magnitude. We then divide UEM studies into those conducted in real (imaging), reciprocal (diffraction), and energy (spectroscopy) spate. We begin each of these sections by providing a brief description of the basic operating principles and the types of information that can be gathered followed by descriptions of how these approaches are applied in UM, the type of specimen parameter space that can be probed, and an example of the types of dynamics that can be resolved. We conclude with an Outlook section, wherein we share our perspective on some future directions of the field pertaining to continued instrument development and application of the technique to solving seemingly intractable materials problems in addition to discovery-based research. Our goal with this Perspective is to bring the capabilities of TIEM to the-attention of materials scientists, chemists, physicists, and engineers in hopes that new,avenues of research emerge and to make clear the large parameter space that is opened by extending TEM, and the ability to readily manipulate electron trajectories and energies, into the ultrafast domain.

  14. Atomic-Resolution Electron Energy Loss Spectroscopy Imaging in Aberration Corrected Scanning Transmission Electron Microscopy

    E-print Network

    Pennycook, Steve

    Transmission Electron Microscopy L. J. Allen,1 S. D. Findlay,1 A. R. Lupini,2 M. P. Oxley,1 and S. J. Pennycook electron microscopy (STEM) images for single, isolated atoms is primarily determined by the width transmission electron microscopy (STEM), very high spatial resolution has been demonstrated [1­4]; impurity

  15. Simulation of Spatially Resolved Electron Energy Loss Near-Edge Structure for Scanning Transmission Electron Microscopy

    E-print Network

    Pennycook, Steve

    Electron Microscopy M. P. Prange,1,2,* M. P. Oxley,1,2, M. Varela,2 S. J. Pennycook,2,1 and S. T December 2012) Aberration-corrected scanning transmission electron microscopy yields probe Continuing advances in scanning transmission electron microscopy (STEM), including aberration correction

  16. Transmission Electron A state-of-the-art Electron Microscopy Laboratory is part of

    E-print Network

    Toledo, University of

    Transmission Electron Microscopy A state-of-the-art Electron Microscopy Laboratory is part of the Advanced Microscopy & Imaging Center. The EM facility is directed by Dr. William Gunning who specializes lab is equipped with two transmission electron microscopes, one being used for clinical diagnostic

  17. Characterization of Magnetic Nanoparticles Using Energy-Selected Transmission Electron Microscopy

    E-print Network

    Dunin-Borkowski, Rafal E.

    Characterization of Magnetic Nanoparticles Using Energy-Selected Transmission Electron Microscopy carbon spherical matrix. Key words: analytical electron microscopy, energy-filtered transmission electron microscopy, magnetic nanoparticles INTRODUCTION Transmission electron microscopes ~TEMs! equipped with in

  18. Structural characterisation of Ge/Si quantum dots: a study using different electron microscopy techniques

    E-print Network

    Dunin-Borkowski, Rafal E.

    Structural characterisation of Ge/Si quantum dots: a study using different electron microscopy by molecular beam epitaxy (MBE). Transmission electron microscopy (TEM) techniques, including diffraction-contrast imaging, high-resolution lattice imaging, scanning transmission electron microscopy (STEM), electron

  19. Computational methods for constructing protein structure models from 3D electron microscopy maps

    E-print Network

    Kihara, Daisuke

    Computational methods for constructing protein structure models from 3D electron microscopy maps online 21 June 2013 Keywords: Electron microscopy Structure fitting Macromolecular structure modeling. All rights reserved. 1. Introduction Electron density maps from cryo-electron microscopy (cryo

  20. Transmission Electron Microscopy of Itokawa Regolith Grains

    NASA Technical Reports Server (NTRS)

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

    2013-01-01

    Introduction: In a remarkable engineering achievement, the JAXA space agency successfully recovered the Hayabusa space-craft in June 2010, following a non-optimal encounter and sur-face sampling mission to asteroid 25143 Itokawa. These are the first direct samples ever obtained and returned from the surface of an asteroid. The Hayabusa samples thus present a special op-portunity to directly investigate the evolution of asteroidal sur-faces, from the development of the regolith to the study of the effects of space weathering. Here we report on our preliminary TEM measurements on two Itokawa samples. Methods: We were allocated particles RA-QD02-0125 and RA-QD02-0211. Both particles were embedded in low viscosity epoxy and thin sections were prepared using ultramicrotomy. High resolution images and electron diffraction data were ob-tained using a JEOL 2500SE 200 kV field-emission scanning-transmission electron microscope. Quantitative maps and anal-yses were obtained using a Thermo thin-window energy-dispersive x-ray (EDX) spectrometer. Results: Both particles are olivine-rich (Fo70) with µm-sized inclusions of FeS and have microstructurally complex rims. Par-ticle RA-QD02-0125 is rounded and has numerous sub-µm grains attached to its surface including FeS, albite, olivine, and rare melt droplets. Solar flare tracks have not been observed, but the particle is surrounded by a continuous 50 nm thick, stuctur-ally disordered rim that is compositionally similar to the core of the grain. One of the surface adhering grains is pyrrhotite show-ing a S-depleted rim (8-10 nm thick) with nanophase Fe metal grains (<5 nm) decorating the outermost surface. The pyrrhotite displays a complex superstructure in its core that is absent in the S-depleted rim. Particle RA-QD02-0211 contains solar flare particle tracks (2x109 cm-2) and shows a structurally disordered rim 100 nm thick. The track density corresponds to a surface exposure of 103-104 years based on the track production rate of [1]. The dis-ordered rim is nanocrystalline with minor amorphous material between crystalline domains. Quantitative element maps show the outermost 10 nm of the disordered rim is Si-rich. Discussion and Conclusions: Both particles record the ef-fects of space weathering processes on Itokawa. Noguchi et al. [2] proposed that the disordered rims they observed on Itokawa particles largely result from solar wind radiation damage and we arrive at a similar conclusion for the two particles we analyzed. The microstructure of the S-depleted layer on the pyrrhotite grain in RA-QD02-0125 is similar to that observed in troilite irradiated with 1018 4 kV He+ [3, 4]. Prolonged irradiation has also been shown to disorder pyrrhotite such that the superstructure reflec-tions are lost [5].

  1. The Application of Fluorescence Lifetime Imaging Microscopy to Quantitatively Map Mixing and Temperature in Microfluidic Systems 

    E-print Network

    Graham, Emmelyn M

    2008-01-01

    The technique of Fluorescence Lifetime Imaging Microscopy (FLIM) has been employed to quantitatively and spatially map the fluid composition and temperature within microfluidic systems. A molecular probe with a ...

  2. 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 ...

  3. Relationship between the v2PO4/amide III ratio assessed by Raman spectroscopy and the calcium content measured by quantitative backscattered electron microscopy in healthy human osteonal bone

    NASA Astrophysics Data System (ADS)

    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 ?) 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.

  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. Imaging without Fluorescence: Nonlinear Optical Microscopy for Quantitative Cellular Imaging

    E-print Network

    Huang, Yanyi

    applications with nonlinear microscopy techniques. We first offer an introductory tutorial on nonlinear optical of biological systems at the cellular level through bioinformatic analysis, computational approaches to bioimage, and extract statistics from populations of cells with single cell resolution. This tutorial can be thought

  6. CONFOCAL MICROSCOPY SYSTEM PERFORMANCE: FOUNDATIONS FOR MEASUREMENTS, QUANTITATION AND SPECTROSCOPY

    EPA Science Inventory

    The confocal laser-scanning microscopy (CLSM) has enormous potential in many biological fields. The goal of a CLSM is to acquire and quantify fluorescence and in some instruments acquire spectral characterization of the emitted signal. The accuracy of these measurements demands t...

  7. Electron Microscopy of Interactions Between Engineered Nanomaterials and Cells

    E-print Network

    Pala, Nezih

    T TEM Electron Microscopy of Interactions Between Engineered Nanomaterials and Cells Terahertz microwave and millimeter-wave devices into the THz range. The second one is the free-electron-based sources like free-electron lasers and backward wave oscillators (BWOs). The third is the utilization of optical

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

    SciTech Connect

    Bobrinetski, I. I.; Kukin, V. N.; Nevolin, V. K. Simunin, M. M.

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

    SciTech Connect

    Keutner, Christoph; von Bohlen, Alex; Berges, Ulf; Espeter, Philipp; Schneider, Claus M.; Westphal, Carsten

    2014-10-07

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

  10. Fossil Coccoliths in Limestone Examined by Electron Microscopy.

    PubMed

    Honjo, S; Fischer, A G

    1964-05-15

    Examination of polished and etched limestone surfaces (Jurassic from the Alps, Paleocene from Spain) by electron microscopy reveals coccoliths, in varying stages of preservation, in numbers of 100,000 to 1,000,000 per culbic millimeter. PMID:17733613

  11. In Situ Transmission Electron Microscopy Characterization of Nanomaterials 

    E-print Network

    Lee, Joon Hwan 1977-

    2012-11-27

    With the recent development of in situ transmission electron microscopy (TEM) characterization techniques, the real time study of property-structure correlations in nanomaterials becomes possible. This dissertation reports the direct observations...

  12. Transmission electron microscopy characterisation of 0-D nanomaterials

    NASA Astrophysics Data System (ADS)

    Turner, Stuart Matthew

    When materials are scaled down to the nanometre level, a change in physical behaviour is frequently observed. In so-called 0-D nanomaterials (nanoparticles), these unique nanoscale properties are most abundant and are usually linked to either a change in (electronic) structure of the material or to the dominating influence of the particle surface at the nanometre scale. In this doctoral work the nanoscale properties of several nanoparticle systems have been studied using advanced transmission electron microscopy (TEM). Every material that was studied required for its solution a unique approach and a host of transmission electron microscopy techniques. The title of this doctoral work can be freely translated as "retrieving quantitatively the maximal and most accurate chemical, structural and morphological information from nanoparticles by advanced transmission electron microscopy, to uncover and explain their unique properties". Chapter 1 gives a brief general introduction to the world of nanomaterials and nanotechnology in general and more specifically to 0-D nanomaterials (nanoparticles). The unique properties and potential applications of these materials are described. The production of 0-D nanomaterials is not covered in this chapter, as this is an extremely broad field to cover in only a few pages. Instead, the production method for each of the materials is left to the detailed chapters that follow. In Chapter 2 the main transmission electron microscopy techniques used to characterise the materials in the further chapters are described together with the microscopes used to perform these techniques and their parameters of operation. Again, the sample-specific setups are listed in the detailed chapters that follow. Chapter 3 covers all work carried out on luminescent detonation nanodiamond powder for drug delivery and bio-medical imaging applications. Specific attention is paid to the morphology, surface chemistry and nitrogen incorporation of detonation nanodiamond particles cleaned by novel routes, and the possibility of production of luminescent N-V centres within the diamond nanoparticles is studied. Chapter 4 deals with self-arranged Co nanoparticle arrays, so-called superlattices. By closely studying the oxidation behaviour of such arrays, a new intrinsic property has been discovered: enhanced stability against oxidation of self-arranged cobalt nanoparticles. This intriguing physical behaviour of arranged cobalt nanoparticles has never been observed before. Chapter 5 describes and discusses all results obtained from TEM investigation of hybrid nanoporous-nanoparticle materials for advanced catalysis applications: first, the possibilities of TEM for the characterisation of the metal MOF material family; and second, the example of Au ZIF. Finally, in Chapter 6, assisted spray-pyrolysis generated ZnO nanoparticles are studied. The ZnO nanomaterial produced by a novel assisted spray pyrolysis method is compared to conventionally spray pyrolysed ZnO nanomaterials. The influence of assisted spray pyrolysis production on the size, morphology and optical properties (UV blocking capabilities) of the ZnO nanoparticles is studied for the case of citric-acid assisted spray pyrolysis.

  13. Transmission electron microscopy of exsolution lamellae in ilmenite-hematite: Implications for "lamellar magnetism"

    E-print Network

    Dunin-Borkowski, Rafal E.

    Transmission electron microscopy of exsolution lamellae in ilmenite-hematite: Implications to the chemistry of either hematite or ilmenite Transmission electron microscopy (TEM) is powerful tool scale. Lorentz electron microscopy can be used to observe magnetic microstructure in minerals directly

  14. Transmission electron microscopy characterization of Zircaloy-4 and ZIRLOTM oxide layers

    E-print Network

    Motta, Arthur T.

    Transmission electron microscopy characterization of Zircaloy-4 and ZIRLOTM oxide layers Benoit de, and archived before and after the transition, are characterized using transmission electron microscopy improvement. Results obtained from transmission electron microscopy (TEM) samples archived just before

  15. Precise and unbiased estimation of astigmatism and defocus in transmission electron microscopy

    E-print Network

    van Vliet, Lucas J.

    Precise and unbiased estimation of astigmatism and defocus in transmission electron microscopy 2012 Accepted 4 March 2012 Available online 12 March 2012 Keywords: Transmission electron microscopy analysis in transmission electron microscopy (TEM), it is essential to account for the effects

  16. Quantitative WDS analysis using electron probe microanalyzer

    SciTech Connect

    Ul-Hamid, Anwar . E-mail: anwar@kfupm.edu.sa; Tawancy, Hani M.; Mohammed, Abdul-Rashid I.; Al-Jaroudi, Said S.; Abbas, Nureddin M.

    2006-04-15

    In this paper, the procedure for conducting quantitative elemental analysis by ZAF correction method using wavelength dispersive X-ray spectroscopy (WDS) in an electron probe microanalyzer (EPMA) is elaborated. Analysis of a thermal barrier coating (TBC) system formed on a Ni-based single crystal superalloy is presented as an example to illustrate the analysis of samples consisting of a large number of major and minor elements. The analysis was performed by known standards and measured peak-to-background intensity ratios. The procedure for using separate set of acquisition conditions for major and minor element analysis is explained and its importance is stressed.

  17. 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.

  18. Image Resolution in Scanning Transmission Electron Microscopy

    SciTech Connect

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

    2008-06-26

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

  19. Entanglement-assisted electron microscopy based on a flux qubit

    SciTech Connect

    Okamoto, Hiroshi; Nagatani, Yukinori

    2014-02-10

    A notorious problem in high-resolution biological electron microscopy is radiation damage caused by probe electrons. Hence, acquisition of data with minimal number of electrons is of critical importance. Quantum approaches may represent the only way to improve the resolution in this context, but all proposed schemes to date demand delicate control of the electron beam in highly unconventional electron optics. Here we propose a scheme that involves a flux qubit based on a radio-frequency superconducting quantum interference device, inserted in a transmission electron microscope. The scheme significantly improves the prospect of realizing a quantum-enhanced electron microscope for radiation-sensitive specimens.

  20. Correlated light and electron microscopy: ultrastructure lights up!

    PubMed

    de Boer, Pascal; Hoogenboom, Jacob P; Giepmans, Ben N G

    2015-06-01

    Microscopy has gone hand in hand with the study of living systems since van Leeuwenhoek observed living microorganisms and cells in 1674 using his light microscope. A spectrum of dyes and probes now enable the localization of molecules of interest within living cells by fluorescence microscopy. With electron microscopy (EM), cellular ultrastructure has been revealed. Bridging these two modalities, correlated light microscopy and EM (CLEM) opens new avenues. Studies of protein dynamics with fluorescent proteins (FPs), which leave the investigator 'in the dark' concerning cellular context, can be followed by EM examination. Rare events can be preselected at the light microscopy level before EM analysis. Ongoing development-including of dedicated probes, integrated microscopes, large-scale and three-dimensional EM and super-resolution fluorescence microscopy-now paves the way for broad CLEM implementation in biology. PMID:26020503

  1. Electron Microscopy of Biological Materials at the Nanometer Scale

    NASA Astrophysics Data System (ADS)

    Kourkoutis, Lena Fitting; Plitzko, Jürgen M.; Baumeister, Wolfgang

    2012-08-01

    Electron microscopy of biological matter uses three different imaging modalities: (a) electron crystallography, (b) single-particle analysis, and (c) electron tomography. Ideally, these imaging modalities are applied to frozen-hydrated samples to ensure an optimal preservation of the structures under scrutiny. Cryo-electron microscopy of biological matter has made important advances in the past decades. It has become a research tool that further expands the scope of structural research into unique areas of cell and molecular biology, and it could augment the materials research portfolio in the study of soft and hybrid materials. This review addresses how researchers using transmission electron microscopy can derive structural information at high spatial resolution from fully hydrated specimens, despite their sensitivity to ionizing radiation, despite the adverse conditions of high vacuum for samples that have to be kept in aqueous environments, and despite their low contrast resulting from weakly scattering building blocks.

  2. 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.

  3. 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.

  4. 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.

  5. 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 ...

  6. 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)

  7. 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

  8. Beam propagation analysis on thickness measurements in quantitative phase microscopy

    NASA Astrophysics Data System (ADS)

    Bae, Yoon-Sung; Song, Jong-In; Har, Dongsoo; Kim, Dug Young

    2015-08-01

    The two-dimensional thickness profile of a phase object can be measured by phase microscopy by assuming that the light passes straight through the sample such that the measured phase profile is proportional to the thickness of the sample. However, any non-uniform index structure in a sample bends the straight light path by refraction and diffracts the non-uniform transverse phase structure of the wavefront along the propagation path within a sample. We investigated the consequence of these two effects within a phase object using a split-step beam propagation method that considers beam paths through a 3-?m-diameter bead sample. Our simulation results show that the phase profile of light just after passing through a sample differs significantly from an ideal phase profile. We verified these simulation results by comparing them with experimental data obtained with a Mach-Zehnder interferometer.

  9. Insights into primary immune deficiency from quantitative microscopy.

    PubMed

    Mace, Emily M; Orange, Jordan S

    2015-11-01

    Recent advances in genomics-based technology have resulted in an increase in our understanding of the molecular basis of many primary immune deficiencies. Along with this increased knowledge comes an increased responsibility to understand the underlying mechanism of disease, and thus increasingly sophisticated technologies are being used to investigate the cell biology of human immune deficiencies. One such technology, which has itself undergone a recent explosion in innovation, is that of high-resolution microscopy and image analysis. These advances complement innovative studies that have previously shed light on critical cell biological processes that are perturbed by single-gene mutations in primary immune deficiency. Here we highlight advances made specifically in the following cell biological processes: (1) cytoskeletal-related processes; (2) cell signaling; (3) intercellular trafficking; and (4) cellular host defense. PMID:26078103

  10. A STUDY OF TISSUE CULTURE CELLS BY ELECTRON MICROSCOPY

    PubMed Central

    Porter, Keith R.; Claude, Albert; Fullam, Ernest F.

    1945-01-01

    By means of a tissue culture technique, cells from chick embryos were procured in a state which proved to be suitable for electron microscopy. The electron micrographs disclosed details of cell structure not revealed by other methods of examination. PMID:19871454

  11. 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.

  12. 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

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

    SciTech Connect

    Timmermans, F. J.; Otto, C.

    2015-01-15

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

  14. Stimulated excitation electron microscopy and spectroscopy.

    PubMed

    Howie, A

    2015-04-01

    Recent advances in instrumentation for electron optics and spectroscopy have prompted exploration of ultra-low excitations such as phonons, bond vibrations and Johnson noise. These can be excited not just with fast electrons but also thermally or by other external sources of radiation. The near-field theory of electron energy loss and gain provides a convenient platform for analysing these processes. Possibilities for selected phonon mapping and imaging are discussed. Effects should certainly be observable in atomic resolution structure imaging but diffraction contrast imaging could perhaps be more informative. Additional exciting prospects to be explored include the transition from phonon excitation to single atom recoil and the boosting of energy loss and gain signals with tuned laser illumination. PMID:25312246

  15. Atmospheric pressure scanning transmission electron microscopy

    SciTech Connect

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

    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.

  16. Scanning Transmission Electron Microscopy at High Resolution

    PubMed Central

    Wall, J.; Langmore, J.; Isaacson, M.; Crewe, A. V.

    1974-01-01

    We have shown that a scanning transmission electron microscope with a high brightness field emission source is capable of obtaining better than 3 Å resolution using 30 to 40 keV electrons. Elastic dark field images of single atoms of uranium and mercury are shown which demonstrate this fact as determined by a modified Rayleigh criterion. Point-to-point micrograph resolution between 2.5 and 3.0 Å is found in dark field images of micro-crystallites of uranium and thorium compounds. Furthermore, adequate contrast is available to observe single atoms as light as silver. Images PMID:4521050

  17. Subsurface atomic force microscopy: towards a quantitative understanding.

    PubMed

    Verbiest, G J; Simon, J N; Oosterkamp, T H; Rost, M J

    2012-04-13

    Recent experiments in the field of subsurface atomic force microscopy have demonstrated that it is possible to nondestructively image micro- and even nanoparticles that are embedded significantly deep within the bulk of a sample. In order to get insights into the contrast formation mechanism, we performed a finite element analysis and an analytical study, in which we calculated the amplitude and phase variation on the surface of an ultrasound wave that has traveled through the sample. Our calculations were performed as closely as possible to the situation in the experiments to enable a (future) comparison based on our predictions. We show that Rayleigh scattering of acoustic waves accounts for the measured contrast and we verify the characteristic Rayleigh dependences. The numerical results show that the contrast is independent of the depth at which a particle is buried, whereas the analytical study reveals a 1/depth dependence. In addition, we find a large deviation in the width of the particle in the contrast at the surface when applying the numerical or the analytical calculation respectively. These results indicate the importance of both the reflections of sound waves at the sample interfaces and bulk damping, as both are treated differently in our two models. PMID:22434065

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

    PubMed

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

    2015-10-20

    Ultrafast electron microscopy (UEM) is a pivotal tool for imaging of nanoscale structural dynamics with subparticle resolution on the time scale of atomic motion. Photon-induced near-field electron microscopy (PINEM), a key UEM technique, involves the detection of electrons that have gained energy from a femtosecond optical pulse via photon-electron coupling on nanostructures. PINEM has been applied in various fields of study, from materials science to biological imaging, exploiting the unique spatial, energy, and temporal characteristics of the PINEM electrons gained by interaction with a "single" light pulse. The further potential of photon-gated PINEM electrons in probing ultrafast dynamics of matter and the optical gating of electrons by invoking a "second" optical pulse has previously been proposed and examined theoretically in our group. Here, we experimentally demonstrate this photon-gating technique, and, through diffraction, visualize the phase transition dynamics in vanadium dioxide nanoparticles. With optical gating of PINEM electrons, imaging temporal resolution was improved by a factor of 3 or better, being limited only by the optical pulse widths. This work enables the combination of the high spatial resolution of electron microscopy and the ultrafast temporal response of the optical pulses, which provides a promising approach to attain the resolution of few femtoseconds and attoseconds in UEM. PMID:26438835

  19. Photon gating in four-dimensional ultrafast electron microscopy

    PubMed Central

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

    2015-01-01

    Ultrafast electron microscopy (UEM) is a pivotal tool for imaging of nanoscale structural dynamics with subparticle resolution on the time scale of atomic motion. Photon-induced near-field electron microscopy (PINEM), a key UEM technique, involves the detection of electrons that have gained energy from a femtosecond optical pulse via photon–electron coupling on nanostructures. PINEM has been applied in various fields of study, from materials science to biological imaging, exploiting the unique spatial, energy, and temporal characteristics of the PINEM electrons gained by interaction with a “single” light pulse. The further potential of photon-gated PINEM electrons in probing ultrafast dynamics of matter and the optical gating of electrons by invoking a “second” optical pulse has previously been proposed and examined theoretically in our group. Here, we experimentally demonstrate this photon-gating technique, and, through diffraction, visualize the phase transition dynamics in vanadium dioxide nanoparticles. With optical gating of PINEM electrons, imaging temporal resolution was improved by a factor of 3 or better, being limited only by the optical pulse widths. This work enables the combination of the high spatial resolution of electron microscopy and the ultrafast temporal response of the optical pulses, which provides a promising approach to attain the resolution of few femtoseconds and attoseconds in UEM. PMID:26438835

  20. Scattered electrons in microscopy and microanalysis

    SciTech Connect

    Ottensmeyer, F.P.

    1982-01-29

    The use of scattered electrons alone for direct imaging of biological specimens makes it possible to obtain structural information at atomic and near-atomic spatial resolutions of 0.3 to 0.5 nanometer. While this is not as good as the resolution possible with x-ray crystallography, such an approach provides structural information rapidly on individual macromolecules that have not been, and possibly cannot be, crystallized. Analysis of the spectrum of energies of scattered electrons and imaging of the latter with characteristic energy bands within the spectrum produce a powerful new technique of atomic microanalysis. This technique, which has a spatial resolution of about 0.5 nanometer and a minimum detection sensitivity of about 50 atoms of phosphorus, is especially useful for light atom analysis and appears to have applications in molecular biology, cell biology, histology, pathology, botany, and many other fields.

  1. Scattered electrons in microscopy and microanalysis

    SciTech Connect

    Ottensmeyer, F.P.

    1982-01-29

    The use of scattered electrons alone for direct imaging of biological specimens makes it possible to obtain structural information at atomic and near-atomic spatial resolutions of 0.3 to 0.5 nanometer. While this is not as good as the resolution possible with x-ray crystallography, such an approach provides structural information rapidly on individual macromolecules that have not been, and possibly cannot be, crystallized. Analysis of the spectrum of energies of scattered electrons and imaging of the latter with characteristic energy bands within the spectrum produces a powerful new technique of atomic microanalysis. This technique, which has a spatial resolution of about 0.5 nanometer and a minimum detection sensitivity of about 50 atoms of phosphorus, is especially useful for light atom analysis and appears to have applications in molecular biology, cell biology, histology, pathology, botany, and many other fields.

  2. 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.

  3. CI Slide: calibration slide for quantitative microscopy imaging in absorbance

    NASA Astrophysics Data System (ADS)

    Sheikhzadeh, Fahime; Ye, Qian; Zulkafly, Nasir; Carraro, Anita; Korbelic, Jagoda; Chen, Zhaoyang; Harrison, Alan; Follen, Michele; MacAulay, Calum; Ward, Rabab K.; Guillaud, Martial

    2014-03-01

    New imaging technologies are changing the field of digital pathology. This field faces numerous challenges and there is a pressing need for standardization, calibration protocols, quality control and quantitative assessment. We have designed a new calibration imaging slide (Cancer Imaging Slide), specifically to measure the characteristics of old or new imaging systems or scanners. The layout of the slide consists of 138 boxes with the side length of 1.6 mm, containing objects of known morphologic and photometric characteristics. Among them, 112 boxes contain different permutations of circles, ovals, and squares. The circles have different radii, radius/pitch ratios and step transmissions. The ovals have different sizes and orientations. The squares are consistent in size and orientation but have different step transmission values. Also, 16 boxes contain three resolution test targets: crosses, USAF target and Siemens star. The last 10 boxes are blank boxes with different transmission values. Four slides were scanned and imaged on one commercial whole-slide scanner and one high resolution imaging system. After segmenting the images, about 200 features (photometric, morphologic and architectural) were measured with our in-house image processing software. The objective of the project is to develop a statistical process control using this new slide. In this paper, we describe the characteristics of the slide and present our preliminary results.

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

    PubMed Central

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

    2015-01-01

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

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

    PubMed

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

    2015-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Venables, David; Susnitzky, David W.; Mardinly, A. John

    1998-11-01

    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.

  7. 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

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

    SciTech Connect

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

    2011-01-01

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

  9. First morphological characterization of 'Candidatus Mycoplasma turicensis' using electron microscopy.

    PubMed

    Willi, Barbara; Museux, Kristina; Novacco, Marilisa; Schraner, Elisabeth M; Wild, Peter; Groebel, Katrin; Ziegler, Urs; Wolf-Jäckel, Godelind A; Kessler, Yvonne; Geret, Catrina; Tasker, Séverine; Lutz, Hans; Hofmann-Lehmann, Regina

    2011-05-01

    At least three haemotropic mycoplasmas have been recognized in cats: Mycoplasma haemofelis (Mhf), 'Candidatus Mycoplasma haemominutum' (CMhm) and 'Candidatus M. turicensis' (CMt). The latter was originally identified in a Swiss pet cat with haemolytic anaemia and shown to be prevalent in domestic cats and wild felids worldwide using molecular methods. So far, there has been no confirmatory morphological evidence of the existence of CMt presumably due to low blood loads during infection while CMhm has only been characterized by light microscopy with discrepant results. This study aimed to provide for the first time electron microscopic characteristics of CMt and CMhm and to compare them to Mhf. Blood samples from cats experimentally infected with CMt, CMhm and Mhf were used to determine copy numbers in blood by real-time PCR and for transmission and scanning electron microscopy. High resolution scanning electron microscopy revealed CMt and CMhm to be discoid-shaped organisms of 0.3 ?m in diameter attached to red blood cells (RBCs). In transmission electron microscopy of CMt, an oval organism of about 0.25 ?m with several intracellular electron dense structures was identified close to the surface of a RBC. CMhm and CMt exhibited similar morphology to Mhf but had a smaller diameter. This is the first study to provide morphological evidence of CMt thereby confirming its status as a distinct haemoplasma species, and to present electron microscopic features of CMhm. PMID:21183295

  10. First morphological characterization of ‘Candidatus Mycoplasma turicensis’ using electron microscopy

    PubMed Central

    Willi, Barbara; Museux, Kristina; Novacco, Marilisa; Schraner, Elisabeth M.; Wild, Peter; Groebel, Katrin; Ziegler, Urs; Wolf-Jäckel, Godelind A.; Kessler, Yvonne; Geret, Catrina; Tasker, Séverine; Lutz, Hans; Hofmann-Lehmann, Regina

    2011-01-01

    At least three haemotropic mycoplasmas have been recognized in cats: Mycoplasma haemofelis (Mhf), ‘Candidatus Mycoplasma haemominutum’ (CMhm) and ‘Candidatus M. turicensis’ (CMt). The latter was originally identified in a Swiss pet cat with haemolytic anaemia and shown to be prevalent in domestic cats and wild felids worldwide using molecular methods. So far, there has been no confirmatory morphological evidence of the existence of CMt presumably due to low blood loads during infection while CMhm has only been characterized by light microscopy with discrepant results. This study aimed to provide for the first time electron microscopic characteristics of CMt and CMhm and to compare them to Mhf. Blood samples from cats experimentally infected with CMt, CMhm and Mhf were used to determine copy numbers in blood by real-time PCR and for transmission and scanning electron microscopy. High resolution scanning electron microscopy revealed CMt and CMhm to be discoid-shaped organisms of 0.3 ?m in diameter attached to red blood cells (RBCs). In transmission electron microscopy of CMt, an oval organism of about 0.25 ?m with several intracellular electron dense structures was identified close to the surface of a RBC. CMhm and CMt exhibited similar morphology to Mhf but had a smaller diameter. This is the first study to provide morphological evidence of CMt thereby confirming its status as a distinct haemoplasma species, and to present electron microscopic features of CMhm. PMID:21183295

  11. Hybrid shear force feedback/scanning quantitative phase microscopy applied to subsurface imaging.

    PubMed

    Edward, Kert; Farahi, Faramarz; Hocken, Robert

    2009-10-12

    Quantitative phase microscopy allows for the study of the surface morphology and dynamics of transparent biological specimens. Although phase data often contains coupled subsurface information, decoupling the surface and subsurface components is often very difficult or impossible. We hereby present a simple procedure which exploits simultaneous obtained quantitative phase and shear-force feedback topography data to extract subsurface sample information. Our results reveal subsurface features in fabricated samples and fish erythrocytes. PMID:20372571

  12. 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.

  13. Microscopy with slow electrons: from LEEM to XPEEM

    ScienceCinema

    Bauer, Ernst [Arizona State University, Phoenix, Arizona, United States

    2010-01-08

    The short penetration and escape depth of electrons with energies below 1 keV make them ideally suited for the study of surfaces and ultrathin films. The combination of the low energy electrons and the high lateral resolution of a microscope produces a powerful method for the characterization of nanostructures on bulk samples, in particular if the microscope is equipped with an imaging energy filter and connected to a synchrotron radiation source. Comprehensive characterization by imaging, diffraction, and spectroscope of the structural, chemical, and magnetic properties is then possible. The Talk will describe the various imaging techniques in using reflected and emitted electrons in low-energy electron microscopy (LEEM) and x-ray photoemission electron microscopy (XPEEM), with an emphasis on magnetic materials with spin-polarized LEEM and x-ray magnetic circular dichroism PEEM. The talk with end with an outlook on future possibilities.

  14. Directed evolution of APEX2 for electron microscopy and proteomics

    PubMed Central

    Lam, Stephanie S.; Martell, Jeffrey D.; Kamer, Kimberli J.; Deerinck, Thomas J.; Ellisman, Mark H.; Mootha, Vamsi K.; Ting, Alice Y.

    2014-01-01

    APEX is an engineered peroxidase that functions both as an electron microscopy tag, and as a promiscuous labeling enzyme for live-cell proteomics. Because the limited sensitivity of APEX precludes applications requiring low APEX expression, we used yeast display evolution to improve its catalytic efficiency. Our evolved APEX2 is far more active in cells, enabling the superior enrichment of endogenous mitochondrial and endoplasmic reticulum membrane proteins and the use of electron microscopy to resolve the sub-mitochondrial localization of calcium uptake regulatory protein MICU1. PMID:25419960

  15. 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.

  16. Towards Automated Nanomanipulation under Scanning Electron Microscopy

    NASA Astrophysics Data System (ADS)

    Ye, Xutao

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

  17. Direct investigation of subsurface interface electronic structure by ballistic-electron-emission microscopy

    NASA Technical Reports Server (NTRS)

    Kaiser, W. J.; Bell, L. D.

    1988-01-01

    A new technique for spectroscopic investigation of subsurface interface electronic structure has been developed. The method, ballistic-electron-emission microscopy (BEEM), is based on scanning tunneling microscopy. BEEM makes possible, for the first time, direct imaging of subsurface interface properties with nanometer spatial resolution. The first application of BEEM to subsurface Schottky-barrier interfaces is reported.

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

    PubMed

    Chrapo?ski, J; Rodak, K

    2006-09-01

    The aim of this work was to assess the changes in the microstructure of hot-deformed specimens made of alloys containing 46-50 at.% Al, 2 at.% Cr and 2 at.% Nb (and alloying additions such as carbon and boron) with the aid of scanning electron microscopy and transmission electron microscopy techniques. After homogenization and heat treatment performed in order to make diverse lamellae thickness, the specimens were compressed at 1000 degrees C. Transmission electron microscopy examinations of specimens after the compression test revealed the presence of heavily deformed areas with a high density of dislocation. Deformation twins were also observed. Dynamically recrystallized grains were revealed. For alloys no. 2 and no. 3, the recovery and recrystallization processes were more extensive than for alloy no. 1. PMID:17059556

  19. Electron Microscopy of Nephropathia Epidemica. Glomerular changes.

    PubMed

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

    1978-02-10

    Electron microscopical changes in the glomeruli in 20 kidney biopsies from 18 patients, who were suffering from or had lately suffered from Nephropathia epidemica were studied. Various kinds of deposits were seen. Under the endothelial cells there were collections of light flocculent material. Small dark deposits were seen in the mesangium at the mesangial cell processes, inside the thickened basement membrane, and occasionally on the epithelial side of the membrane. Large deposits were seen around mesangial cells in the mesangium. Deposits were less numerous than in chronic immune complex diseases. The intramembranous or subepithelial deposits were associated with "moon craters", membranous convoluted structures or membrane debris. Granular extracellular mesangial material, round extracellular particles and intraendothelial microtubular inclusions were occasionally seen. In two of our cases occasional capsular epithelial cells showed numerous myelin bodies. Typical viruses were not seen in the glomeruli. The findings are in accord with the short period of scanty immune complex deposition in the glomeruli in the clinically active phase of Nephropathia epidemica. PMID:205038

  20. Imaging doped silicon test structures using low energy electron microscopy.

    SciTech Connect

    Nakakura, Craig Yoshimi; Anderson, Meredith Lynn; Kellogg, Gary Lee

    2010-01-01

    This document is the final SAND Report for the LDRD Project 105877 - 'Novel Diagnostic for Advanced Measurements of Semiconductor Devices Exposed to Adverse Environments' - funded through the Nanoscience to Microsystems investment area. Along with the continuous decrease in the feature size of semiconductor device structures comes a growing need for inspection tools with high spatial resolution and high sample throughput. Ideally, such tools should be able to characterize both the surface morphology and local conductivity associated with the structures. The imaging capabilities and wide availability of scanning electron microscopes (SEMs) make them an obvious choice for imaging device structures. Dopant contrast from pn junctions using secondary electrons in the SEM was first reported in 1967 and more recently starting in the mid-1990s. However, the serial acquisition process associated with scanning techniques places limits on the sample throughput. Significantly improved throughput is possible with the use of a parallel imaging scheme such as that found in photoelectron emission microscopy (PEEM) and low energy electron microscopy (LEEM). The application of PEEM and LEEM to device structures relies on contrast mechanisms that distinguish differences in dopant type and concentration. Interestingly, one of the first applications of PEEM was a study of the doping of semiconductors, which showed that the PEEM contrast was very sensitive to the doping level and that dopant concentrations as low as 10{sup 16} cm{sup -3} could be detected. More recent PEEM investigations of Schottky contacts were reported in the late 1990s by Giesen et al., followed by a series of papers in the early 2000s addressing doping contrast in PEEM by Ballarotto and co-workers and Frank and co-workers. In contrast to PEEM, comparatively little has been done to identify contrast mechanisms and assess the capabilities of LEEM for imaging semiconductor device strictures. The one exception is the work of Mankos et al., who evaluated the impact of high-throughput requirements on the LEEM designs and demonstrated new applications of imaging modes with a tilted electron beam. To assess its potential as a semiconductor device imaging tool and to identify contrast mechanisms, we used LEEM to investigate doped Si test structures. In section 2, Imaging Oxide-Covered Doped Si Structures Using LEEM, we show that the LEEM technique is able to provide reasonably high contrast images across lateral pn junctions. The observed contrast is attributed to a work function difference ({Delta}{phi}) between the p- and n-type regions. However, because the doped regions were buried under a thermal oxide ({approx}3.5 nm thick), e-beam charging during imaging prevented quantitative measurements of {Delta}{phi}. As part of this project, we also investigated a series of similar test structures in which the thermal oxide was removed by a chemical etch. With the oxide removed, we obtained intensity-versus-voltage (I-V) curves through the transition from mirror to LEEM mode and determined the relative positions of the vacuum cutoffs for the differently doped regions. Although the details are not discussed in this report, the relative position in voltage of the vacuum cutoffs are a direct measure of the work function difference ({Delta}{phi}) between the p- and n-doped regions.

  1. 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

  2. Dynamic tunneling force microscopy for characterizing electronic trap states in non-conductive surfaces

    NASA Astrophysics Data System (ADS)

    Wang, R.; Williams, C. C.

    2015-09-01

    Dynamic tunneling force microscopy (DTFM) is a scanning probe technique for real space mapping and characterization of individual electronic trap states in non-conductive films with atomic scale spatial resolution. The method is based upon the quantum mechanical tunneling of a single electron back and forth between a metallic atomic force microscopy tip and individual trap states in completely non-conducting surface. This single electron shuttling is measured by detecting the electrostatic force induced on the probe tip at the shuttling frequency. In this paper, the physical basis for the DTFM method is unfolded through a physical model and a derivation of the dynamic tunneling signal as a function of several experimental parameters is shown. Experimental data are compared with the theoretical simulations, showing quantitative consistency and verifying the physical model used. The experimental system is described and representative imaging results are shown.

  3. Dynamic tunneling force microscopy for characterizing electronic trap states in non-conductive surfaces.

    PubMed

    Wang, R; Williams, C C

    2015-09-01

    Dynamic tunneling force microscopy (DTFM) is a scanning probe technique for real space mapping and characterization of individual electronic trap states in non-conductive films with atomic scale spatial resolution. The method is based upon the quantum mechanical tunneling of a single electron back and forth between a metallic atomic force microscopy tip and individual trap states in completely non-conducting surface. This single electron shuttling is measured by detecting the electrostatic force induced on the probe tip at the shuttling frequency. In this paper, the physical basis for the DTFM method is unfolded through a physical model and a derivation of the dynamic tunneling signal as a function of several experimental parameters is shown. Experimental data are compared with the theoretical simulations, showing quantitative consistency and verifying the physical model used. The experimental system is described and representative imaging results are shown. PMID:26429449

  4. Quantitative Fluorescence Microscopy autofocusing, z-axis calibration, image sensors, fluorescence lifetime imaging

    E-print Network

    van Vliet, Lucas J.

    : waves and particles 47 Introduction to CCD cameras 49 Properties of CCD cameras 52 Introduction to image-intensifiers 64 Properties of image-intensifiers 68 Special applications of image-intensifiers 74 PhotometricQuantitative Fluorescence Microscopy autofocusing, z-axis calibration, image sensors, fluorescence

  5. 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.

  6. Entanglement-assisted electron microscopy based on a flux qubit

    E-print Network

    Hiroshi Okamoto; Yukinori Nagatani

    2013-11-11

    A notorious problem in high-resolution biological electron microscopy is radiation damage to the specimen caused by probe electrons. Hence, acquisition of data with minimal number of electrons is of critical importance. Quantum approaches may represent the only way to improve the resolution in this context, but all proposed schemes to date demand delicate control of the electron beam in highly unconventional electron optics. Here we propose a scheme that involves a flux qubit based on a radio-frequency superconducting quantum interference device (rf-SQUID), inserted in essentially a conventional transmission electron microscope. The scheme significantly improves the prospect of realizing a quantum-enhanced electron microscope for radiation-sensitive specimens.

  7. A national facility for biological cryo-electron microscopy

    SciTech Connect

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

    2015-01-01

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

  8. Detection of parvoviruses in wolf feces by electron microscopy

    USGS Publications Warehouse

    Muneer, M.A.; Farah, I.O.; Pomeroy, K.A.; Goyal, S.M.; Mech, L.D.

    1988-01-01

    One hundred fifteen wolf (Canis lupus) feces were collected between 1980 and 1984 from northeastern Minnesota and were examined for canine parvovirus by negative contrast electron microscopy. Of these, seven (6%) samples revealed the presence of parvovirus. Some of these viruses were able to grow in cell cultures forming intranuclear inclusion bodies and giant cells.

  9. 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

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

    ERIC Educational Resources Information Center

    Bogle, Stephanie Nicole

    2009-01-01

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

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

    ERIC Educational Resources Information Center

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

    2009-01-01

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

  12. Microstress contrast in scanning electron acoustic microscopy of ceramics

    NASA Technical Reports Server (NTRS)

    Cantrell, John H.; Qian, Menglu

    1991-01-01

    A mathematical model of image contrast in scanning electron acoustic microscopy (SEAM) due to the effect of residual stresses in materials is presented. It is found that in regions near the ends of the radial cracks induced by Vickers indentation the SEAM micrographs reveal a rather large variation of the acoustic output signal.

  13. Molecular and Cellular Quantitative Microscopy: theoretical investigations, technological developments and applications to neurobiology

    NASA Astrophysics Data System (ADS)

    Esposito, Alessandro

    2006-05-01

    This PhD project aims at the development and evaluation of microscopy techniques for the quantitative detection of molecular interactions and cellular features. The primarily investigated techniques are F?rster Resonance Energy Transfer imaging and Fluorescence Lifetime Imaging Microscopy. These techniques have the capability to quantitatively probe the biochemical environment of fluorophores. An automated microscope capable of unsupervised operation has been developed that enables the investigation of molecular and cellular properties at high throughput levels and the analysis of cellular heterogeneity. State-of-the-art Förster Resonance Energy Transfer imaging, Fluorescence Lifetime Imaging Microscopy, Confocal Laser Scanning Microscopy and the newly developed tools have been combined with cellular and molecular biology techniques for the investigation of protein-protein interactions, oligomerization and post-translational modifications of ?-Synuclein and Tau, two proteins involved in Parkinson’s and Alzheimer’s disease, respectively. The high inter-disciplinarity of this project required the merging of the expertise of both the Molecular Biophysics Group at the Debye Institute - Utrecht University and the Cell Biophysics Group at the European Neuroscience Institute - G?ttingen University. This project was conducted also with the support and the collaboration of the Center for the Molecular Physiology of the Brain (Göttingen), particularly with the groups associated with the Molecular Quantitative Microscopy and Parkinson’s Disease and Aggregopathies areas. This work demonstrates that molecular and cellular quantitative microscopy can be used in combination with high-throughput screening as a powerful tool for the investigation of the molecular mechanisms of complex biological phenomena like those occurring in neurodegenerative diseases.

  14. 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

  15. Reactive gas plasma specimen processing for use in microanalysis and imaging in analytical electron microscopy

    SciTech Connect

    Zaluzec, N.J.; Kestel, B.J.; Henriks, D.

    1997-01-01

    It has long been the bane of analytical electron microscopy (AEM) that the use of focused probes during microanalysis of specimens increases the local rate of hydrocarbon contamination. This is most succinctly observed by the formation of contamination deposits during focused probe work typical of AEM studies. While serving to indicate the location of the electron probe, the contamination obliterates the area of the specimen being analyzed and adversely affects all quantitative microanalysis methodologies. A variety of methods including: UV, electron beam flooding, heating and/or cooling can decrease the rate of contamination, however, none of these methods directly attack the source of specimen borne contamination. Research has shown that reactive gas plasmas may be used to clean both the specimen and stage for AEM, in this study the authors report on quantitative measurements of the reduction in contamination rates in an AEM as a function of operating conditions and plasma gases.

  16. Electron holography and environmental transmission electron microscopy of magnetism at the nanoscale

    E-print Network

    Dunin-Borkowski, Rafal E.

    Electron holography and environmental transmission electron microscopy of magnetism B. Boothroyd, Jörg R. Jinschek, Zi-An Li and Michael Farle The addition of an electron biprism to a transmission electron microscope (TEM) equipped with a field emission gun allows the phase shift

  17. Polyvinylidene fluoride molecules in nanofibers, imaged at atomic scale by aberration corrected electron microscopy.

    PubMed

    Lolla, Dinesh; Gorse, Joseph; Kisielowski, Christian; Miao, Jiayuan; Taylor, Philip L; Chase, George G; Reneker, Darrell H

    2015-12-17

    Atomic scale features of polyvinylidene fluoride molecules (PVDF) were observed with aberration corrected transmission electron microscopy. Thin, self-supporting PVDF nanofibers were used to create images that show conformations and relative locations of atoms in segments of polymer molecules, particularly segments near the surface of the nanofiber. Rows of CF2 atomic groups, at 0.25 nm intervals, which marked the paths of segments of the PVDF molecules, were seen. The fact that an electron microscope image of a segment of a PVDF molecule depended upon the particular azimuthal direction, along which the segment was viewed, enabled observation of twist around the molecular axis. The 0.2 nm side-by-side distance between the two fluorine atoms attached to the same carbon atom was clearly resolved. Morphological and chemical changes produced by energetic electrons, ranging from no change to fiber scission, over many orders of magnitude of electrons per unit area, promise quantitative new insights into radiation chemistry. Relative movements of segments of molecules were observed. Promising synergism between high resolution electron microscopy and molecular dynamic modeling was demonstrated. This paper is at the threshold of growing usefulness of electron microscopy to the science and engineering of polymer and other molecules. PMID:26369731

  18. Characterization of interfacial reactions in magnetite tunnel junctions with transmission electron microscopy

    E-print Network

    Laughlin, David E.

    transmission electron microscopy and x-ray energy dispersive spectroscopy to investigate the interfacial fully understood. Since high resolution transmission electron microscopy HRTEM has the abilityCharacterization of interfacial reactions in magnetite tunnel junctions with transmission electron

  19. 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 be determined by X-ray and neutron diffraction, while transmission electron microscopy (TEM) is indispensable properties of nanophase materials rely on their crystal and surface structures. Transmission electron

  20. An electromechanical material testing system for in situ electron microscopy and applications

    E-print Network

    Espinosa, Horacio D.

    An electromechanical material testing system for in situ electron microscopy and applications Yong for in situ electron microscopy (EM) mechanical testing of nanostructures. The testing system consists and failure with subnanometer resolution, while simultaneously measuring the applied load electronically

  1. Characterization of Catalysts for Synthesis of Higher Alcohols using Electron Microscopy

    E-print Network

    Dunin-Borkowski, Rafal E.

    electron microscopy is a valuable tool for characterization of various materials is to characterize these new candidates by electron microscopy. This poster covers the principle methods Characterization of Catalysts for Synthesis of Higher Alcohols using Electron

  2. Biominerals at the nanoscale: transmission electron microscopy methods for studying the special properties of biominerals

    E-print Network

    Dunin-Borkowski, Rafal E.

    Biominerals at the nanoscale: transmission electron microscopy methods for studying the special, strictly controlled physical and chemical properties. Transmission electron microscopy is ideally suited bacterium, obtained from electron holography. The parallel magnetic contours and uniform blue color indicate

  3. Multi-color correlative light and electron microscopy using nanoparticle cathodoluminescence

    E-print Network

    Walsworth, Ronald L.

    1 Multi-color correlative light and electron microscopy using nanoparticle cathodoluminescence D. Introduction: The correlation of light microscopy with electron microscopy offers considerable scope for new materials [11]). Furthermore, in conjunction with evolving techniques for wet electron microscopy [12], NP

  4. [21] Visualization and Characterization of Receptor Clusters by Transmission Electron Microscopy

    E-print Network

    Cairo, Christopher W.

    [21] Visualization and Characterization of Receptor Clusters by Transmission Electron Microscopy-field optical microscopy,27­30 analytical ultracentrifugation, circular dichroism,31 electrospray ionization

  5. Transmission Electron Microscopy of a Graphene-based Polymer Nanocomposite

    NASA Astrophysics Data System (ADS)

    Kohlhaas, Kevin; Dikin, Dmitriy; Stankovich, Sasha; Ruoff, Rodney; Stach, Eric

    2006-03-01

    A Polystyrene/CMG (chemically modified graphene) composite has been made by a solution-based processing technique followed by hot pressing or injection molding to form continuous specimens. Microtomed samples were prepared for study by transmission (TEM) and scanning (SEM) electron microscopy. The electron diffraction patterns and the resulting d-spacings, as well as high-resolution bright field TEM images, suggest that the platelets are individual graphene sheets randomly dispersed in the polymer matrix. Scanning electron microscopy observation indicates that the sheets are in a wrinkled conformation; this wrinkling has also been observed in TEM, in the form of 10 nm “domains” exhibiting lattice fringes of varying orientations. We gratefully acknowledge the NASA University Research, Engineering and Technology Institute on Bio Inspired Materials (BIMat; No. NCC-1-02037) and the National Science Foundation (No. DMR-0526959).

  6. Opportunities and challenges in liquid cell electron microscopy.

    PubMed

    Ross, Frances M

    2015-12-18

    Transmission electron microscopy offers structural and compositional information with atomic resolution, but its use is restricted to thin, solid samples. Liquid samples, particularly those involving water, have been challenging because of the need to form a thin liquid layer that is stable within the microscope vacuum. Liquid cell electron microscopy is a developing technique that allows us to apply the powerful capabilities of the electron microscope to imaging and analysis of liquid specimens. We describe its impact in materials science and biology. We discuss how its applications have expanded via improvements in equipment and experimental techniques, enabling new capabilities and stimuli for samples in liquids, and offering the potential to solve grand challenge problems. PMID:26680204

  7. 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.

  8. Electron Microscopy of Probability Currents at Atomic Resolution.

    PubMed

    Lubk, A; Béché, A; Verbeeck, J

    2015-10-23

    Atomic resolution transmission electron microscopy records the spatially resolved scattered electron density to infer positions, density, and species of atoms. These data are indispensable for studying the relation between structure and properties in solids. Here, we show how this signal can be augmented by the lateral probability current of the scattered electrons in the object plane at similar resolutions and fields of view. The currents are reconstructed from a series of three atomic resolution TEM images recorded under a slight difference of perpendicular line foci. The technique does not rely on the coherence of the electron beam and can be used to reveal electric, magnetic, and strain fields with incoherent electron beams as well as correlations in inelastic transitions, such as electron magnetic chiral dichroism. PMID:26551126

  9. Electron Microscopy of Probability Currents at Atomic Resolution

    NASA Astrophysics Data System (ADS)

    Lubk, A.; Béché, A.; Verbeeck, J.

    2015-10-01

    Atomic resolution transmission electron microscopy records the spatially resolved scattered electron density to infer positions, density, and species of atoms. These data are indispensable for studying the relation between structure and properties in solids. Here, we show how this signal can be augmented by the lateral probability current of the scattered electrons in the object plane at similar resolutions and fields of view. The currents are reconstructed from a series of three atomic resolution TEM images recorded under a slight difference of perpendicular line foci. The technique does not rely on the coherence of the electron beam and can be used to reveal electric, magnetic, and strain fields with incoherent electron beams as well as correlations in inelastic transitions, such as electron magnetic chiral dichroism.

  10. Multimode quantitative scanning microwave microscopy of in situ grown epitaxial Ba1xSrxTiO3 composition spreads

    E-print Network

    Rubloff, Gary W.

    Multimode quantitative scanning microwave microscopy of in situ grown epitaxial Ba1ÀxSrxTiO3 have performed variable-temperature multimode quantitative microwave microscopy of in situ epitaxial Ba. Measurements are simultaneously taken at multiple resonant frequencies of the microscope cavity. The multimode

  11. 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

  12. Imaging and microanalysis of thin ionomer layers by scanning transmission electron microscopy

    SciTech Connect

    Cullen, David A; Koestner, Roland; Kukreja, Ratan; Minko, Sergiy; Trotsenko, Oleksandr; Tokarev, Alexander V; Guetaz, Laure; Meyer III, Harry M; Parish, Chad M; More, Karren Leslie

    2014-01-01

    Improved conditions for imaging and spectroscopic mapping of thin perfluorosulfonic acid (PFSA) ionomer layers in fuel cell electrodes by scanning transmission electron microscopy (STEM) have been investigated. These conditions are first identified on model systems of Nafion ionomer-coated nanostructured thin films and nanoporous Si. The optimized conditions are then applied in a quantitative study of the ionomer through-layer loading for two typical electrode catalyst coatings using electron energy loss and energy dispersive X-ray spectroscopy in the transmission electron microscope. The e-beam induced damage to the perfluorosulfonic acid (PFSA) ionomer is quantified by following the fluorine mass loss with electron exposure and is then mitigated by a few orders of magnitude using cryogenic specimen cooling and a higher incident electron voltage. Multivariate statistical analysis is also applied to the analysis of spectrum images for data denoising and unbiased separation of independent components related to the catalyst, ionomer, and support.

  13. Correlated Light and Electron Microscopy/Electron Tomography of Mitochondria In Situ

    PubMed Central

    Perkins, Guy A.; Sun, Mei G.; Frey, Terrence G.

    2009-01-01

    Three-dimensional light microscopy and three-dimensional electron microscopy (electron tomography) separately provide very powerful tools to study cellular structure and physiology, including the structure and physiology of mitochondria. Fluorescence microscopy allows one to study processes in live cells with specific labels and stains that follow the movement of labeled proteins and changes within cellular compartments but does not have sufficient resolution to define the ultrastructure of intracellular organelles such as mitochondria. Electron microscopy and electron tomography provide the highest resolution currently available to study mitochondrial ultrastructure but cannot follow processes in living cells. We describe the combination of these two techniques in which fluorescence confocal microscopy is used to study structural and physiologic changes in mitochondria within apoptotic HeLa cells to define the apoptotic timeframe. Cells can then be selected at various stages of the apoptotic timeframe for examination at higher resolution by electron microscopy and electron tomography. This is a form of “virtual” 4-dimensional electron microscopy that has revealed interesting structural changes in the mitochondria of HeLa cells during apoptosis. The same techniques can be applied, with modification, to study other dynamic processes within cells in other experimental contexts. PMID:19348881

  14. Total internal reflection holographic microscopy (TIRHM) for quantitative phase characterization of cell-substrate adhesion

    NASA Astrophysics Data System (ADS)

    Ash, William Mason, III

    Total Internal Reflection Holographic Microscopy (TIRHM) combines near-field microscopy with digital holography to produce a new form of near-field phase microscopy. Using a prism in TIR as a near-field imager, the presence of microscopic organisms, cell-substrate interfaces, and adhesions, causes relative refractive index (RRI) and frustrated TIR (f-TIR) to modulate the object beam's evanescent wave phase front. Quantitative phase images of test specimens such as Amoeba proteus, Dictyostelium Discoideum and cells such as SKOV-3 ovarian cancer and 3T3 fibroblasts are produced without the need to introduce stains or fluorophores. The angular spectrum method of digital holography to compensate for tilt anamorphism due to the inclined TIR plane is also discussed. The results of this work conclusively demonstrate, for the first time, the integration of near-field microscopy with digital holography. The cellular images presented show a correlation between the physical extent of the Amoeba proteus plasma membrane and the adhesions that are quantitatively profiled by phase cross-sectioning of the holographic images obtained by digital holography. With its ability to quantitatively characterise cellular adhesion and motility, it is anticipated that TIRHM can be a tool for characterizing and combating cancer metastasis, as well as improving our understanding of morphogenesis and embryogenesis itself.

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

    SciTech Connect

    Sacci, Robert L; Dudney, Nancy J; More, Karren Leslie; Browning, Nigel; Unocic, Raymond R

    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.

  16. Biological imaging with 4D ultrafast electron microscopy

    PubMed Central

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

    2010-01-01

    Advances in the imaging of biological structures with transmission electron microscopy continue to reveal information at the nanometer length scale and below. The images obtained are static, i.e., time-averaged over seconds, and the weak contrast is usually enhanced through sophisticated specimen preparation techniques and/or improvements in electron optics and methodologies. Here we report the application of the technique of photon-induced near-field electron microscopy (PINEM) to imaging of biological specimens with femtosecond (fs) temporal resolution. In PINEM, the biological structure is exposed to single-electron packets and simultaneously irradiated with fs laser pulses that are coincident with the electron pulses in space and time. By electron energy-filtering those electrons that gained photon energies, the contrast is enhanced only at the surface of the structures involved. This method is demonstrated here in imaging of protein vesicles and whole cells of Escherichia coli, both are not absorbing the photon energy, and both are of low-Z contrast. It is also shown that the spatial location of contrast enhancement can be controlled via laser polarization, time resolution, and tomographic tilting. The high-magnification PINEM imaging provides the nanometer scale and the fs temporal resolution. The potential of applications is discussed and includes the study of antibodies and immunolabeling within the cell. PMID:20479261

  17. 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.

  18. A Mobile Nanoscience and Electron Microscopy Outreach Program

    NASA Astrophysics Data System (ADS)

    Coffey, Tonya; Kelley, Kyle

    2013-03-01

    We have established a mobile nanoscience laboratory outreach program in Western NC that puts scanning electron microscopy (SEM) directly in the hands of K-12 students and the general public. There has been a recent push to develop new active learning materials to educate students at all levels about nanoscience and nanotechnology. Previous projects, such as Bugscope, nanoManipulator, or SPM Live! allowed remote access to advanced microscopies. However, placing SEM directly in schools has not often been possible because the cost and steep learning curve of these technologies were prohibitive, making this project quite novel. We have developed new learning modules for a microscopy outreach experience with a tabletop SEM (Hitachi TM3000). We present here an overview of our outreach and results of the assessment of our program to date.

  19. Human enamel structure studied by high resolution electron microscopy

    SciTech Connect

    Wen, S.L. )

    1989-01-01

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

  20. Is transmission electron microscopy (TEM) a promising approach for qualitative and quantitative investigations of polymyxin B and miconazole interactions with cellular and subcellular structures of Staphylococcus pseudintermedius, Escherichia coli, Pseudomonas aeruginosa and Malassezia pachydermatis?

    PubMed

    Voget, Michael; Lorenz, Dorothea; Lieber-Tenorio, Elisabeth; Hauck, Ruediger; Meyer, Michael; Cieslicki, Michael

    2015-12-31

    Antimicrobial therapy using a combination of polymyxin B and miconazole is effective against the main bacterial pathogens associated with otitis externa in dogs, and a synergistic effect of both drugs has been shown previously. The objective of the present investigation was to visualize ultrastructural changes after exposure of Escherichia coli, Pseudomonas aeruginosa, Staphylococcus pseudintermedius and Malassezia pachydermatis to polymyxin B and miconazole by transmission electron microscopic (TEM). For this, cultures of E. coli, P. aeruginosa, S. pseudintermedius and M. pachydermatis were exposed to polymyxin B and miconazole, alone or in combination for 24h. Ultrastructural changes were observed most frequently in the cell envelope of the four microorganisms. Exposure to polymyxin B seemed to cause more damage than miconazole within the range of concentrations applied. Treatment resulted in changes of the cell size: in E. coli, cell size increased significantly after treatment with either compound alone; in P. aeruginosa, cell size decreased significantly after treatment with polymyxin B and with miconazole; exposure of S. pseudintermedius to miconazole caused a decrease in cell size; in M. pachydermatis, cell size increased significantly after treatment with polymyxin B.; in E.coli, S. pseudintermedius and M. pachydermatis, cell size changed highly significant, in P. aeruginosa significantly after exposure to the combination of both compounds. In conclusion, by using a different approach than previous investigations, this study confirmed a clear combinatory effect of polymyxin B and miconazole against the tested microorganisms involved in canine otitis externa. It is the first time that visualization technologies were applied to compare the effect of single drugs to their combinatory effects on cellular and subcellular entities of selected bacterial and yeast species. PMID:26527257

  1. "Frontiers of Biological Electron Microscopy-Proteins to Supramolecules" 15 3 1215 4

    E-print Network

    Miyashita, Yasushi

    359 COE 30 "Frontiers of Biological Electron Microscopy-Proteins to Supramolecules" 15 3 for Transmission Electron Microscopy 8. K. Nagayama (CIBS, ONRI) Image Enhancement with Phase Plates in Electron for biological structure research 11. Y. Takai (Osaka Univ.) Real-time Phase Transmission Electron Microscopy. 12

  2. Inner-Shell Excitation Spectroscopy and X-ray Photoemission Electron Microscopy of Adhesion Promoters

    E-print Network

    Hitchcock, Adam P.

    Inner-Shell Excitation Spectroscopy and X-ray Photoemission Electron Microscopy of Adhesion spectra from X-ray photoemission electron microscopy of as-spun and cured vinyltriacetoxysilane of techniques including atomic force microscopy (AFM), electron energy loss (EELS) using transmission electron

  3. In Situ Transmission Electron Microscopy and Ion Irradiation of Ferritic Materials

    E-print Network

    Motta, Arthur T.

    In Situ Transmission Electron Microscopy and Ion Irradiation of Ferritic Materials MARQUIS A. KIRK The intermediate voltage electron microscope-tandem user facility in the Electron Microscopy Center at Argonne National Laboratory is described. The primary purpose of this facil- ity is electron microscopy

  4. A Genetically Encoded Tag for Correlated Light and Electron Microscopy of Intact Cells, Tissues, and

    E-print Network

    Tsien, Roger Y.

    A Genetically Encoded Tag for Correlated Light and Electron Microscopy of Intact Cells, Tissues of America Abstract Electron microscopy (EM) achieves the highest spatial resolution in protein localization via electron tomography or serial section block face scanning electron microscopy. EM shows that mini

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

    E-print Network

    #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 of transport. Heiken (1972, 1974) and #12;LAUR-82-1433 Wohletz and Krinsley: Scanning Electron Microscopy... 2

  6. Thickness determination of few-layer hexagonal boron nitride films by scanning electron microscopy and Auger electron spectroscopy

    SciTech Connect

    Sutter, P. Sutter, E.

    2014-09-01

    We assess scanning electron microscopy (SEM) and Auger electron spectroscopy (AES) for thickness measurements on few-layer hexagonal boron nitride (h-BN), the layered dielectric of choice for integration with graphene and other two-dimensional materials. Observations on h-BN islands with large, atomically flat terraces show that the secondary electron intensity in SEM reflects monolayer height changes in films up to least 10 atomic layers thickness. From a quantitative analysis of AES data, the energy-dependent electron escape depth in h-BN films is deduced. The results show that AES is suitable for absolute thickness measurements of few-layer h-BN of 1 to 6 layers.

  7. Book Review published by Analysis, 1997: Reflection Electron Microscopy and Spectroscopy for Surface Analysis, By Zhong Lin Wang

    E-print Network

    Wang, Zhong L.

    Book Review published by Analysis, 1997: Reflection Electron Microscopy and Spectroscopy. These are RHEED (reflection high energy electron diffraction), REM (reflection electron microscopy), SREM. There are many applications of reflection electron microscopy and spectroscopy scattered throughout the book

  8. Workshop on Magnetotactic Bacteria 9-11 June 2008, Balatonfred, Hungary Advanced electron microscopy techniques for studying

    E-print Network

    Dunin-Borkowski, Rafal E.

    , University of Pannonia, Veszprém, Hungary Several advanced transmission electron microscopy techniques using new and emerging electron microscopy techniques, including aberration-corrected electron microscopy, focused ion beam sectioning, live cell imaging in both transmission and scanning electron

  9. Role of electron microscopy in metastatic endometrial stromal tumors.

    PubMed

    Dickersin, G R; Scully, R E

    1993-01-01

    Endometrial stromal tumors may pose a problem in diagnosis when they appear as metastatic lesions without a known primary tumor. To determine the usefulness of electron microscopy in identifying them in these situations, optimally fixed low-grade stromal sarcomas (five), normal endometrial specimens (six), and malignant mesodermal mixed tumors (four) were studied. The endometrial stromal sarcomas had a general resemblance to normal proliferative endometrial stroma, being composed of undifferentiated cells, fibroblasts, and myofibroblasts. One stromal tumor showed evidence of partial epithelial differentiation. One of the four malignant mesodermal mixed tumors had a fibrosarcomalike component, but there was insufficient resemblance to normal endometrial stroma to indicate a relationship between the two. Together with a review of the literature, this study indicates that electron microscopy is useful in the diagnosis of low-grade endometrial stromal tumors by demonstrating characteristic cellular findings as well as a lack of features specific for other round cell and spindle cell neoplasms. PMID:8266599

  10. 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

  11. Microfabricated high-bandpass foucault aperture for electron microscopy

    SciTech Connect

    Glaeser, Robert; Cambie, Rossana; Jin, Jian

    2014-08-26

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

  12. Cross-sectional transmission electron microscopy of semiconductors

    SciTech Connect

    Sadana, D.K.

    1982-10-01

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

  13. Studying localized corrosion using liquid cell transmission electron microscopy

    DOE PAGESBeta

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

    2014-11-07

    Using liquid cell transmission electron microscopy (LCTEM), localized corrosion of Cu and Al thin films immersed in aqueous NaCl solutions was studied. 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. A discussion on strategies to control the onset of pitting is also presented.

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

    PubMed

    Choi, Hyunwoo; Hong, Seungbum; No, Kwangsoo

    2011-11-01

    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(31) of BaTiO(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. PMID:22128983

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

    SciTech Connect

    Choi, H.; Hong, S.; No, K.

    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.

  16. Approach for investigating the astigmatism of a magnetic prism in low-energy electron microscopy

    NASA Astrophysics Data System (ADS)

    Kan, H.-C.; Auerbach, Daniel; Phaneuf, R. J.

    2003-02-01

    We report an approach for investigating the electron optical properties of a magnetic prism, which includes experimental measurement of the focal point positions and the focal lengths of a magnetic prism and a direct comparison between the measurement and the electron optical simulation. We applied this approach to the magnetic prism we constructed as the beam separator for our low-energy electron microscope (LEEM). The magnetic prism consists of two sets of concentric round pole pieces and a rectangular housing as the return circuit of the magnetic flux. The experimental measurements were obtained from images of a square array of submicron size silver dots patterned on a Si(100) substrate recorded with our LEEM operated in photoemission electron microscopy mode. The measurements were compared to results of numerical simulations done with two different approaches. Both calculations agree with the measurements quantitatively.

  17. Analysis of mixed cell cultures with quantitative digital holographic phase microscopy

    NASA Astrophysics Data System (ADS)

    Kemper, Björn; Wibbeling, Jana; Ketelhut, Steffi

    2014-05-01

    In order to study, for example, the influence of pharmaceuticals or pathogens on different cell types under identical measurement conditions and to analyze interactions between different cellular specimens a minimally-invasive quantitative observation of mixed cell cultures is of particular interest. Quantitative phase microscopy (QPM) provides high resolution detection of optical path length changes that is suitable for stain-free minimally-invasive live cell analysis. Due to low light intensities for object illumination, QPM minimizes the interaction with the sample and is in particular suitable for long term time-lapse investigations, e.g., for the detection of cell morphology alterations due to drugs and toxins. Furthermore, QPM has been demonstrated to be a versatile tool for the quantification of cellular growth, the extraction morphological parameters and cell motility. We studied the feasibility of QPM for the analysis of mixed cell cultures. It was explored if quantitative phase images provide sufficient information to distinguish between different cell types and to extract cell specific parameters. For the experiments quantitative phase imaging with digital holographic microscopy (DHM) was utilized. Mixed cell cultures with different types of human pancreatic tumor cells were observed with quantitative DHM phase contrast up to 35 h. The obtained series of quantitative phase images were evaluated by adapted algorithms for image segmentation. From the segmented images the cellular dry mass and the mean cell thickness were calculated and used in the further analysis as parameters to quantify the reliability the measurement principle. The obtained results demonstrate that it is possible to characterize the growth of cell types with different morphologies in a mixed cell culture separately by consideration of specimen size and cell thickness in the evaluation of quantitative DHM phase images.

  18. Experiments in electron microscopy: from metals to nerves

    NASA Astrophysics Data System (ADS)

    Unwin, Nigel

    2015-04-01

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

  19. 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

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

    NASA Astrophysics Data System (ADS)

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

    2015-10-01

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

  1. Transmission Electron Microscopy Study of InN Nanorods

    SciTech Connect

    Liliental-Weber, Z.; Li, X.; Kryliouk, Olga; Park, H.J.; Mangum,J.; Anderson, T.

    2006-07-13

    InN nanorods were grown on a, c-, and r-plane of sapphire and also on Si (111) and GaN (0001) by non-catalytic, template-free hydride metal-organic vapor phase epitaxy and studied by transmission electron microscopy, electron energy loss (EELS) and photoluminescence (PL) at room temperature. These nanocrystals have different shapes and different faceting depending on the substrate used and their crystallographic orientation. EELS measurements have confirmed the high purity of these crystals. The observed PL peak was in the range of 0.9-0.95 eV. The strongest PL intensity was observed for the nanocrystals with the larger diameters.

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

    NASA Astrophysics Data System (ADS)

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

    2008-12-01

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

  3. System and method for compressive scanning electron microscopy

    DOEpatents

    Reed, Bryan W

    2015-01-13

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

  4. Normal-Incidence Photoemission Electron Microscopy (NI-PEEM) for Imaging Surface Plasmon Polaritons

    E-print Network

    Aeschlimann, Martin

    Normal-Incidence Photoemission Electron Microscopy (NI-PEEM) for Imaging Surface Plasmon Polaritons-field microscopy methods, nonlinear photo- emission electron microscopy (PEEM) [3, 4] has, in the last years, been normal-incidence photoemission microscopy (NI- PEEM). The change from the commonly used grazing

  5. 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. Research supported by NSF grants 092304, 0806660, 1058829 and Lock Haven University FPDC grants

  6. 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.

  7. Negative Stain Electron Microscopy of Microtubules Negative staining is a rapid, qualitative method for analyzing

    E-print Network

    Mitchison, Tim

    Negative Stain Electron Microscopy of Microtubules Negative staining is a rapid, qualitative method of microtubules into flat sheets are common. Cryo-electron microscopy, where microtubules are flash frozen

  8. Crystal fabric development and slip systems in a quartz mylonite: an approach via transmission electron microscopy

    E-print Network

    Cattin, Rodolphe

    electron microscopy and viscoplastic self-consistent modelling LUIZ F. G. MORALES1*, DAVID MAINPRICE1_grafulha@yahoo.com.br) Abstract: We have applied transmission electron microscopy (TEM) analyses coupled with viscoplastic self

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

    SciTech Connect

    Vitry, P.; Bourillot, E.; Plassard, C.; Lacroute, Y.; Lesniewska, E.; Tetard, L.

    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.

  10. Segmentation of vascular structures and hematopoietic cells in 3D microscopy images and quantitative analysis

    NASA Astrophysics Data System (ADS)

    Mu, Jian; Yang, Lin; Kamocka, Malgorzata M.; Zollman, Amy L.; Carlesso, Nadia; Chen, Danny Z.

    2015-03-01

    In this paper, we present image processing methods for quantitative study of how the bone marrow microenvironment changes (characterized by altered vascular structure and hematopoietic cell distribution) caused by diseases or various factors. We develop algorithms that automatically segment vascular structures and hematopoietic cells in 3-D microscopy images, perform quantitative analysis of the properties of the segmented vascular structures and cells, and examine how such properties change. In processing images, we apply local thresholding to segment vessels, and add post-processing steps to deal with imaging artifacts. We propose an improved watershed algorithm that relies on both intensity and shape information and can separate multiple overlapping cells better than common watershed methods. We then quantitatively compute various features of the vascular structures and hematopoietic cells, such as the branches and sizes of vessels and the distribution of cells. In analyzing vascular properties, we provide algorithms for pruning fake vessel segments and branches based on vessel skeletons. Our algorithms can segment vascular structures and hematopoietic cells with good quality. We use our methods to quantitatively examine the changes in the bone marrow microenvironment caused by the deletion of Notch pathway. Our quantitative analysis reveals property changes in samples with deleted Notch pathway. Our tool is useful for biologists to quantitatively measure changes in the bone marrow microenvironment, for developing possible therapeutic strategies to help the bone marrow microenvironment recovery.

  11. 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

  12. 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 image pairs obtained from a scanning electron microscope (SEM). Our system operates by presenting

  13. Scanning electron microscopy and energy dispersive analysis: applications in the field of cultural heritage.

    PubMed

    Schreiner, Manfred; Melcher, Michael; Uhlir, Katharina

    2007-02-01

    Scanning electron microscopy has been extensively used for the material characterization of objects of artistic and archaeological importance, especially in combination with energy dispersive X-ray microanalysis (SEM/EDX). The advantages and limitations of SEM/EDX are presented in a few case studies: analysis of pigments in cross-sections of paint layers, quantitative analysis of archaeological glass from the Roman period excavated in Ephesos/Turkey, and investigations on glasses with medieval composition concerning their weathering stability and degradation phenomena. PMID:17031630

  14. Quantitative Transmission Electron Microscopy of Magnetic Minerals T. Kasama1,*

    E-print Network

    Dunin-Borkowski, Rafal E.

    ) is ubiquitous in igneous, metamorphic and sedimentary rocks and can be used as a primary paleomagnetic recorder in rocks on the Earth and on other planets [1]. Magnetite is also found in magnetotactic bacteria and many] D.J. Dunlop & Ö. Özdemir, Rock Magnetism, Cambridge Univ. Press, 1997. [2] M. Pósfai & R.E. Dunin

  15. 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

  16. The 3-dimensional structure of a hepatitis C virus p7 ion channel by electron microscopy

    E-print Network

    The 3-dimensional structure of a hepatitis C virus p7 ion channel by electron microscopy Philipp of the HCV p7 ion channel, as determined by single-particle electron microscopy using the random conical lines the pore (15). Electron microscopy studies aimed at defining the oligomerization state of the p7

  17. Transmission Electron Microscopy: Overview and S. J. Pennycook1,2

    E-print Network

    Pennycook, Steve

    Transmission Electron Microscopy: Overview and Challenges S. J. Pennycook1,2 , A. R. Lupini1 , A-corrected scanning transmission electron microscopy that allow sub-Ångstrom beams to be used for imaging-resolution Z-contrast microscopy, electron energy loss spectroscopy and first-principles theory has proved

  18. Low-Energy Electron Microscopy Studies of Interlayer Mass Transport Kinetics on TiN(111)

    E-print Network

    Israeli, Navot

    Low-Energy Electron Microscopy Studies of Interlayer Mass Transport Kinetics on TiN(111) S) Abstract In situ low-energy electron microscopy was used to study interlayer mass transport kinetics during-energy electron microscopy, Models of surface kinetics, Single crystal surfaces, Surface morphology

  19. A clustering approach to multireference alignment of single-particle projections in electron microscopy

    E-print Network

    Xu, Guo-liang

    -particle analysis 2D analysis Multireference analysis Electron microscopy a b s t r a c t Two-dimensional analysis. Introduction Electron microscopy of single-particles is a powerful technique to analyze the structure of a large variety of biological specimens. Cryo-electron microscopy has proved able to visualize macromo

  20. In Situ Electron Microscopy Methods ``Seeing is believing'' is perhaps the mantra of every

    E-print Network

    Ferreira, Paulo J.

    In Situ Electron Microscopy Methods ``Seeing is believing'' is perhaps the mantra of every in situ of in situ microscopy is the shear breadth of experiments possible. To begin, electrons can be used advances and exciting new results at the frontier of in situ electron microscopy. Although not every

  1. Cryo-Electron-Microscopy Reconstruction of Partially Symmetric Objects Michael G. Rossmann1 and Yizhi Tao

    E-print Network

    Tao, Yizhi Jane

    Cryo-Electron-Microscopy Reconstruction of Partially Symmetric Objects Michael G. Rossmann1. 1999 Academic Press Key Words: electron microscopy; image reconstruc- tion; noncrystallographic the advent of cryo-electron microscopy (cryo- EM). A vast amount of information has been gath- ered

  2. Scanning electron microscopy study of carbon nanotubes heated at high temperatures in air

    E-print Network

    Scanning electron microscopy study of carbon nanotubes heated at high temperatures in air Xuekun Lu by scanning electron microscopy SEM to conform to the V-ridge surface topology at room temperature, which observed by scanning electron microscopy SEM throughout a sequence of heat treatments. We further report

  3. An electron microscopy study of wear in polysilicon microelectromechanical systems in ambient air

    E-print Network

    Ritchie, Robert

    An electron microscopy study of wear in polysilicon microelectromechanical systems in ambient air D for Electron Microscopy, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, United States d School in ambient air. Worn parts were examined by analytical scanning and transmission electron microscopy, while

  4. Transmission electron microscopy characterization of photocatalysts for water Filippo Cavalca1, *

    E-print Network

    Dunin-Borkowski, Rafal E.

    Transmission electron microscopy characterization of photocatalysts for water splitting Filippo of Denmark, DK-2800 Kgs. Lyngby, Denmark 4 Ernst Ruska­Centre for Microscopy and Spectroscopy with Electrons T and Komatsu T 1999 Journal of Electron Microscopy 48 361-366. 4) Hansen TW, Wagner JB and Dunin-Borkowski RE

  5. FEATURE ARTICLE Structure Analysis of Nanowires and Nanobelts by Transmission Electron Microscopy

    E-print Network

    Wang, Zhong L.

    FEATURE ARTICLE Structure Analysis of Nanowires and Nanobelts by Transmission Electron Microscopy the technical details of how to use transmission electron microscopy to correctly analyze the structure structure of 1D nanostructures. Transmission electron microscopy (TEM), as one of the most powerful tools

  6. FtsZ Condensates: An In Vitro Electron Microscopy Study David Popp,1

    E-print Network

    Erickson, Harold P.

    FtsZ Condensates: An In Vitro Electron Microscopy Study David Popp,1 Mitsusada Iwasa,1 Akihiro by fluorescent light microscopy (FLM) techniques,3,4 yet it has never been observed by direct in vivo electron microscopy. In a recent study by cryo-electron to- mography, the structure of the ring appeared to comprise

  7. The Structure of the Aquaporin-1 Water Channel: A Comparison between Cryo-electron Microscopy and

    E-print Network

    de Groot, Bert

    The Structure of the Aquaporin-1 Water Channel: A Comparison between Cryo-electron Microscopy and X been solved by cryo-electron microscopy (cryo- EM) during the last two years. Recently, the structure for the channel structure, when three groups independently presented low resolution (electron microscopy

  8. 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 t We propose a feature-based image alignment method for single-particle electron microscopy dataset. Ó 2009 Published by Elsevier Inc. 1. Introduction Single-particle electron microscopy (EM

  9. Compressed Sensing and Electron Microscopy Peter Binev, Wolfgang Dahmen, Ronald DeVore, Philipp Lamby,

    E-print Network

    DeVore, Ronald

    Compressed Sensing and Electron Microscopy Peter Binev, Wolfgang Dahmen, Ronald DeVore, Philipp this new subject has a role to play in Electron Microscopy (EM). In this paper, we shall describe microscopy, sparsity, optimal encoding and decoding. 1 Introduction Images formed from modern electron

  10. Serial Block Face-Scanning Electron Microscopy: A Method to Study Retinal

    E-print Network

    Palczewski, Krzysztof

    Serial Block Face-Scanning Electron Microscopy: A Method to Study Retinal Degenerative Phenotypes to light microscopic methods, traditional electron microscopy can provide im- ages at sufficient resolution of serial block face- scanning electron microscopy (SBF-SEM) provides the resolution needed

  11. 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 damage in electron microscopy. This might allow noninvasive molecular-resolution imaging. We show and using a scheme based on existing charged particle trapping techniques. PACS numbers: Electron microscopy

  12. Transmission electron microscopy examination of oxide layers formed on Zr alloys

    E-print Network

    Motta, Arthur T.

    Transmission electron microscopy examination of oxide layers formed on Zr alloys Aylin Yilmazbayhan, United States Received 14 July 2005; accepted 31 October 2005 Abstract A transmission electron microscopy. In this work, cross-sectional transmission electron microscopy was used to determine the morphology

  13. The Electron Microscopy Outreach Program: A Web-Based Resource for Research and Education

    E-print Network

    Gleeson, Joseph G.

    The Electron Microscopy Outreach Program: A Web-Based Resource for Research and Education Gina E and expertise for biological elec- tron microscopy. A major focus is molecular electron microscopy, but the site site, called the Electron Micros- copy (EM) Outreach Program (URL: http://em- outreach

  14. Elemental mapping in achromatic atomic-resolution energy-filtered transmission electron microscopy

    E-print Network

    Dunin-Borkowski, Rafal E.

    Elemental mapping in achromatic atomic-resolution energy-filtered transmission electron microscopy Central Facility for Electron Microscopy, RWTH Aachen University, D-52074 Aachen, Germany a r t i c l e i contrast a b s t r a c t We present atomic-resolution energy-filtered transmission electron microscopy

  15. Fitting Multimeric Protein Complexes into Electron Microscopy Maps Using 3D Zernike Descriptors

    E-print Network

    Kihara, Daisuke

    Fitting Multimeric Protein Complexes into Electron Microscopy Maps Using 3D Zernike Descriptors compared with a provided electron microscopy (EM) density map to select the ones that fit well into the EM by these methods. In recent years, cryo-electron microscopy (EM) has made significant advances to successfully

  16. Your are invited to participate in the course on Advanced Electron Microscopy (5p)

    E-print Network

    Uppsala Universitet

    Your are invited to participate in the course on Advanced Electron Microscopy (5p) (Avancerad to scanning and transmission electron microscopy. The course will give an introduction in the field as well as lectures dedicated to special electron microscopy and focused ion beam techniques. Lecturers from

  17. WAVELET FRAME BASED ALGORITHM FOR 3D RECONSTRUCTION IN ELECTRON MICROSCOPY

    E-print Network

    Shen, Zuowei

    WAVELET FRAME BASED ALGORITHM FOR 3D RECONSTRUCTION IN ELECTRON MICROSCOPY MING LI, ZHITAO FAN, HUI JI, AND ZUOWEI SHEN Abstract. In electron microscopy, 3D reconstruction is one key component in many computer- ized techniques for solving 3D structures of large protein assemblies using electron microscopy

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

    E-print Network

    Moses, Elisha

    Scanning electron microscopy of cells and tissues under fully hydrated conditions Stephan Thiberge) A capability for scanning electron microscopy of wet biological specimens is presented. A membrane resolution of electron microscopy. The resolution of low-contrast materials is 100 nm, whereas in high

  19. Geometric Analysis of 3D Electron Microscopy Data Ullrich Kthe, Bjrn Andres, Thorben Krger, Fred Hamprecht

    E-print Network

    Hamprecht, Fred A.

    Geometric Analysis of 3D Electron Microscopy Data Ullrich Köthe, Björn Andres, Thorben Kröger, Fred pipeline for the segmentation and analysis of 3-dimensional electron microscopy data. Considerable problems in science. High-resolution 3-dimensional electron microscopy of brain tissue is an important tool

  20. REPRESENTATION THEORETIC PATTERNS IN THREE DIMENSIONAL CRYO-ELECTRON MICROSCOPY III -

    E-print Network

    Gurevich, Shamgar

    REPRESENTATION THEORETIC PATTERNS IN THREE DIMENSIONAL CRYO-ELECTRON MICROSCOPY III - PRESENCE-dimensional structure determination of large biological molecules from cryo-electron microscopy pro- jection images and function of the ribosome. Cryo-electron microscopy (cryo-EM for short) is a promising approach to three

  1. In situ transmission electron microscopy of electrochemical lithiation, delithiation and deformation of individual

    E-print Network

    Chen, Sow-Hsin

    In situ transmission electron microscopy of electrochemical lithiation, delithiation of Physics and Technology, Center for Electron Microscopy and MOE Key Laboratory of Artificial Micro A C T We report an in situ transmission electron microscopy study of the electrochemical behav- ior

  2. AUTOMATED CELL NUCLEUS DETECTION FOR LARGE-VOLUME ELECTRON MICROSCOPY OF NEURAL TISSUE

    E-print Network

    Hamprecht, Fred A.

    AUTOMATED CELL NUCLEUS DETECTION FOR LARGE-VOLUME ELECTRON MICROSCOPY OF NEURAL TISSUE F. Boray Tek Research, Heidelberg, Germany ABSTRACT Volumetric electron microscopy techniques, such as serial block-face electron microscopy (SBEM), generate massive amounts of image data that are used for reconstructing neu

  3. MultiFit: a web server for fitting multiple protein structures into their electron microscopy

    E-print Network

    Sali, Andrej

    MultiFit: a web server for fitting multiple protein structures into their electron microscopy ABSTRACT Advances in electron microscopy (EM) allow for structure determination of large biological assem their function. Recent advances established electron microscopy as a central technique for studying

  4. Automated multi-model reconstruction from single-particle electron microscopy data

    E-print Network

    Automated multi-model reconstruction from single-particle electron microscopy data Maxim Shatsky a using single-particle electron microscopy. We propose a fully automated, unsupervised method rights reserved. 1. Introduction Single-particle electron microscopy (EM) is routinely used to re- solve

  5. Structural characterization of components of protein assemblies by comparative modeling and electron cryo-microscopy

    E-print Network

    Sali, Andrej

    and electron cryo-microscopy Maya Topf a , Matthew L. Bakerb , Bino Johnc , Wah Chiub , Andrej Salia characterization of protein assemblies by a combination of electron cryo-microscopy (cryoEM) and com- parative: Protein structure prediction; Comparative modeling; Electron cryo-microscopy; Fitting 1. Introduction

  6. Structure of the Blm1020 S Proteasome Complex by Cryo-electron Microscopy.

    E-print Network

    Hill, Chris

    Structure of the Blm10­20 S Proteasome Complex by Cryo-electron Microscopy. Insights author Keywords: Blm10; PA200; proteasome activator; cryo-electron microscopy; three S proteasome. The two ends of the Abbreviations used: cryo-EM, cryo-electron microscopy; WT, wild-type; ORF

  7. Correlative Light-and Electron Microscopy with chemical tags Mario Perkovic a

    E-print Network

    Schuman, Erin M.

    Correlative Light- and Electron Microscopy with chemical tags Mario Perkovic a , Michael Kunz 2014 Accepted 24 March 2014 Available online xxxx Keywords: Correlative electron and light microscopy Electron tomography Adherens junctions a b s t r a c t Correlative microscopy incorporates the specificity

  8. Image formation modeling in cryo-electron microscopy Milos Vulovic a,b

    E-print Network

    Rieger, Bernd

    Image formation modeling in cryo-electron microscopy Milos Vulovic´ a,b , Raimond B.G. Ravelli b of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands b Electron Microscopy Section, Molecular Cell 14 May 2013 Available online xxxx Keywords: Cryo-electron microscopy Phase contrast Amplitude

  9. Image formation modeling in cryo-electron microscopy Milos Vulovic a,b

    E-print Network

    van Vliet, Lucas J.

    Image formation modeling in cryo-electron microscopy Milos Vulovic´ a,b , Raimond B.G. Ravelli b of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands b Electron Microscopy Section, Molecular Cell 14 May 2013 Available online 25 May 2013 Keywords: Cryo-electron microscopy Phase contrast Amplitude

  10. Automated detection of synapses in serial section Transmission Electron Microscopy image stacks

    E-print Network

    Hamprecht, Fred A.

    1 Automated detection of synapses in serial section Transmission Electron Microscopy image stacks neurons as defined by the chemical synapses between them. Electron microscopy (EM) is capable of resolving ion beam scanning electron microscopy (FIB- SEM) [12] offers high resolution, isotropic voxels (5

  11. Evolutionary bidirectional expansion for the tracing of alpha helices in cryo-electron microscopy reconstructions

    E-print Network

    Wriggers, Willy

    Evolutionary bidirectional expansion for the tracing of alpha helices in cryo-electron microscopy a b s t r a c t Cryo-electron microscopy (cryo-EM) enables the imaging of macromolecular complexes. 1. Introduction The continuing progress in the field of cryo-electron microscopy (cryo-EM) due

  12. 3D Scanning Transmission Electron Microscopy for Catalysts: Imaging and Data Analysis

    E-print Network

    Abidi, Mongi A.

    3D Scanning Transmission Electron Microscopy for Catalysts: Imaging and Data Analysis A. Y revolutionized electron microscopy, for the first time allowing direct imaging of sub-angstrom atomic spacings, A.R. Lipini, S. M. Travaglini, and S. J. Pennycook, J. Electron Microscopy, 55 (2006) 7. [4] P

  13. Electron Thermal Microscopy Todd Brintlinger,, Yi Qi, Kamal H. Baloch, David Goldhaber-Gordon,| and

    E-print Network

    Electron Thermal Microscopy Todd Brintlinger,, Yi Qi, Kamal H. Baloch,§ David Goldhaber surpass this limit but sacrifice imaging speed.4-15 In the same way that electron microscopy was invented to overcome the resolution limits of light microscopy,16 we here demonstrate that an electron microscope can

  14. DNA Deformations near Charged Surfaces: Electron and Atomic Force Microscopy Views

    E-print Network

    van Vliet, Lucas J.

    DNA Deformations near Charged Surfaces: Electron and Atomic Force Microscopy Views F. G. A. Faas, B permitting visualiza- tion by means of electron microscopy (EM) and atomic force microscopy (AFM). In general the level of expression of genes by virtue of its interaction with regulatory proteins. We use electron (EM

  15. Hygroscopic behavior of NaCl-bearing natural aerosol particles using environmental transmission electron microscopy

    E-print Network

    electron microscopy Matthew E. Wise,1 Trudi A. Semeniuk,1 Roelof Bruintjes,2 Scot T. Martin,3 Lynn M particles using environmental transmission electron microscopy, J. Geophys. Res., 112, D10224, doi:10- ronmental scanning electron microscopy have been used to investigate changes in water content and sizes

  16. A history of scanning electron microscopy developments: Towards ``wet-STEM'' imaging

    E-print Network

    Weeks, Eric R.

    A history of scanning electron microscopy developments: Towards ``wet-STEM'' imaging A. Bogner a ``wet-STEM'' and new developments in environmental scanning electron microscopy (ESEM) allows Elsevier Ltd. All rights reserved. Keywords: Electron microscopy; STEM-in-SEM; Transmission mode; Scattered

  17. Opportunities for electron microscopy in space radiation biology

    SciTech Connect

    Lett, J.T.

    1986-01-01

    Densely ionizing, particulate radiations in outer space are likely to cause to mammalian tissues biological damage that is particularly amenable to examination by the techniques of electron microscopy. This situation arises primarily from the fact that once the density of ionization along the particle track exceeds a certain value, small discrete lesions involving many adjacent cells may be caused in organized tissues. Tissue damage produced by ionization densities below the critical value also afford opportunities for electron microscopic evaluation, as is shown by the damage produced in optic and proximate tissues of the New Zealand white rabbit in terrestrial experiments. Late radiation sequelae in nondividing, or terminally differentiating, tissues, and in stem cell populations, are of special importance in these regards. It is probable that evaluations of the hazards posed to astronauts by galactic particulate radiations during prolonged missions in outer space will not be complete without adequate electron microscopic evaluation of the damage those radiations cause to organized tissues.

  18. 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.

  19. Time resolved electron microscopy for in situ experiments

    SciTech Connect

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

    2014-12-15

    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.

  20. 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

  1. Fast microstructure and phase analyses of nanopowders using combined analysis of transmission electron microscopy scattering patterns.

    PubMed

    Boullay, P; Lutterotti, L; Chateigner, D; Sicard, L

    2014-09-01

    The full quantitative characterization of nanopowders using transmission electron microscopy scattering patterns is shown. This study demonstrates the feasibility of the application of so-called combined analysis, a global approach for phase identification, structure refinement, characterization of anisotropic crystallite sizes and shapes, texture analysis and texture variations with the probed scale, using electron diffraction patterns of TiO2 and Mn3O4 nanocrystal aggregates and platinum films. Electron diffraction pattern misalignments, positioning, and slight changes from pattern to pattern are directly integrated and refined within this approach. The use of a newly developed full-pattern search-match methodology for phase identification of nanopowders and the incorporation of the two-wave dynamical correction for diffraction patterns are also reported and proved to be efficient. PMID:25176993

  2. 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.

  3. 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).

  4. Calibration of Wide-Field Deconvolution Microscopy for Quantitative Fluorescence Imaging

    PubMed Central

    Lee, Ji-Sook; Wee, Tse-Luen (Erika); Brown, Claire M.

    2014-01-01

    Deconvolution enhances contrast in fluorescence microscopy images, especially in low-contrast, high-background wide-field microscope images, improving characterization of features within the sample. Deconvolution can also be combined with other imaging modalities, such as confocal microscopy, and most software programs seek to improve resolution as well as contrast. Quantitative image analyses require instrument calibration and with deconvolution, necessitate that this process itself preserves the relative quantitative relationships between fluorescence intensities. To ensure that the quantitative nature of the data remains unaltered, deconvolution algorithms need to be tested thoroughly. This study investigated whether the deconvolution algorithms in AutoQuant X3 preserve relative quantitative intensity data. InSpeck Green calibration microspheres were prepared for imaging, z-stacks were collected using a wide-field microscope, and the images were deconvolved using the iterative deconvolution algorithms with default settings. Afterwards, the mean intensities and volumes of microspheres in the original and the deconvolved images were measured. Deconvolved data sets showed higher average microsphere intensities and smaller volumes than the original wide-field data sets. In original and deconvolved data sets, intensity means showed linear relationships with the relative microsphere intensities given by the manufacturer. Importantly, upon normalization, the trend lines were found to have similar slopes. In original and deconvolved images, the volumes of the microspheres were quite uniform for all relative microsphere intensities. We were able to show that AutoQuant X3 deconvolution software data are quantitative. In general, the protocol presented can be used to calibrate any fluorescence microscope or image processing and analysis procedure. PMID:24688321

  5. Electron microscopy of the early Caenorhabditis elegans embryo.

    PubMed

    Müller-Reichert, T; Mäntler, J; Srayko, M; O'Toole, E

    2008-05-01

    The early Caenorhabditis elegans embryo is currently a popular model system to study centrosome assembly, kinetochore organization, spindle formation, and cellular polarization. Here, we present and review methods for routine electron microscopy and 3D analysis of the early C. elegans embryo. The first method uses laser-induced chemical fixation to preserve the fine structure of isolated embryos. This approach takes advantage of time-resolved fixation to arrest development at specific stages. The second method uses high-pressure freezing of whole worms followed by freeze-substitution (HPF-FS) for ultrastructural analysis. This technique allows staging of developing early embryos within the worm uterus, and has the advantage of superior sample preservation required for high-resolution 3D reconstruction. The third method uses a correlative approach to stage isolated, single embryos by light microscopy followed by HPF-FS and electron tomography. This procedure combines the advantages of time-resolved fixation and superior ultrastructural preservation by high-pressure freezing and allows a higher throughput electron microscopic analysis. The advantages and disadvantages of these methods for different applications are discussed. PMID:18445160

  6. Resinless section electron microscopy reveals the yeast cytoskeleton.

    PubMed

    Penman, J; Penman, S

    1997-04-15

    The cytoskeleton of Saccharomyces cerevisiae is essentially invisible using conventional microscopy techniques. A similar problem was solved for the mammalian cell cytoskeleton using resinless section electron microscopy, a technique applied here to yeast. In the resinless image, soluble proteins are no longer cloaked by embedding medium and must be removed by selective detergent extraction. In yeast, this requires breaching the cell wall by digesting with Zymolyase sufficiently to allow detergent extraction of the plasma membrane lipids. Gel electropherograms show that the extracted or "soluble" proteins are distinct from the retained or "structural" proteins that presumably comprise the cytoskeleton. These putative cytoskeleton proteins include the major portions of a 43-kDa protein, which is presumably actin, and of proteins in a band appearing at 55 kDa, as well as numerous less abundant, nonactin proteins. Resinless section electron micrographs show a dense, three-dimensional web of anastomosing, polymorphic filaments bounded by the remnant cell wall. Although the filament network is very heterogenous, there appear to be two principal classes of filament diameters-5 nm and 15-20 nm-which may correspond to actin and intermediate filaments, respectively. A large oval region of lower filament density probably corresponds to the vacuole, and an electron dense spheroidal body, 300-500 nm in diameter, is likely the nucleus. The techniques detailed in this report afford new approaches to the study of yeast cytoarchitecture. PMID:9108046

  7. High-resolution electron microscopy of advanced materials

    SciTech Connect

    Mitchell, T.E.; Kung, H.H.; Sickafus, K.E.; Gray, G.T. III; Field, R.D.; Smith, J.F.

    1997-11-01

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

  8. 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.

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

    NASA Astrophysics Data System (ADS)

    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.

    2014-07-01

    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).

  10. Spatial-domain low-coherence quantitative phase microscopy for cancer diagnosis

    NASA Astrophysics Data System (ADS)

    Wang, Pin; Bista, Rajan; Bhargava, Rohit; Brand, Randall E.; Liu, Yang

    2011-03-01

    A novel microscopy technique, spatial-domain low-coherence quantitative phase microscopy (SL-QPM), is proposed to obtain quantitative phase imaging of sub-cellular structures with sub-nanometer sensitivity. This technique utilizes a low spatial-coherence from a thermal light source and produces a speckle-free, nanoscale-sensitive quantitative phase map of scattering objects. With this technique, for the first time to our knowledge, we quantified the refractive index of the cell nuclei on the original unmodified histology specimens. The results show that the average refractive index of the cell nucleus is significantly increased in cells from cancer patients compared to that of the histologically normal cells from healthy patients. More importantly, we demonstrate the superior sensitivity of refractive index of cell nucleus in detecting cancer from histologically normal cells from cancer patients. Because this technique is simple, sensitive, does not require special tissue processing, and can be applied to archived specimens, it can be disseminated to all clinical settings.

  11. 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

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

    PubMed Central

    Heuser, John E.

    2011-01-01

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

  13. Imaging and quantitative data acquisition of biological cell walls with Atomic Force Microscopy and Scanning Acoustic Microscopy

    SciTech Connect

    Tittmann, B. R.; Xi, X.

    2014-09-01

    This chapter demonstrates the feasibility of Atomic Force Microscopy (AFM) and High Frequency Scanning Acoustic Microscopy (HF-SAM) as tools to characterize biological tissues. Both the AFM and the SAM have shown to provide imaging (with different resolution) and quantitative elasticity measuring abilities. Plant cell walls with minimal disturbance and under conditions of their native state have been examined with these two kinds of microscopy. After descriptions of both the SAM and AFM, their special features and the typical sample preparation is discussed. The sample preparation is focused here on epidermal peels of onion scales and celery epidermis cells which were sectioned for the AFM to visualize the inner surface (closest to the plasma membrane) of the outer epidermal wall. The nm-wide cellulose microfibrils orientation and multilayer structure were clearly observed. The microfibril orientation and alignment tend to be more organized in older scales compared with younger scales. The onion epidermis cell wall was also used as a test analog to study cell wall elasticity by the AFM nanoindentation and the SAM V(z) feature. The novelty in this work was to demonstrate the capability of these two techniques to analyze isolated, single layered plant cell walls in their natural state. AFM nanoindentation was also used to probe the effects of Ethylenediaminetetraacetic acid (EDTA), and calcium ion treatment to modify pectin networks in cell walls. The results suggest a significant modulus increase in the calcium ion treatment and a slight decrease in EDTA treatment. To complement the AFM measurements, the HF-SAM was used to obtain the V(z) signatures of the onion epidermis. These measurements were focused on documenting the effect of pectinase enzyme treatment. The results indicate a significant change in the V(z) signature curves with time into the enzyme treatment. Thus AFM and HF-SAM open the door to a systematic nondestructive structure and mechanical property study of complex biological cell walls. A unique feature of this approach is that both microscopes allow the biological samples to be examined in their natural fluid (water) environment.

  14. Transmission electron microscopy study of flea lymph cell thin sections

    NASA Astrophysics Data System (ADS)

    Volkov, Uryi P.; Konnov, Nikolai P.; Novikova, Olga V.

    2002-07-01

    Transmission electron microscopy investigation of thin sections remains the major method of cells inner structure study with high resolution. However, the present-day technique of cells preparation make it impossible to study a number of biological samples, such as very small quantity of lymph cells of little insects. A new technique of cells preparation has been developed in our lab, which allows to obtain a thin sections of ultra small quantity of cells. Structure of lymph cells of flea was investigated by the technique.

  15. Simultaneous orientation and thickness mapping in transmission electron microscopy

    SciTech Connect

    Tyutyunnikov, Dmitry; Özdöl, V. Burak; Koch, Christoph T.

    2014-12-04

    In this paper we introduce an approach for simultaneous thickness and orientation mapping of crystalline samples by means of transmission electron microscopy. We show that local thickness and orientation values can be extracted from experimental dark-field (DF) image data acquired at different specimen tilts. The method has been implemented to automatically acquire the necessary data and then map thickness and crystal orientation for a given region of interest. We have applied this technique to a specimen prepared from a commercial semiconductor device, containing multiple 22 nm technology transistor structures. The performance and limitations of our method are discussed and compared to those of other techniques available.

  16. Correlated cryogenic photoactivated localization microscopy and cryo-electron tomography.

    PubMed

    Chang, Yi-Wei; Chen, Songye; Tocheva, Elitza I; Treuner-Lange, Anke; Löbach, Stephanie; Søgaard-Andersen, Lotte; Jensen, Grant J

    2014-07-01

    Cryo-electron tomography (CET) produces three-dimensional images of cells in a near-native state at macromolecular resolution, but identifying structures of interest can be challenging. Here we describe a correlated cryo-PALM (photoactivated localization microscopy)-CET method for localizing objects within cryo-tomograms to beyond the diffraction limit of the light microscope. Using cryo-PALM-CET, we identified multiple and new conformations of the dynamic type VI secretion system in the crowded interior of Myxococcus xanthus. PMID:24813625

  17. Site-specific labeling of proteins for electron microscopy.

    PubMed

    Dambacher, Corey M; Lander, Gabriel C

    2015-11-01

    Electron microscopy is commonly employed to determine the subunit organization of large macromolecular assemblies. However, the field lacks a robust molecular labeling methodology for unambiguous identification of constituent subunits. We present a strategy that exploits the unique properties of an unnatural amino acid in order to enable site-specific attachment of a single, readily identifiable protein label at any solvent-exposed position on the macromolecular surface. Using this method, we show clear labeling of a subunit within the 26S proteasome lid subcomplex that has not been amenable to labeling by traditional approaches. PMID:26409249

  18. 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

  19. Immunochemistry and electron microscopy of head and neck rhabdomyoma.

    PubMed Central

    Helliwell, T R; Sissons, M C; Stoney, P J; Ashworth, M T

    1988-01-01

    Rhabdomyomas are rare benign tumours originating in skeletal or cardiac muscle. Extracardiac tumours are usually situated in the head and neck. Four cases are presented, three arising in the larynx and the other in the cervical region. All four cases were studied by light and electron microscopy, and in three immunohistochemical staining for myoglobin, desmin, and vimentin was carried out to study the diagnostic features of the lesions and their histogenesis. Images Fig 1 Fig 2 Fig 3 Fig 4 Fig 5 Fig 6 Fig 7 Fig 8 Fig 9 Fig 10 PMID:3056977

  20. Confocal Microscopy for Modeling Electron Microbeam Irradiation of Skin

    SciTech Connect

    Miller, John H.; Chrisler, William B.; Wang, Xihai; Sowa, Marianne B.

    2011-08-01

    For radiation exposures employing targeted sources such as particle microbeams, the deposition of energy and dose will depend on the spatial heterogeneity of the spample. Although cell structural variations are relatively minor for two-dimensional cell cultures, they can vary significantly for fully differential tissues. Employing high-resolution confocal microscopy, we have determined the spatial distribution, size, and shape of epidermal kerantinocyte nuclei for the full-thickness EpiDerm skin model (MatTek, Ashland, VA). Application of these data to claculate the microdosimetry and microdistribution of energy deposition by an electron microbeam is discussed.

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

    NASA Astrophysics Data System (ADS)

    Hooghan, Tejpal Kaur

    Dental amalgams have been used for centuries as major restorative materials for decaying teeth. Amalgams are prepared by mixing alloy particles which contain Ag, Sn, and Cu as the major constituent elements with liquid Hg. The study of microstructure is essential in understanding the setting reactions and improving the properties of amalgams. Until the work reported in this dissertation, optical microscopy (OM), scanning electron microscopy (SEM), and x-ray diffractometry (XRD) were used commonly to analyze amalgam microstructures. No previous systematic transmission electron microscopy (TEM) study has been performed due to sample preparation difficulties and composite structure of dental amalgams. The goal of this research was to carry out detailed microstructural and compositional studies of dental amalgams. This was accomplished using the enhanced spatial resolution of the TEM and its associated microanalytical techniques, namely, scanning transmission electron microscopy (STEM), x-ray energy dispersive spectroscopy (XEDS) and micro-microdiffraction (mumuD). A new method was developed for thinning amalgam samples to electron transparency using the "wedge technique." Velvalloy, a low-Cu amalgam, and Tytin, a high-Cu amalgam, were the two amalgams characterized. Velvalloy is composed of a Agsb2Hgsb3\\ (gammasb1)/HgSnsb{7-9}\\ (gammasb2) matrix surrounding unreacted Agsb3Sn (gamma) particles. In addition, hitherto uncharacterized reaction layers between Agsb3Sn(gamma)/Agsb2Hgsb3\\ (gammasb2)\\ and\\ Agsb2Hgsb3\\ (gammasb1)/HgSnsb{7-9}\\ (gammasb2) were observed and analyzed. An Ag-Hg-Sn (betasb1) phase was clearly identified for the first time. In Tytin, the matrix consists of Agsb2Hgsb3\\ (gammasb1) grains. Fine precipitates of Cusb6Snsb5\\ (etasp') are embedded inside the gammasb1 and at the grain boundaries. These precipitates are responsible for the improved creep resistance of Tytin compared to Velvalloy. The additional Cu has completely eliminated the gammasb2 phase which is the weakest component of amalgams. Ag-Hg-Sn (betasb1) and large grains of Cusb6Snsb5\\ (etasp') are found adjacent to the unreacted alloy particles. Tytin alloy particles contain Cusb3Sn\\ (epsilon) precipitates in a matrix of Agsb3Sn (gamma) and Agsb4Sn\\ (beta). SEM was used to correlate the TEM findings in the context of the general microstructure. The results are in good agreement with those published in the literature. The microstructural details reported here, many of which were not previously available, will help provide insight into the deformation mechanisms of dental amalgams.

  2. Simultaneous orientation and thickness mapping in transmission electron microscopy

    DOE PAGESBeta

    Tyutyunnikov, Dmitry; Özdöl, V. Burak; Koch, Christoph T.

    2014-12-04

    In this paper we introduce an approach for simultaneous thickness and orientation mapping of crystalline samples by means of transmission electron microscopy. We show that local thickness and orientation values can be extracted from experimental dark-field (DF) image data acquired at different specimen tilts. The method has been implemented to automatically acquire the necessary data and then map thickness and crystal orientation for a given region of interest. We have applied this technique to a specimen prepared from a commercial semiconductor device, containing multiple 22 nm technology transistor structures. The performance and limitations of our method are discussed and comparedmore »to those of other techniques available.« less

  3. Interfacing Microfluidics with Negative Stain Transmission Electron Microscopy.

    PubMed

    Mukhitov, Nikita; Spear, John M; Stagg, Scott M; Roper, Michael G

    2016-01-01

    A microfluidic platform is presented for preparing negatively stained grids for use in transmission electron microscopy (EM). The microfluidic device is composed of glass etched with readily fabricated features that facilitate the extraction of the grid poststaining and maintains the integrity of the sample. Utilization of this device simultaneously reduced environmental contamination on the grids and improved the homogeneity of the heavy metal stain needed to enhance visualization of biological specimens as compared to conventionally prepared EM grids. This easy-to-use EM grid preparation device provides the basis for future developments of systems with more integrated features, which will allow for high-throughput and dynamic structural biology studies. PMID:26642355

  4. Measurement of dihedral angles by scanning electron microscopy.

    NASA Technical Reports Server (NTRS)

    Achutaramayya, G.; Scott, W. D.

    1973-01-01

    The extension of Hoover's (1971) technique to the case of dihedral-angle measurement is described. Dihedral angles are often determined by interferometry on thermally grooved grain boundaries to obtain information on relative interfacial energies. In the technique considered the measured angles approach the true angles as the tilt angle approaches 90 deg. It is pointed out that the scanning electron microscopy method provides a means of seeing the real root of a groove at a lateral magnification which is higher than that obtainable with interferometry.

  5. Electron microscopy of a Gd-Ba-Cu-O superconductor

    NASA Technical Reports Server (NTRS)

    Ramesh, R.; Thomas, G.; Meng, R. L.; Hor, P. H.; Chu, C. W.

    1989-01-01

    An electron microscopy study has been carried out to characterize the microstructure of a sintered Gd-Ba-Cu-O superconductor alloy. The GdBa2Cu3O(7-x) phase in the oxygen annealed sample is orthorhombic, while in the vacuum annealed sample it is tetragonal. It is shown that the details of the fine structure in the 001-line zone axis convergent beam patterns can be used to distinguish between the orthorhombic form and the tetragonal form. In addition to this matrix phase, an amorphous phase is frequently observed at the triple grain junctions. Gd-rich inclusions have been observed inside the matrix phase.

  6. Analytical electron microscopy of a hydrated interplanetary dust particle

    NASA Technical Reports Server (NTRS)

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

    1988-01-01

    Properties of a hydrated interplanetary dust particle (IDP), Ames-Dec86-11, were investigated using TEM and analytical electron microscopy. The particle was found to have mineralogy and chondritic composition indicating an absence of direct kinship with known carbonaceous chondrites. The available data on the Ames-Dec86-11 suggest that at least one aqueous alteration event took place in this hydrated IDP, during which fine-grained material, possibly glass, was transformed to smectite. This event appears to be unique to hydrated IDPs.

  7. 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 syndrome (AIDS), namely human immunode#12;ciency virus (HIV), produced by electron microscopic tomography by the HIV Structure Group at the Dept. of Biochemistry, Uppsala University. The algorithms are used

  8. Quantitative phase imaging with molecular sensitivity using photoacoustic microscopy with a miniature ring transducer.

    PubMed

    Sheinfeld, Adi; Eldridge, Will J; Wax, Adam

    2015-08-01

    We present a dual-modality system for both structural and molecular cell imaging based on coregistered quantitative phase imaging (QPI) and photoacoustic microscopy (PAM). The QPI system was based on off-axis holography, whereas the PAM system comprised a sinusoidally modulated optical source for excitation and a narrow-band low profile and low-cost ring ultrasonic transducer for detection. This approach facilitated a simple confocal alignment of the excitation beams of both modalities and the ultrasonic detector. This system was demonstrated by imaging endogenous molecules in red blood cells (RBCs) as well as by imaging exogenous molecular labels on cancer cells using gold nanoparticles (GNPs) functionalized to target epidermal growth factor receptor. QPI provided high resolution imaging of the cellular structures while PAM provided molecular contrast. This dual-modality microscopy method can potentially be implemented as a compact and low cost cellular diagnostic assay. PMID:26263416

  9. Quantitative 3D molecular cutaneous absorption in human skin using label free nonlinear microscopy.

    PubMed

    Chen, Xueqin; Grégoire, Sébastien; Formanek, Florian; Galey, Jean-Baptiste; Rigneault, Hervé

    2015-02-28

    Understanding the penetration mechanisms of drugs into human skin is a key issue in pharmaceutical and cosmetics research. To date, the techniques available for percutaneous penetration of compounds fail to provide a quantitative 3D map of molecular concentration distribution in complex tissues as the detected microscopy images are an intricate combination of concentration distribution and laser beam attenuation upon deep penetration. Here we introduce and validate a novel framework for imaging and reconstructing molecular concentration within the depth of artificial and human skin samples. Our approach combines the use of deuterated molecular compounds together with coherent anti-Stokes Raman scattering spectroscopy and microscopy that permits targeted molecules to be unambiguously discriminated within skin layers. We demonstrate both intercellular and transcellular pathways for different active compounds, together with in-depth concentration profiles reflecting the detailed skin barrier architecture. This method provides an enabling platform for establishing functional activity of topically applied products. PMID:25550155

  10. Quantitative segmentation of fluorescence microscopy images of heterogeneous tissue: Approach for tuning algorithm parameters

    NASA Astrophysics Data System (ADS)

    Mueller, Jenna L.; Harmany, Zachary T.; Mito, Jeffrey K.; Kennedy, Stephanie A.; Kim, Yongbaek; Dodd, Leslie; Geradts, Joseph; Kirsch, David G.; Willett, Rebecca M.; Brown, J. Quincy; Ramanujam, Nimmi

    2013-02-01

    The combination of fluorescent contrast agents with microscopy is a powerful technique to obtain real time images of tissue histology without the need for fixing, sectioning, and staining. The potential of this technology lies in the identification of robust methods for image segmentation and quantitation, particularly in heterogeneous tissues. Our solution is to apply sparse decomposition (SD) to monochrome images of fluorescently-stained microanatomy to segment and quantify distinct tissue types. The clinical utility of our approach is demonstrated by imaging excised margins in a cohort of mice after surgical resection of a sarcoma. Representative images of excised margins were used to optimize the formulation of SD and tune parameters associated with the algorithm. Our results demonstrate that SD is a robust solution that can advance vital fluorescence microscopy as a clinically significant technology.

  11. Quantitative analysis of platelets aggregates in 3D by digital holographic microscopy.

    PubMed

    Boudejltia, Karim Zouaoui; Ribeiro de Sousa, Daniel; Uzureau, Pierrick; Yourassowsky, Catherine; Perez-Morga, David; Courbebaisse, Guy; Chopard, Bastien; Dubois, Frank

    2015-09-01

    Platelet spreading and retraction play a pivotal role in the platelet plugging and the thrombus formation. In routine laboratory, platelet function tests include exhaustive information about the role of the different receptors present at the platelet surface without information on the 3D structure of platelet aggregates. In this work, we develop, a method in Digital Holographic Microscopy (DHM) to characterize the platelet and aggregate 3D shapes using the quantitative phase contrast imaging. This novel method is suited to the study of platelets physiology in clinical practice as well as the development of new drugs. PMID:26417523

  12. Quantitative analysis of platelets aggregates in 3D by digital holographic microscopy

    PubMed Central

    Boudejltia, Karim Zouaoui; Ribeiro de Sousa, Daniel; Uzureau, Pierrick; Yourassowsky, Catherine; Perez-Morga, David; Courbebaisse, Guy; Chopard, Bastien; Dubois, Frank

    2015-01-01

    Platelet spreading and retraction play a pivotal role in the platelet plugging and the thrombus formation. In routine laboratory, platelet function tests include exhaustive information about the role of the different receptors present at the platelet surface without information on the 3D structure of platelet aggregates. In this work, we develop, a method in Digital Holographic Microscopy (DHM) to characterize the platelet and aggregate 3D shapes using the quantitative phase contrast imaging. This novel method is suited to the study of platelets physiology in clinical practice as well as the development of new drugs. PMID:26417523

  13. 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.

  14. Structured illumination diffraction phase microscopy for broadband, sub-diffraction resolution, quantitative phase imaging

    PubMed Central

    Chowdhury, Shwetadwip; Izatt, Joseph A.

    2015-01-01

    Structured illumination microscopy (SIM) is an established technique that allows sub-diffraction resolution imaging by heterodyning high sample frequencies into the system’s passband via structured illumination. However, until now, SIM has been typically used to achieve sub-diffraction resolution for intensity-based imaging. Here, we present a novel optical setup that uses structured illumination with a broadband-light source to obtain noise-reduced, sub-diffraction resolution, quantitative-phase (QPM) imaging of cells. We compare this with a previous work for sub-diffraction QPM imaging via SIM that used a laser source, and was thus still corrupted by coherent noise. PMID:24562266

  15. Quantitative assessment of noise reduction with partial spatial coherence illumination in digital holographic microscopy.

    PubMed

    Dohet-Eraly, Jérôme; Yourassowsky, Catherine; Mallahi, Ahmed El; Dubois, Frank

    2016-01-01

    Improving image quality in digital holographic microscopy is achievable by using partial spatial coherence (PSC) illumination instead of fully coherent illumination. This Letter presents simple theoretical models to quantitatively assess the reduction of noise as a function of both the spatial coherence of the illumination and the defocus distance of the noise source. The first developed model states that the effect of the PSC can be studied by discretizing the field of view in the plane of the noise source. The second model, following a continuous approach, corroborates the discrete model and extends it. Experimental results confirm theoretical expectations. PMID:26696171

  16. Nanoscale nuclear architecture for cancer diagnosis by spatial-domain low-coherence quantitative phase microscopy

    NASA Astrophysics Data System (ADS)

    Wang, Pin; Bista, Rajan K.; Khalbuss, Walid E.; Qiu, Wei; Staton, Kevin D.; Zhang, Lin; Brentnall, Teresa A.; Brand, Randall E.; Liu, Yang

    2011-03-01

    Alterations in nuclear architecture are the hallmark diagnostic characteristic of cancer cells. In this work, we show that the nuclear architectural characteristics quantified by spatial-domain low-coherence quantitative phase microscopy (SL-QPM), is more sensitive for the identification of cancer cells than conventional cytopathology. We demonstrated the importance of nuclear architectural characteristics in both an animal model of intestinal carcinogenesis - APC/Min mouse model and human cytology specimens with colorectal cancer by identifying cancer from cytologically noncancerous appearing cells. The determination of nanoscale nuclear architecture using this simple and practical optical instrument is a significant advance towards cancer diagnosis.

  17. A novel fluorescence imaging technique combining deconvolution microscopy and spectral analysis for quantitative detection of opportunistic pathogens

    SciTech Connect

    Le Puil, Michael; Biggerstaff, John P.; Weidow, B.; Price, Jeffery R; Naser, S.; White, D.C.; Alberte, R.

    2006-01-01

    A novel fluorescence imaging technique based on deconvolution microscopy and spectral analysis is presented here as an alternative to confocal laser scanning microscopy. It allowed rapid, specific and simultaneous identification of five major opportunistic pathogens, relevant for public health, in suspension and provided quantitative results.

  18. Atomic resolution electron microscopy of small metal clusters

    NASA Astrophysics Data System (ADS)

    Bovin, J.-O.; Malm, J.-O.

    1991-03-01

    Atomic resolution imaging of cluster structures has been performed with high resolution transmission electron microscopy (HRTEM). Metal particles of the sizes 1 nanometer to tens of nanometers have been surface profile imaged on different supports; like zeolites, cordierite and amorphous carbon. It is shown that organic ligands in Schmid-clusters coordinated to the metal surface are desorbed or destroyed by the electron beam. Dynamic events on the surfaces and in the bulk of small metal particles have been recorded for small crystals of Au, Pt, Rh and Pb and can be classified under three headings; The smaller the crystals are the faster rearrangements of the crystal structure; “clouds” of atoms existing outside some surfaces are involved in extensive structural rearrangements of the surface or crystal surface growth; localized atom hopping on surfaces during crystal growth and desorption also occurs.

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

    SciTech Connect

    Dahmen, Tim; Baudoin, Jean-Pierre G; Lupini, Andrew R; Kubel, Christian; Slusallek, Phillip; De Jonge, Niels

    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.

  20. Cryogenic electron microscopy and single-particle analysis.

    PubMed

    Elmlund, Dominika; Elmlund, Hans

    2015-01-01

    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

  1. Scanning moiré fringe imaging by scanning transmission electron microscopy.

    PubMed

    Su, Dong; Zhu, Yimei

    2010-02-01

    A type of artificial contrast found in annular dark-field imaging is generated by spatial interference between the scanning grating of the electron beam and the specimen atomic lattice. The contrast is analogous to moiré fringes observed in conventional transmission electron microscopy. We propose using this scanning interference for retrieving information about the atomic lattice structure at medium magnifications. Compared with the STEM atomic imaging at high magnifications, this approach might have several advantages including easy observation of lattice discontinuities and reduction of image degradation from carbon contamination and beam damage. Application of the technique to reveal the Burgers vector of misfit dislocations at the interface of epitaxial films is demonstrated and its potential for studying strain fields is discussed. PMID:20006440

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

    PubMed Central

    Lorenz, Ulrich J.; Zewail, Ahmed H.

    2013-01-01

    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

  3. Four-dimensional ultrafast electron microscopy of phase transitions

    PubMed Central

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

    2006-01-01

    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

  4. Theory and application of scanning electron acoustic microscopy

    NASA Technical Reports Server (NTRS)

    Cantrell, John H.; Qian, Menglu; Chen, Ruiyi; Yost, William T.

    1992-01-01

    A three-dimensional theoretical model based on the application of the thermal conduction and Navier equations to a chopped electron beam incident on a disk specimen is used to obtain the particle displacement field in the specimen. The results lead to a consideration of the signal generation, spatial resolution, and contrast mechanisms in scanning electron acoustic microscopy (SEAM). The model suggests that the time-variant heat source produced by the beam chopping generates driving source, thermal wave, and acoustic wave displacements simultaneously in the specimen. Evidence of the correctness of the prediction is obtained from the mathematically similar problem of pulsed laser light injection into a tank of water. High speed Schlieren photographs taken following laser injection show the simultaneous evolution of thermal and acoustic waveforms. Examples of contrast reversal, stress-induced contrast, and acoustic zone contrast and resolution with SEAM are presented and explained in terms of the model features.

  5. Accurate single-shot quantitative phase imaging of biological specimens with telecentric digital holographic microscopy.

    PubMed

    Doblas, Ana; Sánchez-Ortiga, Emilio; Martínez-Corral, Manuel; Saavedra, Genaro; Garcia-Sucerquia, Jorge

    2014-04-01

    The advantages of using a telecentric imaging system in digital holographic microscopy (DHM) to study biological specimens are highlighted. To this end, the performances of nontelecentric DHM and telecentric DHM are evaluated from the quantitative phase imaging (QPI) point of view. The evaluated stability of the microscope allows single-shot QPI in DHM by using telecentric imaging systems. Quantitative phase maps of a section of the head of the drosophila melanogaster fly and of red blood cells are obtained via single-shot DHM with no numerical postprocessing. With these maps we show that the use of telecentric DHM provides larger field of view for a given magnification and permits more accurate QPI measurements with less number of computational operations. PMID:24781590

  6. A national facility for biological cryo-electron microscopy

    PubMed Central

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

    2015-01-01

    Three-dimensional electron microscopy is an enormously powerful tool for structural biologists. It is now able to provide an understanding of the molecular machinery of cells, disease processes and the actions of pathogenic organisms from atomic detail through to the cellular context. However, cutting-edge research in this field requires very substantial resources for equipment, infrastructure and expertise. Here, a brief overview is provided of the plans for a UK national three-dimensional electron-microscopy facility for integrated structural biology to enable internationally leading research on the machinery of life. State-of-the-art equipment operated with expert support will be provided, optimized for both atomic-level single-particle analysis of purified macromolecules and complexes and for tomography of cell sections. The access to and organization of the facility will be modelled on the highly successful macromolecular crystallography (MX) synchrotron beamlines, and will be embedded at the Diamond Light Source, facilitating the development of user-friendly workflows providing near-real-time experimental feedback. PMID:25615867

  7. Collaborative Computational Project for Electron cryo-Microscopy

    SciTech Connect

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

    2015-01-01

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

  8. 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

  9. Frontiers of in situ electron microscopy

    SciTech Connect

    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 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.

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

    SciTech Connect

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

    2011-01-01

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

  11. Dynamic analysis of pathogen-infected host cells using quantitative phase microscopy

    NASA Astrophysics Data System (ADS)

    Lee, Seungrag; Kim, Young Ran; Lee, Ji Yong; Rhee, Joon Haeng; Park, Chang-Soo; Kim, Dug Young

    2011-03-01

    We present the real-time quantitative analysis of Vibrio vulnificus-infected host cells using quantitative phase microscopy (QPM) based on interferometric techniques. This provides the ability to retrieve the phase or optical path-length distribution over the cell with nanometer path-length sensitivity from a single interferogram image. We have used QPM to study dynamic cell morphologic changes and to noninvasively quantify the cell volumes of rat basophilic leukemia RBL-2H3 cells infected with V. vulnificus strains: wild type (MO6-24/O) and RtxA1 toxin mutant (CMM770). During the process of V. vulnificus infection in RBL-2H3 cells, the dynamic changes of quantitative phase images, cell volumes, and areas were observed in real time using QPM. In contrast, dramatic changes were not detected in RBL-2H3 cells infected with the noncytotoxic RtxA1 toxin mutant. The results showed good correlation between QPM analysis and biochemical assays, such as lactate dehydrogenase assay or ?-hexosaminidase release assay. We suggest that QPM is a powerful quantitative method to study the dynamic process of host cells infected with pathogens in a noninvasive manner.

  12. Quantitative imaging of cell dynamics in mouse embryos using light-sheet microscopy

    PubMed Central

    Udan, Ryan S.; Piazza, Victor G.; Hsu, Chih-wei; Hadjantonakis, Anna-Katerina; Dickinson, Mary E.

    2014-01-01

    Single/selective-plane illumination, or light-sheet, systems offer several advantages over other fluorescence microscopy methods for live, 3D microscopy. These systems are valuable for studying embryonic development in several animal systems, such as Drosophila, C. elegans and zebrafish. The geometry of the light path in this form of microscopy requires the sample to be accessible from multiple sides and fixed in place so that it can be rotated around a single axis. Popular methods for mounting include hanging the specimen from a pin or embedding it in 1-2% agarose. These methods can be particularly problematic for certain samples, such as post-implantation mouse embryos, that expand significantly in size and are very delicate and sensitive to mounting. To overcome the current limitations and to establish a robust strategy for long-term (24?h) time-lapse imaging of E6.5-8.5 mouse embryos with light-sheet microscopy, we developed and tested a method using hollow agarose cylinders designed to accommodate for embryonic growth, yet provide boundaries to minimize tissue drift and enable imaging in multiple orientations. Here, we report the first 24-h time-lapse sequences of post-implantation mouse embryo development with light-sheet microscopy. We demonstrate that light-sheet imaging can provide both quantitative data for tracking changes in morphogenesis and reveal new insights into mouse embryogenesis. Although we have used this approach for imaging mouse embryos, it can be extended to imaging other types of embryos as well as tissue explants. PMID:25344073

  13. Structure determination of clathrin coats to subnanometer resolution by single particle cryo-electron microscopy

    E-print Network

    Harrison, Stephen C.

    , the structures of clathrin lattices have been studied by single particle cryo-electron microscopy, which probed resolution by single particle cryo-electron microscopy. Keywords Clathrin coats; Clathrin cages; Cryo-electronStructure determination of clathrin coats to subnanometer resolution by single particle cryo-electron

  14. Contribution submission to the conference Dresden 2011 In situ transmission electron microscopy of growth processes

    E-print Network

    Dunin-Borkowski, Rafal E.

    Contribution submission to the conference Dresden 2011 In situ transmission electron microscopy Electron Microscopy of Materials;Topical session (AGMM): New Developments in Transmission Electron. Wagner1, Zi-An Li3, Michael Farle3, and Rafal E. Dunin-Borkowski1 -- 1Center for Electron Nanoscopy

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

    PubMed Central

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

    2011-01-01

    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

  16. High resolution quantitative phase imaging in digital holographic microscopy by modulated object illumination with an electrically focusable lens

    NASA Astrophysics Data System (ADS)

    Kemper, Björn; Schubert, Robin; Vollmer, Angelika

    2013-06-01

    In digital holographic microscopy (DHM), scattering patterns that are induced by coherent laser light affect the resolution for the detection of optical path length changes. We present a simple and efficient approach for the reduction of coherent disturbances in quantitative phase imaging in self-interference DHM that is based on amplitude and phase modulation of the sample illumination. The performance of the method for quantitative phase imaging is characterized and the application for quantitative analysis of living cells is illustrated.

  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. Quantitative Electron Tomography of Rubber Composites

    NASA Astrophysics Data System (ADS)

    Staniewicz, Lech; Vaudey, Thomas; Degrandcourt, Christophe; Couty, Marc; Gaboriaud, Fabien; Midgley, Paul

    2014-06-01

    Rubber composite materials have many applications, one example being tyre manufacture. The presence of a filler material in the composite (such as carbon black or silica) causes its mechanical properties to differ in several ways when compared to pure rubber such as viscoelastic behaviour (the Payne effect), increased tensile strength and improved wear resistance. To fully understand these properties, it is necessary to characterise how the filler material is organised on the nanoscale. Using composite materials representative of those found in tyres, this work illustrates the use of electron tomography and machine learning methods as tools to describe the percolation behaviour of the filler; in this case, we focus on the largest proportion of particles absorbed into one single object as a function of particle spacing.

  19. 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

  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. Charging in scanning electron microscopy "from inside and outside".

    PubMed

    Cazaux, Jacques

    2004-01-01

    This paper is an attempt to analyse most of the complicated mechanisms involved in charging and discharging of insulators investigated by scanning electron microscopy (SEM). Fundamental concepts on the secondary electron emission (SEE) yield from insulators combined with electrostatics arguments permit to reconsider, first, the widespread opinion following which charging is minimised when the incident beam energy E0 is chosen to be equal to the critical energy E(o)2, where the nominal total yield delta(o) + eta(o) = 1. For bare insulators submitted to a defocused irradiation, it is suggested here that the critical energy under permanent irradiation EC2 corresponds to a range of primary electrons, R, and nearly equals the maximum escape depth of the secondary electrons, r. This suggestion is supported by a comparison between published data of the SEE yield delta(o) of insulators (short pulse experiments) and experimental results obtained from a permanent irradiation for EC2. New SEE effects are also predicted at the early beginning of irradiation when finely focused probes are used. Practical considerations are also developed, with specific attention given to the role of a contamination layer where a negative charging may occur at any beam energy. The role of the various time constants involved in charging and discharging is also investigated, with special attention given to the dielectric time constant, which explains the dose rate-dependent effects on the effective landing energy in the steady state. Numerical applications permit to give orders of magnitude of various effects, and several other practical consequences are deduced and illustrated. Some new mechanisms for the contrast reversal during irradiation or with the change of the primary electron (PE) energy are also suggested. PMID:15473270

  2. Immune electron microscopy of avian infectious bronchitis virus serotypes.

    PubMed Central

    Odenwald, W F; Johnson, R B; Marquardt, W W; Hetrick, F M

    1978-01-01

    An immune electron microscopy agglutination technique in which emphasis is placed upon the importance of antigen-antibody equivalence has been developed as a possible method for the serotyping of avian infectious bronchitis viruses. The Connecticut and Massachusetts 41 serotypes were used as a model system. Stock virus concentrations were standardized by physical particle counts of virions sedimented directly onto electron microscope specimen grids. Suspensions containing approximately 150 virions per grid square were allowed to react with dilutions of homologous and heterologous antisera. Virions in these constant virus-variable serum mixtures were sedimented directly onto electron microscope specimen grids, and the relative degree of aggregation per grid was determined from the mean percent aggregation of five randomly selected grid squares. In homologous assays, regions of relative antibody excess, of equivalence, and of relative antigen excess were clearly evident. At equivalence, the mean percent aggregation was significantly higher than in the regions of relative antibody or antigen excess. In the heterologous systems, the degree of aggregation differed little from that of the virus controls containing no antiserum. Images PMID:209056

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

    SciTech Connect

    De Jonge, Niels; Sougrat, Rachid; Northan, Brian; Pennycook, Stephen J

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

    PubMed

    de Jonge, Niels; Sougrat, Rachid; Northan, Brian M; Pennycook, Stephen J

    2010-02-01

    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 dataset. The resolution of the reconstruction is comparable to that achieved by tilt-series transmission electron microscopy. However, the focal-series method does not require mechanical tilting and is therefore much faster. 3D STEM images were also recorded of the Golgi ribbon in conventional thin sections containing 3T3 cells with a comparable axial resolution in the deconvolved dataset. PMID:20082729

  5. A transmission electron microscopy study of presolar hibonite

    E-print Network

    Zega, Thomas J; Nittler, Larry R; Stroud, Rhonda M

    2011-01-01

    We report isotopic and microstructural data on five presolar hibonite grains 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. 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, 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 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 superno...

  6. 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

  7. Quantitative confocal fluorescence microscopy of dynamic processes by multifocal fluorescence correlation spectroscopy

    NASA Astrophysics Data System (ADS)

    Krmpot, Aleksandar J.; Nikoli?, Stanko N.; Vitali, Marco; Papadopoulos, Dimitrios K.; Oasa, Sho; Thyberg, Per; Tisa, Simone; Kinjo, Masataka; Nilsson, Lennart; Gehring, Walter J.; Terenius, Lars; Rigler, Rudolf; Vukojevic, Vladana

    2015-07-01

    Quantitative confocal fluorescence microscopy imaging without scanning is developed for the study of fast dynamical processes. The method relies on the use of massively parallel Fluorescence Correlation Spectroscopy (mpFCS). Simultaneous excitation of fluorescent molecules across the specimen is achieved by passing a single laser beam through a Diffractive Optical Element (DOE) to generate a quadratic illumination matrix of 32×32 light sources. Fluorescence from 1024 illuminated spots is detected in a confocal arrangement by a matching matrix detector consisting of the same number of single-photon avalanche photodiodes (SPADs). Software was developed for data acquisition and fast autoand cross-correlation analysis by parallel signal processing using a Graphic Processing Unit (GPU). Instrumental performance was assessed using a conventional single-beam FCS instrument as a reference. Versatility of the approach for application in biomedical research was evaluated using ex vivo salivary glands from Drosophila third instar larvae expressing a fluorescently-tagged transcription factor Sex Combs Reduced (Scr) and live PC12 cells stably expressing the fluorescently tagged mu-opioid receptor (MOPeGFP). We show that quantitative mapping of local concentration and mobility of transcription factor molecules across the specimen can be achieved using this approach, which paves the way for future quantitative characterization of dynamical reaction-diffusion landscapes across live cells/tissue with a submillisecond temporal resolution (presently 21 ?s/frame) and single-molecule sensitivity.

  8. Three-dimensional quantitative phase imaging via tomographic deconvolution phase microscopy.

    PubMed

    Jenkins, Micah H; Gaylord, Thomas K

    2015-11-01

    The field of three-dimensional quantitative phase imaging (3D QPI) is expanding rapidly with applications in biological, medical, and industrial research, development, diagnostics, and metrology. Much of this research has centered on developing optical diffraction tomography (ODT) for biomedical applications. In addition to technical difficulties associated with coherent noise, ODT is not congruous with optical microscopy utilizing partially coherent light, which is used in most biomedical laboratories. Thus, ODT solutions have, for the most part, been limited to customized optomechanical systems which would be relatively expensive to implement on a wide scale. In the present work, a new phase reconstruction method, called tomographic deconvolution phase microscopy (TDPM), is described which makes use of commercial microscopy hardware in realizing 3D QPI. TDPM is analogous to methods used in deconvolution microscopy which improve spatial resolution and 3D-localization accuracy of fluorescence micrographs by combining multiple through-focal scans which are deconvolved by the system point spread function. TDPM is based on the 3D weak object transfer function theory which is shown here to be capable of imaging "nonweak" phase objects with large phase excursions. TDPM requires no phase unwrapping and recovers the entire object spectrum via object rotation, mitigating the need to fill in the "missing cone" of spatial frequencies algorithmically as in limited-angle ODT. In the present work, TDPM is demonstrated using optical fibers, including single-mode, polarization-maintaining, and photonic-crystal fibers as well as an azimuthally varying CO2-laser-induced long-period fiber grating period as test phase objects. PMID:26560576

  9. Low-temperature scanning electron microscopy in biology.

    PubMed

    Read, N D; Jeffree, C E

    1991-01-01

    A review of low-temperature scanning electron microscopy (LTSEM) with regard to preparation protocols, specimen preservation, experimental approaches, and high-resolution studies, is provided. Preparative procedures are described and recent developments in methodologies highlighted. It is now well established that LTSEM, for most biological specimens, provides superior specimen preservation than does ambient-temperature SEM. This is because frozen-hydrated samples retain most or all of their water, are rapidly immobilized and stabilized by cryofixation, and are not exposed to chemical modification or solvent extraction. Nevertheless, artefacts in LTSEM are common and most arise because frozen-hydrated specimens contain water. LTSEM can be used as a powerful experimental tool. Advantages of employing LTSEM for this purpose and ways in which it can be used for novel experimentation are discussed. The most exciting development in recent years has been high-resolution LTSEM. The advantages, problems and requirements for this approach are defined. PMID:2016738

  10. Nanocrystal size distribution analysis from transmission electron microscopy images.

    PubMed

    van Sebille, Martijn; van der Maaten, Laurens J P; Xie, Ling; Jarolimek, Karol; Santbergen, Rudi; van Swaaij, René A C M M; Leifer, Klaus; Zeman, Miro

    2015-12-28

    We propose a method, with minimal bias caused by user input, to quickly detect and measure the nanocrystal size distribution from transmission electron microscopy (TEM) images using a combination of Laplacian of Gaussian filters and non-maximum suppression. We demonstrate the proposed method on bright-field TEM images of an a-SiC:H sample containing embedded silicon nanocrystals with varying magnifications and we compare the accuracy and speed with size distributions obtained by manual measurements, a thresholding method and PEBBLES. Finally, we analytically consider the error induced by slicing nanocrystals during TEM sample preparation on the measured nanocrystal size distribution and formulate an equation to correct this effect. PMID:26593390

  11. Electron microscopy of gallium nitride growth on polycrystalline diamond

    NASA Astrophysics Data System (ADS)

    Webster, R. F.; Cherns, D.; Kuball, M.; Jiang, Q.; Allsopp, D.

    2015-11-01

    Transmission and scanning electron microscopy were used to examine the growth of gallium nitride (GaN) on polycrystalline diamond substrates grown by metalorganic vapour phase epitaxy with a low-temperature aluminium nitride (AlN) nucleation layer. Growth on unmasked substrates was in the (0001) orientation with threading dislocation densities ?7 × 109 cm-2. An epitaxial layer overgrowth technique was used to reduce the dislocation densities further, by depositing silicon nitride stripes on the surface and etching the unmasked regions down to the diamond substrate. A re-growth was then performed on the exposed side walls of the original GaN growth, reducing the threading dislocation density in the overgrown regions by two orders of magnitude. The resulting microstructures and the mechanisms of dislocation reduction are discussed.

  12. WATERSHED MERGE FOREST CLASSIFICATION FOR ELECTRON MICROSCOPY IMAGE STACK SEGMENTATION

    PubMed Central

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

    2014-01-01

    Automated electron microscopy (EM) image analysis techniques can be tremendously helpful for connectomics research. In this paper, we extend our previous work [1] and propose a fully automatic method to utilize inter-section information for intra-section neuron segmentation of EM image stacks. A watershed merge forest is built via the watershed transform with each tree representing the region merging hierarchy of one 2D section in the stack. A section classifier is learned to identify the most likely region correspondence between adjacent sections. The inter-section information from such correspondence is incorporated to update the potentials of tree nodes. We resolve the merge forest using these potentials together with consistency constraints to acquire the final segmentation of the whole stack. We demonstrate that our method leads to notable segmentation accuracy improvement by experimenting with two types of EM image data sets. PMID:25484631

  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. Collaborative Computational Project for Electron cryo-Microscopy

    PubMed Central

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

    2015-01-01

    The Collaborative Computational Project for Electron cryo-Microscopy (CCP-EM) 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. PMID:25615866

  15. A primer to single-particle cryo-electron microscopy.

    PubMed

    Cheng, Yifan; Grigorieff, Nikolaus; Penczek, Pawel A; Walz, Thomas

    2015-04-23

    Cryo-electron microscopy (cryo-EM) of single-particle specimens is used to determine the structure of proteins and macromolecular complexes without the need for crystals. Recent advances in detector technology and software algorithms now allow images of unprecedented quality to be recorded and structures to be determined at near-atomic resolution. However, compared with X-ray crystallography, cryo-EM is a young technique with distinct challenges. This primer explains the different steps and considerations involved in structure determination by single-particle cryo-EM to provide an overview for scientists wishing to understand more about this technique and the interpretation of data obtained with it, as well as a starting guide for new practitioners. PMID:25910204

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

    PubMed

    Koeck, Philip J B

    2016-02-01

    Recently annular dark field (ADF) transmission electron microscopy (TEM) has been advocated as a means of recording images of biological specimens with better signal to noise ratio (SNR) than regular bright field images. I investigate whether and how such images could be used to determine the three-dimensional structure of proteins given that an ADF aperture with a suitable pass-band can be manufactured and used in practice. I develop an approximate theory of ADF-TEM image formation for weak amplitude and phase objects and test this theory using computer simulations. I also test whether these simulated images can be used to calculate a three-dimensional model of the protein using standard software and discuss problems and possible ways to overcome these. PMID:26656466

  17. 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

  18. 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.

  19. 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

  20. Quantitative electron phase imaging with high sensitivity and an unlimited field of view.

    PubMed

    Maiden, A M; Sarahan, M C; Stagg, M D; Schramm, S M; Humphry, M J

    2015-01-01

    As it passes through a sample, an electron beam scatters, producing an exit wavefront rich in information. A range of material properties, from electric and magnetic field strengths to specimen thickness, strain maps and mean inner potentials, can be extrapolated from its phase and mapped at the nanoscale. Unfortunately, the phase signal is not straightforward to obtain. It is most commonly measured using off-axis electron holography, but this is experimentally challenging, places constraints on the sample and has a limited field of view. Here we report an alternative method that avoids these limitations and is easily implemented on an unmodified transmission electron microscope (TEM) operating in the familiar selected area diffraction mode. We use ptychography, an imaging technique popular amongst the X-ray microscopy community; recent advances in reconstruction algorithms now reveal its potential as a tool for highly sensitive, quantitative electron phase imaging. PMID:26423558

  1. Quantitative electron phase imaging with high sensitivity and an unlimited field of view

    NASA Astrophysics Data System (ADS)

    Maiden, A. M.; Sarahan, M. C.; Stagg, M. D.; Schramm, S. M.; Humphry, M. J.

    2015-10-01

    As it passes through a sample, an electron beam scatters, producing an exit wavefront rich in information. A range of material properties, from electric and magnetic field strengths to specimen thickness, strain maps and mean inner potentials, can be extrapolated from its phase and mapped at the nanoscale. Unfortunately, the phase signal is not straightforward to obtain. It is most commonly measured using off-axis electron holography, but this is experimentally challenging, places constraints on the sample and has a limited field of view. Here we report an alternative method that avoids these limitations and is easily implemented on an unmodified transmission electron microscope (TEM) operating in the familiar selected area diffraction mode. We use ptychography, an imaging technique popular amongst the X-ray microscopy community; recent advances in reconstruction algorithms now reveal its potential as a tool for highly sensitive, quantitative electron phase imaging.

  2. Quantitative electron phase imaging with high sensitivity and an unlimited field of view

    PubMed Central

    Maiden, A. M.; Sarahan, M. C.; Stagg, M. D.; Schramm, S. M.; Humphry, M. J.

    2015-01-01

    As it passes through a sample, an electron beam scatters, producing an exit wavefront rich in information. A range of material properties, from electric and magnetic field strengths to specimen thickness, strain maps and mean inner potentials, can be extrapolated from its phase and mapped at the nanoscale. Unfortunately, the phase signal is not straightforward to obtain. It is most commonly measured using off-axis electron holography, but this is experimentally challenging, places constraints on the sample and has a limited field of view. Here we report an alternative method that avoids these limitations and is easily implemented on an unmodified transmission electron microscope (TEM) operating in the familiar selected area diffraction mode. We use ptychography, an imaging technique popular amongst the X-ray microscopy community; recent advances in reconstruction algorithms now reveal its potential as a tool for highly sensitive, quantitative electron phase imaging. PMID:26423558

  3. ELECTRON MICROSCOPY ANALYSIS OF SILICON ISLANDS AND LINE STRUC-TURES FORMED ON SCREEN-PRINTED AL-DOPED P+

    E-print Network

    ELECTRON MICROSCOPY ANALYSIS OF SILICON ISLANDS AND LINE STRUC- TURES FORMED ON SCREEN-PRINTED AL 50 nm) advanced transmission electron microscopy (TEM), scan- ning electron microscopy (SEM), scanning transmission electron microscopy (STEM) and energy dispersive X-ray analysis (EDX) are combined

  4. Characterization of Catalysts for the Synthesis of Higher Alcohols using Transmission Electron Microscopy

    E-print Network

    Dunin-Borkowski, Rafal E.

    Microscopy L. D. L. Duchstein*, T. W. Hansen, J. B. Wagner, R. E. Dunin-Borkowski Center for Electron in such reactions is poor, resulting in a demand for better catalysts [1]. Transmission electron microscopyCharacterization of Catalysts for the Synthesis of Higher Alcohols using Transmission Electron

  5. An Optimal Policy for Target Localization with Application to Electron Microscopy

    E-print Network

    Fua, Pascal

    An Optimal Policy for Target Localization with Application to Electron Microscopy Raphael Sznitman Optimal Policy for Target Localization with Application to Electron Microscopy framework and explicitly then use this policy in the context of localiz- ing mitochondria in electron microscope im- ages

  6. Optimized conditions for imaging the effects of bonding charge density in electron microscopy

    E-print Network

    Marks, Laurence D.

    Optimized conditions for imaging the effects of bonding charge density in electron microscopy J effects in aberration-corrected high resolution electron microscopy (HREM) images along the [0 1 0 is similarly high for an un-corrected conventional electron microscope, implying an experimental limitation

  7. 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...

  8. Scanning Electron Microscopy of Squid, Loligo peale;: Raw, Cooked, and Frozen Mantle

    E-print Network

    Scanning Electron Microscopy of Squid, Loligo peale;: Raw, Cooked, and Frozen Mantle W. STEVEN scanning electron microscopy (SEM) has not been reported, nor has SEM been used to describe ultrastructural of better transmission electron microscopic techniques, Ward and Wainwright (1972) gave a complete

  9. Developing a denoising filter for electron microscopy and tomography data in the cloud

    E-print Network

    Wriggers, Willy

    REVIEW Developing a denoising filter for electron microscopy and tomography data in the cloud-object image formation of cryo-electron microscopy (cryo-EM) result in extremely high noise levels and low . Supervised classification . Remote collaboration Introduction Three-dimensional (3D) cryogenic Electron

  10. Practical Image Restoration of Thick Biological Specimens Using Multiple Focus Levels in Transmission Electron Microscopy

    E-print Network

    Agard, David

    in Transmission Electron Microscopy Karen F. Han,1 John W. Sedat, and David A. Agard Graduate Group in Biophysics data from thick samples. 1997 Academic Press Key Words: transmission electron microscopy; im- age School, San Francisco, California 94143-0448 Received September 9, 1997 Three-dimensional electron

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

    E-print Network

    Bennett, Steven D.

    Energy levels of few-electron quantum dots imaged and characterized by atomic force microscopy. nanoelectronics single-electron charging shell structure electrostatic force microscopy The ability to confine, 2009) Strong confinement of charges in few-electron systems such as in atoms, molecules, and quantum

  12. Magnetofossil spike during the Paleocene-Eocene thermal maximum: Ferromagnetic resonance, rock magnetic, and electron microscopy

    E-print Network

    Kirschvink, Joseph L.

    magnetic, and electron microscopy evidence from Ancora, New Jersey, United States Robert E. Kopp,1: Ferromagnetic resonance, rock magnetic, and electron microscopy evidence from Ancora, New Jersey, United States), isothermal and anhysteretic remanent magnetization, first-order reversal curve, and transmission electron

  13. An apparatus for imaging liquids, cells, and other wet samples in the scanning electron microscopy

    E-print Network

    Moses, Elisha

    An apparatus for imaging liquids, cells, and other wet samples in the scanning electron microscopy a technique of scanning electron microscopy that is adapted to the study of wet samples. The wet environment is protected in a small chamber enclosed by a membrane, which is thin enough for energetic electrons to go

  14. Transmission electron microscopy of oxide development on 9Cr ODS steel in supercritical water

    E-print Network

    Motta, Arthur T.

    Transmission electron microscopy of oxide development on 9Cr ODS steel in supercritical water A examined using cross-sectional transmission electron microscopy. A focused ion beam in situ lift-out technique was used to produce site-specific samples with electron transparent areas up to 8 lm by 10 lm

  15. 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

  16. Atomic-resolution electron energy loss spectroscopy imaging in aberration corrected scanning transmission electron microscopy.

    PubMed

    Allen, L J; Findlay, S D; Lupini, A R; Oxley, M P; Pennycook, S J

    2003-09-01

    The "delocalization" of inelastic scattering is an important issue for the ultimate spatial resolution of innershell spectroscopy in the electron microscope. It is demonstrated in a nonlocal model for electron energy loss spectroscopy (EELS) that delocalization of scanning transmission electron microscopy (STEM) images for single, isolated atoms is primarily determined by the width of the probe, even for light atoms. We present experimental data and theoretical simulations for Ti L-shell EELS in a [100] SrTiO3 crystal showing that, in this case, delocalization is not significantly increased by dynamical propagation. Issues relating to the use of aberration correctors in the STEM geometry are discussed. PMID:14525490

  17. Transmission Electron Microscopy Investigations of Domain Wall and Dislocation Interactions

    NASA Astrophysics Data System (ADS)

    Lindquist, A. K.; Feinberg, J. M.; Harrison, R. J.; Newell, A. J.

    2013-12-01

    The effects of dislocations on domain wall motion in magnetite are important to a variety of paleomagnetic applications. Here we directly image these effects using a transmission electron microscope. Four samples were cut from a single, fully oriented crystal of magnetite. These magnetites were deformed in the dislocation glide regime using a one-atmosphere rig at varying temperatures and pressures to create dislocations. In one dislocation-rich sample, traditional and Lorentz-mode transmission electron microscopy was used to investigate the crystallographic nature of the dislocations and to observe their interactions with domain walls. Dislocations were primarily, though not exclusively, found in the {111} planes with Burgers vectors in the expected <110> directions. Domain wall pinning at dislocations was recorded as the sample was tilted within the microscope in the presence of a 16.8 mT axial field. This allowed us to experimentally determine the microcoercivity, which was 0.5 mT, on average. FORC diagram measurements from all samples showed typical multidomain coercivity distributions, with a central higher coercivity ridge extending out to between 5 and 20 mT. The microcoercivity measurements are in good agreement with theoretical models for domain wall pinning at a dislocation, and the bulk coercivity measurements are in good agreement with models for domain wall pinning at larger dislocation populations.

  18. The characterization of nanoparticles using analytical electron microscopy

    NASA Astrophysics Data System (ADS)

    Hill, Whitney B.

    2011-06-01

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

  19. Nanomusical systems visualized and controlled in 4D electron microscopy.

    PubMed

    Baskin, J Spencer; Park, Hyun Soon; Zewail, Ahmed H

    2011-05-11

    Nanomusical systems, nanoharp and nanopiano, fabricated as arrays of cantilevers by focused ion beam milling of a layered Ni/Ti/Si(3)N(4) thin film, have been investigated in 4D electron microscopy. With the imaging and selective femtosecond and nanosecond control combinations, full characterization of the amplitude and phase of the resonant response of a particular cantilever relative to the optical pulse train was possible. Using a high repetition rate, low energy optical pulse train for selective, resonant excitation, coupled with pulsed and steady-state electron imaging for visualization in space and time, both the amplitude on the nanoscale and resonance of motion on the megahertz scale were resolved for these systems. Tilting of the specimen allowed in-plane and out-of-plane cantilever bending and cantilever torsional motions to be identified in stroboscopic measurements of impulsively induced free vibration. Finally, the transient, as opposed to steady state, thermostat effect was observed for the layered nanocantilevers, with a sufficiently sensitive response to demonstrate suitability for in situ use in thin-film temperature measurements requiring resolutions of <10 K and 10 ?m on time scales here mechanically limited to microseconds and potentially at shorter times. PMID:21513332

  20. 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).

  1. High Resolution Transmission Electron Microscopy (HRTEM) of nanophase ferric oxides

    NASA Technical Reports Server (NTRS)

    Golden, D. C.; Morris, R. V.; Ming, D. W.; Lauer, H. V., Jr.

    1994-01-01

    Iron oxide minerals are the prime candidates for Fe(III) signatures in remotely sensed Martian surface spectra. Magnetic, Mossbauer, and reflectance spectroscopy have been carried out in the laboratory in order to understand the mineralogical nature of Martian analog ferric oxide minerals of submicron or nanometer size range. Out of the iron oxide minerals studied, nanometer sized ferric oxides are promising candidates for possible Martian spectral analogs. 'Nanophase ferric oxide (np-Ox)' is a generic term for ferric oxide/oxihydroxide particles having nanoscale (less than 10 nm) particle dimensions. Ferrihydrite, superparamagnetic particles of hematite, maghemite and goethite, and nanometer sized particles of inherently paramagnetic lepidocrocite are all examples of nanophase ferric oxides. np-Ox particles in general do not give X-ray diffraction (XRD) patterns with well defined peaks and would often be classified as X-ray amorphous. Therefore, different np-Oxs preparations should be characterized using a more sensitive technique e.g., high resolution transmission electron microscopy (HRTEM). The purpose of this study is to report the particle size, morphology and crystalline order, of five np-Ox samples by HRTEM imaging and electron diffraction (ED).

  2. 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.

  3. Quantitative Characterization of Biological Liquids for Third-Harmonic Generation Microscopy

    PubMed Central

    Débarre, Delphine; Beaurepaire, Emmanuel

    2007-01-01

    Third-harmonic generation (THG) microscopy provides images of unstained biological samples based on spatial variations in third-order nonlinear susceptibility, refractive index, and dispersion. In this study, we establish quantitative values for the third-order nonlinear susceptibilities of several solvents (water, ethanol, glycerol), physiological aqueous (ions, amino acids, polypeptides, bovine serum albumin, glucose) and lipid (triglycerides, cholesterol) solutions as a function of solute concentration in the 1.05–1.25 ?m excitation range. We use these data in conjunction with imaging experiments to show that THG imaging with ?1.2 ?m excitation lacks specificity and sensitivity to detect physiological ion concentration changes, and that nonaqueous structures such as lipid bodies provide a more robust source of signal. Finally, we illustrate the impact of index-matching liquids in THG images. These data provide a basis for interpreting biological THG images and for developing additional applications. PMID:17085492

  4. Investigation of shape memory of red blood cells using optical tweezers and quantitative phase microscopy

    NASA Astrophysics Data System (ADS)

    Cardenas, Nelson; Mohanty, Samarendra K.

    2012-03-01

    RBC has been shown to possess shape memory subsequent to shear-induced shape transformation. However, this property of RBC may not be generalized to all kinds of stresses. Here, we report our observation on the action of radiation pressure forces on RBC's shape memory using optical manipulation and quantitative phase microscopy (OMQPM). QPM, based on Mach-Zehnder interferrometry, allowed measurement of dynamic changes of shape of RBC in optical tweezers at different trapping laser powers. In high power near-infrared optical tweezers (>200mW), the RBC was found to deform significantly due to optical forces. Upon removal of the tweezers, hysteresis in recovering its original resting shape was observed. In very high power tweezers or long-term stretching events, shape memory was almost erased. This irreversibility of the deformation may be due to temperature rise or stress-induced phase transformation of lipids in RBC membrane.

  5. 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.

  6. 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

  7. Ultra-high vacuum scanning thermal microscopy for nanometer resolution quantitative thermometry.

    PubMed

    Kim, Kyeongtae; Jeong, Wonho; Lee, Woochul; Reddy, Pramod

    2012-05-22

    Understanding energy dissipation at the nanoscale requires the ability to probe temperature fields with nanometer resolution. Here, we describe an ultra-high vacuum (UHV)-based scanning thermal microscope (SThM) technique that is capable of quantitatively mapping temperature fields with ?15 mK temperature resolution and ?10 nm spatial resolution. In this technique, a custom fabricated atomic force microscope (AFM) cantilever, with a nanoscale Au-Cr thermocouple integrated into the tip of the probe, is used to measure temperature fields of surfaces. Operation in an UHV environment eliminates parasitic heat transport between the tip and the sample enabling quantitative measurement of temperature fields on metal and dielectric surfaces with nanoscale resolution. We demonstrate the capabilities of this technique by directly imaging thermal fields in the vicinity of a 200 nm wide, self-heated, Pt line. Our measurements are in excellent agreement with computational results-unambiguously demonstrating the quantitative capabilities of the technique. UHV-SThM techniques will play an important role in the study of energy dissipation in nanometer-sized electronic and photonic devices and the study of phonon and electron transport at the nanoscale. PMID:22530657

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

    NASA Astrophysics Data System (ADS)

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

    1994-11-01

    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 change in the electrode surface, i.e., the increase in surface roughness was observed during the current flow. The degradation process started from faint dark core parts and propagated into disks with different rates depending on the magnitude of applied voltage. Degraded sites of the Al electrode, which were analyzed as aluminum oxide by Auger electron spectroscopy, protruded into the air on the organic layers. In SEM images of a life-end electrode, discontinuities due to crevasse formation in the organic layers sandwiched by the ITO base and the metal top electrodes were observed in many places. These results confirm that one of the most crucial factors of the degradation process was deformation of metal and organic layers due to heat, gas evolution, and oxidation caused by applied voltage.

  9. Assembly of macromolecular complexes by satisfaction of spatial restraints from electron microscopy images

    E-print Network

    Sali, Andrej

    Assembly of macromolecular complexes by satisfaction of spatial restraints from electron microscopy, and optional restraints from proteomics and chemical cross-linking experiments. The optimization relies

  10. 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 ...

  11. Quantitative evaluation of software packages for single-molecule localization microscopy.

    PubMed

    Sage, Daniel; Kirshner, Hagai; Pengo, Thomas; Stuurman, Nico; Min, Junhong; Manley, Suliana; Unser, Michael

    2015-08-01

    The quality of super-resolution images obtained by single-molecule localization microscopy (SMLM) depends largely on the software used to detect and accurately localize point sources. In this work, we focus on the computational aspects of super-resolution microscopy and present a comprehensive evaluation of localization software packages. Our philosophy is to evaluate each package as a whole, thus maintaining the integrity of the software. We prepared synthetic data that represent three-dimensional structures modeled after biological components, taking excitation parameters, noise sources, point-spread functions and pixelation into account. We then asked developers to run their software on our data; most responded favorably, allowing us to present a broad picture of the methods available. We evaluated their results using quantitative and user-interpretable criteria: detection rate, accuracy, quality of image reconstruction, resolution, software usability and computational resources. These metrics reflect the various tradeoffs of SMLM software packages and help users to choose the software that fits their needs. PMID:26076424

  12. Nanoscale imaging of buried topological defects with quantitative X-ray magnetic microscopy

    NASA Astrophysics Data System (ADS)

    Blanco-Roldán, C.; Quirós, C.; Sorrentino, A.; Hierro-Rodríguez, A.; Álvarez-Prado, L. M.; Valcárcel, R.; Duch, M.; Torras, N.; Esteve, J.; Martín, J. I.; Vélez, M.; Alameda, J. M.; Pereiro, E.; Ferrer, S.

    2015-09-01

    Advances in nanoscale magnetism increasingly require characterization tools providing detailed descriptions of magnetic configurations. Magnetic transmission X-ray microscopy produces element specific magnetic domain images with nanometric lateral resolution in films up to ~100 nm thick. Here we present an imaging method using the angular dependence of magnetic contrast in a series of high resolution transmission X-ray microscopy images to obtain quantitative descriptions of the magnetization (canting angles relative to surface normal and sense). This method is applied to 55-120 nm thick ferromagnetic NdCo5 layers (canting angles between 65° and 22°), and to a NdCo5 film covered with permalloy. Interestingly, permalloy induces a 43° rotation of Co magnetization towards surface normal. Our method allows identifying complex topological defects (merons or half skyrmions) in a NdCo5 film that are only partially replicated by the permalloy overlayer. These results open possibilities for the characterization of deeply buried magnetic topological defects, nanostructures and devices.

  13. Nanoscale imaging of buried topological defects with quantitative X-ray magnetic microscopy

    PubMed Central

    Blanco-Roldán, C.; Quirós, C.; Sorrentino, A.; Hierro-Rodríguez, A.; Álvarez-Prado, L. M.; Valcárcel, R.; Duch, M.; Torras, N.; Esteve, J.; Martín, J. I.; Vélez, M.; Alameda, J. M.; Pereiro, E.; Ferrer, S.

    2015-01-01

    Advances in nanoscale magnetism increasingly require characterization tools providing detailed descriptions of magnetic configurations. Magnetic transmission X-ray microscopy produces element specific magnetic domain images with nanometric lateral resolution in films up to ?100?nm thick. Here we present an imaging method using the angular dependence of magnetic contrast in a series of high resolution transmission X-ray microscopy images to obtain quantitative descriptions of the magnetization (canting angles relative to surface normal and sense). This method is applied to 55–120?nm thick ferromagnetic NdCo5 layers (canting angles between 65° and 22°), and to a NdCo5 film covered with permalloy. Interestingly, permalloy induces a 43° rotation of Co magnetization towards surface normal. Our method allows identifying complex topological defects (merons or ½ skyrmions) in a NdCo5 film that are only partially replicated by the permalloy overlayer. These results open possibilities for the characterization of deeply buried magnetic topological defects, nanostructures and devices. PMID:26337838

  14. Nanoscale imaging of buried topological defects with quantitative X-ray magnetic microscopy.

    PubMed

    Blanco-Roldán, C; Quirós, C; Sorrentino, A; Hierro-Rodríguez, A; Álvarez-Prado, L M; Valcárcel, R; Duch, M; Torras, N; Esteve, J; Martín, J I; Vélez, M; Alameda, J M; Pereiro, E; Ferrer, S

    2015-01-01

    Advances in nanoscale magnetism increasingly require characterization tools providing detailed descriptions of magnetic configurations. Magnetic transmission X-ray microscopy produces element specific magnetic domain images with nanometric lateral resolution in films up to ?100?nm thick. Here we present an imaging method using the angular dependence of magnetic contrast in a series of high resolution transmission X-ray microscopy images to obtain quantitative descriptions of the magnetization (canting angles relative to surface normal and sense). This method is applied to 55-120?nm thick ferromagnetic NdCo5 layers (canting angles between 65° and 22°), and to a NdCo5 film covered with permalloy. Interestingly, permalloy induces a 43° rotation of Co magnetization towards surface normal. Our method allows identifying complex topological defects (merons or ½ skyrmions) in a NdCo5 film that are only partially replicated by the permalloy overlayer. These results open possibilities for the characterization of deeply buried magnetic topological defects, nanostructures and devices. PMID:26337838

  15. Broadband quantitative phase microscopy with extended field of view using off-axis interferometric multiplexing.

    PubMed

    Girshovitz, Pinhas; Frenklach, Irena; Shaked, Natan T

    2015-11-01

    We propose a new portable imaging configuration that can double the field of view (FOV) of existing off-axis interferometric imaging setups, including broadband off-axis interferometers. This configuration is attached at the output port of the off-axis interferometer and optically creates a multiplexed interferogram on the digital camera, which is composed of two off-axis interferograms with straight fringes at orthogonal directions. Each of these interferograms contains a different FOV of the imaged sample. Due to the separation of these two FOVs in the spatial-frequency domain, they can be fully reconstructed separately, while obtaining two complex wavefronts from the sample at once. Since the optically multiplexed off-axis interferogram is recorded by the camera in a single exposure, fast dynamics can be recorded with a doubled imaging area. We used this technique for quantitative phase microscopy of biological samples with extended FOV. We demonstrate attaching the proposed module to a diffractive phase microscopy interferometer, illuminated by a broadband light source. The biological samples used for the experimental demonstrations include microscopic diatom shells, cancer cells, and flowing blood cells. PMID:26440914

  16. Quantitative forecast of relativistic electron flux at geosynchronous orbit based on low-energy electron flux

    E-print Network

    Li, Xinlin

    Quantitative forecast of relativistic electron flux at geosynchronous orbit based on low-energy electron flux Drew L. Turner1,2 and Xinlin Li1,2 Received 27 July 2007; revised 18 December 2007; accepted-energy (tens to hundreds of keV) and high-energy (>1 MeV) electron fluxes measured at geosynchronous orbit has

  17. A general way for quantitative magnetic measurement by transmitted electrons.

    PubMed

    Song, Dongsheng; Li, Gen; Cai, Jianwang; Zhu, Jing

    2016-01-01

    EMCD (electron magnetic circular dichroism) technique opens a new door to explore magnetic properties by transmitted electrons. The recently developed site-specific EMCD technique makes it possible to obtain rich magnetic information from the Fe atoms sited at nonequivalent crystallographic planes in NiFe2O4, however it is based on a critical demand for the crystallographic structure of the testing sample. Here, we have further improved and tested the method for quantitative site-specific magnetic measurement applicable for more complex crystallographic structure by using the effective dynamical diffraction effects (general routine for selecting proper diffraction conditions, making use of the asymmetry of dynamical diffraction for design of experimental geometry and quantitative measurement, etc), and taken yttrium iron garnet (Y3Fe5O12, YIG) with more complex crystallographic structure as an example to demonstrate its applicability. As a result, the intrinsic magnetic circular dichroism signals, spin and orbital magnetic moment of iron with site-specific are quantitatively determined. The method will further promote the development of quantitative magnetic measurement with high spatial resolution by transmitted electrons. PMID:26726959

  18. In vivo imaging and quantitative analysis of zebrafish embryos by digital holographic microscopy

    PubMed Central

    Gao, Jian; Lyon, Joseph A.; Szeto, Daniel P.; Chen, Jun

    2012-01-01

    Digital holographic microscopy (DHM) has been applied extensively to in vitro studies of different living cells. In this paper, we present a novel application of an off-axis DHM system to in vivo study of the development of zebrafish embryos. Even with low magnification microscope objectives, the morphological structures and individual cell types inside developing zebrafish embryos can be clearly observed from reconstructed amplitude images. We further study the dynamic process of blood flow in zebrafish embryos. A calibration routine and post-processing procedures are developed to quantify physiological parameters at different developmental stages. We measure quantitatively the blood flow as well as the heart rate to study the effects of elevated D-glucose (abnormal condition) on circulatory and cardiovascular systems of zebrafish embryos. To enhance our ability to use DHM as a quantitative tool for potential high throughput screening application, the calibration and post-processing algorithms are incorporated into an automated processing software. Our results show that DHM is an excellent non-invasive imaging technique for visualizing the cellular dynamics of organogenesis of zebrafish embryos in vivo. PMID:23082301

  19. 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

  20. Amplitude modulation atomic force microscopy, is acoustic driving in liquid quantitatively reliable?

    NASA Astrophysics Data System (ADS)

    Liu, Fei; Zhao, Cunlu; Mugele, Frieder; van den Ende, Dirk

    2015-09-01

    Measuring quantitative tip-sample interaction forces in dynamic atomic force microscopy in fluids is challenging because of the strong damping of the ambient viscous medium and the fluid-mediated driving forces. This holds in particular for the commonly used acoustic excitation of the cantilever oscillation. Here we present measurements of tip-sample interactions due to conservative DLVO and hydration forces and viscous dissipation forces in aqueous electrolytes using tips with radii varying from typical 20 nm for the DLVO and hydration forces, to 1 ?m for the viscous dissipation. The measurements are analyzed using a simple harmonic oscillator model, continuous beam theory with fluid-mediated excitation and thermal noise spectroscopy (TNS). In all cases consistent conservative forces, deviating less than 40% from each other, are obtained for all three approaches. The DLVO forces are even within 5% of the theoretical expectations for all approaches. Accurate measurements of dissipative forces within 15% of the predictions of macroscopic fluid dynamics require the use of TNS or continuous beam theory including fluid-mediated driving. Taking this into account, acoustic driving in liquid is quantitatively reliable.

  1. Amplitude modulation atomic force microscopy, is acoustic driving in liquid quantitatively reliable?

    PubMed

    Liu, Fei; Zhao, Cunlu; Mugele, Frieder; van den Ende, Dirk

    2015-09-25

    Measuring quantitative tip-sample interaction forces in dynamic atomic force microscopy in fluids is challenging because of the strong damping of the ambient viscous medium and the fluid-mediated driving forces. This holds in particular for the commonly used acoustic excitation of the cantilever oscillation. Here we present measurements of tip-sample interactions due to conservative DLVO and hydration forces and viscous dissipation forces in aqueous electrolytes using tips with radii varying from typical 20 nm for the DLVO and hydration forces, to 1 ?m for the viscous dissipation. The measurements are analyzed using a simple harmonic oscillator model, continuous beam theory with fluid-mediated excitation and thermal noise spectroscopy (TNS). In all cases consistent conservative forces, deviating less than 40% from each other, are obtained for all three approaches. The DLVO forces are even within 5% of the theoretical expectations for all approaches. Accurate measurements of dissipative forces within 15% of the predictions of macroscopic fluid dynamics require the use of TNS or continuous beam theory including fluid-mediated driving. Taking this into account, acoustic driving in liquid is quantitatively reliable. PMID:26335613

  2. Hyperspectral and differential CARS microscopy for quantitative chemical imaging in human adipocytes

    PubMed Central

    Di Napoli, Claudia; Pope, Iestyn; Masia, Francesco; Watson, Peter; Langbein, Wolfgang; Borri, Paola

    2014-01-01

    In this work, we demonstrate the applicability of coherent anti-Stokes Raman scattering (CARS) micro-spectroscopy for quantitative chemical imaging of saturated and unsaturated lipids in human stem-cell derived adipocytes. We compare dual-frequency/differential CARS (D-CARS), which enables rapid imaging and simple data analysis, with broadband hyperspectral CARS microscopy analyzed using an unsupervised phase-retrieval and factorization method recently developed by us for quantitative chemical image analysis. Measurements were taken in the vibrational fingerprint region (1200–2000/cm) and in the CH stretch region (2600–3300/cm) using a home-built CARS set-up which enables hyperspectral imaging with 10/cm resolution via spectral focussing from a single broadband 5 fs Ti:Sa laser source. Through a ratiometric analysis, both D-CARS and phase-retrieved hyperspectral CARS determine the concentration of unsaturated lipids with comparable accuracy in the fingerprint region, while in the CH stretch region D-CARS provides only a qualitative contrast owing to its non-linear behavior. When analyzing hyperspectral CARS images using the blind factorization into susceptibilities and concentrations of chemical components recently demonstrated by us, we are able to determine vol:vol concentrations of different lipid components and spatially resolve inhomogeneities in lipid composition with superior accuracy compared to state-of-the art ratiometric methods. PMID:24877002

  3. 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.

  4. Quantitative chemical imaging and unsupervised analysis using hyperspectral coherent anti-Stokes Raman scattering microscopy.

    PubMed

    Masia, Francesco; Glen, Adam; Stephens, Phil; Borri, Paola; Langbein, Wolfgang

    2013-11-19

    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

  5. Scanning transmission electron microscopy strain measurement from millisecond frames of a direct electron charge coupled device

    SciTech Connect

    Mueller, Knut; Rosenauer, Andreas; Ryll, Henning; Ordavo, Ivan; Ihle, Sebastian; Soltau, Heike; Strueder, Lothar; Volz, Kerstin; Zweck, Josef

    2012-11-19

    A high-speed direct electron detection system is introduced to the field of transmission electron microscopy and applied to strain measurements in semiconductor nanostructures. In particular, a focused electron probe with a diameter of 0.5 nm was scanned over a fourfold quantum layer stack with alternating compressive and tensile strain and diffracted discs have been recorded on a scintillator-free direct electron detector with a frame time of 1 ms. We show that the applied algorithms can accurately detect Bragg beam positions despite a significant point spread each 300 kV electron causes during detection on the scintillator-free camera. For millisecond exposures, we find that strain can be measured with a precision of 1.3 Multiplication-Sign 10{sup -3}, enabling, e.g., strain mapping in a 100 Multiplication-Sign 100 nm{sup 2} region with 0.5 nm resolution in 40 s.

  6. 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.

  7. Automatic detection and morphological delineation of bacteriophages in electron microscopy images.

    PubMed

    Gelzinis, A; Verikas, A; Vaiciukynas, E; Bacauskiene, M; Sulcius, S; Simoliunas, E; Staniulis, J; Paskauskas, R

    2015-09-01

    Automatic detection, recognition and geometric characterization of bacteriophages in electron microscopy images was the main objective of this work. A novel technique, combining phase congruency-based image enhancement, Hough transform-, Radon transform- and open active contours with free boundary conditions-based object detection was developed to detect and recognize the bacteriophages associated with infection and lysis of cyanobacteria Aphanizomenon flos-aquae. A random forest classifier designed to recognize phage capsids provided higher than 99% accuracy, while measurable phage tails were detected and associated with a correct capsid with 81.35% accuracy. Automatically derived morphometric measurements of phage capsids and tails exhibited lower variability than the ones obtained manually. The technique allows performing precise and accurate quantitative (e.g. abundance estimation) and qualitative (e.g. diversity and capsid size) measurements for studying the interactions between host population and different phages that infect the same host. PMID:26164031

  8. Rapid phenotypic analysis of uncoated Drosophila samples with low-vacuum scanning electron microscopy.

    PubMed

    Tardi, Nicholas J; Cook, Martha E; Edwards, Kevin A

    2012-01-01

    Research projects featuring repetitive phenotypic analysis of insects, such as taxonomic studies, quantitative genetics, and mutant screens, could be greatly facilitated by a simpler approach to scanning electron microscopy (SEM). Here, we have applied low-vacuum SEM to wild type and mutant Drosophila and demonstrate that high quality ultrastructure data can be obtained quickly using minimal preparation. Adult flies, frozen live for storage, were mounted on aluminum stubs with carbon cement and directly imaged, with no chemical treatment or sputter coating. The key imaging parameters were identified and optimized, including chamber pressure, beam size, accelerating voltage, working distance and beam exposure. Different optimal conditions were found for eyes, wings, and bristles; in particular, surface features of bristles were obscured at higher accelerating voltages. The chief difficulties were charging, beam damage, and sample movement. We conclude that our optimized protocol is well suited to large-scale ultrastructural phenotypic analysis in insects. PMID:22722327

  9. 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

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

    SciTech Connect

    Brunatova, Tereza; Popelkova, Daniela; Wan, Wei; Oleynikov, Peter; Danis, Stanislav; Zou, Xiaodong; Kuzel, Radomir

    2014-01-15

    The structure of titanate nanotubes (Ti-NTs) was studied by a combination of powder X-ray diffraction (PXRD), electron diffraction and high resolution transmission electron microscopy (HRTEM). Ti-NTs are prepared by hydrothermal treatment of TiO{sub 2} powder. The structure is identified by powder X-ray diffraction as the one based on the structure of H{sub 2}Ti{sub 2}O{sub 5}·H{sub 2}O phase. The same structure is obtained by projected potential from HRTEM through-focus image series. The structure is verified by simulated PXRD pattern with the aid of the Debye formula. The validity of the model is tested by computing Fourier transformation of a single nanotube which is proportional to measured electron diffraction intensities. A good agreement of this calculation with measured precession electron diffraction data is achieved. - Highlights: • Titanate nanotubes were prepared by hydrothermal method. • X-ray powder diffraction indicated their structure based on that of H{sub 2}Ti{sub 2}O{sub 5}·H{sub 2}O. • Structural model was created with the aid of high-resolution electron microscopy. • The model was verified with electron diffraction data. • X-ray powder diffraction pattern was calculated with the aid of the Debye formula.

  11. 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.

  12. Atomic-Resolution 3D Electron Microscopy with Dynamic Diffraction

    SciTech Connect

    O'Keefe, Michael A.; Downing, Kenneth H.; Wenk, Hans-Rudolf; Meisheng, Hu

    2005-02-15

    Achievement of atomic-resolution electron-beam tomography will allow determination of the three-dimensional structure of nanoparticles (and other suitable specimens) at atomic resolution. Three-dimensional reconstructions will yield ''section'' images that resolve atoms overlapped in normal electron microscope images (projections), resolving lighter atoms such as oxygen in the presence of heavier atoms, and atoms that lie on non-lattice sites such as those in non-periodic defect structures. Lower-resolution electron microscope tomography has been used to produce reconstructed 3D images of nanoparticles [1] but extension to atomic resolution is considered not to be straightforward. Accurate three-dimensional reconstruction from two-dimensional projections generally requires that intensity in the series of 2-D images be a monotonic function of the specimen structure (often specimen density, but in our case atomic potential). This condition is not satisfied in electron microscopy when specimens with strong periodicity are tilted close to zone-axis orientation and produce ''anomalous'' image contrast because of strong dynamic diffraction components. Atomic-resolution reconstructions from tilt series containing zone-axis images (with their contrast enhanced by strong dynamical scattering) can be distorted when the stronger zone-axis images overwhelm images obtained in other ''random'' orientations in which atoms do not line up in neat columns. The first demonstrations of 3-D reconstruction to atomic resolution used five zone-axis images from test specimens of staurolite consisting of a mix of light and heavy atoms [2,3]. Initial resolution was to the 1.6{angstrom} Scherzer limit of a JEOL-ARM1000. Later experiments used focal-series reconstruction from 5 to 10 images to produce staurolite images from the ARM1000 with resolution extended beyond the Scherzer limit to 1.38{angstrom} [4,5]. To obtain a representation of the three-dimensional structure, images were obtained in zone-axis projections <100>, <010>, <001>, <101>, <310>, and combined to produce a three-dimensional map of Coulomb potential. Images of specimen sections are much more easily interpreted than projection images such as electron micrographs, reducing the need for techniques such as imaging at sub-Rayleigh resolution [6]. Sections through the 3D staurolite potential show atom positions as density peaks that display streaking from insufficient sampling in direction [1]. Three different specimens of perfect crystal were required to achieve the five projection directions; this makes the technique atomic-resolution electron crystallography rather than atomic-resolution tomography. Nevertheless, our results illustrate that dynamic diffraction need not be a limiting factor in atomic-resolution tomographic reconstruction. We have proposed combining ultra-high (sub-Angstrom) resolution zone-axis images with off-zone images by first using linear reconstruction of the off-zone images while excluding images obtained within a small range of tilts (of the order of 60 milliradian) of any zone-axis orientation [7], since it has been shown that dynamical effects can be mitigated by slight off-axis tilt of the specimen [8]. The (partial) reconstruction would then be used as a model for forward calculation by image simulation [9] in zone-axis directions and the structure refined iteratively to achieve satisfactory fits with the experimental zone-axis data. Another path to atomic-resolution tomography would combine ''zone-axis tomography'' with high-resolution dark-field hollow-cone (DFHC) imaging. Electron diffraction theory indicates that dynamic (multiple) scattering is much reduced under highly-convergent illumination. DFHC TEM is the analog of HAADF STEM, and imaging theory shows that image resolution can be enhanced under these conditions [10]. Images obtained in this mode could provide the initial reconstruction, with zone-axis images used for refinement [11].

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

    SciTech Connect

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

    2015-02-02

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

  14. High-performance probes for light and electron microscopy

    PubMed Central

    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.

    2015-01-01

    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) distribute well in neurons, notably into small dendrites, spines and axons. smFP immunolabeling localizes 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 allow robust, orthogonal multi-color visualization of proteins, cell populations and neuropil. smFP variants complement existing tracers, greatly increase the number of simultaneous imaging channels, and perform well in advanced preparations such as array tomography, super-resolution fluorescence imaging and electron microscopy. In living cells, the probes improve single-molecule image tracking and increase yield for RNA-Seq. These probes facilitate new experiments in connectomics, transcriptomics and protein localization. PMID:25915120

  15. TRANSMISSION ELECTRON MICROSCOPY STUDY OF HELIUM BEARING FUSION WELDS

    SciTech Connect

    Tosten, M; Michael Morgan, M

    2008-12-12

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

  16. 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

  17. 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

  18. Low Voltage Transmission Electron Microscopy in Cell Biology.

    PubMed

    Bendayan, Moise; Paransky, Eugene

    2015-07-01

    Low voltage transmission electron microscopy (LVTEM) was employed to examine biological tissues with accelerating voltages as low as 5kV. Tissue preparation was modified to take advantage of the low-voltage techniques. Treatments with heavy metals, such as post-fixation with osmium tetroxide, on block and counterstaining were omitted. Sections (40nm) were thinner than usual and generated highly contrasted images. General appearance of the cells remains similar to that of conventional TEM. New features were however revealed. The matrix of the pancreatic granules displays heterogeneity with partitions that may correspond to the inner-segregation of their secretory proteins. Mitochondria revealed the presence of the ATP synthase granules along their cristea. The nuclear dense chromatin displayed a honeycomb organization while distinct beads, nucleosomes, aligned along thin threads were seen in the dispersed chromatin. Nuclear pore protein complexes revealed their globular nature. The intercalated disks in cardiac muscle displayed their fine structural organization. These features correlate well with data described or predicted by cell and molecular biology. These new aspects are not revealed when thicker and conventionally osmicated tissue sections were examined by LVTEM, indicating that major masking effects are associated with standard TEM techniques. Immunogold was adapted to LVTEM further enhancing its potential in cell biology. PMID:26026732

  19. Cryogenic Transmission Electron Microscopy Nanostructural Study of Shed Microparticles

    PubMed Central

    Issman, Liron; Brenner, Benjamin; Talmon, Yeshayahu; Aharon, Anat

    2013-01-01

    Microparticles (MPs) are sub-micron membrane vesicles (100–1000 nm) shed from normal and pathologic cells due to stimulation or apoptosis. MPs can be found in the peripheral blood circulation of healthy individuals, whereas elevated concentrations are found in pregnancy and in a variety of diseases. Also, MPs participate in physiological processes, e.g., coagulation, inflammation, and angiogenesis. Since their clinical properties are important, we have developed a new methodology based on nano-imaging that provides significant new data on MPs nanostructure, their composition and function. We are among the first to characterize by direct-imaging cryogenic transmitting electron microscopy (cryo-TEM) the near-to-native nanostructure of MP systems isolated from different cell types and stimulation procedures. We found that there are no major differences between the MP systems we have studied, as most particles were spherical, with diameters from 200 to 400 nm. However, each MP population is very heterogeneous, showing diverse morphologies. We investigated by cryo-TEM the effects of standard techniques used to isolate and store MPs, and found that either high-g centrifugation of MPs for isolation purposes, or slow freezing to –80°C for storage introduce morphological artifacts, which can influence MP nanostructure, and thus affect the efficiency of these particles as future diagnostic tools. PMID:24386253

  20. 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.